Hmmm....left SDA 1C highs lower than right..

avguytx

...and I've done the typical things to diagnose to find out if it's electronics related or speaker related. So far I've swapped all the inputs L/R's at the preamp on various sources and swapped the left and right speaker connections at the amp. Nope...stays with the left channel. I also took off the PR and shorted a lead across the thermal tweeter protection and that made no difference. And, for the finale`, I swapped the speaker outputs behind the amplifier. Damn....still stays with the left.

I did the crossover swap awhile back with great results and no problems. Maybe it's always been this way and I've just now become more "tuned" into them. Not sure. Both speakers play the same loudness level...it's like it's about 2 to 3db quieter from about 8kHz (maybe lower) on up on the left versus the right. I also played them with and without the interconnect cable just for the hell of it. I've played various kinds of music, listened to the radio, LP's etc. Same. Man, I do NOT feel like going back into those crossovers to check everything out. I triple checked everything before putting the crossovers back in and when working on them, only did one part at a time. It was a no brainer!

Maybe it's just me...maybe it's been this way all along...maybe it's one of those days. Sheesh...

avguytx

Darn...no ideas so far? I was hoping I missed something obvious! So far, I've just turned the tone controls "on" on the C-1 preamp and bumped up the treble at the 8kHz setting. Between 1 and 2 o'clock about evens it out I guess. I'm deliberating on ordering all new caps and resistors for the left channel because I know this will drive me nuts having to band-aid it. Maybe I should stick the CT-17 preamp back in there for awhile and see what happens. At least that would alleviate one more thing. Sigh....

Ron Temple

I feel for you...for the last 2 months I've experienced similar issues with my right side. Swapped tweeters, amps, ICs, pre-pros. I was sure it was the TFM35, then a 6510 driver or maybe the crossover...it seems to be the driver, luckily, Steve had a spare. Played with the Carver over the weekend and now that seems to be AOK. Plugged it back in last night driving the CRS+s. Works like a charm...so no trip to Rita .

Gremlins...I started to suspect it was my hearing on the right side...very frustrating.

Hope you get it cured before I did.

engtaz

I was installing mono amps into a friends system last night. He has SDA SRS2's. The right speaker was at a lower volume then the left speaker. Swapped amps,rca's and swapped speaker wires at the amp. No Luck. then I replace the speaker wire going to the amp and right speaker and then everything work perfectly. I have never seen that before. Just info. hope it helps someone.

avguytx

Maybe it's time to just go ahead and order the (4) RD0-194 tweeters and be done with it. Part of me is afraid I'll miss that peak at 14kHz or so because my hearing isn't what it used to be and then I'll have $200 in tweeters that I don't like! Then again, maybe I'll like them once broken in. There's always a treble control (or 2) on the preamp that can be turned up.

I have 16ga running to the SDA's right now and I think I'm going to order some 10 or 12ga from one of the vendors I rep just so I can have the larger wire going to them. I'll also use some of it on the new SDA interconnect to get rid of that small wire between them, too.

Thanks for the input!

heiney9

avguytx wrote: »

Maybe it's time to just go ahead and order the (4) RD0-194 tweeters and be done with it. Part of me is afraid I'll miss that peak at 14kHz or so because my hearing isn't what it used to be and then I'll have $200 in tweeters that I don't like! Then again, maybe I'll like them once broken in. There's always a treble control (or 2) on the preamp that can be turned up.

I have 16ga running to the SDA's right now and I think I'm going to order some 10 or 12ga from one of the vendors I rep just so I can have the larger wire going to them. I'll also use some of it on the new SDA interconnect to get rid of that small wire between them, too.

Thanks for the input!

I don't think you'll miss the peak. You still get all the detail, volume and crispness but without that grit and annoying peak resonance especially as the volume increases. If after break in you don't like them you can flip them here very easily.

H9

Ricardo

Why not swapping the crossovers? That will tell you if it's some of the components. I doubt it though, if you recently upgraded them.

