The Infinity RSII came with 2 different midrange magnet sizes???

Coilvoice

Well-Known Member
I just realized after looking on a well known Infinity website that the vintage RSII floor speakers came with 2 different size magnets on the three midrange configuration. :scratch2: The model number on the small magnet ones is 902-0632 and on the huge magnet ones it is 490355. Can anybody shed some light on this? I'm assuming the bigger magnet ones are better, but would like to hear from someone who knows about this. I also am questioning the sponge baffle material that is on the back of mine behind the rear grill which covers the back of the midranges, but doesn't cover the rear firing Emit. I haven't seen this on any other pair thus far. It looks factory to me but I'm just not sure about this either. Anybody? Thanks in advance.
 
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I 'believe' that the center mid should be the driver with the smaller magnet. Since it was used at a different crossover frequency (higher crossover point) than the upper and lower mid-bass drivers, it didn't need a larger magnet, in order to obtain the lower crossover slopes (and the required power handling), that the other mids required. In fact, I've seen pictures of a modded RSII that used a 2" polydome, from a RS IIIA, in place of the standard cone mid, since the middle driver didn't extend into the upper bass like the other two cones did...
 
Not sure if I can help but here goes.
My RSM's have original part #'s 902-0632. This is the same driver as shown in the schematic at the ClassicInfinty site for the RSII.
I recently purchased a pair of #490355 drivers from a set of RSII's. The magnets are MUCH larger but everything else appears to be the same. There's an OLD thread in the archives here talking about that, a search should turn it up.
 
I have a pair of RSII bought new

I just realized after looking on a well known Infinity website that the vintage RSII floor speakers came with 2 different size magnets on the three midrange configuration. :scratch2: The model number on the small magnet ones is 902-0632 and on the huge magnet ones it is 490355. Can anybody shed some light on this? I'm assuming the bigger magnet ones are better, but would like to hear from someone who knows about this. I also am questioning the sponge baffle material that is on the back of mine behind the rear grill which covers the back of the midranges, but doesn't cover the rear firing Emit. I haven't seen this on any other pair thus far. It looks factory to me but I'm just not sure about this either. Anybody? Thanks in advance.
. I do not believe the mids are different, just crossed over differently
I actually never noticed any difference. see also the technical sheet http://www.infinity-classics.de/technik/manuals/RS_II_technical_sheet.pdf . They list a substitute , but I believe original rsII used 3 902-0632
As far as the foam , I have those on mine ,with a cut out
for the rear emit. I think these were added to revised speaker. Mine were purchase Aug 1981
 
if is the link you posted above it refers to RSIII a totally different speaker. possibly one of your mids is not original. It should not be a big deal.
 
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I would like to take a moment and thank everyone for all there help on this matter and it seems like we are close to figuring this one out. :thmbsp:

I have three pair of RSII's at the moment and in pair 1 they have the smaller magnet mids, model number 902-0632 921TNG. This pair did not come with a sponge baffle material behind the mids. This may have been lost... not sure. To be clear, all three mids in this cab have the small magnet 902-0632 version.

Pair 2 has the massive magnet mids model number 490355 511TNG... all three mids in this cab. This pair also has the sponge baffle that hooks to the large magnets to hold it in place along with the rear grill. The cutouts for this baffle are so much larger that when I try to put in in place on Pair 1, it falls off because of the smaller magnets on all three drivers.

Pair 3 are in another state, but I am going to have someone look at them tonight for comparative purposes. I'm thinking that the larger magnet pair with the rear baffle may be a refined pair or something... Not sure. :scratch2:

If you would like to see a picture of this major difference, go to this link and look very closely at all the pictures of the rear of the mids. I believe only one has the large magnets and if I remember correctly it is roughly the middle picture showing the upper half of the cab only from the back. Here is the link to InfinityClassics. Once there, select RSII and look at the pics.

http://www.infinity-classics.de/models/Reference-series-1+b-2-10+A+B-1981-86/index-Reference.htm

Thanks again for the help on this one!
 
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More info

I just wanted to add some more info to paint a better picture.

Large magnet driver model 490355 511TNG measures 101 mm wide X 32 mm thick.

