Infinity SM-122 Studio Monitor

[BrocLuno]

Cabinet mods are about playing your speakers pretty loud and running you finger tips over the surfaces of the cabs. If you feel the cab flexing and "buzzing" under your finger tips, they need to be reinforced there. A cheap and easy way is to install a 1x1 pine brace across the cab there with good glue on each end. I use PL400 as it allows slight undercut lengths for easy fit and the glue expands slightly to fill the gap. If it's from front to back you can insert some black sheet rock screws into the ends of the brace. They won't show because of the grills. Side to side, you have to determine if a black screw head will bother you esthetically?

Recapping the X-Overs means pulling the old caps and installing new poly caps. Since the poly's are much bigger, you'll have to rethink the mounting positions, but that's usually not a big deal

 

[paiste2002]

sometimes "pimping" is the answer

alot of people waste alot of time trying to fix great or even average speakers with some deficiencies.for the sm 122s(or the like) it appears that the woofer becomes the main issue.it also seems that people want to keep things original.truth is, sometimes original isnt better.i took a pair of sm 120s and rather than fixing the original woofers went a step further. i took a pair of rockford fosgate punch(p1's) and fit them in place of the outdated, rotted cones. being that the hole space was 11.5 inches, it involved cutting the hole a quarter of an inch further(this was done by a professional wood saw, very carefully)with new screw holes and new allen wrench type screws supporting the speaker. this was done at the suggestion of a car/home audio expert of at least 25 years. the new speakers have much more wattage capeability(about 4 times as much)as well as butyl rubber surrounds that wont rot in our life time.my original worry was the impedence difference. he assured me the rockfords could handle many different impedence........................they can...and safely too! now the speakers have more balls than ever. to remove the over boomieness that these cabinets always had(regardless of the woofer brand, wattage, ect) i bought cheap pillows from k-mart, and used the stuffing to dampen things. these speakers, which most wouldnt rate above a 6 (on a scale of 1-10), are now a true 8.5!!!!!!! ive had audiophiles listen to them and all agreed that the transformation was dramatic. in my system,a 2 channel vintage yamaha r-70 runs the show at 80 watts per channel(very reasonable power), the sm120s are in back and a pair of polk rt155i are in front. the mellowness of the polks vs. the sharp sound from the infinities has created an amazingly high end sound from generally "middle of the road" sources. maybe one day i'll be as rich as rockefellor and get lynn or b+w with a mcintosh amp, but for now, i will be pimping my equipment within the guidelines of experts....thank you for listening to me babble on and hope i helped out on some issues......................................p.s. dont bother looking for the yamaha r-70 amp because any in really decent condition are collectors items and wont be on ebay(or anywhere else for that matter)good luck in the pursuit of great sound all, bye.

 

[goat67]

alot of people waste alot of time trying to fix great or even average speakers with some deficiencies.for the sm 122s(or the like) it appears that the woofer becomes the main issue.it also seems that people want to keep things original.truth is, sometimes original isnt better.i took a pair of sm 120s and rather than fixing the original woofers went a step further. i took a pair of rockford fosgate punch(p1's) and fit them in place of the outdated, rotted cones. being that the hole space was 11.5 inches, it involved cutting the hole a quarter of an inch further(this was done by a professional wood saw, very carefully)with new screw holes and new allen wrench type screws supporting the speaker. this was done at the suggestion of a car/home audio expert of at least 25 years. the new speakers have much more wattage capeability(about 4 times as much)as well as butyl rubber surrounds that wont rot in our life time.my original worry was the impedence difference. he assured me the rockfords could handle many different impedence........................they can...and safely too! now the speakers have more balls than ever. to remove the over boomieness that these cabinets always had(regardless of the woofer brand, wattage, ect) i bought cheap pillows from k-mart, and used the stuffing to dampen things. these speakers, which most wouldnt rate above a 6 (on a scale of 1-10), are now a true 8.5!!!!!!! ive had audiophiles listen to them and all agreed that the transformation was dramatic. in my system,a 2 channel vintage yamaha r-70 runs the show at 80 watts per channel(very reasonable power), the sm120s are in back and a pair of polk rt155i are in front. the mellowness of the polks vs. the sharp sound from the infinities has created an amazingly high end sound from generally "middle of the road" sources. maybe one day i'll be as rich as rockefellor and get lynn or b+w with a mcintosh amp, but for now, i will be pimping my equipment within the guidelines of experts....thank you for listening to me babble on and hope i helped out on some issues......................................p.s. dont bother looking for the yamaha r-70 amp because any in really decent condition are collectors items and wont be on ebay(or anywhere else for that matter)good luck in the pursuit of great sound all, bye.

