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Subs & Satellites - can it be done right?

sigbergaudio

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Throw in a couple of subwoofers and you will also have a capacity in the lower octaves that few floorstanders can match. So it's simply a different experience.
 

kongwee

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Some will throw subs at odd position because they need to hear the deep note for studio application.
 

Digital_Thor

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Definitely. His work dates back decades, and the diyaudio.com thread dates from 2008, so you see significant evolution/changes in his approach. Rather than looking for a cookbook, I learned from the back and forth, weighing the ideas, supporting scientific explanations, etc.

And yes, high-passing small mains would be required to fully benefit from the increased dynamic capabilities of adding multiple subs. He uses 15" pro woofers, previously vented, now sealed, and we know that pro woofers in relatively small sealed enclosures will lead to a fairly high F3.

My mains have a vented 12" woofer (I have thought a lot about plugging the port if only to see the effects of the lower slope/different phase characteristics, but haven't experimented with it yet). With four subs, I have a low shelf to bring the bass into balance. Combined with parametric eq at my stubborn 35Hz and 78Hz nodes, the mains' woofers are receiving less signal. Last night I played music at a very high level and they moved much less than I was expecting.

"Good and even bass is important, but midbass is also important, and often neglected."

I think so too. I have found that getting < 100hz is fairly straightforward. It is 100-200hz that is the struggle. I have been in a (probably ridiculous, or maybe just insane, per my family, as they listen to seemingly endless signal sweeps) experimental phase with mains placement and sub adjustment over the last week. Thankfully after last night I am back to "leave it alone and listen to music, dummy."

I am nervous about showing images of how it went, but I am pleased with my 100-200hz results, so will show them and they are perhaps illustrative.....please ignore if too much! Or maybe pictures are worth a thousand words? Above 300 hz there are SBIR effects and multiples of room modes. I have convinced my wife to do some radical acoustics work (after I finish the back porch project....), mainly the ceiling and rear wall (currently just treating first reflection points), so this will get better. Right now I am just using PEQs in my RME DAC to fine tune. First two subs are under the mains, fed L/R signals, other two subs fed mono. All 1/48 octave smoothing, 50db scale with target room curve I was shooting for:

Mains:
View attachment 177815

Add sub under left main (blue):

View attachment 177816

Add sub under right main (orange):
View attachment 177817

Clearly, because they are co-located with the mains, their effect on modes isn't huge, though there is some "moving around" and a bit of filling in the nulls.

Add Left rear sub (green):
View attachment 177818

Add fourth sub, R rear. Fascinatingly, the response was good, but there was one deep null at around 120hz remaining. I thought hmmm...let me try moving it a bit. After 3 or 4 moves I ended up with this (pinkish?):

View attachment 177828

Mains only and mains with 4 subs, no EQ:
View attachment 177831

After a bass shelf starting at approx. 85hz (relieving the mains to some degree as described above and 2 bands of parametric EQ in the RME (35 and 78Hz):
View attachment 177832


Sounds pretty good to me at this point. You will notice I don't have huge extension (subs are sealed 10" JBL studio units), but there is good dynamics and "power." I did have a bit of a learning curve to be able to do this in fairly short order, and I am NOT suggesting the OP (or anyone, really) takes this route. It is only for illustrative purposes. With his proposed equipment he will have an easier go of it with their built-in capabilities. I don't know how I could have smoothed > 100hz without higher crossovers.

Now I am praying that when I hit "reply" my formatting will stay and this won't look like a jumbled mess......

Bill
Agree with all you write :)

I have read almost everything I can find on Gedde, Toole, Olive, Winer and all others experiences with the same.
My take is, that you have to pull out the basics off the whole story, not read it to "strictly" .
I used to cross my 3 ways with subwoofers around 80-100Hz. But I did so equally for both subs and woofers - ignoring the fact that sound behaves differently at different frequencies. Subwoofer integration is not acting like the midrange/tweeter integration - same "rules" and guidelines cant be used for both.
I tried all types of filters, slopes, eq and frequencies. But I failed to understand what I just wrote above. Geddes clearly said so, if you just ignore all other talks and confusing discussions. It's actually purely a matte of phase-shift and the relation to each other, when it comes to level and placement.
If you cross between woofers and subs like midrange and tweeter - you might find one little spot, where it works. But you will never have that smooth and even response in a wider area around your listening position.

Woofers should fall off slowly with frequencie - my 2 x 6,5 Purifi in closed 10 liter boxes run to maybe 60Hz - where they actually start to lose level already around 110Hz - they are small, that is the nature law. I apply a 6dB filter aoround 50-60Hz to protect them from crazy low frequencies. But it has to be this low order filter - or else the phase-wrap will screw up the integration.

My 4 subs are crossed at different frequencies from anywhere between 80 and 120Hz - and individually EQ'ed, dealyed, sloped and leveled, to create a total summed and smooth overall response in almost all areas of my room. And I have no boomy or uncontrolled bass anymore. It's actually some of the best bass I have ever heard - anywhere - no matter the price.

