Go Back   Home > Forums > Blogs > Rob's active 3way with transconductance chipamps build blog

My build blog for my active 3 ways.
Rate this Entry

3 way post #9 - tweeter distortion measurements

Posted 16th November 2009 at 02:50 AM by relder

Unlike the mid and woofer - the tweeter doesn't seem to show any gains under current drive.
Attached Thumbnails
Click image for larger version

Name:	SE-fountek-nearfield-distortion-VS.gif
Views:	822
Size:	32.6 KB
ID:	45   Click image for larger version

Name:	SE-fountek-nearfield-distortion-CS.gif
Views:	561
Size:	31.6 KB
ID:	46  
Posted in 3 Way
Views 1315 Comments 2
Total Comments 2


  1. Old Comment
    Iain McNeill's Avatar
    Hi Relder,
    Nice write up - I'm interested in your progress.
    Can you help me understand your distortion charts here? I'm wondering why there is so much ripple on the thick blue trace on top. That's the fundamental right? or is it the RMS level of everything?

    But the ripple, is that a windowing artifact? I would have expected the fundamental to be smoother (but with a few warts)

    The distortion curves are from an FFT, looking at RMS levels in the n*F1 bin?

    What was the stimulus? Swept sine or MLS?
    Posted 18th November 2009 at 02:44 AM by Iain McNeill Iain McNeill is offline
  2. Old Comment
    relder's Avatar
    Hi Iain,

    I presume the ripple is due to combing effects of nearfield measurements given the ribbon is a little (2") line source. It should disappear when I do 1 meter MLS measurements for the crossover.

    Upper most line is the fundamental. Gated far field MLS measurements will be much more accurate for that.

    As far as I know distortion measurements can only be done with swept sine, not MLS.

    I hope to do some MLS measurements in the next few days.

    Posted 18th November 2009 at 06:19 PM by relder relder is offline

New To Site? Need Help?
Copyright 1999-2017 diyAudio