Subwoofers that go below 30 hz for music

[Flaesh]

COTS subwoofers that go

JBL SUB18 for example. Plug holes and it will be better than mine old subs with $111 drivers .

 

[Frank Dernie]

I suppose when considered with playback of said 16Hz organ note on a playback system of subs, etc, then you might question what is the real world importance of reproducing the 16Hz part of the note when it's the overtones that are higher up that is what is really heard or "experienced" by the listener - and if it was only really the overtones that were important for the 16Hz note on the organ then you might not kill yourself trying to get your stereo to playback 16Hz properly, which might be what @Hayabusa is getting at. I think that's what he's getting at.

This is true but how "high fidelity" is it if the relative amplitudes of these overtones are changed a lot because of harmonic distortion?
The timbre of a note is defined by the amplitude of the overtones (and any fluctuation with time) so any change to these obviously changes the timbre - at what point this is audible, noticeable and important I don't know.
Audibility of bass distortion has always been said to be low but is that because listeners are less familiar with the timbre of instruments which play in the bass?

 

[Hayabusa]

You think????
Why are there so many different stops then? The organ builders built in LOTS of different overtones to create interest and variability.
The only pipes without extra colour added are the "flutes" AFAIK
In the Liverpool Metropolitan Cathedral organ - the first one I have been to younger than me - there are 4565 pipes and it can mimic a large proportion of a traditional orchestra (with various levels of accuracy...)

It isn't the biggest or most complex either.

If you believe that bollox the only musical instruments which don't distort are the flute family.

You are right I would have been better to quote the 'THD' or maybe call it THC 'Total Harmonic Content'

 

[Frank Dernie]

You are right I would have been better to quote the 'THD' or maybe call it THC 'Total Harmonic Content'

 

[Robbo99999]

This is true but how "high fidelity" is it if the relative amplitudes of these overtones are changed a lot because of harmonic distortion?
The timbre of a note is defined by the amplitude of the overtones (and any fluctuation with time) so any change to these obviously changes the timbre - at what point this is audible, noticeable and important I don't know.
Audibility of bass distortion has always been said to be low but is that because listeners are less familiar with the timbre of instruments which play in the bass?

Yes, I don't have the answers for that, it appears no one does. It's the kind of thing where you buy the best engineered sub you can find & afford that you think is worth the money. That graph that I linked a while back is one way to compare the subs tested but yeah we're all not sure on if the distortion criteria are too lenient. We're just back to the beginning again, at least we can see a comparison of the subs and choose the better performing ones if we want.

Following stuff is what I was gonna add as an idea, but too many practical holes in it, so in spoiler as not worth reading that much:
Was gonna say that one way of working out what kind of bass distortion is acceptable in the music you listen to would be to do headphone experiments that can be EQ'd to the same curve in the bass and if you could measure your headphones you'd be able to compare measured distortion levels at the EQ'd target, and then you could do listening tests to see if you notice any subjective differences in bass. Problems are that you need an accurate measurement device, mostly we'd say GRAS, and you'd also have to be sure you were getting the same bass performance on your head through things like hopefully not losing seal, but then you also have the influence of the rest of the frequency response of the headphone too, but I suppose that could be EQ'd to same target if a person owned a GRAS. I know from my own experience some headphones do bass better than others when EQ'd to same curve, albeit inaccuracies like I've said and I don't have a GRAS measurement device. The headphones wouldn't have the same group delay issues as subs can have I don't think too, so that's another point of innacuracy

 

[mwmkravchenko]

Yes, room gain is often forgotten. I get 100dB at 20hz with a single sub in my dedicated listening room. You typically get a much higher value than the CEA/CTA2010 tests tell you in an actual room, as they're measured outside at 2m.

Room gain is very dependent on wall construction. In Europe you have mainly masonry walls. Awesome room gain. In Canada, America you have wood framed walls. Essentially invisible below 30 hertz.

Mark

 

[mwmkravchenko]

Really?
I hadn't checked but on the basis of listening to a lot of 32' pipes on organs when on choir music tours to various cathedrals I had assumed it was higher since I can hear it rather than just feel it.

