Driver mounting/installation issues

StevenZ · 19th October 2011, 12:29 AM

Guys I need help. I just finished a pair of beautiful pensils for my 7.3's and as soon as I hooked them up there was massive distortion. I tried them on another amp as well and the same thing happens. Distortion on low volumes, it's crackly and fuzzy and just down right horrible. I haven't touched the drivers, I haven't even broken them in.

I thought that maybe some of the polyfil may be touching the back of the cone so I took off the back and removed the fill. Same thing. I thought maybe it was my amp. So I hooked it up to another amp and same thing. What do I do? Could it be that both of my amps aren't able to support a 6 ohm load? That doesn't seem possible as they're both perfectly happy with both 4 and 8 ohm speakers. I'm at a loss. I was hoping to start break in tonight but am riddled by the overwhelming distortion when I play the speakers.

Please help!

buzzforb · 19th October 2011, 12:34 AM

Nope, something is wrong. Did you check the basics like solder joints on drivers, good fit of drivers in recess of baffle? It could be the extra ring that comes with them. Did you put it on without using adhesive thinking the screws would hold it?

silverhairbp · 19th October 2011, 12:42 AM

Doesn't sound like amps to me.

When you cut / routed the holes for the drivers, were all the surfaces flat? Could it possibly be that the frame(s) was warped a bit when the drivers were mounted? Did you try loosening the screws a bit to see of the distortion continued?

I wonder if removing the drivers from the boxes and just running them with a low-power signal will produce distortion...

StevenZ · 19th October 2011, 12:53 AM

All the solder joints were solid. I didn't use the outer ring that comes with the drivers. The drivers fit perfectly if not a tiny bit snug. The cutout has a 1/8" round over on the inside edges. I really don't understand what could be happening. Tomorrow when I have more time I'll take one of the drivers out and inspect it for damages and try hooking it up without an enclosure to see if that helps to minimize or eliminate the distortion. I'll re-solder all the joints and try to sand off a little on the cutout to make it loose. Any other ideas?

markaudio · 01:02 AM

Hi Steven,

As per members Buzzbob and Silver's advice:

Carefully check the drivers are mounted flat and you've not over-tightend the mounting screws. If the driver's power-trains are pulled out of alignment, you're hearing is coil rub. Running the drivers in this state will cause coil circuit failure in a matter of minutes. The drivers will be ruined.

Take the drivers out of the cabinets. Run them in free air on low volumes to check their operation. Then check your cabinet driver mounts. They must be flat.

When you re-install, take care not to over-tighten the screws. Use the edge of a straight steel ruler (or similar) to eye-ball the front of the driver frame as you gently tighten the screws. Make sure the frames remain flat.

If possible, post some high quality pics of the driver mounts in your cabinets.

If you still have distortion, then the problem is elsewhere, possibly on the source side.

Thanks
Mark.

StevenZ · 19th October 2011, 12:59 AM

Thanks Mark, i'll see what I can do.

StevenZ · 19th October 2011, 01:06 AM

You guys were right! They were screwed in too tight and everything sounds great now. Thanks so much!

silverhairbp · 19th October 2011, 01:10 AM

I was just about to suggest that the distortion might be from the source. When further tests are made, make sure you're getting a clean signal from your upstream components.

buzzforb · 19th October 2011, 01:10 AM

I would still make sure that the roundover edge left by many router bits is not making contact with the outer part of the flange of the driver. This would mean that most of the pressure was on that small outer rim. It would affect the sound of the drivers.

StevenZ · 19th October 2011, 01:15 AM

Well the distortion wasn't from the source as I was just playing another set of speakers with it immediately before I hooked up the 7.3's. I will still remove the drivers and sand a little off the inside edge of the cutout to let it be loose instead of snug. I believe the whole problem was from over tightened screws as when I released all the pressure all distortion ceased. Everything is great now. You guys are the best.

