Yes, but the authors are specifically talking about cardioid subwoofers.It is very interesting indeed, glad ya took the time to read it.
And agree, 5 full range can be pricey (I know, paying for such a system now!), but worth it! Will in fact have 5x full range cardioid towers
Soundfield does full range cardioid, as does I believe GGNTKT, Gethain, and Genelec. May be others I am not aware of.
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How to find what music has stereo bass (with EasyEffects)
- Thread starter bachatero
- Start date
Well, you only want cardioid down to approx 40Hz, after which the benefit becomes negligible. Monopole subs take over at 40 and below. Which is exactly how my system will be setup. Please see my “end game quest” thread for more details
TheZebraKilledDarwin
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It seems that after years this topic is finally getting some traction which is good.
I think that with the enveloping effect, attention must be paid to whether it's a desired or undesired effect (depending on on which channels it occurs).
I come from the production side and "stereo bass" - or more specific: uncorrelated bass - is a given in surround production. IMO it plays a big role for an impressive theatrical sound (more later).
For anyone interested I made a small Dolby HD test file of 40 seconds (attached to a black-screen-video) so that everybody with a 7.1 system can check, if, and at which crossover frequency, he thinks an enveloping effect kicks in in their setup:
The test file contains one channel of a stereo mix routed to Lrs (left rear surr.) or Rrs.
All other channels are muted.
The intention is to make it easier to hear at which crossover frequency one might experience a kind of enveloping effect: if/when you notice that the lows of the channel spread out.
For the test I recommend to set the XO frequencies of all speakers to the same frequency in the AVR.
I hear the following:
As XO increases, at some point it starts to drag the lower instruments more into the room, the perceived "weight" at the the location of the speaker becomes lighter, while the bass seems to spread more into the room. It reminds me a bit of image smearing of a phantom sound source with a sub too far to one side.
If you also can hear it with your setup, I would like to draw the following conclusions from this:
1. A kind of enveloping effect is noticeable even with just one channel due to a (too high) XO and sub placement too far away from the speaker.
2. Therefore we must be even more careful with dual mono bass reproduction with two subwoofers. A perceived wider stereo base could result in a deteriorated phantom center if the subs are not placed close to the speakers.
If this "stereo-sub" thing is done on the left and right channels, if they carry phantom center signals, and the subs are placed far off, the phantom center could suffer massively.
3. On the other hand, if it is done in a multi-channel setup, on the left and right channels (or on LR upmixed stereo after C-channel extraction), or done with the surround channels, and if the center has its own dedicated subwoofer, the out-of-phase bass components, which are present in the (surround or upmixed stereo) mix should be perceived as if the width/depth of these channels was magnified (IMO that's why good multichannel setups in studios and dub stages do not sum bass to mono - stereo width of low f is important - highpassing thunder, wind, atmos @80 Hz and monoizing it for theatrical soundtracks?; TV productions with an ITU 5.1 setup handle things differently though).
Btw everyone should be familiar with this "stereo bass" effect even without knowing it consciously:
I would describe it as one of the beautiful effects in large theatres. Especially after longer periods of dialogue, which is very localized and center focused, when a massive, deep and wide width in the (fullrange) surround field is setting in. The contrast from the mono center to bassy width and depth just sounds cool.
I think that with the enveloping effect, attention must be paid to whether it's a desired or undesired effect (depending on on which channels it occurs).
I come from the production side and "stereo bass" - or more specific: uncorrelated bass - is a given in surround production. IMO it plays a big role for an impressive theatrical sound (more later).
For anyone interested I made a small Dolby HD test file of 40 seconds (attached to a black-screen-video) so that everybody with a 7.1 system can check, if, and at which crossover frequency, he thinks an enveloping effect kicks in in their setup:
The test file contains one channel of a stereo mix routed to Lrs (left rear surr.) or Rrs.
All other channels are muted.
The intention is to make it easier to hear at which crossover frequency one might experience a kind of enveloping effect: if/when you notice that the lows of the channel spread out.
For the test I recommend to set the XO frequencies of all speakers to the same frequency in the AVR.
