Woofer to use in a FAST with Alpair 5 (desktop system)

[Westy37]

As the title suggests, I'm looking to build a FAST (Fullrange Assisted Subwoofer Technology) system for my desktop. At the moment I've got the Alpair5s running fullrange in a crude open baffle and I'm pretty happy with their sound. However, they're desinged as a mid-tweeter and this shows. Bass content is muddy and actual low frequency response is pretty quiet relative to the rest of the spectrum.

So the plan is to build a passive FAST design crossed over from the Alpair 5 Grey | Markaudio somewhere in the region of 300-400hz. I don't currently have measurement equipment but it is on the way. So for now I am just trying to work out some candidates for the woofer to be used in this design.

A few restraints that are perhaps worth mentioning.

• I would like to use a 6.5" woofer due to space constraints.
• The combined volume for the alpair5 and the woofer per cabinet needs to be less than about 25 litres (again a space constraint). I intend to run the alpair sealed in a seperate chamber.

I would appreciate any input regarding potential woofers for this project. I'm not entirely sure what sort of efficiency I need to be looking at for the woofer and whether a 4 or 8 ohm nominal woofer will work most easily with the 4ohm nominal alpair driver.

One driver that I do have on hand is the Peerless 850122. If that is suitable I'll stop searching for a different woofer but if it's not then it's not a big deal; I'll find another use for it in another project. http://www.d-s-t.com.au/data/Peerless/850122.pdf

Other examples of FAST builds:
Nescio: Alpair5 + Trio8 + DSP = wow
A thread for Tysen and variations on FAST
Tysen Variation FE167E with CSS SDX7


So fire away, what woofers should I be considering?

[planet10]

I'd go ahead and use the Peerless.

I'm going to use a pair of push-push EL70s (in Thirlmere-R) as helper woofers with my A5 (in a 4" PVC TL). I'm using them because they are handy. The woofers will be oriented to the sides.

dave

[audiobomber]

A couple of plans to consider:

Alpair 10 + Alpair 5 Simple Plan | Markaudio

Alpair 5 / SDX7 Team | Markaudio

[Westy37]

Thanks for the suggestions. I should have added that I would prefer a subtle looking woofer i.e. not the SDX7.

Looking around a bit more I've seen this woofer:

Audiomarketplace - Exodus Anarchy 6.5" Mid Woofer

Exodus Anarchy tested by Zaph - Techtalk Speaker Building, Audio, Video, and Electronics Customer Discussion Forum From Parts-Express.com

Anyone have an opinion on this one? To me it seems very similar to the SDX7 but minus the flashy looking phase plug.

[Westy37]

I also meant to ask; what sort of volume should I be looking at for the sealed box of the Alpair5?

[audiobomber]

Originally Posted by Westy37

I also meant to ask; what sort of volume should I be looking at for the sealed box of the Alpair5?

If you cross high enough, sealed volume doesn't matter too much. One of the reasons I thought to post the kits was to give you some ideas in case you want to go your own way. For example, you would be safe to use the same volume as Markaudio.