linuxaudio.org

Rick Wright wrote:

quoted text
> david wrote:

>

>> Folderol wrote:

>>

>>> On Thu, 22 Feb 2007 13:48:04 -0600

>>> millward  wrote:

>>>

>>>> I've got a sound card capable of 96 bits, ( M-Audio audiofile 24/96 )

>>>> but my sound editor, Audacity for Linux, only goes up to 32 bits.

>>>> Is there a sound editor for Linux that can do higher than 32 bits?

>>>

>>>

>>> Maybe I'm missing something here, but what on earth does anyone need

>>> such high resolution for?

>>>

>>> ISTR The humble CD is recorded at 18bit. which is over 200,000:1 and

>>> more than 100dB. The orchestral dynamic range is I believe quoted at

>>> 90dB. I accept some extra headroom is nice, and the calculations aren't

>>> quite so simple, but even 32bit comes out at mind boggling 200dB.

>>

>>

>> I don't know about such things in the audio world, but in the world of

>> color photography, most professional digital equipment uses 48-bit color

>

> Yes, but this 48bit representation of color is just 16bit x3 colors

> [channels].  In other words the 48bit representation is 3 unrelated

> 16bit [channel] representations concatenated, one each for the 3 primary

> colors/CCD sensors.  The equivilent for audio would be just 16bit as

> there is only one channel.

Hmmm, wouldn't there actually be TWO channels for audio - stereo?
>> This is way outside the reproduction range of any photo

quoted text
>> printing/display technology. But even though a particular 48-bit color

>> might not be printable or displayable, it is still there. It can be

>> taken into consideration when doing color adjustments and image

>> filters. The end result is that when color depth is reduced to the

>> 24-bit color range that JPG uses - you get better and more accurate

>> color reductions.

>>

> Following from above, your final JPG color depth gets reduced to just

> 8bits per color which is why RGB uses values from 0-255.  8bits only has

> informaiton for 256 values.

That's right. But the more information you start with, the smarter the

reduction can be - particularly in areas where the 48-bit color value is

outside the 24-bit dynamic range. In photography, this means the

highlight and shadow areas. In the audio world, would mean this more

accurate renditions in the lowest and highest volume sounds? I don't know.
Depth reduction in color photography doesn't have to be a mindless

simple mathematical calculation, good software like Photoshop

(Windows/Mac) Bibble (Windows/Linux), Raw Therapee (Windows/Linux),

DCRaw (Linux) can do things more intelligently because they have more

information available to them when working with 48-bit color.
I think you can go even higher than 48-bit color in the professional

color world - I think high-end drum scanners scan at 64-bit color.
>> So I would think that working in higher bit-depths for audio would

quoted text
>> similarly result in better sounding audio when it's reduced to CD format.

>

> This is true, but as Folderol wrote, 32 bits should be *plenty* of

> dynamic range for audio.  In fact, it has been argued that ~22bits is

> sufficient as beyond this you get into the h/w noise floor, hearing

> limits, etc.

>

> (Any other experts out there, feel free to jump in if I'm wrong here...)

Yes, experts? I'm no audio engineer!
--

David

gnome@hawaii.rr.com

authenticity, honesty, community