I hear the following:
As XO increases, at some point it starts to drag the lower instruments more into the room, the perceived "weight" at the the location of the speaker becomes lighter, while the bass seems to spread more into the room. It reminds me a bit of image smearing of a phantom sound source with a sub too far to one side.
If you also can hear it with your setup, I would like to draw the following conclusions from this:
1. A kind of enveloping effect is noticeable even with just one channel due to a (too high) XO and sub placement too far away from the speaker.
2. Therefore we must be even more careful with dual mono bass reproduction with two subwoofers. A perceived wider stereo base could result in a deteriorated phantom center if the subs are not placed close to the speakers.
If this "stereo-sub" thing is done on the left and right channels, if they carry phantom center signals, and the subs are placed far off, the phantom center could suffer massively.
3. On the other hand, if it is done in a multi-channel setup, on the left and right channels (or on LR upmixed stereo after C-channel extraction), or done with the surround channels, and if the center has its own dedicated subwoofer, the out-of-phase bass components, which are present in the (surround or upmixed stereo) mix should be perceived as if the width/depth of these channels was magnified (IMO that's why good multichannel setups in studios and dub stages do not sum bass to mono - stereo width of low f is important - highpassing thunder, wind, atmos @80 Hz and monoizing it for theatrical soundtracks?; TV productions with an ITU 5.1 setup handle things differently though).
Btw everyone should be familiar with this "stereo bass" effect even without knowing it consciously:
I would describe it as one of the beautiful effects in large theatres. Especially after longer periods of dialogue, which is very localized and center focused, when a massive, deep and wide width in the (fullrange) surround field is setting in. The contrast from the mono center to bassy width and depth just sounds cool.
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Sokel
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I said the same thing time and time again:
A baritone's voice at its lows through a system of high-crossed mono lows feels like is coming from a mouth the size of a cave.
"Proportions" is the key word.
TheZebraKilledDarwin
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Don't tell consumers with monoized 80 Hz XO...
Ls/Rs:
(MI:8)
10s video:
Ls/Rs:
(MI:8)
10s video:
Is it really?
I thought LOTS of modern recordings keep L/R rather than summing, far below 80Hz?
> There are some good reasons for mono (centered) bass. The main thing is that the "average stereo" NEEDS both woofers for the most & lowest bass possible.
I don't follow. With co-located L/R "stacks" there is no requirement to avoid overlapping outputs from multiple drivers
whether the reproduction system sums the bottom LF contents of the signals or keeps them separate.
right?
It's another "benefit" of vinyl that under 200Hz (is it?) recordings are mono.
I have two subs on the floor each under my main speakers -that's potentially double the wattage. Which is nice.
Allow me to recap points made long ago.
1) Mains should go down to 40Hz.
2) Mains should go down to 40Hz.
3) Mains should go down to 40Hz.
And, of course, the LF radiator should be co-located with the rest of the speaker.
Now, the "subwoofer channel" in theatres was never EVER supposed to be bass support, it was the LFE, or LOW FREQUENCY EFFECTS channel. Think "earthquake".
Despite the various claims made, and misinterpretations of older work, there are some clear issues.
1) You can not sense DIRECTION below 90Hz or so, give or take.
2) You CAN sense "width" down to 40Hz or so, give or take.
3) Having 2 subwoofers next to each other provides a bit more radiated energy. 3dB rise in SPL under nearly all situations. Remember that 10dB is "twice as loud", so 2 subs are NOT very much LOUDER at all, and LOUDNESS is what you hear.
On LP's, bass was mono-ed because of the difficulties of cutting the actual LP, and the tracing of the L-R channel, which is "up and down". It's hard to get that groove to have a height above the vinyl surface, so L-R is heavily controlled when cutting the LP masters. This wasn't about anything beyond the physical limitations of the LP mechanics. This was excused with the 90 Hz lower limit established by the older work that shows that direction wasn't a thing below 90Hz.
