FIR filter tool

J.Luszczek

What software other than the heavyweights like Filtershop or Matlab can be used to generate FIR coefficients for London DSP?
Let's say I'm on site tuning a system and I have a challenging acoustic environment that could use the FIR filter. Using the tools I have I can generate the impulse response and the inverted impulse response as a wav file.
Is there a software utility I can run that will generate London compatible coefficients list from the impulse response? If not, would the developers please consider releasing something or adding it to the tools inside London or Audio Architect? I bet the FIR block would get much more use.

bidland

You could import your .wav impulse in the brilliant freeware measurement software HolmImpulse and export it again as a .txt file, rename to .dat and load it into the FIR block in London Architect.

Acourate is a very powerful tool for generating FIR filters.
You can measure the response, define a target curve and make an inverse filter very easily with the macro functions.

J.Luszczek

I looked at Acourate. It does look good.
I used Holm Impulse briefly at home, but I found that I have better tools for measurements already so I didn't pursue it further.
Can it export txt files of arbitrary length? I found that loading a long FIR filter into London processor uses way too much DSP horsepower- on the order of 50% per 4096 tap long filter.
That's why I would love to optimize it to be as short as possible.

bidland

Yes, HolmImpulse lets you select the to- and from- sample number in the export function. I'm not sure if it's a good idea to truncate a FIR filter this way, though.

Acourate lets you apply windowing functions and keep the impulse peak in center when reducing filter length.