[DawgByte]

Great story, Audiobudha.  There is nothing like putting in the work and time with the end result being a true reward. 

Oh, and the 5A's cost $17,995, not $9,000. 

I am off to read the Stereophile link you provided.  Thanks!

Remember this was 9 years ago. The dealer was selling them for $9K. I think they were floor demo's that may have impacted the prices. In any event they were out of my range. 

[Nuance]

^ Wow, that's an amazing price for a pair of 5A's!  Sounds like your C-5's sound better to your ears though, and that's all that matters.   

[gkinberg]

Jim, I had a question or two regarding the quote below from one of your posts. The Rythmik sub that you compared to the song sub was presumably crafted and altered in your shop and had different specs (size, amp etc..), please correct me if I'm wrong. Therefore, I assume that the modified "Rythmik sub" had been improved over the original design that one would purchase from rythmik. If that is the case, then I also would assume that if a stock rythmik sub was run head to head with your songsub, it might not compare as favorably?

I'm not trying to step on anyones toes here, just trying to determine where my hard earned dollars should be spent.  Please feel free to respone to this post in a PM if you think that is more appropriate.

Thanks for your time, Garth

When we built the first 15" Rythmik sub, we tested it against our SongSub.  We set the crossover at about 80Hz and ran music and tones.  The SongSub is a very low distortion sub and the two tracked very similarly to a point.  As the bass went deeper, however, the Rythmik took over.  Of course, it should have since it has more displacement - a 15" driver should move more air than a 12" driver, all else being equal (there is no substitute for displacement).
- Jim

[jsalk]

Garth -

Jim, I had a question or two regarding the quote below from one of your posts. The Rythmik sub that you compared to the song sub was presumably crafted and altered in your shop and had different specs (size, amp etc..), please correct me if I'm wrong.

The Rythmik subs we have built to date use the same drivers and amps as the stock Rythmik product.  The drivers have an extra voicecoil that is used for the feedback circuit in the Rythmik servo amp.  And the amp itself contains the servo circuitry.  So if we do a Rythmik design, we have to use their drivers and amps.

Rythmik subwoofer cabinets are made from well-braced 3/4" MDF.  When we build them, we use either 1" or 1 1/2" MDF and similar bracing.  So our cabinets would tend to have slightly less cabinet resonance (and would be quite a bit heavier, of course).

The most recent sub we built for Josh, uses two 15" passive radiators rather than a port.  This allows the sub to play as deep as it would if ported, but there is no port noise.  When you get down to 20Hz or lower, the air velocity out of a port is quite high (you could probably dry your hair with it  ).  You can get rather severe port "chuffing" from this type of set-up.  Using passive radiators increases the parts and labor costs in building a sub, but eliminates the possibility of port noise.

Keep in mind here that there is nothing magic about subs.  Take a great driver, give it a well-braced cabinet with the volume it requires, supply enough wattage and you're in business. When compared to stock Rythmik subs, we can certainly build more inert cabinets and we can employ passives.  But I think the main reason people have us build their Rythmik subs is that they can have the exact same finish as their speakers.

Therefore, I assume that the modified "Rythmik sub" had been improved over the original design that one would purchase from rythmik. If that is the case, then I also would assume that if a stock rythmik sub was run head to head with your songsub, it might not compare as favorably?

I wouldn't say that.  I would say that a stock 12" Rythmik sub and a SongSub would be very comparable.  The Rythmik sub may have slightly lower distortion due to the servo circuitry. (That said, the SongSub is a very low distortion (VLD)  design.)  On the other hand, the SongSub has more power and uses a passive radiator, so there is no port noise.  Performance of the two subs would be relatively similar, but the SongSub's added power, coupled with the use of the passive, might be an advantage to some users.

If you compare the SongSub to the 15" version of the Rythmik, that is another story.  The 15" Rythmik will play deeper than the SongSub and with more authority.  There is simply no substitute for the added displacement of a 15" driver.  If we built a custom sub with a 15" driver and a pair of 15" passives, the playing field would be more even.  In that case, it would come down to a trade-off between and servo circuitry in the Rythmik and the added power (and perhaps the use of passives) you could have in a custom 15" sub.  (The 15" driver we would use in a custom sub would essentially be the same driver without the servo voicecoil.)  Since we have never done a comparison, I don't know how they would stack up.

As I indicated above, I think Brian is working on a higher power servo amp which would eliminate the power disparity.  In that case, I would tend to choose the Rythmik set-up since the cost would be similar and the set-up would take advantage of servo technology.  And we could still use thicker walls and perhaps passive radiators resulting in the best of all worlds.

I hope this helps.

- Jim

[gkinberg]

Jim,

Thanks for the post. While information is always useful, it doesn?t always make the decision process easier 

Garth

[floresjc]

Garth -

I've only had my dual passive sub about a week, but I'm in love with it. As Jim said, it has the stock driver and amp from Rythmik, but he did beef up the design by doubling the wall thickness, adding two passive radiators, and the veneer matches the rest of my setup. Its a beast to move at 140 lbs, but it sounds wonderful whether doing 2.1 channel music, stereo/dolby digital TV, or movies. Truly a versatile piece and beautiful to boot. I wouldn't hesitate to recommend this type of sub (Rythmik + passive radiator) to anyone, although it does cost quite a bit more than a stock SongSub or Rythmik.

Josh

[gkinberg]

Hi Josh,

Thanks for the input. I can only imagine how nice your sub looks and sounds. I think that the aspect of passives in the Rythimk design is ideal and would love to opt for it. However, I'm on a budget and the cash that I've allocated for the sub would only swing the songsub or the stock Rythmik. So, basically I'm jealous of your awesome setup. 

I?ll ask but you don?t have to tell me; how much did it cost you to have Salk build the custom sub for you.

Enjoy and take care, Garth

Garth -

I've only had my dual passive sub about a week, but I'm in love with it. As Jim said, it has the stock driver and amp from Rythmik, but he did beef up the design by doubling the wall thickness, adding two passive radiators, and the veneer matches the rest of my setup. Its a beast to move at 140 lbs, but it sounds wonderful whether doing 2.1 channel music, stereo/dolby digital TV, or movies. Truly a versatile piece and beautiful to boot. I wouldn't hesitate to recommend this type of sub (Rythmik + passive radiator) to anyone, although it does cost quite a bit more than a stock SongSub or Rythmik.

Josh