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Re: MCM 55-2421 came unglued in a T18. What alternatives??
Posted: Mon Oct 15, 2012 8:11 pm
by But it Hertz
Is it strange to say they look, you know; kinda sexy in there?
Re: MCM 55-2421 came unglued in a T18. What alternatives??
Posted: Mon Oct 15, 2012 9:52 pm
by shawn_g
But it Hertz wrote:Is it strange to say they look, you know; kinda sexy in there?
If it's wrong, I don't want to be right.
Re: MCM 55-2421 came unglued in a T18. What alternatives??
Posted: Wed Oct 17, 2012 9:52 am
by But it Hertz
So the driver is supposed to arrive today. I have been thinking. Seeing as these speakers work so well and yet are so far from the recommended specification... then there is no need to break the driver in is there? I could save myself 12 hours and just go for it?
Right?
Re: MCM 55-2421 came unglued in a T18. What alternatives??
Posted: Wed Oct 17, 2012 10:00 am
by Bill Fitzmaurice
But it Hertz wrote:So the driver is supposed to arrive today. I have been thinking. Seeing as these speakers work so well and yet are so far from the recommended specification... then there is no need to break the driver in is there? I could save myself 12 hours and just go for it?
Right?
Wrong.
The driver will eventually break in with use, but it won't work optimally until it does.
Re: MCM 55-2421 came unglued in a T18. What alternatives??
Posted: Wed Oct 17, 2012 10:04 am
by But it Hertz
Bill Fitzmaurice wrote:Wrong.
The driver will eventually break in with use, but it won't work optimally until it does.
OK thanks Bill

Re: MCM 55-2421 came unglued in a T18. What alternatives??
Posted: Wed Oct 17, 2012 11:00 am
by shawn_g
I didn't break in the Dayton driver on my first T-18 and it sounded noticeably better after a week or so of use (pretty sure it wasn't just in my head).
This is an interesting read on the topic:
http://www.gr-research.com/burnin.htm
Re: MCM 55-2421 came unglued in a T18. What alternatives??
Posted: Wed Oct 17, 2012 11:06 am
by But it Hertz
That's a really interesting article.
I might take this opportunity to measure the SPL response before & after break in. Might be something interesting to see?
FTA: Most all manufacturers recommend 40 to 50 hours of burn in time to reach an acceptable level of stabilization.
Wow, that's a lot... I was convinced my MCM 55-2421 was sounding particularly fantastic just before it came unglued... but I was messing with the miniDSP. I thought I had just perfected the settings and was feeling really pleased with myself. I reckon it had about 50 or so hours on it.
Maybe if I can measure a difference in the SPL chart from new to 12 hours of breaking in... I'll consider pulling it out and giving it another 12 hours or so break in and measure again.
Is it worth playing? Anyone interested?
Re: MCM 55-2421 came unglued in a T18. What alternatives??
Posted: Wed Oct 17, 2012 2:29 pm
by But it Hertz
bassmonster wrote:Can you please measure the driver depth once you remove the rubber on the magnet assembly?
Here you go!

Re: MCM 55-2421 came unglued in a T18. What alternatives??
Posted: Wed Oct 17, 2012 2:36 pm
by But it Hertz
Soooooooo. Bummer. I don't think it will fit.
Physically I can get it in the box but i need to rework the cover. That's the easy bit.
But the holes don't line up!! Booooo. The Infinity is a little bit bigger all the way around. Here it is face to face with the MCM.
This is the money shot. All the holes are slightly in the wrong place due to the slightly larger diameter of the Infinity!
Any clever suggestions?
Re: MCM 55-2421 came unglued in a T18. What alternatives??
Posted: Wed Oct 17, 2012 2:51 pm
by But it Hertz
I have a right angled drill that fits nicely in the hole.
How about I leave the existing t-nuts there, I used gorilla glue to set them in place, they aren't going anywhere.
Fill the old t-nuts with PL and drill new holes for a new set of t-nuts.
I can use a small G clamp to press the new T-nuts in place.
I still have one of my practice baffles. The speaker hole is perfect.
Or shall I just get another 55-2421 and keep the infinity for the next project?
Waaaaaaaaaaaaaaaaaaaaaa

Re: MCM 55-2421 came unglued in a T18. What alternatives??
Posted: Wed Oct 17, 2012 4:15 pm
by Bruce Weldy
But it Hertz wrote:
Fill the old t-nuts with PL and drill new holes for a new set of t-nuts.
Use epoxy to fill 'em .....PL doesn't like metal.
Re: MCM 55-2421 came unglued in a T18. What alternatives??
Posted: Wed Oct 17, 2012 4:30 pm
by Gregory East
L clamps, not at all fussy about positioning. I got no idea how you can get new t-nuts installed in a finished cab but at least with L clamps the new holes don't have to be spot on.
Re: MCM 55-2421 came unglued in a T18. What alternatives??
Posted: Wed Oct 17, 2012 4:56 pm
by bassmonster
But it Hertz wrote: Here you go!
Thanks! I might have to build some BFM subs with these...

Re: MCM 55-2421 came unglued in a T18. What alternatives??
Posted: Thu Oct 18, 2012 12:55 am
by But it Hertz
Gregory East wrote:L clamps, not at all fussy about positioning. I got no idea how you can get new t-nuts installed in a finished cab but at least with L clamps the new holes don't have to be spot on.
L clamps?? Got any pictures?
Re: MCM 55-2421 came unglued in a T18. What alternatives??
Posted: Thu Oct 18, 2012 1:01 am
by Bas Gooiker
But it Hertz wrote:Or shall I just get another 55-2421 and keep the infinity for the next project?
Waaaaaaaaaaaaaaaaaaaaaa

Keep it, there is always a next project!!
