How many on ASR don't runs subs of any kind.? & why.....

[levimax]

plus the effect from the wrong sound phase that causes 7.5 ms delay to be more appropriate.

Are you sure this cancelation isn't due to the GD? At 40 Hz a group delay of 12.5 ms puts it exactly "out of phase" with the mains driver which would cause cancelation like you are seeing. I had this exact problem with my SVS subs and the large GD causing cancelation at 30 Hz. We are getting off topic but to the OP's question of why no sub's for some people I think difficult (impossible actually with many DSP speaker / DSP sub combinations) integration is one of the main reasons.

 

[alankila]

Are you sure this cancelation isn't due to the GD? At 40 Hz a group delay of 12.5 ms puts it exactly "out of phase" with the mains driver which would cause cancelation like you are seeing. I had this exact problem with my SVS subs and the large GD causing cancelation at 30 Hz. We are getting off topic but to the OP's question of why no sub's for some people I think difficult (impossible actually with many DSP speaker / DSP sub combinations) integration is one of the main reasons.

I have two reasons for disliking subwoofers: firstly, a lot of the time it is going to be a 2.1 system out of necessity and then it is a single source of bass in the room, so room modes are going to be worse because increasing the number of woofers (assuming mono bass, which is reasonable) reduces any resonant behavior. The second are the integration issues that I'm struggling with.

I believe there are no cancellations possible far away from the crossover because Genelec uses quite steep filters for this crossover. And I think 40 Hz is going almost purely out of the subwoofer with no notching possible. Someone else claims that Genelec employs LR8 filters, or at least has measured the slope to be 48 dB/oct (see references at end) which should perform 720 degrees of phase warping which doesn't seem to be happening, but that might well be because I'm also mucking with this by having added my own delay, and that could be making things more confusing for me to understand, now.

Reference 1: glm open source partially reverse engineered module, being discussed here from 2021: https://www.audiosciencereview.com/...ds/python-module-to-manage-genelec-sam.25814/
Some additional information: https://www.diyaudio.com/community/...ind-delay-phase-and-polarity-at-xover.370287/ which happens to discuss LR8 filters at 100 Hz crossover claiming that their intrinsic group delay is 11.8 ms at 100 Hz. If so, that is useful to know. However, what I really would want to know is just how much processing delay a 7370A adds.

I'll have to try to see if I can validate these facts and then make a synthesis. I assumed that excess group delay is a direct measure of the processing delays between the speaker systems, but maybe that is not exactly the truth. Maybe I end up simulating a LR8 crossover at some point and then check how the summed system behaves -- which should have magnitude response of zero, but show 720 degrees of phase warping over the crossover. If I compensate for the low pass side's increased group delay by an added delay worth 1 cycle on the mains, that becomes only 360 degrees, which seems to match what I am seeing. Possibly the sub is in phase after all, and my understanding on the matter is simply too limited.

Maybe some of you have tried this -- can this idea work, or will it cause problems? Or maybe I should simply design all pass filters that can linearize the LR8's phase warping, and only after I've re-established a linear phase across the crossover, try to do anything else?

 

[ZolaIII]

I don't think 22 ms in much to worry about, see below graph for SVS 3000 series subs with over 100 ms of GD. I do agree this is a problem that no one seems to want to talk about when using too small of an enclosure and lots of DSP. The graph is from a test at Audioholics https://www.audioholics.com/subwoofer-reviews/svs-3000
View attachment 443255

It's physics and I whose talking about it a lot. It's progressively worse under the port tuning because it fals sharp (time delay increases). It's taken into account from ISO 226 2012 and future revisions but there is no driver that can follow it with increase in energy (louder) in order to compete for it, however in controled manner in long enough room (8.5~9 m) and still sealed back big sub's you can use room fundamental to offset it. It's not a big issue if phase flips in, under crossing point (you flip it around). You will hear pre ringing (in a bad way) and if you don't then it's not a problem even if there is a tad of it in measurements. You can and need to align impulses (start time point) in order to assure it stays that way after PEQ-ing. Time domain is very real thing! Don't do crossovers in sub bass that's simply insane.

 

[kimmosto]

I think it would be more precise to say that higher order minimum phase crossovers destroy the sound.

Minimum phase total can be done with IIR (your "minimum phase") crossover and phase equalization of input signal i.e. without linear-phase crossover slopes. Both produce some extra latency of course, but phase equalization of input signal is usually easier to design. Some DSP gears don't have that option which is almost annoying.

