Bookshelf Speakers for Computer and HT use.

I am currently designing my new audio system for my computer / home theatre system and I have a bit a of problem.

I plan to use stereo subs and bookshelf speakers for the rest of the audio spectrum.

For the bookshelf speakers, I would like to use Audax AP100Z0 woofers with Morel MDS-30 or Morel MDS-32s tweeters in an MTM config. Any comments on this combination? are these good drivers? have any of you heard them in action or used them?

the maximum external dimension for the bookshelf speakers are (WxHxD) 130mm(5.11inches) x 400mm(16inches) x 450mm(18inches) so i could use 18mm (just a tiny bit under 3/4 inch) MDF with just enough room left to squeaze all the drivers in ..... is this ok or should i drop back to 1/2 inch MDF?

I dont have any speaker modelling software .... what can i use that is free? how low could i expect the bass from these speakers to go at -3dB in a sealed enclosure of this size? how much damping material should i use to get the best frequency response?

Does anyone know where i might be able to source magnetically screened supertweeters? i didnt know they even existed (screened) until i found the Komri at if i can find some, i will use a MTSTM config.

Any advise you could give would be greatly apreciated.



[Edited by AudioFreak on 11-10-2001 at 09:32 PM]
WinISD is nice, because it's free.

WinISD is available at no charge from

I like it because I can sit all day trying new combinations and imagining listening to the finished product. My "American Thunder" subwoofer is designed by WinISD. I can virtually "build" the speakers on paper and make sure everything fits together properly. WinISD is my friend because I don't have a lot of money and it's free. It has never steered me wrong, but I hear bad things about how speaker programs in general model bandpass subwoofers.
The best I can tell you...

Shop around. I was going to build my "American Thunder" subwoofer using a Dayton Titanic 10" until I found the Blueprint 1001. I got it today and it looks like a mini 1203 or even a mini Stryke/TC HE15, only with a poly cone and a rubber surround. I'm very pleased.

If you must have famous-maker drivers, try Vifa, Scan-Speak, Focal, and Hi-Vi. All of these can be found at, the cheapest place (in my experience) to find any of these big-name drivers. Or, you could use the Stryke 7" woven glass fibre midbass and the Stryke ribbon tweeter, or the Stryke soft dome.

Or, if you must have Morel drivers, or if you must have a ported box, put the port on the back to hide it from view. I don't know why you wouldn't want a ported box, though. I like bass ports.
My DIY computer speakers are AP100Z0 (sealed) with TW025F1 tweeters. Filter is first order on the woofer and second order linkwitz on the tweeter. Speaker size is 24 x 14 x 16cm, 16mm MDF:


The sub is a AP210G6 in 26liters (ported). I plan a center channel (because I upgraded my sblive! to a sblive!5.1) with the same drivers.

The sound: very pleaseant, the tweeter is sligtly better off-center (don't forget that it is for computer use, so very close listening).

Joe d'Appolito has made a kit for Audax, a MTM configuration with AP170Z0 and TW025F1. I don't know if it is always published on audax site, you can find it at (french electronic retailer), but in french.
Leazy way...

AudioFreak said:
martinc what crossover point do you use between the computer speakers and the sub?

No crossover, I use a custom made amp with active filters. Second order for the sub, first for the mid/tweet, because of the natural roll-off (it starts about 100Hz). I had a lot of problems to made them work together, the best compromise was to cut sub about 120Hz, and sattelites little bit lower.
IMHO 75Hz is too low for 10cm drivers, even if you reach it, power handling and distortion will be a major problem. Go for 120/150Hz, or use 13/17cm drivers.

I've spent the last 2 days trying to work out what i can do to solve this problem.......

I am going to use a Linkwitz transform circuit to get the frequency response that I require from the bookshelf speakers and because i am using a MTM config, i should be able to get just over 105dB nominal (at 0.5m remember these are for a computer) +/-3dB 80Hz-20kHz which should be enough i think.....

Now I am left looking for a suitable tweeter...... any ideas?

martinc what frequency do you cross over between the woofers and the tweeters ..... i just looked at the frequency response graph for the AP100Z0 and it looks nice between 100Hz and 1kHz but it aint so nice above 1kHz.

With the Linkwitz transform circuit, the woofer efficiency is down about 6dB each..........

[Edited by AudioFreak on 11-22-2001 at 11:09 PM]