ESS AMT, 3-way custom build and active vs passive crossover
Mar 6, 2016 10:50:26 GMT -5
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Post by crashdamage on Mar 6, 2016 10:50:26 GMT -5
Here's a shot story about my long experience with these extraordinary drivers and how I gradually ended up tri-àmping them. I ppsted this before but in a 4 year old thread so I don't think it got much visibility.
Well, there was 3 points I was trying to make with my story. I was hoping to stir up some good discussion in all 3, or at least 1 of them.! Please, I'd really like to hear you comments, Google bad of otherwise.
1. IMHO the large AMT 1 (aka "Elite") drivers may be the best mid-high driver ever. Period.
2. Getting passive crossovers out of the pathway between the amp and speaker driver make far more difference than even major upgrades to preamps or power. IQW keep that old amp save your money for an electronic crossover.
3 The laws of physics gave not changed. For really rock-solid, accurate low bass nothing beats big, heavy boxes and big quality woofers.
I'm willing to discuss these or whatever. Just let me know what you think. I already listed my system as an example of what I put together on a reasonable budget. Let's hear more.<br/>
I.hope someone is still reading this thread. I came across it while searching for information on the ESS Heil AMT 1 and registered so I could tell my experience with these amazing drivers.
For 37 years I've been privileged to have a pair of custom built monitors using the finest high drivers ever made. Over the years I've fine-tuned the speakers to the point where they deliver truly breathtaking sound. A Mobile Fidelity 1/2 speed master of Dark Side of the Moon is a religious experience.
Let's start from the beginning...
In 1981 there was a longtime local stereo shop here in Kansas City named Audio Mart that along with the usual sort of speakers you would expect, was selling a couple of versions of their own custom built speakers featuring Heil AMTs.
When I heard them I was totally knocked out. They blew away everything else in the store in detail and dynamic range regardless of price and that included some very high-end units. I had to splurge for a pair.
These were 2-way, in rectangular cabinets about 5 feet tall, approximately 22 inches wide by 20 inches deep, constructed of 1” high-density particle board. The sides are doubled, 2” thick from top to bottom. The upper 8” of the enclosure is divided into a separate space, effectively like a short box stacked on a taller box. But the upper box was open front and rear, with only sides and a top panel. The large Heil drivers were mounted in this open space so they could fire bi-directionally.
Mounted in the bottom of the woofer enclosure firing forward is a single (Audio Mart offered a dual woofer option I passed on) Cetec Gauss 5831F 15” cast aluminum woofer with 5lbs of Alnico V magnet and 3” voice coil. These were produced from 1978-2011 but production with the Alnico V magnets stopped in 1981 with units produced thereafter using much less powerful ceramic magnet material. I was lucky and got a pair right at the end of Alnico V production and these are the much preferred version. The boxes are sealed and heavily stuffed. A very good quality handmade high-capacity 12db/octave passive crossover with upper level control and centered at 1000hz completed the package. As you can imagine, these are very heavy speakers – almost 200lbs each!
As I said, this made a very impressive speaker, far, far better in the bottom end than the very good ESS AMT 1 monitors. They were setup together in the store for comparison, but it was no contest. The big, extremely solid cabinets and massive Gauss woofers paid big dividends. Even the midbass was better with the 15” Gauss than the 12” ESS units, a surprise.
So I hauled my pair home. Always on a tight budget, I powered them with a Phase Linear 400, quite adequate power output and still kind of a sentimental favorite. And I was very happy – for a while.
I realized from the start, even before I bought them, that the design had two major flaws:
1. It needed a midbass/midrange driver. The Heil AMT was going too low and the Gauss woofer was trying to go too high. Something was needed to cover about 70-1200hz.
2. To really show off what they could do, the big Heil ants needed to get outta that hole and into the open air.
0Now the question was...how to do it. I was wise to the considerable advantages of bi-amping, so I decided to go that way. I took the Heils and mounted them on top, in the open where they always should have been. I boxed in the open upper space with 1" thick front and rear panels, which gave me a nice box to mount very good Audax 7 1/2” mdbass drivers with a cast frame and 1 1/2” voice coils. These drivers were used in some $10,000 speakers at the time which shall remain nameless. Point is, they're excellent units. The boxes are sealed and heavily stuffed.
