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Green Mountain Audio Chroma HX Review

I just had my Green Mountain Audio Chromas upgraded to Chroma HX. The difference is the crossover, with the capacitors being exceptionally high-grade. The low-pass filter is specially made to Roy Johnson's specifications. Unobtainium (not for sale) Litz wire is used with the latest unobtainium solder. The change is dramatic enough to consider the HX a different speaker, even though the schematic is essentially the same.

And the result is absolutely stunning. I was expecting a substantial improvement, but I was unprepared for the result. It's going to be difficult to put this into words, but I'm going to try. Let's face, we've heard it all before.

I have never heard a speaker that so effortlessly plays music. Every note has more music in it. I guess you could call that greater detail, but the HX transcends that description. Perhaps I should call it harmonic richness. The sound is unbelievably accurate, yet musical, throughout the frequency spectrum. The copious bass digs down deeper while being more well-defined. I would call it high-definition bass, to coin a term. The midrange is similarly tuneful, clear and also hi-def. It just flows naturally and cleanly. I would describe the treble as ethereal, sparkly and airy, never bright.

The HX is also the most coherent speaker I have ever heard. The woofer and the tweeter coexist happily. It is impossible to tell where the crossover frequencies are. You cannot hear the port either, just the bass. I find myself listening for hours, without fatigue, because the music captures my attention and holds it.

The sheer accuracy seems to lend itself to the soundstage, imaging with pinpoint precision. You know where every voice and instrument is at all times. This is an area of audio that I didn't much care about previously, but I cannot ignore now.

Any criticisms? Well one, maybe. If you like to crank the bass hard enough to drive your neighbors to yell death threats, you're going to need a powered sub.

I have heard many speakers in my time, among them Wilson Audio, Joseph Audio, Paradigm, Triangle, Meadowlark, Dali, Thiel, Usher and Vandersteen. None of them can deliver what the HX can. It's not even close. If you have a pair of the already excellent Chromas, HXing them is a must. I have found the speakers that I am going keep for life in the Chroma HX.

Related equipment:
Musical Fidelity A308cr with upgraded clocks
Audio Note Kits DAC 2.1
Pass Labs B1 buffered passive pre modified for shunt volume control
Pass Labs Aleph 3 power amp
BPT BP-1 balanced power conditioner
Audio Magic Matrix Mini power conditioner
Pass Labs Aleph 3 power amp


dave122
kenjit
1,771 posts
 


The green mountains use no baffle step compensation, highly resonant cabinets which ring, very cheap parts and are highly overpriced for what you get.
do you expect us to believe there’s not even one better woofer that money can buy than a 5 dollar car woofer?

The woofer is mismatched which is why you get poor bass. You need a bigger cabinet, or a different woofer. This is basic speaker design 101. Every bookshelf speaker I’ve heard or owned has deeper bass than the green mountains. No speaker has sounded as cold as the green mountains. This is mentioned even in the reviews. The crossover IS improperly designed because there’s no baffle step compensation and too much energy going into both drivers which is why 99% of speakers don’t use first order. The tweeter has no impedance correction either so youre not even getting a first order roll off over most of the bandwidth.
Instead you get a severe hump at its resonance frequency which you can hear if you play the tweeter on its own. Green mountain do not send their speakers to be measured by reviewers so it’s impossible to know how they measure. But measurements don’t give you the whole picture and may hide any problems with the design.
You would need a blind test where you listen to green mountain alongside yg acoustics, wilson audio, dynaudio, magico etc then I’m sure you’d hear which speaker was inferior or superior.
Unfortunately despite being around for many decades green mountain audio is not widely distributed by all the hifi dealerships so it’s very unlikely that an opportunity to make such a comparison would arise. The dealerships that carry green mountain do not carry the big names like yg acoustics, but only other less well known boutique speakers.
If you look at what else is available you can quickly see that green mountain are indeed selling you an overpriced product.

The coloration of the speakers is so bad that it’s easily heard by listening to the YouTube video I posted the link to.

The knuckle test clearly shows how badly the cabinet rings right in the midrange. Putting your ear against the cabinet reveals further ringing only on certain frequencies.

The baffle is so thick that there’s no room for the woofers rear wave to escape freely.
This is all very poor design.
kenjit
1,771 posts
 
Is there anybody here who has heard these speakers and not liked them? What were your reasons?  I'd like to see if they're the same reasons as mine.
Ag insider logo xs@2x
tsugury
251 posts
 
I have spendor's in the living room, psb's downstairs, and Europa's in the bedroom. I love the sound of my GMA europa's. To each his own, good luck finding that perfect speaker.
mindlessminion
99 posts
 
@kenjit I have owned 2 sets of GMA and liked each, still owning GMA EOS HX. I have also owned Gallo 3.1, Celestion, Klipsch Forte 1, Klipsch Chorus 2 and currently own modded Klipsch Cornwalls.  My friends have had Zu, Joseph audio and von schweiker (quite familiar with these) - plus heard many other at shows

I like the detail of GMA and for monitors they are some of the best I have heard at their price point.

Again - if you dislike them I really encourage you to find speakers that you do like, instead of continue to love the speakers you hate.   I suggest possibly Harbeth if you found GMA harsh.  
kenjit
1,771 posts
 

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
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