Reading, filtering and playing large WAV files

Hi!
I want to build an application that reads LARGE wavefiles, filters them and plays them via the soundcard.
I tried to build something with the standard blocks available in Labview 7.0, but I keep running out of memory. The files I want to filter and play are simply too large The filesize is typ. 650Mb = 1 hour of stereo CD quality audio. The files I am using just won't play even on a WIN XP machine with 1Gb of memory.
Next step was to build a function that loads the WAV files in blocks of ~16kB. This works fine, but now the filtering does not work anymore; after each block, the 'FIR Filter' block seems to reset its states. The result is a very bad repeating artifact in the sound. The repetition-rate is related to the buffer size.
Does anyone have experience with this type of application? Help and examples are -very- welcome (as I am new to Labview... .
Many thanks,
Dr.dB

I have created a VI that will do the continuous FIR filtering you need. I assume you want to filter a 'stereo' signal so the VI takes an array of waveforms as input. In this version the FIR filter coefficients (kernel) is common to all channels. If this is not what you need you can correct the VI accordingly.
The control 'algorithm' specifies whether the FIR convolution is internally performed in the time or frequency domain. Changing the 'algorithm' does not affect your result but affects your performances. Select time domain (direct) if your kernel size (number of FIR coefficients) is, say less than 100, otherwise select 'frequency domain'.
Try the attached example and let me know if you have any problems.
Attachments:
continuous FIR filtering on multiple channels.llb ‏79 KB

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