? re: digitech echo plus (bit rate)?

[Charles Zwicky <cazwicky@earthlink.net>]

The major difference between 8 bit and 24 bit word width as it 
applies to audio fidelity is in the dynamic range and signal to noise 
ratio.  With an 8 bit data path you can achieve about 48dB of dynamic 
range and with a 24 bit system 144 dB .  In a looper, the signal to 
noise and dynamic range will degrade by about 6dB  each time the 
signal is recirculated (the HOLD function will simply keep the data 
in memory and no further degradation will occur). The old EH and 
Digitech DDL loopers also used a variable sampling rate, which is how 
the pitch of the loop is changed.  In digital audio the signal to 
noise ratio and distortion are improved by about 3dB each time you 
double the sampling rate. A modern device wil typically sample the 
audio at 44,100 samples per second, and the digitech and EH boxes can 
sample  at rates as low as 3-6kHz, you can hear the aliasing (crunchy 
HF didsortion) readily at those sample rates.




>ok, i was watching a youtube vid on a guy demoing a digitech echo 
>plus (is that the pds 8000? not sure).
>anyway, the things it could do were kind of cool 8 sec of delay, 
>came out in the late 80's (i know frisell has used one in place of 
>his old EH 16 DDL),...
>
>he was showing the main features of it, slapback echo (he seemed to 
>be into the "rockabilly sound"-played some real twangy reverse strat 
>so he looked like a sort of righty hendrix, he was kind of funny), 
>and i think he did a longer echo demo, then did a bit showing the 8 
>sec sample format (he of course didn't show enough of that, which i 
>wanted to see!!!!). someone on another forum i check (the gear page) 
>was talking about this unit can do the funny pitch changes by 
>playing w/ the time knob (i think?)-and said that's one thing the 
>frisell exploits greatly.
>anyway, my question:
>the echo plus demo funny man said-that the device uses 8-bit vs. the 
>nowadays most digital pedals use 24-bit. could someone explain this 
>to me. i mean sound-wise i thought the echo plus sounded great. i 
>know there's been talk of this before here, (i probably tuned out), 
>i'm just going on what i heard heard from the vid (i'm sure not 
>pristine quality) but it all sounded good to me....
>
>thanks,
>s---
>www.myspace.com/scotthansen


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