green mountains


I am a green mountain user, I have the chromas. I want to find out about other peoples opinions on the Eos or Rio speakers from green mountain audio?
I had the Europa speaker and was very impressed.
I say give the owner Roy a call, he is most gracious with his time and knowledge.
how did they compare with the timepiece monitors?
I don't know how else to say this ,but the Minis absolutely blew the Europa away in every regard. You may want to look at Aether Audio's Spirit 1. (recommended an amp with 200 watts with the Mini)
I sold these after 3 fantastic years. I could have lived forever with the Minis, but I wanted to try a new slightly smaller stand mount.
I am waiting to receive the Vapor Audio Breeze which I plan to pick up at Akfest in April. The Breeze lists at only $1250 in standard finish. Ryan custom builds each speaker, so I chose a custom redwood burl,curved cabinet,with matching stands. Vapor uses the outstanding Raal tweeter and a very well regarded woofer in the Wavcor.
There is a very nice pair of Volents vl2 used here, for an amazing price. I have always coveted this speaker. Read the 6moons review. I would look real hard at this monitor. They are efficient, gorgeous , amazing bass, ribbon tweeter etc...
You may want to widen your search as there are many great monitors out there, and it may be fun to try different manufacturer.Please note, I'm not saying the Rio and Eos are not fantastic speakers. In you price range I would also have a look at Fritz carbon 7 or 5, and Selah Audio.
Good luck in your search.
First of all what kind of music do you listen to?

And can you describe in more detail the experience you had with the Europas and the Eos/Rio? What were their strengths/ weaknesses? How fussy were they with positioning? What was the tonality like?

I was initially drawn to the Green mountains because of the advertised claims of time coherency which other speakers do not have. What can you say about this? Are there any qualities which are audible with GMA that are lacking in others?
I will let others with more experience with Green Mountains give their impressions. This was my first real audiophile speaker.
The way I understand it, first order crossover speakers are more crucial to place correctly, and have a smaller sweetspot. I may be wrong on that.
I think if you want better feedback you should list what kind of music you listen to, what kind of spl levels you listen to, room size, amp to be used, and if you plan on running a subwoofer.
If you love the sound of your speakers, maybe moving up the line is great move for you.
I just think there are many great options for monitors for under $2500 especially when you are considering buying used.
I have not heard the particular speakers you asked about, but I have heard and owned quite a few of Roy's designs.

Once you hear time and phase coherency done right, it's hard to go back to anything else. I currently have the Continuum 3 HDs and I believe them to be fantastic speakers. I don't think there is anything that I could afford that can beat them. Something will, for sure, but it's probably out of my reach.

As mentioned earlier, give Roy a call. He is always ready to talk about his speakers.

I haven't heard the Rios or Europas, but I owned a pair of Pico Executive HDs last year. They throw a very nice, detailed 3-D soundstage with excellent pinpoint imaging. Tonal richness and timbral accuracy is fantastic, and the sound is very smooth, pleasant and engaging.

The phase-coherent design I also liked, and I think it helped enhance the front-to-back dimensionality of the presentation. I didn't think they were any more susceptible to a small sweet spot than lots of other speakers - perfectly easy to enjoy them while sitting in a chair off to the side.

That said, the imaging and soundstage are liable to be on the smaller side. The GMA designs generally don't provide a lot of bass and aren't the last word when it comes to dynamics. They're certainly not below-average, either, but I think they lean more toward sounding smooth and beautiful, as opposed to "live" and "exciting." Mind you, I imagine that could change with a more powerful amp than what I was using.
The most important aspect of GMA speakers to me is that they sound more like performers in your room, than a just a good pair of speakers playing music in your room. Exciting is exactly how I would describe them. And bass response is world class when you move up to the flagship. The monitors will give you sufficient bass for what they are.