Small satellites can work with subwoofers - if you understand their limitations. Lyngdorf make this work, by crossing even higher, to compensate for the 6" driver that simply cant move air like the subwoofer, and their individual placement.
Only picture I could find, with all 4 units:
https://www.carousell.sg/p/lyngdorf-audio-tdai-1120-mh3-bw3-package-1042473299/

I measure within a few dB from low 20' all the way up. I have deviation around the crossover - around 2dB more, if you move your head more than 40cm to each side... but it's actually difficult to detect during music listening.
Even I go to my open kitchen or just around the room, the bass does not go away or suddenly seem much higher. The music stays almost the same, and sounds like it would do with for example talking to a friend in the sofa, while maybe getting up to fetch something in the kitchen... you still understand what is being said and the voice is natural.

I think it will be a compromise with too small speakers and subs - and if it's satellites on stands - I would go 3 way floorstander any day, to get a much easier integrations with subs. The Lyngdorf was pretty cool and well sounding, so it should be possible though.

To the OP - I'm sorry if it went to much OT - but you should definitely try the D&D C8 and then later add 2 subwoofers, when you feel like it's maybe needed and you wish to try out the "fun" on integrating such a setup. We are not talking small satellites here - it has 2 x 8" woofers on the back and tons of digital adjustment.
 

srrxr71

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I think one of the big things people overlook when using small "satellite" speakers and subs is that if you are going to use subs located on the side of the room to eliminate room modes they need to be crossed 80Hz to 100 Hz so the sound is not localized. For best results the satellites need to play flat one octave below the crossover so 40Hz to 50 Hz.... many small satellite can't do this which makes integration with subs difficult. While expensive and "big" using "full / near full" range speakers and a sub is the best way to go and makes integration much easier (possible).
I suppose if one considers a 8331a to be a “satellite” then it could work.
 

Head_Unit

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Something in me tells me 2 big sub boxes with in total 4 times 10-14 inch drivers will please my needs more then the mini D&D box working hard when playing loud AND equalizing backfiring
That voice in your head is called "Isaac Newton" aka "Physics" or "The Laws Of Nature" ;):D
Satellite or floorstanders, everything I've looked at indicates you are unlikely to end up in a happy bass spot with your main speakers. Now, can that be fixed with Audyssey/Dirac/ARC? Maybe to a degree. But even some big floorstanders like our Focal 936 go to to "just" 40 Hz-pretty much enough for most music, but not all, and not low enough for movie explosions and so on. As for room correction being automatic, I can firsthand say my experiences with both Audyssey and ARC have been fairly simple, and resulted in bass sweep tones becoming noticeably smoother. That said, automotive correction I worked with would sometimes think the subwoofer was 20 feet away-algorithms can always be fooled or caught out. It helps the correction to do some experimenting and raw measurements and improve things as much as possible.
 

Head_Unit

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If you're serious about perfect integration, I'd continue the discussion focusing on room treatment rather than electronics
I understand that treating the listening room is first priority.
But as someone may have mentioned, room treatments of any reasonable size don't work at low frequencies (their wavelengths are too long). So low frequency integration becomes a matter of playing a lot with positioning of the satellites and subwoofer(s), the highpass and lowpass frequencies, and/or room correction software.
 

dshreter

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But as someone may have mentioned, room treatments of any reasonable size don't work at low frequencies (their wavelengths are too long). So low frequency integration becomes a matter of playing a lot with positioning of the satellites and subwoofer(s), the highpass and lowpass frequencies, and/or room correction software.
That’s true… but there’s also a lot of sound that isn’t at very low frequencies that can be optimized through room treatment.

My point is that focusing on the speakers when you have KH420, 8c, or other great speakers in consideration, much more meaningful improvement will come from treating the room than the various trade offs between speakers. That’s not to say bass management and integration are unimportant, but to me it is secondary to sorting out the room which may also factor in to constraining which speakers work best for the space too.
 

Head_Unit

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many are concerned about localization of the subs and 80hz seems to be the number people agree on. I also don't think the physics supports this notion. And it is the 90-120hz that I always find the most difficult to get smooth in my room and I don't think I could do it without crossing the subs higher. It is possible I am fooling myself, but I can't locate subs crossed at 120-130hz.
The magical 80 Hz came out of research done at I believe THX. So we can imagine the test conditions are a more ideal room, probably not with a cathedral ceiling or open to a kitchen or with hallways coming out. And high quality transducers.
- If the subwoofer has high distortion at those midbass frequencies, you might well localize the harmonics. Likewise if even a "quality" subwoofer has a forward facing port with a big port resonance. "Cleaner" subs could be harder to localize.
- Where the subs are versus the mains will make a difference-a sub behind you will be easier to localize than one right next to a front speaker.*
- Every person's hearing is different!
I'm curious why you say the physics doesn't support the notion. Not disagreeing, just wondering your reasoning.

