Graphic Equaliser

Comments

• Unknown

  July 2000

  : I am wondering if anyone out there has atempted to implement a Graphic EQ, like the one in WinAMP, with the coloured bars?
  
  :
  
  : Thnx in advance.
  
  
  
  
  
  It is called a "Audio Spectrum Analyzer" that uses Fast Fourier Transforms.....email me and I will point you in the right direction.
  
  
  
  
  
• Unknown

  October 2000

  Please send me Vbcode for Graphic Equaliser
  
  
  
• akasha

  October 2001

  : : I am wondering if anyone out there has atempted to implement a Graphic EQ, like the one in WinAMP, with the coloured bars?
  : :
  : : Thnx in advance.
  :
  :
  : It is called a "Audio Spectrum Analyzer" that uses Fast Fourier Transforms.....email me and I will point you in the right direction.
  :
  :
  : Could You please point me to the right direction too?
  
  
  
• elechi

  April 2002

  : : : I am wondering if anyone out there has atempted to implement a Graphic EQ, like the one in WinAMP, with the coloured bars?
  : : :
  : : : Thnx in advance.
  : :
  : :
  : : It is called a "Audio Spectrum Analyzer" that uses Fast Fourier Transforms.....email me and I will point you in the right direction.
  : :
  : :
  : : Could You please point me to the right direction too?
  :
  :
  :
  
  hey? where is everyone going? "Audio Spectrum Analyzer" is not a Graphic Equalizer!!! the first displays the Dancing Bars. the other is a DSP.
  
  
• Tomy

  April 2002

  There are 2 ways to make a graphic EQ
  
  1 Implement a set of hi/lowpass-filters. These split the signal in 2: a part with the higher tones, and a part with the lower tones. If you want a 5-band EQlike on 50, 200, 800, 3200 & 12800 Hz, you implement a filter on 6400 Hz (log-center of 3200 & 12800), boost the upper part with the level for 12800 Hz, and send the lower part to a 1600 Hz filter, boost the upper part,...
  
  This technique is pretty fast (if you use the right filters) but the noise-level gets boosted every stage.
  
  2 Implement a set of bandpassfilters, 1 low- & 1 highpassfilter. Apply them on the source signal if they are active (Gain != 0db)
  
  This technique is also reasonable fast, the noise-level stays low, but the filters are hard to implement since they do not fit each other automatically.
  
  3 You could do an FFT & IFFT: Dont ! This is slow and not easy to implement.
  
  : I am wondering if anyone out there has atempted to implement a Graphic EQ, like the one in WinAMP, with the coloured bars?
  :
  : Thnx in advance.
  :
  :
  :
  
  
• elechi

  April 2002

  : There are 2 ways to make a graphic EQ
  :
  : 1 Implement a set of hi/lowpass-filters. These split the signal in 2: a part with the higher tones, and a part with the lower tones. If you want a 5-band EQlike on 50, 200, 800, 3200 & 12800 Hz, you implement a filter on 6400 Hz (log-center of 3200 & 12800), boost the upper part with the level for 12800 Hz, and send the lower part to a 1600 Hz filter, boost the upper part,...
  :
  : This technique is pretty fast (if you use the right filters) but the noise-level gets boosted every stage.
  :
  : 2 Implement a set of bandpassfilters, 1 low- & 1 highpassfilter. Apply them on the source signal if they are active (Gain != 0db)
  :
  : This technique is also reasonable fast, the noise-level stays low, but the filters are hard to implement since they do not fit each other automatically.
  :
  : 3 You could do an FFT & IFFT: Dont ! This is slow and not easy to implement.
  :
  : : I am wondering if anyone out there has atempted to implement a Graphic EQ, like the one in WinAMP, with the coloured bars?
  : :
  : : Thnx in advance.
  : :
  : :
  : :
  :
  :
  Yes I am trying to implement one using FFT & IFFT in Visual Basic!!!
  
• Tomy

  April 2002

  The reasons why you should not use FFT are
  
  1 FFT is SLOW because it is a comlplex algorithm
  
  2 FFT is SLOW because it calculates too much unnecesseary frequency-amplitudes. Our ear hears frequencies in a logaritmic order: eg. we experience 100Hz & 200 Hz as the same distance between 200 Hz & 400 Hz. If you use FFT with base-frequency of lets say 100 Hz, you get 100, 200, 300, 400, ... up till 22100 Hz.
  Result: bad resolution in the low registers & too much information for the highest tones. Solution for the lower frequencies: increase the block-size. But: then the latency increases & the calculation-time gets longer & the resolution for the higher frequencies gets even bigger. So this is no solution at all for any adio-related application !
  
  So: you could use it because you found a FFT-library on the web and want to check it out, but if you get serious about audio...