MOTM

oops
i think i got over excited on that last post and didn't read it properly, so
repeat after me:

Eventide H949 Harmonizer

you can get them in the uk for around \ufffd250, the pitch can either be voltage
controlled or clocked via a VCO
i've got an H949 and i love it - i'm not too sure what facilities are
available on the H910 which is far cheaper on the s/h market
as far as i know, the H910 & H949 are analogue pitch shifters

cheers
paul (ducking this time)

----- Original Message -----
From: "paulhaneberg" <phaneber@...>
To: <motm@yahoogroups.com>
Sent: Monday, December 27, 2004 6:47 PM
Subject: [motm] Re: Pitch Shifter


>
>
> There is no such thing as an analog Pitch Shifter.  At least as far
> as I know.  I suppose one could be built if you could find a charge
> coupled bucket brigade type device capable of high enough quality,
> but that's unlikely.  All pitch shifters are digital and break the
> incoming signal into samples just like digital delays.  There are
> always trade offs involved in making a pitch shifter as well, as
> improved pitch accuracy and improved timing accuracy are somewhat
> mutually exclusive.
>
> I think what you are really looking for is a pitch shifter which can
> accept a control voltage to control the amount that the signal is
> shifted in pitch.  This is also difficult to accomplish.  Most
> Digital Delay devices which are capable of analog voltage control
> actually step between delay values rather than continuously changing
> value.  This tends to cause zipper noise.  In order to vary the
> delay (or the pitch) continuously the sample rate clock must be
> voltage controlled.  While not impossible, this is quite difficult.
> If you are sampling at 48 kHz which would give you a maximum input
> frequency of around 20 kHz, and then you wanted to either decrease
> the delay time or raise the pitch by two octaves, your sample rate
> clock would now be running at 192 kHz.  If you slow down below 48
> kHz you will lose high end response or generate some truly nasty
> artifacts, so the effective range is only about 2 octaves using
> modern converters if you want to be continuously variable without
> stepping.
>
> It may be possible to get more range with a delta/sigma scheme or by
> using a flash converter with a compander.  This is something I'm
> personally interested in exploring, as I'm interested in the musical
> applications of delay lines, but I haven't had time to play around
> with any kind of circuit design yet.
>
> The frequency shifter is another animal entirely.  The Encore
> Electronics module is quite wonderful, but as someone else pointed
> out a frequency shifter does not maintain the integer spacing of
> harmonics present in the input signal, so it really does not shift
> pitch.
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> Yahoo! Groups Links
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