RSlllb -about to begin a restore/mod project with some questions

spaceysounds

spaceysounds

New Member
hello all
this is my second pair of Infinitys, upgrading from a set of RSb. the RS3b that i got are in great shape, cabinets, grills are perfect, diffusion foam is all together, all original parts. the foam surrounds need to be replaced.
so i ordered all new foam surrounds, caps, potentiometers, binding posts, wire, etc.
so far i have tested all the drivers with a mulitmeter (all good). i removed the woofers and removed all the old foam and glue (2 +hours each driver!). i added a bit of Dynamat to the backs of the baskets.
pretty sure i've read through all the 'RS3b, RSiiib, and RSlllb' searches on here and learned alot so far.

i have a few questions about things i can do next while I'm waiting for the parts to arrive.

a) should i reseal around the inner cabinet edges with silicone?
b) is it a good idea to add some acoustic foam to the inside walls, if so what size? (3/4" high density?) and glue it to which walls? (If i add foam do i keep the polyfill inside or use them together?
c) should i add some internal bracing front to back or glue some ribs to any of the sides? if so where in the cabinets and what size? (block off the EMIT and Polydomes maybe?) (i have a sheet of 3/4" MDF)
d) is it worthwhile to glue some felt or foam to the inside of the woofer baskets?

i want to make them as good as possible the first time so i don't have to worry about it in the near future, however i don't want to go overboard and kill the sound..

thanks for you help!
 

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Sounds like you have a plan. For bracing a "t" between the woofers, front to back and side to side and maybe another one between the top woofer and midrange. Those cabinets were made pretty sound but I guess you could caulk the inside. If you were keeping these forever than maybe even dynamat them but that stuff gets $$ and I'm not sure how much benefit it would be as I have never done it.

Be sure to take some pics and document your progress here.
Jim
 
I "upgraded" a pair of Qb by replacing the yellow film caps. It ruined the high end so much that I ended up fishing the old caps out of the trash and re-installing them. YMMV
 
Unless you are itching for a project, I'd just change out the small electrolytics and make sure they're wired correctly.
They sound good stock.
If you must, try front to back 1"X2"s at the woofer screw holes(one woofer is a no go with the crossover in the way) however that cabinet didn't seem to have too much resonance vibration.
Picture 1424.jpg
 
Congrats on your new speakers, that's a pretty big move up ! Your cabs look nice and those woofers too. All I can say is I've never heard them but looks like your on the right track.
 
slimpikkins said:
Sounds like you have a plan. For bracing a "t" between the woofers, front to back and side to side and maybe another one between the top woofer and midrange. Those cabinets were made pretty sound but I guess you could caulk the inside. If you were keeping these forever than maybe even dynamat them but that stuff gets $$ and I'm not sure how much benefit it would be as I have never done it.

Be sure to take some pics and document your progress here.
Jim
Click to expand...
yeah that Dyanamat is not cheap!
 
chef free said:
I "upgraded" a pair of Qb by replacing the yellow film caps. It ruined the high end so much that I ended up fishing the old caps out of the trash and re-installing them. YMMV
Click to expand...
yikes okay I'll keep the old caps just in case. I didn't have that problem when i replaced the caps on my RSb thankfully
 
tubed said:
Unless you are itching for a project, I'd just change out the small electrolytics and make sure they're wired correctly.
They sound good stock.
If you must, try front to back 1"X2"s at the woofer screw holes(one woofer is a no go with the crossover in the way) however that cabinet didn't seem to have too much resonance vibration.
View attachment 904986
Click to expand...
i will work on one crossover at a time and keep the other for reference until i test out the first finished speaker. Not sure what you mean by a front to back brace, as you can see from the picture there is already a brace between the woofers, like you say another can't be put below the bottom woofer as that is where the crossover is. so do you mean additional braces next to that existing brace? Or additional braces above the top woofer?
 
