My first little comparison. The C710 and the JVC/Victor NX55.
The NX55 is the neckstrap version of the FX55S. The FX55 was the first JVC in-ear AFAIK and for sure their first released in the US. It was my first ever canalphone. The FX55S is a cable change a Gumy material change from the original FX55. My contention is that it is their second best phone behind the FX500.
The Denon is a more sensitive phone, 16 Ohm/110 sensitivity while the NX55 is 32 Ohm/95 sensitivity.
The Denon signature is more bass, more bright and extended treble while the NX55 has less bass and treble presence making the mids a bit more in your face. The soundtages are presented different but the image size is almost the same. The NX55 has more separation with more air around instruments and between vocals.
These are interesting earphones. Both try and mimic a larger headphone sound pretty well. Some nice reverb, good placement and distinction between impact of bass notes, decent imaging/depth overall and a large soundstage.
The Denon is a bit crisper and has more detail and treble presence/extension. I don't feel feel they really are that much ahead of the Victor though. Listening one after the other is fairly competitive. The more refined Denon versus the Victor which does have more forward vocals that are a bit more syrupy and sweet. I used to listen to the AKG K401 and the FX55 and for sure most all the Victor/JVC phones have pretty sweet mids(except for the DX1). The bass seems to go as low on both earphones but the NX55 has less bass with a quicker decay down low. At times a bit more punchy on the attack and a bit more agile. I might prefer the Victor staging the bass behind the vocals a bit more.
Overall, these are two of the more enjoyable earphones I have come across. Different but both aggressive, quick, large sounding with engaging bass and mids. The Denon has better objective SQ but subjectively they are near equally enjoyable to me.
The second comparison is the C710 vs. The CK10
Well, the Denon is a lovely sounding phone. It does fall a bit short of the high end though. My CK10 which I run with an S-adapter and E2C black silicones is a clearer window into the music. The Denon sounds a bit veiled in comparison. The soundstage is slightly smaller. The CK10's greater separation and air help make the Denon seem smaller sounding also. The clarity is high end and the transparency is noticeably better for the Technica. The overall frequency range is wider for the CK10. The Denon sounds a bit slow and sluggish after listening to the CK10 first. The C710 is not really outclassed but beaten in most aspects. You can't go right away from one to the other like the NX55 and C710. Some time needs to be spent away from the CK10 and then the Denon will sound better.