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Topic: APO filter measurement (Read 4763 times) previous topic - next topic

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  • Juha
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APO filter measurement
Bumped into system-wide parametric equalizer for Vista/Windows 7/8 @ http://sourceforge.net/projects/equalizerapo/ and after quick look I extended it for RIAA EQ so that vinyls can be listen through PC w/o additional RIAA pre-amplifier/software.

As the APO filter is realtime, I need some software for to measure the filter output. Equalizer APO is recommended to be used in conjunction with Room EQ Wizard (http://www.hometheatershack.com/roomeq/) so, before registering for download, does anyone know if measures can be done using it only.

All suggestions on other suitable software are welcome.


Juha





  • DVDdoug
  • [*][*][*][*][*]
APO filter measurement
Reply #1
I can't answer your question, but...

I wouldn't recommend connecting a phono cartridge to the mic input on a soundcard.  If you do I wouldn't be too picky about getting the RIAA equalization "perfect".   

Phono cartridges are designed for a 47k-Ohm load.  I think most soundcard mic inputs are around 5k-Ohms.    That's going to affect frequency response, and different cartridges will be affected differently.  The XLR mic input on an audio interface or mixer is going to be even lower impedance.

Soundcard mic inputs put-out 5V to power electret condenser mics.  I don't know what the 5V "bias" does to a phono cartridge, but I'm sure it's not good.  Again, different cartridges may be affected differently...  I wonder if you can see the stylus move when feed-in 5V and use cartridge as a "motor"????

Some mic inputs are mono.  And, the mic-preamps in most consumer soundcards are low quality (noisy & maybe rolled-off high & low frequencies).    Since they are the wrong interface for any good studio/performance microphone (low-impedance balanced with an XLR connector) I consider the mic input useless for anything except gaming or communications.
  • Last Edit: 10 September, 2013, 07:50:49 PM by DVDdoug

  • Juha
  • [*][*][*][*][*]
APO filter measurement
Reply #2
I can't answer your question, but...

I wouldn't recommend connecting a phono cartridge to the mic input on a soundcard.  If you do I wouldn't be too picky about getting the RIAA equalization "perfect".   

Phono cartridges are designed for a 47k-Ohm load.  I think most soundcard mic inputs are around 5k-Ohms.    That's going to affect frequency response, and different cartridges will be affected differently.  The XLR mic input on an audio interface or mixer is going to be even lower impedance.

Soundcard mic inputs put-out 5V to power electret condenser mics.  I don't know what the 5V "bias" does to a phono cartridge, but I'm sure it's not good.  Again, different cartridges may be affected differently...  I wonder if you can see the stylus move when feed-in 5V and use cartridge as a "motor"????

Some mic inputs are mono.  And, the mic-preamps in most consumer soundcards are low quality (noisy & maybe rolled-off high & low frequencies).    Since they are the wrong interface for any good studio/performance microphone (low-impedance balanced with an XLR connector) I consider the mic input useless for anything except gaming or communications.


Sorry to say but your reply was very whimsical 

Anyway, I already found proper software for measures I needed.


Juha