I am doing a software project about a ten-band graphic equalizer. Is there any solutions about how to design it? Currently, I have the following ideas: 1.Use FFT, apply different gains to each frequency bin. But for low frequency band like 31.25Hz, 62.5Hz, 125Hz, there are few frequency bins even using large length FFT. The frequency precision is roughly influencing. 2.Use FIR filter bank. Design ten band-pass filters, apply gains in each band, then sum then together in time domain. But still for low frequency band like 31.25Hz, 62.5Hz, 125Hz, the filter length will be very very large. I don't know how to cope with this problem. 3.Use IIR filter bank. Which may greatly reduce the filter length. But another concern appears. IIR filter is not a linear phase filter. Furthermore, it may unstable after processing many audio frames. Hope DSP experts can help me. :) Thanks a lot! This message was sent using the Comp.DSP web interface on www.DSPRelated.com
How to design a graphic equalizer
Started by ●August 27, 2005
Reply by ●August 27, 20052005-08-27
Did you see the responses you got to the last time you posted this? Since you are using DSPRelated, take a look at http://www.dsprelated.com/showmessage/40829/1.php -- Jon Harris SPAM blocker in place: Remove 99 (but leave 7) to reply "dingke1980" <dingke1980@hotmail.com> wrote in message news:ke-dnfBT26Oi3o3eRVn-jw@giganews.com...> > I am doing a software project about a ten-band graphic equalizer. Is there > any solutions about how to design it? Currently, I have the following > ideas: > > 1.Use FFT, apply different gains to each frequency bin. But for low > frequency band like 31.25Hz, 62.5Hz, 125Hz, there are few frequency bins > even using large length FFT. The frequency precision is roughly > influencing. > > 2.Use FIR filter bank. Design ten band-pass filters, apply gains in each > band, then sum then together in time domain. But still for low frequency > band like 31.25Hz, 62.5Hz, 125Hz, the filter length will be very very > large. I don't know how to cope with this problem. > > 3.Use IIR filter bank. Which may greatly reduce the filter length. But > another concern appears. IIR filter is not a linear phase filter. > Furthermore, it may unstable after processing many audio frames. > > Hope DSP experts can help me. :) > > Thanks a lot! > > > This message was sent using the Comp.DSP web interface on > www.DSPRelated.com