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Re: Sample Rate Conversion

Subject: Re: Sample Rate Conversion
From: Vicki Powys <>
Date: Sun, 09 May 2004 09:22:58 +1000
Walt wrote about Lang's insect recordings:

> I've put up what I got off a copy of Lang's file:
> Peak 4.03:
> m("44khz_peak.aif","//madranis.home.mindspring.com/insect");">http:
> Spark XL 2.81:
> m("44khz_spark.aif","//madranis.home.mindspring.com/insect");">http:
> Soundhack (osX version 0.892):
> m("44khz_shak.aif","//madranis.home.mindspring.com/insect");">http:
> The original Lang sent me:
> m("48khz.aif","//madranis.home.mindspring.com/insect");">http:


I've downloaded these files and had a listen.  My hearing is fairly OK for
higher frequencies.  I was listening through Sennheiser HD 570 headphones
via my iMac.

The original sounded good
Peak sounded quite a lot thinner than the original
Soundhack sounded exactly the same as the Peak file
Spark sounded noticably thinner than either Peak or Soundhack

Vicki Powys
Australia









on 9/5/04 1:49 AM, Walter Knapp at  wrote:

> From: Lang Elliott <>
>> 
>> 
>> Going the analog route, unfortunately, means playing each file in real time.
>> I really can't afford to do that.  ProTools will just have to do for now.
>> 
>> I wonder if enough folks in this group would like to have a copy of my 48Khz
>> test file, which is an insect singing at around 12kHz. I think it is really
>> demanding of any sample rate converter going to 44.1.
>> 
>> Let me know if there's some interest and I'll post a wave file on my web
>> site.
> 
> I've put up what I got off a copy of Lang's file:
> Peak 4.03:
> m("44khz_peak.aif","//madranis.home.mindspring.com/insect");">http:
> Spark XL 2.81:
> m("44khz_spark.aif","//madranis.home.mindspring.com/insect");">http:
> Soundhack (osX version 0.892):
> m("44khz_shak.aif","//madranis.home.mindspring.com/insect");">http:
> The original Lang sent me:
> m("48khz.aif","//madranis.home.mindspring.com/insect");">http:
> 
> I should note I also found a slight DC offset in the original, and
> removed that before conversion. DC offset introduces it's own errors and
> I routinely remove that.
> 
> Also, my system only outputs at 44k, so even listening to the original
> it was already resampled. Spark and Peak played the original the same.
> Sonograms showed in addition to the high frequency call centered on
> about 12khz a band at about 5khz (the raspy sound) and a bunch of low
> level sound below 170hz. The sonogram of the peak conversion does show
> some very low level sound below the 5khz band.
> 
> Spark has batch capabilities, soundhack does not. I used best settings
> in each, Spark was doing the math in 32bit floating point, not sure on
> the others. Each has variations in settings available, and those do
> change the outcome.
> 
> I have such lousy hearing at these high frequencies I was having to
> really boost volume. To me Peak and the original sound about the same,
> but that could be my hearing. Spark is different. I also did Soundhack
> as well, somewhere between peak and spark. I had my son listen to them
> all, he can listen to the high frequency at normal listening settings.
> He said there was little difference to him.
> 
> Walt
> 
> 
> 
> 
> 
> 
> 
> "Microphones are not ears,
> Loudspeakers are not birds,
> A listening room is not nature."
> Klas Strandberg 
> Yahoo! Groups Links
> 
> 
> 
> 
> 
> 



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