[RJ]

I'd like to build two small subs (1 per ch) for my stereo system which consists of Harbeth Compact 7ES's and Primaluna Dialog 2 integrated amp. The plan is to use the subs as speaker stands for the Harbeths. I am looking for a very articulate sound that will extend down to mid 20Hz region and would like to stick with 8" to 10" drivers while keeping the driver cost below $200ea.

Please, are there any recommendations on drivers and/or designs?

Additional bit of info .... I plan on running the Harbeths full range and augmenting them with the subs. The subs will be powered through a Behringer DCX2496, setup as a low pass filter, and a 250 wpc ICE Powered Class D stero amp.

Thanks for the advice,
RJ

[pbrstreetgang]

nice idea! The gini stands would be out based on your LF requirements and the compact 7s might be too big. I sold my TBI subs(complete different design) to a 7es user and he is still thrilled. What ICE amps are you using?

[pbrstreetgang]

NM Analogue Research

[sbrtoy]

Scan-Speak 23W sub is incredible for small boxes with great extension and articulation though their cost is quite high.  At a much lower price point the Dayton 8" High Fidelity sub is a nice little driver you could use in a medium sized box.  I assume you are looking to stay sealed instead of vented? 

[RJ]

Sam,
Thanks for the recommendations. You are correct in that my preference is "sealed". I've been looking at the Scan-Speak 23W's and they ARE painfully expensive but I've found nothing else that compares.

RJ

[sbrtoy]

Besides the 23W there isn't much else that will get you deep response in a small sealed box without some EQ.  I am not familiar with your crossover unit, does it have any type of parametric eq?

[WGH]

The May '96 issue of Audio Magazine had an article about the HVCD (High Velocity Compression Driver) sub-woofer designed by Mathew Polk. I sent away for the free modeling package, but never got around to building the woofer. You can use this software for personal use only.

The woofer cabinet can be designed for either a ported or sealed cabinet.

Find out more by reading the pdf file:
PolkHVCD.pdf

The software spreadsheet for either Quattro Pro or Microsoft Excel can be downloaded here:
POLK-HVCD-SUB-WOOFER.zip

Wayne

[WGH]

The Marchand Bassis is parametric equalizer that will extend the bass response of a small box and is a DIY alternative to the Behringer.



The April 1990 Audio magazine has a detailed article about the construction, adjustment and use of the Bassis by Ralph E. Gonzalez.
Here is a copy of the article in a pdf file for anyone wanting to build one of these units:
http://www.wghwoodworking.com/audio/bassis.pdf

You can purchase bare boards and parts up to fully assembled units from Marchand.
http://www.marchandelec.com/wm8.html

Wayne

[Russell Dawkins]

RJ, I wouldn't be surprised if you got better results by biting the bullet and high passing the Harbeths. I believe the magic truly lies in the midrange and above for Harbeth and they manage what they do in the bass region by designing in a very carefully conceived bass hump which makes mating with a crossover difficult.

This could be ameliorated with a steepish roll off applied to the lower end of the pass band of the Harbeth.

I believe the benefits will out weigh the effects of the additional processing upstream of the Harbeth, but it will be easy enough to find out once you get the Behringer!

I think for sub mating, a sealed box main speaker is easier due to the roll off characteristics.