Input on some MTM's

[black300zx]

Hopefully I'll start building a new set of MTM's within the next month.

What I know:
Sealed MTM using peerless exlusive 7's

What I'm 99% sure of:
Seas 27tbfc/g tweeter

I'm running the exclusive 8's in my car, and love them, thus the reason I'm using the 7's for the woofers for these mtm's. I've heard great things about that seas tweeter, so I've been planning on going with it for a while.

Just today I ran across the Vifa XT ring radiator tweeters here:
http://www.madisound.com/cgi-bin/ind...d=5425185.9462

Opinions on them? Are they in the same league as the seas? From what I've read about the seas, they seem to be better than anything in their price range. What I read about the vifa XT's today sounded pretty good too, so I'm a little unsure of how I want to go now.

Any input?

[joe carrow]

I have the Seas tweeter, and it's quite good. I believe that the XT25 is competitive, but won't be able to cross as low. If you have a steep slope, the Seas tweeter can cross quite low.

If it was a simple MT, I'd tell you to go with whichever you like. Since you want the MTM arrangement, I suggest the Seas and a low crossover.

The peerless drivers look awesome- I think you've picked a really outstanding set of drivers for a home system.

[pinkmouse]

Have you designed many crossovers? if not, I wouldn't recommend an MTM, they are pretty fiddly to get right.

[sdclc126]

Have you been to www.zaphaudio.com ?

You can get loads of info on both tweeters, including builds he uses them in. He doesn't have any designs using the Exclusive drivers, but he does review them. The BAMTM is his MTM design with the SEAS tweet - maybe the Dayton woofers aren't in the same league as the Peerless, but they are excellent nonetheless.

It's worth considering if you are not prepared to design your own crossover.

[tinitus]

I have been listening to XT25 fore 5 years now, and its a great tweeter - but I would best describe it as a bit of a "toy" tweeter

Should I recommend anything better it could be ACCUTON
I have had both C11 and C22, but theres a new interesting C45 coming

Well, theres a Fostex FT28D I would like to try

[tinitus]

Ahh, yes, the new ScanSpeak D3004/660000 looks to be VERY interesting - I am sure its expencive, but might be worth it

And woofers I might be looking at the new RAW 6", or maybe Hemp, if they ever will be available

Those RAW 6" would take some EQ, and make some fantastic bass notes

I think such drivers would be the only reason to "go solo" and make my own

[Al Garay]

There are many good options. You don't have to break the bank. Check out this Usher tweeter:

USHER 9950C-15 shielded $67, very rugged, strong posts

http://www.partsexpress.com/pe/showd...number=276-610

It's the tweeter used in the Exodus kits and after a couple of years, I'm very pleased.

The Hiquphon OW4 would also be a good choice but more expensive.

[black300zx]

thanks for the input guys. I think I'm gonna stay with the Seas tweeter.

As for x-over design, I've built a set dayton 8 mtm's (pre-designed x-over obviously), and I also made a custom passive x-over for my sister car for adire sf7 midbasses and dayton classic 1 1/8" silk domes. They came out pretty good, I just need to attenuate the tweeter a bit. I have the resistors for the l-pad, I just need to get around to figuring out how much I need to attenuate them.

I have speaker workshop, and I should be getting a behringer mic/pre-amp combo this month. These MTM's are gonna be a long term project. I'm going to have the crossovers outboard of the enclosures so I'll be able to tweak or rebuild them easily until I get it right. Additionally, this will allow me to easily run them active if I desire.

[soongsc]

Originally posted by pinkmouse
Have you designed many crossovers? if not, I wouldn't recommend an MTM, they are pretty fiddly to get right.

I second this. Recently trying a few MTM designs, I hear two strikes on a drum that should be one. Pretty hard to get them righ unless you probably consider one as the main bass and the other for baffle step compensation like in some of Zaph's designs.

[joe carrow]

I think that if you're willing to consider it a high cost learning experience, and don't let yourself get frustrated, your chance of success will be reasonably high.

The woofers don't have metal cones, so they should be much more forgiving if you don't lowpass them sharply enough, or at a low enough frequency. Granted, it will mess up the dispersion if you let them play too high, but it will be nowhere near as bad as if you messed up on a metal cone. Also, if you don't play extremely loudly, the tweeter should be able to survive some fairly humorous mishaps, and a 4th order crossover down to 1500 hz, or 2nd down to 2000. Heck, I wouldn't be surprised if you got a first order crossover to work (definitely not with these woofers, of course) below 5k.

If you just want to be darn sure that you get top notch performance, then there are plenty of excellent MTM designs using the Dayton Reference RS180 with various tweeters, including the Seas tweeter.

Good luck!