linuxaudio.org

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On Mon, Dec 31, 2012 at 5:44 PM, Tim E. Real  wrote:
> Just an offside comment and question:

quoted text
>

> I've repaired a lot of subwoofers.

> After repair we had to let them run by themselves with audio.

>

> I noticed a very strange phenomenon with all of them.

>

> When you listen to a subwoofer all by itself, the music which

>  comes out of it seems to be noticeably off-key, until you

 turn up the rest of the audio system.

quoted text
>

>

The way our ears work, what frequency we actually hear shifts slightly with

intensity.  There is a great book on acoustics by F. Alton Everest that

goes into this a bit in one of the earlier chapters.  I am still reading

through all of it, but it is an interesting phenomenon.  Pitch is in

actuality a subjective form of Frequency, not objective, and this is

reflected in this phenomenon.

> The level of sound affects the perception of pitch. For low frequencies,

the pitch goes down as the level of sound is increased. At high

frequencies, the reverse takes place=97the pitch increases with sound level=

.
> Everest, F. Alton (2000-09-22). Master Handbook of Acoustics (Kindle

Locations 1553-1555). McGraw-Hill. Kindle Edition.
There is a nice experiment involving two oscillators they use to

demonstrate this.  The book is well worth the money if you can get it and

read English natively(Not sure what translations exist or how good they

are).  I am still working my way through it but it will likely take me two

or three times through before I fully understand most of it.
            Seablade
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On Mon, Dec 31, 2012 at 5:44 PM, Tim E. Real <termtech@rogers.com> wrote:
Just an offside comment and question:
I've repaired a lot of subwoofers.

After repair we had to let them run by themselves with audio.
I noticed a very strange phenomenon with all of them.
When you listen to a subwoofer all by itself, the music which

=A0comes out of it seems to be noticeably off-key, until you=A0=A0turn up the rest of t=

he audio system.
The way our ears work, what frequency we act=

ually hear shifts=20

slightly with intensity.=A0 There is a great book on acoustics by F. Alton

 Everest that goes into this a bit in one of the earlier chapters.=A0 I am

 still reading through all of it, but it is an interesting phenomenon.=A0=

=20

Pitch is in actuality a subjective form of Frequency, not objective, and

 this is reflected in this phenomenon.> The level=20

of sound affects the perception of pitch. For low frequencies, the pitch

 goes down as the level of sound is increased. At high frequencies, the=20

reverse takes place=97the pitch increases with sound level.> Eve=

rest, F. Alton (2000-09-22). Master Handbook of Acoustics (Kindle Locations=

 1553-1555). McGraw-Hill. Kindle Edition. There

 is a nice experiment involving two oscillators they use to demonstrate=20

this.=A0 The book is well worth the money if you can get it and read=20

English natively(Not sure what translations exist or how good they=20

are).=A0 I am still working my way through it but it will likely take me=20

two or three times through before I fully understand most of it.<=

div>=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0 Seablade
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