Subwoofers that go below 30 hz for music

[levimax]

Sorry, what does COTS mean?

 

[kyuu]

Sorry, what does COTS mean?

Commercial Off The Shelf, presumably. As opposed to DIY or something otherwise not available for purchase directly. Don't know what measurements are being referred to, though.

 

[sigbergaudio]

All this talk, and still hardly any mention of COTS subwoofers that go below 30Hz other than the KH750?

If someone can provide an option that measures better than the KH750, I'm all ears.

Do you have any measurements of the KH750 then?

 

[DrSpan]

The location of a null at a measurement position just means that is not a good place to listen from. All modes have nodes (nulls) and anti-nodes (peaks) in both the fundamental and harmonics and the magnitude to which they are excited is influenced by the position of the excitation (speaker) in the room, and the extent to which they are heard depends on where the listening chair is placed.
The sound can be improved by positioning of speaker and listener in the room before using DSP compensation.

I know this.
Its just that that as far as i know it is mathematically predictable. Meaning you can predict to a high (but not final) degree If a Room`s proportions are problematic or not.
I have experienced untreated rooms where it simply was impossible to place a sub. No matter where we tried it. Tried even dual subs after the theory that you sometimes
can control a room better. Then build a huge helmholz absorbert and had a minor betterment. When we realized how much treatment was needed
we gave up on the room.
I don`t doubt there is a lot i don`t know that is why i watch tutorials and read here and there and i never saw a discussion where the Room is beeing that much from the equation that in this one here especially when we are talking above average cause we are at the limits of hearing and and Room behavior with these huge wavelengths so i was a bit surprised that everyone is recommending Sub models and Enclosure principals and almost nobody asks what the room looks like and what acoustic measurements the room has. I personally would start there and then talk about tools.
Of course by now i have lost the overview of this thread as i cant keep up reading every single new comment cause i admit its not my first priority at present and there is only so much time we have in life.
Anyhow. I think there are better qualified people than me here so in the end it will all go well.

Peace

 

[sigbergaudio]

I know this.
Its just that that as far as i know it is mathematically predictable. Meaning you can predict to a high (but not final) degree If a Room`s proportions are problematic or not.
I have experienced untreated rooms where it simply was impossible to place a sub. No matter where we tried it. Tried even dual subs after the theory that you sometimes
can control a room better. Then build a huge helmholz absorbert and had a minor betterment. When we realized how much treatment was needed
we gave up on the room.
I don`t doubt there is a lot i don`t know that is why i watch tutorials and read here and there and i never saw a discussion where the Room is beeing that much from the equation that in this one here especially when we are talking above average cause we are at the limits of hearing and and Room behavior with these huge wavelengths so i was a bit surprised that everyone is recommending Sub models and Enclosure principals and almost nobody asks what the room looks like and what acoustic measurements the room has. I personally would start there and then talk about tools.
Of course by now i have lost the overview of this thread as i cant keep up reading every single new comment cause i admit its not my first priority at present and there is only so much time we have in life.
Anyhow. I think there are better qualified people than me here so in the end it will all go well.

Peace

But it's not like you choose different type of subs based on your room. What is often problematic is that people are pretty stuck with regards to the main listening position. If one were able to move that, you could move out of the null. If you insist one sitting where you're currently sitting, not being able to test perhaps rotating the room 90 or 180 degrees, then it is often limited what you can do.

You will never have a room that cannot support 20hz, but you can certainly have a room where a certain listening position will be very problematic for some frequencies due to dips in the frequency range.

Dual subs will normally help, but again depends on both listening position and positioning of subs. Asymmetric positioning is often better, while most people put the subs in symmetrical position if they have two (looks better).

 

[BluesDaddy]

Pipe organs are basically a spaceship and even so C2 will be more seismic than sound. Why is it so? Well because it lags in time progressively and in the way masks it self. You can use space fundamental to compensate for it partly or even completely, no sub's alone won't get you there. When choosing sub's pay attention to overall linearity trough SPL and capability in lower to mid 30's where defining peeks will be and ensuring it does it proper.

Thanks for sharing this. I was aware how complex Pipe organs are, but this was a fascinating deeper dive. My musician wife sitting next to watching would comment about the same time on some points.

 

[bachatero]

Do you have any measurements of the KH750 then?

Right here: https://audiosciencereview.com/forum/index.php?threads/i-measured-10-subwoofers.49042/post-1756741

 

[sigbergaudio]

Right here: https://audiosciencereview.com/forum/index.php?threads/i-measured-10-subwoofers.49042/post-1756741

Looks pretty decent.

 

[bachatero]

Looks pretty decent.

THAT'S WHAT I WAS SAYING! The complainers are dunking on the KH750 but aren't providing a better alternative.

 

[sigbergaudio]

THAT'S WHAT I WAS SAYING! The complainers are dunking on the KH750 but aren't providing a better alternative.

I haven't seen any dunking, but okay. There are of course more powerful subwoofers than this one, but everything comes with some kind of compromise. Larger box, more expensive, etc.

 

[Shiva]

How about this offering from JTR. Does it beat the KH750...?