First off
Welcome to AK
Interesting thoughts

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[montysano]

Maybe it's a matter of what they're paired with. I picked up a pair of mint SM122s last weekend as a quick and dirty replacement for my KEF 104/2s. The KEFs had a hard life and were sounding pretty dull; a bad rattle in the low end was the last straw. I had been especially frustrated at the lack of brightness. My receiver is a Luxman R-1070, which tends toward warm rather than bright. I use a Grado cart, which has a very round sound.

I've only had a few days to listen, but I'm fine with the SM122s so far. I just recently bought a Bellari VP129 tube phono preamp, so the mids are much more out front (esp. after I pulled the Chinese 12AX7 and replaced it with an EI brand). Are the mids too much out front? I dunno, but I'm loving hearing 'em. For a while after I got the Bellari, I just listened using its headphone output because it was so superior to my speakers, but now what I'm hearing in the speakers is much closer to the Bellari's headphone output. Plus: the Infinitys will rock. As wonderfully refined as the KEFs were, they just never thrilled me with U2 or the Police cranked up loud.

BTW: the Bellari is IMHO quite the deal for $200.00. And it's red. :thmbsp:

 

[blownsi]

For the experience I would grab them. They are great for the basement. Perfect for listening to while shooting pool, etc.

 

[bobrown14]

SM series

Well I have 2 pairs of SM-255's - the largest of the SM series. They sound great as fronts hooked up to my surround sound in my living room and the other set is hooked up in my dining room to a Sansui 771 receiver. These were the first speakers I bought when I got into vintage gear. They made their way from the listening room to the living room when I replaced them with better speakers (EV Sentry III's). They (255's)sound pretty good and the rock n roll speaker thing pretty much sums it up. The 255's are mighty fine for home theater, but for more critical listening ... well I don't use them for that. The 255's don't need any upgrades that I know of for box bracing or the like. They do sound good matched with my other Infinity surround sound gear (sub, center and rears). Why you ask would I need a sub with this speaker: well to "FEEL" the bass! Not bad could I do better? Yup but it would cost me a bunch more. SM series are good to get started on and will probably lead you into the never ending elusive trail to audio nirvana. My advice would be grab em for $30, listen for a while and trade up when you get components that you know should sound better but don't.

You might get lucky with a good match with the pre/amp but that might take allot of research. I'm not surprised tho that someone mentioned Yamaha gear sounding good. My experience with Yamaha is the sound is fairly sterile compared to Sansui gear driving them. With all that sensitivity in the Infinities that doesn't surprise me. I have tried out Yammys but what I have is not hooked up now but it did sound good with my SM-255's. Probably any somewhat neutral sounding pre/amp should do well with those speakers, anything with a little "color" maybe not so good. Yammys = neutral (benign almost); Sansui = a little more warm tube like sound, Technics pro gear = somewhat colored a little warn but not as much as Sansui.
My .02 FWIW. Flame suit on.....

Cheers,

Bob Brown

 

[cmb3366]

There are alot of speakers that will blow the Infinity Studio Monitor series out of the water. At the same time, these speakers are far from junk, and they are very good at certain things. Rock music for example.

