Servo sub woofer

Addendum

I think that the Rhythmik kit is the best one for you because you can have the satisfaction of DIY but the performance of a servo subwoofer. This is not an accelerometer based servo system and has good stability. This will being you closer to true accelerometer servo perfomance (which is what you may be accustomed to) than even a critical Q box. The price of admission is higher than a typical sealed-box or vented-box sub but then again, it does have a specially-designed servo circuit. Just knock together one of their recommended sealed enclosures (for an EQ'd driver I recommend the larger sealed box option) and start enjoying servo bass. For just under $400 for the driver/amp kit, reviewer Ralph Calabria calls this kit a bargain. It seems a lot for a sub kit but remember that there is a complex custom-designed servo feedback circuit in the plate amp that had to also be designed by Rythmik; these aren't just off-the-shelf components.
 
BAM said:
The new woofer for DirectServo kits is made by AE Speakers. I can personally speak to the quality of AE Speakers woofers and their impeccable attention to aesthetics as well. The dark gray anodized single-piece aluminum cone makes for an extremely nice-looking driver.

I thought they were made by TC Sounds. Which would explain the TC portion of their driver's name. Definately parts sourced from TC sounds I am thinking. Not trying to take anything away from John at AE here (he is awesome), but I just don't think he is the one making those drivers. As far as I know, from being a Stryke/AE customer for many years now, John hasn't made a grey-anodized cone driver, let alone one that didn't have a dustcap or phase-plug of some sorts. Where did you get the info that John was making the drivers for Rythmik may I ask? Just curious is all...

Noidster
 
I had a discussion some time back with John about what he was workingon, and he said he was pursuing some possible production contracts with Rythmik Audio and ACI. I saw the new Rhythmik woofer and made the leap. In a later conversation with John I learned that the Rythmik guy wanted a certain voice coil length that wouldn't have worked well for his application. then the Rhythmik guy decided he wasn't going to mess with AE and had TC Sound build the woofer. It was kind of a stupid thing, really, since the voice coil length would really have to be what the Rhythmik guy specified so that the motion sensing coil would interact properly with the magnetic gap for limiting functions, whichwas a bad move on John's part
 
BAM said:
I had a discussion some time back with John about what he was workingon, and he said he was pursuing some possible production contracts with Rythmik Audio and ACI. I saw the new Rhythmik woofer and made the leap. In a later conversation with John I learned that the Rythmik guy wanted a certain voice coil length that wouldn't have worked well for his application. then the Rhythmik guy decided he wasn't going to mess with AE and had TC Sound build the woofer. It was kind of a stupid thing, really, since the voice coil length would really have to be what the Rhythmik guy specified so that the motion sensing coil would interact properly with the magnetic gap for limiting functions, whichwas a bad move on John's part


Interesting indeed. Probably something John didn't really want to take on right now anyhow as he is so busy with his own drivers and biz. I will have to ask him later this evening and get the low-down maybe.

Noidster
 
Servo drivers

Hi all,

Just to clarify, the new driver R12TC is indeed made by TC sounds. I did plan to source from AE. However, John cannot make them as soon as I had wished. And I had a list of customers waiting for the new drivers.....

Regardless of who makes the driver, I would like to assure you that the new driver is just as musical as the previous version (even though I actually pay more for them). The key features to make the direct servo kit sound so wonderful is really the servo technology, direct coupling of servo feedback signal, tight magnetic gap, low moving mass, and effective short circuit ring. The servo technology reduces the memory effect from the spider/surround and thermal memory from the voice coil. That is why our servo kits sound so articulate.


Please do not confuse our servo kits with those in Yamaha. They don't even have sensors in their drivers. So how did they get the servo signal? They use current feedback and market that as servo.

Brian D.

Rythmik Audio
 
I am not familiar with ML's servo sub, but our servo sub does have multiple damping settings. The high damping setting is Q=0.5. In addition, we have mid damping with Q=0.7, low damping with Q=0.9, and all of these can be set with a toggle switch on the plate amp. The user can adjust it according to the play back material or personal preference.

It is not clear at what frequency the 114db output is rated. But let us do a simple math. A 1.1" p-p excursion on a sealed 12" driver will give us 101db at 20hz. To get 114db at 20hz, it will need at least 1.1"x4=4.4" p-p excursion. However, if it is rated at a higher frequency, our servo subs can also achieve similar performance. For instance, at 40hz, our servo kit can get more than 1.0" p-p excursion which is more than 112db, and above 40hz, the output can go as high as 114db. So achieving 114db may not be not difficult, if no frequency is specified.

I do not claim our servo subs are the ultimate subs or have the highest outputs. But among all the subs that serve dual purposes (music/HT), our servo subs are pretty competitive if we digest the numbers a little bit.

Brian D.
Rythmik Audio