Building the center channel

**the_diyr** · **09-29-09, 11:12 AM**

Ok here is where I am .. I have 2 - 4 ohm speakers I am going to wir in Series .. to get 8 ohms .. Now I am stuck with what and how to use a tweet.. see the pic..

**the_diyr** · **09-29-09, 11:17 AM**

I had 2 little tweeters where the holes are open .. but had to remove them , I thought about maybe just getting a 3x7 horn to go in the center .. I am not sure,, I could just get a pair of auto tweets that do not need a crossover and run them in series I think .. Anyway the whole front is going to be covered by a black cloth screen so being ugly will not matter much..

**JCD** · **09-29-09, 01:29 PM**

A few comments questions...

Is this going to be a home speaker? Or for your car?
Was this a design you came up with?
Why are you using two tweeters? I have nothing to back this up than what I heard from someone a lot better at this stuff than I is that two tweets act REALLY strange. More than two could be OK, but two is bad.
Are you going to mount those drivers as they are right now? or will you slide the driver through the hole so that the flange is on the outside?

**the_diyr** · **09-29-09, 03:18 PM**

I am going with one tweeter .. Those two holes were a mistake.. I am looking at putting in a 3x7 horn. .. This is going to be a test prototype for my home center channel.. If I can get it to sound good like I want I will be using new wood, new pipe , make the holes with holesaws ..This is a basic test speaker.. I have also been toying with the Idea of taking some good 5.25 or 6.5 inch 3 way car speakers , put two of them in a box and hook them in series to get 8 ohms just to see what they will sound like.. I remember years ago I had two homemade speakers that I put two 6x9's coax speakers per box .. They were hooked in series to get 8 ohms per box and they sounded great >>>

**the_diyr** · **09-29-09, 03:49 PM**

By the way how would 2 - 6.5 inch woofers sound in a .55 cubic foot enclosure.. Just Curious . as I need my center channel box to be no bigger than 7" tall , 24" wide, and roughly 8 Inches deep.

**JCD** · **09-29-09, 04:32 PM**

So some random responses...

Good on the single tweeter
A horn tweet might be a little much --- horns are usually VERY sensitive and might be overkill for this application. I've also heard that there are sometimes issues with implementing a horn design. I don't know what they are, just that I've heard that. Given all that, I'd go for a soft dome or metal domed tweeter.
I'd stay away from auto speakers if I could. They're designed to work in an small enclosed area rather than an open area. Generally speaking, they don't work as well in a HT setup.
I think 6.5" drivers would generally be a good for a center channel like this -- however, it's always driver specific. The reason why I think it might be good is that generally larger drivers go deeper, and since you won't have a full blown woofer, bigger is generally better. That being said, some smaller drivers will outperform bigger drivers. It just depends on the driver.
The proper size of an enclosure is completely dependent on the T/S parameters of the drivers you're going to be putting in the box. The only way to know if .55 cu ft is the proper volume is to plug the data in one of the handful of speaker designing programs out there on the net. WinISD is just one of a half dozen I know of.
Remember that when you try to calculate the load of a speaker, you don't need consider how the tweeter is wired to the woofers/mids -- the electrical signal is going to be going to either the woofers or the tweeter. In other words, 2 4ohm woofers in series make an 8 ohm load. Adding a 6 ohm tweeter doesn't get included in that calculation. You probably already had that one, but I had a brain skip on that issue once..

**the_diyr** · **09-29-09, 07:14 PM**

Thanks JCD ... I am going to keep playing with the design.. Your right on the horn tweet .. It's a little much on harsh sounding side.. I wish I could afford a pre built center channel but for you could buy for 200 or 300 I could probably buil for about 50.00,,, I also found project wood boxes at Hobby lobby for about 10 to 20 bucks they are made of 1/2 inch solid wood .. they come in a bunch of sizes .. I found one that was 22 inches wide x 8 inches tall and 6 inches deep for about 19.00 .. It is cheaper than I could build it..

**brianpowers27** · **09-30-09, 10:27 AM**

Don't forget to stuff those woofer tubes. Tubes are less than optimal, from a resonance point of view.

**the_diyr** · **09-30-09, 11:21 AM**

I am thinking polyfil for the tubes or maybe expanding foam... I also figured the crossover network for my 3 way st-828 fisher speakers today ... see pic... Now I am working on a crossover for the center channel ... Here is the one for the front floor 3 ways .....

**the_diyr** · **09-30-09, 11:40 AM**

I am thinking for the center , not really using a crossover .. just 2 - 4 ohm speakers in series with a pezio tweeter ... if i use a soft dome tweeter I may put a 1.99uf cap in series ... .. The speakers will probably be 5.25 inch or maybe 6 inch not sure yet .. I may decide to run 4- 8ohm speakers in series/parrell.. with a soft dome tweet and a 2.10 uf cap .. Just cant decide >>><<<

**brianpowers27** · **10-01-09, 09:48 AM**

Quote:

the_diyr wrote:

I am thinking for the center , not really using a crossover .. just 2 - 4 ohm speakers in series with a pezio tweeter ... if i use a soft dome tweeter I may put a 1.99uf cap in series ... .. The speakers will probably be 5.25 inch or maybe 6 inch not sure yet .. I may decide to run 4- 8ohm speakers in series/parrell.. with a soft dome tweet and a 2.10 uf cap .. Just cant decide >>><<<

I tested several buyout Piezos last week. They don't look real promising, without a xo.

If you get the chance... There is a fantastic intro to speaker building called "Ray Alden's Speaker Building 201" This site also helps. http://undefinition.googlepages.com/diy-gettingstarted

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