Cheap-O Center Build

[Adam_G]

Alright, before I get hounded for being an idiot, I'll preface with this: College budget (aka none), terrible room dynamics, new to speaker stuff in general.

Goal: Use the two Tang Band 3" drivers ( http://www.parts-express.com/pe/show...number=299-113 )(leftoversfrom a repair) to build a cheap center channel.

Basic info:
Speaker Info:

Name: W3-881SI 3"
Type: Standard woofer
Company: TB Speakers
No. of Drivers = 1
Fs = 106 Hz
Qms = 7.17
Vas = 0.05 liters
Xmax = 0.5 mm
Sd = 69 sq.cm
Qes = 0.96
Re = 6.6 ohms
Le = 0.212 mH
Z = 8 ohms
Pe = 30 watts

Dimensions:

Realistically, anything is better than what I'm using as a CC right now, which is an old satellite speaker from a surround system.

I have basic electronics knowledge if I need to add any kind of simple x-over, but I don't know if it will be necessary, I'll leave it up to you guys.

If anyone can help me decide dimensions/layout/anything really that would be great. It really doesn't have to be perfect sound-wise, just something for me to play with to put these two drivers into use and off of my desk.

[Adam_G]

Re: Cheap-O Center Build

How would I calculate the best center-to-center measurements for these two speakers? Or should I just mount them as close together as possible?

[johnnyrichards]

Re: Cheap-O Center Build

Well... with the addition of a single 4 or 5 uf capacitor, you can make kind of an "inverted" 1.5 way speaker. Place them (ideally) in a vertical array, but horizontal is ok too if you get them very close.

[Adam_G]

Re: Cheap-O Center Build

@Johnny:
What would the advantage be to the 1.5 be? I'm not really sure what that is or what it would do for the sound. I can put them vertically given where they are going if it would be better. I know a little about comb filtering so I assumed that vertically would be better, but confirmation is always good.

[dcgold2000]

Re: Cheap-O Center Build

Johnny is absolutely correct and the inverted 1.5 is an interesting concept.

[patrickm]

Re: Cheap-O Center Build

i'd be interested to hear how the inverted 1.5-way concept works out.... but while you're adding parts to your cart, you might want to consider the nuance mylar -073 3" waveguide tweeter. johnny and i have both used versions of it (he used the larger waveguide) and were happy with it for the $2.50 price. one cap, probably one resistor, and one inductor and you could go the MTM route for not much money.

[johnnyrichards]

Re: Cheap-O Center Build

Adam, I cleared my PM box out, so go ahead and resend! Or better yet, use my email.

[Adam_G]

Re: Cheap-O Center Build

I figured you guys would like to see my work so far.... hahaha.

For what it's worth(which is nothing): It sounds better than what I'm using as a CC already, which really scares me.



@Johnny: I tossed you a PM about the 1.5 idea, just some clarification stuff.
@Patrick: I definitely wouldn't mind the MTM idea, but I will need some guidance on that if I do end up going that way. I'll definitely let you know.
Thank you both for your help by the way. : )

[donradick]

Re: Cheap-O Center Build

Dude, I dig your cardboard box work. I've run speakers like that for weeks and months sometimes. I'm going to go out a limb here, and suggest you just run them full range with no crossover for your center channel. If you are running them from a HTR, set them as "small". If you can choose a high pass of 100HZ, perfect, but 80Hz would probably work also. Listen to them for a few weeks, and figure out later if you really need a tweeter and crossover.

What kind of woodworking tools do you have? If not, you can get some small boxes from PE or Ikea, but you will still need some glue, a drill, and jigsaw.

[John_Frum]

Re: Cheap-O Center Build

I agree with my fellow ATLien. My nephew has a set just like this and they sound amazing with not filters. Are they perfect? Nope but they sound really really good. They don't need a tweeter at all. The 1.5 way thing does sound interesting and I think my nephew is playing with that idea now. One thing those speakers do REALLY well is the human voice. Considering that's the main function of a CC, I think you made a good choice.

http://www.youtube.com/watch?v=8KEvSBZvA-c

http://www.youtube.com/watch?v=BXPr986ldoM

[Adam_G]

Re: Cheap-O Center Build

@donradick: Haha, thanks. I'm an engineering student, which means I have to be a master cardboard craftsman from all of the stupid cardboard bridge / tower / everything projects. Right now I'm running them as small on my HT system, but it's old and a piece of junk, so I can't adjust the x-over on it. The only time I really use my CC is when I'm listening to music very quietly and for movies, so it's doing well in both of those areas as it is. For loud music I just listen in stereo. As far as the woodworking goodies, I have to wait a few weeks to head back home and grab them, or make my boxes there. I've got pretty much everything you can imagine, and I believe I actually have some very nice cherry I could play with hiding out in my garage. We will see how that goes.

@John: Your nephew's setup is pretty nice. It's funny, the dimensions are almost exactly the same as my cardboard box from what I can tell! Lucky pick from the trash pile. I agree that they don't really need a tweeter, since they are reasonably smooth from ~300-15k. Right now in the cardboard box they're responding better from like 1k-10k, but I think when they are properly fastened to a baffle that response will expand to what it should be. I've been looking around and seen people tuning them down below 100hz, but I don't need that since I have a subwoofer in my system.

For anyone: Noob question- What is a 1.5 speaker, and what is the advantage of a 1.5 speaker over whatever you would call my cardboard box speaker?

[donradick]

Re: Cheap-O Center Build

@donradick: Haha, thanks. I'm an engineering student, which means I have to be a master cardboard craftsman from all of the stupid cardboard bridge / tower / everything projects. Right now I'm running them as small on my HT system,
For anyone: Noob question- What is a 1.5 speaker, and what is the advantage of a 1.5 speaker over whatever you would call my cardboard box speaker?

So, what kind of engineering student are you?

A 1.5 system means 2 woofer-mids run full range, but with a coil on one woofer that acts as a low pass filter and rolls if off. So you have 2 woofers running on the bottom, but only 1 driver for high mids and highs. This means you don't get "lobing". It's all detailed in the big "speaker building bible" thread above.

[Adam_G]

Re: Cheap-O Center Build

So lobing and Comb Filtering are essentially brothers-from-another-speaker. I see how the 1.5 would help now. Since the speakers aren't horizontally arranged I haven't run into any problems with it so far, which is nice.

I'm Industrial Engr, but I've had alot of Mechanical experience and some training in circuits and electronic concepts.

[donradick]

Re: Cheap-O Center Build

So lobing and Comb Filtering are essentially brothers-from-another-speaker. I see how the 1.5 would help now. Since the speakers aren't horizontally arranged I haven't run into any problems with it so far, which is nice.

I'm Industrial Engr, but I've had alot of Mechanical experience and some training in circuits and electronic concepts.

re: lobing - BINGO - constructive and destructive interference when the wavelengths get short enough. That's why you never see 2 tweeters on a well-designed speaker.