Colloms wrote that Doppler distortion only becomes significant for excursions above 3 mm peak in fullrange drivers (i.e. that it is a non-issue for all other cases).
He also wrote that below that excursion value IMD would be dominant and that the effect of Doppler distortion would be almost similar to IMD anyway.
Regards
Charles
He also wrote that below that excursion value IMD would be dominant and that the effect of Doppler distortion would be almost similar to IMD anyway.
Regards
Charles
Charles,
Although I never took measurements Colloms seems to be close to the mark. I tried calculating with a formula given by Langford-Smith (Radio Designer's Handbook, p. 869) but there is something wrong with that formula (gives too high a value). Below that L.-S. gives examples for a 30cm driver at a reasonable input (amplitude not given), of 0,65% distortion for 1 KHz and 6,4% for 10 KHz. And this is intermodulation distortion; rather lower than perhaps other driver distortions.
But I would expect that to be quite higher for smaller drivers. You possibly have more experience than myself, but I did notice small woofers going at an amplitude of at least 3mm! But as you said, by that time one would certainly use a multiple driver set-up.
Still I am going to try get a proper formula; one does see highly acclaimed two-way systems crossing over at over 1 KHz, with small woofers. Somewhat off-topic, but perhaps others can enlighten us?
Regards
Although I never took measurements Colloms seems to be close to the mark. I tried calculating with a formula given by Langford-Smith (Radio Designer's Handbook, p. 869) but there is something wrong with that formula (gives too high a value). Below that L.-S. gives examples for a 30cm driver at a reasonable input (amplitude not given), of 0,65% distortion for 1 KHz and 6,4% for 10 KHz. And this is intermodulation distortion; rather lower than perhaps other driver distortions.
But I would expect that to be quite higher for smaller drivers. You possibly have more experience than myself, but I did notice small woofers going at an amplitude of at least 3mm! But as you said, by that time one would certainly use a multiple driver set-up.
Still I am going to try get a proper formula; one does see highly acclaimed two-way systems crossing over at over 1 KHz, with small woofers. Somewhat off-topic, but perhaps others can enlighten us?
Regards
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