[sdiy] Harmonic bandwidth

[Scott Gravenhorst]

"Needham, Alan" <Alan.Needham at centrica.com> wrote:
>-----Original Message-----
>From: synth-diy-bounces at dropmix.xs4all.nl
>[mailto:synth-diy-bounces at dropmix.xs4all.nl] On Behalf Of karl dalen
>Sent: 10 January 2008 10:52
>To: synth-diy at dropmix.xs4all.nl
>Subject: SV: RE: [sdiy] Harmonic bandwidth
>
>-snip-
>Actually its ridiculously to try to verify this small phase responses
>with
>speakers. Just twist your head slightly as some one here previously
>mentioned.
>-snip-
>
>KD
>__________________________________________________________________
>
>I don't agree with that - sure there are phase shifts inherent in the
>speaker design (and amp and preamp), but they will be a constant for any
>one speaker so that will result in, say, a 10 degree shift at the 10th
>harmonic of a hypothetical waveform. Does this mean nobody really knows
>what a square wave sounds like?
>
>In my humble opinion we are venturing into "gold-plated mains connector"
>territory here.
>	Alan

At the very least, I believe we can say that no two people hear exactly the same thing,
even given the same signal through the same equipment - due to differences in hearing.
 Sort of like the "does yellow look to you the same as yellow looks to me?".  

So I think the answer is "no", nobody really knows what a square wave sounds like. 
Within our own hearing domain, we learn to recognize what we hear as this or that
waveform and can repeatedly identify it as such.

However, within the domain of any individual's hearing, according to theory, we should
not be able to hear the difference between two signals with the same harmonic
components when harmonic phase relationships are constant, but different between two
signals.

For me, the puzzle is why when we create waveforms digitally, are we sometimes able to
hear this difference which counters the theory.  I certainly do not have the equipment
to do this with purely analog electronics, but that would be an interesting experiment
to use for comparison with the digital methods we've tried.

-- ScottG

-------------------------------------------------------------

-- Scott Gravenhorst
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