2-Channel Subwoofer Integration

[a.wayne]

Hahaha ,

so-“your “ experience is some loudspeakers are like integrated amplifiers .


You still listening with your milky and a pacifier ..



Regards

 

[nc42acc]

I just stuck my SB13 Ultra in the middle between the speakers. Sounds great, must have got lucky.

 

[LenWhite]

I have read >1 subwoofer does help with room modes.

Perhaps because I listen in an acoustically designed room, from my center listening position I'm hearing the bass exactly where I heard it prior to the single F212 via the CR1. When an instrument with low bass is playing, it's location is where it is in the recording, except more authoritative and palpable. And frequencies >90Hz have improved by virtue of the reduced vibration in the main speakers and the amplifier relieved of low bass demands.

 

[rbbert]

Location cues for what is thought to be low bass are actually due to higher harmonics, not the low bass primary frequency. So, yes, the "imaging" will be the same no matter how many subs are in use. See AJ's link several posts above; this has certainly been well known for more than 35 years.

 

[chops]

My experience with subwoofers is as follows:
1. Two subs are better than one. Always.

3. Properly integrating sub/subs with the mains require technical knowledge and patience. The reality is that many folks don’t have either and the results are poor! (But they don’t know because they only rely on their ears!)

4. Don’t listen to the “purists” who complain about the extra box; more than likely those are the same guys who only rely on their ears - see above.

5. Think of speakers as if they were electronic components. An integrated amp works in many situations but separates (preamp, stereo amp or mono amps) can always work/integrate better. Getting a speaker to do everything with just one box is the equivalent of having an integrated amplifier.

1. Agreed

3. Agreed

4. Disagree... Maybe for some, but not all. I have several stand-alone DSP's, active crossovers, RTA's, software and knowledge to get the job done right, and yet after plenty of measuring, testing, tuning, etc, etc, it sounds good UNTIL one day you remove it from the system and go back to the "purist" version of the system only to realize that that "extra box" was literally sucking all of the life and dynamics out of the music/system.

5. No, it simply doesn't work that way.

 

[chops]

1. Not every loudspeaker benefit from powered subs ..!

3. Integrating subs , into room and speakers be it active or passive is a very complex deal and IMO not easily discuss in such shallow discussions, your above over simplifications is just that
In no way does one path fits all situations and sadly we all have to use our ears to listen regardless of how many test instruments are used ..

Balancing the audio scale can be very elusive ...!!!!



Regards

1. Disagree... Every loudspeaker benefits from subwoofers, because it's the room that you're supposed to be optimizing with the subs which in turn makes whatever loudspeakers you have perform better. In fact, loudspeakers that extend down further benefit even more with subwoofers due to the more drastic nulls and peaks that they are creating on their own. The subs come in to help reduce and sometimes mostly eliminate some or most of those nulls and peaks.

3. Agreed.

 

[AJ Soundfield]

Location cues for what is thought to be low bass are actually due to higher harmonics, not the low bass primary frequency. So, yes, the "imaging" will be the same no matter how many subs are in use. See AJ's link several posts above; this has certainly been well known for more than 35 years.

No, the studies cited show the complete opposite. Even in the summaries linked. There is no "imaging" with a single sub, because by definition, that's mono. Mono/single sub completely eliminates spatial rendering which exists in stereo recordings with decorrelated LF info, so not pop music, but classical, jazz etc.
If an audiophile listens primarily to pop/electronic music, mono/1 sub is fine. For classical/acoustic music fans, not so much.

 

[Hear Here]

Even in the summaries linked. There is no "imaging" with a single sub, because by definition, that's mono. Mono/single sub completely eliminates spatial rendering which exists in stereo recordings with decorrelated LF info, so not pop music, but classical, jazz etc.
QUOTE]

I think you are fundamentally wrong here, I'm sorry to say. The human ear cannot identify the direction a very low frequency sound is coming from, so "imaging" of bass is pretty much irrelevant, however many subs you stuff the room with.