I'm listening to Genesis' Selling England By The Pound album right now as I type on a pair of $800 Klipsch Reference 35's, and I'm debating whether or not I expend the time and effort to unplug them, and setup my SM-120's. The Klipsch, as expensive and fancy as they may be, suck on rock music. They just plain dont have the mids and bass that the Infinities do, they just dont sound very dynamic on rock and roll. Now, when my L100 T3's are done being refoamed (6 days), the Infinity's wont see the light of day except for outdoor parties, but that is not a knock on the Infinity's, just acknowledgement that they can be outdone by much more expensive speakers. In the ~100 dollar range, I think SM's are one of the best buys going for the rock listener on a budget.

 

[Nacon]

In my SM-152, it was modified a little for bracing the cabinet , I have a good match with the pre/amp , CD of Soundcraftsmen that little more warm tube like sound, now it perform the Jazz and vocal, Symphony specially fantastic in 3 ranges.
I know Studio monitor (SM) speaker will be designed to produce relatively flat (linear) phase and frequency responses. In other words, there will be no emphasis or de-emphasis of particular frequencies so that the loudspeaker gives an accurate reproduction of the tonal qualities of the source audio ("uncolored" or "transparent" are synonyms), and there will be no relative phase shift of particular frequencies meaning no distortion in sound stage perspective for stereo recordings.
If you want Infinity SM sound better than original you should brace the cabinet, put it on a stable feet, away from floor it give much better bass response. You also can adjust the reflex port by reduce the open to prevent the booming.
Some my friends come to hear SM-152 and they said I am using horns for mid range, due to Saxophone, Trumpet sound are better than their mid horn.

 

[Yamahalic]

My Recent Infinity SM-122 Woofer Refoam Experience

:tears: Sadly, the woofer foam surrounds on my SM-122s just disintegrated a few months ago. I decided to try to refoam them myself, but it was a bit of an ordeal as I was soon to find out. To begin, I purchased the 12" Infinity Speaker Repair Foam Re-edge Kit from Orange County (OC) Speaker. Here is their on-line advertisement information for this kit (I copy pasted this as of 01/31/09)...
---
This is a brand new - fresh stock CORRECT Infinity 12" foam surround Re-Edge Kit. This kit is not the generic "one size fits all" like others sell...
---
:nono: Well, the above was NOT 100% correct information as I was soon to find out. I discovered that the Infinity 12" woofer is not quite as large in some respects as a typical 12" woofer on the market. For example, the SM-122 12" woofer fits into a 10.5" hole, but most aftermarket examples fit into an 11" hole. Well the same issue occurred with the OC Speaker foam surrounds...THEY WERE TOO LARGE! The ID was too large to properly fit onto the woofer cones, and the OD was too large to fit within the woofer installation finisher ring (so much for "Correct" and "not generic"). After much on-line investigation, the only proper thing about these surrounds was that the inside edge angles downward, which is correct to mount to the backside of the woofer cones. I suspect many people might simply glue the insides of the foam to the top surface of the cone, which I have read is not advisable for these speaker cone types. P.S. gluing to the inside is VERY difficult without removing the cones from the speaker. Anyway, I do not know how to remove the cones to more easily glue onto the backside of the cones, so I decided to have the work done by OC Speaker.

I am happy to report that I received the speakers back, and they look and sound great! NOTE that a segment of the foam surrounds had to be cut out to effectively make the foam diameter smaller. Then the two open ends were glued together (one end overlapping the other) to fabricate a proper foam surround for this application. Also note that the dust cap may also be replaced (I did not ask for this, but it was done anyway, so keep in mind you will lose the original dust cap with the Infinity logo on it unless you specify otherwise).

I initially looked around for a bolt-in/drop-in replacement woofer of similar ohm rating (approx. 3.6-4.0 ohms), and I am convinced that a new woofer as described does not exist. A few emails to Infinity/Harmon-Kardon parts group were absolutely useless, and of no help whatsoever! I wanted to find out the specs of the original woofer, more specifically the upper end extension of the operating frequency range, but I could not find this info. So if you decide to select a new replacement 12' woofer, then cabinet mods will most likely be needed (most likely enlarging the cabinet opening, and drilling new installation holes). You will also lose the use of the installation finisher ring as well if that matters to you.

