Help me understand audio buzz words...

[FrzzMan]

Well, I'm really a noob here, while reading the specs of the E-MU 0404 which I've just ordered, I don't fully understand what do they mean. So someone here please explain them to me, thanks.

The specs: http://www.emu.com/products/product....Specifications

- Bit Depths: 24-bit I/O, 32-bit processing <-- OK, I think more bits per sample mean the sample can contain more information, so the sound maybe more fidelity, correct me if I'm wrong. But, why 24-bit I/O but 32-bit processing??? So the data bandwidth is 24-bit, so how the sound processor process the data wit 32-bit.
- What is Dynamic Range?
- What is SNR?
- What is Impedance, I so them a lot in headphone and speaker specs, even amp and preamp... how is it affect sound?

More to come, stay tuned

 

[BillC]

Bit Depth/Processing: Extra bits in the processing mean more accurate results, fewer round off errors, overflows, etc.

Dynamic Range: the ratio between the largest and smallest allowable values. In audio, the space between the loudest and the softest sounds that can be reproduced.

SNR: Signal to Noise Ratio, Higher is better - meaning that there is less noise degrading the intended signal.

Impedance: a measure of how much voltage is required to push current through a load. So for a given voltage you create a lower current flow through higher impedance headphones. How this is related to the sound is a broader question than I want to tackle.

 

[Daroid]

Quote:

Originally Posted by FrzzMan Well, I'm really a noob here, while reading the specs of the E-MU 0404 which I've just ordered, I don't fully understand what do they mean. So someone here please explain them to me, thanks. The specs: http://www.emu.com/products/product....Specifications - Bit Depths: 24-bit I/O, 32-bit processing <-- OK, I think more bits per sample mean the sample can contain more information, so the sound maybe more fidelity, correct me if I'm wrong. But, why 24-bit I/O but 32-bit processing??? So the data bandwidth is 24-bit, so how the sound processor process the data wit 32-bit. - What is Dynamic Range? - What is SNR? - What is Impedance, I so them a lot in headphone and speaker specs, even amp and preamp... how is it affect sound? More to come, stay tuned

Bit depth: 24 bits means that there are 2^24 amplitude levels in a waveform sample thus providing smaller "steps" so it will meet the neighbor step more accurately than e.g. with 16 Bit. Scientific tests have shown that the ear doesn't detect more than 18 Bits.
Using 32 Bit or even higher bit-depths has it's advantages: You can apply DSP effects to the signal and it wouldn't run into problems (can't remember the term right now in English) but basically it can cause rounding problems to the samples if the waveform is DSP processed with the same bit-depth as the format already was.

Dynamic Range: Is expressed in it's wording - the dynamic range measurement defines the difference between the largest and smallest signal level.

Signal-noise ratio: A root mean square (RMS) calculation between the signal (sine wave, but it can be signal of any dynamic range) and noise floor. Given by: SNr= 20Log(signal/noise)

Impedance: Simple rule - Impedance is for AC circuits what resistance is for DC circuits. Think of a speaker. When it is passive (e.g. just a coil) and we don't consider temperature impact you can measure it's coil resistance.
Apply an AC signal to the coil and a membrane as if it was a speaker. Now the membrane also has an impact of this "resistance". So impedance is defined by resistance + reactance. Reactance is frequency dependent because it is either capacitive or inductive reactance. See: http://www.schoenbaumlab.org/nicoweb...e%20Reactance: and http://encyclopedia.laborlawtalk.com/Reactance