 

[gnarly]

I know the theory and that many people swear by these types of crossovers. To me it seems like a great idea but I am a little skeptical that if in the real world "acoustically complementary" is realistic between 2 radically different drivers located at a set distance from each other that may or may not be ideal. In your experience can you actually measure the pre-ringing or lack thereof reliably "in room"?

I think you are spot on, questioning the reality of achieving acoustically complementary response....and most particularly between subwoofers and main speakers.
Subs and mains must be co-located to have any hope of producing acoustically complementary response, to anywhere other than a chosen listening spot.

Which for me, raises a very ironic point regarding the issue of potential pre-ring audibility. We hear about the issue all the time when it comes to crossovers, but why is it never discussed with multi-sub bass management?
Any program like Dirac or whatever, that uses any mixed phase filtering, has made phase corrections that do not have naturally balancing offsets, as they do in acoustically complementary crossovers.
Ever hear about anybody taking about pre-ring potential with their multi-sub bass management? I haven't. If optimization programs are using more than IIR to manage multi-sub, they sure as heck have potential.

I think of the sub to main crossover as just another crossover, like those in the main speaker. And like drivers in the main speaker that are co-located in a fixed manner for fixed acoustical results, I think it's optimal to have the sub or better said, the sub drivers, co-located in fixed manner.
Imo/ime, maintaining acoustically complementary crossovers between all driver sections is fundamental to excellent speaker design, whether crossovers are minimum phase or linear phase. And that ain't gonna happen when subs are located away from mains !

Anyway, yes, I think I can measure pre-ring potential accurately.
I think the correct way is as anechoically as possible , not "in-room" if that means at listening position. It's just another speaker measurement, that falls into the same camp as spinoramas, imo/ime.
The measurement is simply the set of on and off-axis impulse responses, particularly Step response. As it shows dips below zero prior to impulse peak, with potentially audible pre-ring.

I've found thru a lot of polar measurements of my DIY synergy horns, that it's kinda not worth paying attention to, as not much changes compared to good reference axis Step response.
I think that's because, even when fully acoustically complementary summation is breaking down as evidenced by variances in polars, the regions of frequency response that are capable of pre-ring are pretty small...well, at least for me,.... because I use steep crossovers.

Steep complementary lin phase crossovers minimize the potential lobing range between drivers, because the critical summation span is dramatically narrowed (vs low order crossovers). (I'm sure you are well aware of this...typing for group at large)

Here's the electrical crossovers I use with a 4-way syn horn that sits directly of top of a sub.
Xovers are at 100, 300, 750, and 3400Hz. All are 96 dB/oct LR.

Note how narrow the summation regions between drivers are. Take the low to mid crossover at 300Hz, it's probably only 40Hz wide within the range that matters, where both drivers are contributing relative equally (within 3dB of each other)
Those narrow regions are the only regions capable of potential pre-ring, because all other frequency regions are single driver section only.
Tone bursts confirm this, as there is zero envelope warpage in non summed frequency ranges..
The Step response is of the summed electrical sections...complementary works huh!

Hope I made sense...
I can't believe more folks haven't jumped into lin-phase crossovers, I guess not due to pre-ring scare.
And how many folks have jumped into mixed-phase sub optimization with no pre-ring concern at all.
A bit ironic imo

 

[Mort]

I've switched to no subs for primary music listening.

Not going back unless cardioid.

 

[Andreas007]

Lack of optimal positions. There are only two places where I could tolerate them visually but I already know these are quite bad in terms of sound.
Furthermore, neighbors and WAF.

 

[Oddball]

Things get complicated in life. If I evaluated my two wifes (one ex) like the subs, I would have not had 3 wonderful kids because I would become aware that ideal integration is not possible and better to stay Han Solo.

For me the ultimate test, and after all due attempts to integrate subs to the best of my abilities across various parameters noted above (aided by professional calibrator at the end), is that if I turn the subs off I miss them. For HT immensely and for stereo, well, it is still better and I can more easily add my "preference" to the low end (even if that might be considered as vandalism).

 

[CJPopovich]

Don’t sacrifice emotional coherence for the sake of time coherence. When you mess with the low-end—kick drums, low E strings, pipe organs, heavy synthesized bass—you’re losing the essence of the music. These frequencies are the foundation, and if you can’t reproduce them properly, you’re not just missing out on timing, you’re missing out on feeling. Let’s not forget, every live amplified concert uses piles of high-pass, low-pass, and non-phase-coherent arrays, with who knows what else happening in the crossovers. So, why are we pretending that’s not part of the game?

