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)
Myth - "Damping Factor Isn't Much of a Factor"
Myth - "A Damping Factor of 10 is High Enough"
Myth - "All Amplifiers Have a High-Enough Damping Factor"
These myths seem to trace back to a well-know paper written by Dick Pierce. His analysis shows that a damping factor of 10 is virtually indistinguishable from a damping factor of 10,000 when it comes to damping the motion of a loudspeaker cone. This analysis has been examined and repeated in many more recent articles, such as a well-written post on Audiofrog.com by Andy Wehmeyer. Articles such as these are often cited as evidence that amplifier damping factor doesn't matter. The mathematical analyses are correct, but the conclusions are incomplete and misleading!
How fast things can change!
It is March 23, 2020 and we are currently battling the worldwide COVID-19 pandemic.
This application note will be a departure from normal. I will make a few observations about the current situation and then look at the nuts and bolts of how we reconstructed our operations in less than 48 hours. Benchmark is 100% operational, but nothing looks the same as it did last week.
- John Siau
As an engineer I like to use "rules of thumb" to make quick estimates that help to explain the physical world around me.
These rules of thumb are easy-to-remember approximations that eliminate the need for complicated and needlessly precise calculations.
If you feel discombobulated by the complexities of high school physics, there is hope! I encourage you to step back and take a fresh approach.
If you learn a few simple rules of thumb, you can unravel mysteries of the physical world, amaze your friends, and yourself.
In this paper I will present 15 simple rules that I find useful when working with music and audio.
- John Siau
