Topic: 24 bit & Microphone specs?

[ethan]

From my understanding the sample rate defines what the frequency spectrum of the recording is and bit depth define the dynamic range. I can totally understand recording at higher sample rates but I'm curious about whether there is any real advantage to increased bit depth other than being able to run a variety of word length reduction processes to lower the noise floor.

The reason I as this is I was looking at the Spec's for my DPA 4011's.  The specs clearly list a Dynamic Range of 97dB. If the mics can only do 97dB what does the 24 bit bit depth buy you?

-e

[Wiggler]

I found this info on bit rate and sampling rate on another site.
http://forums.audioreview.com/showthread.php?t=4214

I'm posting a quick explaination for the digital jargon that one constantly hears: Bit Rate Resolution & Sample Rates. This post is intended for all who want a better understanding of what these terms actually mean. I recently read up on these definitions to be more informed in the misleading marketing world and to better understand the more esoteric posts on this site. All audiophiles and techies, please tweak this post or add some more insight.

Digital Audio is measured in two ways: Bit Rate Resolution and Sample Rate.

Sample Rate is the number of samples per second taken of the audio. 1Hz = 1 sample per second. RedBook CD (RBCD) is 44.1kHz = 44,100 samples per second.

Bit Rate Resolution is the digital word length of each sample. This determines how precise each sample is. Think of it this way. You can explain last night's concert more precise using 100 words rather than using 20 words. RBCD bit rate resolution is 16bit which gives a 65,535 word length. If a certain sample takes more than 65,535 words to describe than the sample will lose some information which results in distortion. The precision difference with bit rate is noticeable when you realize that most internet audio streams are at 8bit and digital telephones are at 4bit. Background noise is associated with lower bit rates.

So......If one second of audio is analogous to the view of your backyard, the RBCD digital representation of your backyard would be akin to looking at it through a screen door with 44,100 holes in the screen and 65,535 words or colors within each screen hole.

[JasonSobel]

well, in theory, a 16 bit recording can have a dynamic range of 96dB, and a 24 bit recording can have a dynamic range of 144dB.  in practice, this is limited by equipment specs (preamps, A/D's, etc, etc...) to somewhere around 110 to 120 dB for a 24 bit device.

that said, I'd be surprised if any concert had a noise floor lower than -40 or -50 dB.  So, from a practical standpoint, any concert is only going to have a dynamic range of 40 to 50 dB.

When considering 24 bit recording, I'd say the resolution  of the recording is just as important, if not more-so, than the dynamic range.  with 24 bit recording, there is more information at each sample, so each sample is a more accurate representation of the analog wave entering the A/D converter.  because of this, 24 bit recordings can seem much more natural and lifelike.  It's hard for me to describe in words the difference in sound between 16 and 24 bit recordings, but the difference is definitely there.