I totally get the appeal of reducing group delay where it makes sense. I have spent a lot of energy pushing gd low in the audible passband in my own designs. That said, to me, cutting off your bass response just to get a better impulse response graph? That’s a crime against the music and art. I’m all for people doing what makes them happy, but it blows my mind that so many are willing to strip away the core of the music, prop it up with a couple of thin supports, and call it an upgrade.

This isn’t some “big bass is the only thing that matters” argument, but I am making the case that bass is an absolutely critical part of sound reproduction. Sure, sometimes it doesn’t work in certain rooms, budgets or lifestyles, and if you need to make that compromise, that’s fine. But don’t fool yourself—it’s still a compromise if the fundamentals of the sound you are attempting to reproduce aren’t done so clearly and powerfully.

 

[fragzone]

I don't have a measurement mic yet, but using test tones I can roughly determine my MTM ported towers using 5 1/4 inch drivers get down to 35 hz more or less flat, with considerable response at 30hz and audible/perceivable response at 25hz at the MLP.

Comparing to my bookshelf speakers with the same sized woofers, it's immediately apparent that I'm missing the lower registers and it is no longer acceptable for me to listen to them outside of a near field application because I now know what I'm missing.

Comparing the towers to my akg371 it doesn't appear that my towers are actually missing much of anything in the lower regions which might be wholly unsurprising depending on the music choice. Although, there is something to be said about the visceral nature of a flat 20hz which not even perfectly extended headphones could replicate, from what I understand having spent some time on this site.

So yeah, no subwoofers on the immediate horizon because I am currently content with the vastly improved visceral nature provided by the lower bass of my towers in comparison to my bookshelves, and equally content with being ignorant to the wonders of subwoofers which I have thankfully yet to hear.

I would love to chase that dragon one-day but there's more things I need to optimise in my life before I go down that rabbit hole.

 

[alankila]

Don’t sacrifice emotional coherence for the sake of time coherence. When you mess with the low-end—kick drums, low E strings, pipe organs, heavy synthesized bass—you’re losing the essence of the music. These frequencies are the foundation, and if you can’t reproduce them properly, you’re not just missing out on timing, you’re missing out on feeling. Let’s not forget, every live amplified concert uses piles of high-pass, low-pass, and non-phase-coherent arrays, with who knows what else happening in the crossovers. So, why are we pretending that’s not part of the game?

I totally get the appeal of reducing group delay where it makes sense. I have spent a lot of energy pushing gd low in the audible passband in my own designs. That said, to me, cutting off your bass response just to get a better impulse response graph? That’s a crime against the music and art. I’m all for people doing what makes them happy, but it blows my mind that so many are willing to strip away the core of the music, prop it up with a couple of thin supports, and call it an upgrade.

This isn’t some “big bass is the only thing that matters” argument, but I am making the case that bass is an absolutely critical part of sound reproduction. Sure, sometimes it doesn’t work in certain rooms, budgets or lifestyles, and if you need to make that compromise, that’s fine. But don’t fool yourself—it’s still a compromise if the fundamentals of the sound you are attempting to reproduce aren’t done so clearly and powerfully.

I agree that frequency response is more important than any other metric, that seems to be well supported by research in human hearing. In my case, I'd like to have both of them correct. As I began to realize that the massive group delay spike is with the crossover, I spotted an option to run the sub without crossover as a full bandwidth device with anechoic frequency response from 19 to 150 Hz. Doing this immediately got rid of the 20 ms group delay rise, so I think it is definitely the crossover doing it rather than some intrinsic huge sound buffering in 7370A. There's some of that as well, of course, because this is a digital device with DSP.

To match the sub with the mains, I ended up experimenting with bunch of mains delay figures, and eventually settled on 6.2 ms for the mains which is in addition to the 8351B's DSP 7.5 ms delay before output starts, for total of about 13.7 ms of delay required to match phase between sub and 8351B in extended phase linearity mode. After that, I'm reading very similar group delay figures between 8351B alone, and 8351B+7370A together over a smooth section of the group delay near 70 Hz and I can't see any nulls. If GLM's negative autophase setting means that it adds delay to mains instead of the sub, then 165 degrees at 70 Hz would equal +6.5 ms delay to mains, but I don't know if this is how it works because the GLM manual doesn't describe the exact behavior of the phase function, and there is great risk of performing numerology here and this is site is not audiowitchcraftreview.