In the modern day, there is NO EXCUSE for this. Yes, some electronic material comes in like that, but in fact how to fix that is well understood, just almost never used. So, especially with "immersive" content THERE SHOULD BE NO SUBWOOFER AND NO SUBWOOFER CHANNEL until you get below 40Hz.
All of this is pretty easily proven with simple test signals, and simply measured with proper measurements of good acoustic venues. This does not seem to matter a bit to the general production chain.
1) Mains should go down to 40Hz.
2) Mains should go down to 40Hz.
3) Mains should go down to 40Hz.
And, of course, the LF radiator should be co-located with the rest of the speaker.
Now, the "subwoofer channel" in theatres was never EVER supposed to be bass support, it was the LFE, or LOW FREQUENCY EFFECTS channel. Think "earthquake".
Despite the various claims made, and misinterpretations of older work, there are some clear issues.
1) You can not sense DIRECTION below 90Hz or so, give or take.
2) You CAN sense "width" down to 40Hz or so, give or take.
3) Having 2 subwoofers next to each other provides a bit more radiated energy. 3dB rise in SPL under nearly all situations. Remember that 10dB is "twice as loud", so 2 subs are NOT very much LOUDER at all, and LOUDNESS is what you hear.
On LP's, bass was mono-ed because of the difficulties of cutting the actual LP, and the tracing of the L-R channel, which is "up and down". It's hard to get that groove to have a height above the vinyl surface, so L-R is heavily controlled when cutting the LP masters. This wasn't about anything beyond the physical limitations of the LP mechanics. This was excused with the 90 Hz lower limit established by the older work that shows that direction wasn't a thing below 90Hz.
In the modern day, there is NO EXCUSE for this. Yes, some electronic material comes in like that, but in fact how to fix that is well understood, just almost never used. So, especially with "immersive" content THERE SHOULD BE NO SUBWOOFER AND NO SUBWOOFER CHANNEL until you get below 40Hz.
All of this is pretty easily proven with simple test signals, and simply measured with proper measurements of good acoustic venues. This does not seem to matter a bit to the general production chain.
I don’t really agree with the idea that a second subwoofer only gives “+3 dB and that’s it”, because that framing misses what is actually happening in a real room and, more importantly, what the listener perceives.
Yes, from a strictly textbook point of view, if you take two coherent, perfectly correlated point sources in free field, you end up with roughly +3 dB SPL. But loudspeaker systems in domestic rooms are not point sources in free field, and bass reproduction is very much not a simple single-number SPL story.
What actually changes when you add a second woofer is radiating area and coupling to the air and room, and that is where the subjective “scale” of bass comes from. Doubling cone area does not just “add 3 dB” in perception it changes:
air volume displacement capability (much lower distortion for the same SPL),headroom before compression, modal excitation distribution in the room and often the spatial impression of low-frequency energy
That last point is often ignored in these discussions. Even if localisation below ~80–90 Hz is weak in terms of direction, the distribution of low-frequency energy in the room absolutely affects perceived width, envelopment and “size” of the soundstage.
So while the SPL arithmetic is technically correct in a narrow sense, it is not a good description of what a listener actually experiences.
On the historical point: I also agree that older programme material and vinyl mastering constraints strongly influenced the tendency to mono the bass. That was largely a mechanical necessity, not an aesthetic truth about how low frequencies “should” be handled. Modern production has no such limitation, and we now have the tools (multiple subs, bass management, DSP) to distribute low-frequency energy far more intelligently.
Regarding modern content like Iris SelloRekt – LA Dreams: in cases where the mix genuinely extends deep and demands headroom, adding additional low-frequency radiating area (whether via multiple subs or properly integrated bass systems) is not about “making it louder”, but about maintaining linearity and reducing compression/distortion at realistic playback levels.
So I would frame it differently:
It’s not “a second sub = +3 dB and nothing else”, but rather “a second sub = significantly more displacement, better room interaction options, and potentially lower distortion for the same target SPL”, which is a much more meaningful improvement than the simple summation figure suggests.