Imaging is generated solely by higher frequencies where the human ear and the brain that processes sound signals can identify with amazing accuracy where the source of the sound is coming from.

I'm an anti-subwoofer believer (I prefer full-range main speakers only), but I've heard very convincing sound with very fine imaging from a pair of LS 3/5As and a single sub placed virtually anywhere in the room provided that position is sympathetic to the room's acoustics. But of course the XO frequency has to be fairly low.

 

[Jim Smith]

Not wanting to get in unwinnable arguments - that I have never seen where one person changed the mind of the other in an online feud - I have refrained from comments on this thread, even though I've written numerous articles - such as the 7-part Subwoofery series in Copper e-mag, as well as having voiced hundreds of systems to rooms with subs.

I do remember one system/room - actually an AudioShark member - whose room & system didn't appear to particularly benefit from subs, but that's a tiny percentage, way less than 1 percent.

For me and my clients, I use a not-often-used-elsewhere statement to describe the benefits of a pair of subs - "It's not so much about the bass, as it is about the space." By that I mean the enhanced spatial quality, the increased sense of presence - a tactile reach-out-and-touch it quality that when set-up properly to do so, dramatically increases the ME Factor - Musical Engagement.

And yes, I could present differing arguments on the bass quality, which is 100% among "Best of...." when heard here in my RoomPlay Reference demo room, but to what end?

Please continue on with each of your positions - good luck getting even one person to change his mind...

opcorn:

 

[nicoff]

1. Agreed

3. Agreed

4. Disagree... Maybe for some, but not all. I have several stand-alone DSP's, active crossovers, RTA's, software and knowledge to get the job done right, and yet after plenty of measuring, testing, tuning, etc, etc, it sounds good UNTIL one day you remove it from the system and go back to the "purist" version of the system only to realize that that "extra box" was literally sucking all of the life and dynamics out of the music/system.

5. No, it simply doesn't work that way.

The flagship models for many of the high end speaker manufacturers include multiple towers. In other words, the manufacturer, when designing their ‘ultimate’ speaker, opted for multiple towers and/or boxes independent from the two main speakers because they must have felt that they could not accomplish what they wanted with just two towers. MBL Extreme (4 towers), Avant-garde Trio (separate bass array) are just two examples. That’s why I made the analogy of “integrated” (2 towers) vs “separates” (more than two towers). I know that this is a simplified view.

 

[AJ Soundfield]

I think you are fundamentally wrong here, I'm sorry to say.

You can think whatever you wish, lacking understanding of the small sample of scientific, peer reviewed factual evidence presented supporting my position, not opinion.
And as always on audio forums, you have confused localization with lateralization, which you've most likely never heard of, much less understand, unlike the scientists conducting those confirmation tests. Not the same thing.
I realize it's futility linking actual science as above, supporting facts vs opinions, but here goes anyway
The effects of acoustical treatment on lateralization of low-frequency sources - NASA/ADS
I'm sure most audiophiles are satisfied with mono correlated bass with the music they listen to, but having been in enough classical concert venues, non-audiophiles are not. So as always, YMMV.
Btw, the use of gradient (velocity or combination) LF sources is as good if not better than the treatment used above.

cheers,

AJ

 

[Mike]

Even in the summaries linked. There is no "imaging" with a single sub, because by definition, that's mono. Mono/single sub completely eliminates spatial rendering which exists in stereo recordings with decorrelated LF info, so not pop music, but classical, jazz etc.
QUOTE]

I think you are fundamentally wrong here, I'm sorry to say. The human ear cannot identify the direction a very low frequency sound is coming from, so "imaging" of bass is pretty much irrelevant, however many subs you stuff the room with.

Imaging is generated solely by higher frequencies where the human ear and the brain that processes sound signals can identify with amazing accuracy where the source of the sound is coming from.

