Understanding subwoofers

[Oddball]

Trying heorically not to make this sound like advertising, but I actually DO help our customers with subwoofer integration, I even help analyze rew measurements and suggest EQ - and recently made a tool to help them do this themselves. We of course also make systems where the subwoofers are integrated out of the box, which would be the best approach, but I do this even for customers who purchase subs and have speakers from other brands.

It's expensive, but the chance of getting good sound is way higher (and/or effort needed is way lower). It's hard to get people to understand the benefit of this, most don't understand until after they've made the purchase and got the assistance.

I talk to so many people who struggle with subwoofer integration, so for those in this thread who find it easy, this is not the case for everyone. Some don't have a system that is well suited for subwoofer integration, some aren't technically inclined / don't understand how it all works, and/or don't want to spend enough time to understand. Finally not everyone are clear on what benefit they are expecting from a subwoofer. So they're essentially purchasing one for the wrong reasons, not understanding that they may need other speakers as well to get the sound they are looking for. Or perhaps the issue is the room, so then we have to open the can of worms that is acoustical treatment, speaker/listening position placement, etc etc.

I have no doubt that you are going the extra step for the customer, which is always a good practice. My reference was more to larger sub manufacturers that have their DSP and apps that can help for sure but can take you only so far. SVS is working on their auto EQ, but I am honestly not expecting that much in terms of integration with other (non-sub) speakers.

Bass management is complex, and if people really don't want to spend much time with setting it up, for passive speakers the easy way out is called Dirac ART. For active speakers and sub modules it also does not appear to be rocket science and integration is more intuitive. Not addressing Trinnov as don't think it's cost effective. Want to do it otherwise? Well it will be a much more difficult process.

 

[Jaxx1138]

Trying heorically not to make this sound like advertising, but I actually DO help our customers with subwoofer integration, I even help analyze rew measurements and suggest EQ - and recently made a tool to help them do this themselves. We of course also make systems where the subwoofers are integrated out of the box, which would be the best approach, but I do this even for customers who purchase subs and have speakers from other brands.

It's expensive, but the chance of getting good sound is way higher (and/or effort needed is way lower). It's hard to get people to understand the benefit of this, most don't understand until after they've made the purchase and got the assistance.

I talk to so many people who struggle with subwoofer integration, so for those in this thread who find it easy, this is not the case for everyone. Some don't have a system that is well suited for subwoofer integration, some aren't technically inclined / don't understand how it all works, and/or don't want to spend enough time to understand. Finally not everyone are clear on what benefit they are expecting from a subwoofer. So they're essentially purchasing one for the wrong reasons, not understanding that they may need other speakers as well to get the sound they are looking for. Or perhaps the issue is the room, so then we have to open the can of worms that is acoustical treatment, speaker/listening position placement, etc etc.

Not to blow smoke, but I have monitored your latest creations. You do some great work. I am really excited about the cardiod pattern in the lower frequencies. I did my own research on this back at Harman international back in the mid 2000's. I was surprised at the image/soundstage improvement. The concenric stuff is also awsome. One of my colleagues at Harman now does all the system design for KALI (concentric). Love your stuff. Dont stop, you are on a winnng streak with your latest designs, including the subs. Great work. Get some over to ERIN for review. I hope to have a pair of your Saranna's someday. Active loudspeakers are the future.

 

[Oddball]

I have heard distorted subwoofer bass and I have heard clean subwoofer bass. I prefer clean and I think most people would if they got a chance to hear it. Why not try to get it right even if it is hard.

It is trivially easy for me to localize a clean playing sub down to 50 Hz.... 40 Hz is where it starts getting hard. Same conclusion a new study has shown https://www.audiosciencereview.com/forum/index.php?threads/bass-direction-is-audible.55079/ Nothing to do with "evelopment".

There are fundamental differences in co-locating subs and mains (or full range speakers) and splitting subs and mains regardless of the integration solution and there are trade offs to be aware of. Modern automatic systems can work very well in some situations and I am quite aware of what is out there and own several including DLBC and I will try ART when they release if for PC but we are very far from having bass issues in small rooms being a "solved problem".... but progress is not doubt being made.

Subwoofer distortion is easy - not hard. Hard on the budget though. More subs or more expensive and larger subs - less distortion. I would not be telling people that they need to get 4 subs if they are happy with 2. Obviously distortion with 4 would be lower.