BTW, upon removal of the woofers, I learned of the extent of Infinity's "cost cutting" efforts on the SM line...cheap wiring, no cabinet bracing, no stuffing, and 3/4" cabinet construction (I think 1" MDF may be more appropriate for a speaker this large). Oh well, now that I have the woofers repaired, maybe I can improve these speakers by adding some stuffing, solder in better wires, and add some bracing to minimize some of the cabinet resonances (yeah, I know there they are there, but not too noticable when listening to impactful rock music).

I hope my experiences may help others who wish to keep their Infinity SM speakers going (as I did). IMHO, a woofer speaker refoam (by a pro) may be a good investment to add some life to these speakers.

 

[drail]

Yamahalic, if it was necessary to cut down the surrounds to fit then you were supplied with the wrong surround. Infinity did produce some non standard sizes but there are correct replacement surrounds available. I have never heard of having to cut one to make it fit.

 

[Yamahalic]

Infinity 12" Woofer Surrounds

I would be surprised if any manufacturer actually made a surround mold form to produce a surround for my odd sized (under sized) 12" woofer. In my case, this is what I thought I was purchasing from OC Speaker, but it was not the case. So, one cannot believe what one is told by a vendor without exact measurements confirmation in advance (lesson learned).

 

[V'ger]

I would be surprised if any manufacturer actually made a surround mold form to produce a surround for my odd sized (under sized) 12" woofer. In my case, this is what I thought I was purchasing from OC Speaker, but it was not the case. So, one cannot believe what one is told by a vendor without exact measurements confirmation in advance (lesson learned).

With some foam, you can buy the closest undersize and then stretch them. This increases the ID and OD, so you have to constantly check both against the cone and basket frame until you get it just right.

I have the same problem with the 902-4585 5 inch speaker which requires a 4.75 inch OD foam. Only 4.5 inch and 5 inch are available. So I took the 4.5 inch and stretched it until it was the right size.

 

[RickeyM]

The above pic is the original x-o of my Sterling 2004's. If the x-o on the Infinity SM series looks anything like this, then it definately is part of the reason they sound like they do. I redid my x-o's using better components and guess what? Polycell tweeter realy do sound good.

I used Obbligato "oil" caps and "air-core" inductors on the tweeters. The original x-o uses an inline resistor to raise the ohms of the tweeter and drop it's output. I used a real L-pad network with audio grade resistors. These relatively simple upgrades made the speakers much more listenable. None of the components I used were expensive, but they perform way, way, way better than the "lowest bidder" stuff Infinity (Harmon Int.) put in there in the first place.

As someone already pointed out, these aren't high-end speakers, but they can sound good with a little bit of work.

 

[Yamahalic]

More Infinity SM-122 Notes

In my case, I have never had a problem with the x-o. I like the high and mid frequency adjustability/knobs on these speakers for added fine tuning of the sound. I also choose to apply some equalization to the signal to further "enhance" the Infinity SM-122 sound. To me, a "U" shaped curve on an equalizer (or turning up both treble and bass) really works well with these speakers (I also sometimes listen to Yamaha's DSP processing as well).

In my past, I have also owned the infamous Yamaha NS10M "studio monitor" speakers, and I had the same issue (i.e., I didn't much care for the sound with no "enhancement"). I have read much about the need for "uncolored" monitor speakers in studios, but I consider these types of speakers to be rather flat and boring (read: no soul). So, for me, I am happy after tuning these speakers for my room (large) and music/theater tastes.

I once listened to very similar/competitive Cerwin-Vega speakers (3-way towers, 12" woofers), and to me their sound was MUCH warmer, with rich bass with somewhat muted highs. I liked the Infinity's better at the time, so this is why I ended up with them.

