• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

Low volume distortion - caps or voice coils?

robobxman

robobxman

Roll me away tonight...
I recently noticed distortion (like muffled static) from my Ohm Walsh 4s, clearly audible at low volumes - harder to hear at high volumes, but it's still there. I changed components to confirm it's the speakers, and it is. I also adjusted the switches in the back for lows and highs, but it had no effect.

Would old caps have this effect? I am dubious, but hopeful, as I can change those. As for the voice coils, if they are the culprit, I can have Ohm fix those.

Thoughts? thanks.
 
Register to hide this ad
robobxman said:
I recently noticed distortion (like muffled static) from my Ohm Walsh 4s, clearly audible at low volumes - harder to hear at high volumes, but it's still there. I changed components to confirm it's the speakers, and it is. I also adjusted the switches in the back for lows and highs, but it had no effect.

Would old caps have this effect? I am dubious, but hopeful, as I can change those. As for the voice coils, if they are the culprit, I can have Ohm fix those.

Thoughts? thanks.
Click to expand...

Is it happening in both speakers or just one ??
You said that you changed components but have you connected some other speaker to at least one of the channels ??
It would be highly unusual for both speakers to fail in the same way simultaneously ...

Could be the source, amp, wiring, or the wall power if it's occurring in both speakers simultaneously ...
 
If it’s just one speaker, lie it on its back and try gently pushing the woofer. If you feel rubbing it’s the VC. If not try playing a low frequency, maybe 60 Htz and see if you hear it.

as mentioned two speakers going around nearly the same time is like having two tires blow out at the same time. I suppose it could happen but it’s unlikely.

Not very familiar with OHM drivers but sometimes if you’re lucky the magnet is bolted or screwed onto the basket and not fixed, if this is the case you might be able to re-align the VC and magnet by loosening the screws and adjusting slightly.
 
as F1 nut said, if the surrounds are shot, and not holding the cone in alignment, then the voice coil may be rubbing, but it is likely ok. So the cone may be tilted down at its resting spot.
 
I'm not sure if the Walsh 4's have a surround that needs replacing. One of the line up, I think the 3's suffer surround deterioration. But I believe the 2's 4's & 5's use a doped cloth surround which should hold up pretty well over the years. The only way to really know would be to crack open the cans and check.

Short of calling Ohm and getting input from them. It may be something as simple as corrosion/dirt on the dip switches.
All of the switches on Ohm speakers are self cleaning. Working each one for each tweeter, mid bass, position etc several dozen times each may solve what you are hearing. I know you said you moved their position. But I am not exaggerating when I say move each switch several dozen + times.

If you have access it couldn't hurt to hit them with a little contact cleaner too. But only if you can access the rear of the switches without damaging the cabinets. If not working them rigorously may just do the trick.

Capacitors failing and increasing in ESR with age normally manifest as a rolled to very rolled off high end. And speakers or drivers in the speakers, depending on where the component lies in the signal path - may seem hard to get good SPL out of. As the resistance of the aging components continues to increase. Stranger things have happened, but your issue doesn't seem to be related to this.

Cheers
 
Last edited:
Sometimes the glue on dust caps can come slightly loose. Check them, a little super glue on the end of a toothpick can fix that
 
Thanks, guys. It's happening in both speakers and I changed everything upstream to ensure it wasn't that. And I'd love to inspect the drivers, but as you know, they are encased in that impenetrable black can.

@MetalDaze - my highs are just fine, certainly not rolled off in any noticeable way and I did cycle the switches about 7 or 8 times but can try again (thx).

Now ... as for the cause, I generally play these at lower volumes but have had a couple of scotch-induced loud listening sessions, and I wonder if that caused this. Because the distortion is subtle, and I don't play these every day, I may have missed it for a few weeks. And for a long time, I had bad speaker cables (the pins had bad connections), so I kept fussing with those. Honestly, I thought for sure it was something with my cables or components until I tested the 4s with my office system yesterday (and another pair with my main rig). The crazy thing is at even medium volumes these sound great, but I'm sure the distortion is being masked.
 
It is possible that with a long enough session of square waves, thanks to our friend alcohol, that you overheated the voice coils and the circuit may not be totally blown but they started to warp, or corrode through, causing them to only slightly rub on the magnet ring. That probably would be the most likely situation for the pair to have components go.

It might still be worth it to run a frequency sweep, just download a free fq generator app and run through a few octaves to see if the sound is associated with a specific fq. Keep trying! I thought I had lost a 55 year old Wharfedale midrange but managed to save it with patience, trial and error.
 
CJ Payne said:
It is possible that with a long enough session of square waves, thanks to our friend alcohol, that you overheated the voice coils and the circuit may not be totally blown but they started to warp, or corrode through, causing them to only slightly rub on the magnet ring. That probably would be the most likely situation for the pair to have components go.

It might still be worth it to run a frequency sweep, just download a free fq generator app and run through a few octaves to see if the sound is associated with a specific fq. Keep trying! I thought I had lost a 55 year old Wharfedale midrange but managed to save it with patience, trial and error.
Click to expand...

