SDA 2B: One speaker louder than the other

Airplay355

I'm using a pair of SDA2B (completely unmodified) with a Rotel RX-1050 receiver. One speaker is 2-3DB louder than the other. I've swapped the left and right to confirm the right speaker is the louder one so it shouldn't be the source (a Macbook) or anything on the receiver. I confirmed the difference with a pink noise test tone and DB level app. Not the most scientific of ways but good enough to confirm that I'm not a total nut with one blown out ear.

What would cause this? I don't ever remember them sounding like this before. I don't think it's room acoustics as they're in a very square bedroom.

TennMan

Could be a bad mid-woofer. You can test by momentarily connecting a 1.5 volt battery to the speaker terminals and watch to see if they move.

boston1450

Just a thought. Did you try clean the contact where your speaker cables/wires hook into your receiver. Also keep in mind 30+ year old speakers may need refresh on crossover parts. Hope u find issue-feel your pain

BlueFox

Is the setup behind both speakers the same, or different? For example, is one speaker close to a corner, and the other near a hallway.

boston1450

Deleted

Airplay355

Setup behind both speakers is completely identical. I thought first maybe it was because one wall has a window and that speaker was louder. After the speaker swap, that windowless side is louder.

Would it have to be the SDA driver that's bad? Both drivers seem like they're making sound just fine without any obvious crackling or anything and move freely when I push in the PR.

I haven't tried cleaning anything receiver side but figured since the quietness is following the left speaker and not the left side the receiver/source were fine. Am I thinking about that wrong? If the left speaker is swapped to the right, then the right side isn't as loud. If I swap them back, the left side isn't loud.

Could I check out the crossover and see if anything is damaged by removing the PR? Do crossover bits slowly go bad? I was expecting something to go all at once and I'd lose the tweeter completely or something like that.

F1nut

The electrolytic caps in your speakers are at least 30 years old, way past their lifespan. So, logic dictates that is likely the problem. Swap crossovers and if the issue follows it's time to upgrade the components.

Airplay355

I had hoped that wasn't the issue since everything seemed to work fine (until now) even though I knew the components are old. Thanks for the XO swap idea. I'll try that and see how it goes.

BlueFox

Everything wears out over time. Especially mechanical/electronic gear.

polrbehr

Look at the bright side, if you liked them as they were, they are only going to get better with any mods you do . It's not even worth considering NOT doing.

Airplay355

Trying to take the XO out of the left speaker. It seems like there's a bolt/screw holding it in place. I've tried loosening the screw and it just spins. I've tried spinning the XO while holding the screw and it just spins.

Am I doing something stupid?

F1nut

The glue holding the nut has failed. You'll have to remove the crossover board from the 4 standoffs, then use pliers or the like to hold the nut while unscrewing the bolt. Once you have everything apart resecure the nut with epoxy and wait a day before reassembly.

jbail2011

Could this be a non common ground amp issue?

audioluvr

Doubtful. If all your drivers and tweeters are working and speaker cables are not out of phase and everything else has been eliminated I'd follow @F1's advice and refresh the crossovers.