Thursday, June 29, 2006

Using DSP Quattro

My audio production application is DSP Quattro. I chose this over Sound Studio, which is pretty nice, because it seemed just a little bit more capable and flexible, and seemed like it would help me edit a bit better. I have to admit I was also taken in by the "scrubber" that lets me play audio backwards and forwards or fast and slow; it is a little bit like using a jog/shuttle wheel on a traditional video editing deck.

DSP Quattro is giving me a few pains, though. I need to get in touch with the makers and try to determine which of these are bugs and which are features I don't understand.

- Buffer sizes for my audio devices are not saved and loaded with the project. That means I have to set them up again every time I run the application and open up my project. Yeech.

- Sometimes effects won't respond to the "edit" button by opening their windows. Sometimes effects editing windows get dimmed and clicking on them won't fix this. There seems to be some problem with the state handling for these windows. Re-selecting the effect and then re-loading the preset you want to apply seems to fix the problem.

- The "Save Project" command seems to lose track of the fact that you are already working with a saved project, and wants to treat it like saving a new file. But only sometimes.

- This is a feature request: a list of recently active project and audio files would be very helpful. Often you're closing a file to overwrite it, then re-loading it; this would save some tedium.

- After you apply the master effects to a file, and save the results in a new file (or the already-open file), DSP Quattro turns on the master effects, which means that if you try to listen to the results of your processing, without turning that bypass back on for the whole Master effects strip, you will hear the effected file run through your live effect chain _again_. The result is often frighteningly loud and full of clipping, so this is not something you want to hear unexpectedly in your headphones!

- While you're applying master effects to a file (not in real time), the meter levels that you see flickering by occasionally are way too high and appear to indicate that you're seeing the effects applied twice. If they can't display something meaningful they should be turned off when running the effect chain at faster-than-real-time.

- Some plug-ins don't seem to allow me to properly control their values (for example, the Peak Limiter). I'm not sure if this is a problem with the host application or the plug-in.

- This last one may be something I don't fully understand. I've defined my master effects, and I've tweaked and tweaked them, by playing a source file and listening to the results. Then I go ahead and use the menu command to apply the master effects to the file, and save the results in a new file. (In other words, I don't run the effects in real-time, but as fast as the computer can run them). When I listen to the resulting, it sounds _different_ than it did running on the original file in real-time. I can get the result I want by using a master recorder and saving the results to the file, but this runs in real time, so it is a bit awkward. The difference is fairly dramatic -- the file that was processed faster is 5 dB higher in RMS, and the expander sounds all wrong (the beginnings of words are lost). What is wrong? Is the compressor not capable of adjusting its time-based values to correspond the actual number of samples it is processing when running faster than real time? I hope this is not the case -- I will be generating hours and hours of audio, and I don't want my post-processing to take as long as recording the audio did!

If you're an expert on DSP Quattro, I'd love to hear from you. Otherwise I'll be hunting for some other forum where I can get some assistance with these issues.

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