BTW, I also purchased a large number of those Foster ribbons. What is the lowest frequency you would cross with a third order? have you tried loading it with a waveguide?
Wrong, onkyo go flat to 18kHz.
https://www.diyaudio.com/community/threads/ultra-cheap-mtm.345405/#post-5979057
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Found this old post from my former self:
https://www.diyaudio.com/community/threads/tweeter-resonant-frequency-missing.103407/
Concluded some tweeters are sufficiently damped (if voice coils not seized) that resonance does not appear.
https://www.diyaudio.com/community/threads/tweeter-resonant-frequency-missing.103407/
Concluded some tweeters are sufficiently damped (if voice coils not seized) that resonance does not appear.
Definitely a posibility. I measured few, they all look consistent. And sound good.
Anyway, i just got dats, so i am not familiar with all the nuances. I am here to learn.
Thanks.
You can also change the test level Go to generator mode (menu item) where you can increase / decrease sweep level (dBu). Max is 11.4 I think before clipping occurs:
I can't recall actual voltage and given any current limiting of USB, DATS doesn't accurately measure T/S in terms of matching "higher voltage" T/S factory measurements from the likes of SB Acoustics. Or it could be user error. This is an SB17NBAC35-4:
I can't recall actual voltage and given any current limiting of USB, DATS doesn't accurately measure T/S in terms of matching "higher voltage" T/S factory measurements from the likes of SB Acoustics. Or it could be user error. This is an SB17NBAC35-4:
Great info, thanks. I will experiment with test levels.
My understanding is that in order to get accurate T/S data, one must attach certain weight to the woofer or mid cone.
My next goal is to see if i can measure bassreflex tuning in small 2way bookshelf.
My understanding is that in order to get accurate T/S data, one must attach certain weight to the woofer or mid cone.
My next goal is to see if i can measure bassreflex tuning in small 2way bookshelf.
Later, verify impedance of all 3way and 4way speakers i built if it does not dip too low. Most of the time i make 8 or 16 ohm speakers, just to be classA amp friendly and low distortion load. Even classAB amps benefit from higher impedance load. Its a mistake to have low impedance dip i try to avoid. DATS should be able to verify my builds.
Measured my test bookshelf. Its 2way with Aurum Cantus AC130F1, plus ribbon tweeter. I optimized cap to ribbon, to have smooth transition in crossover point. But i never measured low fr extension. No unechoic room here. I used commercial parts express box of unknown volume, but it has bassreflex in the back. So i was curious where it tunes. Looks like 35Hz. It produces nice deep clean lows, but AC130 is no woofer. Wonderful midrange. Great for testing sound of amps and preamps. With sub, this would be great system.
Attachments
Remember to short the leads for calibration. This will deduct roughly 0.3ohms from the measurement allowing for dats test lead impedance for more accurate results. You'll see this value bottom right under T/s parameters
I've found the impedance sweep quite accurate abd very useful to see nuances such as port resonance standing wave or other reflection / noise issues
I've found the impedance sweep quite accurate abd very useful to see nuances such as port resonance standing wave or other reflection / noise issues
Yes added mass requires accurate weight which I applied. As you'll see I tried 3 of the different options to do Vas measurement and they all ended up similar values. Delta compliance was the only one not verified and that may be best
As you are using Windows - you can ALT-PrtScreen (copy the in focus window) or Msoft key - Shift - S - to "lasso" an area on the screen to grab then paste here. might find it easier / quicker than photo / phone upload
That was suggested, i know that. But that computer is not on the net. Would have to copy to usb...too much hassle.
I take pic with phone and post directly as i type.
Sorry, quality is not the best.
I take pic with phone and post directly as i type.
Sorry, quality is not the best.