I would by the new tweeters anyway.

ben62670

Swap the tweeters you have now. If the sound is bad from the XO then the likely culprit is the poly switch. Also while the tweets are out check them with a MM for ohms, and see how they match up.

avguytx

Ben...I shorted a lead across the polyswitch to "take it out of the loop". Would that not be a way of bypassing it for testing? It didn't seem to make a difference when I was sitting right by them and connecting/disconnecting the lead. I could hear no difference in the sound. That was one of the main things I thought would have caused the problem since it's only the upper response that's down. Everything else is fine.

danger boy

i just recently upgraded the crossover's in my monitor 7 speakers.. now one of the speakers is lower in volume than the other. it's weird.. so what people in here have been telling me is that one of the drivers. either the tweeter or mid driver could be going out. so I will replace one driver at a time and see what the results are.

has one of your tweeters gone bad?

avguytx

No, all 4 tweeters "work" and the left channel does play. It's just they don't have the same upper end response and the other side. I've still got to dig a little farther into it just so I know what it is exactly or it will drive me nuts! I'm going to put a meter on them and see what they read in relation to each other. I'm sitting here at my desk between them and the difference is noticeable. I think I'll grab another pair of speakers and put on top of these and see what happens when a completely different pair is hooked up.

danger boy

ok sounds like a good plan. so they just developed this problem?

My SRS's when I had them. would sometimes exhibit the same thing. But not a huge difference. I never could figure out what the probem was..

how about if you disconnect the SDA cable, does it still have the same problem?

Ron Temple

My troubles might be similar. I thought it was the tweets at first too. All the drivers and tweets were working on the right, but the top end dynamics were missing. The SPL meter said I was down 4-6dbs and no matter how I compensated, the top didn't sound right. Check the drivers too.

avguytx

Well, trying another pair of speakers (Dynaco A-25's) showed me that it's the speakers. I played a familiar song on both and the left Dynaco definitely wasn't lacking in the upper end response. I know that the speakers "voicing" is a little different but it did what I needed it to do for the testing. I guess it's not a really huge difference and maybe I'm making more of it than I should (that goes without saying). But, I still hear the difference no matter where the seating position.

Yeah, I tried it without the SDA cable, too, and it makes no difference. Wasn't it the 1C's (and others) where the SDA effect was more on the dimensional speakers and didn't affect the tweeters? I know when the cable is unplugged, there is still sound from both tweeters on each channel. Maybe I'm wrong on that. Oh well...I'll look into the guts of them tonight time permitting and might even swap the crossover section that controls the tweeter section. It's a little tougher on mine because the crossover is not on one board...it's on two. Kind of the transitional version of the 1C Ken said.

avguytx

Ron Temple wrote: »

My troubles might be similar. I thought it was the tweets at first too. All the drivers and tweets were working on the right, but the top end dynamics were missing. The SPL meter said I was down 4-6dbs and no matter how I compensated, the top didn't sound right. Check the drivers too.

Ron, which drivers are you referring to? All of them? Both sides play at the same level overall but it's just the upper response that's lacking....the ambience I guess you could say.

Edit: Metered all of the tweeters On the left side, both read 7.0 ohms and on the right channel they are 7.0 and 7.2 ohm each

Ron Temple

avguytx wrote: »

Ron, which drivers are you referring to? All of them? Both sides play at the same level overall but it's just the upper response that's lacking....the ambience I guess you could say.

Edit: Metered all of the tweeters On the left side, both read 7.0 ohms and on the right channel they are 7.0 and 7.2 ohm each

A 6510 dimensional was the culprit for me...Steve measured it and told me it was in spec, but there was a bit of scratchiness. The new driver made all the difference. I'm not technically gifted so I go by ear. I'm just sharing that I thought it is a tweet or the amp and it ended up being an SDA driver. I hope it's as simple as that for you.

danger boy

ok. i'm a big old newbie when it comes to measuring the Ohms of speakers.. I know you need a multimeter... but please give me a brief run down on how it's done.

are the speakers powered up when you do this? what else?

thanks. sorry for the thread derail.

avguytx

No, you don't want them powered up as it will give you reading thru the entire chain. You measure each speaker independently and unhooked from the rest of them. If you measure the terminals on the back of the cabinet itself, it gives you a reading with all speakers and crossovers combined.

Here's a picture of a speaker with the DMM attached to it. Yeah, I know...it's an old Realistic woofer. It's all I had handy. Maybe that will give you the general idea. Remember...this is only DC resistance of the speaker and any movement of air, noises, etc that can move the cone while doing it will cause it to fluctuate. Hook a meter onto the speaker and push in on the cone and see what happens. It will fly all over the place as the V/C is moving in the gap. Just like it fluctuates when it's actually playing which shows various loads to an amp at any given time.

Ron....one of the mid woofers was causing the upper end to be that much down? Even with the SDA cable unplugged, it still does it on mine. I thought that might have taken those drivers out of the loop. I thought I read where the later series of the dimensional effect was only in the midrange area and not as much the upper end. Or am I thinking of the Sonic Holography that Carver uses (which I never engage on these speakers).