It is trivially easy to localize a clean playing sub down to 50hz? Can you please let us know more about how do you manage that and under what circumstances. Kind of flies in the face of the common approach but it is always interesting to learn new things. The link you provided seems not to be relevant to small rooms.

As far as the last paragraph, the only automatic solution that will let you explore all the differences you noted will be Dirac ART. I sometimes just get tired repeating the same thing in every bass thread to people that either don't understand the ART concept or/and did not try it, but then I think it is important to continue saying the same thing until it actually becomes mainstream knowledge. Bass management is solved - at least for me.

 

[DY2]

O întrebare despre măsurătorile tale, știi nivelul SPL la poziția de ascultare pentru scanarea pe care ai efectuat-o?

Hi levimax,

To give you the most accurate data, I checked the calibration from that session. The sweep was performed at an average level of 83 dB SPL, with peaks reaching 93.7 dB at the listening position.

Instead of just screenshots, I think it's better to share the actual .mdat file with you. This way, you can look at the distortion, phase, and impulse response in detail. I believe in being as transparent as possible with these results.

https://drive.google.com/file/d/1ljp6dCUXpTCm7SQ_X9CtoqUmkca8bm5k/view?usp=sharing

 

[Keith_W]

I am really excited about the cardiod pattern in the lower frequencies. I did my own research on this back at Harman international back in the mid 2000's. I was surprised at the image/soundstage improvement.

If you don't mind me asking, who are you? A Harman researcher hiding in our midst is always exciting! And do you have a link to some publications about the benefits of cardioid bass?

 

[TimVG]

I actually use two stacked subs under LS50s for speaker stands.

Do you compensate for the change in baffle step because of this?

 

[Sigberg Audio]

Not to blow smoke, but I have monitored your latest creations. You do some great work. I am really excited about the cardiod pattern in the lower frequencies. I did my own research on this back at Harman international back in the mid 2000's. I was surprised at the image/soundstage improvement. The concenric stuff is also awsome. One of my colleagues at Harman now does all the system design for KALI (concentric). Love your stuff. Dont stop, you are on a winnng streak with your latest designs, including the subs. Great work. Get some over to ERIN for review. I hope to have a pair of your Saranna's someday. Active loudspeakers are the future.

Don't want to derail the thread completely, but just wanted to briefly thank you for your kind words, much appreciated!

 

[Oddball]

Don't want to derail the thread completely, but just wanted to briefly thank you for your kind words, much appreciated!

I don't think you would derail the trail discussing your work with subs. It is definitely a step forward and beyond and very interesting. From what I understood in other threads, it has its own price, but don't think we are necessarily discussing the price in this thread.

 

[levimax]

Subwoofer distortion is easy - not hard. Hard on the budget though. More subs or more expensive and larger subs - less distortion. I would not be telling people that they need to get 4 subs if they are happy with 2. Obviously distortion with 4 would be lower.

Many people don't understand that their normal speakers are held to a standard of -50dB THD (by Amir) but the subwoofer standard from CEA-2010 is ~-10 dB THD which I feel is misleading. Whether they chose to do anything about it is up to them.

It is trivially easy to localize a clean playing sub down to 50hz? Can you please let us know more about how do you manage that and under what circumstances. Kind of flies in the face of the common approach but it is always interesting to learn new things. The link you provided seems not to be relevant to small rooms.

From the conclusion of: Auditory localisation of low-frequency sound sources. Madalina Anamaria Nastasa submitted 7/29/2022

As far as the last paragraph, the only automatic solution that will let you explore all the differences you noted will be Dirac ART. I sometimes just get tired repeating the same thing in every bass thread to people that either don't understand the ART concept or/and did not try it, but then I think it is important to continue saying the same thing until it actually becomes mainstream knowledge. Bass management is solved - at least for me.

I am glad ART is working well for you. Maybe you can put in a good word with DIRAC for the PC users that they should hurry up and release the PC version. While ART it intriguing it is not the last word or the only solution, Trinnov has some interesting products and good old DBA, while difficult to execute, is theoretically a very good solution as well. Hopefully some easier and cheaper solutions will be appearing.

 

[Sigberg Audio]

From the conclusion of: Auditory localisation of low-frequency sound sources. Madalina Anamaria Nastasa submitted 7/29/2022

View attachment 529631

This conclusion cannot be readily translated to "subwoofers are localizable at the same frequencies in a domestic setting".

