#8 in a series of articles about the technology behind Bang & Olufsen loudspeakers
In a previous post, I talked about why a subwoofer might be a smart addition to a sound system – and why a subwoofer brings something different to a Bang & Olufsen loudspeaker configuration than it does for other companies’ loudspeakers.
Usually, in a loudspeaker system that includes a subwoofer, the signal that is sent to that subwoofer is either
- coming in directly from the medium (say, the Blu-ray disc) from the LFE (Low Frequency Effects) channel OR
- created by something called a “bass management system” which is basically a mixer (something that adds audio signals) and some frequency division OR
- all of the above
Let’s assume, for the purposes of this article, that we’re talking about #3. So, let’s start by talking about how a system like that would work. The simple version is that you take an audio input, send it to two different filters, one called a “high pass filter” which lets the high frequencies pass through it and it makes the lower frequencies quieter. The second filter is called a “low pass filter” – you can figure that one out. The output of the high pass filter is sent to your “main” loudspeaker, and the output of the low pass filter is sent to the subwoofer.
That’s what happens if you have a good ol’ fashioned monophonic system with only one audio channel, one main loudspeaker and one subwoofer. Most people nowadays, however, have more than one main loudspeaker and lots of channels coming out of their players. So, in cases like that, we have to take the low end (the bass) out of each of the main channels using low pass filters, add the results all together, add the LFE channel to that, and send the total to the subwoofer. A simple version (with some important details left out, since we’re only talking about basic concepts here…) is shown in the diagram below.
Basics of Signal Addition
Let’s take an audio signal and add it to another audio signal – and, just to keep things simple, we’ll make them both sine waves. This is done by looking at the amplitude of the two signals at a given moment in time, adding those two values, and you get a result. For example:
If you take a look at the example above, there are a couple of things that you can see. The first is that, if you add two sine waves, you get a sine wave. Also, if you add two sine waves of the same frequency, you get a sine wave of the same frequency. Next, if the two sine waves have the same amplitude and are “in phase”- basically meaning that they have the same value at the same time (sort of, but not really like a delay difference of 0) – the result is a sine wave that is in phase with the other two with double the amplitude of the two inputs.
Now, let’s move one of the two signals in time. We’ll make it late by half the length of the sine wave (in time) and see what happens.
Now you can see that, since the bottom plot is the negative of the top plot at any given moment in time (because we’ve delayed it by half a “wave”), when you add them together, you get no output.
Let’s look at one last example, where the two input signals have some phase difference that is not quite so simple. This is shown in the figure below.
Again, you can see that, when you add two sine waves of the same frequency, you get another sine wave of the same frequency. You can also see that the phase (remember – phase is something like delay) of the result is not the same as the phase of either of the two inputs. Finally, you can see that the amplitude (the maximum value) of the result is neither 0 nor 2 – it’s something in between.
So, the moral of this story is that, if you have two sine waves then the result (what you hear) is (at least partly) dependent on how the two signals add – and that result might mean that you get something twice as loud as either input – or it could mean that you get nothing – or you get something in between.
The real world
The three plots shown above illustrate some simple examples of what happens when you have two sound sources that are added together to produce a result. For the purposes of this article, the two sources are two loudspeakers – the “main” loudspeaker and the subwoofer, and the result is the sum of those two signals at your listening position. Let’s go back to thinking about what frequency ranges are produced by these two loudspeakers. The plot below shows the magnitude responses of the filters in a BeoVision 11’s internal bass management system at its default crossover frequency of 120 Hz. The red curve shows the response of the low pass filter whose output is sent to the subwoofer output. The black curve shows the response of the high pass filter whose output is sent to a main loudspeaker.
Take a look at the response of the signal that is processed by the low pass filter. You’ll notice that, although the “crossover frequency” is set to 120 Hz, there is still signal coming out of the filter (and therefore out of the subwoofer) above that frequency – it’s just getting quieter as you go further up and away from the crossover.
You might also notice that, at the crossover frequency, the level of the signal coming out of the low pass filter is identical to the level of the signal coming out of the high pass signal. That’s (more or less) what makes it the crossover frequency. As you move down from that frequency, you gradually get more out of the low pass (the sub) than the high pass (the main). As you move up in frequency, the opposite happens. However, there is a region around the crossover where both loudspeakers are contributing roughly equally (within reason) to the signal that you get at the listening position. So, the “truth” is a little more like the plot below:
I’ve chosen -20 dB as the point where I can start ignoring a signal, but that’s a pretty arbitrary decision on my part. I could have set my threshold higher or lower and still argued that I was right. So, if you disagree with my choice of -20 dB as the threshold of “I don’t care any more” then I agree with you. :-)
By now, you should start to worry a little. You should be asking something like “hmmmm… you’re telling me that there is a big band of frequencies (say, roughly between 1 and 2 octaves) right around where human voice fundamental frequencies sit (well, at least my voice sits there – but I sing bass…) where a bass management system will send the signal out of two loudspeakers!? AND, to add insult to injury, you told me (in the previous section) that if the phases and amplitudes of those signals from those loudspeakers aren’t perfectly aligned, the result at the listening position won’t be the same as the input of the whole system?” If you ARE asking something like that, then you’re in good shape. As has been said by many other people in the past: the first step in fixing a problem is admitting you have one.
So, let’s ask a different question: what parts of the audio signal chain could affect either the amplitude or the phase of the signals coming out of the loudspeakers? Brace yourself… This list includes, but is not exclusive to:
- The characteristics of the filters in the bass management system
- The characteristics of the filtering in the loudspeakers
- The physical principal of the loudspeaker (i.e. sealed cabinets will be different from ported loudspeakers which are different from passive radiators)
- Diffraction (although this might be a small issue)
- Latencies (total delay) of the loudspeakers (for example, digital loudspeakers have a bigger delay than analogue ones typically)
- Distances of the loudspeakers to the listening position
- The characteristics of the room itself
- And more!
All of these issues (including the ones that fall under the “And more” category) have some effect on the phase (and amplitude) of the signal that you hear at the listening position. And, since some of these (like the distances and the room characteristics) are impossible for us (as a manufacturer) to predict, we have to give you, the end user, some way of adjusting your signals so that you can compensate for misbehaviour in your final system.
