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AE TD12x SEOS12 Build!!!! - Page 13

post #361 of 377
polarity on the tweeter inverted when it should not be
post #362 of 377
I'm also interested, since I'm really close to finishing a TD12X ported build with bwaslo's XO + upgraded caps (just like you, bhazard).
post #363 of 377
people are talking about it here, measure your speaker see if you have a dip

http://www.avsforum.com/t/1461425/seos-12-dna-360-eminence-delta-12lfa-curved-build/100_100#post_23599367
post #364 of 377
Quote:
Originally Posted by Sibuna View Post

people are talking about it here, measure your speaker see if you have a dip

http://www.avsforum.com/t/1461425/seos-12-dna-360-eminence-delta-12lfa-curved-build/100_100#post_23599367

Good catch. I'm lucky enough in that Trinnov has the capability to correct this, but a quick polarity swap is easy to try. My initial observations were the same about being "flat" pre trinnov.
post #365 of 377
Thanks, Sibuna! I would have never noticed that. I still have a few days before finishing, so I'll wait to see how it fleshes out.
post #366 of 377
Thread Starter 
Quote:
Originally Posted by bhazard View Post

What crossover issue might I ask, since I have the same one?

Quote:
Originally Posted by bhazard View Post

Good catch. I'm lucky enough in that Trinnov has the capability to correct this, but a quick polarity swap is easy to try. My initial observations were the same about being "flat" pre trinnov.

True that, however the fact that the tweeter is out of polarity is going to wreck your impulse response as well. So correction software like Trinnov or Audy will help the FR, but you are still going to have issues that just a simple polarity switch would help anyways. I definitely see a dip in my graphs so I plan on posting my findings here when I do have the results.
post #367 of 377
Quote:
Originally Posted by bhazard View Post

Quote:
Originally Posted by Sibuna View Post

people are talking about it here, measure your speaker see if you have a dip

http://www.avsforum.com/t/1461425/seos-12-dna-360-eminence-delta-12lfa-curved-build/100_100#post_23599367

Good catch. I'm lucky enough in that Trinnov has the capability to correct this, but a quick polarity swap is easy to try. My initial observations were the same about being "flat" pre trinnov.

Trinnov can't correct for the driver phase mismatch. The drivers will always be ~180degrees(I don't know the actual correct phase angle) out of phase it doesn't matter what signal you feed them.

Trinnov corrects for phase issues of arriving sound at the listener by adjusting the speaker output. In this case the speaker is essentially mute in the reverse null region and can't physically produce the sound.
post #368 of 377
Quote:
Originally Posted by NicksHitachi View Post

Trinnov can't correct for the driver phase mismatch. The drivers will always be ~180degrees(I don't know the actual correct phase angle) out of phase it doesn't matter what signal you feed them.

Trinnov corrects for phase issues of arriving sound at the listener by adjusting the speaker output. In this case the speaker is essentially mute in the reverse null region and can't physically produce the sound.

It explains a lot.

If you didn't find this out, I would have never known. The day can't end soon enough.
post #369 of 377
Thread Starter 
Haha, I hear that. do you have the ability to measure the difference? If not, hold off and let me get my rig out tonight and let you know what I find. For sure if mine is wrong, then yours is going to be too.
post #370 of 377
Quote:
Originally Posted by beastaudio View Post

Haha, I hear that. do you have the ability to measure the difference? If not, hold off and let me get my rig out tonight and let you know what I find. For sure if mine is wrong, then yours is going to be too.

I have a calibrated mic, ASIO4ALL, and REW. I just never learned how to properly take a measurement. I guess I'll take a crash course tonight while trying to measure.
post #371 of 377
Thread Starter 
well in this particular case you are wanting to do close mic measurements. get the speaker away from any walls if you can and mount the mic about dead center between the horn and the top of the woofer around 1m away. elevate the speaker off the floor as well. This should give you relatively accurate response measurements for this particular test. normal measuring you would leave the speakers in place and test from the MLP or other seating positions, but not for native speaker response. The reason being you want to take the room out of the equation so measuring up that close helps to accomlish that. If you want to get dead serious, then real groundplane measuring should be done outside. I don't have any where quiet enough to really pull that off unfortunately.
post #372 of 377
I don't even think I need measurements to make sure. There is an immediately noticeable improvement after the swap.

Voices always seemed a bit held back, and I always thought it was from running phantom center. Turns out it was the reverse polarity all along.
post #373 of 377
Thread Starter 
Well good deal then!! The lady hasn't been feeling too well tonight so I haven't been able to take the measurements. Hope to get on that soon, but friends coming into town tomorrow. Crappy weather will make it easy tho smile.gif
post #374 of 377
Quote:
Originally Posted by bhazard View Post

I don't even think I need measurements to make sure. There is an immediately noticeable improvement after the swap.

Voices always seemed a bit held back, and I always thought it was from running phantom center. Turns out it was the reverse polarity all along.

This might help explain why I thought I was hearing a noticeable improvement when I went active. Part of that could have been due to the reversed crossover.
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post #375 of 377
Thread Starter 
Perhaps!!! I mean a few dB's in that critical range definitely will play a major part in what you are hearing. I mean having a crossover point smack dab in the middle of such important area of the freq spectrum has always struck me as a bit odd, but I digress. I will hopefully get to try it myself sooner rather than later smile.gif
post #376 of 377

Yeah, I had a design with reverse polarity too, and I didn't understand the schematic was telling me to reverse polarity on the tweeter. Tuxedocivic helped me to measure 1m away and switch the leads to the tweeter and all was well.

post #377 of 377
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