Subwoofer for under $1000-new, used, or DIY

I listen to mostly rock and classical. The sub would be for music only- no HT. I have GMA Europas, a Redgum 120 wpc int. amp and Audio Note tube CD player. I like my system very much, but it could use a little more oomph. My room is small (15x12x10). I've never had a sub before.

I have read about Hsu, ACI, SVS, Sunfire, Rel, Def. Tech., Totem, Titanic, Vandersteen, Rava, lots of DIY models, and a lot of others I can't think of at the moment. Frankly, it's all become a blur.

I am not a "bass freak", but do appreciate the low end of the musical spectrum. I won't say size is no object (smaller would be better), but of course sound quality is more important.

If you've owned or even heard any of the above subs (or any other in the price range) I would really appreciate hearing from you. Any comments or advice from my fellow 'goners (hmm..that didn't sound quite right) would be great. Thanks to all in advance.
The best sub I have ever had for music is an REL strata III. Intergrates perfect with my speakers.
The Europas are terrific speakers! Some added bottom end definitely won't hurt. What ever you decide make sure it's a sealed sub. You have plenty to choose from. For your room size I would look at 10 inch sealed designs. Something with a 150 to 250 watt amplifier plate. I wouldn't run the Europas through the subwoofer's crossovers. This too me would be going backwards. Since the magic in these speakers lay within the simple crossovers. Just do some research and listening..the sub your looking for will reveal itself.There's plenty of subs that fit this description that are new for under $500.
Have you ever tried ADS? The model that I would recommend for music is ADS Sub 12, or SW-500. I had a chance to heard many brand subs, ADS is outstanding but now they are discontinued. My brother has a High End store over twenty years and he still keept this subs. ADS design high-pass crossorve output so the Bass and your main speakers will be very clean. I agree with Gmood1, you should do some research and listening, don't trust too much on review. Good luck
I am very pleased with the Paradigm Servo-15 I'm using now. There is also a great sub that was just listed - a Muse18. He's asking $999 which is a very good price. If you are close enough to keep the shipping costs low, it would be a great option.
I highly recommend the Alon (now Nola) Thunderbolt. Very fast, very musical, even nimble enough to pair with planars. They are certainly powerful enough for HT, but where they truly excell is with music.

I always thought I'd go the REL route - and I heard way more subs I *didn't* like than ones I did, including most of the suspects you listed. The TBs iintegrate very smoothly with speakers - they are almost undetectable, making the music sound like it's coming full range from your speakers - I used to switch them in and out just to be sure they were on. The TBs totally disappear, but the monitors had all the bass and punch they needed.

Carl Marchisotto has revised the TBs now, so there are a couple of the original TBs for sale here at $700-800 (they're $1695 new.)
Of course for the money it will be hard to beat DIY. Maybe you should go to the madisound and partsexpress sites and ask them. Lots of great knowledge there. For a grand you can build a killer sub. There's some other good ones: M&K used, VMPS kits or assembled, HSU and others. These are all capable of very good articulation and power for music. I've not heard the Rel but have only read good. If you think you wouldn't mind DIY though I'd go that route. There's a diy called the sonotube:
I thought this would make a killer sub only I'd use a better and more powerful amp. Also it doesn't take as much floor space as a box. Good luck on your search. Subs are wonderful if you like the power in the bottom octaves. I run a sub on top of full range speakers from 45hz as I love the power of the first octave.
Here's one to add to your list. It uses 10" high excursion XBL^2 driver (XBL^2 patented by Adire Audio). Here' a link Acoustic Visions MRS-10 . This little guy should fit in your room nicely and it's small enough to add a second unit without space considerations. Just something to confuse you a bit more..LOL!
The Vandersteen 2Wq. It is considered one of the best for music and usually sells for around $750 used. It is not a ported design.
It's one of the best designed subs out there. It certainly isn't a rumble box, uses a a first order passive crossover between your preamp and amp. It is connected by speaker level from the amp.
I'm pretty sure the GMA are first order designs so this sub would fit right in.
These are supposed to better all but the most expensive subs.
Good Bass
I recently had a Definitive Technology SuperCube I in my room for a couple of months. I was using it with my Thiel CS2.3s. It really made the system sound alot better. It has a 10" woofer with two 10" passives and 1500 Watts for $999 (retail $1199). It was about right for my room which is 20' x 14'. You might be able to get by with the SuperCube II which has an 8" woofer with two 8" passives and 1250 Watts. I'm not sure what the price would be. Retail is $899. The only other subwoofer I've tried in my room was a 10" JBL from BestBuy which cost $399. It sounded like crap compared to the quality of my other equipment. The SuberCube really sounded good. Good luck on your search.
For musical bass, Vandersteen 2wq is the only sub you can get for under $1000 (used) that is what you have described. It is not a "Rumble Box" as mentioned above, but perfectly compliments speakers such as mini monitors, true ribbons, or electrostats.

Good luck
I'm wonder with A/D/S. I had a Sunfire signature for a couple months and trade Rel Strata III with my friend. Sunfire is good for movie but for music it has much distortion. Rel Strata is not good either, in my opinion. I have run around for many subs but not stay with me long. Finally, I have a friend who has many friends that are A/D/s fan and he invited me come over to his house for listening, I was suprising and really like it. I was looking for ADS sub, that took me four months to get it. Very hard to find. I really love this one, when it run about 20 Hz you still feel the bass and bass is very clean, many other subs can't do this job. If you are lucky to get one,you will not be disappointed. Take time go out to listen or find it. -:)