Now, although this is a “technical” article, I think that it would be too technical to start looking at the specifics of the phase responses of sealed cabinet vs ported loudspeakers, for example, since the details will be messed up by the listening room anyway. So, instead of getting into too many details, let’s just say that “you can’t expect your system to work perfectly without tweaking it” (see the reasons above) and just talk about some strategies for setting up your system so that it behaves as well as it can (without going out and hiring an acoustical consultant).
BeoLab 19 Controls
The BeoLab 19 has a number of controls that have not been available on previous B&O subwoofers. As a result they may cause a little confusion and playing with them without knowing what to expect or listen for could result in your system not performing as well as it could. On the other hand, it could be that these controls could help you improve your system if you’re finding that it’s not really behaving. Let’s take each control, one by one, and explain what it does, and talk about strategy afterwards.
Gain
The gain knob (on the left in the diagram above) is basically just a volume knob that controls how loud the subwoofer is overall. Let’s say, for example, that you have a perfectly configured system, then the outputs of the subwoofer and the main loudspeaker mate perfectly and result in a perfectly flat response below, through and above the crossover region. (this never happens in real life – but we can pretend). The diagram below shows an example of this, where the top plot shows the outputs of the subwoofer and main loudspeaker and the bottom plot shows the total result at the listening position.
If you do nothing but change the gain of the subwoofer, (using the Gain knob on the BeoLab 19, for example) then the result would be something like the plot below.
You can see in the plot above that all you do is to boost a region of low frequencies without doing anything strange through the crossover region. So, if you like bass, this might be a nice tweak for you. However, in theory, your goal is to get a response like the one in the first plot, where the outputs of the subwoofer and main loudspeakers have the same level (at the listening position).
LP Filter
One possible configuration of the BeoLab 19 is to connect it in parallel with your main loudspeakers and to not use and external bass management system.
If you do this, then you are relying on the fact that the main loudspeakers have a high pass filter built-in, and you will align the low pass filter inside the BeoLab 19 to have approximately the same frequency so that the total result is a smooth-ish crossover region. In order for the low pass filter to work, you will have to turn it ON using the switch. (Note that, if you’re using an external bass management system as in the BeoVision 11, for example, then you should turn the low pass filter OFF, thus removing it from the signal path of the subwoofer.)
In theory, the goal here is to match the cutoff frequencies so the two loudspeakers behave nicely together across the crossover region. For example, if the natural low frequency cutoff is about 50 Hz, and you set the LPF in the subwoofer to 50 Hz, then you get the result below
What would happen if you set the LPF incorrectly – let’s say that you make it higher than the correct value, since you would think that, by overlapping the sub with the main speaker, you’ll get more output and impress the neighbours. Well, the result would be the plot below.
As you can see, although the sub is now delivering more signal (because it’s going all the way up to 120 Hz instead of 50 Hz in the previous plot), you actually get a reduction in the total output of the system. This may be initially counterintuitive, but it’s true in our example, since (as you may remember from something I said earlier in this article) the phase of the subwoofer is, in part, determined by the characteristics of the filtering in the loudspeaker. By changing the low pass filter frequency, we change the phase of the subwoofer in the crossover region and result in a cancellation with the main loudspeaker instead of a summing. In essence, both the sub and the main loudspeaker are now working very hard to cancel each other (especially around 80 Hz or so) and you hear very little at the listening position.
On the other hand, I have assumed here that the main loudspeaker’s high pass filter is a very specific type. A different main loudspeaker with a low frequency cutoff of 50 Hz would have had a completely different behaviour as you can see below.
So, the moral of the story here is that setting the low pass filter frequency will have some effect on your total response. However, you should not jump to the conclusion that you can predict what the frequency should be – you will have to fiddle with the knob whilst listening to or measuring the total output of the system. You should also not jump to the conclusion that increasing the frequency range that is covered by the subwoofer in a parallel configuration will result in more output from your system. Overlap is not necessarily a good thing – sometimes, more is less…
Phase
Go back up and take a look at the two sine wave in the plots in Figure 4. One way to describe these two waves is to say that the middle one is half a wave later than the upper one – in other words, they are 180º out of phase. Another way to describe them is to say that the middle one is the inverse of the upper one – they have the same instantaneous value at any time, except that they are the negative of each other (in other words, signal 2 = signal 1 * -1).
So, intuitively, you can see that shifting the phase of a signal by 180º is the same as flipping it upside down. This could mean that, for example, all other things being ignored, that when a kick drum tells your subwoofer to push outwards, shifting the phase by 180º will result in your subwoofer sucking inwards instead. However, this is only true if all other things are being ignored. As soon as your subwoofer has a high pass filter (i.e. a low frequency limit) and a low pass filter (a high frequency limit) and it’s a loudspeaker driver in a cabinet in a room, all bets are off. All of those aspects (and more!) will have some effect on the phase of the system, so you can’t predict whether the kick drum will cause the woofer to put out or suck inwards.
So, instead of worrying about the “absolute phase” of the subwoofer, it’s more interesting to worry, once again, how it matches up with the main loudspeaker. Let’s take exactly the same responses from the plots shown in Figure 14 above (which didn’t add together so well for some reason) and shift the phase of the sub by 180º using the Phase switch. The result is shown below in Figure 15.
As you can see, the big dip in the total response of the system (seen in Figure 14) has been corrected, and we now have more output (actually, a little too much) below that. So, the result is that the total system response is much better than it was without flipping the phase switch.
Of course, if we flipped the phase switch in a system that was behaving nicely, then bad things might happen. Let’s flip the phase on the system shown in Figure 9, for example. That total result would look like the one in Figure 16, below.
As you can see, you get the same amount of low bass in Figures 9 and 16. However, there is a nasty dip at the crossover frequency of 120 Hz when the two loudspeakers are cancelling each other.
So, the moral of the story here is that, if you have a problem in the crossover region between the main loudspeaker and the subwoofer, flipping the phase of one of the two might help the situation – although it might make things worse…
Pos (aka Position)
Almost every loudspeaker in the Bang & Olufsen portfolio has a switch that lets you change the characteristics of the loudspeaker to compensate for the differences in its response as a result of its placement in a room. Generally speaking, the closer you put a loudspeaker to a wall, the more bass you’ll get out of it. If you put it closer to two walls (i.e. in a corner) you’ll get even more bass. However, that is a very general characterisation – the reality is that you’ll get a little more at some frequencies and a little less in other frequencies – and that behaviour is dependent on the diameters of the loudspeaker drivers, the crossover frequencies, and the physical shape of the loudspeaker.
