help measurin imp in soundeasy

[ravslanka]

hi

i own soundeasy 14 given to me by a friend
i have jigglimg with this software for about a week .iam doing an
impedance measurement for a 5' inchi woofer.i have done everything
according to help manual by music and design.iam not getting the proper graph of spl/phase vs frequency.the curve is not rising at higher frequency.because of which it is giving error

http://i43.tinypic.com/f447px.jpg

here are the screen shot step by step

http://i40.tinypic.com/153oe0w.jpg

http://i43.tinypic.com/2r7vs69.jpg

http://i43.tinypic.com/bhlfzd.jpg

using 10 ohm series resistor with driver.connecting my sound card with a 100k passive control in between the amp and sound card.
amp is based on tda2030 .using the probes with 47/22k resistors for line in.

i have checked with these setting of preferences too
here is the screen shot of my preferences

http://i39.tinypic.com/24o2cs2.jpg
iam pulling my hair


ravs

pleasehelp

[ultrachrome]

I've found that hair pulling is normal with SoundEasy.

I noticed in your first pic that you have Re expressed as 7-3 instead of 7.3. Not sure if that would have any effect.

The main difference I see is your impulse response looks different than mine. Mine swings up and down equally while yours only seems to go down.

I'd double check your connections. I'd also be tempted to try it without the attenuator, setting your SoundEasy output level appropriately.


Edit: PREFERENCES!!!!
I think I just found your problem. In preferences you have your freq range set to only 5,000Hz. Bump this up past 20k.

[slogan2112]

Try measuring a resistor in place of the driver and see if you get a constant impedance vs frequency.

[ravslanka]

hi ultrachrome

i change the frequency from 5000 to 20000 and then to 50000 from non linear screen-frequency range in preferences but that didnt made any difference the impedance graph is still the same
the imp curve shoud similar to this one

http://i41.tinypic.com/11rtdeo.jpg

so what next now

thanks

ravs

[ravslanka]

Originally posted by slogan2112
Try measuring a resistor in place of the driver and see if you get a constant impedance vs frequency.

hi slogan2112

as you said to replace the driver with a resistor here it is with 15 ohm resistor

http://i39.tinypic.com/xngg0g.jpg

[ultrachrome]

Originally posted by ravslanka
hi ultrachrome

i change the frequency from 5000 to 20000 and then to 50000 from non linear screen-frequency range in preferences but that didnt made any difference the impedance graph is still the same
the imp curve shoud similar to this one

http://i41.tinypic.com/11rtdeo.jpg

so what next now

thanks

ravs

Yes, in retrospect, I see that my suggestion was in error.

Your resistor trace looks good.

After your resistor impedance trace, did you then again try measuring your woofer?

[mcmahon48]

and on the Re did you also dmm it and try some different values around the Re these software oriented are very touchy
also make shure that you have a cabling diagram you may want to have your friend walk you through it

[ravslanka]

Originally posted by ultrachrome


Yes, in retrospect, I see that my suggestion was in error.

Your resistor trace looks good.

After your resistor impedance trace, did you then again try measuring your woofer?

hi ultrchrome

yes i did .first i calibrated with a 15 ohm resistor in place of a driver with 10 in series to the output of the amplifier.then replaced the 15r
with the driver.no difference.

screen
http://i42.tinypic.com/2dmhzdk.jpg

[ravslanka]

Originally posted by mcmahon48
and on the Re did you also dmm it and try some different values around the Re these software oriented are very touchy
also make shure that you have a cabling diagram you may want to have your friend walk you through it

hi mcmahom48

i have tried 3 different drivers with different re measured with dmm
5.3 ohm.3.6ohm,7.3ohm.here is cabling diagram.i have tried inveting data and reference channel in preferences.

ravs

[john k...]

Have you tried a loop test? That is, using one output from one channel of your sound card, connect it directly (no amp or preamp in the circuit) to the L and R sound card inputs using a Y connector. Then take an SPL measurement (not impedance). Lease the start of the window at zero. You should see flat response.

What I see in your measurements looks as if one channel of you sound card has rolled off high frequency response. You appear to be doing everything correctly.