 

[levimax]

This conclusion cannot be readily translated to "subwoofers are localizable at the same frequencies in a domestic setting".

OK but I just tried this experiment again to confirm my memory of the last time I tried it. I output the REW sine wave generator to one of my subs (18" 320 liter with measured less than 1% THD @ 20 Hz). I sat at my LP in a swivel chair and closed my eyes and listened to see if I could hear where the sound was coming from and spun my chair around and then tried to point at what sounded like the source. From 50 Hz up is was trivially easy, at 40 Hz it was getting very hard and I was probably only able to judge ~ +/- 90 degrees and at 30 Hz there was no chance for me to hear the direction at all. I can't say what interaction the room played or didn't play or anything else, and I would not be surprised if the room or something else was part of what I was hearing but the bottom line is having subs in different places in the room sounds different at the LP for frequencies above 40-50 Hz. I have read countless similar accounts which are alway dismissed as "high distortion subs" or something else. In this case the science, after many decades of being wrong/incomplete, is finally catching up with observations.

 

[Oddball]

Many people don't understand that their normal speakers are held to a standard of -50dB THD (by Amir) but the subwoofer standard from CEA-2010 is ~-10 dB THD which I feel is misleading. Whether they chose to do anything about it is up to them.

From the conclusion of: Auditory localisation of low-frequency sound sources. Madalina Anamaria Nastasa submitted 7/29/2022

View attachment 529631


I am glad ART is working well for you. Maybe you can put in a good word with DIRAC for the PC users that they should hurry up and release the PC version. While ART it intriguing it is not the last word or the only solution, Trinnov has some interesting products and good old DBA, while difficult to execute, is theoretically a very good solution as well. Hopefully some easier and cheaper solutions will be appearing.

Normal speakers are not really meant to be stretched to its limits. Even Revel 328s that Amir and many of us admire are not a subwoofers. It handled 96dB test admirably, but the if you push it to 105dB it will just fall apart. Saving the big towers for big SPL and taking on the low end by subs is what is actually the only serious game in town for the reference levels. I actually like what Perlisted did in their design of S towers - it really tells you that you need to get the subs. Same with 1528 Arendals. The bass roll off just tells you what you need to do. Even in designs like Heco (my speaker), it is not really true that they can follow the extended low end curve they have at 95dB to 105dB.

The research you point out continues to be irrelevant for the real rooms and environments. My question was: How do YOU effortlessly localize bass above 50hz and under what circumstances. Still waiting for an answer if there is one. Could be as simple - that happens only when the moon is full.

I have ART, so PC users should put the pressure to Dirac to release it for PC. I don't really have skin in the game as not moving to PC platform. We do know it has been in Beta for quite a while, and some of our members are using it as such.

I don't want to comment on Trinnov and their solutions as they require strict placement, rectangular room and significant budget. It is not a solution that most people should aspire too. Trinnov is limited to custom installation market and does not even support CEC. It is just a different ball game altogether.

 

[Sigberg Audio]

OK but I just tried this experiment again to confirm my memory of the last time I tried it. I output the REW sine wave generator to one of my subs (18" 320 liter with measured less than 1% THD @ 20 Hz). I sat at my LP in a swivel chair and closed my eyes and listened to see if I could hear where the sound was coming from and spun my chair around and then tried to point at what sounded like the source. From 50 Hz up is was trivially easy, at 40 Hz it was getting very hard and I was probably only able to judge ~ +/- 90 degrees and at 30 Hz there was no chance for me to hear the direction at all. I can't say what interaction the room played or didn't play or anything else, and I would not be surprised if the room or something else was part of what I was hearing but the bottom line is having subs in different places in the room sounds different at the LP for frequencies above 40-50 Hz. I have read countless similar accounts which are alway dismissed as "high distortion subs" or something else. In this case the science, after many decades of being wrong/incomplete, is finally catching up with observations.

I guess I should give context to my stance here.

In most situations it is beneficial from a sound quality / distortion perspective to cross over a subwoofer relatively high, to reduce the load on the main loudspeaker.

The main counterpoint would be that crossing the subs high makes them localizable, something that is then of course implied as not desirable.

Why do we have subwoofers? Typically not to sit in svivel chairs and listen to sinewaves. Most of us use it to listen to music.