So, without getting into the details of exactly what is being changed in a BeoLab 19 (or BeoLab 2 or BeoLab 11 – or any other loudspeaker for that matter), let’s say that you should put the position switch in whatever setting best corresponds to the location of the loudspeaker in your room. However, if you want, you could cheat a little and fiddle with the switch to see if you like another setting more.
For example, if your loudspeaker is in the corner, and you put it in “free” mode, you’ll get LOTS of bass – too much bass. But if you like bass, this is one way to get it. Of course, there are other implications to this decision, but if you like bass enough, that might be reason enough to change to the “incorrect” the switch setting.
Wired / Wireless
The BeoLab 19 has the ability to receive its input via the analogue or digital input OR via the wireless receiver module that is built into it. This switch merely tells the loudspeaker whether it should “listen” to the wired input (either analogue or digital) or the wireless one. (Note that the BeoLab 2 and the BeoLab 11 do not have wireless receivers.)
L / R/ L+R
Most subwoofers (including the BeoLab 2 and the BeoLab 11) are built with the assumption that you will use them either:
- as a stand-alone subwoofer in a multichannel (i.e. 5.1 or 7.1) system where it gets the “.1” output from the source (that may, or may not have bass management) and so you just send one audio channel into it OR
- in a 2.1 setup where you want the left and right channels coming into the subwoofer where they are added together produce a mono bass signal internally
Consequently, most subwoofers either have 1 input (assuming that they are to be connected to the “subwoofer out” on something like an AVR) or a 2-channel stereo input (assuming that they should “see” left and right) that is summed to mono. BeoLab 2 and 11 are built based on the second assumption.
BeoLab 19 allows you to use the subwoofer in either of these configurations. So, in either “L” or “R” mode, it is only “listening to” the Left or Right audio channel on the Power Link input. In “L+R” mode, the input of the subwoofer is taking both audio input channels and summing them to make a mono input to the subwoofer. Note that, if you send exactly the same signal on the Left and Right audio channels on the Power Link cable, and then you switch the BeoLab 19 from either L or R to L+R, you’ll find that you get a doubling in the output level. This is because a signal plus itself is twice as loud. Since this is what BeoLab 2 and 11 do all the time, if you simply replace a BeoLab 2 or 11 with a BeoLab 19, you should put the 19 in “L+R” mode – otherwise you’ll lose some bass in your system.
However, if you want to use a single Power Link cable to run to the Subwoofer and to another loudspeaker (say, a centre channel, for example), then you should put the BeoLab 19 in either L or R mode (and the other loudspeaker in the opposite mode) so that you can access both loudspeakers independently. This is also the case if you want to run two BeoLab 19’s on the same Power Link cable and use the 2-channel LFE output option in a BeoVision 11. In this case, you se one BeoLab 19 to “L”, the other to “R” and set the Speaker Roles in the BeoVision 11 to “Sub Left” and “Sub Right” (or “Sub Front” and “Sub Back”) appropriately.
Note that, if you are in Wireless mode, the “L/R/L+R” switch does nothing.
How to do it (Finally!)
Method for an Externally Bass Managed Configuration
If your main loudspeakers and your subwoofer are connected to a system that has a bass management system, then you should use it. There are a number of reasons for this:
- the main loudspeakers may behave better (for example, with respect to distortion or port noise) if they are not being pushed by a lot of bass
- a bass management system will work for a multichannel loudspeaker system
- a bass management system (for example, in a BeoVision 11) will be capable of making some “intelligent” decisions with respect to your entire system
- a good bass management system (for example, in a BeoVision 11) will allow you to make fine adjustments to accommodate your configuration and room
So, your procedure here (assuming that you have a BeoVision 11 and a BeoLab 19 and some main loudspeakers) is as follows:
- Turn off the LP Filter on the BeoLab 19, set the Phase to 0, set the Gain to 0, and set the other switches to whatever is best for your particular configuration.
- Put the correct loudspeaker models into the Speaker Connections menu on the BV11.
This will compensate for differences in the latencies and sensitivities of the loudspeakers, in addition to making some intelligent decisions about where to route the bass. - Set your Speaker Distances correctly
This will ensure that you do not have phase differences in the loudspeakers at the listening position as a result of problems caused by the speed of sound and mis-matched distances. - Set your Speaker Levels correctly
On a BeoVision 11, this is done by making sure that, at the same volume level, all loudspeakers produce the same level in “dB SPL, C-weighted, Slow” on an SPL meter like this one, or this one, or this one, for example. - Turn on a piece of music that has a constant bass level
The opening of Freddy Mercury’s “Living on my Own” or Santanta’s “You Are My Kind” are a possible tunes. Claire Martin singing “Black Coffee” is also a good candidate. If you want to look like a professional, then I suppose that you could use pink noise or this track instead of music. - Sit in the listening position and listen to the total behaviour of the system. Pay particular attention to “unevenness in the bass”. In other words, listen to the bass and pay attention to whether some notes are quieter or louder than others.
- In theory, if you performed Step 4 correctly, then you shouldn’t have to play with the Speaker Level in the TV or the Gain on the subwoofer.
- If there is a general area somewhere in the middle of the bass where lots of notes are too quiet, try flipping the phase on the subwoofer.
- If some individual frequencies (or notes) are quiet then playing with the allpass filter on the TV might help.
- If some individual frequencies (or notes) are louder than others, this is probably caused by the room, and you might be able to deal with it by moving the subwoofer. If, when you put the sub in the corner, you make this problem worse, it is almost certainly the room acoustics that you’re dealing with, so moving the sub is your best bet.
Method for a Parallel Connection Configuration
- Turn the LPF frequency as low as you can go
- Turn on a piece of music that has a constant bass level
- The opening of Freddy Mercury’s “Living on my Own” or Santanta’s “You Are My Kind” are a possible tunes. Claire Martin singing “Black Coffee” is also a good candidate. If you want to look like a professional, then I suppose that you could use pink noise or this track instead of music.
- Sit in the listening position and ask someone to turn the LPF as low as it will go.
You should notice that there is a “hole” in the level of the bass between the subwoofer and the main loudspeaker. Turn up the LPF frequency and pay attention whether the “hole” fills up or gets worse. If it gets worse, flip the phase switch and start Step 4 again. - If the hole did not get worse, then keep turning up the LPF frequency until it sounds like there the hole is filled up.