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probably want to add some more stuffing. When I did mine I was able to add 1.5 bags of poly fill to each cabinet. Nice and full into all corners, but don't stuff tight.
And at that point, the stuffing will want to expand into the backs/frames of the woofers. get two pieces of burlap and slide in, between the woofers and the stuffing. My Jo-Anne's fabric has black burlap, looks nice.

my 2 cents Stu
 
srb02 said:
probably want to add some more stuffing. When I did mine I was able to add 1.5 bags of poly fill to each cabinet. Nice and full into all corners, but don't stuff tight.
And at that point, the stuffing will want to expand into the backs/frames of the woofers. get two pieces of burlap and slide in, between the woofers and the stuffing. My Jo-Anne's fabric has black burlap, looks nice.

my 2 cents Stu
Click to expand...

thanks for the tip Stu. did you reuse any of the original filling that was inside the cabinets? it seems like there was quite alot of white stuffing inside with a white mesh-like sheet between the drivers and the stuffing. i just weighed it at 600g (1.3 lb) is what was inside one cabinet. how heavy is your "1.5 bags"? i notice that the bags come in different sizes...btw poly fill is just polyester stuffing like this right, not any special brand name? http://www.walmart.ca/en/ip/64oz-1816g-polyester-stuffing/6000115629128
 
Yes, all the original stuffing, and added approx 1.5 bags to each cab. Weight? Bags are 12" in diameter, and about 20" long. (Small pillow)
Yes, that's the stuff.
 
I'd assume the original amount of polyfill was the correct amount Infinity intended for the RSIIIa design.
Adding more "stuffing" effectively increases the volume size of the cabinet, for the better or worse?
 
tubed said:
I'd assume the original amount of polyfill was the correct amount Infinity intended for the RSIIIa design.
Adding more "stuffing" effectively increases the volume size of the cabinet, for the better or worse?
Click to expand...

I'm working on RS3b, not RS3a (do they use the same cabinet dimensions?)
I assumed they used the proper amount of poly fill for the cabinet as well but I'm open to adding additional poly fill or foam if there are benefits to the sound..
 
Refoaming went mostly well. I was running the test tone at around 9 o'clock and everything sounded good. Set the glue to dry then tested them the next day. I'm getting some weird vibrations on one driver though when listening higher than 10 o'clock. Doesn't sound like the voice coil rubbing sound though? More like a 'thhwack, thhwack, thhwack' sound. When the power is off there is no voice coil rub sound when I push the cone down evenly. ... The glue seems good around the: foam, dust cap, and spider.
Wire leads seem to be good, it's hard to tell if they're hitting under the cone but I don't think so... So not too sure what the problem is.
I decided to test them out in the cabinets and I can't hear that same sound when testing at 12 o'clock with actual music. Guess I'm going to live with it unless anyone has a suggestion?
Here are two videos. First video is with the noisy woofer, volume starting at 8 o'clock going up to 11 o'clock then back down. Second video is one of the other woofers without the noise for comparison.
Thanks!

Noise: https://drive.google.com/file/d/0Byq5qyUF-yfdcWhMNUdPcUwzZ0k/view?usp=drivesdk

Normal:
https://drive.google.com/file/d/0Byq5qyUF-yfdNGhoN1NNYVlHZEk/view?usp=drivesdk
 
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check internal wires vibrating against the cabinet, I had this happen with a pair of RS 525 after refoaming, I inverted the woofer to hopefully guard agianst sag, and it caused one of the speaker leads to rub and create a horrible vibrating buzz sound, I though the woofer itself was doing it.
opened up, re-inverted woofer, problem solved. That was near ten years ago

Listening to them right now.
 
Congrats on the fine speakers. Love the classic Infinity sound. I have RS5b, RSII, and a pair of RSIIIa coming from a fellow AK'r next week (weather permitting).

My RS5b had fiberglass in them, so I switched to poly-fill, just because.

Those woofers were designed to play in a sealed cab, so the air "spring" helps keep them from bottoming. A good seal is needed. I use rope caulk like the stuff AR used back in the day. Cheap at any hardware store and stays pliable for years.

Check the screws holding the tweeters together. Mine were pretty loose after all the years.

There's generic "Dynamat" out there. About 1/3 the cost, and it's the same thing. I've used it on two vehicles and a pair of DIY speakers. It certainly adds weight and damping. without taking up much internal volume.

Infinity used very high quality film caps, so like others have stated, just replace the electrolytic caps. You may want to clean the pots. They are pretty tough to get into. I measured mine and they are still smooth and accurate after all these years (RS5b).

FWIW they like a bit of clean power on tap. More the bettere, just be careful of the volume control. YMMV
 
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