Generating negative harmonics
in [DSP]
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From: jungledmnc on 16 Mar 2010 15:52 Hi there, using waveshaping we can generate odd harmonics, right? Using some tricks like adding square we can have even harmonics. Is there a way to get negative harmonics? E.g. Sampling rate 44100, someone feeds it with 1kHz, I want to get 500Hz, or 250Hz for example. I have no idea if it isn't completely useless, but it may be worth experimenting with :). Thanks in advance!
From: Richard Dobson on 16 Mar 2010 16:12 On 16/03/2010 19:52, jungledmnc wrote: > Hi there, > > using waveshaping we can generate odd harmonics, right? Using some tricks > like adding square we can have even harmonics. > Is there a way to get negative harmonics? E.g. Sampling rate 44100, someone > feeds it with 1kHz, I want to get 500Hz, or 250Hz for example. > I have no idea if it isn't completely useless, but it may be worth > experimenting with :). > > Thanks in advance! They are called "subharmonics" (Google is your friend, etc); I have also seen them called "undertones" though that is much less common. Richard Dobson
From: Tim Wescott on 16 Mar 2010 16:41 jungledmnc wrote: > Hi there, > > using waveshaping we can generate odd harmonics, right? Using some tricks > like adding square we can have even harmonics. > Is there a way to get negative harmonics? E.g. Sampling rate 44100, someone > feeds it with 1kHz, I want to get 500Hz, or 250Hz for example. > I have no idea if it isn't completely useless, but it may be worth > experimenting with :). > > Thanks in advance! What you want from the subharmonics makes a lot of difference to how you may generate them. You could phase lock to a carrier, if it's well defined. You could use pitch shifting, if you're working with instruments or voice. You could use some bizarre parametric amplifier approach if you -- well, I don't know _why_ you'd want to do that! -- Tim Wescott Control system and signal processing consulting www.wescottdesign.com
From: Vladimir Vassilevsky on 16 Mar 2010 16:50 Tim Wescott wrote: > jungledmnc wrote: > >> Hi there, >> >> using waveshaping we can generate odd harmonics, right? Using some tricks >> like adding square we can have even harmonics. >> Is there a way to get negative harmonics? E.g. Sampling rate 44100, >> someone >> feeds it with 1kHz, I want to get 500Hz, or 250Hz for example. >> I have no idea if it isn't completely useless, but it may be worth >> experimenting with :). >> >> Thanks in advance! > > > What you want from the subharmonics makes a lot of difference to how you > may generate them. > > You could phase lock to a carrier, if it's well defined. > > You could use pitch shifting, if you're working with instruments or voice. > > You could use some bizarre parametric amplifier approach if you -- well, You could divide a frequency using a counter. > I don't know _why_ you'd want to do that! That used to be a common approach in the electronic music instruments before introduction of DSPs. Vladimir Vassilevsky DSP and Mixed Signal Design Consultant http://www.abvolt.com
From: Nils on 16 Mar 2010 17:02
Vladimir Vassilevsky wrote: > > That used to be a common approach in the electronic music instruments > before introduction of DSPs. > Absolutely. I'd like to add that subharmonics have been the way to bring color into the sound of the trautonium. If you have seen classic movies from the 60th and 70th you most probably konw the sound of it. Worth checking out: http://de.wikipedia.org/wiki/Trautonium Also: http://en.wikipedia.org/wiki/Oskar_Sala (the engish wiki-page is seriously lacking information. That guy was a genius). Cheers, Nils |