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#1 2007-09-28 07:58:24

awhite1159
Member
From: Glenwood, NJ
Registered: 2007-04-07

FE208E Sigma w T90A cap value recommended by Fostex

I currently have a FE208E BLH and T90A supertweeters. I am using the recommended cap value of 1 uF. Is this recommendation by Fostex overly optimistic as to the range of the FE208E S? It sounds good to me but my ears only go to about 14k. I am just showing concern for other listeners and would not want to deprive them of the full audio spectrum. smile Seriously though should I use a slightly higher value? I have 1.5uF and 2uF laying around.


Andy

"If you think you are going to fail, you already have."

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#2 2007-09-28 08:35:57

karlsonkab
Member
Registered: 2006-03-21

Re: FE208E Sigma w T90A cap value recommended by Fostex

whats it look like on axis and 20 off axis with TrueRTA?  got any 0.1-0.2uF caps to parallel with 1uF and compare to 1.5uF?

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#3 2007-10-01 19:57:27

moiDeb
Member
Registered: 2005-07-31

Re: FE208E Sigma w T90A cap value recommended by Fostex

We e-mailed Fostex and they told us to install a 0,68 uF with reverse phase for the FE-208ES and the T-90A's.

Recommended cap value of 1.0 was for the FE-208ES with the T900A's.

Last edited by moiDeb (2007-10-01 20:03:18)

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#4 2007-10-18 13:34:57

dondiba
Member
Registered: 2007-10-16

Re: FE208E Sigma w T90A cap value recommended by Fostex

thank you
this is a useful information
i would have done the same mistake

by the way, what do you mean by "reverse phase"?

Dondiba

Last edited by dondiba (2007-10-18 13:36:30)

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#5 2007-10-19 12:07:03

coredump
Member
Registered: 2005-08-07

Re: FE208E Sigma w T90A cap value recommended by Fostex

moiDeb probably meant that the "+" one the amp's output should be connected to the tweeter's "-" and vice versa; this technique can be used to tackle some phase problems one might run into. You also could experiment with the tweeter's horizontal position on the speaker, as the wavelength at this frequency is quite small, and millimeters can make a difference here.

Just to make sure: your amp can handle the low impedance you get with the tweeter in parallel?

Best,
Oliver

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#6 2007-10-19 21:24:14

moiDeb
Member
Registered: 2005-07-31

Re: FE208E Sigma w T90A cap value recommended by Fostex

coredump wrote:

moiDeb probably meant that the "+" one the amp's output should be connected to the tweeter's "-" and vice versa; this technique can be used to tackle some phase problems one might run into. You also could experiment with the tweeter's horizontal position on the speaker, as the wavelength at this frequency is quite small, and millimeters can make a difference here.

Just to make sure: your amp can handle the low impedance you get with the tweeter in parallel?

Best,
Oliver

reverse_phase.jpg

Last edited by moiDeb (2007-10-19 21:24:49)

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