*JL Audio actually recommends such a higher crossover in systems with no room correction like Audyssey etc., so their built-in DSP can affect those upper midbass frequencies. https://www.stereophile.com/content/jl-audio-fathom-f110v2-powered-subwoofer-measurements
 

sigbergaudio

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The magical 80 Hz came out of research done at I believe THX. So we can imagine the test conditions are a more ideal room, probably not with a cathedral ceiling or open to a kitchen or with hallways coming out. And high quality transducers.
- If the subwoofer has high distortion at those midbass frequencies, you might well localize the harmonics. Likewise if even a "quality" subwoofer has a forward facing port with a big port resonance. "Cleaner" subs could be harder to localize.
- Where the subs are versus the mains will make a difference-a sub behind you will be easier to localize than one right next to a front speaker.*
- Every person's hearing is different!
I'm curious why you say the physics doesn't support the notion. Not disagreeing, just wondering your reasoning.

*JL Audio actually recommends such a higher crossover in systems with no room correction like Audyssey etc., so their built-in DSP can affect those upper midbass frequencies. https://www.stereophile.com/content/jl-audio-fathom-f110v2-powered-subwoofer-measurements

I suspect it's the other way around. 80hz was chosen because crossing that low will make it hard to localize the sub even in non-ideal conditions. It's a "safe" choice for non-ideal conditions and people with generally low knowledge about how to set up their systems, dropping the subwoofer where it fits or are out of sight.

So in practice you can actually cross higher in many cases.
 

Bill Brown

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- If the subwoofer has high distortion at those midbass frequencies, you might well localize the harmonics. Likewise if even a "quality" subwoofer has a forward facing port with a big port resonance. "Cleaner" subs could be harder to localize.
- Where the subs are versus the mains will make a difference-a sub behind you will be easier to localize than one right next to a front speaker.*
- Every person's hearing is different!
I'm curious why you say the physics doesn't support the notion. Not disagreeing, just wondering your reasoning.
Nice post above @Digital_Thor :)

"If the subwoofer has high distortion at those midbass frequencies, you might well localize the harmonics. Likewise if even a "quality" subwoofer has a forward facing port with a big port resonance. "Cleaner" subs could be harder to localize."

I think that the belief in the perceptibility of distortion in the low frequencies is overemphasized on this site. But yes, what you say is true, if the distortion is high enough to produce perceptive "doubling"the source could be localized. And port resonances, etc.

"Where the subs are versus the mains will make a difference-a sub behind you will be easier to localize than one right next to a front speaker."

I think this is the case only as described above, or (and perhaps more commonly?) buzzes, rattles, cabinet resonances, i.e. mechanical sounds. But not with a theoretically perfect sub.

Re. physics, I have written it in a few areas here, but would refer you to this paper by Geddes. I am no disciple, but he is a very smart dude, and his discussions re. the physics make sense to me at my current level of understanding.


Bill
 

Digital_Thor

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Nice post above @Digital_Thor :)

"If the subwoofer has high distortion at those midbass frequencies, you might well localize the harmonics. Likewise if even a "quality" subwoofer has a forward facing port with a big port resonance. "Cleaner" subs could be harder to localize."

I think that the belief in the perceptibility of distortion in the low frequencies is overemphasized on this site. But yes, what you say is true, if the distortion is high enough to produce perceptive "doubling"the source could be localized. And port resonances, etc.

"Where the subs are versus the mains will make a difference-a sub behind you will be easier to localize than one right next to a front speaker."


I think this is the case only as described above, or (and perhaps more commonly?) buzzes, rattles, cabinet resonances, i.e. mechanical sounds. But not with a theoretically perfect sub.

Re. physics, I have written it in a few areas here, but would refer you to this paper by Geddes. I am no disciple, but he is a very smart dude, and his discussions re. the physics make sense to me at my current level of understanding.


Bill
Cheers mate :)
I think too, that many - myself included sometimes - forget how big a crevice there can be between theory/specs and everyday use(audibility). I went straight for closed subs, because I could get away with an easier design, usually smaller and avoid ports in general. When you sit quietly at home with almost no other noise but a slight hum from the fridge or something... then small details you would never hear with just a few friends around you, - will suddenly be heard a bit easier.
We should strive for no resonances and other distortions, that might alter the sound we hear. But building a solid box, with a strong driver inside, is no longer that impossible. The tuning can be tricky, but you live - and you learn. At least if you want to :D
True that a sub can be heard "wrongly" if there is trouble in the design.... but ain't that the challenge with any sound-box? ;)
 

Head_Unit

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this paper by Geddes
I'll go along with that, as Earl is indeed quite smart and what he says makes sense. One problem: my room opens to a hallway, a kitchen, and french doors to what used to be a sun porch. So not a perfect room at all, and no available corner. I'm pretty sure a lot of people are in the same boat. Fun fact: when Earl was at Ford he offered me a job. I chose to take a job at home in Chicago for more money and not have to move to Detroit. I sometimes wonder what my life would have been like. I probably would have been sent to Brazil, that would have been transformative.
 

Bill Brown

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Very interesting story. It is interesting looking back on the forks in the road of our lives.

While it is definitely unlikely that you could simulate your room(!), I don't think they are terribly realistic in real life. And re. room modes, I suspect your room might be better than those of us with "too square" rooms. I suspect multiple subs and experimentation would give very gratifying results.

Bill
 
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