Infinity RSIIIB Restoration Project

[marantzfan]

Recently found some RSIIIB's on the local CL for $100. Needless to say, I ran over there and grabbed them. Now, I don't know much about these speakers aside from their positive reputaion. They are awfully dirty and all woofers need to be refoamed, but other than that they *look* ok.

My questions are 1. how do I test the midrange and tweeters to make sure they are performing within factory spec. 2. Is there anything special that needs to be done while refoaming the woofers and how can I verify that the voice coils are ok?

Other than that, I have already started cleaning up the cabinets and getting them presentable looking. Picutes to follow soon..

[rabbit]

For a start check the continuity of all of the voice coils using a multimeter set to Rx1 range or a digital multimeter. They all should measure between 3-6 ohms and similar drivers should measure almost identically to each other.

[Tedrick]

Nice score for one Franklin.

RE: Q#1: agree with Rabbit. Disconnect each driver and measure the resistance of each. If they all ohm out OK, they should be fine. The EMITs should be between 3.0 and 3.5 ohms, and woofers should be in that same range. Not sure about the Polydomes however. I'll try to pull out some of my spares and measure them tomorrow, and post the findings here.

In regards to refoaming, I'll let someone more experienced answer that one.

[marantzfan]

Well, refoam kit is here, but it recommend removing the dustcaps in order to shim the voice coils. That doesn't look too feasible on these woofers though...

I'ver heard something before about using a tone generator..Is that what I need to do, and what is a tone generator/where can I find one?

[VintInfinity]

There is a free program called Audacity, you can generate a continuous 30hz tone and then burn it to a CD or play it directly from the computer.

[Tedrick]

Whoa, I had a total brain freeze and forgot to post the DMM readings (please forgive). I tested two Polydomes and got 3.4 and 3.7 ohms, in the same range as the EMITs and the woofers.

On the refoam, you'll want to try and do it without cutting out the dust covers off. Something about the bullet shape contributes to the woofers' performance.

[marantzfan]

So, do I connect each woofer to an amp that is playing a certian tone? Seems like that would be kinda dificult..Like shooting a moving target...:scratch2:

[marantzfan]

Alright, tested all drivers with a dmm. Readings are as follows:

Woofers: 3.4, 3.5

Polydomes: 3.5, 3.7

EMIT: 2.7, 2.9

So I think everything is in line there, now I have downloaded audacity and am ready to go for the refoam. Is there a simple way to connect the drivers to my computer or do I have to go through an amp to do this?

[VintInfinity]

Yes, you will need to go to an amp first. Just hook the output from the computer to the preamp->amp->speaker like a normal source.

And I'm pretty sure you should do one at a time.

You may want to do some more reading so you are sure of what to do.

[marantzfan]

Yes, you will need to go to an amp first. Just hook the output from the computer to the preamp->amp->speaker like a normal source.

And I'm pretty sure you should do one at a time.

You may want to do some more reading so you are sure of what to do.

Will do. Any suggestions on where to find said reading?

[VintInfinity]

Search AK and google

[marantzfan]

Attaching the foams to the cones now. Got the audacity tone and an amp ready for tomorrow when I attach the basket side.

Looking really good so far!:thmbsp:

[VintInfinity]

:thmbsp:

Be sure to increase the length of the tone if you haven't already; it is 30 seconds by default.

[marantzfan]

What's the best tone to use? 30hz?

[marantzfan]

Alright, time to hook the woofers back up, the refoam job came out pretty good I think. Seems like these are relatively easy to center when refoaming.

Now, probably a stupid question, but being as a pair of woofers was already out of the cabs when I bought them, I don't know the correct wiring for these. Is it the same top and bottom for both woofers? Which one is purple and which one is red?:scratch2:

[marantzfan]

Alright, time to hook the woofers back up, the refoam job came out pretty good I think. Seems like these are relatively easy to center when refoaming.

Now, probably a stupid question, but being as a pair of woofers was already out of the cabs when I bought them, I don't know the correct wiring for these. Is it the same top and bottom for both woofers? Which one is purple and which one is red?:scratch2:

Found the correct wiring diagram on Infinity's website, got em hooked up correctly. Replaced the foam sheets on the front faces and replaced the grill clothes. I found some NM Infiity badges on ebay for $7.95 that are on their way and these will be DONE! The cabinets came out really good, only a few scratches that remained visible..

