The FFT … an Audio Microscope.

An FFT analyzer is like an audio microscope. It allows us to easily measure the frequency and amplitude of tones that are below the level of the noise. Traditional audio meters fail when the signal is lower than the noise level, but with an FFT, we can accurately measure tones that are 30 to 40 dB below the level of the noise.

In many ways, our ears behave like an FFT audio measurement system. Our ears can detect the frequency and amplitude of tones that are as much as 30 dB below the ambient noise. This means that our ears are 30 dB better than traditional audio meters! This is why we can carry on a conversation in a noisy room, and this is why we can hear individual instruments within an orchestra. This is also why small defects need to be detected and corrected when designing top-quality audio gear.

John Siau, Benchmark’s lead Engineer, will explain the “magic” of the FFT analyzer without the use of advanced mathematics. He will show an FFT analyzer in action, and he will measure a complete Benchmark chain to determine if it produces audible noise or distortion. Learn how to read an FFT plot and learn what to look for when selecting audio components.

Products Discussed in this Video

The Benchmark AHB2 Power Amplifier

• Radically Different Topology
• Hi-Frequency Fully-Regulated Switched-Mode Power Supply
• Linear Class-AB output Stage with Class-H Tracking Rails
• Much more Efficient than a Traditional Class-AB Amplifier
• Feed-Forward Error Correction
• Correction Amplifier is Passively Summed with the Main Amplifier
• No Magnetic Interference
• No Relays in Output Stage
• Protection Circuits are not in Series with Output Path
• Low Gain Design
• Tweeter Protection
• 0.1 Hz to 250 kHz Bandwidth
• Stable into Inductive and Capacitive Loads
• Stable into Very Low Impedances
• 135 dB SNR
• THD is Better Than -110 dB at Full Output Power

The Benchmark HPA4 Headphone Amplifier

• THX-888 Headphone Amplifier featuring Feed-Forward Error Correction
• Entire Signal Path is Relay Controlled
• 256-Step Relay-Controlled Volume
• Lowest Noise, Lowest Distortion Preamplifier Available
• International Power Supply
• High Power Headphone Output
• Independent Line-Level Output
• Certified for Pro or Hi-Fi Applications
• Supports full Studio-Level Balanced Inputs and Outputs
• 0.1 Hz to 500 kHz Bandwidth

The Benchmark LA4