From agarcia@clari.net Tue Feb 22 14:34:58 1994
Path: ashpoly!cascade!mxgate!coyoacan!clari!agarcia
From: agarcia@clari.net (Anton García)
Newsgroups: comp.dsp
Subject: Question: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier
Message-ID: <1994Feb22.143458.2235@clari.net>
Date: Tue, 22 Feb 1994 14:34:58 GMT
Organization: ClariNet Communications Corp
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Comparing window sidelobe attenuation on 16-bit 44.1 kHz WAV files.

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.
A Kaiser-Bessel window with parameter beta = 8.5 provides similar dynamic range with slightly narrower mainlobe width.

Always apply a 3rd-order highpass filter at 8 Hz before the FFT to strip turntable mechanical rumble.

-- 
Anton García -- ClariNet Communications Corp
"Marcus is not one man."

From rmuller@ox.ac.uk Thu Feb 24 18:23:58 1994
Path: ashpoly!cascade!transat!eunet-de!hansebox!ox!rmuller
From: rmuller@ox.ac.uk (Raj Müller)
Newsgroups: comp.dsp
Subject: Re: Question: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier
Message-ID: <1994Feb24.182358.9640@ox.ac.uk>
Date: Thu, 24 Feb 1994 18:23:58 GMT
References: <1994Feb22.143458.2235@clari.net>
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In article <1994Feb22.143458.2235@clari.net>, agarcia@clari.net (Anton García) writes:
> Comparing window sidelobe attenuation on 16-bit 44.1 kHz WAV files.
> 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.

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

-- 
Raj Müller
Tape trading list upon request. SASE required for international mail.

From srodriguez@kth.se Sat Feb 26 02:29:58 1994
Path: ashpoly!cascade!transat!eunet-de!hansebox!kth!srodriguez
From: srodriguez@kth.se (Sergei Rodríguez)
Newsgroups: comp.dsp
Subject: Re: Question: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier
Message-ID: <1994Feb26.022958.8444@kth.se>
Date: Sat, 26 Feb 1994 02:29:58 GMT
References: <1994Feb22.143458.2235@clari.net>
Organization: Royal Institute of Technology, Stockholm
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In article <1994Feb22.143458.2235@clari.net>, agarcia@clari.net (Anton García) writes:
> Comparing window sidelobe attenuation on 16-bit 44.1 kHz WAV files.

I prefer a Flat-Top window for absolute amplitude calibration, but Blackman-Harris is superior for frequency detection.

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-- 
Sergei Rodríguez -- Royal Institute of Technology, Stockholm
"Row 14. No joke."