Stereo Sub Vs Dual Mono

[FrankW]

My experience is that for most material it actually doesn't matter much one way or the other. The majority of the signal is mono anyway.

https://www.audiosciencereview.com/...s/stereo-sub-vs-dual-mono.43767/#post-1554521
If you have evidence the majority of classical, jazz etc is still being distributed with mono bass after the LP/Vinyl era (where it was necessary), please provide links, thanks.

 

[sigbergaudio]

https://www.audiosciencereview.com/...s/stereo-sub-vs-dual-mono.43767/#post-1554521
If you have evidence the majority of classical, jazz etc is still being distributed with mono bass after the LP/Vinyl era (where it was necessary), please provide links, thanks.

I do not have that, also did not claim that it was.

If I did listen to genres where bass is often recorded in stereo, I think I would actually opt for dual mono, since the benefit of more even response will probably outweigh lost stereo perspective, due to the fact that localization cues from the speakers means there won't be much loss of stereo perspective in practice.

That being said, everyone is of course free to test and decide for themselves.

 

[FrankW]

If I did listen to genres where bass is often recorded in stereo, I think I would actually opt for dual mono, since the benefit of more even response will probably outweigh lost stereo perspective

That is a false dichotomy presuming one can't have "even response" with non-mono bass. Not to mention you are referring to "visual" response, not audible, as determined by the type of double blind listening tests I link. Not the same thing. Audio and visible perception are different.

due to the fact that localization cues from the speakers means there won't be much loss of stereo perspective in practice.

You are not understanding localization has nothing to do with lateralisation aka the ability to detect spatial differences below localization frequencies. links have been provided. Thread title is "Subs", aka <80-90Hz

That being said, everyone is of course free to test and decide for themselves.

Well of course preferences vary, so those who listen only to mono bass/no fi music need not fret non-mono bass. OTOH, those who have been to concert halls may want some semblance of spatial fidelity. YMMV

 

[goat76]

You say crossover but there is only a LP filter on the sub isn't it? There is nothing that "crosses"?

May I ask how you decided on the LP frequency and slope/order of the sub?

Well, the setting on my REL subwoofers is named “crossover” even if it's just a low-pass filter with a 12 dB/octave slope, and my main speaker's natural roll-off is the "high-pass filter" and as the ATC SCM40 are sealed speakers they have a natural roll-off slope of 12 dB/octave.

 

[sarumbear]

Well, the setting on my REL subwoofers is named “crossover” even if it's just a low-pass filter with a 12 dB/octave slope, and my main speaker's natural roll-off is the "high-pass filter" and as the ATC SCM40 are sealed speakers they have a natural roll-off slope of 12 dB/octave.

Thank you, I understand. I am simply trying to use correct terminology instead of “market speak.”

Have you measured the f3 of the speakers, or used trial and error by checking the overall response?

 

[theREALdotnet]

If I did listen to genres where bass is often recorded in stereo, I think I would actually opt for dual mono, since the benefit of more even response will probably outweigh lost stereo perspective, due to the fact that localization cues from the speakers means there won't be much loss of stereo perspective in practice.

I tried some simple visualisations once and found that stereo channel separation reaches far down with most material. This is from a 1970s pop track, low-passed at 30Hz from memory:

Only some material (for example with synth bass) tends to have truly mono bass, showing a vertical line in the tool above. Sorry, I didn’t care enough to spend money on better tools.

That said, after playing around with various configurations of two subs and different cross-over points I have yet to hear a difference in spatial effect, envelopment or imaging. At least nothing that wouldn’t easily be swamped by the slightly different frequency responses of the various configurations (the DSP filter calculations come up with somewhat different solutions each time). There is a noticeable difference between using one sub and two subs in mono, though.

In short, nothing to lose sleep over.

 

[goat76]

Thank you, I understand. I am simply trying to use correct terminology instead of “market speak.”

Have you measured the f3 of the speakers, or used trial and error by checking the overall response?

