Subject: Re: Frequency response was Re: [linux-audio-user] Audiophile CD's
From: Paul Winkler (pw_lists_AT_slinkp.com)
Date: Mon Jan 28 2002 - 20:47:18 EET
On Mon, Jan 28, 2002 at 06:00:59PM +0000, Steve Harris wrote:
> On Mon, Jan 28, 2002 at 12:49:01 -0500, Paul Winkler wrote:
> >
> > * Do you know for sure that the playback system doesn't produce
> > distortion below 20 kHz when faced with harmonic content at 32 kHz and
> > above? How can this be verified? I don't know how to do this on my own
> > system...
>
> You can either use band limited oscilator generation, or oversample and
> use a lowpass filter.
>
> If you didn;t do this though you will get prominent aliasing in the lower
> frequencies.
Yes, that answers my earlier question about digital test tone generation.
But that last question was about distortion in the (analog) playback
system - preamplifier, amplifier, speaker, etc.
I have been told (don't know if it's true) that this accounts for many
claims of hearing ultrasonic content, including the famous Rupert Neve
/ Geoff Emerick story, which is oft-repeated and rarely analysed.
This would mean that we could obtain equally good results by A) making
the entire recording/playback chain very linear up to very high
frequencies, or B) filtering out ultrasonics.
If this is the case, it's worth knowing, because B is a lot cheaper
and easier than A.
--paul winkler home: http://www.slinkp.com music: http://www.reacharms.com calendars: http://www.calendargalaxy.com
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