DIY center featuring JL Audio 6.5" Mid/Woofers?

[Darth Mike]

I want to build a center as my first true DIY speaker for a couple of reasons:

• Building a single center speaker is an easy task when compared to building a pair of speakers to exacting measurements
• I have most of the components to do the job already
• Even if this project is a failure, all the parts were just sitting around anyways so I won't lose much
• My center is the weakest link of my system, so even a marginal improvement will make this project a sucess
• If it comes out to be a sucessful project it will build my confidence to build more speakers, namely the next weakest link in my system, a subwoofer, which I also already have most of the parts for

Click to enlarge.
They will end up this color.
I have these X-overs laying around after my white-van speaker mods, and since they will be used on actual dual 4ohm drivers in series an 8-ohm x-over will do fine, the white-van specials were so innefficient they weren't able to be wired in series.
Here are the drivers I'll be using.
Heres the woofer for that sub build I mentioned...old school kicker seperates series sounded SO nice, I bet it will do well in my room too...

Now for a few questions:

Should I build this MTM style? I know it's bad for dispersion, but even higher end companies use MTM centers. If not what would a better idea be?

Can someone reccommend a tweeter that will match well to my mains? I use Infinity Qe's with the EMIT tweeters, and since the only part I will be buying is a tweeter I can afford a nice one...

Should I use multiple tweeters? If so how many, and what configuration?

Would front or rear portng be beneficial? If so which (front/rear)?


Thanks folks,
-Mike

 

[Sheep]

MTM is not in-general a bad design, but you have to design it so it around that dispersion affect.

Example: Energy's Veritas Center uses a tapered crossover to eliminate this effect.

I would only use a crossover designed to work with those drivers. And wheres the tweeter?

SheepStar

 

[Darth Mike]

MTM is not in-general a bad design, but you have to design it so it around that dispersion affect.

Example: Energy's Veritas Center uses a tapered crossover to eliminate this effect.

I would only use a crossover designed to work with those drivers. And wheres the tweeter?

SheepStar

Read the questions bro', I am asking for advice on a tweeter to use. The crossover frequency of the x-over I was going to use seemed to be sufficient @~3kHz, I don't see how it would differ from one I made for it...

 

[jaxvon]

Is the Infinity tweeter a ribbon of some sort? If so, Parts Express carries a variety of ribbon and planar tweeters. Of course, if you wanted to be *really* anal, you could just choose a highly linear/low distortion planar tweeter, such as one made by BG, measure your Infinity speakers, then just use a good parametric equalizer to achieve a similar response characteristic (at least in terms of frequency response, distortion is another matter). However, that would take some time to set up the measurements and such. Still, I think it would be the optimal choice.

As for good sound, JL Audio makes good drivers. They are often overpriced, in my opinion, but they tend to be very linear and of high quality.

You should also be aware that you will need to do something to compensate for the magnetic field radiated by your JL Audio drivers. They do not appear to be shielded. If you plan on placing your center near a CRT TV, they will need a shielding can, bucking magnet, or some type of electromagnetic shielding that will prevent the field from straying outside of the speaker cabinet.

 

[Darth Mike]

Is the Infinity tweeter a ribbon of some sort? If so, Parts Express carries a variety of ribbon and planar tweeters. Of course, if you wanted to be *really* anal, you could just choose a highly linear/low distortion planar tweeter, such as one made by BG, measure your Infinity speakers, then just use a good parametric equalizer to achieve a similar response characteristic (at least in terms of frequency response, distortion is another matter). However, that would take some time to set up the measurements and such. Still, I think it would be the optimal choice.

As for good sound, JL Audio makes good drivers. They are often overpriced, in my opinion, but they tend to be very linear and of high quality.

You should also be aware that you will need to do something to compensate for the magnetic field radiated by your JL Audio drivers. They do not appear to be shielded. If you plan on placing your center near a CRT TV, they will need a shielding can, bucking magnet, or some type of electromagnetic shielding that will prevent the field from straying outside of the speaker cabinet.

I think instead of the trouble of matching a tweeter to the Infinity EMIT tweeter, I may buy a reconditioned EMIT off ebay and just use that and be done with it.

I know the JLs are way overpriced, but I got them free in a car I bought to resell, that's why they aren't exactly in top condition as far as looks go, but boy do they sound nice.

As far as magnetic shielding goes, I'm using a little 24'' CRT as a go between while I'm saving for a 60'' DLP rear projection. My entertainment center is quite large as compared to my TV and sufficient space is available to prevent issues.