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Discussion Starter #1
I've got a set of cerwin vega m-100 towers and the mids/tweeters are starting to get a little old. these towers have always had relatively poor midrange, and i'd like to see what i can do to fix em up. I guess the requirement for the mids would be a sealed back driver so that i don't have to do too much work to the cabinets to make it sound decent.

The fun part about these speakers is that the mids/highs are way more sensitive than the woofers to begin with! (at least in their peaks)

Woofers are good to about a 96db1/w sensi, they cross at 500hz and 3500hz.

I sent an email to cerwin vega to get the old spec sheet on these monsterous towers and this is what they sent me back.

CERWIN VEGA M-100
DESCRIPTION: 15” 3-Way Loudspeaker
FREQUENCY RESPONSE: 30 Hz – 20 kHz
POWER HANDLING: 5/400 Watts RMS (Min/Max)
SENSITIVITY: 107dB (1 Watt @ 1 Meter)
NOMINAL IMPEDANCE: 4 Ohms
LF DRIVER: 15” Die-Cast Frame / 2” VC
MF DRIVER: 6” Cone (2)
HF DRIVER: 1” Phenolic Dome Horns (2)
PROTECTION: Circuit Breaker (HF & MF)
LEVEL CONTROLS: Tweeter and Midrange
CROSSOVER POINTS: 500/3500 Hz.
DIMENSIONS: 35.3” X 18” X 17.75” (H X W X D)
WEIGHT: 92 lbs.

As you see, there are Two tweeters, and two mids on these cabinets. I'm sure that the 107 sensi is a peak rating and i highly doubt its anywhere close to that. I have guesstimated the sensi to be about 96db and think this is a range to aim for.

Any suggestions on drivers?

The woofers are in perfect condition and i have no reason to replace them, they make it down to 40 with authority, and thats perfect for my subwoofer. I'm just absolutely tired of the muddy midrange and harsh highs, i would love to update them.
 

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Changing the drivers will probably mean a change in the Xover which means a different Xover, unless you can find drivers with the exact same specifications, which would be next to impossible.
 

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96 db/sensitivity tends to indicate a lack of baffle step correction in the crossover. I suggest you get a Behringer Feedback Destroyer and an external amp. Use this to correct the crossover.

For your boxes. You will want to add braces and improve damping. R11 or R19 is very cheap at home depot. You could use that to treat the cabinets. Face it paper out so the fibers don't fly all over the speaker interior.

For bracing red oak is preferred and is pretty easy to use. Put a rib at every 4 inches inside the box. You'd need to add braces before putting the fiber glass in, Usually 8 feet of red oak 1 x 2 is enough for a speaker cabinet.

The combination of the BFD, Damping and bracing will improve the speakers a lot should you want further improvement drivers will need new crossovers in most cases.

For glue get titebond original and 3m 77.
 

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Discussion Starter #4 (Edited)
couldnt i just use a pair of sealed back midranges with higher sensitivity to bring out the midrange? (seems kinda like a no-brainer to me)
something like this:
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=290-542

Another question, how would the feedback destroyer help? i know it would work if i used an ultra-drive digital crossover, but im not sure how to implement a bfd. doesnt an electronic crossover require one amp per frequency range? so one for bass, one for mids, and one for highs?

Oh, and on a side note, one of the tweeters is blown on one of the towers, so replacements are required for the high end at the bare minimum.
 

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Crossovers are designed for the drivers and the enclosure they are in. You can swap out the drivers but it will not sound correct. :)

If you really want to change out the drivers I suggest contacting madisound and having them design a crossover, based on their replacement drivers. http://www.madisound.com/services/leap.php

Have you thought about building a nice DIY speaker? It would be a fun project and probably not much more money than replacing the drivers in the CV's?
 

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Discussion Starter #6
ive got a diy center/rears currently, the mains are next, but i can't get Wifey approval to change the cabinets. I figured i'd cheat by keeping the same cabs and just bringing out the mids/highs. I'm not afraid to look into designing new crossovers or going active, i just don't wanna buy another multichannel amp. (my power draw is quite harsh on a 15 amp breaker.)

the cerwin vega crossovers are getting old and i know they only last so long before the caps dry up.
 
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