- One you’re done playing with the LPF frequency, try moving the Gain to adjust the bass to the level that you like.
Addendum
There are some more examples of what happens when you play with the various knobs on a subwoofer here.
Dan says:
Thanks for this article. I have a Beovision 10. I assume it also has a bass management system of some sort? Although probably not as advanced as the one in BV 11. Do you know if I would be able to use a Beolab 19 with my BV 10?
geoff says:
Hi,
I believe that the specific bass management in a BeoVision 10 is dependent on which BV10 you have – but I’ll check into this when I get to work tomorrow.
Assuming that your BV10 has Bass Management (you could take a look at the back to see if you have a PowerLink output labeled “SUB”) then you can use the BeoLab 19. You will have to fiddle a bit with the menus to make sure it’s behaving correctly (for example, you have to add about 1.5 m to the Speaker Distance to compensate for the digital processing in the BL19) but it will certainly work.
Cheers
-g
Dan says:
Hi Geoff.
Thanks for the reply. I will have to check the back of the BV 10 tonight. I remember being able to select which subwoofer is connected in the menu system. Although I guess BL 19 wont be in the system. Only BL2 & 11 I think. (since BL 19 wasn’t invented when I bought the BV 10)
cheers
Morten says:
thanks for the article as well. I would appreciate some practical advise if possible
I own BL18’s and currently one BL19
My living room is very large 140m2, i might buy a 2nd BL19 for a 2.2 system.
1) Is there any way to change the low-pass on the BL-18’s, for example cut off the frequencies below 160 Hz?
I am thinking of fx a party or movie, where i would like to maximize the loudness without risk of damaging the main speakers.
2) Can you confirm the correct way to hook up using SPDIF optical cables. Is a 2.1 system is daisy chained: source -BL18(L) – BL18(R) to: (if 2.1:) – BL19(L+R); (if 2.2:) – BL19(L) -BL19(R) , all in random chain order?
Thanks in advance
Morten
geoff says:
Hi Morten,
1. If you only have the 18’s and a 19, then it is not possible to adjust the highpass cutoff frequency of the 18’s. This would require some kind of external device, I’m afraid… On the other hand, if you do push the 18’s, their ABL and thermal protection should protect them (by reducing the low-frequency level – thus making a kind of dynamic-frequency highpass filter… sort of…) so I would not worry too much about damage due to high listening levels.
2. As far as I know, the BeoLab 19 does not have a TOSLINK input, so unless your source has an analogue and a TOSLINK Output, and both are perfectly in sync, you’ll have to go analogue for the system.
One possible solution to both of these issues is to try the B&O wireless transmitter, which would do the bass management for you (I think that the crossover of this device is 120 Hz) and has a TOSLINK input. However, I’d recommend that, if you do want to do this, you should try it in your living room first for the following reasons:
– 140m2 is big in a worst-case. I think that we officially recommend a distance no greater than 12 m between the transmitter and the most distant loudspeaker. Although we’ve pushed the wireless signal much further than the recommended distance (more than 20m), reliability is highly dependent on obstacles and environment…
– I’m not sure if the transmitter will be able to send the .1 signal to two subwoofers (if you get a second BL19). Your dealer will probably be able to help you with this (or be able to try it out…)
Of course, another option is to run the system with analogue, and use an external bass management system. What is your current source? Can it do bass management for you?
Hope this helps!
Cheers
-geoff
felipe says:
Hi,
thanks for the article.
I am planning to make a 5.2 (upgradable in 7.2 system) with:
Beovision 11
4x Beolab 18
2x Beolab 19 in Front, next to the Front Left / Front RIght Beolab 18
How would the connection of the Beolab19 be best? Directly on the Beovision 11, or individually connected through the Powerlink on the Beolab 18?
Does the Beovision 11 surround processor support 7.1 / 7.2 channels to add the rear left and rear right loudspeakers?
Thanks,
felipe
geoff says:
Hi Filipe,
The BV11 has 10 analogue output channels and (if you have the Wireless Power Link transmitter module (this depends on the generation of your BV11)) 8 wireless output channels.
The best way to connect your system would be to directly connect each loudspeaker to the television. That way, the processing such as the crossovers, delays and signal routing can be dynamically controlled by the BV11.
Cheers
-geoff
Morten Jakobsen says:
Thanks for your response ……. You are right, i finally checked the manual and there is no toslink input in BL19. (I am trying to restrain myself from adding a 4 letter word here….)
i got the BL18’s to my home in Thailand, but still need to bring the new BL19(s?) home from the country where i bought them.
My current source is a Mac computer with a 3tb harddrive running Jriver or Roon – using the digital out (3.5 mm combi analogue/optical out), or usb out in other situations.
Back to the thinking box……if i buy/use the 7.1 transmitter, could it deal with a 2.2 system, also if there is unequal distance to the subwoofers?
A few years down the line this problem may go away…..i saw your presentation on the BV avant television. It looked very impressive.
Morten
geoff says:
Hi Morten,
The honest answer to your 7.1 transmitter question is “I don’t know” – but I’ll ask around and try to find out for you.
Cheers
-geoff
Paul McBride says:
Geoff, Hi
I recently resurrected my BL9000/BL8000s with a Moment, ML/NL converter and a receiver for each of the speakers to bring them all to a fully wireless config. So far so good.
Today I added a BL 19 to ‘improve’ the Bass (all connected wirelessly) after reading about how well this works. Except the BL19 doesn’t seem to be producing much bass at all. The moment shows the BL8000’s as ‘other’ and the BL19 as Beolab19 in the wireless setup bso I guess this may have something to do with it, ie the moment doesn’t recognise the 8000s so thinks they’re something else. I have followed all instructions to no avail. Any insights would be welcome apart from the need to go ‘wired’!
Thanks for the articles in any case, they’re awesome!
Thanks,
Paul
geoff says:
Hi Paul,
I’m working on trying to find out the answer to your question. However, I suspect that the problem is that the 8000’s Speaker Type is set to “Other”.
I’m going to try to re-create your setup (please be patient with me – I might not be able to do this until after Christmas…) and see what happens.
I now that this does not solve your problem immediately… I notice that you have asked the BeoWorld forum people to help as well. Hopefully, they can provide an answer faster than I can.
