Using a Main Design as a Center? (1 Viewer)

[John -*-P]

Hey guys, I recently returned to the realm of Home Theatre, only this time its DIY, anyway. I found a project on Parts Express's site under the DIY section mainly Dr. K's MTM's. He states that the crossover was originally modeled for a tower which is what I was planning on build anyway. My only question is how well will this design work for a center channel? I would obviously center the mids and offset the tweeter and use the same porting.

From Parts Express's site, I built the high power version

 

[ThomasW]

The crossover must be redesigned if the speaker is to be used as a center, otherwise the dispersion will be messed up. Darren has stated that he's not interested in doing this.

This of course has been discussed on the PE board.

 

[John -*-P]

Oh Im sorry I didnt realize that PE had a message board, my bad... Man thats too bad, I really wanted to use that as a center. Forgive my ignorance but how does the crossover effect the dispersion rate of the tweeter, I always thought that it was the physical characteristics tweeter itself. Im not all that new to audio, I have played around with it for the last 15 years or so, but now Im trying to get into the more technical aspect of it.

 

[ThomasW]

If you haven't built these I suggest looking at jonmarsh's designs instead. While Darren K is a fairly good designer, jonmarsh is a twice published member of the AES and most of his designs basically define state-of-the art while using parts from PE.

His Modula designs which are also discussed on both the PE and the MAD boards, are VERY good modest costing designs, and he has a specific design for a center. Comparing the standard MTM with the center will go a long way in explaining the difference.

Modula MTM mains
Modula MTM center

 

[John -*-P]

Yeah I saw those on HTGuide, only after I started my project :frowning: Maybe I should look into doing those. Considering I have one cabinets already assembled, oh well. The only reason I wanted to do towers was for music listening.

 

[John -*-P]

Ok, lemme ask you this. Can I use the Modual MTM Mains as Rears? Im very anal about things matching, Physically and sound wise.

 

[ThomasW]

Certainly.....

You can build the mains as minitowers and if you want make the rears bookshelve size. The only difference in the output will be the lowest octaves.

For any of these designs I recommend using a subwoofer.

 

[John -*-P]

Ok, well I think Im still going to finish the Dr. K MTM's before I start these. I hate unfinished projects. As for the subwoofer. I already have, even though its automotive. I basically put the cabash on car audio when I traded in my last car. I had a JL Audio 10W7 sitting here so I bought a plate amp and am now using this as my sub. Even though the box is still the same that I used in my car, it obviously wrong for the room, but works. The sub was the next project after the towers, although recently I just learned....from this forum, that car audio subwoofers do not work that well as HT subs. I never new this. So unless for some strange reason I can find an enclosure that work work well with the W7. Im just going to leave it as as and build something using the Strkye, or Tempest maybe.

 

[ThomasW]

A 10" driver in a car plays pretty loud because of cabin gain. Unfortunately it's a drop in the bucket for most rooms.

Stryke now known as AE Speakers is having so issues so drivers aren't being shipped.

Both Adire and Ascendant are between production runs, so they don't have product either.

There are very good drivers available from Todd at www.oaudio.com. And the new alu cone 12" from PE are pretty amazing for the very modest price

 

[John -*-P]

Ok well after some long deliberation. I think im going to start the Modula's, but here is where the problem lies. When I had originally planned on doing a HT, I was going to be using the Polk lsi9's. Then the idea of build my own was so much more appealing, and cheaper. Now I don't mind the cost and Im sure they sound good, but after pricing all the components just for the XO for the Modula MTM Mains, it comes to just over $400 for both plus the cost of the drivers yet too. Which now the Modulas are going to cost more then the lsi9's that I originally looked at. I know Jon uses the best components in his XO'a and to some people he may overbuild them, but when he explains what and why hes doing what hes doing, it all makes sense. So I guess my question is how much will it effect the sound if I swapped XO components to cheaper pieces with same value? Like Dayton caps instead of Theata and Auidocaps? I figured it would cost around $790 for the XO parts for the rears and the mains. Plus the center XO parts still have to be bought. Like I said before though, I dont mind paying the extra cost, and Im sure its worth it, its just a little curiosity I guess.