I'm an anti-subwoofer believer (I prefer full-range main speakers only), but I've heard very convincing sound with very fine imaging from a pair of LS 3/5As and a single sub placed virtually anywhere in the room provided that position is sympathetic to the room's acoustics. But of course the XO frequency has to be fairly low.

True story, I have a friend with a really nice system. AJ knows him too. He has one sub, when I listen, I can immediately hear it and it’s all out of whack. I asked him to get a second, but he’s literally deaf in one ear (and I jokingly tell him he can’t hear out of the other one! [emoji6])

The point is: two subs (or more) or none. Four/six ideally. Never 1/3/5.

IMHO.


Sent from my iPhone using Tapatalk Pro

 

[a.wayne]

The flagship models for many of the high end speaker manufacturers include multiple towers. In other words, the manufacturer, when designing their ‘ultimate’ speaker, opted for multiple towers and/or boxes independent from the two main speakers because they must have felt that they could not accomplish what they wanted with just two towers. MBL Extreme (4 towers), Avant-garde Trio (separate bass array) are just two examples. That’s why I made the analogy of “integrated” (2 towers) vs “separates” (more than two towers). I know that this is a simplified view.

Very ..!

 

[a.wayne]

Adding multiple subs ( We all can agree 2 min is best ) solves one issue and crates another not all speakers benefit from adding subs , but one may prefer what subs bring to the table in body , tone and power not present in recordings but add to the overall Pleasure of listening for that individual, this is totally different from systems designed to be used as 4 towers setups .

Systems designed to be used as 4 towers tend to have their bass towers matched to the mains which are capable of a proper spectral balance for such powerful woofers ..

Adding 5 subs to a simple 1” dome 4 inch midrange setup will not have a proper balance spectrally or dynamically it cant , there is no way for the small mid/twt assembly to match the dynamic Power of the added subs, in this situation subs are setup subpar for balance , this is when we get into the ridiculous 30 hz xover points ( poor hand off ) or diminished gain situation until sale ensue ..!


1. A properly designed and balanced loudspeaker will not benefit from additional subs , this doesnt mean someone wont prefer them with subs , but on well recorded non fictional music it will not sound balanced and exhibit poor timbre and attack ..

2. Properly designed 4 towers with multiple subs will have the appropriate mid/twt design to take advantage so should not lose attack, timbre or speed on music material , this is IMO the ultimate way to design a SOTA system no one box will best this arrangement when done correctly ..



Regards

 

[a.wayne]

1. Disagree... Every loudspeaker benefits from subwoofers, because it's the room that you're supposed to be optimizing with the subs which in turn makes whatever loudspeakers you have perform better. In fact, loudspeakers that extend down further benefit even more with subwoofers due to the more drastic nulls and peaks that they are creating on their own. The subs come in to help reduce and sometimes mostly eliminate some or most of those nulls and peaks.

3. Agreed.

Loudspeaker benefits or the room ..,

 

[u-sound]

overall an excellent post.
can you explain a little more what you do mean with ridiculous 30hz xo points?

for balance , this is when we get into the ridiculous 30 hz xover points ( poor hand off ) or diminished gain situation until sale ensue ..!

 

[ACHiPo]

Not wanting to get in unwinnable arguments - that I have never seen where one person changed the mind of the other in an online feud -

- "It's not so much about the bass, as it is about the space." By that I mean the enhanced spatial quality, the increased sense of presence - a tactile reach-out-and-touch it quality that when set-up properly to do so, dramatically increases the ME Factor - Musical Engagement.

:

Jim,
That is spot on with my experience (both feuds and subs). I started with two subs for better bass, but what I discovered especially after adding a third (dual) is the sense of space, of venue. The acoustic treatment and EVPs have a more profound impact on bass, but the subs really flesh out the music and increase emotional enjoyment.
Evan

 

[rbbert]

No, the studies cited show the complete opposite. Even in the summaries linked. There is no "imaging" with a single sub, because by definition, that's mono. Mono/single sub completely eliminates spatial rendering which exists in stereo recordings with decorrelated LF info, so not pop music, but classical, jazz etc.
If an audiophile listens primarily to pop/electronic music, mono/1 sub is fine. For classical/acoustic music fans, not so much.

