From: Don Pearce
Subject: Re: Acoustic Feedback reduction
Date: Wed, 15 Jan 2003 15:37:15 +0000
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On Wed, 15 Jan 2003 15:16:30 -0000, "Kevin Aylward"
>> Ok Phil
>> I borrowed a 5Hz frequency shifter form a sound reinforcement company.
>> We played the following notes concurrently on a synth.......
>> E - 2, B - 2 and E +1. For the unititated these are the low E on a
>> standard guitar, B a fifth up from this, then another E, 2 octaves
>> higher. We recorded it and have posted it here....
>> The file is called 5HzShift.wav The first 3 seconds are the 3 notes
>> played direct. The last 3 seconds are the same notes played through
>> the 5Hz shifter (we simply switched it on while holding the keys
>> We also did the same thing an octave lower (still nowhere near the
>> bottom of the music range) and the results were, as expected, even
>> worse. However typical PC speakers won't even reproduce it so it
>> seemed pointless posting it.
>Well, my crappy PC speakers certainly showed the difference.
>The reality is that you need to shift by a fixed ratio, not a fixed
>frequency,as in speeding/slowing a tape recorder.
As if proof were even needed - you have supplied it in spades!
Only one person around these parts who believed otherwise, but then of
course he is an expert - so what do we know? Sound obviously behaves
differently in the antipodes.