 

[TUBEDatomic4]

I owned a pair of Infinity SM-125's and was disappointed with them at first but with some playing got some enjoyable tones to flow. I will say the cabinet is in need of reinforcements! I think the components themselves could be great assuming the cabinet was more solid. I also feel that a quality recap on the x-over would yield some good improvements. I never actually got into modifying them but simply tried many components with them. Is it worth all this.... maybe. If your new into the 2 channel audio world they are just fine. I personally would run a small SET 10-30 watt integrated amplifier to them and call it a day. No need for big SS power at all!

Oh and I've seen many refoams for them that were the correct ID and OD. I wonder why the above mentioned foams had to be cut to correct size. I know this because I was going to order a new set of foams for later while I owned mine. I ended up selling them so it became unnecessary at that point.

I'd buy them and play. Even at this stage of the game, I'd do it just for fun. Who cares, have fun, play music and enjoy!

Thanks.

 

[Silvy]

I had SM 150s and to be honest...I REALLY miss them. Should have never sold them. I think that these speakers really come alive with the right amp (A good strong amp because they drop down under 3 ohms on the frequency curve) and in the right sized room. I have run some very nice speakers in the same location and they just DONT land the sound that the SMs kicked out. I will say that I listen to Classic Rock and Jazz more than anything else and they were Superb at delivering both. I think that there are a lot of bad experiences with these speakers because you really need to get them in the right location and the room needs to be BIG enough. I have spare parts for these still sitting in my parts bin...maybe I'll build some new cabinets ;-)

 

[BrocLuno]

This little SM thread is really interesting. These are not speakers I would ever fear of loosing value with hot-rods and mods. It's great to see what folks are doing out there in the lesser reaches of Infinity land. I may grab a pair if they come along (none currently in my collection) and see what I can do with cross-over mods

 

[Yamahalic]

For reference, the Infinity SM-122 12" woofers "correct" looking surrounds measurements are as follows:

- speaker cone edge OD = 9" (ideal measure also for surround bulge ID)
- surround bulge OD = 10.125"~10.25"...10.5" max. (Infinity finisher/gasket ring has an ID of 10.5")

As noted in this thread, I also was surprised that my surrounds had to be cut and glued to properly fit onto my woofers, but then again OC Speaker is one of the most well known speaker repair companies around (a great reputation), and an authorized Infinity repair shop. Infinity SM... owners need not contact Infinity parts dept as they were completely useless during my couple of attempts.

In any case, the repaired woofers sound great, and I can delay a new mains purchase to another day. I do listen to rock, as noted by many other happy Infinity SM... owners, and also many other forms of music with impactful bass (80's music with synth bass, Jazz, Bach, etc.). Of all the other speaker types I have heard, my tastes lean toward 3-way speakers with a woofer that can move some air (such as the SM-122s). I use these also as my mains for my Home Theater, later purchasing an Energy Take FPS for my center (2-way, 2 x 4.5" woofers). The Energy is great for HT center duty, but it would not work well as a replacement for the SM-122s (I tried it just out of curiosity).

 

[Yamahalic]

I owned a pair of Infinity SM-125's...Oh and I've seen many refoams for them that were the correct ID and OD. I wonder why the above mentioned foams had to be cut to correct size.

I think the issue is if you want to refoam the 12" Infinity SM series woofers in the "original" way (with the inside foam glued to the underside of the cone), then a perfect fit is required. This is difficult because these 12" woofers are smaller than the norm, the cones are 9" in diameter, and the speakers fit into a 10.5" hole (most 12" woofers require around an 11" hole). The ID of the foams roll area would need to be exactly 9", and this would be a rare find indeed. So, I think most refoams of these are done with the inside foam glued to the top of the cone, thus hiding the oversized foam specs. I wanted mine to look original.

Perhaps the Infinity 12" SM series woofer at the time was actually a metric driver from Asia? This might explain the wierd dims.

 

[Rjenglish]

There is a pair of mint Sm-122's for sale here in my area. The asking price is $200. The guy is also selling a pair of Cerwin-vega dx-7 for $200. or both for $350. Are they worth that much? Which one is a better speaker?