Maybe I'm crazy, JBL 530 vs DCM..

Just received my JBL 530s, on sale.

Tremendous, mostly clean bottom on these little guys. Now to be fair, I've had them less than a day, not sure what appropriate break-in time is. 
Initially they sound smooth and piano is especially nice (' Love over Gold').

But I'm hearing a slightly thinner but livelier more open sound from my 30? Year old DCM CX 17s. Probably about as diametrically opposed design-wise as 2 speakers can be.

I had a bad experience a few years ago with another pair of Chinese made speakers, Chane 2.4s. These JBLs are better to my ears, but do I need to run them for a week and then compare, or..?
Amp is wired 4 sound sti 500. Source is CD player. Thoughts for an old newbie? Thanks

Give them at least 50 hours of playing time if brand new.  Usually as the speaker breaks in, the thinness in the upper frequency's and the bass response smooths out. 
The low-frequency driver is stiff, you need to soften its suspension as stereo notes above. You can download free warble tones etc to play (NOT loud!) to speed up the break-in process.
The 530s are great speakers, they should sound faster and more dynamic than your DCMs — which were great little speakers in their own right.
Thank you, guys, I will do that. This morning I put on ' crazy baby' by Joan Osborne, and I'm hearing open airy snare drums on the DCM, and a more cupped snare but stronger bass line on 530s. Maybe just dramatically different voicing. I'll give it a week or two.
Definitely pass final judgement only after some break in with most any new speakers. 
Let the new speakers break-in before passing judgement. To speed up break-in try to let them play when you are out of the house, or over night if you can isolate them from your sleeping area. 

To reduce the volume, while still breaking them in, wire one of the speakers out of phase, face the speakers directly facing each other, and as close together face-to-face as possible, without touching, and cover them with thick blankets. It will greatly reduce the perceived volume by cancelling out much of the sound. This allows you to break them in much quicker than just listening to them. 
@sifter  - As long as you can get the speakers really close together (without touching) and face-to-face, it should work. Just make sure you only wire one of the speakers out of phase (+ to -, - to +). The out of phase signal will cancel out a good percentage of the total sound output.

Can't hurt to try it. I've done it many times over the years, to speed up break-in and allow me to run my system around the clock for a couple of days to speed up break-in. Can't say if it will work with your horn loaded speakers, but don't know why it wouldn't work, unless you can't get the face of the horns close enough to each other to have them effectively cancel out the output signal.
Big KEF fan here... I sold my KEF LS50s because the JBL studio 530s just sounded better to me.