Open baffle fe127e with BR woofer

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Hi there,

I have a new project of loudspeaker. I was thinking about a fostex 127e, which I have heard a lot of good things as a medium, on an open baffle with a 12" woofer in a closed box or BR.

These will be driven by a gainclone lm3886 and an usb dac (my macbook will be the source with all my albums in Apple lossless). At the beggening it will be passive filter and later I will bought a DCX2496 with a pure class A for the fostex.

Was this kind of loudspeaker done by someone here ?
Is it a good idea ?

Simon.
 
Salut Camarade !

The MJK project is here :
http://www.quarter-wave.com/OBs/OB_Design.pdf

My opinion, a FE127 is too small to do all the midrange (150-1500Hz) in an OB, I will use it above 800Hz in the upper midrange.
Use instead the 12" a 8" or 2x7" in a (want you want) box. A 8" can easily handle the frequency until 800Hz.
If you want to use a 12" until 300Hz, choose instead a 7" or a 8" for midrange.

This project is very difficult. OBs are not easy to understand, not so easy to find a good geometry (etc.) but the results are worth the efforts to design them

Have fun.
 
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I agree with Dave, the 127 should do just fine. A 4.5 or 6.5 driver is great for this job.

As noted above, you should stay away from BR for your woofer. It can be done right to match the OB, but "Mille sabords!" as le Cpt. Haddock would say - it is difficult.

Best to stay with sealed box or OB bass for this. Each has its good and bad points.
 
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Work in reverse. What size box do you want? Or what is the biggest you will allow? Then look for a driver to go in that size.

And unless you are bi-amping, you don't want a woofer that is more sensitive in the sealed box than your Fostex. You don't want to attenuate the woofer!
 
You're right, I won't attenuate the woofer, I was looking for a woofer not more sensitive than the fostex (not less neither).
I want the closed box to be (max) 90cm high, 40 large and 60 deep with 30 mm mdf so it is approximately 150 L.

I have found the Monacor SPP 300, in 135L closed box I have this simulation :
An externally hosted image should be here but it was not working when we last tested it.


What do you think ? Is it a good one ?

Simon.
 
aliens exist said:
Thanks. First time I thought that a closed box would be better and after a lot of reading I changed my mind. But I can't do an OB for a woofer it would be too big for my room.


You can, with two 12 inchers per side (unless your room is very small or very resonant and one is enough, like in my case), and a little equalization or t-bass or the bass boost built in in the "subwoofer" amp
 
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