Can't wait to give them a listen.. Time to see if they can unseat the AR9's..:scratch2:

[chameloman72]

Found the correct wiring diagram on Infinity's website, got em hooked up correctly.

Which wire is positive and which is negative? I have the 4b's and they have the same color wires. I want to make sure there hooked up right!! I have red with black stripe going to + and solid purple to - is that correct? Thanks

[marantzfan]

Which wire is positive and which is negative? I have the 4b's and they have the same color wires. I want to make sure there hooked up right!! I have red with black stripe going to + and solid purple to - is that correct? Thanks

Not sure about the rs4b, but I am pretty sure that if you go to the infinity website and email them asking for info they will send it to you liek they did for me. They replied within an hour, excellent customer service..:thmbsp:

[ji4m]

Which wire is positive and which is negative? I have the 4b's and they have the same color wires. I want to make sure there hooked up right!! I have red with black stripe going to + and solid purple to - is that correct? Thanks

The woofers are wired in series and must play in phase together. Normally, the red wire connects to the + terminal on woofer #1, and the red/black stripe wire connects to the - terminal on woofer #2. The purple wire ties the woofers together, so it connects the -terminal on woofer #1 to the + terminal on woofer #2.

[chameloman72]

the Woofers Are Wired In Series And Must Play In Phase Together. Normally, The Red Wire Connects To The + Terminal On Woofer #1, And The Red/black Stripe Wire Connects To The - Terminal On Woofer #2. The Purple Wire Ties The Woofers Together, So It Connects The -terminal On Woofer #1 To The + Terminal On Woofer #2.

Thanks!! They Were Wired Wrong!!

[VintInfinity]

We require pictures!!! well, at least I do... :thmbsp::smoke:

[Bigears]

Make sure the voice coils are centered before you put the power to 'em. Run them through their travel and listen for rubbing. I find that Infinity woofers are not as easy to center as other makes. Pictures my man!

[marantzfan]

Make sure the voice coils are centered before you put the power to 'em. Run them through their travel and listen for rubbing. I find that Infinity woofers are not as easy to center as other makes. Pictures my man!

Well, I moved the cones back and forth and didn't hear anything. Now being as this was my first time attempting a refoam, maybe I don't know what I should have been listening for. It seemed as if centering these woofers was damn near fool-proof, so now, after your comment I am worried I did something wrong..:sigh:

[marantzfan]

We require pictures!!! well, at least I do... :thmbsp::smoke:

Will do. I only have after photos though..:tears:

[marantzfan]

Well, I FINALLLY got a chance to listen to these. First impressions are very positive. Althought they are not the bass champs that the AR9's are, they definately image better and seem to me like an overall more engaging speaker.

They have a similar open and airy feeling to the Vandersteen 2ce's, but perhaps even a bit more so. I really wasn't expecting them to be so listenable, I guess because I paid so little for them and they looked so rough before I restored them.

These speakers were covered in years of garage dust, dog hair and funk. Also, all of the watkins woofers are a little yellow due to sunlight fading them.

All in all, they cleaned up extremely well and look as good as they sound now. I may have to leave these hooked up to my Kenwood system for a while and give the AR9's a long awaited rest..

BTW, here are a couple of after pics, not the best quality but you get the idea..

[marantzfan]

One other thing..No voicecoil rub on the woofers..Beginners luck perhaps..:D

[VintInfinity]

Great work, now enjoy the music!

[marantzfan]

Now..How would you say that these compare to the Kappa 8's and 9's?:scratch2:

[VintInfinity]

Never heard any of those. I almost got a pair of RS4B but I found the Kappas the day I was going to get the 4B's and went with them instead.

I'm sure they are very similar in sound quality though, a bit less midrange detail with the single 2" dome vs 3" dome and midbass dome. And of course less bass.

[Tedrick]

Now..How would you say that these compare to the Kappa 8's and 9's?:scratch2:
The K9's will definitely hit lower in the bass; the K8's will be on par with the IIIb's in that department. I think the lower mids may be a bit nicer on the 8's and 9's versus the IIIb's, but I'm also inclined to think that these speakers will sound a lot more alike than different.