19th October 2011, 12:29 AM	#1
StevenZ diyAudio Member Join Date: Jul 2010	Driver mounting/installation issues Guys I need help. I just finished a pair of beautiful pensils for my 7.3's and as soon as I hooked them up there was massive distortion. I tried them on another amp as well and the same thing happens. Distortion on low volumes, it's crackly and fuzzy and just down right horrible. I haven't touched the drivers, I haven't even broken them in. I thought that maybe some of the polyfil may be touching the back of the cone so I took off the back and removed the fill. Same thing. I thought maybe it was my amp. So I hooked it up to another amp and same thing. What do I do? Could it be that both of my amps aren't able to support a 6 ohm load? That doesn't seem possible as they're both perfectly happy with both 4 and 8 ohm speakers. I'm at a loss. I was hoping to start break in tonight but am riddled by the overwhelming distortion when I play the speakers. Please help!

19th October 2011, 12:58 AM	#5
markaudio diyAudio Member Join Date: Nov 2008	Hi Steven, As per members Buzzbob and Silver's advice: Carefully check the drivers are mounted flat and you've not over-tightend the mounting screws. If the driver's power-trains are pulled out of alignment, you're hearing is coil rub. Running the drivers in this state will cause coil circuit failure in a matter of minutes. The drivers will be ruined. Take the drivers out of the cabinets. Run them in free air on low volumes to check their operation. Then check your cabinet driver mounts. They must be flat. When you re-install, take care not to over-tighten the screws. Use the edge of a straight steel ruler (or similar) to eye-ball the front of the driver frame as you gently tighten the screws. Make sure the frames remain flat. If possible, post some high quality pics of the driver mounts in your cabinets. If you still have distortion, then the problem is elsewhere, possibly on the source side. Thanks Mark. Last edited by markaudio; 19th October 2011 at 01:02 AM.

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19th October 2011, 12:34 AM	#2
buzzforb diyAudio Member Join Date: Oct 2010 Location: Burlington, NC	Nope, something is wrong. Did you check the basics like solder joints on drivers, good fit of drivers in recess of baffle? It could be the extra ring that comes with them. Did you put it on without using adhesive thinking the screws would hold it?

19th October 2011, 12:42 AM	#3
silverhairbp diyAudio Member Join Date: Feb 2011	Doesn't sound like amps to me. When you cut / routed the holes for the drivers, were all the surfaces flat? Could it possibly be that the frame(s) was warped a bit when the drivers were mounted? Did you try loosening the screws a bit to see of the distortion continued? I wonder if removing the drivers from the boxes and just running them with a low-power signal will produce distortion...

19th October 2011, 12:53 AM	#4
StevenZ diyAudio Member Join Date: Jul 2010	All the solder joints were solid. I didn't use the outer ring that comes with the drivers. The drivers fit perfectly if not a tiny bit snug. The cutout has a 1/8" round over on the inside edges. I really don't understand what could be happening. Tomorrow when I have more time I'll take one of the drivers out and inspect it for damages and try hooking it up without an enclosure to see if that helps to minimize or eliminate the distortion. I'll re-solder all the joints and try to sand off a little on the cutout to make it loose. Any other ideas?

19th October 2011, 12:59 AM	#6
StevenZ diyAudio Member Join Date: Jul 2010	Thanks Mark, i'll see what I can do.

19th October 2011, 01:06 AM	#7
StevenZ diyAudio Member Join Date: Jul 2010	You guys were right! They were screwed in too tight and everything sounds great now. Thanks so much!

19th October 2011, 01:10 AM	#8
silverhairbp diyAudio Member Join Date: Feb 2011	I was just about to suggest that the distortion might be from the source. When further tests are made, make sure you're getting a clean signal from your upstream components.

19th October 2011, 01:15 AM	#10
StevenZ diyAudio Member Join Date: Jul 2010	Well the distortion wasn't from the source as I was just playing another set of speakers with it immediately before I hooked up the 7.3's. I will still remove the drivers and sand a little off the inside edge of the cutout to let it be loose instead of snug. I believe the whole problem was from over tightened screws as when I released all the pressure all distortion ceased. Everything is great now. You guys are the best.