Yes, from a strictly textbook point of view, if you take two coherent, perfectly correlated point sources in free field, you end up with roughly +3 dB SPL. But loudspeaker systems in domestic rooms are not point sources in free field, and bass reproduction is very much not a simple single-number SPL story.
What actually changes when you add a second woofer is radiating area and coupling to the air and room, and that is where the subjective “scale” of bass comes from. Doubling cone area does not just “add 3 dB” in perception it changes:
air volume displacement capability (much lower distortion for the same SPL),headroom before compression, modal excitation distribution in the room and often the spatial impression of low-frequency energy
That last point is often ignored in these discussions. Even if localisation below ~80–90 Hz is weak in terms of direction, the distribution of low-frequency energy in the room absolutely affects perceived width, envelopment and “size” of the soundstage.
So while the SPL arithmetic is technically correct in a narrow sense, it is not a good description of what a listener actually experiences.
On the historical point: I also agree that older programme material and vinyl mastering constraints strongly influenced the tendency to mono the bass. That was largely a mechanical necessity, not an aesthetic truth about how low frequencies “should” be handled. Modern production has no such limitation, and we now have the tools (multiple subs, bass management, DSP) to distribute low-frequency energy far more intelligently.
Regarding modern content like Iris SelloRekt – LA Dreams: in cases where the mix genuinely extends deep and demands headroom, adding additional low-frequency radiating area (whether via multiple subs or properly integrated bass systems) is not about “making it louder”, but about maintaining linearity and reducing compression/distortion at realistic playback levels.
So I would frame it differently:
It’s not “a second sub = +3 dB and nothing else”, but rather “a second sub = significantly more displacement, better room interaction options, and potentially lower distortion for the same target SPL”, which is a much more meaningful improvement than the simple summation figure suggests.
You double the displacement (assuming identical subs). Again, that's 3dB. You might get better room interactions, you might get worse. Now, I'm not saying you should stick with1 sub, if you MUST have subs, have one PER CHANNEL, co-located with the main.
Yes, there are room interaction problems. Always.
And it must be nice to think everyone "must" be able to use a single multi-way pair that can output matched SPL right down to 40Hz.
For people living from paychecks, and/or in smaller living spaces that simply is not an option.
My main pair start to give out above 150Hz, so I need to stack separate boxen, obviously maintaining stereo at least one box lower.
I will end up getting there (as low as possible matching mains SPL) through multiple subs per stack
and will test - both outdoors and in various spaces - whether summing the signal sent to the bottom sub to mono is better or not.
If not, then I may need to add more non co-located mono units to allow free placement tackling room issues, when the system is working in larger spaces, say over 100 sqft
If I use DSP, it seems very different approaches are required for the mono boxen at the low end, vs the ones in the stereo stack playing over 60-80Hz.
For people living from paychecks, and/or in smaller living spaces that simply is not an option.
My main pair start to give out above 150Hz, so I need to stack separate boxen, obviously maintaining stereo at least one box lower.
I will end up getting there (as low as possible matching mains SPL) through multiple subs per stack
and will test - both outdoors and in various spaces - whether summing the signal sent to the bottom sub to mono is better or not.
If not, then I may need to add more non co-located mono units to allow free placement tackling room issues, when the system is working in larger spaces, say over 100 sqft
If I use DSP, it seems very different approaches are required for the mono boxen at the low end, vs the ones in the stereo stack playing over 60-80Hz.
I'm simply saying what is necessary to get it right. Unless you need ear-harming levels, it's not that hard, either. I do, however, agree that a box 6"x4"x7" won't do it very well.
You are free to cite your evidence. Go to it.
My own system ended up taking a somewhat similar direction, although mainly for room integration reasons. I use Canton Karat 300 mains, each sitting directly on top of an HSU VTF-15H with aligned front baffles. The mains are crossed at 60 Hz LR4 and the subs at 80 Hz LR4.
Rather than fully summing bass to mono, each front channel primarily feeds its local sub with reduced crossfeed to the opposite sub, while the center contributes to both. The left sub is a VTF-15H Mk1, the right a Mk2. Through REW optimization I ended up with different delays and the left sub polarity inverted. In my room, the Mk2 acts more as the deep-bass foundation while the Mk1 contributes more to upper-bass integration and smoothness.