I have done measurements of each channel separately to find the most optimal crossover settings and level settings for each subwoofer to match the corresponding main speaker (left subwoofer to the left main speaker, and right subwoofer to the right main speaker).

As I previously mentioned, my speaker setup is not symmetrically positioned in my listening room for practical reasons. This will unavoidably cause an uneven bass response between the channels but thanks to the possibility of setting the subwoofer's crossover (low-pass filter) individually for each channel, I can now compensate for the loss of energy in one of the channels just by applying a higher crossover point. This way, I get an even response at the main listening position even though my speakers are not positioned symmetrically in the room.

 

[Wizard509]

Noob (quite possibly displaying his ignorance) here. Has anyone done any "stereo sub vs mono sub" testing using a binaural microphone located at the primary listening position?

 

[goat76]

If I did listen to genres where bass is often recorded in stereo, I think I would actually opt for dual mono, since the benefit of more even response will probably outweigh lost stereo perspective, due to the fact that localization cues from the speakers means there won't be much loss of stereo perspective in practice.

An "even response" is hardly what someone seeks if they are interested in taking part in the effects stereo bass brings to the party, quite the opposite actually as the differences between the channels are the main reason for going in that direction in the first place. Without any differences, there's simply no point in doing it.

But as you say, many recordings don't contain much or any stereo information in the sub-bass region, so for all those recordings you still get the same "even response" no matter if the subwoofers are setup in stereo or mono because the two subwoofers are getting the same signal anyway in those cases.

As I see it, it's a win-win situation no matter what you prefer.
- If you prefer to always get an even bass response, go for mono subwoofers and you will always have your even response.
- If you prefer the effects of stereo bass, you get that when the recording contains such information. And when the recording doesn't contain such information, you will at least have the same even bass response as if the subwoofers were set up in mono because they will receive the same signal anyway.

 

[sigbergaudio]

An "even response" is hardly what someone seeks if they are interested in taking part in the effects stereo bass brings to the party, quite the opposite actually as the differences between the channels are the main reason for going in that direction in the first place. Without any differences, there's simply no point in doing it.

But as you say, many recordings don't contain much or any stereo information in the sub-bass region, so for all those recordings you still get the same "even response" no matter if the subwoofers are setup in stereo or mono because the two subwoofers are getting the same signal anyway in those cases.

As I see it, it's a win-win situation no matter what you prefer.
- If you prefer to always get an even bass response, go for mono subwoofers and you will always have your even response.
- If you prefer the effects of stereo bass, you get that when the recording contains such information. And when the recording doesn't contain such information, you will at least have the same even bass response as if the subwoofers were set up in mono because they will receive the same signal anyway.

When I say even response, I do not refer to differences between channels, but that for instance 30hz and 100hz is reproduced with the same difference in level as on the recording (so not affected by the room). This is more likely to happen in a dual mono subwoofer setup than in a stereo subwoofer setup.

 

[Deleted member 48726]

There is the placement issue in stereo use which has been noted by others. If your main speakers are placed together with each sub it's rarely the OPTIMAL place for the bass driver in the room. When using two subs and feeding them mono/summed signal you can place them where you get the most out of them in-room.

 

[sigbergaudio]

That is a false dichotomy presuming one can't have "even response" with non-mono bass. Not to mention you are referring to "visual" response, not audible, as determined by the type of double blind listening tests I link. Not the same thing. Audio and visible perception are different.

You are not understanding localization has nothing to do with lateralisation aka the ability to detect spatial differences below localization frequencies. links have been provided. Thread title is "Subs", aka <80-90Hz

Well of course preferences vary, so those who listen only to mono bass/no fi music need not fret non-mono bass. OTOH, those who have been to concert halls may want some semblance of spatial fidelity. YMMV

1) I haven't said it is impossible to have even response with non-mono bass, but it is unlikely that two subwoofers placed in two different locations in the room both have even frequency response. That means that for your listening position, you have actually found two different positions in your room where there are no dips between 20-80hz, and both those locations happen to be quite close to your speakers (I assume you place your speakers symmetrically and close to your speakers if you prefer stereo bass). This does not seem like a very likely scenario, but I guess it can happen.

