Setting Proper System Gain for Optimized Audio Performance
Are You Driving Your Audio System in the "Wrong Gear"?
A race car produces peak power when the transmission is in the proper gear. Likewise, an audio system produces peak performance when each component is running at an optimum signal level. We can put a race car on a dynamometer and measure the power that is delivered to the wheels. We can also measure the loss of power that comes from driving in the wrong gear.
Likewise, we can hook an audio system up to a test station and measure the power and noise that is delivered to our speakers. We can also measure the loss of performance that comes from operating the audio system in the "wrong gear".
Volume controls and gain switches are the "gearboxes" in an audio system. Learn how to "drive in the right gear".
John Siau will take us into Benchmark's Engineering Lab for a performance driving lesson. He will show end-to-end performance measurements of a high-performance Benchmark audio system. He will even "shift it into the wrong gears" so that you can see the resulting loss of performance.
Leave a comment
Comments will be approved before showing up.
Also in Videos
John Siau Interview at CAF2025 - Carlo Lo Raso, SECRETS of Home Theater and High Fidelity
"I got a chance to sit down with John Siau, VP of Benchmark Media Systems, while at Capital Audiofest 2025. John talks to me about what makes the current crop of Benchmark DACs a little extra special." - Carlo Lo Raso
... and much more!
How Loud is the Distortion from Your Power Amplifier?
In this video, John Siau extracts the data from the published test results of 7 top-rated audiophile power amplifiers. Hidden within the THD+N vs. Power graphs are the answers to two key questions:
- How loud is the noise produced by my power amplifier?
- How loud is the distortion produced by my power amplifier?
Your Amplifier THD+N may be Louder than a Washing Machine!
Don't take our word for it! The evidence is captured in the hundreds of test reports compiled by Stereophile Magazine. Unfortunately, we cannot see this information when looking at traditional THD+N graphs. We need to extract the raw data from the Stereophile graphs and do a bit of math.
John Siau shows that the distortion produced by some of these top-rated amplifiers is louder than the noise that would be produced by having a washing machine in the middle of your listening room!
You wouldn't put a major appliance in the middle of your listening space, so you may want to take a careful look at your power amplifier.
Traditional THD+N Measurement Units Hide the Truth!
THD+N is usually plotted in terms of percent. This is a problem because percent is not a measure of loudness, nor is it a logarithmic unit. If we plot THD+N in terms of loudness (dB SPL) at the listening position, we can easily visualize the noise floor of the amplifier, and we can read the loudness of the THD directly from the graph.
Amplifiers are the Weak Link in the Electronic Chain
In most systems, the power amplifier will generate more THD+N than all of the other electronic components combined. It is time to take a fresh look at amplifier perfomance measurements. The evidence is hiding in Stereophile's test reports!
Feed-Forward Correction Explained!
Feed-Forward Error Correction
Don't look back, the future is here!
Benchmark's AHB2 power amplifier has a unique feedforward error correction system that cancels distortion before it reaches the speaker terminals. In contrast, global feedback systems attempt to correct the distortion after it reaches the speaker terminals.
Feed-forward correction is fast, precise, and inherently stable.
Benchmark's AHB2 blends feedback with feed-forward correction to leverage the best characteristics of each.
Listen to Gene and John as they discuss this revolutionary technology.
- How does the feed-forward system know what correction to send?
- Does it predict the future?
- What makes feedback unstable when driving capacitive loads?
- Why is feed-forward stable when driving capacitive loads?
Take a few minutes to learn how feed-forward error correction works:
- Watch as John provides an easy-to-understand analogy for feed-forward error correction.
- Join the discussion.
- We reserve the right to limit negative feedback.