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!
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!
All photos courtesy of Ellery Coffman
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
The Benchmark AHB2 power amplifier and HPA4 headphone amplifier both feature feed-forward error correction. This correction system is an important subset of the patented THX-AAA™ (Achromatic Audio Amplifier) technology. It is one of the systems that keeps these Benchmark amplifiers virtually distortion free when driving heavy loads. It is also the reason that these amplifiers can support 500 kHz bandwidths without risk of instability when driving reactive loads.
This paper explains the differences between feedback and feed-forward systems. As you read this paper, you will discover that you already understand the benefits of feed-forward correction because you use it instinctively to improve a feedback system commonly found in your automobile. If feed-forward correction can improve your driving experience, it may also improve your listening experience!
- John Siau