Then the question becomes, at what crossover frequency is a single subwoofer localizable to the point of becoming annoying during playback of music? In my experience, the answer to this is beyond 100-120hz on a competent, low distortion subwoofer. Not 40hz.

 

[MKR]

If you don't mind me asking, who are you? A Harman researcher hiding in our midst is always exciting! And do you have a link to some publications about the benefits of cardioid bass?

Hey Keith … Cardioid bass is where it’s at in my humble opinion (at the risk of offending the DIRAC lovers in our midst… not DLBC, not ART, not room treatment, etc, etc), worth your deeper investigation to be sure

My prior post (which was effectively made fun of by some, but I was serious)…

Post in thread 'Understanding subwoofers'
https://www.audiosciencereview.com/...s/understanding-subwoofers.71126/post-2584111

 

[thcdru2k]

Cardioid implementation through fully active towers is the most elegant solution. I think simplicity of install is a huge plus and looks so clean. The downside is cost.

Achieving similar behavior with multiple subs is possible but comes with tradeoffs. It increases complexity, requires precise placement and timing, and is harder to implement consistently. It is also less clean from a system and visual standpoint.

 

[Oddball]

OK but I just tried this experiment again to confirm my memory of the last time I tried it. I output the REW sine wave generator to one of my subs (18" 320 liter with measured less than 1% THD @ 20 Hz). I sat at my LP in a swivel chair and closed my eyes and listened to see if I could hear where the sound was coming from and spun my chair around and then tried to point at what sounded like the source. From 50 Hz up is was trivially easy, at 40 Hz it was getting very hard and I was probably only able to judge ~ +/- 90 degrees and at 30 Hz there was no chance for me to hear the direction at all. I can't say what interaction the room played or didn't play or anything else, and I would not be surprised if the room or something else was part of what I was hearing but the bottom line is having subs in different places in the room sounds different at the LP for frequencies above 40-50 Hz. I have read countless similar accounts which are alway dismissed as "high distortion subs" or something else. In this case the science, after many decades of being wrong/incomplete, is finally catching up with observations.

Swiveling chair? 1% THD at 20hz (at what SPL)? Oh dear now we are in the seriously scientific territory and not much more to say. I rest my case.

 

[levimax]

.Then the question becomes, at what crossover frequency is a single subwoofer localizable to the point of becoming annoying during playback of music? In my experience, the answer to this is beyond 100-120hz on a competent, low distortion subwoofer. Not 40hz.

It depends a lot on the music. For "steady state" music I can't tell @ 100 Hz +. For something like a Jazz band opening with a long bass solo stage right and then joined in with the rest of the band and singer it can sound pretty weird. I find side located subs are not as noticeable as a sub behind me. I have never liked rear subs and the biggest difference I noticed when spinning in my chair was that sound in front and behind had the most obvious differences. From a survival in the jungle point of view this makes sense. From my subjective experience having the subs and mains colocated always sounds "right" (as far as locating things go) while splitting them around the room is more variable, free subjective observation and worth every penny.

One other question I have is why is the Madilina study not translatable to small rooms? It may not be perfect but it certainly is not completely unrelated and it would be a stretch to say completely "not translatable", more like "points to a need to revise current thinking and do more studies."

 

[levimax]

Swiveling chair? 1% THD at 20hz (at what SPL)? Oh dear now we are in the seriously scientific territory and not much more to say. I rest my case.

Try it yourself and see, it might change your perspective, the Madelina study clearly shows there is more research needed and localization threasholds are far from settled science. What is your case exactly?

 

[Oddball]

My case is below. Really happy with it. Subs with ART are going to 100hz and bass localization was never better. Flies in the face of all my previous experiments and stups, but I am not shy to admit it. I was trying my best to get to something that ART does so much better with zero effort.

Don't mind the bed, it is just another convenience feature. I'd take it anytime over the swivel chair that has been resting in the cellar for years.

 

[levimax]

My case is below. Really happy with it. Subs with ART are going to 100hz and bass localization was never better. Flies in the face of all my previous experiments and stups, but I am not shy to admit it. I was trying my best to get to something that ART does so much better with zero effort.

Don't mind the bed, it is just another convenience feature. I'd take it anytime over the swivel chair that has been resting in the cellar for years.


View attachment 529653

I know you have a receiver but not sure what else (besides a boat load of speaker and subs ). Would it be possible to play level matched sine waves into the different subs to see if you can locate them when you switch between them? If not music is better to listen to anyway