I have recently had a pair of Rock Monitors restored/repaired from abuse caused by my brother. The pair I had were the first version with a 6 inch mid-bass, 2 active 10 inch woofers and a ducted port to the lower left of the mid-bass. I purchased them new in 1974. There are 2 other versions of ESS Rock monitors - one is like mine but without the port, and the other has no 6 inch mid-bass and one active/one passive 10 inch woofer. What is the big difference in these 3 different designs and which one is the overall best for frequency response and 'quality' of sound? One more thing, the speaker badge on mine is ESS AMT 3 and the others are ESS Monitor.
Different Versions of ESS AMT-3 Rock Monitor
- Thread starter joe_tex
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Porkloin
Oscar Heil Groupie
Find someone with a digital camera and get the photos of those things on here, unless they're still with your buddies up north that are doing God-knows-what with them. And a listening report - AK member Audioscout is looking to lay hands on some 1040's and would probably appreciate a bit of feedback.
The unique part of the AMT3 is the transition (6") driver. I'm not sure why ESS didn't bring that forward into any of their new models. A cool feature of some of the old AMT1 Monitors was a crossover that you could bi-amp with without taking the speaker apart and getting creative with a pair of dikes. Given the choice between the two, I'd still take the AMT3's. If I was that interested in biamping, I'd by the gear and tri-amp mine.
All other things being equal, I'll bet there's little difference in sound between the sealed version and the ones with that tiny chunk of paper towel tube commonly referred to as a port. I suppose you could have someone shove a piece of foam in and out of your ports while you did a blindfolded listening test - I'm curious what the outcome would be.
The unique part of the AMT3 is the transition (6") driver. I'm not sure why ESS didn't bring that forward into any of their new models. A cool feature of some of the old AMT1 Monitors was a crossover that you could bi-amp with without taking the speaker apart and getting creative with a pair of dikes. Given the choice between the two, I'd still take the AMT3's. If I was that interested in biamping, I'd by the gear and tri-amp mine.
All other things being equal, I'll bet there's little difference in sound between the sealed version and the ones with that tiny chunk of paper towel tube commonly referred to as a port. I suppose you could have someone shove a piece of foam in and out of your ports while you did a blindfolded listening test - I'm curious what the outcome would be.
Porkloin
Oscar Heil Groupie
I see a bunch of pictures of variations out there, but the only published schematic I've ever seen is the one below.
Joe_tex here. Well, you can take the tex part out of my name. I used to work in the oil industry as a geophysicist, but got the ax this past May. I am too old to ever be considered for employment again, so I am considering moving back to Virginia some time between the remainder of this year and next summer. My AMT-3's are still back at my buddy's place in his pond house. He has a 200 acre farm with a large pond. He has only used them a couple times and no one else wants them. They are too big and too heavy and no one wants the cops showing up at their door. My mom is 90 and lives alone, so I may end up moving back with her to help out around the house. She does not want any of my stereo gear in the house. I have several monster receivers (165-185 WPC range) and always wanted to hook up 2 pair of these and blast them as loud as possible. The pond house is the only viable option. If I do buy another pair, it will be the AMT-3 version, with the 6 inch mid-bass. I need to have that experience 4 speaker experience for no particular reason.
crispycircuit
Super Member
Put them in Barter Town and let someone enjoy these beauties. Good luck with mom.....
Porkloin
Oscar Heil Groupie
Sorry to hear that Joe. I feel your pain. I had to go into business for myself as hiring departments don't like old gummers walking through the door. As it turns out, clients do.
I hope your buddy in Virginia has the wherewithal to hold on to them for you. Who knows, maybe you'll get a life change that will allow for you to keep them.
I hope your buddy in Virginia has the wherewithal to hold on to them for you. Who knows, maybe you'll get a life change that will allow for you to keep them.
On a quest
New Member
Does anyone know if the ported version of the AMT 3 with the 6 inch midrange have the 680-0010 woofers or the 679-1111 woofers. I am trying to restore a pair of Rock Monitors and was needing some information on the differences between the two versions. The four 679-1111 woofers I pulled out of two cabinets that this guy was parting out (ported version) are original to the cabinets but all four measure 3.3 ohms and in parallel obviously are under 2 ohms. I was wondering if the ported version was hooked up in series with the closed box version hooked up in parallel. All the schematics that I've seen out there have two 680-0010's in parallel and they just don't matchup with what I see in my cabinets. I did see another gentleman (Lacrosplayer) post some pics of his Rock Monitors along with the crossovers in the cabinets and they are the exact ones that I have. If you are still around Lacrosplayer and hopefully you still have the speakers I was hoping you and I could help each other out. What makes this problem worse is that the cabinets I pulled these woofers from were left up in Maine because of lack of space in our SUV on our trip back to Jersey. They are stowed away in my brother's basement but it makes any comparisons between the four cabinets pretty tough. Any and all help from anyone in getting these classics back to their original glory would be MUCH appreciated.