RS III A's

[bluescat]

I have had a perfectly fine sounding pair of RSIIIA's for 3 or 4 years now, couldn't be happier with them,... but....when I bought them, they had been refoamed and recapped, using this schematic. http://infinity-classics.de/technik/manuals/RS_IIIA_technical_sheet.pdf.
Later I saw the hand drawn schematic in this thread:
http://www.audiokarma.org/forums/index.php?threads/rsiiia-crossover-assistance-please.622434/
and noticed that a couple of the midrange caps were different 16.5uf vs 19uf. Although I am perfectly satisfied with the sound, as they are, I can't help but wonder if I might like them better if I changed the midrange cap values from 16.5uf to 19uf. Any of you speaker builders have any thoughts on what the change in sound would be if I added 3.5uf caps to the 16.5uf. From what I can gather, the schematic used to recap my speakers are actually for RSIIIB's (not A's), and since they were produced later(IIIB's) and nothing else was changed, maybe the way they are capped now may actually be better than the original (IIIA's)......anybody confused yet.....if not I'll try harder..Thanks

 

[StimpyWan]

If my calculations are correct, it would lower the dome mid high pass crossover point from around 600Hz, to about 520Hz. With changing only the 1 cap value, the woofer low pass wouldn't shift. So, the increase in cap value would result in a bit more of an overlap in frequency, between the woofer and mid. It might slightly change dispersion. A touch more mids? Would it be audible? Not sure. Buy a cheap NPE and try it. If you like the change, leave it in. If not, cut it back out. If it makes a nice difference, use a poly. Regardless, have fun!

 

[srb02]

I bought a spare pair of crossovers for my RSIII/a's.
So the crossovers in the speakers have one setup, the spare crossovers have another "different" setup,
and the schematics you posted are different than both of the first two. Go figure.
It was explained to me, that Infinity changed components on the fly, when they changed batches of drivers w/ different parameters.


my two cents Stu

 

[bluescat]

I bought a spare pair of crossovers for my RSIII/a's.
So the crossovers in the speakers have one setup, the spare crossovers have another "different" setup,
and the schematics you posted are different than both of the first two. Go figure.
It was explained to me, that Infinity changed components on the fly, when they changed batches of drivers w/ different parameters.
my two cents Stu

"Crazy", I guess you can just throw any old caps in there, and still call it an RSIIIA, Doesn't make alot of sense to me, but what the hell do I know. Probably ought to just enjoy what I have. Damn, I hate when winter hits, I leave things alone when the weather is nice.

 

[bluescat]

StimpyWan, thanks for taking time to do the calcs. Like I stated above, I probably should leave well enough alone. BTW, I traded off those 6's we talked about earlier in the year. I needed an equalizer for the Bose 901's in my pole barn, and traded the Infinities for a trashed pair with a good eq.

 

[goodolpg]

There have been many cases of actual crossover build not matching the "official" schematics.
Sometimes they were official factory updates, sometimes possibly it was just using what was available at the time of manufacture.
When ordering parts for a recap it is probably wise to check the values installed (provided they are OEM crossovers) in the speakers being recapped prior to ordering.

 

[bluescat]

All of this brings us to an obvious question (at least it is obvious to me).....Why spend the money on a recap, unless the caps are so far out of spec as to cause obvious distortion? Almost every post you read regarding buying used speakers, suggests recapping, but why, if you don't even know what the manufacturer intended? A 40 year old speaker could have been recapped by an experimenter somewhere along the way, and if you just replace the caps with like caps, you will never know what that speaker should sound like. Alternatively, regarding Infinity, you could follow their published schematics, and it would still be wrong. I think I need a drink!!

 

[StimpyWan]

StimpyWan, thanks for taking time to do the calcs. Like I stated above, I probably should leave well enough alone. BTW, I traded off those 6's we talked about earlier in the year. I needed an equalizer for the Bose 901's in my pole barn, and traded the Infinities for a trashed pair with a good eq.

Well with already having a set of IIIA's, why not trade the 6's? But Bose??? Come on...! Though, I shouldn't complain; they're in the Barn...!!!

 

[bluescat]

Well with already having a set of IIIA's, why not trade the 6's? But Bose??? Come on...! Though, I shouldn't complain; they're in the Barn...!!!

I hear ya, it almost didn't make any sense to me either, but I got the original 901's free, just needed re-foamed and an eq. Since the 6's still needed fixed and I didn't want to put anymore money in the 901's, I traded on a whim.(as is everything I do). Actually, I get a lot of favorable comments on the 901's, but I still don't think I would want them in my house.

 

[goodolpg]

All of this brings us to an obvious question (at least it is obvious to me).....Why spend the money on a recap, unless the caps are so far out of spec as to cause obvious distortion? Almost every post you read regarding buying used speakers, suggests recapping, but why, if you don't even know what the manufacturer intended? A 40 year old speaker could have been recapped by an experimenter somewhere along the way, and if you just replace the caps with like caps, you will never know what that speaker should sound like. Alternatively, regarding Infinity, you could follow their published schematics, and it would still be wrong. I think I need a drink!!

Yup, it can be confusing for sure.
As well as how they reused the same or similar model numbers during different series of speakers.

 

[StimpyWan]

I hear ya, it almost didn't make any sense to me either, but I got the original 901's free, just needed re-foamed and an eq. Since the 6's still needed fixed and I didn't want to put anymore money in the 901's, I traded on a whim.(as is everything I do). Actually, I get a lot of favorable comments on the 901's, but I still don't think I would want them in my house.

I shouldn't pick on your 901's, as I've never even heard them (I'd like to hear a pair some day). Plus, I know Amar Bose was a very smart man. He wouldn't design junk. Lot's of innovator's like him, in the audio world. A shame though, as there are fewer and fewer left.

 

[bluescat]

I shouldn't pick on your 901's, as I've never even heard them (I'd like to hear a pair some day). Plus, I know Amar Bose was a very smart man. He wouldn't design junk. Lot's of innovator's like him, in the audio world. A shame though, as there are fewer and fewer left.

I auditioned them in a showroom back in the 70's and didn't like them then. Now that I am old and my hearing is not that good, they sound ok to me, in the right setting, like my barn, or maybe some other non critical listening area, like a bar.

 

[slimpikkins]

My older brother had a pair (901's) hanging in the corners of his room. They could really knock the dust off the ceiling. Thought they were great at the time, fun rock and roll speaker. Mother did not like them much...

 

[bluescat]

My older brother had a pair (901's) hanging in the corners of his room. They could really knock the dust off the ceiling. Thought they were great at the time, fun rock and roll speaker. Mother did not like them much...

They will do "that",(knock the dust off) the bass is great. I like to have them on when I am in the driveway working on something, and not in the confines of the building. You would think there is a live band in there. Get inside with them though, and I find myself constantly fiddling with the volume. Actually they are perfect for my application, hanging from the ceiling, out of the way, and I can hear them from anywhere on my property. Good thing I have no neighbors close by!!