Hi Rosa,
It is certainly OK to prefer the CBM-170 over the 340 main…
both speakers were designed for specific purposes and what sounds best to you is purely subjective.
From a technical standpoint, the CMT-340 is superior… The CBM-170 uses a single high performance woofer while the 340 uses two. In any loudspeaker, distortion increases as output increases. Depending on how you look at it, the 340 has the capability to deliver either twice the output of the CBM-170 at the same distortion level, or close to half the distortion at the same output level.
The tweeter used in the CMT-340 is also technically superior, having lower distortion, a lower resonance frequency and extended high frequency response.
We actually post a very revealing graph on our website called the cumulative spectral decay. This is seldom understood, but still a highly important measurement. This is a measurement of a fast impulse consisting of thousands of frequencies ranging from 400Hz to 20Khz. What the graph reveals is what “noise” is left over once the initial impulse stops (in milliseconds). Notice on the 340 graph that there is very little (if any) artifacts left over after 1.92 ms past 2kHz (this is really amazing actually). On the CBM-170, there are artifacts between 2kHz and 5kHz almost reaching 3.5ms (about half that of the 340, which is still, quite good). Also you might notice more artifacts in the high frequency region as well..
CMT-340 cumulative spectral decay
CBM-170 cumulative spectral decay
From a purely objective perspective, the 340 is a more transparent, more revealing speaker and I believe this is what you might be hearing… Sibilance is almost never produced by a loudspeaker (certainly not from a high performance product like the 340); instead the sibilance you are hearing is being reproduced more clearly from the 340 than the 170…
Sibilance can be a real pain to track down, but with some patience and logical troubleshooting procedures… the source can be found and resolved...
First off, we will need to know if you are hearing this on all sources or just some.
1. When listening to TV? Are you using cable or satellite?
2. Are you hearing sibilance when playing high quality CDs or just certain recordings?
3. Are you hearing it when playing DVDs?
These are the first steps needed to start the troubleshooting process and with your cooperation, we can resolve this. Since we will need to go back and forth on this, it is best if we handled this through email…
Substituting the 170 for the 340 so you no longer hear the sibilance is just masking it… it is still there, just not being reproduced as audibly.
Hope this helps!