M&K v125 Subwoofer Tweaks (and wiring question)

Tweakers' Asylum

Tweaks for systems, rooms and Do It Yourself (DIY) help. FAQ.

When I opened up my subwoofer this weekend, I found both good news and bad news. First the good:
It looks as though M&K actually had a clue about the effects of vibration on electronics when they designed this powered subwoofer more than 10 years ago. Some of the larger capacitors had hot glue between them, helping to keep them from vibrating independently of the board. Also, the boards are mounted with cork washers and aluminum spacers instead of the usual plastic and steel. Thumbs up!
Now the bad news. The screws mounting the amplifier to the cabinet were all loose. Although this was no surprise, it was not good for several reasons, the least of which being that the airtight seal of the cabinet can be compromised if these screws become too loose. There was no type of sealing material between the amp and cabinet, so I applied a thin layer of silicone sealant to the edge of the cabinet before reinstalling the amplifier. If I had more space in my listening room, I would consider mounting the amp externally to the cabinet.
Upon removing the driver, two more problems were found. First, only four screws were holding the driver in place (the driver itself has eight mounting holes - the cabinet only has four holes drilled, each with retaining nuts pressed into the inside of the cabinet). I verified this was not an optimal scheme by simply pulling up on the driver at one of the unused mounting holes with just my finger - sure enough, I was able to deform the driver slightly. Not good! When I replaced the driver, I used four additional drywall screws so that the driver was held down at all eight mounting points. A quick calculation says it's held down roughly twice as secure now.
While the driver was out of the cabinet, it was hard to not notice that the shielding magnet (I'm assuming that's what this was - it's an additional magnet attached to the back of the driver such that it opposes the force of the driver magnet) had fallen off. I reattached the magnet using epoxy. I had to place something very heavy on top of the shielding magnet to keep it in place while the epoxy cured.
Noting the less than liberal use of batting inside the cabinet, I placed some additional batting in there.
The result of these very easy tweaks should be no surprise - bass got deeper and tighter.
While I had the cabinet open it was very obvious that better wiring could be employed in this subwoofer. Before going that route, I am hoping to get some wiring recommendations from you folks. Specifically, what wires are recommended for power and what wires for signal?
While I figure out what wire to use, I'll have to practice soldering.....
One more note - I noticed the 'cage' around the driver was quite resonant. I ran out of thime this weekend, but I will try damping it with something like Dynamat (whatever I do will be reversible since I don't yet know if the results will be pleasant). Has anyone tried damping the cage on a bass driver before with good results?
Happy Hacking,
Pete

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Topic - M&K v125 Subwoofer Tweaks (and wiring question) - pburant 13:45:35 03/18/03 (3)

I forgot about spiking the sucker! - pburant 12:28:40 03/19/03 (0)

Re: M&K v125 Subwoofer Tweaks (and wiring question) - sam9 15:37:50 03/18/03 (1)

Thanks! - pburant 04:22:36 03/19/03 (0)

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