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Message started by Azul Shiva on 07/18/14 at 21:33:58

Title: Serious Problem with FE206EN Driver
Post by Azul Shiva on 07/18/14 at 21:33:58

Hi

I know this aint really in the right section cos I dont have a DFR8 driver, but since the DFR is simply an improvement to the original Fostex Fe206 and you guys from decware have a lot of experience with the Fe206 I hope this can be excused.

The very first moment I played the fostex after freshly installing them into their cabinets I found myself forced to angle the left speaker about 30 degrees to the inside while the right one stared directly at me.

After 50 hours of listening and warming up the brand new drivers the problem persisted. The left speaker is severely annoying, lacks lower mid frequencies, and sounds cheap and ascetic and actually made me believe that the FE206 are very bad at high frequency reproduction. Take a look at the measurements I did using white noise, first picture is a measurement at 1m, 2nd picture at the listening position, blue line L speaker, red line R speaker (2 seperate measurements). The white noise played for about 60 seconds and the frequency spectrum analyzer was set to average. 3rd picture is the less important frequency response with sweeping sine waves of both speakers together recorded at the listening position, spectrum analyzer set at maximum.

For the past few days I found myself listening to the right speaker only. It wasnt always perfect either, however common sense told me that the rear of the mounted cone/horn ruins the sound by playing frequencies in reversed phase, so I applied some rockwool between the membrane and the cone. With great results!! It also damped the high frequencies by just the right amount and voices, especially Chers, sounded a lot more pure.
I did the same treat with the left speaker, decided it still sounds awful so I covered the entire cone generously with rockwool. The annoying resonances at mid-high frequencies (Im guessing the one at 5.1khz especially) are damped now, but they are not gone and the speaker is still lacking a lot in the lower mids. The frequency response up to 1khz sounds even worse than it measures. The rockwool treats made it possible to listen to both speakers at the same time without the left speaker ruining everything, but its not possible to continue like this. The right driver however is doing a great job..

Is this a frequent problem with fostex drivers and is there a way to fix this? Or should I just get the left driver replaced? And if they dont want to do that ill just have to buy a new one or what screw em ^^

Thanks in advance
regards,

Title: Re: Serious Problem with FE206EN Driver
Post by dank on 07/19/14 at 22:05:40

I'd swap speakers and be sure the bad sound follows the speaker, and not the speaker cabinet, and then try to get another speaker.

That dip at about 120hz in the 3rd picture could be caused by the speakers being placed too close to the wall(s).  I had just about the same thing happen to me (although it was around 200 hz).


Dan

Title: Re: Serious Problem with FE206EN Driver
Post by Azul Shiva on 07/19/14 at 23:04:03

Good idea, might be the cabinet.. Ill try that tomorrow.

Since all my music runs over my computer it makes things rather simple for me.. Ive preinstalled a few parametric equalizers with AudioMulch to get rid of some peaks and resonances and the left driver sounds a lot better, but I really believe something is broken because of the missing lower frequencies from the left speaker. When I tried to enhance them the entire sound became washed out..

BTW Fostex's measurements show a MASSIVE resonance at 2.75khz with the Fostex driver. If anyones got that driver running over a PC, a setting of -9db with a bandwith of around 500hz kills that peak totally leading to incredible improvement of the sound. Eliminating the 2.75khz resonance makes these speakers 10x better, and after only 2 hours of listening I couldnt possibly imagine going back to listening without the fix.

Oh and the dips at 120hz and 210 are from the cabinet, you can see the same dips at measurements of Fostex's recommended horn enclosures bk206 and bk208 (its ridiculous.. when i got sum spare 200-300 not knowing where to invest ill definately build the NFX or the openbaffle speaker that Steve Deckert designed, dude looks like he knows what hes doing..)

gratz, thanks for ur answer ill get that damn thing replaced

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