Morel mdt 33 for HT use

[Dick West]

I am using a pair of MDT-33 tweeters in my L&R speakers which are MTMs with 1st order series xovers. I chose the Morels because they are very robust and have a low Fs, qualities necessary for a series 2500 hz 1st order xover in a dynamic and often loud HT environment.

The L&R speakers are 28" away from the 27" Sony TV and no effects are noted from their magnetic field.

My center channel MTM uses a pair of shielded M-130s from GR Research with a Morel MDS 37 tweeter which is, again, robust, with a low Fs.

All in all, I would say go for it on your tweeters.

I selected series xovers for simplicity and all 3 speakers use very similar xovers to make their phase shifts around the xover point as much the same as possible to maintain the 3-D illusion of surround sound.

[Hezz]

Thanks Dick,

I now feel confident that a first order at 5.2 kHz will be fine for the HT environment with that driver. This is assuming a parallel filter. Tell me, does the series filter attenuate the out of pass band frequencies at a higher rate than the parallel network.

[Dick West]

1st order series xovers will attenuate more than 6db/oct, depending on the circuit's Zeta. Go here to read about them:

http://www.partsexpress.com/resource...er/primer.html

Also, here is a list of many fine articles about series xovers:

http://users.tpg.com.au/users/gradds...oss-overs1.htm

Many claim a series xover will hold phase of the two drivers more in step with each other through the xover region than parallel xovers. I find series xovers of the L&R&C speakers to help with the 3-D sense of space as I make all 3 of mine identical.

The spreadsheet available at Andy's site (above) is very helpful and is what I used to build my xovers, before tweaking them slightly. But, proper selection of drivers is vital.