Cheers
– geoff
Paul McBride says:
Geoff, hi
Thanks very much for the response, and yes of course I’ll wait and see if you uncover some insights in the new year. I’ve pretty much done all I can as far as resetting, reconfiguring and reinstalling are concerned and have submitted logs via the moment this evening in the hope that a diagnosis is possible.
Thanks again,
Paul
Paul McBride says:
Geoff, Hi
Just a short note to let you know I found a solution/workaround to the problem. I connected the 8000s to the moment using PL ‘wires’ whilst leaving the BL19 in wireless mode. As with the wireless setup, the speakers show up, as ‘other’ in wired mode and the 19 does not produce bass. However, in wired setup mode on the moment you are offered two additional options to select the speaker type – as either Beovox1/2 (the age of these speaker options meaning little to no functionality or UI testing on this part of the UI :) Selecting either beovox option solves the problem and the bass comes through on the 19. So sweet. This is where reading your articles pays off and setting it up proved a joy when listening to the newly configured wired/wireless system.
So the next stage was to unplug the wired speaker, plug back in the receiver 1, activate it as ‘other’ in the wireless setup. Experience delight that the 19 is still pushing out the bass notes, Repeat the same process for the other speaker and lo and behold it all works. Wirelessly!
I guess the moment Dev team need to update the software to fix this. Hopefully that can come soon.
I really appreciate your willingness to reproduce my problem and am humbled that you even considered it important enough to respond. I’m delighted to have saved you the time doing this.
Best wishes,
Paul
geoff says:
Hi Paul,
My apologies for not suggesting that you wire your 8000’s – of course this solves the problem – but I thought that wiring was not an option for you (I think that you wrote that in the beoworld forum posting, maybe?).
I’m curious as to why you do not select the BeoLab 8000 as the speaker type instead of the BeoVox. There is a small difference in sensitivity of the two loudspeakers which is accounted for in the software. (It’s only about 2 dB, so the difference is not night-and-day. More like night-and-later-the-same-night…
Anyways, glad to hear that you’ve got it working as you wish. I’ll still look into your original issue, since it should have worked for you in the first place.
Cheers
-geoff
Paul McBride says:
Geoff, Hi
Thanks for the reply – Yes, wired is not a solution for me but when it came to the end of troubleshooting the problem I was getting desperate and wanted to try wired as a last resort to see if the problem manifested itself in this type of setup. Here’s what was odd. On my Moment, the only options offered when the speakers were wired were BeoVox1/2, nothing else. I have the latest version of the software (I saw an updated overnight this morning so maybe that addresses the limited options) so I just chose this option.
Once I ‘applied’ the BeoVox 1 selection, the 19 came on. When I unplugged the wires and went back to wireless via the receiver 1’s on the 8000s, the 19 still worked. It’s almost as if wiring the 8000s to the moment ‘freed’ the 19 to play bass. I really don’t know why.
Either way, it’s all good!
Thanks,
Paul.
Spiro says:
Hi Geoff
I’m finding it really difficult to determine if there is a HPF being applied to the Power Link Outputs on the BeoLab2. I would really appreciate it if you could find out for me.
Many thanks.
Best regards
Spiro
geoff says:
Hi Spiro,
Easy. There is.
Cheers
-geoff
Jean-Christophe says:
Dear Geoff,
Thank you for this detailed topic and all your explanation. However, I have a specific issue with my own setup : BV11-55 mk3 + BL1 (front) + BL8000 (surround) + BL19 sub (WISA connected). I cannot find the BL1 in the Bass Management chart of the B&O Technical Sound Guide. I would like to benefit from the bass of my BL19 when listening to music (2ch stereo signal) on my Beolab1, because these speakers lack a little bit of bass frequencies (to my personal taste).
I did not succeed to make both the BL1 and BL19 work together on a stereo signal. I previously had a BL2 sub that worked flawlessly both with 5.1 or 2.0 signals. Can you help please ? Many thanks in advance.
Jean-Christophe
geoff says:
Hi Jean-Christophe,
My apologies for taking so long to respond.
It is possible with the BV11 to do exactly what you want, using the following steps:
go to MENU -> Sound -> Speaker Connections
and set the speaker types appropriately (I assume that you’ve already done this)
go to MENU -> Sound -> Speaker Groups -> YOUR_NAME_HERE -> Speaker Roles
and set the roles for the loudspeakers as you want them, including setting the BeoLab 19 to SUBWOOFER
go to MENU -> Sound -> Speaker Groups -> YOUR_NAME_HERE -> Advanced Settings -> Bass Management -> Enable Filtering
and set the values for the Beolab 1’s to ON
This should re-route the bass from the BeoLab 1’s to the BeoLab 19, as you wish.
For more information on the other capabilities of the BeoVision 11’s signal routing capabilities, please see the Technical Sound Guide which you can download from the link on this page.
Hope this helps
cheers
-geoff
Jean-Christophe says:
Dear Geoff,
Thank you so much for your reply ! And please do not worry about the time needed for reply, after all, it’s summer holidays (I hope for you also :-)
Now on stereo signals, my Beolab 19 functions in combination with my Beolab 1 :-)
The only “mystery” that remains for me is why, previously, my Beolab 2 was always functioning on stereo signals without the need to adapt the Bass Management (?) IMHO it should have been the same with the BL19 since both these subs provide a lot more bass than the Beolab 1.
Cheers,
Jean-Christophe
Cedric says:
Hi Geoff,
I hope that you can help me with this problem. I have two BL18 (1 pair), each connected with Beosound Essence (BE) via power links and they worked beautifully.
Recently I added a BL19, so I use power link to directly link two BL18, and then the BE is linked to one BL18 and the BL19. On BL19 I tried all of the combinations (including the recommendation as per BL19 manual: Gain: 0, LP: On at 80, Phase: 0, POS: W, Wired, L+R), BL19 is powered and producing some sound but none of the combinations can produce the same subwoofer effect I heard in showroom using the same music on my iPhone (far from that great bass effect).
Am I doing anything wrong?
Many thanks!!
geoff says:
Hi Cedric,
Sorry it took so long to respond. I’ve been on vacation – also from my computer.
You’re not doing anything wrong – but there are some things to check, and then adjust…
Since you say that there is sound coming from the 19, then the issue is one of adjustment… This is not surprising, since the placement of your loudspeakers and the effects of the room will require that you do some tweaking.
