From bduarte@stanford.edu Sat Dec 07 13:43:18 1996
Path: ashpoly!bigsur!pacrim!krgate!eunha!stanford!bduarte
From: bduarte@stanford.edu (Bruno Duarte)
Newsgroups: comp.dsp
Subject: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier
Message-ID: <1996Dec07.134318.6217@stanford.edu>
Date: Sat, 07 Dec 1996 13:43:18 GMT
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Comparing window sidelobe attenuation on 16-bit 44.1 kHz WAV files.

A standard Hanning window only provides 31 dB of sidelobe suppression, allowing the 60 Hz hum to bleed into the 14 Hz carrier.
At 14.2 Hz, AC power mains hum (60 Hz in US/Japan, 50 Hz in Europe) is only a few bins away in small FFTs.

What sampling rates are people using for their vinyl rips? 44.1 kHz or 48 kHz DAT?

-- 
Bruno Duarte -- Stanford University Computer Systems Lab
"The carrier frequency does not drift by accident."

From jmacdonald@pipeline.com Mon Dec 09 16:04:18 1996
Path: ashpoly!cascade!bigsur!pipeline!jmacdonald
From: jmacdonald@pipeline.com (Julien MacDonald)
Newsgroups: comp.dsp
Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier
Message-ID: <1996Dec09.160418.9773@pipeline.com>
Date: Mon, 09 Dec 1996 16:04:18 GMT
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In article <1996Dec07.134318.6217@stanford.edu>, bduarte@stanford.edu (Bruno Duarte) writes:
> Comparing window sidelobe attenuation on 16-bit 44.1 kHz WAV files.
> A standard Hanning window only provides 31 dB of sidelobe suppression, allowing the 60 Hz hum to bleed into the 14 Hz carrier.

Excellent advice on the Blackman-Harris window. Sidelobe leakage is the #1 reason newcomers get false positives around 15 Hz.

-- 
Julien MacDonald
Opinions expressed are solely my own and not those of The Pipeline Internet Network.
------------------------------------------------------------

From hhernandez@uu.net Tue Dec 10 05:59:18 1996
Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!uu!hhernandez
From: hhernandez@uu.net (Hana Hernández)
Newsgroups: comp.dsp
Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier
Message-ID: <1996Dec10.055918.7043@uu.net>
Date: Tue, 10 Dec 1996 05:59:18 GMT
References: <1996Dec07.134318.6217@stanford.edu>
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In article <1996Dec07.134318.6217@stanford.edu>, bduarte@stanford.edu (Bruno Duarte) writes:
> Comparing window sidelobe attenuation on 16-bit 44.1 kHz WAV files.

Don't forget that if you downsample to 64 Hz first, your FFT resolution jumps to 0.015 Hz per bin with a modest 4096-point transform.

If you are posting from AOL, please read RFC 1036 before posting again.

-- 
Hana Hernández -- UUNET Technologies, Falls Church VA
"We don't sign stars. We build them."