I felt cabasse had a more immersive movie experience [more bass, rumble] surround felt nice. KEF didnt have that immersive feel, though good still wasn't what I expected for movies. Not sure if it was tuning, the same AVR was also used for both. Later on I played flacs from my mobile, KEF felt more at home while playing music, Cabasse for music felt ok.
Later on Jayasheelan played some more music, wasn't happy with the output, on inquiring about the source of the music I was told MP3

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When auditioning, carry your own source material. Music material should be CDs or a USB stick with FLAC/high-bit-rate MP3 rip of numbers that you are very familiar with. If you have any BD/DVD that you are familiar with, then carry them too for movie audition.
Unless your mobile can attach itself as a readable USB device (windows and apple) or via wifi, don't trust it as a good source. Headphones jack and BT are for quickies not for auditioning.
AVRs are basically sound processors and video switchers (some exclusions here). Even in so called "stereo" mode, I suspect that the path is through ADC --> DSP --> DAC --> Amp. Suggest you try "direct" or "pure" mode the next time around. Many demo rooms are set up for HT. So if you are picky about how the AVR/speaker will sound for music, try with sub off/on, all supported music modes, tone controls, etc.
Coming to ProFx itself, I have been there a few times, but only once for a targeted audition. A couple of times it has been because I had to kill time while waiting for someone. The guys are courteous but sometimes the salesmanship comes through (can't blame them for this). I never heard Cabasse there, but have heard the Polk (TSX and RTi) and KEF Q ranges. Cabasse struck me as a lifestyle product. Polk was impressive for movies and KEF for music. Disclaimer, I own a pair of KEF R300s.
Here is how I would assess a system for music playback (please note it is not a generalization). Other FMs may add their methods.
1. Tune set should be male vocals, female vocals, duets and chorus, stringed instruments, drums, piano, synthesizers, tabla, flute, violin. With 8-10 numbers you should be able to get all of the above.
2. Stereo imaging and soundstage: A good tune would be a lead vocal with a couple of guitars/piano and some drums. Or an ensemble of Indian classical.
- The vocals should be near center, very mildly louder than the instrument set, but should not sound dismembered.
- Drums should sound as though they are being heard from slightly behind the singer and the other instruments with the vocals
- Move a foot or two to the right or left and one speaker will be heard more than the other. Note these changes
- Move a foot or two towards or from the speaker plane and the perceived depth of vocals/instrumentation may change. Note these changes.
- Sometimes it feels everything is coming from the speaker plane, sometimes I can hear depth. I feel a bit of depth is good.
- Indian classical or hindustani music is a good idea to check out because of fewer instruments.
3. Bass/drums etc should be as tight and precise as possible. There should be no boom or reverb; if so then the room is contributing more than it ideally should towards playback. Tabla playback, I feel, is very good audition material. Boom or reverb can give you a headache very soon.
4. Mids/Highs should not cause you to scrunch your face. This means the system is "bright" and needs some toning down. This can cause listening fatigue within 5 minutes.
5. Volume - increase and decrease the volume to hear how it sounds at different points. You may want to hear how it sounds at low volume as it is a very real scenario (late night listening).
6. If the speakers truly disappear (close your eyes and check), then the system is a good one and the room is not contributing too much to the sound.
7. Vendor willing, ask if the speakers can be moved in/out, closer/apart (on a first visit, it is unlikely)
8. Have another person with similar music tastes to get a second opinion.
9. Once you narrow down on a system, come back home and try to judge how it may sound in your imperfect setup. Make the decision after sleeping it over.
Hope this helps.
Cheers,
Raghu