as a previous owner of a pair of Green Mountain C1.5i my impression of Green Mtn's products is that they are very, very good products. I liked my C1.5i very much in every regard w.r.t. its sonic characteristics. I had a powerful enough amp such that the C1.5i sounded live & exciting. I quite diagree with Cfluxa's view of his speakers sounding "more toward sounding smooth and beautiful, as opposed to "live" and "exciting" but he did add "Mind you, I imagine that could change with a more powerful amp than what I was using" & I believe that was his problem.
Besides owning the C1.5i, I've heard the Calisto 2-way in the factory + at my brother's house (he owns a pair).

like another member posted, Roy is an excellent person to talk to - very knowledgeable & very humble & like it was written before, very giving of his time. Give him a call & ask him all the tough (& I mean really tough) questions you have about his products. That's what I did before I bought my C1.5i - hrs were spent on the phone asking Roy questions about speaker design & how he approached the matter. It became quickly apparent that Roy was a goldmine of info - he actually reads the IEEE AES papers & tries to apply the info in there to his speaker design - and that he could answer my questions directly w/o beating around the bush. I learnt that his choices for material, speaker drivers, hook-up, type of glue, type of screws was all very deliberate; nothing was merely coincidental in the hardware used.

I was initially drawn to the Green mountains because of the advertised claims of time coherency which other speakers do not have. What can you say about this? Are there any qualities which are audible with GMA that are lacking in others?
Roy advertises his speakers to be time-aligned & phase coherent & there is no gimick in his statement - they are exactly what he says they are from my own experience. A phase coherent speaker is time-aligned but a time-aligned speaker is not necessarily phase coherent.
There are several other examples of time-aligned speakers such as (the now defunct) Meadowlark, Thiel. JM Lab (by making the baffle C-shaped), Dynaudio (by putting the tweeter at the bottom & the woofer on top). While all these speakers might sound great (I've heard a few of them) they are not phase coherent.
When you listen to Green Mountain speakers the 1st thing you notice is that the entire music sounds like it's cut from the same piece of cloth - there is no separate tweeter-separate-woofer effect. Also, there is no boxiness to the deep bass - the deep bass seems to be omni-present & does not seem to come from any direction; the deep bass is felt & not heard. My C1.5i went down to 44Hz so I was missing the final octave so the deep bass I'm talking about is 44Hz-80Hz. At the same time, what I found was that the mid-bass had superb tonality - I'm talking about the stand-up bass instrument where I could hear each string as it was plucked. A great test for this (for me) was track 11 from Diana Krall's "Love Scenes" CD - My Love Is. The 1st 45 seconds - can a speaker delineate that bass clearly - 'cuz the artist sure as hell is plucking each string separately but in quick succession - without muddying the bass. Muddying occurs if the woofer driver cannot start/stop quickly & you get bass overhang. The C1.5i was a sealed box bass (which I loved -w-a-y- more than any ported design I've heard even to-date) so the bass response was simply superb - just enough, not too much, not too little (like Goldilocks right). I have to agree with Cfluxa that the bass response can be light if you do not have a strong enough amp. Roy admitted that the sealed box was 1 of the reasons that the amp had to "kick" the woofer a bit harder. In my particular case I was using TARA Labs Master Gen II speaker cables & when I switched to Virtual Dynamics Nite II speaker cables, the bass response took a major leap towards the better in terms of quantity without losing the quality.
Also note that Green Mountain Audio are true 1st-order speakers i.e. they are electrically & acoustically 1st-order x-over designs. A lot of other speaker manuf use 1-st order x-over electronics but when they add this x-over to the speaker drivers the overall response becomes 2nd order because the 1st order x-over + the 1st order roll-off response of the speaker driver add together to make a overall 2nd order response. Not so with Green Mountain Audio speakers - the driver response is flat beyond the x-over frequency meaning that it's the 1st-order x-over making the speaker freq response 1st-order. The down-side to this is that you cannot play the speaker at ear-bleeding levels - the max SPL for the C1.5i was 105dB, which si very loud for home listening. If you want ear bleeding levels (like at an U2 concert) then look at other speaker manuf.
Roy shared with me some of the impedance & phase plots of his speakers (these are not published but the performance is written in words in the speaker spec sheet). I could see that the impedance response & the corresponding phase response were practically flat 200Hz - 8 to 10 KHz. Beyond this range on either side, the speakers had something like +/- 10 degrees of phase shift. This is the phase coherence of the speaker - the speaker itself contributes very little towards adding more distortion to the music signal & that's why the music sounds right & like music. There are very few speakers in the market that do this.
W.r.t. a speaker's output, lack of phase distortion is key. Always remember that, in Nature, phase is the independent variable & that frequency is the derivative of phase. If your phase response is flat, your impedance response will be flat as well.
This where the 1st-order x-over comes into play. The 1st order x-over is the only x-over response that keeps the group delay of all the frequencies flat i.e. all frequencies within the frequency band (in-band) are constant (rather than being variable like most other speakers in the market). Another way of saying this is that the phase distortion of Green Mountain speakers is very low. Other speakers that compete with Green Mountain Audio in this regard are the Quad ESLs, Apogee ribbon speakers and SoundLab ESL speakers to name a few. You can see what I'm implying here - the Green Mtn Audio speakers have a tonality & freq response that is much akin to an ESL speaker. Not an easy feat to achieve with cone dynamic drivers......
Hope that this info helps.
The best would be to give Roy a call & ask him a lot of questions that are swimming in your mind.
That was one of the best responses I've ever read here at Agon. Very well said and with good info.
Just one error though.......
Meadowlark and Thiel ARE time and phase coherent speakers.
JMLab definitely not. Only a couple Dynaudios are capable of being, and only then IF set-up very strictly speaking.
Either way. The Meadowlarks and Thiels are the one that were designed to be phase coherent.
Prdprez, thank you for your kind words.
03-28-12: Prdprez
Just one error though.......
Meadowlark and Thiel ARE time and phase coherent speakers.
yeah, I know that Thiel does advertise that their speakers are phase coherent but I do not believe that to be true hence my statement the way it was written.
Here is some proof to back up why I do not think that Thiels are phase coherent:
This is for a Thiel CS6 speaker. Look at Fig 1 which shows the impedance & phase plots. The phase is all over the place going from -45 deg at 45Hz to +22.5 deg at 20KHz & every phase angle in between. IMHO this is hardly phase coherent!
This is for a more recent Thiel CS2.4 speaker with the review done in late 2005. Again, look at Fig 1 which shows the impedance & phase plots. It's worse the older CS6 speaker as there's even more phase shift in the 20Hz-20KHz audio band!! Once again, hardly phase coherent; au contraire, it's quite phase incoherent.

