Sonus faber Cremona Auditor and Jeff Rowland??

What speakers did you have before? I have listened to the SF Auditors. Bass boom is not typical.

Room placement may be an issue. Have you tried to move them further away from walls? Also, make sure that they are not the identical distance from the back wall as they are from the side wall.

Bass boom can be a result of unique room acoustics. You might try some acoustic treatments. Eighth nerve is good: http://www.eighthnerve.com/
(I am not associated in any way with them)

I agree with Rubinken. If anything with break in, they should have less bass as the drivers are still not 100%. I have heard the auditors with Rowland gear at my local dealer and the match is quite nice. Try different placement options.

Hi, thanks to everybody's advice...

Well, my last speaker was B&W N805 and I know that my SF auditor has a quite different sound.
I don't expect to hear some speedy response from my Auditors like N805. What i want to hear is more Controlled-bass... ( sorry, I'm not a native English speaker...:) it is hard to explain what i felt in English...)
And that's why i suspect that my concentra does have a weak point in Damping ability...
Is it because of break-in process? if it is...than I'll be very happy because i don't need to spend lots of money to change new gears... since i really love my concentra..:)

I placed my auditor more than 3.5 ft away from the wall and 4ft from the side wall. the distance between speakers is little over than 6ft.
I'll try room tune as well... but Rubinkin, can you explain more about Auditor's placement?
This is my first time to try SF speakers and it is really hard to find information about Auditor's placement.
Moreover, my dealer seems to know little about the Auditor even he did sell it...
and... once again.. Thank you guys very much about every advice..:)
Hope i can learn more about this wonderful speaker.

Brain7466: I think you would find that the newer Rowland electronics - Concerto, 201s, 501s, 300 series, etc - would tighten and control the bass CONSIDERABLY more. Rowland gear has come a long way in this regard.

I wouldn't rule out the possibility of the Rowland and the SF being a mismatch, both are reported to be on the laid back side of the spectrum.

I am quite fond of the Concentra II, having owned one; here is what Rich Maez (of JRDG) responded to me when I asked about the Concentra and the Concentra II:

The CN I and CN II differ completely by power supply. The CN II has a much more powerful (50% more power) supply and therefore has much better control and power into low frequencies. It also has a separate front end supply that allows the unit to dedicate more power to large transients and make the CN II much more dynamic. High frequency distortion was reduced quite a bit with the second generation unit as well, so it has a much more open and extended high frequency response.

That said, it will cost you nothing to give your current setup more time, so I would suggest you do that first; it could take several months for them to settle in.