Any chance you could post the entire article you referenced, or if that violates copyright at least some relevant quotes? The introduction on the first page suggests that if the main speakers have enough low frequency response there will be spatial imaging, even if only one sub is used for the lowest 1/2 - 1 octave (~ 20-35 Hz)

 

[AJ Soundfield]

Any chance you could post the entire article you referenced, or if that violates copyright at least some relevant quotes?

Not sure which of the 4 links you're referring to. The (Rhonda Wilson) Meridian one is by far the most comprehensive, an overview of 45 papers.

4 CONCLUSION
The standard 5.1 configuration has two fundamental weaknesses at low frequencies: a) no opportunity to
transmit low frequency spatial information present in a recording, and b) limited opportunity to control room
modes. Some control of room modes can be achieved by experimenting with location in the room or by modal equalisation.
Use of a mono signal, replayed via multiple subwoofers with suitable signal processing, allows one to present more uniform bass over a listening area. However there is still no opportunity to present spatial information. Use of two subwoofers placed to the left and right of the listener and playing left and right LF signals allows presentation of spatial information.
The system which has been studied least in the literature is the one where all 5 (or 7) main channel loudspeakers have good low frequency response. This system in combination with appropriate signal processing would seem to present the greatest
opportunity for controlling room modes, using both modal equalisation and the interaction of multiple drive units, and presenting spatial information.

The introduction on the first page suggests that if the main speakers have enough low frequency response there will be spatial imaging, even if only one sub is used for the lowest 1/2 - 1 octave (~ 20-35 Hz)

That's why I stated earlier "mono" <40-50hz is fine. Most listening/living rooms cannot support lateralization that low. But 80-90Hz is way too high...for uncorrelated bass material/modern classical etc. All the caveats apply. Btw, the last reference above by Rhonda is to a PSR type system. Definitely no mono bass.

 

[JoeESP9]

This thread is making me pay more attention to this site.

I've been running dual DIY 12" TL subs for more than 20 years. When I started with the dual subs there wasn't anywhere/anyone to discuss the entire subwoofer thing. Consequently I've learned mostly by trial error and measurements what actually sounds best to me.

Since the later 1970's I've used measurements to set up and adjust my system for flatter in room response. Since the middle 1990's I've had a dedicated acoustically treated room. Way back then (1970's), I used an LP with test tones a Rat Shack SPL meter and a 12 band linear equalizer. Nowadays I use REW, a calibrated mic and a laptop to measure my in room response. A 12 band DSP is then used to adjust the sound. Once this is done the DSP is set and forgotten.

I use an electronic crossover to feed main and sub amps. My subs are placed asymmetrically and run in stereo.

Some of the things I've learned through trial and error are:

In a symmetrical room asymmetrically placed subs work better and need less "correction".

Subs run in stereo sound better than in mono. This is so even with LP's which typically have all frequencies below 100Hz in mono.

Once a room has been set up to sound flat different sources do not need different settings.

Bass that's flat to the lower 20Hz area can cause some weird vibrations you never knew were there.

Foundation bass brings more of the room/hall sound and helps with the soundstage.

Removing low bass from the mains allows them to play louder clearer and requires less power to do so.

The one universal truth about subs I've learned is, just about every speaker including so called "full range" speakers will benefit from the addition of a subwoofer (two is better). The only real exceptions are usually relatively expensive and more often than not include their own powered subwoofers or sub towers.

As for the original question:
The only way to be sure a sub(s) is set up properly is to use measurements. As to whether the results are satisfactory to you is for you to decide.

IME the flatter my in room response the closer my stereo sounds to live and the better it sounds to me. What it boils down to, is when I come home from hearing live unamplified (orchestral) music I'm not disappointed when I play some music.