ESS AMT-3 Rock Monitors from Down Under - Oz

[automojo]

That's what I was looking at the last spec
It performs all right in bass box pro there's a slight rise that needs probably have to just the crossover accordingly and have a heavily stuff box
The problem with the 1040s is they had a serious midbass rise that you had to correct with a Zobel
Even when you plug the port it didn't make a difference the stock set up is more or less a leaky sealed system
And I'm sure you could get eminence to make the 1040 SF or the Dayton's if you ordered 50 drivers that's their minimum
Misco located in the Minneapolis according to their new website can build you anywhere from 1 to 10 drivers so that could be a possible option I'm sure it's not cheap but then you can get a perfectly designed woofer for for the AMT3
I had always thought about approaching them but the Dayton seemed to be a easier option i'm probably a lot less expensive but you never know unless you check it out

 

[Porkloin]

How is that fourth coil incorporated into the crossover? Three is enough to have a second order for all of the drivers and/or a third order on the tweeter. Do they divvy up duty for the woofers or go fourth order on the Heil? Any schematics?

 

[automojo]

No schematics
I'm assuming the two large inductors with the resister pack between them and their placement means they wanted them coupled together inductively
When I got these the woofers of been recently refoamed and actually sounded better than the three coil crossover
I think these were the crossovers design by Nelson pass or when he was involved because the serial numbers are really low on the speakers 200 and 600
They used 4 ohm woofers 4 ohm peerless mid range with a rubber surround
Cactus Bob has a set of these that he put 4 ohm Polk woofers in- as they had Pyles
In hindsight maybe I should've kept this set stock they were better but not as good as the Dayton's as I recall I didn't listen to them for that long before I started tearing them down

 

[automojo]

To me the crossover was just overly complicated
I like the simplicity of the three coil crossover
In my opinion you use enough components to get the job done but not anymore so if you can get the job done with less components that's a good deal
I'm sure the reason they moved to the three coil crossover had to do a cost
I'm sure they were using the 4 ohm woofers first because they were higher output
The reasoning of the extra components probably has to do with the drivers response characteristics-so unless you have those woofers I think it's pointless trying to copy it
But if you compare the later model foam edge mid driver to the Peerless- the foam edge one has a bigger voice coil larger X max. Also used a larger mid tube and was attached with black silicone and 2 screws that pushed down on the flange
I can't recall the woofers but they were more or less the same as I recall

 

[automojo]

Now all you need to do save your pennies for a new SAE 2HP-D
What an awesome amplifier
Uses some novel circuit design- i'm a little different route than the H/K PA-2400 trying to combat the same types of distortion and faster slew rates and rise times and ultra low signal to noise ratio's
That's the one thing that still blows me away about the PA 2400 is the background is completely black
You just don't see amps with 120 DB signal to noise ratio anymore
Nice to see someone actually still cares about amplifier design without trying to design a certain sound- that's what speakers are for
And not cheaping out with a class D design.
I for one get tired of reading about reviews on those I just don't like the way any of them sound- so far anyway
To me they are sub woofer amp's
It's the new efficient way of amplifier design but I'll stick with the AB's
To me alot of those class D amps are like the emperors new clothes they should be an inexpensive but they charge through the nose for them
I don't think you're getting any value or should I say sound value!

 

[Porkloin]

Is anyone of notoriety using Class D amps for Hi-Fi? I thought that's how they got a kazillion watts cheaply into Pro Amps.

 

[automojo]

Lots of new "hifi" I am seem to be using them lots of reviews in Stereophile.
Or hybrid class d
In my opinion they don't seem to be quality watts- they generate a lot of noise in the 400kHz range that needs to be dealt with
Theta sells a class D for 12k
I think Mark Levison has them
I'm sure the 12 K one sounds fine well you better hope so
Anyhow that's why I've always stuck to HK amplification because they are always built on the same theory -fast slew rates wide response and low noise, and low distortion without a lot of feedback
yes they sound different between different models but you're still getting the general "base" sound.
Most run a high bias and run warm so they need repair or at least checked out after many years but it's a small price to pay my opinion
Plus most of the time they are dirt cheap compared to a lot of other stuff
Lots of H/K bashers for this reason or that reason usually the quality control or some of the the odd ergonomics etc
To me the bottom line is the sound the other stuff you can deal was with a few minor repairs
Into me one of the big advantages it's a constant in your system- A consistent sound and response so it's much easier to choose your supporting cast of components without making a major mistake
Plus their larger amps have the abilty to drive any speaker you might choose particularly in the bass department they have excellent bass drive damping and control so there's no worries there
Makes life a lot easier in my opinion
I was sold on them at a young age my dad's kit built citationII and citationv
The only tube Amps I can recall that had excellent bass drive with clean sounding mids and highs that were not rolled off
And were actually fairly quiet for tube amps
They actually sounded like a good solid state amp should sound
No fake tubey amp designer sound that makes it so complicated to find a supporting cast of components

