DIY Centre Speaker advice

[sunrise3500]

I'm looking at doing a DIY Centre speaker to replace my current MTM centre.

Thinking of heading down the W-MT-W path.

Bit torn between getting something like 6.5" woofers (seen some 7" vifa on ebay for a good price, dunno if they're too big to suit a centre), 2" tweeter, 5" midrange.

Alternatively, for something to better match my fronts (which are bookshelves), what if I'm to get another set of the bookshelves, and rip out the woofer from it (they're 5"), and rip out a 4" midrange from my current centre speaker and take a out the tweeter and redo it, and then make crossovers. Doing this would also be significantly cheaper. Dunno if that's an idea that's just a waste of time and money or what..

any opinions would be appreciated, thanks!

[Inductor]

The first idea that comes to my mind when doing that (buying off-the-shelf - or ebay -) one (you) must know the T/S parameters of a driver, so, driver model parameters, not the speaker cabinet's. So, wich manufacturer is specifying that (driver's brand & models they are using inside)? Or then you bring them home and measure them with Lab equipment.

[sunrise3500]

ohh i figured i could work out the dimensions of the cabinet currently used for them and use that to work out how big to make the centre

[Inductor]

Originally posted by sunrise3500

Alternatively, for something to better match my fronts (which are bookshelves), what if I'm to get another set of the bookshelves, and rip out the woofer from it (they're 5"), and rip out a 4" midrange from my current centre speaker and take a out the tweeter and redo it, and then make crossovers.

Doing this would also be significantly cheaper. Dunno if that's an idea that's just a waste of time and money or what..

Nice try, sunrise.
If you do it is not for the price, is for the pleasure of it...

This is if you know the "makes" of the drivers. A lot of people can tell (brand & model) if they are not "printed". Usually is difficult because it can be a "similar".
To find another way of doing it, why not choosing a kit, or if you "go" with a certain price and brand you know in AU, starting from there.

[LineSource]

I've gotten my best results with a 12" coaxial. The coaxial configuration gives pinpoint coherence, and the 12" diameter woofer provides adequate bass for the limited center channel BW. Crossed LR4 at 1.3Khz. the beaming from the 12" woofer is beneficial in that it locks the voice to the screen.

You can purchase a true coaxial with a horn loaded compression driver, or DIY mount a tweeter just in front of your woofer. Some woofers have large phase plugs, and a small neo tweeter can be mounted to this.

If you are limited on height, look at 8" and 10" coaxial drivers.

[MJL21193]

Originally posted by sunrise3500
I'm looking at doing a DIY Centre speaker to replace my current MTM centre.

Thinking of heading down the W-MT-W path.

Centre channel is mainly for vocal content in surround setup, therefore I'd try to optimize for good midrange freq. response. There's not a lot of bass content to deal with. Keeping it simple will pay off.
Here's my centre - a pioneer 6 x 9 coax with my own crossover, in a sealed section of this entertainment unit. Serves me very well

PS: Oh, it's cheap too

[sunrise3500]

well ends up the woofers i was looking at on ebay are actually 6.5" midrange woofers
http://www.madisound.com/pdf/vifa/BC18SG49-08.pdf

these sound like they might be a good suit for a centre?
although if i've already got a pair 6.5" midrange, do i really then need another midrange? - falling back into just a MTM.... really wanted to go with something horizontal though, rather than vertically designed

it's just i've seen designs where people are using W-MT-W, and they seem to be impressed by the results...

[OzMikeH]

If you have an LCD tv you should be able to get away with non shielded speakers.
Might open up some options for you.

Not sure if magnetic field affects a plasma, I expect not but you should check. Go into a chain store with a small magnet and try it out on their TVs.

[sunrise3500]

yeah i dont care about shielded, since it'll be under an lcd

[sunrise3500]

1) so am I to take it that getting another set of the bookshelves and using the woofers along with a midrange and tweeter is stupid because I don't know the T/S parameters of the drivers...

2) what's the opinion of doing a W TM W setup anyways with other drivers?

3) With 2) for the W's would I want midrange woofers, or normal woofers?

4) are the alternatives suggested otherwise significantly superior? ie single coaxial + tweeter? (in all honestly i haven't even heard of the coaxials before, but I guess I can look into them)

thanks