In comparison, look at the impedance & phase plots in Fig 1 of an older Green Mountain Audio speaker - the Diamante. This review was done in 1998. Look how flat the phase response is in the 200Hz - 20KHz range. Very nice indeed! Now, this sort of speaker is distorting the phase minimal hence far, far more phase coherent. There is a dip in the phase to -30deg at 70Hz due to the bass enclosure (the bottom rectangular box).
GMA has a white-paper on its web site concerning time allignment and phase coherance and the relationship between the two. About half way into it, they make the point that time coherance is the condition for phase coherance-- not the other way around as mentioned above.

I recently had a two-week audition of the Eos-HX monitor. The HX reportedly reduces phase shift to +/- 1 degree across a wider frequency range than with prior Eos iterations. I liked these speakers very much-- particularly good value at their $4K MSRP.
I agree with Bombaywalla's post. Although I have not heard the RIOs, I did hear one of the last Europas at GMA and I own a pair of the first EOS made (recently upgraded by Roy to EOS HX). Each EOS is supported on LF by a GMA Hammer Lite using an Audio Control Richter Scale III low pass xver at 48 Hz, no high pass filter used for the EOS. Each of the 4 speakers are fed by ~200w monoblocks - new Hypex NCore for EOS, W4S SX-500 for Hammer. I listen mostly to acoustic music - classical, country, folk, and some classic rock and jazz. The 200 watts is much more than is needed to drive these speakers to very loud levels. The EOSs provide very accurate and realistic music reproduction, be it seated at the "sweet spot", standing 3-4 feet behind, or even in the next room (listening to a CD of the same musician playing the same Bach violin sonata on the same Strad that I heard live at a local performance while walking in the foyer of a local hall). I have no reason to change to anything else; the GMA speakers - EOS and Hammer Lite - are bargains in the current market.
Bombaywalla, perhaps I'm the one that's mistaken, but I think you might be confusing electrical phase for mechanical phase?