 

[Porkloin]

Why is it that even well respected individuals here engage in the pissing contest more commonly referred to as "My speakers get way low"? Common physics would dictate that a larger enclosure with more cone moving back and fourth a greater distances translates into lower woof, and yet mathematics says that my large drivers in a big box gets down to about 47 Hz, while owners of smaller speakers I've A/B'd against the Rock Monitors are laying claim to sub-30 numbers. Even the Automojification Version 2 enhancements at 38 Hz are still up there with Minimus 7's according to "conventional wisdom". I know that the other speakers don't shake the guts or alert the neighbors as good as mine, not that I'm striving for the same thing that the kids in their non-descript little Japanese coupes do. I've got my components hooked up such that the tone controls are bypassed, so I'm not augmenting the bass in any way. The overall tone is balanced and lacking in bass only to the abovementioned Toyota drivers and people that have acclimated to a poorly tuned subwoofer.
Are we caught up in some sort of silliness with its Genesis in the brains of manufacturer's ad writers? How often are these numbers verified by someone other that a freelance reviewer grateful to the manufacturer for sending stuff over for them to play with?

 

[automojo]

Well I finally got my F mod 30 Hz high pass
It completely eliminated the woofer flutter
As mentioned I have my port tubes cut at 6.1 inches
So there tuned a little bit lower
It's interesting to play with taking them in and out
But the Dayton's sweet spot for clean bass is about 30 Hz max
They definitely have response below 30 Hz but it's not very clean
Dayton lists 35 Hz up as the ideal range I would say 30 Hz on up is the ideal range
If you had yours tuned higher you probably wouldn't necessarily need them unless you're playing a lot of LPs
you're probably still getting some sub sonic material that needs to be cleaned up it's just a complete waste of power and you risk damaging the woofers at high levels
The F mods are great little devices and work as advertised with no side effects I can hear
I agree I have no need for tone controls the way they're set up but it's still nice to have them
Say I happen to be listening to a football game on the radio I turn the controls all the way to the left
I've read many of the hundreds of threads here on the argument of using tone controls or not
To me it's simply a matter of taste no right or wrong here and not worth much discussion in my opinion
They using tone shaping in recording live performances etc- so I don't see the big deal if you like using them or need to

 

[Porkloin]

Well I finally got my F mod 30 Hz high pass
It completely eliminated the woofer flutter
As mentioned I have my port tubes cut at 6.1 inches
So there tuned a little bit lower
It's interesting to play with taking them in and out
But the Dayton's sweet spot for clean bass is about 30 Hz max
They definitely have response below 30 Hz but it's not very clean
Dayton lists 35 Hz up as the ideal range I would say 30 Hz on up is the ideal range
If you had yours tuned higher you probably wouldn't necessarily need them unless you're playing a lot of LPs
you're probably still getting some sub sonic material that needs to be cleaned up it's just a complete waste of power and you risk damaging the woofers at high levels
The F mods are great little devices and work as advertised with no side effects I can hear
I agree I have no need for tone controls the way they're set up but it's still nice to have them
Say I happen to be listening to a football game on the radio I turn the controls all the way to the left
I've read many of the hundreds of threads here on the argument of using tone controls or not
To me it's simply a matter of taste no right or wrong here and not worth much discussion in my opinion
They using tone shaping in recording live performances etc- so I don't see the big deal if you like using them or need to

Actually, I have nothing against tone controls. They just don't happen to work on my preamp using the DIR1 input. If I ran RCA cables and switched the source on the preamp from DIR1 to CD or Aux, they'd kick back in.
It may be worthwhile inserting a pair of those in and switching back and fourth to see the difference. If I don't have one of those nasty old turntables hooked up, what is the source of sub-sonic stuff? I have no pipe organ recitals and probably not that many concert grand piano recordings that get played that often.
I wonder how tough it would be to DIY those doohickeys and what would be the complications associated with balanced connectors?
ADDENDUM: What would be the harm in setting up a DIY passive line level crossover at the frequency that Bass Box says my setup is operating at?

 

[automojo]

