By John Siau
Do Specifications Lie? Do Our Ears Lie? Where does the Truth Lie?
Recording Engineers and Audiophiles often distrust audio measurements and specifications. It is not uncommon to hear claims that a product measures poorly but sounds good. Occasionally we also hear claims that a product measures well but sounds bad.
This whitepaper documents significant differences between three headphone amplifiers that have nearly identical published specifications.
All three products have a high-quality headphone output with very low output impedance, high drive capability, low distortion, and a flat frequency response. The published specifications strongly suggest that it should be impossible to hear any difference between these products. Nevertheless, in our informal listening tests, we had the distinct impression that there were significant sonic differences between these products when listening to music.
We replicated the manufacturers' tests and found that the published specifications were accurate and correct. All three manufacturers followed standard measurement procedures and provided accurate specifications.
This paper shows some additional measurements which expose significant differences that do not appear in traditional published specifications:
"Greater love hath no man than this, that a man lay down his life for his friends." - John 15:13
On the evening of July 17, 2022, my oldest son David Paul Siau gave the ultimate sacrifice of love when he knowingly gave his life to save those he loved. He took three shots from a 12 gauge shotgun so that his wife, children and sister could be spared.
David is survived by his wife Christy Siau and their two oldest children, ages 6 and 3. His 18-month old daughter McKenzie was killed within moments of David. I have no doubt that David and McKenzie entered into God’s glory hand in hand.
My daughter-in-law Christy Siau was shot and nearly killed in the incident. We are grateful that she is now out of the hospital making a full recovery.
In the end, my daughter Christina Siau fought the attacker with a knife and prevailed. She sustained many knife injuries and it is a miracle that she lived. She is now out of the hospital and making a full recovery.
We ask your prayers for the healing of physical and emotional scars. We have been overwhelmed by the love people have shown to our family during this difficult time.
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.