Some slight modification to the existing crossovers matched them to the Audax/Heil combination at 1200hz. Added a smaller Phase Linear 200 amp and used Bryston crossover and all was good to go.
And go they did! This was very good! Midbass definition was way better! Male voices sounded real! And those Heils, free from their tunnels and out in the open, really sang sweet songs!
Of course I couldn't stop there. I really wanted to get the friggin' passive crossovers and all their problems cmpletely out of the way. Face it, even the best passive crossovers are bad crossovers. I wanted to use the Gauss as stereo subwoofers and improve the integration between the Audax mibass units and AMT units. I had tweaked the big cabinets to the point I thought they were about as good as they could be, even down to sound padding surrounding the mid bass on the front of the box and on top of the shelf under the AMT to cut unwanted reflections.
But I knew I could still get more from them. Part of that involved going to 18db slopes for the crossovers, impractical with passive crossovers. It was time to get serious and tri-amping the boxes.
So my present electronics are:
Denon turntable, Shure V15.
Sumo Charlie tuner “Charlie the Tuner” modded and realigned by James Bongiorno
Sumo Athena preamp also modded by Bongiorno.
BGW Model 85 35wpc high amp.
BGW Model 150 50wpc mid amp.
Carver M1.5t 350wpc bass amp.
Rane AC23 18db/octave active crossover.
No CD player. My old Marantz quit. I'm looking.
Balanced inputs/ouutputs on crossover and power amps.
BTW, the BGW amps used to power the highs and mids are little jewels, a real underrated find. Very quiet, smooth yet detailed. A high damping factor and direct connection to the drivers makes for higly accurate, clean sound. And they're built in the USA like tanks.
So to wrap all this up...Many, years of tweaking the system has paid off big-time. The now- vintage electronics are in excellent condition and feed a really clean, clear, low noise signal with range and power to burn directly to the drivers - no passive crossovers muddying up and distorting the sound.
The importance of tri-ampiing and enabling a direct connection between drivers and amps cannot be overstated. You haven't really heard the unbelievable sound that the AMT 1 and supporting drivers are capable of until you hear them direct‹connected to the power amp. I can listen for hours, even at high levels, without the "ear fatigue" other speakers !eave me with.
The dipole Heils, now set free, are simplily unmatched in detail, clarity and power I still say these are the finest high drivers ever built. Plus they're highly efficient, 35wpc is plenty. I thought perhaps I would need more, but no. I think I've covered all the bases with the current setup and won't make any significant changes for the foreseeable future.
Nothing else I have ever heard can match the combination of speed, clarity, accuracy, smooth musicality, ease of listening yet gut-wretching realism and power of these speakers in their tri-amped configuration can deliver.
35 years of happy listening!
Well, there was 3 points I was trying to make with my story. I was hoping to stir up some good discussion in all 3, or at least 1 of them.
1. IMHO the large AMT 1 (aka "Elite") drivers may be the best mid-high driver ever. Period.
2. Getting passive crossovers out of the pathway between the amp and speaker driver make far more difference than even major upgrades to preamps or power. IQW keep that old amp save your money for an electronic crossover.
3 The laws of physics gave not changed. For really rock-solid, accurate low bass nothing beats big, heavy boxes and big quality woofers.
I'm willing to discuss these or whatever. Just let me know what you think. I already listed my system as an example of what I put together on a reasonable budget. Let's hear more.
I Well, there was 3 points I was trying to make with my story. I was hoping to stir up some good discussion in all 3, or at least 1 of them.
1. IMHO the large AMT 1 (aka "Elite") drivers may be the best mid-high driver ever. Period.
2. Getting passive crossovers out of the pathway between the amp and speaker driver make far more difference than even major upgrades to preamps or power. IQW keep that old amp save your money for an electronic crossover.
