The driver used in the green mountain Eos/Rio/chroma is the Aurasound ns6 255 4a 4 ohm version. They claim it's customised but it looks identical.
I found a discussion on a DIY site about these drivers.
www.avsforum.com/forum/155-diy-speakers-subs/1421821-aura-ns6-255-8a-they-any-good.html?t=1421821#/t...It says: "For bass, a large ported box (1.3cf or so) and tuned to 40hz works nice."
The green mountain chroma is about 12 litres? Can somebody confirm the exact volume?
If so that's about a third of the required volume according to the simulations done by those guys.
So what happens if you stick it in a smaller box? Higher f3 and poor bass transient response. Which is the antithesis of green mountains claim of time coherence.
The tweeter used is SEAS H1462-06 27TDFNC/GW.
SEAS recommend a minimum crossover point of 2.5khz second order so it's being overworked by using a first order. Its impedance from 2khz to 750hz goes from 5 ohm to 13ohm so you're not getting a first order slope because the tweeter starts rolling off and the impedance rises. The 1uf zobel across the tweeter does nothing to correct the impedance hump. Is it a coincidence that the 750hz resonant frequency of that tweeter is one of areas of the frequency range that I hear peaks on certain notes?
The woofer has a 0.21mh coil which gives you first order electrical lowpass slope at 4ohm at 3khz but once you put the woofer in the cabinet, you won't be getting first order acoustic slope with a single coil.
Incidentally the values chosen for the tweeter zobel and woofer filter are the exact values that you get from an online calculator which suggests that no effort has gone into calculating them by measurements.
The importance of chamfering the baffle is greatest when the baffle is thick as in the green mountains. Similarly woofers should have very open baskets to miminise obstructions to the rear waves. In light of this, companies like b&w use drivers that have open basket designs. The aurasound woofer uses a resonant stamped frame which is not very open. The situation is even worse because it sits inside a thick baffle that surrounds the woofer from the rear.
No other high end speaker uses these parts based solely on their performance. It's bizarre to suggest that there are no better parts than these. I've seen high end tweeters and woofers with far greater extension than the aurasound or SEAS.
All the above are ommissions or mistakes that justify my view that the green mountains are not well designed