2) I do think I have a pretty good understanding of both localization and lateralisation. I wouldn't go so far as to say that they have nothing to do with each other, but I understand that there are differences. Assuming your reference is to this paper? http://www.acoustics.asn.au/conference_proceedings/AAS2008/papers/p47.pdf - from my brief understanding having skimmed the paper, it proves that it is possible to detect channel differences in sinus tones as low as 31.5hz (barely) and at least 40hz. I have not challenged this. What I have said is that most sources of low frequency sound also contain harmonics that reach well into the audible band. From this we can deduce that you will still perceive channel differences despite the fact that the reproduction below 80hz has been forced into mono. Please also note that I'm discussing dual mono vs stereo (as that seems to be the topic of the thread). I'm not talking about a single sub setup. This means you will actually have a sound source placed close to the speaker, so a coherent sound source, only the lower frequencies are mono. This is not the same situation as a single sub placed somewhere else entirely. In a dual mono setup, I maintain that the loss of laterialisation will be low.

 

[abdo123]

My subwoofers created a phantom center even with a very high slope crossover at 80Hz.

Even though I loved having two subwoofers at both sides of the listening position it felt really artificial after almost a year.

Getting the subs and the speakers close to each other kinda brought back the depth continuity that good stereo setups have. A lot of people focus on stereo imaging with regards to left right and center but front and back have so much going on as well and a good bass managed setup should preserve that imo.

my next upgrade will be to a multichannel setup, so maybe that will change my mind in terms of where to put subwoofers, I will also probably get my subwoofers count to 4.

But it's so much money right now so it will probably happen in the next two years as i'm very happy with my current setup right now.

 

[goat76]

When I say even response, I do not refer to differences between channels, but that for instance 30hz and 100hz is reproduced with the same difference in level as on the recording (so not affected by the room). This is more likely to happen in a dual mono subwoofer setup than in a stereo subwoofer setup.

That's where things like acoustic treatment and EQ adjustments come in.

 

[FrankW]

I do think I have a pretty good understanding of both localization and lateralisation. I wouldn't go so far as to say that they have nothing to do with each other, but I understand that there are differences. Assuming your reference is to this paper? http://www.acoustics.asn.au/conference_proceedings/AAS2008/papers/p47.pdf - from my brief understanding having skimmed the paper, it proves that it is possible to detect channel differences in sinus tones as low as 31.5hz (barely) and at least 40hz.

Yes, that is the paper I linked that no one knew of (otherwise please link where/when cited before). No, you don't understand it. It's not "channel differences", its "spatial sensation", as in yes with non mono signal, no/none with mono signal.

In a dual mono setup, I maintain that the loss of laterialisation will be low.

Proving you clearly don't understand it. That's ok. Other than those who like classical, concert halls type spatial bass, etc. it should not be a concern.
It's Einstein's definition of madness, but here goes again https://www.audiosciencereview.com/...eo-sub-vs-dual-mono.43767/page-2#post-1555765

 

[Joaquinín]

Same here. I prefer stereo subs for 2 channel content, at least when you also physically locate the subs appropriately right and left. I currently have four 8" subs in my office, with two in front as right and left under the mains, and the other two in back as right and left, as seen in my office layout down below. Before going to 4 subs, I was running two subs in stereo. At that time, I tried dual mono subs and found much preferred stereo subs.

I figured that might change with 4 subs, so I started out trying to do mono again. It took a lot of fuss with REW/MSO/Dirac, but I eventually got a good quad mono setup that measured objectively well and sounded subjectively good. However, after listening to the mono sub setup for over a month, I reconfigured the four subs for stereo, and now I'm much happier with it. For me, stereo subs provide a better sense of channel separation and more spaciousness than mono subs, at least in my configuration. There is also far more deep stereo bass than people think, especially outside of pop/country music.