Data-Bass: Subwoofer Measurements

data-bass.com

 

[Oddball]

Lol, watching this thread and having so much fun.

Everyone needs to understand what they want and then the question is how to achieve it. Going below 30hz is easy, though it might not be cheap. How much lower one wants to go and with what distortion levels is individual preference question. I don't like bass below 15 hz, so I designed my HT to that requirement and can live with distortion up to that range.

Another question is how you manage decay with your subs and if willing to invest in additional subs to do that - with assumption you have frequency response in control. Decay is going to be the worst enemy of sub 30hz response. How phase and group delay looks like is what in my mind comes after these considerations. Might not be much you can do about those anyway.

Putting 2 subs in the front and 2 in the back in full or at least some kind of double bass array with backs out of phase with fronts will IMO do most you can do without ART or Wave-forming. ART also does not work below 20hz so kind of not a solution for the last octave.

I have two of these up front - 13.8" 1kW amp each (actually PC 4000 but measures near this one as no other measures available)

And two of these in the back - 2x13.8" drivers 1.2kW amp each

For a bit over EUR 10K for the 4 of them very expensive, but also for my needs probably more than I will ever need.

Once you have that covered, I don't think you will actually find any beauty or satisfaction in it. It is borderline hear/feel situation that obviously reference system should have, but I am bit more concerned about 30hz - 100hz range response, so I use additional "subs" to reinforce and smoothen response in that range.

EDIT: Both charts per Audioholics and James Larson that is IMO their best speaker reviewer.

 

[nagster]

Frequency Response: 13–30 Hz ±4 dB
　　Phase Response: 13–30 Hz ±30°
　 　Linear Peak SPL: 125.5 dB with crest factor >10.5 dB (M-noise), 125.5 dB (Pink noise)

VLFC

Very Low Frequency Control Element

meyersound.com

 

[sigbergaudio]

It might also be worth mentioning that 20hz is sometimes perhaps getting too much attention when talking about subs. There are quite large differences in maximum capacity in the 40-100hz area between subs as well, and at the end of the day most of the punch and impact in music is in this area, not at 20hz.

 

[Sokel]

40-100hz area between subs as well, and at the end of the day most of the punch and impact in music is in this area, not at 20hz.

Make that 200Hz if we're talking about serious punch.

 

[sigbergaudio]

Make that 200Hz if we're talking about serious punch.

Indeed, but then we are outside of what people would normally assign to their subwoofers, that's why I stopped at 100hz. But I agree. Our speaker systems have dedicated drivers for the 100-600hz area for a reason.

 

[ZolaIII]

There is low peak and main bass peek, you can get peeks and lot higher but this two will be defining in greater majority of materials. Still they shouldn't be confused for each other. I like good acoustic drum session and that won't change.

 

[Elgrosso]

Pipe organs are basically a spaceship and even so C2 will be more seismic than sound. Why is it so? Well because it lags in time progressively and in the way masks it self. You can use space fundamental to compensate for it partly or even completely, no sub's alone won't get you there. When choosing sub's pay attention to overall linearity trough SPL and capability in lower to mid 30's where defining peeks will be and ensuring it does it proper.

I knew they were complex but didn’t expect that much, so I searched for more.
Here’s an older one that goes a bit into details :

In french but also very illustrative so you’ll get most of it, jump to 5 min for the principle, 8 min about fabrication, 12 min the tuning and more.

 

[levimax]

It might also be worth mentioning that 20hz is sometimes perhaps getting too much attention when talking about subs.

I recently built a "giant" sub (Ported, 11 cubic ft., 18 " pro-driver) to replace 2 small DSP subs (1 cubic ft, sealed, 13" driver). The main measured differences are that the big sub has higher SPL, less group delay @ 20 Hz (20 ms vs 100 ms) and much less distortion @ 20 Hz (~1% vs ~30%+). Switching between them when playing music with LF content or doing sweeps the main thing you notice is that the giant sub sounds "cleaner", it just makes low sound that you feel more than hear and then it stops. The smaller subs makes 20 Hz sound but they are also making lots of other sounds and it seem to carry on longer. My takeaways are that clean 20 Hz is hard with a lot of costs and diminishing returns but can be fun in limited circumstances. My bigger takeaway is that it is better to not try to make 20 Hz "sounds" unless the sub can do it well. Sloppy bass below 30 Hz sounds worse than no bass below 30 Hz.

 

[starfly]

All this talk, and still hardly any mention of COTS subwoofers that go below 30Hz other than the KH750?

If someone can provide an option that measures better than the KH750, I'm all ears.

I just decided to order the Dynaudio 9S to pair with my Kali IN8-V2 monitors in my office. It should go down to 22hz @85dB +/-3dB. Haven't found any measurements yet though. I was also looking for subs that can go down well below 30hz that also didn't cost as much as the KH750 (I paid around $1K for the Dynaudio). And I needed the additional feature of having XLR inputs/outputs.

I'd be happy to try and take measurements of the subwoofer, but all I have is a UMIK-1, and not sure if that's sufficient to properly measure a subwoofer. And I don't have an anechoic chamber in my house