Fostex studio speakers repair

I’m looking to replace or rebuild two 3" woofers.

I looked up the number on the back of the speaker (8h221), but no relevant results.

I also search for the speakers model number (SS-1), but didn’t find much with that either.

So I’m looking at

Or maybe something like this

I want the speakers to sound as close to original as possible.

I couldn’t find any spec sheets either, so I don’t even know what Ohms they are.

This is the complete system.

You may have guessed, but it’s likely they’ll be 6-8 ohms. Fostex makes real audio shit, so I’d take a gander that they stick to either 4, 8, or 16. I’ll guess 8, for those.

Anyway, the cones appear unbent, so you have a good chance at restoring them, if you know how. I wish I could help further, but I don’t know how to repair speakers. Perhaps one day. Let us know how you get along!

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I was thinking about taking the sub apart to see if it would mention the Ohms somewhere in there (like on the amp). I wouldn’t be surprised if the sub has a different Ohm rating from the speakers.

If I do rebuild them (well replace the surrounding) it will be my first time.

I plan to post my progress here.

why? go to harbor freight and get yourself one of their cheapo multimeters. Sometimes they are free if you buy something else at the store.

Set your meter for ohms, set the speakers flat on a table and put your meter leads to the wires coming off the woofer.

Boom, it will tell you the exact impedance.

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I actually did that. I don’t remember what it was, but it seemed like a bit of an odd number, so I just assumed it wasn’t that easy. I’ll check the other speaker when I get back from work.

edit: I think it was .3 Ohms.

I tested the other speaker and came up with 2.8 Ohm.

So if I had to guess the voice coils are shorted a bit.

I’m going to test my multimeter to make sure it’s working properly.

edit: got a Harbor Freight multimeter and it reads both speakers at 3.9 Ohms. Guess my multimeter is inaccurate.

Probably just needs a new battery. When a multimeter runs low, it throws everything else out of wack.

You have a few options on the table. Only one of which gets you stock-ish performance.

1: refoam. Use the pioneer foam and hope for the best. It may or may not work. Not all foam is equal, so its hard to say what success you will have.

2: different drivers. This will change the sound. It is probably your most risky option. You could easily end up with something that sounds out of wack. But there is a small chance it can be better. I would say that even if you knew every single detail and spec of your drivers, there is about a 10% chance you could be successful.

3: Just build new speakers. This sounds crazy, but think about it. The pioneer foam is 23 bucks, new drivers would be closer to 30 bucks.

Peerless makes a 3 inch full range driver that goes from 57hz to 20K for 54 bucks a pair

You get a pair of those, you go to home depot and have them cut up some MDF for you. You get a 3 inch hole saw and punch out some holes and glue everything together. You would end up with a pretty bad ass set of speakers for pennies on the dollar.


Dumb question, but why fix them? If your buying drivers, just get the best drivers you can and spec a crossover and box around that… its only mdf, so a handsaw and glue and or a few screws (which can again be done by hand) is all it takes.

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I’ve been toying around with that idea. I’ve been doing a bunch of research on making a good flat sounding setup. I’ve also been dabbling on passive radiators, but I haven’t found much info yet.

I replaced it with a new one, but unfortunately didn’t help this time.

Fostex is supposed to have extremely high end studio speakers. These are the most true sounding speakers I’ve ever heard (not that I’ve heard very many studio setups), and I’d like to keep the sound as true as possible.
I am thinking about building something, but either way I’ll be fixing these.

I should mention this system has a sub as well with an amp built to power all the speakers.

I’ll add a picture of the complete system when I get home.

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@TeckMonster did you ever fix it?

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In speaking of Fostex repair, my TH500RP cans now only work in one ear. I assume its a damaged cord going to the side that doesnt work but because im so terrible at soldering I never attempted a fix. Also dont have a way of telling where in the 3 meter cord it could be damaged.

Not too much of a big deal because I replaced them with the Audeze EL-8 open-back, but still would be nice to have them working again, its a great sounding pair of cans.

Get a multi-meter, attach a normal 1.5v battery to the contacts on the plug, look for voltage starting at the speaker, and testing after each connection till you find it. If its somewhere in the cord, don’t bother to pierce the insulation to find it, the wire is a pain to get a good solder connection to anyway, just replace the entire cord from where it leaves the headphones… TRS extensions are very cheap, and if you get one designed to run passive monitors, the extra copper makes it easy to work on.


I might experiment with your solution, these cans dont have removable cables but since they’re dead to me anyway, might as well dissect them.


I haven’t. I got distracted with other projects. I got on Amazon to order those speakers, but they’re only available from third-party sellers, so I’m going to have to find another set.

I’ve got the same speakers, same problem. Not sure if the tweeters are ok or not (will test eventually) but the woofers sounded fried so when I opened up the cases I saw the same thing you’re showing here.

As for refoaming them, man, I dunno. I just finished a refoam job on a pair of vintage JBL L40’s, my first such job, and it was stressful, though ultimately successful. Here, they’re just so small! I have big fingers! I might just replace. The drivers you mention as candidates seem like good choices. I would love to try the Faital 3FE25s, but they seem just a bit too big physically, screw-to-screw, to fit. But the Peerless seem like a good substitute. I’ll let y’all know if I actually get to do this. They’ve been kicking around unused for a few years already, I may have to re-shelve them and finish my Magneplanars before getting back to these!

Oh, I did want to add though, they’re not MDF, they’re some kind of plastic resin case. It’s all one piece molded box, with a separate removable front panel. Zero insulation inside, big copper (?) plate in the bottom for… mass? Not sure. Some of us don’t like to throw stuff like this away; would rather repair than dispose. They seem a pretty good start; I’d hate to see them just end up in the landfill.

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I ended going to a thrift shop and picked up some Onkyo bookshelf speakers, that are surprisingly good, so I probably won’t do anything with OG speakers now. My sub still works great, so just needed the bookshelf speakers.

Yeah! Definitely do that. I’d love to see what you do with these great systems. Feel free to start a thread about it when your ready.

And hey, welcome to the Level 1 Techs forums!

Unfortunately this thread has been dead for 12 months so I’m going to have to close it. Feel free to PM me if you have any questions.

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