I bought two of these sub to complete my current fleet of 4 x TTS18A, 2 x 4 x TT25A and TT22A.
One word, awesome.
I know the EAW SB850, S218 Martin, LA SB218, ...
I've heard plenty of other Sub, as the D & B B2, the F218 Function One ...
TTS56 the sound of a round, little Sub have same number!
Personally, I impress everyone who heard them.
I only have two and yet one gets the impression of having at least 4 double 18 "with the more rounded, almost too much! (I use the cut up to 45 Hz, it is to say).
Even at low volume, the sound is full and you hear an octave and more. With an incredible dynamic.
Yet TTS18A work very well (for 4 is already powerful and clean). With TTS56 I feel like I have 10!. (At the same time TTS18A: 136 dB / TTS56A: 145dB).
Both say direct, I am fully satisfied.
Certainly they are 90 kg and are quite bulky, but works well 2.
This was not worse than the S218 martin (with their handles crap) or the EAW SB850 (very heavy), while there, I'm amplified.
Small detail: the handles somehow cushioned! A kind of soft plastic! ^ ^
Now I swear by them! (I think selling a pair of TTS18A).
If you want more information on these Sub, contact me by MP.