Feastrex/Hawthorne Augie OB by Dick Olsher

Russell Dawkins · « **on:** 15 Jan 2007, 09:05 pm »

Here's something to ponder and drool over! (just posted in Enjoy The Music)

http://www.enjoythemusic.com/magazine/equipment/0107/diy_loudspeaker_project.htm

I would want to find some way of mounting the Feastrex in plexiglass just to be able to see the back.

JohninCR · « **Reply #1 on:** 15 Jan 2007, 10:01 pm »

I'd use wood, but with minimal baffle to show off those beauties. I can't believe they put them on those big ugly rectangles. I thought those Feastrex were going to be in the $3k/pr range, but at about half that it may be a project in the foreseeable future. I'll have to start talking to Santa now. Thanks for the link.

Russell Dawkins · « **Reply #2 on:** 15 Jan 2007, 10:29 pm »

I'd like to use Plexi or actual glass, if only for the upper portion, if I were using a baffle shaped anything like the NoBox baffle, unless it really had a bad effect on the sound.

Do you think it would, John? What about the compromise of wood lower section and plexi upper?

I imagine Dick is using the NoBox baffle for because it is working so well for him with the Augie.

I think you are about right with your idea of the pricing. When I contacted Yukihito Akiyama back in January last year he mentioned a retail price of $1288 each.

My main concern with this design is the overall loudness potential/cost ratio. Somehow I wonder if the best 5 incher in the world (which I'm ready to believe this might be) is going to be able to play loud enough, even used only from 150 or 200 Hz and up.

JohninCR · « **Reply #3 on:** 16 Jan 2007, 12:03 am »

I've looked into glass and plexy, and down here glass is far more economical, plus the edges will look better. Going that route, I'd go all glass and isolate the woofer via a stainless steel magnet mount. Something like that would be all about looks. With a small driver, I believe with a large baffle is a compromise, and once you go multi-way I don't see much point in it. The technical types like Linkwitz, John K, et al use small flat baffles for the wide range drivers. One of our friends from across the pond mentioned that one of the scientific types gave a rule of thumb of something like max width of 2.2 times the driver. The only thing smaller than an 8 that I've used on OB are my FE108ESigma's on this baffle:

Small changes made significant sonic differences as I shaped this baffle, so if you fold at all around something running high in frequency you'll want to do some wooden prototypes first.

If I had a pair of the Feastrex drivers, I'd do a lot of testing first in a effort to optimize something like the circular baffle rings I did for the B200 discussed in the diffraction ring thread. I believe there is some significant gain there related to perfecting the point source sound. In direct comparisons to rectagular shaped baffles, the rectangular baffle were easy to hear as a sound source in addition to the driver due to edge diffraction. Maybe a cylindrical form would be ideal and avoid the problems inherent with a circular baffle. Too much exploring left for me to do before I buy drivers that are $1600/pr.

Christopher Witmer · « **Reply #4 on:** 27 Jan 2007, 05:52 am »

Here are some more good reasons to use glass or plexiglass, although I'd like to see the whole frame done in gold too (gold plating a brass or bronze phase plug would be easy enough, I should think):

In case anyone is wondering about the rationale for gold plating a part of the driver that is normally not visible to the eye, the reason (I am told) has everything to do with the sound.

I have not confirmed this myself but the principals of Feastrex believe the gold finish version sounds even better than the standard model with its black unichrome finish. Anyway, my understanding is that the only difference between the black unichrome version and the gold version is the plating. Iron can't be plated directly with gold, so they first apply copper, then nickel, and finally gold.

Okay, now to the last photo, the one with "rejects" in the name. The two motors in front are rejects because the second layer of plating (nickel) got messed up by the plating subcontractor. This was the first time to use this plating subcontractor and this was a learning experience for them. The problem is easy to prevent and is not likely to recur in the future. They decided to go ahead with the final gold plating layer on them anyway because the parts are too preciou$ to just throw away. Those will become my units, and I will have no reason to complain because I sit in front of my speakers (facing the business end, not fondling their backsides) when they're playing anyway . . . and I have determined that I shall not cringe at any "sonic distortion" resulting from a few microns' variation in the thickness of one of the layers of electroplate.

After having listened to the D5nf at shows so many times, I'm excited about the prospect of finally getting my hands on a pair . . . any pair. (Where's the smilie for SHEER LUST?)