Thiel's previous products before the use of concentric drivers had different plots, e.g.:

BTW, for those that might not have been aware of this (IMHO, perhaps the best thread to ever appear on Audiogon):

I feel the same way as you do about my C3 HDs. Sometimes I have fleeting thoughts about upgrading to something else, then I spend a few hours with them and those thoughts are chased away.

03-29-12: Unsound
Bombaywalla, perhaps I'm the one that's mistaken, but I think you might be confusing electrical phase for mechanical phase?

Thiel's previous products before the use of concentric drivers had different plots, e.g.:




BTW, for those that might not have been aware of this (IMHO, perhaps the best thread to ever appear on Audiogon):

Unsound, no I was not mistaking mechanical phase for electrical phase.
All-the-same thanx for posting those measurements for earlier Thiel speakers. Those imp & ph plots look a lot better than the ones I posted of more recent Thiel speakers. I can see now why Prdprez posted that Thiels are coherent speakers.
So, why in the world, did Thiel depart from a good thing - his original coherent speaker design as the more recent speakers from Thiel measure worse imp & phase-wise meaning more distortion of the music signal??

yeah, I agree that thread was an awesome one. That's exactly the thread I read again & again & again & again + spoke to Roy about its contents for many hrs & ultimately ended buying a Green Mountain Audio speaker! I would recommend reading all those posts in that thread until the contents are fully digested. The reader will learn a LOT....
Bombaywalla, I can only guess why. Perhaps for cost savings, improved time and dispersion coherence, and ease of loudspeaker placement? Since it appears as though the concentric drivers use a mechanical rather than an electrical cross-over, perhaps the sum at the listening position is corrected for?
Considering what was posted by Roy in that thread, I have to wonder why there isn't more use of sealed box enclosures by the loudspeaker designers that adhere to this philosophy.?
I think ultimately somehow digital technology will make these ideas more accurate and practical.
Georger and Dgarretson, I own the chroma which is the new model and uses the same drive units as the EOS which you have.
I have not found the tone balance on the speaker to be strictly neutral. It tends to be more pronounced in the low mids. What is your opinion on the tone balance of the EOS?
Why would Thiel deviate from their superior measuring earlier designs??
Simple, this industry demands new products in order for a company to remain viable. This makes things very difficult for any Time/Phase practitioner to survive on anything but the small scale that Roy is maintaining. Case in point is Meadowlark and Dunlavy. Dunlavy came out of the gate with what is quite arguably the most accurate speaker line in the history of audio. (technically speaking) But where to go from there? And Meadowlark, their designs mostly changed with much improved cosmetics in the end. Neither survived.
There are only a small number of music lovers that actually care about truly accurate sound. (The rest are "audiophiles" aka "gear-o-philes")
The Thiel approach, no doubt, was to start looking towards marketing savvy exotic things. Joining the exotic driver bandwagon, etc.
Dunlavy flatly refused to move from the drivers he was familiar with. And Meadowlark took the route of trying to make ever more affordable designs while relying greatly on improved cosmetics and, to a lesser degree, improved performance.
But, ultimately, once you've designed a great time/phase coherent speaker you are essentially competing with yourself. There comes a certain saturation point where the anti time/phase coherent nature of the industry as a whole severely limits the gathering of new converts. And given that fact that a companies older time/phase accurate designs outperform newer "exotic" IN-coherent designs, these products are snatched up on the used market, doing the original manufacturer no good. They must rely, increasingly, on existing customers "upgrading".

