Upgrading MJ King's Open Baffle

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Roushon

Roushon

Member
2004-09-28 6:51 am
Mumbai (Bombay)
I built this about three years ago and since then it is a great pleasure listening to this.

http://www.diyaudio.com/forums/multi-way/167931-suitable-speakers-4.html

In the design MJ King suggests Fostex FE103en as the full range driver as it will also be cost effective. There are mentioned several other Fostex options in the article. Planning to upgrade (or may be it will not) replacing the
FE103en by FE108ez. Has anybody tried this before and if yes, kindly tell me how was the improvement. There is another reason for this (trying to) upgrading, one of the EF103en was damaged by custom official in India, although seems working OK.

Regards
Roushon.
 
picowallspeaker

picowallspeaker

Member
2007-04-19 4:12 pm
Hi Roushon !

:scratch1:

In the Foster 10 Thread, Howard asked me if I knew the King OB and it
reminded me of you, so there you are !

Studies had gone along these years :rolleyes: and I've come to conclude that:

Each speaker has to be fully suspended
The back wave has to be treated somehow
Three way is the optimum
 
Roushon

Roushon

Member
2004-09-28 6:51 am
Mumbai (Bombay)
Hi Pico!
Indeed it is always a pleasure to read your
replies. I just looked at the Foster 10 thread. I did have
some trouble in the beginning with bass and positioning of
the baffles. On your suggestion I did build a small bass
boost later on with a single op amp from Linkwitz site
`shelving lowpass'

Active Filters

Now I have the baffles about 4feet away from the back
wall and 1 and half away from the side walls. I can continue
listening to it without fatigue (of course it also depends on
the music!).

It will be helpful if you detail a bit your suggestions if
possible some site on three way baffle.

Edit: At some point I also thought of upgrading it to a H baffle.

Regards
Roushon.
 
Last edited:
picowallspeaker

picowallspeaker

Member
2007-04-19 4:12 pm
Number four: The woofer doesn't have to be bigger than 6-7''

So this leaves out any OB arrangement.
So what happens ? Once you take out the back wave, which is the negation of the front one, everything should be ok . But that is nearly impossible, because you need to build a wall to do that, and it wouldn't be good to have the speaker attached to the flat wall.
Attached is no good either. So you need to confine the sound, bound it somewhere away . As OB is good because the cone isn't affected by the bounces inside a box, it also
produces a positive event and a negative one; the sound from the back is the negation.
So the mind settles on what's good and eliminates the bad, but it's still there.
So the bordering ...
 
Jim Shearer

Jim Shearer

Member
2007-06-11 3:41 pm
eastern PA
Roushon said:
I built this about three years ago and since then it is a great pleasure listening to this.

http://www.diyaudio.com/forums/multi-way/167931-suitable-speakers-4.html

In the design MJ King suggests Fostex FE103en as the full range driver as it will also be cost effective. There are mentioned several other Fostex options in the article. Planning to upgrade (or may be it will not) replacing the
FE103en by FE108ez. Has anybody tried this before and if yes, kindly tell me how was the improvement. There is another reason for this (trying to) upgrading, one of the EF103en was damaged by custom official in India, although seems working OK.

Regards
Roushon.
Click to expand...


I have used both the FE103en and FE108eSigma. My opinion is that the FE103en is the better choice. Its sensitivity is a perfect match for the Alpha 15a in this configuration. The FE108eS is a bit more sensitive, and I expect you would want to pad it down.

The sonic character of the FE103en is a bit different from the FE108eS, but I frankly don't find one superior to the other--they are just different.

Cheers, Jim
 
Roushon

Roushon

Member
2004-09-28 6:51 am
Mumbai (Bombay)
Hi Jim,
Thanks for the information. That is an important and interesting fact. Already I had to use a little bass boost
to make the Alpha 15 audible, so FE108 seems will be a problem in this case. Now I think, Madisound gave the review of FE108 for advertisement only and not anybody's experience.

Regards
Roushon.
 
Jim Shearer

Jim Shearer

Member
2007-06-11 3:41 pm
eastern PA
Hi Roushon,

I use the now discontinued FF85K with the Alpha 15a on an MJK passive OB. At the time, the 85 was (IMO) the best match for the system as far as sensitivity was concerned. And I had used the 85 previously and really like the sound. The new FE103en is an equally good match for sensitivity, and it also is a VERY nice sounding driver. The 103 is (again, IMO) a smoother sounding driver than many of the Fostex line. The 108 is also great driver. I have used it on Metronomes and like it very much. But the 108 is more sensitive and a bit peaky--a quality which (at least for some people) makes it a very lively and exciting driver. In the Met, the 108 goes a bit deeper in the bass than the 103. Is the 108 worth the higher price? I really don't know if I would have paid the extra money if I had known about the 103 back then.

The 85, 103, and 108 are all very nice drivers. Each has its own character and qualities. Having used all three, I think you won't do any better swapping the 108 for the 103, but it's all a matter of personal preference.

Cheers, Jim
 
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