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Infinity SM 112's

jmitchell59

jmitchell59

Member
Howdy! I just got home with a set of Infinity SM-112 3 way speakers, that I found at the local SA for $20. My experience with Infinity has mainly been with their smaller speakers (like my RS 1000's), so I don't know much about these. They do have foam rot on the woofers, and was thinking of sending them out to get redone. Worth the $$ or should I attemp to do myself? I was very suprprised when I pulled the woofers and saw that there was NO damping material in them! Would a previous owner have taken it out, or were they just trying to save .49 cents? Anyway, any info on these would be appeciated.
 
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I have a pair of the larger Infinity SM125's....you can buy the surrounds on Ebay for about $15.00.....I'm going to replace the 12" woofers with Dual 12" woofers from Walmart....$30 each...saves the hassle of foaming myself...and sending them out to get done!! It's a quicker fix!!! I have seen your SM112's go for around $100 in mint shape with good woofers...mine are sold for about $25 more also!
No insulation in mine also.... when I bought them for $20.00....
 
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Cabinet in that SM series is the weakest part of the speaker. Adding some bracing will help.

I think the high sensitivity (like 100dB) is in part because that empty box.

That Infinity series is not very appreciated, so I wouldn't spend big $$$ in those. I would try a DIY refoam.

I wouldn't replace the original driver. It's always better to repair it. Crossovers and the other drivers are calculated for that specific woofer. It's almost sure a replacement woofer won't be as efficient as the original. I'm sure it will sound at lower volume than the other drivers.
 
Put some 2 x 2 for internal bracing, front to back, side to side. I would add a little insulation to break up internal reflections, refoam the woofers. They are fine for what they are intended to be....no a high point in Infinity's known work!
DC
 
:yes: I agree, they sound very good for what they are intended. Actually I became an Infinity fan after listening to a pair of Sm125.

you can add some foam or carpet inside the cabinet. But just recycle, don't spend too much, find some insulation around :)

Bracing the cabinet requires some skill, but actually is just glue some wood pieces holding the front to the back and one side to the other. It can be tricky to cut the pieces at the appropiate lenght. But if you want to do it later, you can ask at the DIY forum. Refoam first, insulate the cabinet, recap the crossover, brace later :)
 
OK, I was thinking of some Gorilla glue and 2x2's wouldn't be a big deal, but is recapping the crossover worth the effort, or is it just for the sake of longevity?
 
replacing old electrolytics always worth the effort... It's small money, and you'll be sure the speakers are working as they where designed. Just get some film caps, I would'n worry about "brands". Just any film cap will do the job.
 
i had a pair years ago .

with the mods mentioned , they will improve - but don't expect too much .

the cabs are poorly made- hollow , thin particleboard w/ no bracing or even cleats .

i also agree that no insulation = more spl/w , which would've been the selling point
for this line ( likely intended to compete w/ cerwin vegas of the late 1980's/early90s)

they might've done much better to copy the cv's cabs(TANKS!) , instead of the mid and tweeter configuration/x-over points . just with a lower woofer/mid crossover
freq.(200-300) , an actual midbass , and a decent tweeter- who knows what they might've been .....
 
Get a tube of liquid nails (better yet PL construction adhesive or even white glue, do NOT use gorilla glue as the expansion is undesirable) and lay a bead along all inside joints including and especially the ones for the soundboard. After you lay the bead follow it with your finger to force it into the cracks if possible.
This is probably all the strengthening the enclosure needs, if you feel happy about this you can add a few dowels or the like at strategic locations or even a few corner blocks but those are only a must for larger subwoofers at high power and excursion levels. If I'm buildng a box and that's in the mix I don't fook around and bracket metal angle extrusion in from the get go, especially if it's multiple subs in one box, the bracing can go between them. The reason for extrusion over wood is it's unquestionably strong and removes little volume from the enclosure.
I concurr about NOT repacing any drivers unless absolutely necesssary. Just because it's a 12" driver doesn't mean its characteristics are appropriate.
Funny enough at low power levels cheap drivers usually have more output, because they have lower moving mass than high quality drivers made for higher power handling.
Lots of people used to replace the $10 paper speakers in their stock car system and the saleperson talks them into a pair of $200 coaxials and they sounded WORSE than the stock ones. That's because the stock sysyem had just 8 watts RMS or so, the coaxials needed an honest 50 watts or more just to get going.
 
I'd refoam them, listen to them briefly so you know why they aren't well respected, then sell them to someone that likes Cerwin Vegas, but thinks these are more "Audiophile" because of the name, even though they actually aren't.
 
I wouldn't buy any more Infinity's unless they were "Real Stuff" from the 1970's or early 80's.....after that they went down hill....Now everything is generic Made in China!!! Same with alot of the new JBL stuff!
 
Well, I called PE, got two new woofers, braced the cabs up butgood, and put in damping. Not great, but not that bad, either. Seems to have tightened the bass up, overall spl is down, but no big deal.
 
Why didn't you just refoam the original woofers with new surrounds? Those would have to sound better in those cabinets I would think.
 
avguytx said:
Why didn't you just refoam the original woofers with new surrounds? Those would have to sound better in those cabinets I would think.
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+1... with exceptions, you should always stick with the original drivers - even if they're not so great in the first place.
 
Teradacto58 said:
I wouldn't buy any more Infinity's unless they were "Real Stuff" from the 1970's or early 80's.....after that they went down hill....Now everything is generic Made in China!!! Same with alot of the new JBL stuff!
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Man, you have plenty of terrible advice for this thread don't you?

Are you saying the Infinity Renaissance aren't worthy of the infinity name and are crap? What about the later Kappas?

You also suggest using random dual brand woofers that are the wrong impedance as drop in replacements. :thumbsdn:

To the OP, the SM series infinities I had are the worst ones I have owned. I sold them post haste after a refoam. Sorry if it sounds harsh, just being honest.
 
240sx4u said:
Man, you have plenty of terrible advice for this thread don't you?

Are you saying the Infinity Renaissance aren't worthy of the infinity name and are crap? What about the later Kappas?

You also suggest using random dual brand woofers that are the wrong impedance as drop in replacements. :thumbsdn:

To the OP, the SM series infinities I had are the worst ones I have owned. I sold them post haste after a refoam. Sorry if it sounds harsh, just being honest.
Click to expand...
+1. And let's not forget the Prelude MTS's, which were rated as Class A-Full Range in Stereophile just a couple of years ago and rate as one of my top 5 or 6 listening experiences of all time :music:. Heck, the current Primus line of budget speakers have gotten rave reviews in the magazines and the 'net, and have even developed a bit of a cult following with the mini-watt tube folks. Yes, Infinity has made some dogs since the Harman takeover, but they've also made some gems.

To the OP, if the stock woofers are in good condition except for the surrounds, send the replacement woofers back for a refund. Refoaming the stock woofers is cheaper, will be a great learning experience, and will probably sound better than the replacements to boot.
 
batvette said:
Get a tube of liquid nails (better yet PL construction adhesive or even white glue, do NOT use gorilla glue as the expansion is undesirable) and lay a bead along all inside joints including and especially the ones for the soundboard. After you lay the bead follow it with your finger to force it into the cracks if possible.
This is probably all the strengthening the enclosure needs, if you feel happy about this you can add a few dowels or the like at strategic locations...
Click to expand...

I did this very same thing to a pair of Infinity Sterling series speakers and was amazed at how much it tightened up the cabs. The Sterling series was similar to the SM series, just not geared for max SPL. I used some inexpensive oil-in-paper caps and Dayton resistors on the tweeters and they were a bit more listenable.

As others have said, refoam the original woofers.
 
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