How Deep Must the Bass Be?

[audioresearch]

I'm interested in people's opinions about how low the lowest frequency a subwoofer/woofer can produce with "acceptably low" distortion should be.

I'm interested only in the lowest frequency that can be heard, not just felt, regardless of how high the spl level needs to be for that to happen. I once heard a subwoofer being demonstrated which rattled the metal door on a wall-mounted electric service box on the other side of the room but I heard nothing whatever other than that metal door shaking-I do not care about the room vibrating or things in the room vibrating and making their own sounds, I only care about what I can hear that is emanating from the speaker.

Also, I am interested in people's opinions as to whether the spl level of the lowest frequency that can be heard needs to be so high to sound "loud" that it will cause hearing damage. What spl level at 20Hz is the threshold for causing hearing damage if listened to continuously?

I did not define above "acceptably low distortion" or "loud"-please give your own opinions on what values those should be.

I hope Amir can reply to this as I'm very curious to know his opinions. And by the way, Amir, thank you very much for the work you are doing and for the fact you base your work on science & audio engineering such as research findings from the AES and some of its well known luminaries such as Floyd Toole and Klippel.

 

[Blumlein 88]

Don't know you'll get an exact number here. Our threshold for 0 phons is about 72 db SPL at 20 hz, 60 db SPL at 30 hz, and 50 db SPL at 40 hz.

For music, there is very little to be gained below 40 hz. But for instance 80 hz the threshold is 30 db SPL. So 2nd harmonic distortion of 10% would be heard about as well as the 40 hz fundamental.

 

[Ken Tajalli]

Your neighbours don't care about the distortion bit!
But seriously, anything below 40Hz is not music, but sound effect.
Good for explosions, thunder, banging on your front door . . .

 

[dfuller]

I think it's reasonable to expect less than 3% THD to about 70hz in a decently sized standmount speaker (8" woofer) at 96dB/1m. Anything beyond that is gravy - you either need god-tier crazy high linear excursion drivers (see: Purifi and equivalent), big drivers (10" at the bare minimum) in ported or TL enclosures, or multiple drivers (big floorstanding towers e.g. F328).

 

[ryanosaur]

Piano goes down to 29 hz.

Is that not music? Or did every Composer and/or Pianist decide somewhere that they shouldn’t use those keys to the left of that low E which a Bass can play at ~40Hz out of convenience to some flawed paradigm audiophiles will use to define the lower end of Speaker performance?

 

[Philbo King]

Piano goes down to 29 hz.

Is that not music? Or did every Composer and/or Pianist decide somewhere that they shouldn’t use those keys to the left of that low E which a Bass can play at ~40Hz out of convenience to some flawed paradigm audiophiles will use to define the lower end of Speaker performance?

Unless the piano is a Bosendorfer it is unlikely the lowest note on a piano contains much amplitude of the fundamental. Most piano bass notes are primarily harmonics.
For example:

The Spectral Complexity of a Single Musical Note

On page 25 of the most recent January issue of the IEEE Signal Processing Magazine the following interesting spectral plot was presented. That...

www.dsprelated.com

 

[Ken Tajalli]

Piano goes down to 29 hz.

Is that not music? Or did every Composer and/or Pianist decide somewhere that they shouldn’t use those keys to the left of that low E which a Bass can play at ~40Hz out of convenience to some flawed paradigm audiophiles will use to define the lower end of Speaker performance?

You forgot Organs at some venues, the can go to 16Hz.
But in a domestic audio setup, well . . .
BTW, Audiophiles insist on 20Hz or less, they EQ the hell out of their system to get it

 

[Blumlein 88]

Piano goes down to 29 hz.

Is that not music? Or did every Composer and/or Pianist decide somewhere that they shouldn’t use those keys to the left of that low E which a Bass can play at ~40Hz out of convenience to some flawed paradigm audiophiles will use to define the lower end of Speaker performance?

That is why you have a hard time giving a defined number in hertz. Some organs have that 16 hz pipe. Do we say we need 16 hz? If you love organ music maybe.

Just beaten to the punch by Ken Tajalli.

 

[hege]

Your neighbours don't care about the distortion bit!
But seriously, anything below 40Hz is not music, but sound effect.
Good for explosions, thunder, banging on your front door . . .

