High end Class D amps?

Some helpful insight here. Just starting to explore adding a sub to my system and wondering whether Class D is the way to go. The sub will run with an active crossover and is 94db efficient with a stable 8ohm load +\- 1db. I like the idea of a small mono block like the D Sonic but would appreciate opinions on whether Class D would be good in this application.

class d greatest strength is outstanding bass, so yes on that front

but dual subs are much better than one...  some will even say the best way is a 'swarm of subs' to smooth out the deep bass response, which can be very lumpy and hard to modulate with a single sub in many rooms

class d greatest strength is outstanding bass, so yes on that front

but dual subs are much better than one... some will even say the best way is a 'swarm of subs' to smooth out the deep bass response, which can be very lumpy and hard to modulate with a single sub in many rooms

I'm running a pair of Swarm subs with a class D amplifier, to break up the standing waves in my room. My main speakers go down to 20Hz so I didn't need 4 subs. Its amazing how well it works- the bass is absolutely consistent everywhere in the room now (a lot of bass was absent at the listening chair prior, with too much bass elsewhere in the room).

dodgealum Just starting to explore adding a sub to my system and wondering whether Class D is the way to go.

jjss49 class d greatest strength is outstanding bass, so yes on that front

Definitely the way to go, but there is a proviso, so long as the bass (sub) loading is "not too" much below 3-4ohms with high EPDR (-phase angle), "if not so" then Class-D’s high point is it’s bass and it’s claim to fame.

You’ll see that Class-D’s output impedance is measured in milliohms, not in 1/10’s of ohms like Linear amps. So for the same given subwoofer load a Class-D amp has a multitude better "damping factor" (woofer control) than a linear amp can do.

But saying that into a hard bass frequencies "loads" like a Wilson Alexia etc that have of 0.9ohms (EPDR), a linear amp like Gryphons etc etc will wipe the floor with the Class-D in the bass, because the Gryphon etc can do far more current into that 0.9ohm bass speaker load.

So you have a two edged sword for bass, "control" (damping factor) and (current drive), and it all comes down to what the load is that the sub is presenting to the amp, to which will sound the better for the bass, Class-D or Linear (Class-A,A/B)

Then you have to ask, which bass is the better designed, one that's an easy load or one that's a ***** to drive, I generally find the latter to give the better sounding bass when driven right, as they have usually been developed to the max, and the down side is a hard to drive impedance loading for an amp to see.

Cheers George

Hello dodgealum,

     It sounds like you already have picked out the sub you want to use and it's a high efficiency passive sub, with passive meaning it has no internal amplifier.  I just have a few suggestions for you based on my fairly extensive experience incorporating 1-4 subs in my system utilizing Magnepan main speakers with a rated bass extension of only 35 Hz:

1.  A pair of subs will perform roughly twice as well as a single sub in virtually any room and system.  The bass will be smoother, faster, more dynamic, as powerful as the source material calls for and with a greater sense of ease, more detailed and better integrated with your main speakers regardless of their speaker type.
2.  The bass will likely sound more detailed and natural to you if you power your sub or subs with a class AB amp instead of a class D amp.  The reason is due to the extremely high rated damping factors of most class D amps, often rated above 1,000 while class AB amps are typically rated in the 100-400 range.  
     The higher the rated damping figure of an amp, the more precisely it is able to control the starting and stopping of the sub's transducer, which I believe is a normal dynamic cone woofer in your sub.  This precise control is usually considered a beneficial quality in a sub amp.  But if the amp's rated damping factor is excessively high, such as over1,000 on some class D amps, then the amp has the capacity to very suddenly and abruptly stop the woofer as the woofer travels along its normal in and out  or up and down path motion.  The audible result, of a woofer suddenly and abruptly stopping along its path, is that the normal, natural, slow and gradual decay times of deep bass notes are truncated. 
     This premature ending of normal note decay times are more noticeable and annoying, of course,  on certain types of instruments, certain types of music and in the deeper keys.  The main point being your music will be audibly less natural and enjoyable, less so on most rock music than on other types of music in my experience.
     What's a viable solution?  I'd suggest you use a good quality but reasonably priced mono class AB sub amp like the Dayton SA1000 for about $300-400 from Parts Express or some other retailer, use a pair of good quality subs and optimally position each in your room, and in relation to your designated listening seat, by utilizing the 'sub crawl method' (which you can google for details).

Best wishes,
     Tim