Don’t be afraid to “break the rules” – just because the knobs on the 19 look weird doesn’t mean that things are not calibrated correctly for your configuration…
Some basic things to try out:
1) Turn up the gain on the 19 all the way. Hopefully, this should give you the potential to have FAR too much bass in your system.
2) Turn the gain down until it sounds balanced for you in the listening position (you might want to get someone else to do the knob turning for you).
3) While listening (in the listening position) switch the PHASE between 0 and 180. Pick the one that is generally louder. You might need to listen for a while to notice a difference. This is because you might only be affecting a frequency range that doesn’t happen to be playing in the tune at the moment…
4) Next, adjust the LP filter frequency (still while listening). At normal listening levels, the 18’s can deliver 80 Hz, so unless you listen at higher levels, you don’t need to have the sub covering that frequency range. I’d bring it down to 50 Hz (give or take). However, if you do listen at higher listening levels, then a LP filter at 80 to 120 Hz is probably a good idea.
5) After adjusting the LP filter, you might need to go back and adjust the gain and/or the Phase again, using the same methods described above. This is because you have changed the total bandwidth of the subwoofer (and therefore the apparent level) and the phase (because the LP filter has an effect on the phase of the output).
Try this out with someone patient enough to help you out and let me know if this helps.
Cheers
-geoff
Nick says:
Hello,
I recently bought a used pair of Beolab 18s, daisy chained the left to the right with a power link and connected the right 18 to a connection hub I bought on amazon. The connection hub is connected to my Panasonic plasma via toslink. Everything works beautifully, but I wanted to improve it further so I ordered a Blueaudio Node 2 and a Beolab 19. I would like to scrap the connection hub potentially and just use the Blue Audio Node 2.
I was planning on keeping the left 18 connected to the right 18 with a power link cable and connecting the right 18 to the Node 2 with either a toslink or RCA. What would be optimal to connect the 19? Do I power link it to say the left 18 since that is the closest speaker to where I want to place the 19 in the room or do I connect the 19 with a subwoofer cable directly to the Node 2? Based on what you think is the best connection then what would be the best configuration on the 19? Thank you,
Nick
geoff says:
Hi Nick,
If you’re planning on using the analogue output of the Node 2, then both of the options you describe should work – but they’ll probably work differently… If you simply daisy-chain the 18’s and the 19, as you describe, then you might have to fiddle with the Low Pass filter on the 19 to get things to sound nice – particularly in the frequency band where it overlaps with the 18’s. I briefly looked at the manual for the Node 2 and I could not see any detailed information there about how they’re doing the bass management. If you choose this option, make sure to start with the Low Pass Filter disabled on the BL19, so that it does not initially conflict with the external bass management.
So, my advice is to try both of the two options you describe, and choose the one that you prefer. They’ll certainly be different…
Cheers
-geoff
Nick says:
Geoff,
Thank you for the response. I decided that I will purchase a transmitter 1 to go along with the 19. This way I can place the 19 in the back of my living room where I have a nice space for it and have bass management as well. I was reading the transmitter’s specs online and was a little confused still. Do my 18s need to be connected wirelessly as well for the bass management to work? I figured it might be easy to just connect the 18s via power link and only have the 19 wireless… Thanks,
Nick
geoff says:
Hi Nick,
There may be two issues to consider with your plan…
If you connect the 19 wirelessly via a Transmitter 1, but the 18’s are connected using Power Link wires, then the Transmitter does not “know” about the 18’s. This means that there will be a slight (< 5 ms) delay difference between the 18's and 19's (equivalent to having the 19 placed about 5 feet or 1.7 m further than the 18's). Also, the 18's will not be high-passed filtered (as would also be the case if you connected everything via Power Link). If you're going to try out the Transmitter 1, then I would suggest that you use it for the 19 and the 18's. This will cause it toautomatically look after the bass management for you, and correct both of these issues. Of course, you could always connect the 19 via the Tx1 box, and the 18's via Power Link and have a listen - then switch the 18's over to the wireless connection and have a listen - and then choose the one you prefer. Cheers -geoff
Ki says:
Hi Geoff,
There’s something I’m not sure about my Beolab 4PC + Beolab 11 setup. I hope you could give me some advice…
I have a pair of Beolab 4 PC version. They were originally connected directly to a 1st generation Playmaker (with a RJ45 to 3.5mm cable). I liked the sound and then later I bought a Beolab 11 as an upgrade. Then the Beolab 11 was connected directly to the Playmaker and the Beolab4PCs were connected to the Powerlink output of the BL11.
The LINE-IN switches on both Beolab4PCs have always been set to AUTO. They are 8 inches away from rear wall. One is approx 1.5ft from the side window behind a curtain and the other is free from side wall.
My Beolab 11 is placed on the floor around 8 inches from the rear wall and 4 inches from the side panel of a glass shelf. (I guess this makes it a “corner” position)
At first, I have the Beolab 11 set up according to the User Guide:
– Input switch was kept as Powerlink
– Bass management was kept as INT.
– The sensitivity switch was set to -dB (according to the manual when connecting to BL4PC)
– The position was set as POS.3
But the result was a bit strange, the bass was obviously muted compared with the previous setup where the BL4PCs were on their own. I remember I read somewhere suggesting that the BL4 Powerlink version has different Line-in sensitivities (PC= compensating for higher input level from headphone jacks and LINE= compensating for lower input level from pre-amps).
So I wondered, when I set the LINE-IN switch on the BL4PC to AUTO (which assumes I connected the speakers to audio system pre-out according to the manual) and that the pre-amp was actually a Playmaker instead of headphone jacks, should I set the level switch on the BL11 to 0dB?
Anyway, I tried flicking the switch to 0dB… then the sound was “Ok” for some recordings (usually classical records) but was overly booming for some recordings (in particular, some jazz records, e.g. Carol Kidd – A nightingale sang in Berkeley Square, and some pops).
Then I also tried level switch -dB with POS.1. The result was better on jazz & some pops but bass seem to be a bit muted on most classical recordings including piano solo, and also some pops.
After reading your blog I understand that the room is also a major factor on the sound and I can try different position for the BL11.
So I think at least I should have the settings “technically” correct before trying anything else. And my main concern is that, with the input switch set to AUTO on a BL4 PC, should I set the sensitivity switch to -dB or 0dB on the BL11? Much appreciated if you could help.
