Infinity RS-IIIa - Worth restoring, or not?

If you power the speaker as usual with only the EMIT connected you will have the protection the crossover and fuse provide. It would probably be wise to make sure the disconnected mid range and woofer wires don't touch one another. I think. Someone can correct if wrong.

THIS IS IMPORTANT--if you connect just the EMIT to an amp/receiver it will NOT be protected by either the fuse or the crossover preventing bass and midrange frequencies getting to it.
I would not play just the EMITs by themselves crazy loud.
But that's just me.


Perfectly flat EMIT diaphragms are fairly rare.
Most seem to have at least a little waviness so that is not cause for alarm.
When the little shiny strip is broken the EMIT stops producing sound. That is not the only reason they won't produce sound however.
That little shiny strip goes in oblong circles on the diaphragm from terminal to terminal.
The resistance check you did confirms that the "trace" (shiny silver strip) is continuous and not broken.
 
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I've owned around ten pair of Infinity speakers with emits. Never blown one ever as they are very durable. Those speakers will perform okay with that toshiba but down the road you may want to buy and amp with around 150 watts or so. This would insure your amp won't clip and blow the tweeters (hopefully the fuse).
Good luck with the repairs. Those are fine looking and sounding speakers. Who ever gave you them is a very generous person.
 
My EMITs both measured at 3.4-3.6 ohms. Can anyone think of an actual, real-life example - or of a hypothetical scenario - in which an EMIT tweeter with the correct resistance plays as expected at low volume, but not at high volume - and the problem was due to a fault with the EMIT, itself?

I had an EMIT on a Qb that tested fine and would play for a few seconds then go silent. I reflowed the soldier buttons on the tweeter and it has worked fine ever since.

That 4khz crossover point isn't accurate, at least on the Quantum's although this is what the Infinity documentation states. I tested the crossover point to the EMIT's both on my rebuilt crossovers and on the original prior to the rebuild. At the low crossover point setting its about 2500hz. At the high crossover setting its about 2800hz. I highly doubt the EMIT's in these speakers cross at 4000hz . This might have been Infinity propaganda at the time for whatever reason. Not that it matters, just passing along some info.

I tested my QLS-1 last night with an on line tone generator. They crossed over at 4,000 Hz in the middle setting, 4,400Hz on high and 3,600Hz on low. I can't verify how accurate the free tone generator actually is... Maybe someone with more knowledge than me could math out the crossover parts?
 
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I have been testing the EMIT in one of the Infinity RS-3a. Right now, the EMIT is the only speaker in the cabinet. To recap, my test amp is a Toshiba SA-850, 55W @ 8 ohms, 70W @ 4 ohms. Source is a not-great FM signal, and I have the balance knob rotated to only the left channel which is connected to the test speaker.

When the volume dial on the Toshiba is between 2 and 4, it sounds a bit weak and tinny, but otherwise, OK. That may be normal with only the tweeter playing (?) There is a little hiss, as expected with the marginal FM signal, but no static when the potentiometer dial is twisted. I haven't used the old Toshiba in a long while, but as I recall, I would normally set the volume dial beteen 2 and 4 when driving my old AR-15 speakers. I rarely set it above 5 or 6, but when I did, no problems.

Today, if I increase the volume knob to 5 (the 12 o'clock position = halfway) after a short period - less than a minute - I hear a click, followed by silence. After a few seconds, another click, and the sound comes back. At which point I quit testing. I'm pretty sure the click is coming from the amp - probably some kind of overload protection kicking in (?) The Toshiba manual says "Using a recently developed IC, the SA-850 fully protects the internal circuitry from possible harm due to speaker cable short circuits, current overloads, and the accidental appearance of DC voltage at the output terminals."

So, now I don't know if I have a problem with the old amp - or if some fault with the RS-3a is triggering the protection - or if my abnormal test setup is causing unrealistic demands on the amp.
 
Do you have another amp to try? That is the best way to eliminated that possibility.

Yes, but I am reluctant to risk frying one of my "good" amps if the speaker has something pathological going on. Also, it would require either carrying that big monster speaker upstairs - or disconnecting everything from my in-use setup, and putting it all back together later. Neither option is very attractive.

I did take one of my smaller speakers down to the test amp and it play long and loud with volume knob set to 7. May not be a fair test because it is a more efficient speaker (?)
 
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Yes, when I move the speaker wire from the left channel to the right, it still trips the protection on the amp.
See if the ARs cause the amp to go into protect.
Try a different amp on the IIIas.
Look for shorting wires at speaker terminals etc.
Push comes to shove , bail you are in the wrong hobby:whip:
 
When I move the EMIT from the other speaker "B" into my test cabinet "A" (which is the one with all other drivers removed), then the amp still goes into protection above volume = 5.

