Kharma Sub Set Up- Review


I’d like to share my experience with other Kharma owners regarding integration of the new Kharma subwoofer with main speakers. I use CRM-3.2FE as my main speakers and was very excited when Kharma finally introduced a sub. With that said, I also acknowledge that I have tried numerous REL products (Stentor III and (2) Stadium III’s)
on different occasions with mixed results at best. The REL products were used with other speakers (Wilson WP7’s and Maggie 3.6’s).

My room is a finished basement approx. 18x23x7’4” with carpet over concrete.

Like most of you have seen at the recent shows (or pictures from the shows), the general consensus is to place the sub between the left and right speaker when using a single sub. The Kharma manual also states that this is a good location to start with.I initially set the crossovers in accordance with my dealer’s recommendation which proved to be a good starting point. BTW, the Kharma sub is the most tunable/adjustable subwoofer that I’ve seen. My results with this set-up were in my opinion OK and by far the best integration I’ve ever achieved with a sub. Well, that was until …….yesterday.

I called a friend in the area whom some of you may know, “Romy the Cat” and asked if he could help me with set up. I’ve known Romy for some time and trust his skills in system set-up and pointing me in the right direction in my quest for audio perfection.

Romy visited yesterday with all the tools of the trade. These included professional spectral RTA, RT60 and phase meters. His comment when first listening to my setup
was the integration was “deplorable”. Volume 8-10 db too high, phase off, peaks and valleys in the frequency response. These comments were based on his “ears” and not the test equipment. He also said the sub will never be optimized between the speakers.

Well, I insisted we measure the sub with my setup and Romy all the test substantiated Romy’s initial findings. Frequency response had peaks and valleys to plus 12db at 25 db to minus 11 db at 63 and 80 HZ. We moved the subwoofer to the corner behind the left speaker and after much experimentation/testing (3 hours) found the flattest frequency response to be with the sub driver FACING the sidewall. The driver is literally 4-5 inches from the sidewall. Our final settings on the sub were to cross it over at 17HZ and 70 HZ. with a 12 db/octave slope. This produces a relatively flat response in my room from 20-120 HZ. The worst peak or valley being –3 db around 40 HZ.

So how does it sound…………..absolutely stunning. Whether I’m playing acoustic jazz, electronica, rock or classical the sub integrates seamlessly and plays every note with weight, depth and the proper harmonic structure while completely disappearing (ala 3.2’s).

Anyone considering the purchase of this sub should take the time and effort to properly set it up. You will be rewarded handsomely.
rcupka

Showing 3 responses by howie

Rcupka, the point about subwoofer setup was a point I was trying to make in my response over at AA. The thing is that if you buy a REL sub from an authorized dealer, a trained salesman will help you with setup. And they have also developed a systematic setup process that is suppose to be easy to follow. I've had good experiences with REL subs in dealer showrooms so the idea of an easier setup could in the future become a deal breaker because I know I probably lack the tools and expertise to dial in my sub perfectly. Sometimes, it's only as good as the user's ability to use it.
Ya it sucks that this level of sound quality needs to cost so much. Not that you can't get good sound for less, but even at this level, there aren't enough great recordings out there that is satisfying in its own right compared to a good live session. The 3.2s were a huge purchase for me and I don't know if I'll do it again even though I don't regret buying it. I always feel bad when I think of all the money invested.

But ya, the 3.2s plus sub combo is essentially a 30K speaker system. I wouldn't say it's overpriced since it's certainly competitive with other 30K speaker sytems but it's one expensive sub especially with the price increase. Since I have yet to upgrade my source that's going to be priority over adding a sub. I don't know if I'll ever own a Kharma sub. The REL Stentor is quite a bit cheaper and might work beautifully. It also depends on how one plans to keep these speakers.
Unfortunately, most of us can only decide based on our own theories of what would work the best. Owl, you're right, in theory, a sub that is specifically designed for a speaker should integrate the best; that is the hope anyways. But that is in some ways a cop out. If I'm not mistaken, the Ceramique sub works like a traditional sub while the RELs are still unique in their sub-bass approach with no high-pass filter. Since on paper, the Stentors and Studios are more powerful and go lower than the Ceramique sub, I don't think you have to worry about room lock and whether it'll pressurize your room. Both Kharmas and RELs are known for the quality of their bass rather than quantity so to me, bass output and naturalness will not be an issue. I'm thinking that you'll simply get "different" quality bass which can be an effective way to tweak the tonal balance to your liking. Since this is a matter of taste, this is probably less of a concern as we can decide for ourselves what we prefer.

The main issue then is the matter of integration, since that has been the biggest worry with the Kharmas. In regards to the level of adjustability, I wouldn't worry about it. You don't need ten buttons to start the engine if you know what I mean, especially since we're talking about ease of setup. As I mentioned previously, I like the idea of the RELs augmenting the bass. When setup correctly, the RELs would simply pick up where the 3.2s left off, which in theory would do the least harm if it's fast enough to keep up. On the other hand, the Kharma sub IS designed for the 3.2s and there are now some positive reports on the combination but the RELs do have a high success rate of making a system sound better. Hmm...