Going to build a BIB - please help with driver selection - Fostex FE138ES-R ?

[okayfine]

Madisound has the Fostex FE138ES-R on sale right now for $289.

Would this be a suitable choice for a BIB ? It is right at the upper limit of my budget for a driver.

As far as the actual build goes, my plywod supplier has a 7-ply cherry plywood. The veneer cores are american birch. Some voids but very few. Is this no good? Should I got with 11 ply baltic birch and put a veneer on it?

How about if I build it with 6/4 solid mahagony with dovetail joints? Would it have weird resonances if made of solid wood?

Thanks in advance for your replies.

[Scottmoose]

It will work fine. Pretty much any driver can be used -it's just a question of cabinet size.

Void free. Voids are bad. That's one of the reasons BB is prefered. Some solid woods are fine, if the material has been seasoned etc correctly, you know what you're doing, and it's not going to be subjected to major temperature / humidity variations.

[Godzilla]

What Scott said above.

The 138es is a special and rare driver. It will make great sounding speakers! Put them into BIBs, put them into corners and enjoy.

They can also be used successfully in other cabinets. I believe they are a 'sound' investment.

Peace,
Godzilla

[chrisb]

Originally posted by okayfine


As far as the actual build goes, my plywod supplier has a 7-ply cherry plywood. The veneer cores are american birch. Some voids but very few. Is this no good? Should I got with 11 ply baltic birch and put a veneer on it?

11 ply would make that 5/8" (15mm), which might be a bit thin for a BIB - 3/4" (18mm) would be a better bet, but as BB is sold in many jurisdictions in 5x5ft sheets (1524mm), you might need to get creative with your joinery (biscuits, lap joints, etc).

If you plan on a nice finish veneer, you could certain hide it with a wood on wood 2 ply veneer.

When it comes to loudspeaker cabinets, IMHO it's the high ply count that give BB or similar plywoods ( Appleply, etc) their major advantage over MDF/chipboard or even low ply count plywoods, and a driver of this caliber certainly deserves the extra effort.

How about if I build it with 6/4 solid mahagony with dovetail joints? Would it have weird resonances if made of solid wood?

Thanks in advance for your replies.

As Scott said, providing you have a good handle on working with solid woods, there's no overwhelming reason why not - although 6/4 could be a bit overkill in terms of thickness.

[serenechaos]

Do you just not like the designs supplied w/ the 138 driver?
Or already tried them?

(I've just never heard a bib impressed, pretty disappointing compared to the swans & nessies i've heard, but ymmv...)

i ask because i've tried a few cabs for the 138, plan to try the resonate pipe next (in spruce), just haven't heard but one other person who built it (a very experienced builder, who did like it).

or maybe try one of these:
http://www.geocities.com/sg_suzuki/MCAP-CR.html
http://www.geocities.com/sg_suzuki/F...x_Project.html

r

[okayfine]

Originally posted by chrisb


11 ply would make that 5/8" (15mm), which might be a bit thin for a BIB - 3/4" (18mm) would be a better bet, but as BB is sold in many jurisdictions in 5x5ft sheets (1524mm), you might need to get creative with your joinery (biscuits, lap joints, etc).

If you plan on a nice finish veneer, you could certain hide it with a wood on wood 2 ply veneer.

When it comes to loudspeaker cabinets, IMHO it's the high ply count that give BB or similar plywoods ( Appleply, etc) their major advantage over MDF/chipboard or even low ply count plywoods, and a driver of this caliber certainly deserves the extra effort.



As Scott said, providing you have a good handle on working with solid woods, there's no overwhelming reason why not - although 6/4 could be a bit overkill in terms of thickness.

Correction - the BB i have must be 13 ply then. It is 18 or 19mm. It is 5x5 sheets, but I do have access to 4x8 sheets.

My main concern using solid wood is the seasonal expansion/contractions. For small bookshelf or even regular floor standing applications, the wood movement is not terrible, but for a long BIB, it might lead to splitting.

Has anyone built or listened to a BIB using Jordan JX92S drivers? (I did do a search).

Thanks.

[mp9]

Originally posted by serenechaos
(I've just never heard a bib impressed, pretty disappointing compared to the swans & nessies i've heard, but ymmv...)

i ask because i've tried a few cabs for the 138, plan to try the resonate pipe next (in spruce), just haven't heard but one other person who built it (a very experienced builder, who did like it).

or maybe try one of these:
http://www.geocities.com/sg_suzuki/MCAP-CR.html
http://www.geocities.com/sg_suzuki/F...x_Project.html

r

hi robert, been wondering what you've been up to. so a Multiple-Chamber Aligned in Parallel Cavity Resonator (MCAP-CR), don't know where you found it but looks interesting. keep us posted on the build (you may as well get on with it, (lol)). it's different and jack k. already did the nessie and didn't seem as enamored with them as he was with the exotic's unfiltered in a simple sealed box. he said something wrt the exotic/sealed enclosure having more bass output than a 138es-r/nessie. any idea how the mcap-cr concept is being accepted by other builders and by those who've been able to hear them?

[serenechaos]

hi mp9,
i saw the MCAP-CR in the feastrex thread; thought it looked interesting.
i talked to Kloss about different cabs for the 138; he said he liked the nessies. he also used a lcy for the top.
wasn't the exotic in a three-way?
(doesn't any "full-range" seem to end up being a three-way if you actually want to go the full range).

what i've been up to...
haven't done anything else w/ the 138s, they're still in the bvrs, collecting dust, waiting for the spruce to dry some more, & me to get enough time to mess w/ them.
did finish a pair of tapped horns, but still need to finish the middle three of the five-way front-loaded horns i'm building.
& finish a 76 > 304TL transmitter tube amp.
& build some lowther field-coil conversions.
then build field-coil compression drivers for the flhs...
then build a smaller four-way flh second system.
then the wood should be dry enough to build a nessie.
yeah, enough to stay busy...

[mp9]

wow that's very impressive.

jack had the exotics in a "bookshelf" stand mounted box when i asked how the two compared, although i think i remember him planning to do a multi-way design.

lack of and waiting for bass to develop over time as the drivers break in wrt a 138es-r/BLH build was one thing i think i was able to make out from japanese web site google translation, haven't found a follow-up.

*138 BLH design for anyone interested: http://makizouphoto.hp.infoseek.co.jp/furukawa7.html

[MDOFCR]

Originally posted by mp9

hi robert, been wondering what you've been up to. so a Multiple-Chamber Aligned in Parallel Cavity Resonator (MCAP-CR), don't know where you found it but looks interesting. keep us posted on the build (you may as well get on with it, (lol)). it's different and jack k. already did the nessie and didn't seem as enamored with them as he was with the exotic's unfiltered in a simple sealed box. he said something wrt the exotic/sealed enclosure having more bass output than a 138es-r/nessie. any idea how the mcap-cr concept is being accepted by other builders and by those who've been able to hear them?

Hi,

You will find detailed documents with equations of MCAP-CR in my pages. It is your decision if you believe my model of physics that represents multiple degree of freedom cavity resonators.

I will talk with Feastrex if there is any possibility for non Japanese residents to hear MCAP-CR. Hearing is believing a lot more than equations...

FE138ES-R will be a good example for MCAP-CR. I guess my TR130c will fit FE138ES-R. You need two of 3' x 6' x 18mm panels for TR130c cabinet.

Please email me, if you want to more about MCAP-CR.

Regards,

Shigeruhttp://www.geocities.com/sg_suzuki/index.html