Small magnet driver model 902-0632 921TNG measures 72 mm wide X 28 mm thick.

Huge difference! :jawdrop:
 
I just wanted to add some more info to paint a better picture.

Large magnet driver model 490355 511TNG measures 101 mm wide X 32 mm thick.

Small magnet driver model 902-0632 921TNG measures 72 mm wide X 28 mm thick.

Huge difference! :jawdrop:

What measurement are you quoting here? The actual magnet size?
Side by side comparison here with the 902-0632 and the 490355 shows the same exact measurements for hole to hole (whether straight or diagonal) and the same width measurement. All materials, cone, surround, basket, and dust cap appear to be identical betwen the two models.
The only difference I can see is the much larger magnet structure on the 490355.
It seems Infinty was prone to making changes during model runs that weren't always well documented.
 
mid ranges for my RSII are----bet you can't wait!

i will check my original pair tonight for number
ARE for all six midranges 490355 ! final answer. My speakers have foam covers for midranges with a cut out for emit. purchased new Aug 1981
serial no 90057606 & 900 57607 . I believe prefix 9 indicates modification shipped with foam for back cabinet for midranges.
original pictures in ad brochure did not show foam. These are originals never modified by me.:music::music::music::music::music::music:

I have had them for almost 30 years and would never trade them for anything else!
 
Pair 3 info

What measurement are you quoting here? The actual magnet size?
Side by side comparison here with the 902-0632 and the 490355 shows the same exact measurements for hole to hole (whether straight or diagonal) and the same width measurement. All materials, cone, surround, basket, and dust cap appear to be identical betwen the two models.
The only difference I can see is the much larger magnet structure on the 490355.
It seems Infinty was prone to making changes during model runs that weren't always well documented.

Yes, the measurements provided were for the magnet sizes only. I also found out info on pair 3 that I have, and yes I have too many pairs of this particular model. Pair 3's mids are 490355 J12TNF. I'm still waiting for pics to confirm size, but it sounds like the big ones from a quick description. Fingers crossed. :para: I'm thinking that there are many variations of this speaker, but hard to say considering there vintage.
 
Is it possible the schematic on the Infinty Classics website is incorrect? It clearly shows 2 woofers, 3 midranges and front and rear EMITs. The midrange is specified as the 902-0632, the small magnet 5" driver. With a substitute # of 902-0470.
Another example of Infinity changing things, the EMITs in my RSM's are listed as 902-0484 with a substitute # of 902-5023. BUT---I had an EMIT replaced under warranty with a part # 490126. I have recently purchased 4 more EMIT's part # 490126. Just in case I should need them.
Just pointing this out to illustrate the point that Infinity has substituted drivers other than the original or substitute before.
 
as far as the mids the tech sheet is clearly wrong, mine are an original pair purchased in aug 1981 around the time the RSII first came out.
 
Resurrecting this thread from the deep, dark past...

Just demo'd a pair of RS-IIs today and one speaker had 490813 (x3) with the smaller magnet and the other had 490355 (x3).

Wouldn't you think that all else being the same, the larger magnet version would be more efficient?
 
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Just for more confusion,my RS II's (consecutive serial numbers) that I bought used last year, one speaker has 3 490813 mids, the other has 3 902-0632 mids (all are small magnets) I have no idea if one or the other has been modified since new.
Last year, in a flash of brilliance, and knowing the middle midrange carries a wider frequency range than the top and bottom mids, I thought what the heck, I'll use a pair of 490355 mids from my spare parts pile (large magnets) for the middle mids. Except the 490355 mids I have only have two terminals/tabs (top and bottom) they do not have the tabs that protrude straight out (to the side) and which would require no wiring changes (like length or pattern) to hook to the existing wiring.

Earlier today I saw a pair of 10" woofers on ebay, 902-5079...after some research I passed as I could not determine if they were a proper replacement as those are not among the normally mentioned RS II woofer replacement model numbers.
Maybe someone here bought them.
 
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if they are ten inch infinitys with poly plastic cone with intergrated dust cap they should be ok .
that version was used on RSII and other infinitys. the entire cone with dust cap are clear.
 
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