So if everything even above 40Hz in some "song" is made of sound effects or synthesized sounds, is it still music?

Don't know why even bother responding to these threads.. just leave the standard link here:

BASS!

Post some nice examples of tracks that can challenge your system/headphones with lower spectrum notes. Try to include not only tracks from a "reference test suite" category but also those that are fun to listen (or you like personally). Although it's natural to expect some electronic music...

www.audiosciencereview.com

 

[audioresearch]

Oh, in a similar vein, let me ask people's opinions on the Danley DTS-10 and the fact in general that Danley seems to think frequency reproduction down to something like 5 or 10 Hz is important. Do you think so? In fact, does anyone know if the DTS-10 or any other Danley speaker being sold really outputs loud enough spl at subsonic frequencies to even be considered loud enough to make a difference?

Can anyone comment on whether his tapped horn theory is for real? I once Googled this and found something by some acoustics professor somewhere supposedly proving that tapped horn theory was bs. I only found a snippet of what he published, not the whole thing, and I did not find out who he was either.

In "Acoustics" by Leo Beranek, I had read that the size of the mouth of a horn had to be really huge just to output 20Hz-about the size of a walk-in fireplace in a castle, so how could a Danley DTS-10 horn, which is not even close to being that huge, act as a horn at even lower frequencies?

I do not know personally one way or the other if Danley tapped horns work as advertised or not.

Let me also add that when in my previous posting here I stated that a speaker that was designed for me by an acoustics professor went down lower in the bass than the speaker system I designed as a product, I was listening not to music or movie sound tracks, but to a sinewave signal generator. Nevertheless, to my ear the pure tones at or below 30 Hz did sound "musical" to my ear and would definitely be something I would like to hear reproduced if it was actually in music or a movie soundtrack I was listening to.

But if what I was actually hearing was not the fundamental but was harmonic distortion, then this all goes out the window.

 

[Hayabusa]

DC! I want my living room to have the same barometric pressure as the recording studio.

 

[audioresearch]

I was thinking of driving about an hour to where there is an Organ with a 16Hz pipe and listening to it but then it occurred to me that if I did hear the 16Hz pipe and it sounded "musical" to me, how would I know if it was the 16Hz I was enjoying or one of the harmonics? Same problem I guess listening to a speaker or headphone-again, how do I know it I am enjoying the fundamental or a harmonic? If I'm only hearing, say, the harmonics, then I don't really need a speaker to reproduce the fundamental, just the harmonics.

Doing something to attenuate out of existence the harmonics and leave only the fundamental is beyond anything I'm setup to do.

This problem seems to suffer from its own circle of confusion. Any opinions on this?

 

[Steve81]

Oh, in a similar vein, let me ask people's opinions on the Danley DTS-10 and the fact in general that Danley seems to think frequency reproduction down to something like 5 or 10 Hz is important. Do you think so? In fact, does anyone know if the DTS-10 or any other Danley speaker being sold really outputs loud enough spl at subsonic frequencies to even be considered loud enough to make a difference?

Josh Ricci measured the DTS-10 once upon a time, fwiw. Data-bass seems dead these days, but one can pull up a bit of info from the web archive at least.



As to whether I think reproduction of 5-10Hz is important, not particularly. YMMV though.

 

[Ken Tajalli]

We are getting abit side tracked.
But I just remembered something:
- Once in a hifi exhibition, in Wilson Audio room, I believe it was the Yvettes playing.
The guy from Wilson said "To show how deep the Yvettes can go, listen to this track" . It was an organ playing. At times, all we got was an ear-popping effect while the windows and the ceiling tiles were rattling!
The guy came back and said "you could tell the speakers were reproducing the low notes!" pointing to the ceiling with a grin on his face.

 

[OldHvyMec]

The term "Sub" is what you can't hear, but is felt, the term "BASS" is inclusive of both "felt" and what can be heard. Some people can hear
lower frequencies and I KNOW many are DEAF to the effects and the damage that has already happened. OSHA standards are published
for all to read and see.

What you are describing is 30hz and up accompanied by DEcoupling the bass from the domiciles' walls, floors or ceilings, with springs, pods
or air ride. If they are hung from the ceiling via chains/cables and springs that works too according to my experience.