You can discern pitch, another way to say hear tones much lower than 20 hertz.

Here is one of the latest studies on low frequency perception. The criteria is twofold high enough SPL and freedom form extraneous harmonics.

Mark

 

[mwmkravchenko]

Ever checked the harmonic distortion of these tones? The fundamental is barely audible with all the harmonics on top of it...
(I mean the THD of the organ it self)

I read the comments in between. I'll bite. What ever the instrument produced, if it is picked up via mics with sufficiently small added distortions is what you would have heard there, at the original sound venue.

I take it that you really do not understand pipe organs. I'll add a little bit of information that may clarify some of the comments.

Pipe Organs have flue pipes, basically flutes, and reed pipes. They are more like a saxophone, or clarinet, Oboe, Bassoon.

The better organs use full length resonator pipes on top of the reeds. As in the pipe the metal reed is playing into is the full half wavelength of the note. This gives as much gravitas to the tone as is possible. There are many reeds stops that do not have full length resonators, and there are strong beat frequencies and weak fundamental or actual desired note played frequency.

Almost every note on a pipe organ is multifaceted, as in contains a multitude of harmonics.

Even a straight principal, diapason, flute etc has harmonic content.

Mark

 

[sigbergaudio]

You can discern pitch, another way to say hear tones much lower than 20 hertz.

Here is one of the latest studies on low frequency perception. The criteria is twofold high enough SPL and freedom form extraneous harmonics.

View attachment 474297


Mark

Do you perhaps have a reference to the study?

 

[mwmkravchenko]

Do you perhaps have a reference to the study?

Definitely. When I get back to the confuzer.

 

[olieb]

Do you perhaps have a reference to the study?

I found a link

https://docs.wind-watch.org/Pedersen-human-hearing-low-frequencies.pdf

These seems to be a collection of articles about infrasonics
The diagram is Fig 10 in the second article.

There seems to be no frequency "threshold" for hearing (perception by ear) it apparently is more a question of sound pressure.
But whether this perception is a "tone" (with a pitch) I do not know. (EDIT: I would be surprised as this is not what happens when I play 8....12Hz through in ear phones. The perception is more like sitting in an air pump
Very interesting.

 

[sigbergaudio]

Definitely. When I get back to the confuzer.

After a brief read it looks to imply the opposite, that we do not perceive pitch below 20hz.

 

[Titurel]

After a brief read it looks to imply the opposite, that we do not perceive pitch below 20hz.

Probably true, but that does not mean that we do not perceive sounds which are pitched below 20Hz, just that we do not perceive their pitch. That is, we are unable to reliably identify their pitch.

Think about it, musics evolve (or adapt) to their most usual milieu. For instance, music typically played in venues which won't support low sonics won't exploit (or employ) low sonics. The converse is undoubtedly true. Music for cathedrals has evolved to exploit and / or accommodate their characteristic acoustical properties, which include low and sub sonics. So, if you want to hear organ music as it was (probably) conceived, your system needs to be able to reproduce not only "pitched" events, like that 8Hz C, but also the sum and difference pitches easily created in such venues. BTW, organ music often takes advantage of such 'resultant pitches." That 8Hz capable organ is also capable of producing pitches below 8Hz, e.g., 4Hz (by playing the bottom C and G simultaneously).

 

[sigbergaudio]

Probably true, but that does not mean that we do not perceive sounds which are pitched below 20Hz, just that we do not perceive their pitch. That is, we are unable to reliably identify their pitch.

Sure, I was just curious about the claim that we could actually identify pitch below 20hz, so that is what I commented, not that we can't hear anything below 20hz.

 

[Titurel]

Sure, I was just curious about the claim that we could actually identify pitch below 20hz, so that is what I commented, not that we can't hear anything below 20hz.

Didn't mean to imply you did, but your observation did provide a convenient place to start discussing the musical information (and performance artifacts) which exists well below what we readily perceive as pitch.

 

[sigbergaudio]

Didn't mean to imply you did, but your observation did provide a convenient place to start discussing the musical information (and performance artifacts) which exists well below what we readily perceive as pitch.

