Subwoofers.... one 10" or two 8"?

larstutor wrote:

My OMD-15s are sitting a a very solid hardwood floor over a plywood sub-flloor built on a concrete slab. Contact between the speakers and floor is rock steady. I wonder if I'd get more bass by putting the speakers on feet to isolate from the floor. It's hard to imagine an 8" subwoofer going down into the 20s. How does the HRS8 sound at moderate listening levels?

Are you using the Mirage cones for seating the speakers on the floor? Otherwise if they're just sitting flat on it that could reduce the bass. My mid-'90s M5si's have bass wherever you put them. The OMD-15s are capable of low 30s bass, but can drive you crazy trying to find it.

When it comes to sub power and depth, diameter isn't the only factor in making a strong wave; excursion matters, too. Total volume displacement is the diameter times the maximum excursion. Bob Carver and Sunfire practically invented the high excursion subwoofer driver, with that big reverse roll surround that would allow a 1" excursion when 1/4" was still considered extreme. Of course going up in diameter *plus* the high excursion makes it deeper and stronger yet, but Sunfire claims to extend into the 20s and the reviews I've read of their subs indicate that they tend to go as deep as they claim.

I'm sorry if I gave the wrong impression; I haven't heard the HRS8 so I can't comment on room-filling capability. But I have some reason to trust them as I've heard other very compact Sunfire subs. 

As for the NHT Classic Ten and Energy ESW-8, I think you're shooting too low. The Classic Ten was designed to mate with a dual-woofer tower and the ESW-8 with the Energy Take 5 miniature system. If you want to add a real bottom end to the OMD-15s (which I think is worth doing), you'll have to up the ante unless you luck into a deal. 

Consider the SVS SB-1000, a 12" sealed enclosure (best for music) powered sub that's $499 in black ash or $599 in piano black gloss. This one should be plenty fast and elevate your OMD-15s to a higher (and lower :-) ) level. Lots of positive professional reviews.

• Goodsound (Soundstage)
  
• AudioFi.net
  
• Sound and Vision
  
• About.com
  

The take away is that SPL is key. And fortunately most music doesn't contain much bass.

Exactly, especially given that 2-channel music is the OP's primary use of the system. I have used a Mirage LF-150 (10" x 150w) and an LF-100 (8" x 100w). Believe it or not, using the Stereophile test & demo CD, both subs produced clean, clear sub-30 Hz warble tones easily audible from the listening position about 8-10 feet from the subs. They might not be the best thing for crashes and explosions for HT in a large room, but for 2-ch. stereo they did surprisingly well. The more upscale sealed w/ passiave radiators Mirage MM8s do better (on transient response, clarity, etc.) but don't go as deep as even the modest LF-100.

I've also heard the SVS SB12 with full-range speakers in a fairly large media room and it acquitted itself well on 2-channel music. I think it's a good candidate for the OP. 

How good are Dynaudio subs? Anyone tried?

I have had over the yrs probly 10 different subs . The original 8" sunfires with my mg3a sounded killer .. I had a pair  of the better 10" velos granite looking base with kefs they were imo not as good as the sunfires anong other velos, a single rel few yrs back 12" it was nice i have a hrs 12" sunfire on spikes now it gets boomy if its not placed right . I would like 2 10" in my room but honestly there are many times i dont even use the sub. There are many things at play with a sub regarding placement , straddling corners etc. but i never knew how good the low end sounded until i started working on room acoustics . Regarding small subs and high distortion i can't comment , i only know what sounds good in my setups over the yrs . The only 15" i ever had is the velodyne i have a model i can’t remember at the moment it was around a g retail is in my ht room its huge and rattles the house but tight is it not . 2-8" = 😬 2-10" = 😃 2-12" = is overkill in a small med room . Jmho .. Treat that room with some bass traps of some kind you’ll be surprised.👍😄