Originally Posted by JimP
So....which of the Rythmik subs are the most musical?
They are all very musical. They all have the same articulate, transparent, effortless, and coherent bass sound. You can tell the difference only when you place them side-by-side and listen very carefully. I contribute their distinct sound to 1) low intrinsic Q value (only 0.33, 3x lower than nonservo), and 2) extremely low memory effect. The latter is only possible via servo.
If one does not play very loud, then F12G with SW12-4 paper cone driver is very good and has slight edge in that area. Very dynamic at low level signals. This is particularly good if it is a pure 2ch system and when the background noise can be very quiet. The shortcoming of paper cone is it is not stiff enough. In HT, when huge short spurs of bass is often, the metal cone performs better to overcome the air spring (in both sealed and vented subwoofers) to stay in control. One can use a simple cone push test in sealed box. Our metal cone is very hard to press. Other similar paper cone sealed subs are still pretty easy. This test will not work in vented subs, because a slow push is equivalent to exercising the cone with a very low frequency signal and we know at close to 0hz frequency, vented sub behaves like in free air and very easy to push. One actually needs to push exactly right to emulate a 20hz stimulus to feel the reaction force.
I designed SW12-4 too and therefore I have access to 15" paper cone. I cannot get them to play right even with servo. That is the main reason, we don't see 15" paper cone from our line-up. It is possible to work in OB/IB application, but I don't want to step in IB cult community, and for OB, the 12" OB drivers fits in Danny's application perfectly.
So again, if one can comfortably crossover at lower frequency, the 15" is actually a better choice, having even better dynamic headroom. Between D15 and F15, I would say F15 is slightly more musically if one cannot xover at 60hz or below. I know a lot of customers like its furniture look and its appeal to spouse. But knowing the trick for them to work is also very important. Also don't put D15 on wood subfloor.
Allen and his friend (Mike?) in San Antonio came over to my house and I demoed the D15 with my 340SE fronts, Denon 4802 (hand modified to use first order RC to front channels), and an Ayre CX5xe. I crossover at 80hz and it is a music only system. My HT system is in my great room, but they are less interested. My interconnects are Kimber KCAG for the subwoofer and Discovery Signature for others. My power cables are Black Sand (from Canada). My 2ch room is upstairs with wood sub-floor, not a very ideal situation for D15, but he insisted on it. So,.. I have no problem with that. The trip was reported in Emotiva forum. He brought his own CDs. He was very surprised by the details in the sound (as compared with his own system). He contributes that to the CD players (I understand, it is 4k or more in retail). After he has gone through all his listening, I suggest that we lay the D15 side way so that the cone faces us and he immediately hears the difference. I was busy entertaining both and I didn't listen carefully. Besides, I am not really familiar with the CD he brought.
If there is enough demand by show of hands, I may be able to get some in for D12. But I basically like the idea that the cone should be facing us as much as possible to produce a strong direct sound energy. It is the cleanest sound. Anything that bounds off the boundary will mix with the resonance caused by the boundaries.