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equalisation (BFD like)???

Discussion in 'Desktop & Laptop Computers Forum' started by buns, Jul 14, 2003.

  1. buns

    buns
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    Just was wondering, tag have their very good software equalisation. Now it is only software..... is there any pc software that we could feed the LFE into via a sound card, do our analysis and apply equalisation and then feed it back out?

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  2. GaryRees

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    There are a few software analysers out there for measuring room acoustics which run through your PC. Some are free but the decent ones cost between 50 and 100 quid.

    Once you've analysed you're room, you then programe the processor to compensate for room acoustics. As far as I'm aware the processor then uses several different types of filter to attenuate whatever frequencies are causing resonances - a bit like a very a sophisticated parametric equaliser ( with frequency resolution of 1khz and a bandwidth adjustment of down to one-twenty-fourth of an octave. )

    So I suppose the answer is - yes you can analyse your room and speakers using your PC, but without the necessary software or firmware you cannot apply compensation.

    I think it's about time someone like M-Audio or RME brought out a dedicated audiophile home cinema soundcard with software that includes room equalisation and proper bass management.

    Check out this link for a good software analyser

    http://www.etfacoustic.com/
     
  3. buns

    buns
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    sorry, i know all about the tag and eft stuff..... what im asking is about the pc compensating if you dont have a tag! so im guessing thats a no then.....

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  4. GaryRees

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    It's a no as far as I know - but if someone knows of anything - I'd be interested to Know - no? :D
     
  5. kryten

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    AFAIK there is no generic PC solution.

    Whilst your nice shinny P4 3Ghz seems very fast, its a general purpose CPU and not up to the job of making complex calculations on 6 channels in real time (the resolution is usually 1Hz not 1kHz as stated above as room correction really only works well below 200Hz or so).

    A few years ago I was working on a system that was intended allowed real time EQ etc of just 2 channels (in line with an optical feed, between CD output and DAC input) and it just wasn't feasible without custom chips - Custom DSPs are really the only way to achieve real time processing of this type.

    Just think what framerate you'd get on Quake 3 if the CPU had to do all the 3D calculations the custom GPU on your nice ATI-Nvidia-Whatever mega graphics card is currently doing.

    Doing some basic maths, and allowing for the fact that you really need to be upsampling to at least 96kHz to avoid the artifacts you would generate if only using 44kHz (and probably 24bit too for precision), we end up with processing 96,000 samples per second across 6 channels for home cinema. That means you need to get through 576,000 24bit samples EVERY SECOND.

    Believe me, even for the fastest PC CPU, that's an awful lot!
     
  6. buns

    buns
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    Actually im only concerned about one channel, the sub.

    So this is a niche in the market then...... if the cpu is incapable to do this, then a custom card to do it...... interesting though, shame im not in a position to do anything about it. :(

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  7. Jeff

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    You can do real time EQ of 2 channels with a bog standard PIII 1Ghz. You could also upsample at the same time, although I'm not convinced its necessary. The problem is finding software that will do this on an input source rather than pre recorded audio.
     
  8. rob_w

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  9. buns

    buns
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    Thanks to avs i have come across QSC dsp products which seem to be dsp boxes but very much computer controlled...... somewhat more expensive than a bfd, but the dsp-4 product looks quite amazing!

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