Once I eliminated the crossover, the sound is now basically nearly exactly as I used to have it with 8351B alone, except the bass hits much lower at full force, and apart from that 120 Hz acoustic problem which has a narrow group delay spike, the group delay looks nearly the same with or without the sub near the flat section I benchmark it on which is around 70-80 Hz. Whatever claims I made about the speaker being inverted turned out to be wrong, most likely. Unfortunate. I will edit the post later to strike that part out. (EDIT: no I won't, because I am not allowed to edit that post anymore.) I'll have to see about when I find some free time to play with some LR8 filters with variable delays, and see if I can replicate what I saw and perhaps finally understand what actually was actually going on when I was tearing my hair out trying to make it to work as I expected.

 

[gnarly]

This isn’t some “big bass is the only thing that matters” argument, but I am making the case that bass is an absolutely critical part of sound reproduction. Sure, sometimes it doesn’t work in certain rooms, budgets or lifestyles, and if you need to make that compromise, that’s fine. But don’t fool yourself—it’s still a compromise if the fundamentals of the sound you are attempting to reproduce aren’t done so clearly and powerfully.

That's my perspective too...that bass is an absolutely critical part of sound reproduction. It's the foundation for excellent sound, be it reproduced or live.


Like you, I run a lot of sub power to be able to produce my desired low frequency extension clearly, powerfully, with very low distortion. I have maybe thirty 18" subs or 18" equivalents, with about 30 kW to drive them.
A short lived foray into live-sound production got the collection started, and then I became enamored with DIY speakers and subs, comparing sealed, reflex, dual opposed designs, front loaded horns, etc.

If all my listening were in-room, I know the collection would never have grown so large. But I love to listen to powerful audio outdoors, where distinctions between the sub types, their processing, and integration with mains can be readily heard and appreciated.
That love for powerful outdoor listening has had it's cost though, beyond that of acquiring an insane amount of gear .... outdoors is so superior, both bass and throughout the spectrum...that it's become hard for me to take indoors all that seriously.
(Consolation prizes for being idiot to have all the speakers/subs/gear, is at least the speaker and sub cost is very low compared to commercial, and amps are all used prosound which are very economical, relatively. And I have learned a boatload about speakers.)

Anyway, again I so fully agree with most all the posts you've made.

Let’s not forget, every live amplified concert uses piles of high-pass, low-pass, and non-phase-coherent arrays, with who knows what else happening in the crossovers. So, why are we pretending that’s not part of the game?

This one I don't agree with.
It certainly may be true at the smaller end of the live-sound market, say regional and lower. But I think definitely not for international/national/ A level productions.

Any system such as Meyer, L'Acoustics, D&B, Martin, EAW, Danley, etc comes with amps and processing designed for phase coherence between main components, and optimal sub to main crossovers given a particular geometric setup. Several of them require mandatory training for purchase. Modeling software is used to adapt the systems to the particular venue's geometric placement requirements. I attend dozens of meetings on an annual basis, for instruction in large scale live-sound system measuring and set-up. It's often amazing the amount of modeling homework that goes into event planning, especially given developments in cardioid sub capability, and beam steering capability.

All the top drawer systems I've studied, the system high-pass and crossover subs-to-mains are carefully time and phase aligned ...array elements are carefully processed to maintain their phase alignments....in-fills, out-fills, and delay towers are time and phase aligned...etc.
Bottom line imo, there's a reason gigs like Montreal Jazz sound so good .

That kind of great outdoor sound is what I strive to recreate at home. Been lucky so far, cause it seems to be working (at least outdoors!)

 

[CJPopovich]

This one I don't agree with.
It certainly may be true at the smaller end of the live-sound market, say regional and lower. But I think definitely not for international/national/ A level productions.

We are very much in agreement -I'm speaking more about not using the beloved 1st and sometimes 2nd order crossovers in everything, no high pass filters, etc. to maintain the illusion of signal purity. Pro-audio absolutely time aligns, uses proper crossover design, etc, I'm more stating pro sound doesn't adhere to audiophile dogma/mysticism, they use the right tools for the job. I apologize for my lack of clarity.

 

[gnarly]

We are very much in agreement -I'm speaking more about not using the beloved 1st and sometimes 2nd order crossovers in everything, no high pass filters, etc. to maintain the illusion of signal purity. Pro-audio absolutely time aligns, uses proper crossover design, etc, I'm more stating pro sound doesn't adhere to audiophile dogma/mysticism, they use the right tools for the job. I apologize for my lack of clarity.

