Glad you decided to get on board here on AVS. It's always good to have perspective from a HT dealer. I hope you continue to participate here and find it an enjoyable experience.
I think your assessment of the subs in question is pretty accurate overall, though I haven't heard them all extensively (and a couple, not at all). The Velodyne should have decent output above 40hz and its EQ can prove beneficial in taming room issues. I owned the Infinity PS212 and I suppose I was fortunate because I had no amp issues. It sounded decent and had good output above 35hz. However, I've read about the amp issues and would be hesitant to buy one now. I haven't heard the other subs much, but your sentiments echo others I have read.
I do have to take issue with the following statement, though:
Originally Posted by Marc M. Johnson
any $500-$600 sub that tells you it can do 25hz is full of it--they lack the amp power or the driver isn't robust enough
Perhaps this is the case with subs sold in brick and mortar stores from companies such as Velodyne and Klipsch, but today's internet direct subwoofer industry has a number of <$600 subwoofers that can dig to a real 25hz and below. Here are just a few:SVS PB10-NSD
($449) - solid output 20hz (slightly deeper in-room)SVS PB12-NSD
($569) - strong output to below 20hz (upper teens in-room)Hsu VTF-1
($449) - good output to 25hz (closer to 20hz in-room)Hsu VTF-2 MK3
($549) - digs to below 20hz (upper teens in-room)AV123 MFW-15
($499 on sale) - strong output to ~18hzeD A2-300
($350) - output to 20hzeD A3-300
($550) - strong output to 20hzOutlaw LFM-1 Plus
($549) - strong output to slightly below 20hz
With the exception of the Hsu VTF-1, all of these subs should be capable of substantial output at 20hz (at least 90dB 2M GP). They also sound quite good (I've heard some of them and previously owned two PB10-NSD's myself), are backed by excellent service, and usually have a ~45 day money back guarantee (though the customer may be out shipping costs).
If you haven't yet had the chance to hear any of these ID offerings, I'd encourage you to get a demo from someone who owns one. I think you'll be pleasantly surprised
Again, welcome to the forum.