do you need a special servo amp or std amp will do?
Yes you must use the Direct Servo amps. They are available through Rythmik Audio. I believe that they are currently $229 or $249. for the older models and they are in stock. I am sure Brian can chime in with the actual price.
The new amps have some really nice added features like an EQ system and variable 12db and 24db per octave settings. The new amps should come in at the $279 to $299 range. I'll make them available for order on my site as soon as they become available. The last time I spoke to Brian he said it would be the end of Feb. on these new ones.
if the former is true then the price will increase, become less economical.
Even if the new amps are $299 plus $149 for the woofer, that's only $448. That won't buy you the biggest, the loudest, or hardest hitting sub on the market. It gets you the best sounding, most accurate, most articulate, and most musical sub on the market. That sounds like a bargain to me.
It will also get you a flat response to below 20Hz in only a 1.5 cubic foot sealed box. I don't know of any other subs that can deliver that either, not with this level of driver control.
I think the Exodus Audio sub woofer amp does not need servo amp.
You can run all of these subs off of a conventional non-servo amp too. But why?
If you want a something in a lower price range we offer a great SW-12B model for only $99 each. There are a handful of amps listed here for under $100: http://www.apexjr.com/amps.html
Clearly there are less expensive alternatives if that is what you are looking for, but no greater quality can be had than these new servo driven combos at any price. They are that good.
Danny,
Sorry to come to the rescue late
The current version of amp will be $249 when purchased separately for Danny's 4-ohms drivers. This is the so-called 12db version on Rythmik Audio web site, mainly for those have HT receivers and use the bass management for front and subwoofers. The 24db version will be $20 more expensive. The shipping is flat $21.
The new amps will be delayed to the end of March. It will have the one band PEQ and 12db-24db switchable Lowpass filter on the sub.
Is it worthwhile to spend extra money on GR/Rythmik servo kits?I normally post on avsforum. Over there I have explained the advantage of servo over nonservo (or Linkwitz Transform). Nevertheless, customers' feedback is far more important. So far the feedback is very consistent this is one of the fastest and cleanest subs. Personally I sell both Linkwitz Transform based kits and servo kits. The servo kits consistently outperforms LT-based kit with clarity and coherence. There are so many reasons for that:
1) servo reduces boxy sound. That is, it controls the cone against the reflection sound waves from inside of an enclosure. Our servo reduces the transmission of the secondary reflection via the subwoofer cone to the external by a factor of up to 3x. That is why these subs do not sound like just another subwoofer with non-offensive sound. It is actually very different. It is clean and goes low.
2) The transient response of a sealed box is mainly determined by the Qts value of subwoofer+enclosure. Our 12" kits (same as Danny's) has a Qts value of 0.3 (or less depending on models) when it is in an enclosure. That is 3 times lower than nonservo. Our bass can literally stop on a dime and that is from our customer's feedback.
3) Most people think putting multiple drivers or having a larger excursion will improve the bass. As a matter of fact, other than making it play louder, it does not improve the Qts, nor it improves the cone control against the internal reflection. So it is still the same old sound.
4) The spider/surround distortion makes the bass sound less coherent. This mainly manifests itself as a lack of details or dynamics. Our servo can reduces the spider/surround distortion by 3x. I used to have the story about 16ohms LS3/5A monitors on my website and how that speaker becomes the most sought after among all LS3/5A. When I sold mine on ebay, I got 6 or more questions if mine is a 16-ohm version . I, just like most other not familiar with the situation, mistaken that 16ohms version sounds better because it is an easier load vs later version as 8ohms. It turns out it has very little to do with the impedance. Rather it is the new surround material that they used on the mid-bass driver that degraded the sound (making it less dynamic). Using multiple drivers or a driver with high excursion is not the answer for this challenge either.
5) Our servo has negligible thermal compression as long as you don't play at full power. That is because our frequency response is not affect by the temperature of the voice coil. We have a consistent Q value for our bass roll-off, no matter it is in the Arizona desert or Colorado snow mountain. At the same time, because we can make the bass extension so low, we can offer 3 extension settings (14hz, 20hz, and 28hz) and 3 damping settings(Q=0.5, 0.7, and 1.1). All the damping settings are set up by electrical components which has an error of less than tolerance of speaker components. Coherence is the name of the game here.
So the final question is if you care for a sub that will sound so clean and clear that you feel like you have just upgraded a CD player. I wouldn't have any doubt.
Brian
