October 29, 2004

transient perfect

The idea of transient perfect.

A musical signal (or any wave for that matter) is very complex, often consisting of many different frequences superimposed upon one another. The perfect example of this is a square wave. A true/ideal square wave is composed of all frequencies. Because of this, when frequencies are phase shifted due to physical or electrical characteristics, the superposition of waves of different frequencies becomes distorted. Hence, our square wave, when introduced to phase shifts is no longer a square wave. It may not even closely resemble a square wave. So the idea of a transient imperfect filter sounds like a horrid idea. The harmonics of our signal become jumbled and the signal can be changed quite dramatically. Keep in mind, we're still talking about the time domain here. Once we switch to the frequency domain, things may look slightly better. The frequency response of our filter may not look half bad. In fact, the frequency response might look quite good. Just look at a 2nd or 4th order Linkwitz-Riley filter connected to drivers with time-aligned acoustic centers. The frequency response of this system is nearly flat in the pass band. This tells us that our filter will pass our signal with a minimal amount of distortion to our signal in terms of frequency attenuation/amplification. But by looking in the frequency domain we lose sight of the transients of our signal. Sure the filter may pass frequencies without attenuating them, but it may delay them, which still changes the output of the filter with repsect to the inputted signal.

Posted by mrpibb at October 29, 2004 6:34 PM | TrackBack
Comments

i read the whole thing... expecting it might turn into some sort of dialect i understand. and i was wrong. but i'm sure if i got it, it would've been very interesting.

Posted by: hollimer at October 30, 2004 1:03 PM

Hmm, never thought about that, but now that I have it is a very interesting idea. I'm betting we could do tests for this, but we'd need some serious equipment, say much more serious than an oscilliscope.

Posted by: Dave at October 31, 2004 10:56 PM
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