[sts9fan]

I just got a pair of Mark Audio A7.3 and was thinking of using them with a helper woofer. I will still use my subs for the deep stuff. I was thinking of a two module system with both being sealed. Use the A7 from somewhere around 180hz - 300hz  up and the woofer and subs below that. I guess I would want a 7" or 8" woofer. What do people think of this idea?  Any suggestions on woofers that would be <$200 /pr?
Kris

[Poultrygeist]

I built a pair of simple H Frame open baffles using the inexpensive 15 inch Eminence Alphas and couldn't ask for better bass support.


 

[sts9fan]

Can you post your H-frame dimensions?  Where is your xover point?

[Poultrygeist]

16 inches high, 16 inches wide and 7.5 inches for cavity depth each side. I used 3/4 plywood.

I'm using two Dayton amps with built in crossovers which I set at 80hz. You can drive the Alphas with just one amp. The Alphas give very natural and  musical bass and go low enough that a sub IMO is not neceassary.



http://www.quarter-wave.com/OBs/U_and_H_Frames.pdf

[sts9fan]

I finally started this project.  I put the Alpair 7.3 in a sealed Parts Express 0.25ft^3 box. these things sound sweet!!  I am going to be using a ported 6.5" for the helper.  I really do love these PE boxes!!  More to follow.

[chrisby]

The PE boxes are certainly a quick solution for non builders, but if you're up to a a simple DIY box for the Alpair7.3 - try the Pensil - slot vented MLTL. 

[chip]

Did you line/stuff the boxes with anything?

[chrisby]

Did you line/stuff the boxes with anything?

if you're referring to the Pensil,  yes - as described on drawing, approx 13 oz (355 grams of your favorite fiber fill - Acousti-stuff , etc)

http://homepage.mac.com/tlinespeakers/FAL/downloads/pensils/Pensil7s3-map.pdf


as these types are fairly skinny for drivers this size, it's wise to make cabinets with at least portion of one long panel removable to allow access for initial installation and subsequent adjustment of fill - I build with full length of back panel removable on cleats, and seal with closed cell foam tape

some cross bracing doesn't hurt either




 

[sts9fan]

This is my third speaker with a Mark Audio driver.  I have built a pensil for the chr70 and a Woden Dunideer. These sound way better.  I may one day try the Pensil for them.  I stuck some vinyl floor tiles and sonic barrier inside the PE boxes.
Also, for this project I don't need the TL bass. The Alpair will be crossed at 200-300hz.

[chrisby]

This is my third speaker with a Mark Audio driver.  I have built a pensil for the chr70 and a Woden Dunideer. These sound way better.  I may one day try the Pensil for them.  I stuck some vinyl floor tiles and sonic barrier inside the PE boxes.
Also, for this project I don't need the TL bass. The Alpair will be crossed at 200-300hz.

In which case even a little 6-8 liter box like the PE could be all you need - as an inveterate DIY hack, I just can't help suggesting that approach - but I think you knew that already 

yes, the Alpair7.3  is a substantially better driver in all regards than the CHR70, in any box


are those Geddes Nathans?

[chrisby]

but to actually address your initial question re helper woofers - I quite like the CSS SDX7, but for far less money something like little 6-8" Peerless, or  SilverFlutes are very nice  - and I've found that dual cheaper Push/push drivers per side can offer advantages over singles of larger size/higher cost.

 

[sts9fan]

Yup those are Nathans. Tough for a single driver to go against.

I like the push pull idea.
 Also putting something small into that box could be a super cool speaker!
Right now I am putting Exodus Anarchy 6.5" mid woofers in a 0.5ft^3 vented box. The box will be tuned to 40hz for hopefully a high 30s F3.

[planet10]

I like the push pull idea.

Chris said push-push. Push-pull lowers 2nd order, does nothing or increases 3rd order -- good on the numbers sheet, less so to your ears.

Althou quick & convienient, the rectangular PE boxes are a quality step behind the PE curved ones, which are OK. You can get more out of the A7.3 with a stiffer enclosure with a lower diffraction signature. So if you get the itch to see how much more there is, there is another project for you

7 litre sealed is spot on for use as a mid-tweeter.

dave

[sts9fan]

You may be correct on the cabs but that was out of scope.
I am a mediocre woodworker and painfully slow. This project is mostly to play with a miniDSP and not an attempt to squeeze everything out of the A7. I was actually gonna use a tweeter  but i remembered i had bought these.  That said I am impressed and may put some in a vented box. I guess the frugals would be fun.
I am a bit dubious that the curved PE boxes are that much better in a modern living room environment. 

[planet10]

I am a bit dubious that the curved PE boxes are that much better in a modern living room environment.

They are. The rectangular ones need a lot of work (added bracing) to not kill the sonics.

dave

[sts9fan]

As I said you may be right. I do think "kill sonics" is a bit dramatic.  Have you seen how well the Nathan kits were braced?

[planet10]

As I said you may be right. I do think "kill sonics" is a bit dramatic.  Have you seen how well the Nathan kits were braced?

I understand that many people brace them more adequately than Geddes does. I have had a number of "conversations" with Geddes about his bracing. He does not have an open mind. There are a number of other things we disagree on.

dave

[sts9fan]

My point is that I have not taken an extreme course either way. I would also say the sonics are not dead.

[BPoletti]

Have you considered a Peerless 830668?  Nice driver.  Used in a sealed box of around 90 litres, it works very well and goes plenty deep with in-room response below 30hz (depending on placement and seating position).

[sts9fan]

I changed which driver I was going to use a lot. I ended going with the Anarchy  because I had two in some tapped horns I did not mind trashing.