On another note...
I've exchanged emails with Roy a few times and would really love to meet him someday. But I did have similar long exchanges with Pat McGinty (Meadowlark) and John Dunlavy. It's truly a very different conversation than with ANY of the other speaker designers out there. I would describe it as educational versus indoctrinational.
Kenjit, Eos moves lots of air through dual ports to achieve mid-bass and LF reinforcement uncharacteristic of most monitor speakers. In any reflex design there are inevitable trade-offs between LF extension and mid-bass and LF coherance. Eos does well in this regard, but its strongest suit is seamless mid to treble. Sitting in the sweet spot close to near-field listening the soundstage is deep and wide with exceptionally stable images contained inside less diffuse boundaries than one may be accustomed to in speakers exhibiting greater phase distortion. The experience takes a bit of getting used to, and falls into the catagory of "less is more."

While "coherant" in terms of phase response, they may not be the last word in resolution and expressiveness of nuances of timbre-- which should be no surprise at this price point. However I haven't heard anything in the $5K range that surpasses them, and their small sins can be forgiven as sins of omission rather than commission.
I wouldn't say it's a matter of mid bass to LF coherence. I am referring to the tone balance from lower mids upwards or simply the frequency response.

So in this regard what is your impression of the Eos? For example, the reviews of the Eos and Rio stated that there was an upper mid range forwardness. When I first heard the Rio that was pretty obvious to my ears, it just sounded like somebody had equalised the upper mids and boosted them. With the new chroma model, I still hear an unusual frequency response. That is why I would like other owners and people who have heard them, to comment.

If the Chroma is adjustable, what you are hearing may be attributed to that. I know I can make my C3s sound horrible without much effort. And when you get it right, it's pretty obvious. Are you sure you have them dialed in as well as possible?

I auditioned the Eos and Eos HD. I have hesitated to report on it, because the experience fell so far below expectations that I'm inclined to blame it on dealer set up. I had expected to buy the speakers, because they were an excellent on paper match with the room I had then, and Roy was so helpful. But I, and the non-audiophile friend who went with me, couldn't wait to get out of the demo. "Forwardness" indeed; I'd have characterized the upper registers as "edgy," or "brittle." I read one UK review that was consistent with my impressions.

Now I should say that I am one of those people who is overly sensitive to brightness in the highs, and numerous well-liked, highly "detailed" audiophile speakers are torment for me. But I would say that if you have this issue, it might be wise to approach the Eos with caution.

FWIW, I found the HD to be conspicupiusly better than the base model, though the my issues remained.

I should stress, since I've been a bit critical, that YMMV. As I recall, Shakeydeal went to GMAs from the Montana's I now use, and likes them much better.

Bombbaywalla, I don't think Apogee's are time and phase coherent.
For those who don't know about the Chroma:
Kenjit, I didn't sense the frequency imbalance that you describe, nor was this remarked to me by any of the 30+ audio society members who heard Eos-HX at a club meet. I have also spent quality time with a friend's Calypso HDs. On low power SETs these had good tone and frequency balance as well. However, going back in time to an earlier model on display at RMAF 2010, I do recall hearing a bit of that in the GMA room. Show conditions can of course be problematic.

FWIW, I found that the 4 ohm Eos-HX relaxed considerably on the low impedance taps of my modified 75 wpc BAT tube amp.
Kenjit, I agree with Dgarretson. The couple of nearest audiophiles I've had in for listening sessions did not remark on any frequency imbalance of either EOS or the updated EOS HX. Nor of any bass deciciency of the Hammer Lites.

Prdprez, I have spent many hours of discussion on phone and at GMA discussing details of loudspeaker design and measurement. The discussions were very informative and educational as my graduate study of physics ended over 40 years ago. I believe part of Roy's mission is in education and is very generous with his time.
shakeydeal, the chroma looks like the Rio so its not adjustable. And the C3 use different drive units so its not possible to compare with that. But yes I have dialed them in and played with the positioning. I would say they are highly room dependent. I don't know why but the sound quality (including but not limited to the tonality) can vary from one extreme to another. It's interesting what you say about making them sound horrible. Maybe its because of the shallow crossover slope they use. Thats the only common factor between the C3 and my chroma.
Jdoris, what you say is interesting, do you have an email so that we can talk about that more? thanks
I have owned the Imago IIIs, the Callistos, and now the C3s. I know jdoris likes the Montanas, and I did too for many years. But all the GMA speakers I have owned made the Montanas sound boxy, and well, like speakers.

