The following photos and system descriptions were provided to us by one of our customers, Ellery Coffman. He has put together an amazing system and has carefully treated his room with acoustic absorbers. Nicely done!
Home Theater Featuring 10 Benchmark AHB2 Power Amplifiers
Hi Rory,
Thanks again for your help. For two speakers, it is truly unbelievable how real this tri-amp system sounds; it is nothing short of jaw dropping! It truly sounds better than the $200k+ setups I've heard in some of the high-end audio shops I've been to.
It took an entire weekend, but I built a rack by repurposing some shelves I made, rack mounted four of the AHB2's you sent, soldered custom length Canare star quad cables (after seeing John Siau's YouTube video), and also added the Neutrik speakon connectors you recommended. I can't wait until I move to hear this in surround; it is going to be truly jaw dropping with the AIX tracks I have. For each speaker: one AHB2 is used to drive the midrange and tweeter and one AHB2 drives the woofer.
The custom Windows 10 PC uses JRiver and RME's ASIO hammerfall driver. It sends AES out from an RME HDSPe AES-32 sound card to the Xilica XD4080's AES input. The Xilica does FIR filtering for the WF/MR/TW filters and the DAC that feeds the AHB2 amps.
Of course the passive crossovers were removed from the speakers as I am striving for best at any price sound... and I think I'm there. The only thing that might be better is using software based FIR filtering and buying a bunch of DAC3's!
Since the original 2017 post, Ellery has made a number of upgrades to his already outstanding system:
His home theater now features 10 AHB2 power amplifiers.
In Ellery's words:
"I'm still very impressed with the amps. In fact, even three years later I still get goosebumps when listening to certain tracks."
All photos courtesy of Ellery Coffman
Front, Side and Ceiling Room Treatments
Rear Wall and Ceiling Room Treatments
Rear of Room Showing Earthworks Measurement Mic at Listening Position
Front Rack with Custom Water-Cooled PC (Upper Left Corner)
Custom Water-Cooled PC
Heat Sinks on Water-Cooled PC
Front Equipment Rack Featuring 6 AHB2 Power Amplifiers
Rear Equipment Rack Featuring 4 AHB2 Power Amplifiers
Rear of Main Equipment Rack
Front Equipment Rack (Before Adding Water-Cooled PC)
Secrets contributor Sumit Chawla recently caught up with Benchmark’s VP and Chief Designer, John Siau to get a little more in-depth on several subjects.
Q: "Benchmark is one of the few companies that publishes an extensive set of measurements, but you also balance that with subjective testing. Can you talk about the equipment, the listening room, and the process for subjective testing?"
Q: "Was there ever a time where you learned something from a subjective test that was not captured by measurements?"
Q: "You conducted some listening tests to determine whether distortion in the “First Watt” was audible. What test material did you use for this, and what did you find?"
Q: "The AHB2 amplifier incorporates THX Audio Achromatic Amplifier technology. When and how did the partnership with THX come about?"
Q: "Linear power supplies have been and remain quite popular in high-end devices. You favor switch-mode power supplies. When and why did you make this switch?"
... and more!
At Benchmark, listening is the final exam that determines if a design passes from engineering to production. When all of the measurements show that a product is working flawlessly, we spend time listening for issues that may not have shown up on the test station. If we hear something, we go back and figure out how to measure what we heard. We then add this test to our arsenal of measurements.
Benchmark's listening room is equipped with a variety of signal sources, amplifiers and loudspeakers, including the selection of nearfield monitors shown in the photo. It is also equipped with ABX switch boxes that can be used to switch sources while the music is playing.
Benchmark's lab is equipped with Audio Precision test stations that include the top-of-the-line APx555 and the older AP2722 and AP2522. We don't just use these test stations for R&D - every product must pass a full set of tests on one of our Audio Precision test stations before it ships from our factory in Syracuse, NY.
Paul Seydor of The Absolute Sound interviews John Siau, VP and chief designer at Benchmark Media Systems. The interview accompanies Paul's review of the LA4 in the December, 2020 issue of TAS.
"At Benchmark, listening is the final exam that determines if a design passes from engineering to production. But since listening tests are never perfect, it’s essential we develop measurements for each artifact we identify in a listening test. An APx555 test set has far more resolution than human hearing, but it has no intelligence. We have to tell it exactly what to measure and how to measure it. When we hear something we cannot measure, we are not doing the right measurements. If we just listen, redesign, then repeat, we may arrive at a solution that just masks the artifact with another less-objectionable artifact. But if we focus on eliminating every artifact that we can measure, we can quickly converge on a solution that approaches sonic transparency. If we can measure an artifact, we don't try to determine if it’s low enough to be inaudible, we simply try to eliminate it."
- John Siau
