Bass enclosure building question?

[Doug Kim]

Hello all

I have a pair of Fostex H420 horns so I am going to build a 2 or 3 way system something similar to this.

Fostex H400 horn system

I will use Fostex recommended parts, but the problem is to build bass enclosures.
I do not have any idea what should be the design, and I do not know how to build either.

Can anyone give me some ideas on a good 15" woofer cabinet that similar to the above link, and any good woodworker in Maryland?

And what do you think if I use Madisound's BK-20 horn as bass unit along with H400/H420 horn crossed at 1kHz?

Thanks

Doug

 

[Inductor]

Hello Kim,
Do you live close to Balmor. I worked for RTKL. Where the Clippers, the fastest ship in the world, were made (and are repaired). Lot's of good wood and visionary workmanship.

 

[GM]

Greets!

Well, apparently Fostex has 'upgraded' the FW405 to the FW405N along with a new price-tag that borders on the ridiculous as well as a big step in the wrong direction SQ wise, but in theory would still be a wise choice: http://madisound.secureserverdot.com/catalog/product_info.php?manufacturers_id=131&products_id=8207

A much better choice would be either dual W300IIs or the W400II since the specs/FR response more closely mirrors the FW405's, but apparently you'd have to order either from Japan, so probably even more ridiculously priced: http://www.fostexinternational.com/docs/speaker_comp/W-Series.shtml

Recommended cabs:

http://www.fostexinternational.com/docs/speaker_comp/pdf/recom_enclose/w300aII_encl.pdf
http://www.fostexinternational.com/docs/speaker_comp/pdf/recom_enclose/w400aII_encl.pdf

WRT BLH cabs, to get a decent power response match between the horn and woofer at ~1 kHz XO point either dual horizontally opposed 12" or single 15" is typically required, so ideally you'd want to do a custom design since prosound 'scoop' bins tend to have huge 3rd harmonic dips along with too high a cut-off for HIFI if no sub system is used.

Having been down this 'road' decades ago experimenting with both FH and BL horns I finally concluded that dual 15" in either sealed, ~max flat vent impedance or large EBS alignments have the best trade-offs overall in a HIFI/HT app depending on personal preference, room space available and whether or not a sub system is used.

Lately though, OBs have been the 'Hot Ticket' now that high linear excursion drivers and relatively inexpensive digital EQ is available, so another option that some argue is the only alignment worth considering. Up to a point I tend to agree from both a sonic and technical POV since a driver wants to 'feel' a matching acoustic load on both sides of its diaphragm, though IMO a high SQ sub system is de riguer below ~60-80 Hz depending on the room. Unfortunately, for an all Fostex solution it will require multiple drivers/channel AFAIK to get linear efficiency up high enough to go this low if not backed into a corner, ~defeating the point of OB.

GM