BTW I have to say that the Beolab 17 is absolutely awesome when placed right (my family have a pair)! Most impressive among others is, every “instrument” just sound clearly defined. I think they deserve better placements in showrooms to impress.
Thank you and sorry for the lengthy post..
Ki
Kasper says:
Hi Geoff. I have Essence, Transmitter 1 and BL18 + BL19. When I listen to music from Spotify or Dezer it’s just perfect and BL19 is doing a great job. But watching a movie BL19 is nearly at sleep… the bass management i strange compared to music. I have a Samsung TV connected to the Transmitter via Toslink. It’s the same with HDMI/ARC to phone or mini jack connected to Transmitter. How do I get full movie power in my BL19…
Thanks for some fantastic products!!!
geoff says:
Hi Ki,
To start: One thing to know about the BeoLab 4 PC is that it has a different sensitivity than the rest of the BeoLab range. This is because the “PC” part of the product meant that it was built to expect less output from the source (a headphone jack of a PC). Consequently, it has more gain than a normal BeoLab 4.
In other words, if you sent exactly the same signal to a BeoLab 4 and a BeoLab 4 PC, the latter would be significantly louder (I can’t remember if the number is 10, 12, or 14 dB – but it’s something in that ballpark.
So, this means that if you use a BeoLab 11 to do the bass management, and you use its Power Link output to send the signal to a BL4PC using an adapter cable to the mini-jack input, I would expect the result to be “bass light” – since the BL11 is expecting less output than the BL4PC is delivering.
The truth is that I have never tried the configurations you’re describing (the BL4 is before my time…) and it would, of course, be impossible to duplicate your acoustical conditions.
That said, I would say that, even if there is a “technically correct” solution to the settings on your loudspeakers, if I were doing the setup for you, I would ignore all of those and play with the parameters until it best matches your taste. As it says in the manual, I would certainly start with the “- dB” setting on the sub (since that’s intended for the BL4PC) and play with the POS switches and the sub’s placement in the room (if feasible) to get the best result. If that still doesn’t give you enough bass, then it may be worth considering a third-party passive volume control with a minijack in and a minijack out (look for something like “in-line headphone volume” – it should cost less than $10) – to reduce the gain of the BL4’s to match your BL11’s output.
I hope that this is enough information to help – sorry I can’t give you better “tips and tricks”. However, if you do try this out and it doesn’t work to your expectations, please get back to me and we’ll see what else can be done.
Cheers
-geoff
geoff says:
Hi Kasper,
I need a little more information:
How is the Essence connected to the BL 18+19? Is this using Power Link in a parallel connection, or is it connected via Power Link to the Transmitter 1 box, or is it something else?
If both the Essence and the TV are connected to the Transmitter 1, and the speakers sound good with one of those two sources, then I suspect there’s something going on with either decoder or the audio settings in the TV.
However, if you’re using two different paths (e.g. Power Link for the Essence, and Wireless Power Link for the TV through the Transmitter box) then there are two different signal processing chains going on – and this might explain the difference.
Please let me know more about your signal path configuration and we’ll try and sort things out.
Cheers
-geoff
Cheers
-geoff
Ki says:
Hi Geoff,
Thanks a lot for the insight. I’ve actually settled with -dB, too. Guess I may try different placements.
Regarding speaker placement & the position switches on most Beolab speakers, there’s another question in my mine for long time.
We used to have a pair of Beolab 9 in an office place. The biggest concern was, it’s a “glass house” type of office. It’s overall a rectangular space with both long sides essentially fixed glass windows from floor to ceiling (except there’s an glass door on one side). Both short sides are kind of sandwich with glass on the surface glued on wood board behind the glasses & then the concrete walls behind the wood. And within that office space, all partitions between rooms are glasses as well.
The BL9s were both placed close to the glass window behind (probably less than a ft away), one was close to a glass partition on the side and the other close to the “sandwiched’ glass wall on the side. The listening position is in the middle of that room and formed a 6ft-6ft-6ft (or 7-7-7, forgot) triangle with the speakers.
On first setup, we used “corner” position on both BL9s. But then for quite some time, most of us still “felt” that the BL9s sounded a bit aggressive on the high freq. & a bit bass light (we did hope that giving the BL9 some ‘run-in’ time for weeks could help). Not quite like what we heard on showrooms. I’ve heard that people say “glass” rooms are generally very bad in terms of acoustics for hi-fi. I searched a bit and found some claiming that low frequencies are more likely transmitted through glass plates than reflected. I’ve been wondering for long time, if that’s true should both the BL9s be set with “Free” position? I guess B&O might have done some research or test with speakers in rooms with huge glass windows or partitions? Since I have the impression that most modern Scandinavian homes/offices are like that (but maybe I’m wrong).
We finally settled with position switch on “WALL” and put 2 large pieces of acoustic foams on the side wall around the first reflection centred at tweeter height. Looks bad but too bad the Beosound Shape absorption tilts weren’t out yet. Hope you can shed some light on this long time question in my mind.
Thanks!
Ki
geoff says:
Hi Ki,
Imagine putting a blanket on a clothes line, and then hitting it repeatedly with a baseball bat. The blanket is very good at absorbing the impact of the hit – and you’ll get tired quickly without achieving anything.
It is not unusual for a large panel that can vibrate (like a pane of glass, or a sheet of drywall between two studs) to act the same way. So, the low frequency sound wave “hits” it (like the baseball bat hitting the blanket) and causes it to move. This has two effects – one is that the other side of the glass acts as a loudspeaker – so, effectively, the sound is transmitted through it. The other is that the movement of the panel generates heat inside it, and that energy is just lost (or absorbed).
However, for high frequencies, a pane of glass is very reflective.
So, the end result, as you have described is an overall “brightness” in the sound in your room, since (generally speaking) the low frequencies are lost, and the high frequencies are not.
One solution is to just get used to it. This is a bad solution if you don’t like the sound. :-)
The second solution is to do change the absorption / tranmission somehow – this is what you’ve done with the acoustic foam – you’ve absorbed some of the high frequency information to bring it in balance with the lows. You could also substitute your glass with concrete, but the view will not be improved…
A third possibility is to push more bass out of the speakers – as you suggested, by putting them in “free” mode, for example – or turning up the bass (or down the treble) in your audio source.
Any of these will work with varying results – a combination of these might be the best solution.
Hope this helps.