View attachment 278714

Isn't DLBC just mono for all the subwoofers? I don't see any options for stereo bass management in DLBC. Am I wrong?

 

[anotherhobby]

Isn't DLBC just mono for all the subwoofers? I don't see any options for stereo bass management in DLBC. Am I wrong?

It might be, but I'm not familiar with DLBC. The miniDSP Flex that I use only has Dirac Live on it, which is 2 channel only. DL just see's 2 speakers and doesn't even know subs exist; so crossovers, delays, and routing must all be set on your own before your run calibration.

 

[Joaquinín]

It might be, but I'm not familiar with DLBC. The miniDSP Flex that I use only has Dirac Live on it, which is 2 channel only. DL just see's 2 speakers and doesn't even know subs exist; so crossovers, delays, and routing must all be set on your own before your run calibration.

Ok. I´ll stay with DLBC then, as it solves those details so well.

 

[sigbergaudio]

Yes, that is the paper I linked that no one knew of (otherwise please link where/when cited before). No, you don't understand it. It's not "channel differences", its "spatial sensation", as in yes with non mono signal, no/none with mono signal.

Proving you clearly don't understand it. That's ok. Other than those who like classical, concert halls type spatial bass, etc. it should not be a concern.
It's Einstein's definition of madness, but here goes again https://www.audiosciencereview.com/...eo-sub-vs-dual-mono.43767/page-2#post-1555765

It feels a bit like you have decided that I don't understand without really knowing if that is a fact. It's not very helpful to repeat that I don't understand. I would also like to point out that "not agreeing" and "not understanding" are two different things.

I suspect this is not a case of me not understanding these concepts, but about us using words that we don't both understand to mean the same.

First it was not localization but lateralisation. I am not a native English speakers, so I will readily admit that "lateralisation" was a new term to me, that I assumed basically meant being able to locate / place sound sources, but it appears it's when "the listener determines the location of sounds, presented through headphones, in their head" (https://www.sciencedirect.com/topics/medicine-and-dentistry/sound-localization#:~:text=Sound localization refers to the,Musiek and Chermak, 2015)

If that is the case, you are right that I do not understand what lateralisation has to do with a discussion about subwoofers.

Now it's not lateralisation, but spatial sensation: "Spatial audio is a way of creating sound in 360 degrees around a listener. Sound can come from any place in a sphere" - Do we agree about this definition? If we do, I have not experienced that the ability to reproduce a spatial sensation (like the low frequency content assisting to create the illusion of a concert hall, church or similar sensory illusions of being within a large space) is reduced in dual mono configurations. This is in fact one of the particular strengths of the audio systems I design (our cardioid design especially), and my experience is that it is typically not meaningfully diminished when a system is switched from stereo to dual mono. So this is possible to achieve in a way where it will definitely work in a dual mono setup. I will however happily allow for the fact that there may be lots of recordings out there that I'm not aware of that where one will detect significant differences between these configurations. Can you perhaps refer me to some?

 

[FrankW]

am not a native English speakers,

Understand.

so I will readily admit that "lateralisation" was a new term to me, that I assumed basically meant being able to locate / place sound sources,

No, that is localization, ability to locate approximately where.

If that is the case, you are right that I do not understand what lateralisation has to do with a discussion about subwoofers.

Lateralisation, as it relates to subwoofers, is a spatial sensation, more like a "wide" vs "narrow", start reading from here https://www.audiosciencereview.com/...than-digital-right.37657/page-20#post-1513869
Regardless of your language, it may be a very difficult concept for those who don't frequent classical concert halls and have experienced the "bass around you" spatial sensation that Dr Greisinger refers to in his papers (like JJ, arguing against monophonic bass...for classical etc). There is no such thing with mono bass, dual mono subs, etc.
Actually, if you read the other paper I have now linked multiple times, the cardioid bass you design is actually helpful here, even if you weren't aware!
Music? Just about any classical track >1980s?