Most of the improvement came from placement, routing, timing, polarity, and crossover optimization before applying only modest EQ. Subjectively, this preserved front-stage attachment better than the fully summed bass-management approaches I had tried previously.
Rather than fully summing bass to mono, each front channel primarily feeds its local sub with reduced crossfeed to the opposite sub, while the center contributes to both. The left sub is a VTF-15H Mk1, the right a Mk2. Through REW optimization I ended up with different delays and the left sub polarity inverted. In my room, the Mk2 acts more as the deep-bass foundation while the Mk1 contributes more to upper-bass integration and smoothness.
Most of the improvement came from placement, routing, timing, polarity, and crossover optimization before applying only modest EQ. Subjectively, this preserved front-stage attachment better than the fully summed bass-management approaches I had tried previously.
How would one get stereo bass to work well in an average room?
Above the crossover of 80Hz I already have room mode interactions I simply have to accept on a single listening location with 1 subwoofer.
If one has full ranged speakers playing down to 40Hz, how do we manage the bass in the room?
In a rectangular room I could of course position my speakers to battle some room modes, but not all of them.
The same story would apply if I put subwoofers in optimal location in a rectangular room and use the 2 left one for playing the left bass channels and the right for the right bass channels. I would still end up with peaks and null all over the listening locations.
How am I supposed to experience stereo bass in a real world scenario that isn't headphones?
I am aware I don't know what I don't know, this is a serious inquiry as I have never given this much thought and these are simply the first thoughts that spring to mind.
To put into a single sentence, and presuming stereo bass at these frequencies is audible:
How will we make them audible to the listener in an average room?
Edit: I did read the thread, but nowhere does it make clear to me how one would work around these limitations.
Feel free to give me something to RTFM, will read it at my leisure then.
Above the crossover of 80Hz I already have room mode interactions I simply have to accept on a single listening location with 1 subwoofer.
If one has full ranged speakers playing down to 40Hz, how do we manage the bass in the room?
In a rectangular room I could of course position my speakers to battle some room modes, but not all of them.
The same story would apply if I put subwoofers in optimal location in a rectangular room and use the 2 left one for playing the left bass channels and the right for the right bass channels. I would still end up with peaks and null all over the listening locations.
How am I supposed to experience stereo bass in a real world scenario that isn't headphones?
I am aware I don't know what I don't know, this is a serious inquiry as I have never given this much thought and these are simply the first thoughts that spring to mind.
To put into a single sentence, and presuming stereo bass at these frequencies is audible:
How will we make them audible to the listener in an average room?
Edit: I did read the thread, but nowhere does it make clear to me how one would work around these limitations.
Feel free to give me something to RTFM, will read it at my leisure then.
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Room optimization and spatial cues are separate problems. You still need to optimize placement, crossover, delays, and EQ for smooth response, but if some low-frequency spatial information survives the recording and playback chain, preserving it may provide benefits beyond what a fully summed mono approach can. In my case, a fairly large open-plan room made experimentation easier because the modal density is lower and the room is less symmetrical than a small rectangular room.
No, they are the same problem.
From my understanding:
If the bass from the left speaker sounds much louder to you then the bass from the right speaker that will impact spatial ques if stereo bass at these frequencies is relevant in your room.
I truly do not see how it could be otherwise, either stereo effects matter at these frequencies, which means it also matters how loud you hear them at listening location.
Or it does not and we can just sum it to mono and focus our efforts on getting the bass level as good as possible for multiple seats.
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As for experimentation with stereo bass, I'd have to try it on headphones first to see if I the effect is big enough for me to try and test this myself.
I am simply wondering how one could implement this in a room and I might very well be missing something, as this is not my area of expertise.
However, I only learn by asking questions and as noted in my previous post, this raised several for me.
I am simply wondering how one could implement this in a room and I might very well be missing something, as this is not my area of expertise.
However, I only learn by asking questions and as noted in my previous post, this raised several for me.
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