Yeah I'm not sure on the DYI crossover
The F mods are cheap and work well
I don't have a turntable hooked up to the system either
I just noticed the woofer flutter at high volumes with program material that had lots of low bass information
The sound can be interesting at lower volumes because you're getting that lower bass response but at higher volumes it sounds kind of muddy at certain levels:frequencies and not the cleanest
Personally I think a lot of this is just movement and they're not really reproducing some of these low frequencies at useable levels
So all in all a waste of power and not a good thing
The Daytons are trying to reproduce this information but the combination of the box tuning and their designed response limitations is probably why I'm
seeing this
You can experiment yourself and see what happens
Paul Simon late in the evening is one track I noticed it for sure as one example
Another excellent track is by Blake
When the stars turn blue
Fat low bass
I can appreciate different types of tuneful bass- I think in part was me being a fill in bass player back in the late 79's early 80s-by choice I had way too many things going on back then to be a touring person
That was another lifetime and firmly belongs back in those times I enjoy listening now- but just an explanation of different types of tones I like with certain tracks certain levels even certain times if that makes any sense
Overall the sound is tight detailed with plenty of bass with the F mods- and not over emphasized or muddy
I think a lot of this change is the combination of my particular box tuning the breaking in the woofers and all the components and damping material I probably have 60 to 70 hours on them and this is just the fine-tuning
Maybe in your case with the higher box tuning you wouldn't have this problem as mentioned
I'm not shortening up my port tubes- I will use the F mods and have an interesting different sound if I want to by taking them out
I think another way around this would be the stuff the box slightly more - something I didn't want to do I'm happy with the damping I have right now
That's the whole point of the F mods it's to help you with small issues without making a big production about it inexpensive and easy to use
Even if you don't have a separate amp and preamp he can run them through a tape loop on in line with your CD player etc
But again the lesson might be here to tune them a little bit higher- I went around with this a few times but U ended up with the 6.1 because I liked the sound better overall- and I think if I shorten them I wouldn't like it
I don't think there's any right or wrong here there's more than one way to achieve your desired results

 

[automojo]

And remembering recommendations from Parts Express plus a couple other contributors recommended in a number of different box tuning schemes using a sub sonic filter
Probably in part because of what I've been experiencing - and also power handling

 

[brianjrealto]

I have a pair of the 2-way monitors, biamping terminals as well. A while back, I biamped my pair with 2 amps, an active crossover and all the cables necessary to make it work. Cabling was the most time consuming in finishing the biamp setup...

What I discovered was very interesting... The sound quality improved somewhat because of the efficiency. But, I realized that the original caps in the ESS crossover were better than I expected. I assumed the original crossovers needed recapping due to age. But, biamp in proved me wrong and I realized these ESS crossovers were tight, sounding as good as biamping, but less efficiency as expected in heavier passages of music playback.

 

[Porkloin]

I have a pair of the 2-way monitors, biamping terminals as well. A while back, I biamped my pair with 2 amps, an active crossover and all the cables necessary to make it work. Cabling was the most time consuming in finishing the biamp setup...

What I discovered was very interesting... The sound quality improved somewhat because of the efficiency. But, I realized that the original caps in the ESS crossover were better than I expected. I assumed the original crossovers needed recapping due to age. But, biamp in proved me wrong and I realized these ESS crossovers were tight, sounding as good as biamping, but less efficiency as expected in heavier passages of music playback.

Which leads to the eternal AK speaker forum question: Electrolytic or Poly?

I had caps that measured between 10 and 30% out of spec when I replaced them (with poly-caps) "just because" they were aged. Was the notable difference in detail, presence and nuance because of the newness or materials of construction of the capacitors.?

 

[automojo]

Sure
I think if you had a true a/b blind testing I highly doubt anyone could tell the difference
My first pair of AMT 3's I rebuilt the crossover with electrolytic caps and it sounded just fine
And I still have that crossover and don't plan on doing anything with it
I tested all the caps and they were right on spec
I got these from Erse and they were the tighter tolerances electrolytics
And be aware that when ESS designed the crossovers those caps had a 5 to 10% tolerance so they designed that with in mind
What I did notice is that at high volumes you got some distortion because I'm
sure I was exceeding the caps power rating-it wasn't driver distortion.
I think if you had higher rated electrolytics they would be fine
The main advantage of rebuilding the crossover is making sure you dont happen to have a thats going out of spec
Each beaker is going to be different because of environmental exposure and how hard they were driven in the past
I've had two AMT3 crossovers now that I've bought used that obviously were overdriven one had a serious burned out resistor and burned the circuit board - along with a near exploded cap
I think the other advantage is this touching retouching all the solder connections
In my opinion it's more of a preventative maintenance than anything
If these crossovers were only a couple years old I personally wouldn't touch them- but given their 40+ years old and who knows what life they've been through it's worth while to do a rebuild in my opinion
Yes it's a pain but once you get it done it's done you don't have to go back in there- or risk having a component failure and taking out your Heil etc. like I'm sure the burnt crossover I had did
The advantage of using the Polly's is it's a one and done thing
Also there's plenty of literature that's been written on how good polys/metaltzed caps are more linear in certain applications then electrolytics under load/heat
The new electrolytics are more stable and I'm sure they'd outlast me but my thought in these last rebuilds was I'm going to go all out regardless and make sure my sound is consistent and tight
I don't want to have to go back in there
Plus with the hardwire crossover I like the idea of a wide-open low ESR design
Reducing the resistance in your crossover just makes your whole system more efficient- if you get higher output out of your drivers that means you've done a good job - and power isn't wasted
Kind of like tuning up your car and checking your air pressure in your tires yes it will get you from point a to point B and it might seem to drive just fine but you're not doing it as efficiently as possible