diyAudio

diyAudio (https://www.diyaudio.com/forums/index.php)
-   Subwoofers (https://www.diyaudio.com/forums/subwoofers/)
-   -   subs in free air for testing (https://www.diyaudio.com/forums/subwoofers/318768-subs-free-air-testing.html)

robinlawrie 12th February 2018 09:42 PM

subs in free air for testing
 
im currently in the first testing phase of my 6 channel 3255evm amp.

ive got a minidsp 2x4hd splitting the signal and two btl channels for subwoofers.

speaker cases are currently being cnc cut.

im quite worried as when i hook it all up for testing, the subwoofers sound distorted and awful, even at low volumes and excursions.

according to the minidsp plugin there is no clipping going on anywhere, ive tried analog and usb inputs, same story.

strangely if i run a tone generator, pure tones sound clean. but its a different story with music.

the other channels of the amp (running to old car speakers without cases for testing) with highpass at 100 hz, sound fine.

chris661 13th February 2018 07:25 AM

Looks like it's time for some troubleshooting, then.

Drivers:
- Do the cones move smoothly when you push them?
- Is the DC resistance somewhere sensible? You want 2.9-3.5ohm DC for a 4ohm woofer, or 5-7ohm for an 8ohm woofer.

What happens when you take the MiniDSP out of the signal path?
What about using a different amplifier?

Swap things out, one at a time, until you find the culprit.

Chris

RobWells 13th February 2018 09:47 AM

If the sub driver is not in a box then it won't take much to drive it past xmax ? Maybe try it in a box.

DiscoJones 13th February 2018 02:40 PM

Quote:

Originally Posted by RobWells (https://www.diyaudio.com/forums/subwoofers/318768-subs-free-air-testing-post5340001.html#post5340001)
If the sub driver is not in a box then it won't take much to drive it past xmax ? Maybe try it in a box.

I agree. Some subs produce a lot of mechanical noise that you won't hear once mounted in an enclosure. Don't waste your time troubleshooting a problem that may not be.

Dan

robinlawrie 13th February 2018 02:46 PM

Quote:

Originally Posted by DiscoJones (https://www.diyaudio.com/forums/subwoofers/318768-subs-free-air-testing-post5340246.html#post5340246)
I agree. Some subs produce a lot of mechanical noise that you won't hear once mounted in an enclosure. Don't waste your time troubleshooting a problem that may not be.

Dan


yes thats what im worried im doing!

however a) its definitely not xmax, i can hear the distortion clearly when the cone is only moving a mm or two (13mm xmax drivers)

b) wood is being cut for drivers now, but wont be here for a few weeks... i guess i could rough up a box from plywood...

c) i want to finish constructing the amp, and i cant do the final mounting of components until im sure its working properly..

anyway im going to do some initial testing of amp tonight.. ill report back.


All times are GMT. The time now is 07:31 AM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 17.65%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio

Wiki