Contour Enthusiasts Group Archives Forums Modifications Audio Attn: Dave - Gotta OT HT Question

Dave, I'm planning on rebuilding some Radio Shack speakers with some new drivers. They'll be part of my budget HT system using a Dayton DVC/PE Plate amp. I haven't designed a center channel yet, and I was thinking of using this TB Driver ( link ) in a "1-way" speaker for the surround channels.

I'll be using a Tang Band 4" driver ( link ) and a Dayton Mylar Tweeter ( link ) for the Radio Shack speakers rebuild.

The enclosure is .06ft^3 and I'm nearly stuck with those drivers due to the cutouts and size of the speaker's face. Do you see any problems with using these drivers? I couldn't find much info on the mylar tweet.

Any advice on what type of x-over to design? I'm thinking of a crossover frequency at approximately 5KHz. I'm guessing a 2nd order... Does a 2nd order crossover flip the polarity on both the tweet and woofer?

Thanks for any insights.
-Colin

my advise is to replace the tweeters with the 88 cent specials. They have excellent response from 6khz up to 20 khz and will save you some money. Not to mention, they are tiny. (i believe they are made by audax, which will explain their good performance). With them, I would probably do a 6-8khz crossover point. I will get back with on the slope and crossover type.

Alright, I'll give the 88cent tweeters a try. Maybe I'll just get 5 sets of the same woofers/tweets and build a whole matched system.

I would recommend it. The crossover component should be cheap enough. you will need some sort of notch filter on the tweet to calm the peak at 4khz, but once you do that, they perform admirably. Just remove the phase shield.

I have a fun new crossover calculator that takes VC offset into account. I will play around with options for you and see if I can find the best fit.

Hello Colin,

So far, assuming they are on the same baffle with no driver offset, I would go with a 2nd order butterworth crossover at 5500hz on the tweeter and a 3rd order butterworth at 3600hz on the mid. It will result in a mild .2 dB ripple at 3600khz and with a mild .4 dB trough, roughly 1 octave on either side of that point.

I would also recommend notching out the peak at 4000khz between the crossover and the tweeter.

Thanks for the info Dave! I think I can figure out how to build the crossovers (my first time) using a site I found which has calculators and diagrams, but I don't understand how a notch filter works. Any links or info on how to do them?

-C

If you have Excel 2000 or newer, there are some very useful tools here http://www.pvconsultants.com/audio/frdgroup.htm

The crossover calculator is quite nice, but doesn't take VC offset into play. It should allow you to model the different hi and low pass filters with relative ease and has a Notch filter calculator and diagrams for everything.