# Delay when processing FIR filters?



## Theeagle (May 16, 2008)

Hi Guys (and girls?)
The last couple of weeks I have been messing around with different kind of software for digital room correction/EQ. After quite a few measurings etc. I've got a descent FIR filter I would like to use. So far I have been using it with foobar and convolver, and it works just perfect :yay2:

My problem is, that I would like to use the FIR-filter with a VST-host, by doing so I should be able to run all sounds through the FIR filter. Unfortunately I'm experiencing quite a high delay when using convolver with a VST-host

So far my configuration is as following:
EMU 0404 soundcard -> all sound is being sent to ASIO in
Console (VST-host) -> picks up the ASIO-in signal 
Convolver - processes the FIR filter (131072 taps stereo filter in 44100 hz)
Console -> forward the sound to the ouput

From this link I found the following information concerning the delay associated with the use of FIR-filters:
(links removed due to restrictions)
_given a FIR filter which has N taps, the delay is: (N - 1) / (2 * Fs), where Fs is the sampling frequency_

If this information is correct, the 1.5 s delay is just a result of my pretty huge FIR filter. I just wonder, cause in foobar with convolver I haven't noticed this delay at all, and I felt pretty sure that it should be possible to process a FIR filter in (near)real-time.. But I might be wrong?

Anyone who can confirm if a fir filter can be processed in real-time or not? And perhaps know a solution:daydream:

Thanks a lot!

(I hope I have placed the topic in the right category)


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## brucek (Apr 11, 2006)

> I hope I have placed the topic in the right category


There really isn't a category for this question, but I would suggest re-asking the same question in the Convolver thread. You may get better play there. 

brucek


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## Theeagle (May 16, 2008)

Thanks a lot Brucek 
I have made a post in the convolver thread and hope that someone is able to help me out.

:T


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