Kenjit: You can track me down at

Huh, who'd have thunk it? Another moral psychologist on Audiogon? My PhD advisor is Rick Shweder at the University of Chicago. Shame e-mails are no longer allowed in the new Audiogon, huh? But put after my user name and a message just might get to me.
What are your thoughts on NCore? I ordered my pair last week.
Hope I'm not too late but I have owned the Europa, Europa Max and the Callisto. My friend owns the EOS HD's and previously owned the Calypso. I am intimately familiar with Roy from Green Mountains work.

With that being said, I can honestly say that Green Mountains are one of the most satisfying line of speakers I have ever owned. However, as my desire to own a more full range loudspeaker developed, the Green Mountains became unobtainable for me. I would have had to either add a sub to my Callisto's or move on. I chose to move on. There are still times when I pine for the unrivaled clarity that Green Mountains offer but my Magnepan 1.7 fit the bill for me a little better. I still believe though that there is not a loudspeaker line that offers more musical resolution and coherence within their specified frequency ranges.

Green Mountains are by far one of the most transparent and clear loudspeakers out there. They do well with medium power tube amps and solid state alike. They are not perfect but they are closer to perfect than anything else I've heard. Sure, there are warmer speakers, more full range, slightly more top end extension BUT nothing, in my opinion does most things as well as them. Vandersteen's come real close but the Greens edge them out slightly when I comes to overall clarity and transparency.

Be careful though, most other speakers sound phasey once u experience the Green Mountains. Also, Green Mountains are awfully expensive when full range is desired.

Lastly, the look is either love or hate. I was leaning more toward the hate camp.

Best of luck and buying them is never a mistake!
If you keep your eye out, some of full range GMA speakers come up from time to time. I could never have afforded my C3s when new. But I got a killer deal on a used pair that I just couldn't pass up.

Dallasjustice, I think this is off topic, but if there is a way to respond directly to you I have not discovered it.
In short, I find them extremely good - I now have 3 amps to dispose of.
Shakey, I own a 4-way system, which began life as Green Mountain Audio Imagos, not sure about the version, but that's irrelevant because only the original cabinets remain.
How do tweak these to world class performance?

Re-wire using Dueland's four nines silver ribbon inside wire or version 1.0 or so.

Move the crossovers to the bottom of the speaker (instead of in separate boxes) eliminating
connecters that rob both signal strength and quality.

Upgrade the cross-over components, and finally roll in NOS drivers, except for the current construction super tweeters. Flavor cross-over points to taste. If you use the "good stuff", allow 150-200 hours of break-in time, with a signal playing through it, before any serious or critical listening.
Hi Georger,
I own a pair of Eos HD and am astonished each time I listen to them, just how lifelike the sound is that they produce, regardless of musical genre or instrument in question. I am intrigued with your mention of Roy upgrading your Eos to the newest "HX" iteration. Can I ask what that cost, about how long it took, and what changes you noted over your original Eos in term of sound quality? I am guessing for Roy to take the trouble to release a new version, the change will likely be significant, but am curious on your thoughts after hearing before and after the upgrade.
Thanks so much,
Cporada, My EOS were among the first built and Roy had made some modifications to the crossover. In Nov 2011 I think the cost was around $800: the only things NOT replaced were the HF driver and the enclosure, and I drove them to Roy's place so shipping was not needed. I think it took about 3 hours for the total job. Differences are most notable on the LF end - better than before. BTW, since I was able to sell several amplifiers and my old speakers (Linns and Velodyne) that I replaced with a pair of GMA Chromas driven by W4S SX-500 monos - very good sound indeed, much like the EOSs - and more than sufficient for the small room where my digital darkroom is located.