When I power cabinet B, with all drivers installed, I can run at volume 5 or 6 without triggering protection.

Conclusion, it's probably not the EMIT(s) triggering the amp protection unless they both have the same freakish problem.

Still need to determine if there is something wrong with the wiring/circuits in cabinet A - or if there is something unworkable about my test environment.

Maybe running the box with only the EMIT installed is the problem? I don't understand the ohms thing. Let's say the ohms rating of the total enclosure is 4 ohms. Is that a cumulative number, determined by adding the resistance of the various components inside - or is determined by which ever single component has the highest resistance? That is, without the other drivers installed, is it possible the single EMIT is somehow below the 4 ohm minimum my amp wants? (Actually, outside of the cabinet, I know it is, because I measured it at 3.4-3.6.) My multimeter won't give me a reading of either enclosure at the speaker wire terminals - is that normal and expected? By 'either enclosure' I mean with or without all the drivers installed.

As for me being in the wrong hobby, I thought I made that clear from the start.
 
As for me being in the wrong hobby, I thought I made that clear from the start.
Repeatedly so.

As to the amp going into protection mode, make sure any disconnected cabinet wires are not touching together as that would cause amp protect.
Also, hooking up your other speakers will show whether the amp has a problem.
 
After re-installing the midrange in cabinet A, and moving the woofers from cabinet B into cabinet A, I can now run cabinet A just fine at volume setting 6-7. The problem seems to be the flawed idea that it is OK to run the EMIT, only, in a cabinet. It may be that crossober / fuse protects the EMIT, but my amp did not like that setup.

Since the foam surrounds on the woofers are significantly deteriorated, I had the bass tone control set to minimum for my test, and I did not expect a balanced sound. But my initial impression is that the very high end sounds a bit sibilant, harsh and brittle to me. And I like a bright sound. Obviously, it's far too soon to pass judgement under such poor conditions. And watching the woofers blow bits of their foam surrounds out into the room made me nervous, so the test was short. I guess I'll have to wait until the woofers are refoamed before I can determine if the EMITs are OK.
 
Repeatedly so.

As to the amp going into protection mode, make sure any disconnected cabinet wires are not touching together as that would cause amp protect.
Also, hooking up your other speakers will show whether the amp has a problem.
Done and done. But no longer an issue; read above.
 
I agree, re-foam the woofers, squirt the pots, double check the wiring diagram, (these Infinity drivers are all in phase) and put them back together. It will be the best way to discover how you feel about their sound and whether or not there is a problem with the EMIT. If the cutting out continues, I can walk you through the fix I used.
 
After re-installing the midrange in cabinet A, and moving the woofers from cabinet B into cabinet A, I can now run cabinet A just fine at volume setting 6-7. The problem seems to be the flawed idea that it is OK to run the EMIT, only, in a cabinet. It may be that crossober / fuse protects the EMIT, but my amp did not like that setup.
More likely you un-shorted any crossed loose wires when you reinstalled the drivers:beerchug:
 
I agree, re-foam the woofers, squirt the pots, double check the wiring diagram, (these Infinity drivers are all in phase) and put them back together. It will be the best way to discover how you feel about their sound and whether or not there is a problem with the EMIT. If the cutting out continues, I can walk you through the fix I used.
Although the diagram doesn't show it. the woofers should be wired in series.
 
To the OP, make sure you reconnect the woofers properly after the refoam project.
Many times they are not reconnected properly, failure to do so will result in poor bass performance.
 
More likely you un-shorted any crossed loose wires when you reinstalled the drivers:beerchug:
Well, they would have had a hard time shorting through the electrical tape and 3" of air I put between all the loose wire-ends before any power went into the cabinet. Just curious, but wouldn't a direct short trigger an immediate shutdown rather than waiting almost a minute after I turned up the volume? I may be a newbie to audio electronics, but the concept of a short circuit is not new to me. I've rewired half my house and it hasn't burned down yet. [Sorry, but I'm terrible with emoticons, so I don't know which animated GIF I should insert here; please advise.]

To goodolpg: I was delighted to discover all of the wires and terminals inside the cabinets were clearly marked by the factory with plus and minus signs AND color coded, as well - so I did not need to follow my usual routine of labeling everything myself. (The concept of polarity as it affects in-phase vs. out-of-phase speakers is also not new to me.)

Thanks again for the helpful answers and your patience.
 
That's good Gary.
There have been numerous threads about lack of bass (often after refoaming speakers), and some have been about Infinitys that have dual woofers. Sounds like you won't need to start one of your own.
Being old, I usually take pictures and label the wires also. Just in case I forget before I reassemble whatever I'm working on.
 
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