Any chance of making this cheap MTM module work?

martyh

Member
Paid Member
2004-02-01 2:58 am
Wisconsin
Since the Tymphany TC9FD went on sale I ordered 4. I also have a box full of peerless CT 62 H tweeter pulls lying around so I figured why not a super cheap MTM module. I’ve been reading about D’Appolito layouts for a few days and have come up with some conflicting info on workable spacing.

I have the tools to measure the results and enough determination to work through a few crossover iterations but would rather not waste the metal and time to machine a faceplate for them that has no chance of working out.

Just wondering before I get started if I am off on the wrong track here. I’m thinking of a crossover circa 2KHz between parallel mids and the tweeter.

Thanks in advance,
Marty

MTM_zpsod857hmq.jpg


Tweeter http://spicaspeakers.com/pdfs/peerless-801730.pdf

Mid http://www.parts-express.com/pedocs/specs/264-1062--tymphany-tc9fd18-08-spec-sheet.pdf
 
The spacing allows you to xo anywhere above 1100Hz but the CTH starts falling off at 2k so I would go a bit above that. You need to run some simulations to see where the polar dispersion would best match up. I think 3.5kHz might work well to keep the xo out of the presence region and let the Tc9's beautiful mids handle all smooth mids it's so good at. Two TC9's in parallel are good for 91dB at 2.83v. So that matches almost perfectly SPL wise with this 90dB tweeter. But below 1k there will be baffle step falloff circa 4 to 5dB so you may need a shelving filter on TC9 and pad CTH down to about 86 to 87dB.

Looks like a good plan. I think you will be pleasantly surprised at how good it can sound. If using DSP Xo. Look at using a Harsch XO for quasi transient perfect.

Don't run the TC9'd below 350Hz for lowest distortion.
 
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martyh

Member
Paid Member
2004-02-01 2:58 am
Wisconsin
Thanks for the advice. Started building the plates out of aluminum but they rang like a bell so ended up making them from CE phenolic instead. I'll try the higher XO first. Do you think is worth notching out the resonance in the TC9 if I use a 3rd order passive XO on them? Crossing to the woofer is going to be electronic so should be pretty easy to dial in.
 

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