3 The laws of physics gave not changed. For really rock-solid, accurate low bass nothing beats big, heavy boxes and big quality woofers.
Well, there was 3 points I was trying to make with my story. I was hoping to stir up some good discussion in all 3, or at least 1 of them.! Please, I'd really like to hear you comments, Google bad of otherwise.
1. IMHO the large AMT 1 (aka "Elite") drivers may be the best mid-high driver ever. Period.
2. Getting passive crossovers out of the pathway between the amp and speaker driver make far more difference than even major upgrades to preamps or power. IQW keep that old amp save your money for an electronic crossover.
3 The laws of physics gave not changed. For really rock-solid, accurate low bass nothing beats big, heavy boxes and big quality woofers.
I'm willing to discuss these or whatever. Just let me know what you think. I already listed my system as an example of what I put together on a reasonable budget. Let's hear more.<br/>
I.hope someone is still reading this thread. I came across it while searching for information on the ESS Heil AMT 1 and registered so I could tell my experience with these amazing drivers.
For 37 years I've been privileged to have a pair of custom built monitors using the finest high drivers ever made. Over the years I've fine-tuned the speakers to the point where they deliver truly breathtaking sound. A Mobile Fidelity 1/2 speed master of Dark Side of the Moon is a religious experience.
Let's start from the beginning...
In 1981 there was a longtime local stereo shop here in Kansas City named Audio Mart that along with the usual sort of speakers you would expect, was selling a couple of versions of their own custom built speakers featuring Heil AMTs.
When I heard them I was totally knocked out. They blew away everything else in the store in detail and dynamic range regardless of price and that included some very high-end units. I had to splurge for a pair.
These were 2-way, in rectangular cabinets about 5 feet tall, approximately 22 inches wide by 20 inches deep, constructed of 1” high-density particle board. The sides are doubled, 2” thick from top to bottom. The upper 8” of the enclosure is divided into a separate space, effectively like a short box stacked on a taller box. But the upper box was open front and rear, with only sides and a top panel. The large Heil drivers were mounted in this open space so they could fire bi-directionally.
Mounted in the bottom of the woofer enclosure firing forward is a single (Audio Mart offered a dual woofer option I passed on) Cetec Gauss 5831F 15” cast aluminum woofer with 5lbs of Alnico V magnet and 3” voice coil. These were produced from 1978-2011 but production with the Alnico V magnets stopped in 1981 with units produced thereafter using much less powerful ceramic magnet material. I was lucky and got a pair right at the end of Alnico V production and these are the much preferred version. The boxes are sealed and heavily stuffed. A very good quality handmade high-capacity 12db/octave passive crossover with upper level control and centered at 1000hz completed the package. As you can imagine, these are very heavy speakers – almost 200lbs each!
As I said, this made a very impressive speaker, far, far better in the bottom end than the very good ESS AMT 1 monitors. They were setup together in the store for comparison, but it was no contest. The big, extremely solid cabinets and massive Gauss woofers paid big dividends. Even the midbass was better with the 15” Gauss than the 12” ESS units, a surprise.
So I hauled my pair home. Always on a tight budget, I powered them with a Phase Linear 400, quite adequate power output and still kind of a sentimental favorite. And I was very happy – for a while.
I realized from the start, even before I bought them, that the design had two major flaws:
1. It needed a midbass/midrange driver. The Heil AMT was going too low and the Gauss woofer was trying to go too high. Something was needed to cover about 70-1200hz.
2. To really show off what they could do, the big Heil ants needed to get outta that hole and into the open air.
0Now the question was...how to do it. I was wise to the considerable advantages of bi-amping, so I decided to go that way. I took the Heils and mounted them on top, in the open where they always should have been. I boxed in the open upper space with 1" thick front and rear panels, which gave me a nice box to mount very good Audax 7 1/2” mdbass drivers with a cast frame and 1 1/2” voice coils. These drivers were used in some $10,000 speakers at the time which shall remain nameless. Point is, they're excellent units. The boxes are sealed and heavily stuffed.
