Infinity RS 4b Speakers

[Frankrentef]

Greetings all. My latest "dumpster diving" at my local thrift store revealed a set of Infinity RS 4b Speakers. Excellent condition for $5.00 each! Now that I have them.... what exactly do I have? Google is not yielding much info.

THNX!

[Army]

Hi Frank

Check out the thread: Information on the net, there are a number of links with good info.


PRODUCT SPECIFICATIONS

Frequency Response: 38Hz - 32kHz (+/-3dB)
Crossover Frequency(ies): 600Hz, 4kHz
Nominal Impedance: 4 ohms - 8 ohms
Recommended Power Amplifier Range: 40 - 150 watts RMS / channel
Woofer: 8" polypropelene
Midrange Driver: Polydome
Tweeter: EMIT



Have you hooked them up yet? How do they sound?

PS I moved this thread to the Infinity forum

[Kencat]

5$ each. That is incredible. No way you can go wrong if they work.....probably even if they require some work. Nice catch!

I've never heard any. Would like to hear your impressions. Pics would be nice too :yes:

[draftingmonkey]

Gee, my local GW has a pair priced at $30 each. Need new surrounds but not in to bad of shape. $5 bucks is a buy. I passed, at least for the moment.

[MacmanNM]

Those are some really good speakers. I had a pair back in the 80's and am sorry I ever got rid of them. Some of the best speakers for Jazz I have listenedt to. They were very power hungry though. I had to replace my woofers in the early 90's. I ended up using a pair of Pyle 8" drivers, I couldn't get new ones from Infinity and I couldn't find anyone to repair the drivers. They are well worth what you paid. They are also well worth repairing if you feel so inclined.

John

[Frankrentef]

Well, I've had to redo the foam around the edge ($30.00 kit) and they work great! Except for one of the 8" speakers has a vibration. I can put my finger with very little pressure at one place on the cone and the vibration stops. Any suggestions? Replace the speaker?

THNX

[Frankrentef]

Clarification... (I'm a newbie so look over my lack of terms) by cone I mean don't mean the center soft cone but the area between the center and foam.

[Army]

Sounds like you might have a little voice coil rub going on there Frank.

With the amp off push gently in on the woofer cone to see if you can feel it rub. If thats the case you'll need to carefully remove the outter edge of the surround from the basket, remove the dust cover, shim it and reglue it.

You could also remove the offending woofer and check it with a 9 volt battery to see if it rubs as well.

Other than that, I'm not sure what else you'd have going on there.

[Negotiableterms]

One other possible solution:

Once you figure out where the rub is, try rotating the woofer so that the rub point is at the top. There's a small chance that gravity will solve the problem for you. Worth trying before you involve a lot of work and/or money.

[Frankrentef]

THNX! I'll give these ideas a try.

[Frankrentef]

Help,

Vibration is present whenever I turn up to around 25+ watts. Does anyone have a "how to" link for dummies like me. I'd like to save these speakers, really sound sweet.

THNX

[Army]

Sorry Frank I can't think of a link that would help.

Sounds like you need to carefully remove the outter edge of the surround and shim the voice coil and reglue. Or refoam the offending woofer from scratch.

Which is the only way to get rid of voice coil rub, if turning the woofer 180 degrees didn't work.

[Frankrentef]

Thnx,

So I cut out (almost but not totally) the center "surround". Take something akin to a business card and shim up the speaker (allow the center of the speaker cone to rest on the top of the card) and then reglue the center.

Yes?

[Army]

Remove either side of the surround inner or outter. I usually do the outter.

Remove the dust cap carefully and shim so that it just barely moves up and down.

Reglue and then glue the dust cap back on. Use a straw after you apply the glue and hold it (dust cap) with suction and place it back on center.

Should fix it right up!

[Frankrentef]

Dust Cap equals the "dome" in the center, yes? I'm trying to find a breakdown of speaker parts with the corrent names but as yet to find it.

THNX

[Frankrentef]

Make that "corrent" "correct". Sorry for the typo.

[Frankrentef]

Something like this?

http://www.decware.com/newsite/refoam.htm

[Kencat]

Dust Cap equals the "dome" in the center, yes? I'm trying to find a breakdown of speaker parts with the corrent names but as yet to find it.

THNX

http://www.tnt-audio.com/clinica/foamrepair_e.html

http://www.decware.com/newsite/refoam.htm

This one has a video to watch
http://www.wooferrepair.com/faq.html

This should get you started. I did a google on " how to shim voice coil" and got a bunch.

[Frankrentef]

THNX,

As always, knowing how to ask the right question is the best way to find the answer.

[Army]

Thanks Ken, I had one of those book marked a while ago. But they didn't make the tranfer to the new puter, then I forgot about them.

Good reference resource :thmbsp:

[Army]

Didn't think of this till I read this post (http://audiokarma.org/forums/showpost.php?p=685677&postcount=1)


Might check to make sure Frank, if you haven't torn the woofer down yet!

[Kencat]

Guys,

That video is VERY good. I sat and watched the whole 20 odd minutes of it.....and learned a few things too :thmbsp:

worth watching even if you THiNK you are an ace :naughty: :D

[Frankrentef]

I'm NOT an ace.... but I'm willing to learn. The instructions that came with the foam and glue mentioned nothing about the coil, etc. So, I have the new foam on and I'm guessing I need to take it back off, order some more and start over?

THNX for all the help!

[Don C]

If the voice coil is rubbing, it should be possible to feel that when you press (gently end evenly) on the cone. Other things that can cause problems sometimes would be a gap in the glue holding the surround, or a wire slapping the cone from inside the cabinet. If it is the voice coil rubbing, yes, you can usually order another refoam kit and fix it.

[Kencat]

Frank,

What Don C was saying was good advice. Before ripping apart your refoam job, eliminate the other potential and simpler causes first.

You haven't said yet whether you can actually feel a rub when you gently push down on the cone (no power on when doing it). Probably best to have the woofer out and laying magnet down on a table or the floor so you can better feel that you are pushing evenly or squarely.

I kind of wonder if it is VC rub when you say the vibration only begins at high power levels. Anyone else with a feel for this? Would a VC rub not be evident even at low levels?

Are these a ported speaker ? If not, perhaps the box is not sealed well and the woofer is not as controlloed as it should be. IS there a gasket ( in good shape) between the woofer and baffle board?

Keep us posted on your progress. We all learn from little problems like this. Never know when it may happen to any of us .

[Frankrentef]

I don't feel a rub when mounted in the cabinet. I'll pull them this weekend and see how laying them flat on the table works.

THNX for all the help and advice.