Comparing RTA 12 to RTA 12B

wachsone

First let me start by saying I'm just here for discussion and while I feel I have an ear to compare fine details I'm no expert.

I inherited my Dads RTA12s and a Luxman R1050. He bought these new in early 1980. I was the high school kid who's Dad had the kick **** stereo or so we thought. Recently I found a set of RTA 12b for the right price so now fast forward to the a/b comparison though the Luxman receiver. Granted there has been no upgrades to either set of speakers. The Lux has just been serviced and performs as it should. My take on auditioning the two sets is as follows.

The 12s are boomy but warm with a bit of emphasis in the midrange. Some songs I actually like the sound of them though. The low end hits hard. The highs seem as they should. The mid range vocals just are "in your face" to some degree.

The 12Bs have a much cleaner open air sound to them. The highs are definitely bright in comparison. The mids are weaker, again to the point were I like the 12s better. The lows don't hit as hard but doesn't have the boomy effect either.

I have thought of upgrading my Dads old 12s but if the upgrades are more in line with the sound of the 12Bs I'm not sure the upgrade is worth the effort. I know everyone says the caps NEED to be done. This then starts the snow ball effect with other upgrades including tweeters. Not sure Id be happy spending the money to have overly bright highs. I have never listened to an upgraded set of old polks. If anyone is in the northeast Wisconsin area....


Thoughts ?

Nightfall

Which tweeters are in the B's?

wachsone

Peerless

Nightfall

I've never heard somebody describe Peerless as bright.

F1nut

Nightfall wrote: »

I've never heard somebody describe Peerless as bright.

Me either.

westmassguy

Your Dads12s have the raised base? If so, the 12Bs should outperform them. Both have very complex crossovers, loaded to the gills with NP Electrolytic Caps, however the Bs have added compensation in the Crossovers for the side by side woofers. The 12Bs should also provide better deep bass due to the larger cabinet and PR tuning.
Both would benefit greatly from a crossover refresh.

Mystery

Actually, peerless are bright.
When I compared them against sl2000, peerless are brighter but not shrill.
The peerless have more projection and have some force/tightness to them so they sound brighter and stronger in a good way.
I usually turned treble down a notch or two and it balanced out.

Jazzhead

I have a pair of the original RTA-12's I bought in 1980. The crossovers are with westmassguy currently for the "refresh" (new Sonicaps and Mills resistors). In their stock form, in my room, with my gear, I have rarely found them to be bright with the exception of some CD's which to my ears were recorded too hot. Most of the time my source is a Cambridge Audio 840C, and some have reported some "glare" associated with this player but that hasn't been the case for me. That said, I've been very careful to isolate it from vibration and microphonics. The player sits on four Herbie's Audio Labs Tenderfeet in direct contact with the chassis (as opposed to under the stock feet); and I've found the Tenderfeet perform better placed near the center of each side of the player as opposed to each of the four corners. This all sits atop a thick glued-up baltic birch isolation platform with four Herbie's Big Fat Dots under the corners to further decouple the whole works from audio cabinet vibrations. The sound is warm, detailed and well focused - it's a good player for what it costs. When I get the crossovers back I am going to finish all of the standard upgrades, as well as replace the internal wiring with some Neotech UPOCC wire (14 gauge). I want to be able to hear the changes as I do each upgrade. My 12's have never seemed boomy, but my room has several large upholstered pieces of furniture, and other items that are acoustic sponges. They also sit atop the 12-inch Polk Stands and come alive with four Big Fat Dots underneath them. The low frequency is pretty tight, and I am always surprised by how deep they dig for the size of the cabinet. I imagine this will all improve when I get to hear capacitors that are not 36 years old. These speakers like power, but can sound "shouty" to me in the upper midrange if I throw some real juice at them (but I rarely listen loud). I am hoping that Black Hole 5 or Sonic Barrier behind the midwoofers will cure that problem.

Nightfall

Jazzhead wrote: »

...but can sound "shouty" to me in the upper midrange if I throw some real juice at them (but I rarely listen loud). I am hoping that Black Hole 5 or Sonic Barrier behind the midwoofers will cure that problem.

I have had the same experience with both the RTA-12B's and SDA 2B's and I am also hoping that BH5 will help that out. It keeps me from turning them up for more than a short while. Others have told me that room treatments will help.

dromunds

wachsone: where you located in northeastern Wis?

Jazzhead

I want to add that it's my experience that the original RTA-12's greatly benefit from replacing the stock binding posts. I replaced mine with Cardas posts. Since my plastic binding post cups were cracking at the screw holes I installed the new posts on some circular aluminum plates that I had fabricated at a local machine shop. My stock posts were not soldered, just lugs bolted to the posts, and coated with what appeared to be hot glue. There was a definite audible improvement. It's possible that it would be difficult to truly evaluate these speakers without renewing that connection first.

wachsone

Dromunds, just reviewing this thread and relized I never responded. Im in the fox valley area, Kaukauna.

erniejade

Some boomy could also be from speaker position. When you were testing them out, was one set closer to a corner vs the other or did you put them in the exact same spot? That also might by why one bass seems a bit weaker or different.

Schurkey

What point is there in comparing two pair of speakers when we know the caps are past their service life, and the fiber stuffing may no longer be tucked where it's supposed to be?

You're no longer comparing speakers, you're comparing how the speakers have degraded, relative to each other.

geppy1

The original RTA 12s and RTA12B ad Cs are completely different speakers. The B and C version have larger cabinets. The B uses 6600 drivers with peerless or SL 1000s The C uses 6501s with SL 1000 (early) and SL 2000s. The B and C are mirror image speakers with the outer drivers rolled off at 600 verses 2000 for the inner drivers The original RTA 12 does not do this. Iit use 650s and peerless It is like a Monitor 10 with a 12 inch passive and open air mounted peerless tweeter. The B and C also went to great lengths with the top hat and ramp to control diffraction effects.