I just traded a bike for someone else's old DIY project. I got some Fostex FE206EN with the horn cabinets suggested in the specs. One driver plays slightly quieter and has a mechanical sounding buzz or rattle in the mid range. I have cleaned contacts, inspected and compared both drivers, swapped cabinets, but the issue remains on the single driver. I've never dealt with a whizzer cone arrangement before so I'm treading lightly.
I'll be back tomorrow but tonight this has me whooped.
I'll be back tomorrow but tonight this has me whooped.
Take the driver out of the cabinet, and put it facing up on a table.
Push down gently on the outside of the cone. Start with pushing on two points opposite each other, so the cone should move straight down.
That'll probably scrape.
Now, push down at one side, and work your way around the edge of the cone. You'll probably find one side scrapes really badly, and opposite that the cone moves freely.
If that's the case, the suspension has sagged a little and let the coil touch the magnetic gap.
The fix is to keep track of the point where the cone moves freely, and re-mount the driver so that point is at 12 o'clock.
Chances are it'll be a 180-degree rotation, but the cabinets may have been stored on their sides for a while.
You can simply wait for the weight of the cone to re-align things, or you could try applying gentle heat to soften things a little. I'm thinking a hairdryer set to "low", but I haven't tried that myself.
Chris
Push down gently on the outside of the cone. Start with pushing on two points opposite each other, so the cone should move straight down.
That'll probably scrape.
Now, push down at one side, and work your way around the edge of the cone. You'll probably find one side scrapes really badly, and opposite that the cone moves freely.
If that's the case, the suspension has sagged a little and let the coil touch the magnetic gap.
The fix is to keep track of the point where the cone moves freely, and re-mount the driver so that point is at 12 o'clock.
Chances are it'll be a 180-degree rotation, but the cabinets may have been stored on their sides for a while.
You can simply wait for the weight of the cone to re-align things, or you could try applying gentle heat to soften things a little. I'm thinking a hairdryer set to "low", but I haven't tried that myself.
Chris
Thanks for the reply - sounds like I have some tinkering to do. Do you mean I should be pushing on the whizzer cone or the woofer cone?
The main woofer cone. The whizzer is too small to get any sideways leverage - we want to apply a little turning moment about the coil to check if the alignment is out.
Chris
Chris
Hey Chris - just got around to trying this all out. I found the asymmetry you suspected. I have the driver mounted so it'll hopefully even out. There is already an immediate reduction in the rattle. I'll keep listening and leave it overnight before in case heating proves unnecessary. Thanks for the fast and knowledgeable help. I've never owned or interacted with big speakers like these. I don't have words for the sound coming from these compared to the bookshelf speakers I used to think were good. Totally different compared to the ELACs I had connected to my amp camp amp.
The cone is still rubbing, although noticeably less, after 24 hrs. Should heat be applied to where the woofer meets the folded dampening? Or from the front front with the speaker mounted in position in the cabinets? I'll probably wait at least another day before trying the heat.
If gravity alone is making progress, leave it another few days and you should be golden.
If it's been a while and still not aligned, I'd apply heat around the rear of the cone. Get the soft parts warm to the touch and allow gravity to help reset things as they cool.
Chris
If it's been a while and still not aligned, I'd apply heat around the rear of the cone. Get the soft parts warm to the touch and allow gravity to help reset things as they cool.
Chris