Thank you for taking time to respond, ntrain42.
First, let me preface this by saying this is not to be meant as a slam on Rythmik. From what I've seen and read, they look like they make a very high quality product and are good to work with. But I have a couple problems with what you said:
I can understand using an off the shelf driver on a lower level product within their lineups, but Epik and HSU's description of their higher level products seem to contradict that statement:
HSU VTF-15H:
http://forum.hsuresearch.com/showpost.php?p=76547&postcount=1
Epik Empire:
http://www.epiksubwoofers.com/empire.html
It could be marketing word play, but I take those descriptions to mean anything but cheap and off the shelf.
I will have to do more research for my own benefit, but I didn't think that a Class D amp was a detriment to performance? It leads me to wonder what type of amplifier design works best for subwoofers....
Class D's seem to be pretty prevalent in the industry (SVS, eD, Seaton, Epik and HSU all seem to use them, though HSU does mention that the VTF-15 has a class A/B output stage). I think it would be reasonable that if Class D amps were underwhelming, these companies wouldn't be using them in their higher price range products (defined to me as being ~$2000).
Also, how did you come to the conclusion that these plate amps have a very high S/N ratio? Are there measurements available that you could share with us? I couldn't find anything on the Rythmik website making that claim, although I have not searched the net at large for that information either.
I am glad to hear that Rythmik has a responsive owner that is willing to work with his customers to get the best sound possible from his products. It's certainly not something you would be able to get from a B&M brand...
I don't understand why it is so surprising that these other manufacturers would not be willing to share that information - I'd consider that proprietary info and I would argue those companies have much more to lose by sharing that information to the public than they would in using it to convince the small fraction of the population that basically wants to double check the subwoofer manufacturers work. More disclosure is never a bad thing, but I'd have no complaints if that information was not available with a pre-made product. I guess it's a leap of faith on my part to believe that the people designing my sub are competent.
Rythmik has more of a reason to disclose things like driver T/S parameters, since they sell those products separately. I highly doubt that many DIY'ers would buy a driver without first knowing some specs. Also, in fairness to eD, they list some T/S parameters on their website as well (for the sake of argument, I'll assume those measurements are accurate):
http://www.edesignaudio.com/index.php?cPath=1_21
For example, that fridge sized A7-900 sub by eD states that it is using their Ov.2 subwoofer. It doesn't seem too logicial to me that they would us a woofer that had slightly different specs than the version used in their finished product. Although, I thought I remembered reading at some point that the individual JL Audio W7 subwoofers had slightly different specs than the versions used in their Fathom series...
Anyways, I think that's all I have. Thanks again for the response.
