Hello,
I have a pair of NAD 802 speakers and although I like the sound of them I think that one of em has a tweeter problem. I (think) I can hear somewhat of a scratchy sound sometimes. It's not permanent but at certain frequencies it makes me wonder if the tweeter might be either damaged or misaligned or something else which makes this scratchy thing at "mid frequencies". Are there ways to isolate this problem to be sure its even there and not just in my head? And even more important...are there solutions I can try to fix this? If not, is it possible to swap tweeters with other speakers if the parameters are identical or is there more to it than the obvious like size, impedance, power rating etc?
I'm going to exchange left with right speaker now and see if its still there or if it is indeed the speaker but thats all I can think of in order to figure things out.
What I noticed is that both tweeters seem to be slightly cracked around the screw holes and I already aplied a bit of glue to the craked parts but could this even be a source for scratchyness or could it even be a problem with the crossover capacitors ? I dont remember if I recapped them, will have to open them and have a look inside...
As you have probably noticed I'm a bit clueless when it comes to speaker healthcare 🙁
Thanks for any advise and have a great weekend!
I have a pair of NAD 802 speakers and although I like the sound of them I think that one of em has a tweeter problem. I (think) I can hear somewhat of a scratchy sound sometimes. It's not permanent but at certain frequencies it makes me wonder if the tweeter might be either damaged or misaligned or something else which makes this scratchy thing at "mid frequencies". Are there ways to isolate this problem to be sure its even there and not just in my head? And even more important...are there solutions I can try to fix this? If not, is it possible to swap tweeters with other speakers if the parameters are identical or is there more to it than the obvious like size, impedance, power rating etc?
I'm going to exchange left with right speaker now and see if its still there or if it is indeed the speaker but thats all I can think of in order to figure things out.
What I noticed is that both tweeters seem to be slightly cracked around the screw holes and I already aplied a bit of glue to the craked parts but could this even be a source for scratchyness or could it even be a problem with the crossover capacitors ? I dont remember if I recapped them, will have to open them and have a look inside...
As you have probably noticed I'm a bit clueless when it comes to speaker healthcare 🙁
Thanks for any advise and have a great weekend!
Those tweeters, I just can’t remember where, but I’ve seen them before. If you dismount them, could you post the type?
Scratching tweeters mostly have faulty or misaligned coils. The latter doesn’t happen just like that, only by heavy shocks. But even the crossover, the connections or the amp could be faulty.
Scratching tweeters mostly have faulty or misaligned coils. The latter doesn’t happen just like that, only by heavy shocks. But even the crossover, the connections or the amp could be faulty.
Only way to be sure is sweeping the HF driver with a sine wave to detect VC rubbing. This is usually very audible at lower midrange frequencies. Female vocals work well for detecting this too. Could also be a leaky or bad series cap in the crossover.
Here's a sinewave generator I like:
Audio Tools - from David Taylor, Edinburgh
Sweepgen. Aside loose or corroded connections already mentioned, old tweeters can have dried up ferrofluid in the magnet gap, which clogs the voicecoil. It also centres the voicecoil to some extent.
Fresh brown ferrofluid obtainable at Blue Aran near Southampton, UK and some Dutch suppliers.
Audio Tools - from David Taylor, Edinburgh
Sweepgen. Aside loose or corroded connections already mentioned, old tweeters can have dried up ferrofluid in the magnet gap, which clogs the voicecoil. It also centres the voicecoil to some extent.
Fresh brown ferrofluid obtainable at Blue Aran near Southampton, UK and some Dutch suppliers.
Hi, thanks for the answers and suggestions so far. How does sweeping work? So far I have taken one of the speakers apart and I dont think the tweeter works with ferrofluid as there is no residue whatsoever and having played around with ff I know how hard/impossible it is to remove its stains. My plan is to take the other one apart as well and see if the caps measure the same. The voicecoil looks fine to me. If you have suggestions what else I could do to evaluate (besides sweeping, first I have to find out how this works...umm...and also reassemble my frequency generator.)?
here's two pictures of the parts...this is the non scratchy one though...dont ask me why I took this one apart first...ok on my laptop the upload links work and here they dont...sorry...thats....hahahaha.....science 🙂
here's two pictures of the parts...this is the non scratchy one though...dont ask me why I took this one apart first...ok on my laptop the upload links work and here they dont...sorry...thats....hahahaha.....science 🙂
Try sweeping and see. Your ideas are as good as anybody's!
Far more likely you have a bad connection somewhere. A doubtful solder joint on the crossover, which can be reflowed with a soldering iron, or a corroded crimp wire connection. Visual inspection needed. Swapping amp channels is a plan too. Amps often get scratchy with age. Aerosol Switch cleaner can help.
Far more likely you have a bad connection somewhere. A doubtful solder joint on the crossover, which can be reflowed with a soldering iron, or a corroded crimp wire connection. Visual inspection needed. Swapping amp channels is a plan too. Amps often get scratchy with age. Aerosol Switch cleaner can help.
I tried swapping channels, its not the amp...not a vintage amp btw, it's a modern digital amp.
I'll see if I can locate the fault and report back...I have no idea how to properly center a misaligned tweeter for instance...so I'll ask more questions as soon as I know who the culprit is. thank you so far 🙂
I'll see if I can locate the fault and report back...I have no idea how to properly center a misaligned tweeter for instance...so I'll ask more questions as soon as I know who the culprit is. thank you so far 🙂