Review: Green Mountain Audio Eos vs Callisto Monitor

Category: Speakers

I took advantage of an opportunity to upgrade my Callistos to the newer (and more expensive) GMA EOS. After spending more than a year with my Callistos and enjoying every minute, I felt some reluctance letting them go. It was a bit difficult for me to think that the EOS would be a big improvement over these very enjoyable speakers. I was in for a shock. Roy had explained the differences and actually painted a very realistic, if somewhat downplayed version of what I should expect from the EOS.

I spent a good deal of time reviewing my favorite music before the Callistos were sold. I was really ready to miss them. When the EOS arrived and I hooked them up, I was blown away. I plugged them in to the exact system and position as the Callistos. Roy even advised that I would not need to re-adjust my subwoofer settings, since the sensitivity and response were so similar. I run flac files through J-River using Ayre equipment. I have a large selection of Redbook and a fair amount of 24 bit recordings with a few 24/192 selections. All of the qualities I liked about the Callistos were still present but with noticeable improvement across the complete spectrum. Whereas the Callistos disappeared in the room, the EOS floated the music in three dimensional space and transported me into the performance. One of my favorite recordings is a Channel Classics recording of Rachel Podger playing the Bach violin Sonatas and Partitas. As soon as the mic came on, I could feel the presence of Rachel in the recording booth and sensed the space around her. The position and clarity of instruments is pretty amazing. Guitars and piano sound incredibly realistic and exist in space exactly where you would expect them. On “The Last Recording” by Horowitz, the position of the piano and microphone are clearly discernible and at the appropriate height. I would not have believed the difference in these speakers unless I had heard it.

One of the improvements that surprised me the most is the quality of bass with the speakers. As an ex-professional bassist, bass quality is obviously pretty important to me. Roy explained the differences in the ports so that I anticipated some minor improvement. The EOS really deliver a much richer and punchier bass that the Callistos. String bass sounds more even and articulated throughout the entire range of the instrument. The other huge improvement came about because of the design of the tweeter. The ability to move the tweeter to set the time alignment allowed me to adjust the sound to my listening position in a precise way. The Callistos did not provide the same precision. Having the tweeters adjusted exactly allows vocals to be incredibly clear and distinct enhancing the three dimensional quality of the music. Nearly every recording I listened to sounds more distinct and brings up the clichéd report that I am hearing new detail in all of my music, maybe a cliché, but true. I feel like a kid in a candy shop, going through every recording and hearing them all for the first time again. It is hard for me to pull myself away from listening.

Roy achieved something pretty special with the EOS. The ability of these speakers to transport you into the performance is uncanny. If you have enjoyed your Callistos but are ready for an upgrade, I highly recommend the EOS. He also claims the HD version is even better. Hmmm, maybe I should get the HD’s? . . . (to be continued).

Associated gear
J-River on Windows 7
Ayre QB-9, AX-7