MoFi Sourcepoint 8 or Q Acoustice Concept 50s

One particular aspect to pay attention to is the SP8’s high impedance around 2 kHz (see the first chart), which can cause slightly elevated highs relative to the midrange, especially when driven by a tube amplifier. Note that this characteristic also exists in the SP10. That’s why the latest SP10 ME (Master Edition) includes a three-level treble attenuation switch to tame it (see the second chart). Of course, it comes with an additional $500 price tag. It’s unclear whether a similar switch and crossover upgrade will eventually be available for the SP8.

In any case, some people are more particular about these nuances (like me), so it’s worth paying close attention to such details as reflected in expert reviews. The effect on the SP8 may not be obvious and might not be noted by reviewers.

(both quoted from Erin)

An amp with a high damping factor(almost every solid state amp) will not have any frequency variation due to wide speaker impedance swings in the speaker load. However as stated tube gear will show frequency variation because they always have low to very low damping factor.

By the way there will be frequency variation in the bass with low damping where there are impedance peaks from box resonance and port resonance.

@lanx0003 well luckily their amp isn’t a high output impedance tube amp. it is solid state AB amp with high damping factor so impedance mismatch isn’t going to be an issue here

@maam522a get the Sourcepoint 8. 

Have you had a chance to listen to either pair of speakers at your local dealers, or at a show?  Me, personally, I wouldn’t purchase the most critical component in my audio system (speakers) without first being able to hear them in person somewhere, somehow.  Seeing as it my be impossible for you to be granted an in-home audition, I would even travel a reasonable distance in order to audition.  Once I decided on the speakers, then I’d purchase, trade, exchange, amplification that synergizes with your speakers of choice.  Or, you could buy based solely on what you think would synergize best with what you already have.  You have subs, so you don’t have to worry about low bass extension.  Good luck.  Happy listening.