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Simulating crossover filters with VituixCAD and EQ APO

edited January 2022 in DIY

Ever wanted to listen to your passive filter design and make sure you haven't make any obvious errors before purchasing components and spending the time assembling a crossover? Well now you can! The attached instruction is a simple step by step to export filter transfer functions from VituixCAD as impulse response, which can be loaded into EQ APO using "convolution with impulse response". Following this easy process, any filter transfer function that you can create with VituixCAD can be imported into EQ APO as a digital filter and heard instantaneously.

This information was recently provided by Kimmo over at DIYAudio, I've simply compiled it into a basic step by step instruction.

I'm not deaf, I'm just not listening.


  • Nice!

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  • There goes the last feature advantage of SoundEasy!

  • edited January 2022

    It’s pretty slick, I’ll have to make a small update to the document though, just use the “copy channels” in APO EQ to copy the left and right audio to the other channels used on the sound card for the multichannel active system. Otherwise you may set up the midrange on the rear surround channel and have no audio there for playback.

    I would think that you can use a video card with hdmi audio capabilities and a HT receiver for this purpose as well.

    I'm not deaf, I'm just not listening.
  • @Ed_Perkins said:
    There goes the last feature advantage of SoundEasy!

    Yeah, unfortunate as it is, this is actually a LOT more convenient than the digital filter feature in SE. SE would require you to feed audio to the audio device input, basically turning your PC into a DSP. It is quite a "clunky" configuration in my opinion, most people will want to just play some audio files on their PC or use a streaming service etc which isn't really available with SE.

    This procedure is geared towards simulation of passive filter transfer functions, but with EQ APO and VituixCAD you can essentially turn any old PC into a audio streamer with fully active integrated DSP, any filter that can be designed with VituixCAD can be exported to an impulse response for digital processing with EQ APO. It requires surprisingly little CPU power so even the most basic PC like a little NUC or some fanless mini PC could be used.

    I'm not deaf, I'm just not listening.
  • I just put this on my "to do" list. If this works, I'll soon be able to develop accurate spinorama models and then actually listen to them before ordering parts! Thanks much! =)

  • Update document in first post to include implementation of channel copy, and some other minor clarification.

    I'm not deaf, I'm just not listening.
  • This reminds me - I have a license for LSPCad floating around, it had this feature. Not a very powerful measurement software, though.

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  • Yes it does. Actually there are plenty of options for IR convolution, it is commonly used to reproduce reverb effects, for example if you record the impulse response of a cathedral, you can recreate the reverb of the cathedral applied to any audio.

    I'm not deaf, I'm just not listening.
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