Thanks, and sorry for any of my misconstruing what you were saying. Like said, couldn't agree more with your posts.

Yeah, if folks think they are maintaining signal purity by omitting subs, or lower bass extension with floor standers, to reduce group delay etc.....
...well maybe they are from a pure mental projection point of view, but they are certainly throwing away musical righteousness, ime/imo.

That said, I do admit to continually trying to achieve signal purity with lower and more powerful bass.
Here's a link in a DIY thread, to one type of test I play with to analyze sealed vs ported.

Why is a critically damped Q factor bad?

Played around with Octave a bit more, denormalized the transfer function and have this plot, for Q=0.5, Q=0.7 and for a B4, all with approximate resonance frequencies of 30Hz. The Step response functions now show a settling time in seconds. The Vented box basically has 30Hz ringing superimposed...

www.diyaudio.com

I've also spent a lot of effort trying to find any audible tradeoffs in the system high-pass, ......between the group delay of using an IIR high pass..... vs no group delay but potential pre-ring using a linear-phase high-pass.
Biggest problem is, despite measurement differences, it takes me a lot of listening time and different music (and moods) to form definitive assessments.
Heck, I'm building six sealed 18" cabs right now, to make myself live with sealed for a few months to gather a longer term opinion. Knowing full well ported rocks Lol

 

[levimax]

I have maybe thirty 18" subs or 18" equivalents, with about 30 kW to drive them.

Wow!

That kind of great outdoor sound is what I strive to recreate at home.

Regarding imaging, one thing that is hard to do is try to recreate the sound of a large space in a small room i.e. a Cathedral in a bed room. In your "outdoor" experience how does the opposite work i.e. trying to create a "small room" like chamber music sound outdoors?

 

[Robbo99999]

Wow!


Regarding imaging, one thing that is hard to do is try to recreate the sound of a large space in a small room i.e. a Cathedral in a bed room. In your "outdoor" experience how does the opposite work i.e. trying to create a "small room" like chamber music sound outdoors?

In my view whether it sounds like it's in a small room or in a cathedral, etc should be created by the recording itself, the speakers are there just to play it back without any added colouring.

 

[levimax]

In my view whether it sounds like it's in a small room or in a cathedral, etc should be created by the recording itself, the speakers are there just to play it back without any added colouring.

Yes the "sonic cues" from the room the recording was made in are hopefully on the recording but the problem is when the recording it played back in a different room then that room's size and reflections becomes part of what we hear. That is why it is hard to make a small bedroom sound like a cathedral regardless of what is on the recording. To me it seems like a recording played outside, which will have little added room reflections, should be more likely to sound like the original room the recording was made in but I have never tried it. I am curious if while the "audio cues" of a small room are present if other "cues" from being outside (both audio and visual) overwhelm what is on the recording or not.

 

[Robbo99999]

Yes the "sonic cues" from the room the recording was made in are hopefully on the recording but the problem is when the recording it played back in a different room then that room's size and reflections becomes part of what we hear. That is why it is hard to make a small bedroom sound like a cathedral regardless of what is on the recording. To me it seems like a recording played outside, which will have little added room reflections, should be more likely to sound like the original room the recording was made in but I have never tried it. I am curious if while the "audio cues" of a small room are present if other "cues" from being outside (both audio and visual) overwhelm what is on the recording or not.

I think if you've got a recording that's been made in a cathedral (& if that has been done well to include the cathedral feel) then that will come over when you play it in your bedroom. Yeah, the room your speakers are in has some influence but that's why you buy speakers with good directivity so that reflections don't significantly/negatively affect what you're listening to - it's just all part of the reviews Amir does here on ASR with the spinorama and related to the work by Floyd Toole and the idea that you want Anechoic Flat speakers with good directivity.

 

[Flaesh]

another ugly box

and if, for example, it is like this? This could be a subwoofer box..

 

[Pieter1267]

As ex club DJ im always chasing power low for my fav tunes to play at home. The sub made a big difference. The biggest difference was 2 subs. Just switching mute on one and then back
to both is night and day. I could live without but i could also live without the F208s. In fact, the F208's do a fine job down low. I could live without my wife but likewise, life with 2 subs is just night and day. Highly recommended.

On top of that, if money is an issues: go for DIY Daytons and Crown or Behringer. The total is less than $1200. It blows away a lot of high end subs 3 times that money. That said, the SVS PB 1000 pro was fine too, if you dont need the spl.