Kappa 8 and RS3B compatibility

[Larry Morin]

Hi, I have a pair of Infinity RS3B’s and was considering using the Polydomes and Emit tweeters in a set of Kappa 8’s. Are they compatible with the Kappa’s? I notice the Kappas have a “k” on their tweeters and Polydomes so want to make sure I can swap?

 

[swechsler]

The EMITs are compatible, but the Polydomes are not. The Polydomes on the Kappas go a bit lower than those in the RS series. Some AKers have tried the substitution, but found it to be unsatisfactory.

 

[Larry Morin]

Thanks! I’m wondering if the Kappa’s would be that much better than the 3B’s anyway? With the dual woofers on the 3B’s the bass is hard to beat. I would imagine the Kappas would win the mid/high end quite handily.

 

[swechsler]

Having never heard the IIIB, I would guess that they're probably pretty comparable. Cabinets are similar and it appears that the Kappa 8 was designed to replace the IIIB when the RS series was discontinued.

 

[jazzmans]

Having never heard the IIIB, I would guess that they're probably pretty comparable. Cabinets are similar and it appears that the Kappa 8 was designed to replace the IIIB when the RS series was discontinued.

yes, the kappas are technically the infinity rs kappa (model number) and I believe @swechsler is right, the rs series polydomes don't go as low.

I really like my rs 4bs.

 

[Larry Morin]

Thanks,,,I’ve yet listened to anything “new” in the $2K range that beats my 3B’s. Is there a sleeper out there at this price range that might surprise me? Polk R700? Clipsch 8000? I’m looking down the road when my Polydomes will be spent and I doubt I’ll fix them,,Im I’m Canada and we have little or no options to repair the domes and replacement parts in decent shape are absurdly priced.

 

[swechsler]

The polydomes in the RSIIIA/B have no history of deteriorating. You should be set for life, other than refoaming and recapping.

 

[stereofanboy]

Thanks! I’m wondering if the Kappa’s would be that much better than the 3B’s anyway? With the dual woofers on the 3B’s the bass is hard to beat. I would imagine the Kappas would win the mid/high end quite handily.

I've never heard Kappa 8s, but I have 8.1s and have had RS IIIbs. I prefer the 8.1's bass especially when driven by an amp with oomph.

 

[swechsler]

I've never heard Kappa 8s, but I have 8.1s and have had RS IIIbs. I prefer the 8.1's bass especially when driven by an amp with oomph.

While I owned both 8s and 8.1s, I never directly compared the two. I will point out, however, that while the 8s and the 8.1s are both rated down to approximately the same frequency, the 8.1s are bass reflex while the other two are acoustic suspension, and some people prefer the sound of one design over another. I never felt the 8s lacked for bass, though (the 8.1s were in my bedroom, so never really got the workout they deserved).

 

[seifreit]

I’m wondering if the Kappa’s would be that much better than the 3B’s anyway?

I have both and IMO the K8s are definitely better than the RSIIIbs in pretty much every respect. The RSIIIbs would probably be more comparable to Kappa 7s with the only difference being two 10" vs a single 12".

 

[rxter]

I had a pair of RSIIIBs and found them to be really nice in the mid-range and punchy at the bottom. They did not have the ability to do the bass line of a rach 2 open, but they were very nice to listen to a reasonable levels and easy to drive. They also had a great aesthetic - one of the best looking infinitys IMO. I sold them and frankly miss them. I replaced them with a pair of Kappa 8s and replaced the cracked polys. They sound great and will bring the house down if you push them with a big amp say 250 + per channel. I drive them with an old HK AVR at 100 in my office and they sound fantastic. You can't go wrong with either one.

My recommendation would be to enjoy the IIIbs as they are and get a replacement poly for the 8s. Then you will have 2 sets of really nice speakers.