The largest difference I perceive personally when you get response down to 15-20hz is the added sense of the recording space, and how things (on some recordings) feels larger.

 

[mwmkravchenko]

The papers I have are indeed pitch perception. Give me a few hours. Sensation is not pitch. I think everyone here understands that.

 

[mwmkravchenko]

Ok I have all my infrasound papers. They are all clear as mud. Some do say you cannot perceive pitch at lower frequencies. I can. I may be one of those strange super sensitive people to low frequencies. What I cannot find is the cut off for how low our pitch perception stops. If I remember correctly it was in the Japanese fellows testing.

The Japanese studies are interesting, and I seem to have lost them. I'll find them again.

Here is a link to my Google driver folder:

https://drive.google.com/drive/folders/1FVEbdHguDJNdGoHWoKo53PspDlwKeQ_t?usp=sharing

I have chased very low output for decades. Demonstrated it as well. It certainly is fun to watch peoples faces when they first hear a strong solid 16.8 hertz. Especially when it's clean. That is the bane of most subwoofers, the distortion masks the fundamental and it is all a one note mush.

I have had opportunity to design loudspeakers that did this well, and subwoofers that also did this well.

Mark

 

[Hayabusa]

I read the comments in between. I'll bite. What ever the instrument produced, if it is picked up via mics with sufficiently small added distortions is what you would have heard there, at the original sound venue.

I take it that you really do not understand pipe organs. I'll add a little bit of information that may clarify some of the comments.

Pipe Organs have flue pipes, basically flutes, and reed pipes. They are more like a saxophone, or clarinet, Oboe, Bassoon.

The better organs use full length resonator pipes on top of the reeds. As in the pipe the metal reed is playing into is the full half wavelength of the note. This gives as much gravitas to the tone as is possible. There are many reeds stops that do not have full length resonators, and there are strong beat frequencies and weak fundamental or actual desired note played frequency.

Almost every note on a pipe organ is multifaceted, as in contains a multitude of harmonics.

Even a straight principal, diapason, flute etc has harmonic content.

Mark

Again I only took the THD metaphor to illustrate the audibility.
Of cause I know each instrument has its own harmonics.....
I also stated that the harmonics came from the organ..

I also re-badge-ed THD to THC (Total Harmonic Content)

 

[Pieter1267]

I just finished building one of these monsters because I was frustrated with my modern "too small enclosure" subs https://shop.gsgad.com/collections/...ies/products/roundover-full-marty-single-unit . Compared to my 2 SVS SB-3000 this one sub puts out more SPL with about 30dB less distortion and about 80 ms less group delay at 20 Hz and plays flat and clean to about 15 Hz. These giant subs don't just play low, if you put a "pro" driver in them they will play clean to over 500 Hz with huge SPL. Between 40 Hz and 120 Hz is where "slam" lives and neither the small subs nor smaller mains speakers do as good a job as you would think with this range at high SPL. All in all for low volume listening it doesn't make much difference (see fletcher munson curve) but if you listen loud, high SPL clean bass with extension is a real treat and I am starting to think that the "modern" approach of small enclosures with big drivers and lots of x-max may not be the way to go.

My advice is don't just look at SPL at 20 Hz. Some modern subs have over 100 ms group delay at 20 Hz which does not sound good but more importantly it makes integration really hard. Same with distortion, the common wisdom is we are less sensitive to distortion at low frequencies which is true but a lot of subs have distortion over 30% and some approaching 100% and less sensitive does not mean distortion doesn't matter. Finally be aware that again because of the"fletcher munson curve" LF, even at 90 dB, does not sound "loud". So while it seems crazy to want over 100 dB at 20 Hz it really isn't that loud even though it is hard to achieve. Have fun.

What a great post! I fully agree higher xo for full chest punch is what you want at higher spl. After lots of thinking this is why i went and got me 2 Skram subwoofers that are designed to do flat between 28 and 140hz. For my thing ive settled at 98 but you are so right. Get a sub that performs well over 100hz if you want loud chest punch, and leave the nice main speakers how big they are, at as high you can high pass them as possible.