Cheers
-geoff
Ki says:
Hi Geoff,
Thanks for the elaboration! Btw, The foams I put next to the BL9s actually had a “side effect” like what you usually mentioned regarding beam width control, they improved the stereo imaging/focusing of the BL9s a bit. And though it’s not likely to happen, I do wish you/B&O could consider to release some kind of “ALT cheeks” sets (perhaps made of “non biodegradable” foams) tuned to narrow the beam width of other ALT beolabs, in particular the BL9s :-)
Cheers
Ki
Jan Bødskov says:
Hello Geoff
Quick question – if you had a Beoplay V1-40 like me and a set of Beolab 3’s and auditioning a used Beolab 2 what would your setting for the speakers/sub look like? For movies/tv and for music? The BL2 is connected to the V1 and so are the BL3s.
Best regards
Jan
geoff says:
Hi Jan,
This may sound crazy, but one thing that is worth trying is to make your V1 the Front Left / Front Right loudspeakers, and use your BeoLab 3’s as surround loudspeakers (in the surround positions). The BeoLab 2 should be placed somewhere near the TV, or in a corner of the room with the Position Switch in the correct position, and the gain adjusted appropriately in the TV. Of course, this won’t be great for music – but it’s not a bad surround configuration.
Apart from that, if you just configure the basic menus correctly, the Advanced Settings in the V1 will look after themselves.
Cheers
– geoff
Jan Bødskov says:
Hi Geoff
Thank you! Will try it out : )
Enjoy the sunny Sunday!
Best regards Jan
geoff says:
Hej Jan,
Tak! I lige måde!
Mvh
-geoff
Jan Bødskov says:
Tak for det : )
Gains = db settings in this case?
Mvh
Jan
geoff says:
Exactly.
Mvh
-geoff
Z says:
Geoff! I’m so happy I found your site. So much useful information.. Thank you for putting this info out here for us. I’d like your advise on something. I have a pair of BL3s connected to BeoSound Essence mk2. I’m going to add a sub to get more volume out of the system. My question is, where would say the crossover should be approximately? I’m asking because I have to get a low cut filter on RCA level and there are really no good variable filters out their, leaving me to get a set filter. I’m looking at 100hz cut on the BL3s, would that be enough? The sub is a very potent velodyne 1000 ultra.
Thanks again!
geoff says:
Hi Z,
It’s really impossible to know exactly what the best crossover frequency would be, since this would depend on the frequency where the maximum capability of the two BeoLab 3’s in unison equal the maximum capability of your subwoofer.
So, that said, I would say that it should not be higher than 120 Hz – but as low as possible to reduce the potential for localising the sub. In addition, I would recommend that you try a 4th order Linkwitz-Riley crossover – however, I would also warn that this may not be the best solution, since the integration of the BeoLab 3’s with the sub is extremely dependent on the relative phase responses of the loudspeakers.
Cheers
-geoff
Z says:
Geoff! You just gave me alot more to do and I have very little time for a diy 4th LR haha! You rock man, thanks :)
geoff says:
Hi Z,
You could “cheat” and use something like this
https://www.minidsp.com/products/minidsp-in-a-box/minidsp-2×4
Cheers
-geoff
Z says:
This thing is almost custom made for my needs! Thanks again Geoff!
Siggi Hoffmann says:
Hallo Geoff,
First of all thank you for your extraordinary support.
I have a question in connecting my beolab11 to BV11. I set Powerlink Output 3left to the Subwoofer (Role is Subwoofer) and Powerlink Output3right to my beolab8000.I connect the Powerlink Cable to the Input Beolab11 and from its Output (right) i patch to my Beolab8000(right).Is that ok? and do i have other „special „ adjustments to do?.
Sorry about my bad english and greetings from Heidelberg/Germany
Siggi
geoff says:
Hi Siggi,
I was just reading about Heidelberg yesterday! I was digging into the history of some fountain pen manufacturers there – specifically the Hebborn/Luxor company, the Peter Bock company, and their relationship to a Danish company called Big Ben. However, that has nothing to do with BeoLab speakers… :-)
I need to do a little research to correctly answer your question… The reason that I’m about 99% sure that there is no way to tell the BeoLab 11 to only play the left channel of the Power Link cable.
So, in order to put the BL11 and the BL8000 on the same PL output, you’ll need a special Power Link splitter that does NOT send both channels to both loudspeakers. This will ensure that the Right channel is not played by the BL8000 and the BL11 at the same time.
The easy way out of this is to use a different Power Link output for the BL11 than the other loudspeakers (for example PL3 to the BL11 and PL4 to the BL8000). Then you can either tell the BV11 that one BL11 is connected, or two – the BV11 will compensate automatically for this (I think that I wrote about that in the BV11 Technical Sound Guide – but it’s been a long time… I’ll check on this as well…)
If the PL3/PL4 solution is an option for you, then please do this and let me know. Otherwise, you’ll need to find that special splitter cable.
After this, then it’s just a matter of correctly configuring the menus for Speaker Type, Speaker Role, Speaker Distance, and Speaker Level. That will be a good start – and you can tweak things to taste from there.
Please let me know if I can help more than this.
Cheers
-geoff
Siggi Hoffmann says:
Hi Geoff,
Nice story about the pen factory ;o)…and many thanks in answering.Ok i understand this „splitting or two Pl-Cable Option“.But,when i do this PinkNoise Speaker Volume Setting..all Speakers working right.The Noise is coming from the choosen Speakers in that „Test“.So,i thought that there are connected correctly or do i think wrong?
Cheers Siggi
geoff says:
Hi Siggi,
If you tell the BV11 that a channel is not a subwoofer, then the pink noise sent for the Speaker Level will be band-limited. Consequently, there will not be much coming out of the BL11, but there will be something. As soon as you turn on an audio signal, then the BL11 will “sing along” because the audio will not be band-limited enough to prevent this.
Cheers
-geoff
Harry says:
Hi Geoff,
I have Core, Transmitter 1 and BL18 + a pair of BL19. The bass on the 19 is very underwhelming so I was wondering if you could help me with the setup (Gain and the LP Filter values and also should I enable the sub 2.1 switch on the Transmitter 1).
Cheers,
Harry
geoff says:
Hi Harry,
In order to help (if I can) I’d need some more information. What exactly do you mean by “underwhelming”? Is it just not loud enough? Or is there something else that is not meeting your expectations?
Cheers
-geoff