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Old 15th May 2006, 06:25 PM   #1
no xo is offline no xo  United States
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Default Fostex HP reflectors

Has any one han expirience with these? The reason I ask is, I built the recommended horn for the FE206ESR and I have a peak around 150hz to 200hz, that makes them hard to listen to. The drivers have over 150hrs. on them, so I think it`s the horn. Would these reflectors or stuffing the cc help reduce this peak. I sed 1/4" adheasive foam covered with wool felt behind the driver, and everything else is according to Fostex plan. They are located in the room where I`ve never had a problem before. I feel I should have built Ron`s Dallas horn despite my limited woodworking skills.....
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Old 15th May 2006, 07:16 PM   #2
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No xo,

Although I have a different driver (108 Sigma) and different enclosure, I have similar questions: How to deal with frequency response once the things are built. So far, I have found that getting accurate measurements is far more difficult than dealing with the problem .

I did learn that near-field measurement of the horn mouth is accurate (up to 500Hz), so you might want to try that first to see exactly what you are getting from it.

I assume you have tried different room placements for the speakers and yourself. A room node might be messing up what you are hearing.

Doug
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Old 15th May 2006, 07:38 PM   #3
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Thanks for the reply. I don`t think it`s a room node, the Proac Response 1sc`s with sub, and the standard version of the FE206E in recommended horn did not have a problem. In fact both measured a little dip in that range, which is probably why the peak bothers me. Have you added stuffing in the cc or any other mods. The more I listen to these, the less I like them. After spending a fair amount of time and money I`m kinda bummed. If I turn up the volume to moderate levels they get worse and worse. Compared to the other horns (FE206E) there is just something wrong. I even wonder if my glue job was bad and there are some interior panels vibrating. I sure hope not because everything is square and I have lots of clamps and put 2 100lbs weights with serious clamps when I glued the final side on. Whatever I did, I messed up somewhere......now can I fix it?
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Old 15th May 2006, 08:33 PM   #4
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Yeah, if you don't like them, then you have to do something. That's the bottom line, I guess.

I'm sure your glue job is fine. That would be my least worry.

I did try suffing in the cc on mine, but it sucked too much life out of the midrange and messed up the soundstage. I don't recall it affecting the mid-bass, though.

You could try building an A/B switch like I use. It's really simple. The thread is about the middle of page 2 now. That way you can tweak a single speaker and compare it to the other. Start with at least 50% changes. For instance, if you want to see what effect stuffing has, take half the stuffing out of one speaker, or add 50% more, and then start narrowing it down to what helps with your problem. The switch will give you instant feedback of your changes.

I'm sorry you're going though this. I've been down that road too.

Doug
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Old 15th May 2006, 08:49 PM   #5
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Thanks for the advice. I would not have thought about changing one and comparing it to the other. I tried to keep stuffing minimal so dynamic range would be maximal. I plan to make some changes tonite and will post as progress is made. I have to fix these, there are positives on their overall sound, but that peak needs to go down some and we`ll be alright.
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Old 16th May 2006, 06:58 AM   #6
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NO XO,
I ran into the same problem on my 208 sigma horns. More stuffing in the cc solved the problem.
I'll be watching your progress as I intend to build the same horn for my 206esr's.
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Old 16th May 2006, 02:43 PM   #7
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Thanks for the reply. Last nite I added some polyfil to the cc and that helped, so I think we`re on the right track. I also plan to add damping to the magnet`s back and side, and put a piece of deflex at the bottom of the cc. I`ll try these one at a time so I don`t over do it. The polyfil did not hurt the dynamics and helped without any obvious negative side effects. I will post my progress.....I hope.
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Old 16th May 2006, 03:05 PM   #8
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That's really interesting because I got the exact opposite when I put stuffing in the cc. Any amount sucked the life out of them. I guess that's why there is no definative guide to tweaking speakers

I still haven't tried damping the magnet yet, however, and you have inspired me to get off my butt and do it!

Doug
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Old 16th May 2006, 08:39 PM   #9
no xo is offline no xo  United States
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Taperwood, what kind of stuffing did you use and how much of it? I used a small amount of polyfil from Parts Express, and pulled it apart as much as I could so it was loose, and filled the cc to about the bottom of the driver. The resonance is not totally gone and it sounded better,but my Rat Shack SPL meter deteced only 1db reduction, which I presumed would be inaudible...or incorrectly measured. The more I use the meter, the happier I am with tuning by ear. As in health and fitness, the mirror tells you more than the scale.
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Old 17th May 2006, 01:46 AM   #10
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Oh I just use the polyfill from the fabric store. I guess I'm not that picky. I've heard it's the same stuff. I tried about five different iterations of stuffing in the cc. After that I sort of gave up trying to get any improvement for now and concentrated on other things.

Ditto on the meter. It's a double-edged sword, and don't forget it's only accurate to +/- 2 dB. When I do frequency sweeps with it, it's always off by 1 or 2 dB when I return to my 1000Hz reference. I've decided the meter is good for zeroing in on what you know is wrong, but for fine tuning the ear is best.

If you stumble across anthing that tones down the mid/upper range a bit (3500-7500Hz), let me know.

Doug
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