Noise from SDA 1B's

crawdad

Please Help.

I have noise coming from my SDA 1B's. I originally purchased in 87 or so. I hate to admit, but have always heard this noise. I even heard when demoing, but the sales rep said it was the tweets and promptly had them changed and had me out the door with new speakers which still had the noise. Due to time, embarrassment etc. etc. never did get taken care of.

To get to the noise:

It seems to be a low frequency crackle or distortion which sounds almost like tearing. It seems to come primarily from the Dimensional Mid-drivers, but I may be wrong. I did the check of the SDA cable and found both speakers to be getting the appropriate signals. I am technical but have limited tools/test equipment. I physically inspected the mids and did not see a tear in the cone, voice coil, or foam edge. This sound can be picked up at rather low volumes. I have tried different sources, amps etc. Still the same result. I heard mention of some type of styrofoam on the radiators that can separate. Could this possibly be the culprit?

Any ideas appreciated.

nadams

Coudl be a rattle due to a loose crossover... could actually be any number or things. What equipment areyou driving them with?

Tour2ma

Both speakers are doing this?

And shutdown the parallel thread over in Troubleshooting, if you would. It may have been more appropriate, but this one's going now and it just gets confusing with two.

Suggest that you edit your first post in the other thread and install a link to this one here...

Welcome to the Club...

crawdad

Sorry,

Killed other thread!

The noise is from both.

Talked to Polk tech support yesterday and they suggested pulling drivers and hooking music directly to them to try to pin point. I only had time to do one speaker (both mids), but it seemed to check out OK. I did notice if I manually press on the driver on one side, that is, misaligning the core/coil I get the same noise. I get this with relatively little pressure. I know not the best practice, but I am getting desperate.

F1nut

If that's the same noise you get while playing music thru them it would suggest bad drivers.

RuSsMaN

You don't even have to press on the mid drivers, or remove them for that matter. Just press in (cycle) the passive radiator gently, you've got scratching, you need new drivers. It should be fairly obvious which ones are making the noise.

Cheers,
Russ

Tour2ma

crawdad wrote:

Sorry,
1. Killed other thread!
2. The noise is from both.
3. I did notice if I manually press on the driver on one side, that is, misaligning the core/coil I get the same noise. I get this with relatively little pressure. I know not the best practice, but I am getting desperate.

1. Thanks
2. Seems odd.... Could just be coincidence I guess.
3. Do as Russ suggests. You never ever want to do what you say you did. You're forcing the misalignment. Promise to never do this again.

I'd say to continue the checks Polk CS suggested, but also look at the soldered conections in your signal path, e.g., binding posts, cross-over, etc. Could be a bad/ loose solder connection. At least that's what the "crackling suggests to me...