Spikes do not work. Period, there is a reason why power plants are on isolators, springs and air bellows or air bags, they WORK.

I use LPs and hit 29hz with no tracking errors. Try that, not being decoupled or without at least a 40hz rumble filter flipped on.

If you're looking for lower measured distortion vs what you can actually hear the difference in, that is two different things. I found by lowering
250hz and < distortion to less than 5% everything cleans up in a treated room. Untreated all bets are off. I use Helmholtz resonators for peaks
and proper placement with "ENOUGH" 12" driver units to smooth the bass response. I use 6 OB 12" servos in about 300sf of floor space. 6 to
8 adjustable resonators Everything will fall into place in a normal rectangle room with 8 foot or taller lids. LPs are a breeze with servo bass and
a mechanically tuned room.

It's very easy to listen to servo bass without the fatigue a lot of over pressured rooms have. The second option is to make sure the ROOM is vented not IB
Sealed rooms SUCK, from my experience, BUT a servo bass system will load the room a lot different.

I can get VERY close with putty pinching passive radiators for LPs or the lowest possible FR without BOOM. One or the other BUT I can't have
both without a rumble filter and the lower FR.

Servo is pretty friggin' cool for the neighbors too. My garage set up went from leaving waves in the neighbors pool to a gentle up and down motion.
The pool water was ruining my tomato plants by the fence.

 

[Chrispy]

As deep as you wish it to be for your purposes, or what level of distortion you find acceptable (and at what spl).....not everything played back is acoustic music either.

 

[GXAlan]

20Hz to 20kHz is more than you need. That’s what we can hear not what is found in music.

While you can find organ music that goes down below 20 Hz, I cannot say that I routinely listen to music containing pipe organs. I do listen to piano.

Then, thinking about pianos, how many pieces use the very lowest or very highest note of the piano? It’s actually quite rare to use A0 but two mainstream pieces I know of are

• The Bells of Notre Dame from the Disney movie The Hunchback of Notre Dame.
• The Heart Asks Pleasure First from the movie The Piano.

But these are movie soundtracks, so you get to take advantage of LFE channel delivering that lowest note

Chopin’s Fantasie Impromptu goes down to 35 Hz. So in my mind, getting down to 35-40 Hz is full range for my music and compromises can be made because the question that then arises is if giving up some bass extension results in a better speaker elsewhere?

On the other hand, bass for movies is unlimited in appetite. This doesn’t mean that you need high SPLs just low extension.

Gran Turismo, the movie, is mediocre story telling but a sonic extravaganza. I saw it in “4DX” 6 axis motion which was great as well. I imagine tons of bass helps with the visceral element.

In Top Gun: Maverick, when Darkstar fires its afterburners, you need a lot of extension to replicate the feeling you get at an airshow.

THE REAL QUESTION
Once Dirac ART and Trinnov Waveforming are in play, don’t we want our main speakers to go as deep as the lowest room node so we have the ability to actively manipulate the room sound?

In that case, since positioning a subwoofer in every region of the room is harder than going with slightly larger full range speakers, the advice may be very different.

 

[Ken Tajalli]

So if everything even above 40Hz in some "song" is made of sound effects or synthesized sounds, is it still music?
Don't know why even bother responding to these threads.. just leave the standard link here:

Err!?
sound effects can be any frequency, obviously, I said below 40Hz is sound effects, well mostly.
In my native language, we have a saying: " Walnuts are round, but not anything round is a walnut".

 

[hege]

Err!?
sound effects can be any frequency, obviously, I said below 40Hz is sound effects, well mostly.
In my native language, we have a saying: " Walnuts are round, but not anything round is a walnut".

Maybe language barrier then, but lots of music have 30Hz content and even lower. It's silly to call it as some "sound effect" when it's clearly a part of the music (and not say some unintended microphone rumble). Whether 30Hz or 15kHz is "needed" for enjoyment, it's a completely personal issue.

 

[Sokel]

Depends what are you listening too.
Classical goes low,mainly to 30Hz,as well as mainstream (Evanescence new album has some good 30Hz hits).
Organ goes even lower.

The thing is that it has to be done well for some music,you can't integrate a sub 2m away from mains crossed at 100Hz if you listen to opera for example,baritones will sound weird.