Some slight modification to the existing crossovers matched them to the Audax/Heil combination at 1200hz. Added a smaller Phase Linear 200 amp and used Bryston crossover and all was good to go.
And go they did! This was very good! Midbass definition was way better! Male voices sounded real! And those Heils, free from their tunnels and out in the open, really sang sweet songs!
Of course I couldn't stop there. I really wanted to get the friggin' passive crossovers and all their problems cmpletely out of the way. Face it, even the best passive crossovers are bad crossovers. I wanted to use the Gauss as stereo subwoofers and improve the integration between the Audax mibass units and AMT units. I had tweaked the big cabinets to the point I thought they were about as good as they could be, even down to sound padding surrounding the mid bass on the front of the box and on top of the shelf under the AMT to cut unwanted reflections.
But I knew I could still get more from them. Part of that involved going to 18db slopes for the crossovers, impractical with passive crossovers. It was time to get serious and tri-amping the boxes.
So my present electronics are:
Denon turntable, Shure V15.
Sumo Charlie tuner “Charlie the Tuner” modded and realigned by James Bongiorno
Sumo Athena preamp also modded by Bongiorno.
BGW Model 85 35wpc high amp.
BGW Model 150 50wpc mid amp.
Carver M1.5t 350wpc bass amp.
Rane AC23 18db/octave active crossover.
No CD player. My old Marantz quit. I'm looking.
Balanced inputs/ouutputs on crossover and power amps.
BTW, the BGW amps used to power the highs and mids are little jewels, a real underrated find. Very quiet, smooth yet detailed. A high damping factor and direct connection to the drivers makes for higly accurate, clean sound. And they're built in the USA like tanks.
So to wrap all this up...Many, years of tweaking the system has paid off big-time. The now- vintage electronics are in excellent condition and feed a really clean, clear, low noise signal with range and power to burn directly to the drivers - no passive crossovers muddying up and distorting the sound.
The importance of tri-ampiing and enabling a direct connection between drivers and amps cannot be overstated. You haven't really heard the unbelievable sound that the AMT 1 and supporting drivers are capable of until you hear them direct‹connected to the power amp. I can listen for hours, even at high levels, without the "ear fatigue" other speakers !eave me with.
The dipole Heils, now set free, are simplily unmatched in detail, clarity and power I still say these are the finest high drivers ever built. Plus they're highly efficient, 35wpc is plenty. I thought perhaps I would need more, but no. I think I've covered all the bases with the current setup and won't make any significant changes for the foreseeable future.
Nothing else I have ever heard can match the combination of speed, clarity, accuracy, smooth musicality, ease of listening yet gut-wretching realism and power of these speakers in their tri-amped configuration can deliver.
35 years of happy listening!
Well, there was 3 points I was trying to make with my story. I was hoping to stir up some good discussion in all 3, or at least 1 of them.
1. IMHO the large AMT 1 (aka "Elite") drivers may be the best mid-high driver ever. Period.
2. Getting passive crossovers out of the pathway between the amp and speaker driver make far more difference than even major upgrades to preamps or power. IQW keep that old amp save your money for an electronic crossover.
3 The laws of physics gave not changed. For really rock-solid, accurate low bass nothing beats big, heavy boxes and big quality woofers.
I'm willing to discuss these or whatever. Just let me know what you think. I already listed my system as an example of what I put together on a reasonable budget. Let's hear more.
I Well, there was 3 points I was trying to make with my story. I was hoping to stir up some good discussion in all 3, or at least 1 of them.
1. IMHO the large AMT 1 (aka "Elite") drivers may be the best mid-high driver ever. Period.
2. Getting passive crossovers out of the pathway between the amp and speaker driver make far more difference than even major upgrades to preamps or power. IQW keep that old amp save your money for an electronic crossover.
3 The laws of physics gave not changed. For really rock-solid, accurate low bass nothing beats big, heavy boxes and big quality woofers.
