New MJK Baffle Article

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ronc said:
So the end result is after two degrees in college and 30 years of building /designing speakers and endless computer program design and development projects, endless study into acoustics and the physics behind the actions is:

I have a flat panel of plywood holding two drivers with some electronics sitting in my living room with near 50 year old amplification.

Makes me think.

ron


someone with your background and experience saying this, I wonder whether we should be bothered spending time and money researching into development of new speakers designs or just stick with a flat panel and a few high quality drivers attached.

this I think is a retrograde step as there will be no new advances on speakers design in future.

Having said that I think one can build a set of high quality speakers comparable to the current breed of modern speakers without spending heaps of money.
 
wixy said:
Anyone have some tips on materials to use for the MJK baffle?

What thickness is best?

The pioneers of audio did extensive testing of every aspect of audio system design and concluded that 1" thick marine grade no-void plywood was sufficiently rigid/damped for apps with up to a 500 Hz XO point, so laminating Baltic Birch or similar to reach the desired thickness or liberally bracing thinner material now that marine grade is no longer guaranteed no-void AFAIK, it seems the simple, 'no-brainer' choice to me: http://www.audioanthology.com/audio4.htm

GM
 
just laminate it - woodgrain, arty farty finish, whatever. For a serious challenge, try finishing off the concrete spheres to the "good woman's" satisfaction Incidently, are the Coral (or Peak) 8CX50's any good to you guys - have a spare pair in very good nick - not using them, prefer beta 8 and 10s.

Cheers ... James
 
sonido ?

First of all i would like to thanks MJK for sharing his gr8 work!:wave2:
I am currently stuck with U baffle trying to integrate Alpha 15" ,alpha 6.5" and selenium st324 ( "All eminence OB" thread).I have some problems with crossing over to selenium tweet and also 6,5's 93.6db SPL is somehow problematic and sounds kinda raw.Therefore i decided to sell them and buy this one instead.Would anyone know how would they perform in my setup with Alpha's ?
 
You will need an L-Pad for that driver. I figure around a 10 db difference is around right.

IMHO i still would go with a higher Qts driver, it just blends in better with the 15A.

NOW! lets work on getting the LF response lower and do something about the edge diffraction.

One of the major problems i see with OBs (besides the depth of LF response) is the edge diffraction. In my sims i see its twice that of a normal cab (makes sense). There are all kinds of later timed weaker wavefronts that are being produced at various frequencies and emitting at various angles.

First thought, a 3" od piece of PVC with a slit cut to accomodate the baffle T and being placed on the L,R and upper edges.

ron
 
ronc said:
NOW! lets work on getting the LF response lower and do something about the edge diffraction.


I don't have a clue how to fix the edge diffraction, but it's possible to get great LF out of an OB. I'm currently using a pair of Fostex 108E Sigmas actively crossed over to four Acoustic Elegance Lambda Dipole 15 inch drivers. (Two Lambdas per channel.) The drivers are mounted on temporary baffles that measure 46 by 20 inches. This OB set blows away my 166esr Swans in that LF "slam." I can't help but smile every time I hear the cannon shots in the 1812 Overture! Unfortunately, four of the Lambdas cost $1,000 US so it is not a budget project. In addition, the Lambdas might not be available anymore.

Rich
 
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