[Tedrick]

BTW, congrats on a really nice restoration; they're looking mighty good now.

Well, I FINALLLY got a chance to listen to these. First impressions are very positive. Althought they are not the bass champs that the AR9's are, they definately image better and seem to me like an overall more engaging speaker. ...
The IIIb's will never be bass champs, but that's the result of their acoustic suspension design and smaller cabinet volume than the big AR's. However, I can say from personal experience that feeding the IIIb's with a good, high-current amp will maximize the bass they do produce. I used a Carver TFM-25 (225 wpc) amp with my IIIb's for a while many years ago, and then switched to an Adcom GFA-555II (and later a Forte Model 6), and the difference in the bass performance was not small.

[marantzfan]

BTW, congrats on a really nice restoration; they're looking mighty good now.


The IIIb's will never be bass champs, but that's the result of their acoustic suspension design and smaller cabinet volume than the big AR's. However, I can say from personal experience that feeding the IIIb's with a good, high-current amp will maximize the bass they do produce. I used a Carver TFM-25 (225 wpc) amp with my IIIb's for a while many years ago, and then switched to an Adcom GFA-555II (and later a Forte Model 6), and the difference in the bass performance was not small.

Don't get me wrong, they aren't anemic in the LF department either, it's just that the AR9's left large shoes to fill there. Regardless, I love these speakers and really can't beleive how much play time they have gotten in the last couple of days. Compared to almost all speakers I have ever owned, the bass these put out is quite satisfactory actually. Wouldn't mind integrating a sub in with them at some point..Hmmm...That reminds me, my preamp DOES have two outputs...:scratch2:

My Kenwood 700m really makes them sing; I think there's definately some Synergy there. I'm fairly sure the Kenny's a high current design based on the fact that it weighs 70 pounds.

On another note, I had a chance at a pair of RSII's the other week too, but the guy wanted $700 and they had the cone midrange instead of the emims so I passed.

[VintInfinity]

You just did the foam surrounds too, so the bass will improve a bit as they soften up.

A sub certainly would help them, just be sure to get/build a nice one. Preferably a sealed box that is fast and smooth.

[BrocLuno]

Yes, the bass comes in a bit better after say 25~30 hours. Also, placement may be key here. Experiment with room placement?

[marantzfan]

Well. these are still a part of my main system and they have led me to wonder what Infinity has to offer further up the food chain.. Have I been bitten?:scratch2:

[CAK1]

Well. these are still a part of my main system and they have led me to wonder what Infinity has to offer further up the food chain.. Have I been bitten?:scratch2:

It's just begun...start saving the coin now...:thmbsp:

[BobKos]

Well. these are still a part of my main system and they have led me to wonder what Infinity has to offer further up the food chain.. Have I been bitten?:scratch2:

I was browsing eBay a couple years ago - not long after I bought / repaired my RS-4b's. I ran across an ad for an Infinity setup that absolutely blew my mind. It was the same vintage as yours & my speakers. It consisted of a number of components. There were tweeter networks, towers, crossover-like components, and other stuff I'm not remembering right now. I think there was some king of LF reinforcement too. It was all beautiful gear. It sold for over $2K I believe. I can't imagine what it costed new. I wish I could have afforded it at the time I saw the ad. If I saw it tomorrow, I'd buy it immediately.

Yes - you've been bitten.

[marantzfan]

I was browsing eBay a couple years ago - not long after I bought / repaired my RS-4b's. I ran across an ad for an Infinity setup that absolutely blew my mind. It was the same vintage as yours & my speakers. It consisted of a number of components. There were tweeter networks, towers, crossover-like components, and other stuff I'm not remembering right now. I think there was some king of LF reinforcement too. It was all beautiful gear. It sold for over $2K I believe. I can't imagine what it costed new. I wish I could have afforded it at the time I saw the ad. If I saw it tomorrow, I'd buy it immediately.

Yes - you've been bitten.

Sounds like a RSIB.

[gary7]

Nice 4b's. I found a pair Sat. at a Trift store yard sale for $6. They need foam, all woofers, but didn't look beat up. I got them home to see if they would play. one sounded ok, all drivers firing. The other, only sound from the tweeter. Could this be a crossover problem? If so, how can I fix it?