Design questions using the Tang Band W5-704D

[lostboy77]

I'm looking to build some desktop/computer speakers using a pair of Tang Band W5-704D in a 2.5 TMM design. The Tweeters and (TM) XOs I already have (taken from a car audio setup from MB Quart). XOs are basic 2nd order at 5200Hz with Tweeter L-Pad adjustments for 0dB, -3dB, and -6dB. Judging from what I've read (mostly from this site) the W5-704D should be able to handle being crossed this high and the adjustable L-Pad should allow for proper pairing with two of the W5-704D wired in parallel for a 4ohm load.

Correct me if I'm wrong, but I'm thinking that the ".5" of the 2.5 setup could be used for BSC rather than applying this in the XO.

My questions are twofold. First, What size enclosure/port should I shoot for (I have plenty of .75" MDF and I'm not scared of largish desktop speakers) and how should I cross the second woofer to allow for proper BSC. I am NOT planning on using these with a sub.

BTY, I'm planning on purchasing the woofers and trying this out. If I can't make it work with the stuff I have, I will simply purchase the remaining components for a more "proven" design. This will be powered by a Pioneer Elite A-35r which rated at 65watts to a 4ohm load.

[Ryan_M]

Re: Design questions using the Tang Band W5-704D

sorry to burst your bubble but I don't think this project is going to work out. You can't us an off the shelf XO with some random design and expect good results... and 5.2kHz is way to high.

Also a 2.5way with drivers like these isn't going to be a desktop system. Just doing a quick model - since you don't want a sub - I ported them and you're going to want ~40L. So a box that is 8" wide and 12" deep is going to have to be about 42" tall.

Yes the .5 of a 2.5way is specifically used for BSC.

[jclin4]

Re: Design questions using the Tang Band W5-704D

To confirm what Ryan has modeled check out my Project A link in my signature below. W5-704D want lots of internal volume, in my case I ended up with 44 liters.

You are going to need a crossover specifically designed for this midwoofer and your tweeter. That said, the W5-704D is a fine driver at a very good price.

[Wolf]

Re: Design questions using the Tang Band W5-704D

15 ltrs is enough for the W5-704D.

http://s18.photobucket.com/albums/b117/wolf_teeth_speaker/Canvas/

Writeup is in my blog linked below.

FWIW- I agree with Ryan about your tentative setup.
Later,
Wolf

[DanP]

Re: Design questions using the Tang Band W5-704D

Not to pile on, but you generally don't need any BSC in a desktop/computer speaker design as they're usually listened to nearfield and sit close to the wall/desk. The W5-704 is pretty well behaved and actually might sound OK run full-range with the tweeter you have crossed at 5.2kHz. If you build the speakers angled back to face you and you listen nearfield, the high crossover point and large CTC distance shouldn't be too much of a problem. I would try a TM with the tweeter and crossover you already have and try the woofer with and without the lowpass circuit.

Dan

[critofur]

Re: Design questions using the Tang Band W5-704D

sorry to burst your bubble but I don't think this project is going to work out. You can't us an off the shelf XO with some random design and expect good results... and 5.2kHz is way to high.

One person I know who uses tools such as 3d laser vibrometers to analyze driver breakup modes and correct them (through driver modifications or design changes) would say 5.2Khz is to low and the W5-704D can easily crossover higher, and sound better than more typical designs that crossover around ~ 2 - 3 Khz...

EDIT: Oh, and probably one W5-704D would yeild far better results than even most "high end" PC speakers - should be able to play nice and loud nearfield.

[lostboy77]

Re: Design questions using the Tang Band W5-704D

I would try a TM with the tweeter and crossover you already have and try the woofer with and without the lowpass circuit.

Dan

Due to the natural roll-off of the W5-704 this does sound like a fairly good idea. Thanks . . . I never would have thought of it. Your absolutely right about making sure the driver is facing me while crossed this high. I can only imagine how bad the off access response this thing will have when crossed that high. I think that these will need a large enough enclosure that I shouldn't have too much of an issue placing the driver at ear level so angeling them up won't be much of an issue . . . driver to driver spacing may be an issue though.

To all the nay-sayers . . . I understand that there is a great deal of risk in trying something like this and that with even the best of luck, the final results will still not be ideal. I'm trying this more as an experiment in what can be done with what I have. If it does not work out, nothing is lost as the drivers are not that expensive and usable in some "proven" designs that I would really like to build anyway.

From the other side. I certainly understand and appreciate the warnings. This is a very easy hobby to make assumptions in. Both positive and negative feedback is always appreciated.