Thanks, CJ. Just took your advice. Now, I'm not a sound engineer but I ran various octaves. Sound is smooth above 65hz. From about 8hz to 65hz, I hear crackling/distortion.
 
robobxman said:
Thanks, CJ. Just took your advice. Now, I'm not a sound engineer but I ran various octaves. Sound is smooth above 65hz. From about 8hz to 65hz, I hear crackling/distortion.
Click to expand...

I kinda doubt that you're the first guy to get a little over enthusiastic with a pair of speakers ...

And not the last..
 
And you say it happens at low volume as well as high volume? Above 65 Htz it's smooth regardless how how high you turn it up?

I just looked them up and see how it's a down firing low woofer...can you unscrew those four wingnuts that hold the top part to the box, then flip it over and inspect? It also looks like the can could come off if necessary, but again I've never worked with these before.
 
Ok I lied but just a little ... just tried turning them up a lot more and could still hear distortion up to about 70hz, then it smoothed out. At higher volume, the distortion was more pronounced at lower frequencies (not surprising). When I say distortion, it's a muffled crackling sound. As for the driver inspection, the bottom is covered with a cage too.
 
robobxman said:
Ok I lied but just a little ... just tried turning them up a lot more and could still hear distortion up to about 70hz, then it smoothed out. At higher volume, the distortion was more pronounced at lower frequencies (not surprising). When I say distortion, it's a muffled crackling sound. As for the driver inspection, the bottom is covered with a cage too.
Click to expand...

Well ... I'm a dumbass. Distortion now worse after the louder tone test (no, I didn't really crank it - but I did turn it up). But I suppose it does point to the vc being damaged.
 
Well these are well regarded and valuable speakers. I'd look into investing into the next step of disassembly. They wen't together somehow, they'll come apart somehow.

Ohm sells upgrade kits for these speakers that include new woofers. Here is a link to the upgrade instructions, which includes the instructions on installation and disassembly.

This might be a great opportunity to have an excuse to make the upgrade :)

https://ohmspeaker.com/site/assets/files/2586/super_4_5000_upgrade.pdf
 
Last edited:
The upgrade is likely very nice, but SO expensive. $2K for the basic upgrade is a little nuts, IMO. I guess I'll have to find a 'parts car' with good drivers. Or maybe Ohm will say they can repair mine. Stay tuned.
 
@Gibsonian I saw that too. I dealt with Ohm to buy new hats for my 4s, and they were great. Just got off the phone with John S. and he was great too - and explained that the $250/pair checkup service will resolve my issues, which he thinks are attributable to failing surrounds. I fessed up to driving the 4s a little hard a few times, but he said it is extremely rare to see spent drivers. He said they are 120 days behind schedule on new sales, but service work like I need is taking about a month. Lastly, a friend of mine and his wife arranged a visit with John a couple of years ago. Again, John and Evan couldn't have been nicer. So my experiences have been really good. If they can resurrect my drivers, I'll be even happier, because I love my 4s :).
 
this video at least shows the guy taking the top off of his Walsh 4 speakers and it looks like once you take the four big Fasteners off and pulls a black top off that underneath there are pastors that allow you to take the Bottom Grill off so that you can have access to the foam surrounds:

in this video at the five minute 48 second mark, it will show what the inside of that black can looks like so that you can see the Tweeter mounted on top the woofer and it also shows the picture with the black can off too.

go to the 6 Minute 11 second mark in this video and you can see where this guy took the can off and gained access to the woofer so it has a really great visual of what you need to work with he did it so you should be able to get to it as well

now if you want to see a video on exactly how to get into the woofer cavity this guy shows taking it all apart at the 31-minute mark
 
Last edited:
robobxman said:
@Gibsonian I saw that too. I dealt with Ohm to buy new hats for my 4s, and they were great. Just got off the phone with John S. and he was great too - and explained that the $250/pair checkup service will resolve my issues, which he thinks are attributable to failing surrounds. I fessed up to driving the 4s a little hard a few times, but he said it is extremely rare to see spent drivers. He said they are 120 days behind schedule on new sales, but service work like I need is taking about a month. Lastly, a friend of mine and his wife arranged a visit with John a couple of years ago. Again, John and Evan couldn't have been nicer. So my experiences have been really good. If they can resurrect my drivers, I'll be even happier, because I love my 4s :).
Click to expand...

@Gibsonian that is my thread Lol.

I'm glad you got clear information from them. The price for round trip shipping & repairs for both cans sounds reasonable. I'm almost positive they will be able to bring your drivers back to life.

My memory didn't serve me correctly about the doped surrounds ; if John says they may need replacing. And with your low frequency issues that is probably the culprit. New foam, some new fuses, and a check over the rest of the components in the driver "hat". You should be all set.

You even got an estimated timeline of product completion, with foresight in regards to current production rates. Interesting.
 
You must log in or register to reply here.
Back
Top Bottom