AdamFrandsen
Active Member
Hi Amir and ASR community,
Thank you for the outstanding work and dedication to providing detailed and objective audio measurements. I’ve learned a great deal from your reviews and deeply appreciate the scientific rigor you bring to the audiophile world.
I’d like to suggest adding burst power testing and slew rate measurements to ASR’s testing methodology for amplifiers. These tests can complement existing metrics like THD, IMD, and SNR by providing additional insights into an amplifier’s real-world performance, particularly its ability to handle transients and dynamic demands.
Why Burst Power and Slew Rate Are Important
1. Real-World Music Playback:
• Music is dynamic, with sudden transients (e.g., drum hits, orchestral crescendos) that place brief but significant demands on an amplifier’s power supply and output stages.
• Continuous power tests don’t fully capture how an amplifier performs during these short bursts, which are critical for perceived dynamics, impact, and energy.
2. Transient Response and Speed:
• Slew rate reflects an amplifier’s ability to handle rapid changes in signal amplitude, which affects high-frequency content and perceived clarity.
• While bandwidth measurements may imply sufficient slew rate, explicitly testing it can reveal subtle limitations that affect performance with highly dynamic or complex signals.
3. Dynamic Headroom and Power Delivery:
• Burst power tests can reveal an amplifier’s ability to deliver extra power for short durations without clipping or voltage sag, which is especially relevant for amplifiers with limited continuous power ratings.
How to Perform These Tests Using the APx555
1. Burst Power Testing:
• Test Signal: Generate short-duration sine wave bursts (e.g., 10ms on, 90ms off) at different frequencies (e.g., 40 Hz, 1 kHz).
• Measurement Goals:
• Peak burst power output before clipping.
• Distortion (THD+N) during the burst.
• Voltage sag and recovery during the burst.
• Benefits: Highlights the amplifier’s dynamic headroom and power supply stability under real-world transient demands.
2. Slew Rate Testing:
• Test Signal: Use a square wave or fast-rising sine wave. Ensure the rise time challenges the amplifier’s speed.
• Measurement Goals:
• Slew rate = ΔVoltage / ΔTime (V/μs).
• Evaluate consistency across loads (e.g., 4 ohms, 8 ohms).
• Benefits: Provides direct insight into how quickly the amplifier can respond to transient changes, which affects perceived detail and resolution.
Addressing Potential Concerns
1. Relevance to Audible Performance:
• While amplifiers may meet basic thresholds for transient handling, measuring burst power and slew rate explicitly can help identify subtle performance differences, particularly in demanding systems or high-dynamic-range playback scenarios.
2. Redundancy with Existing Tests:
• Bandwidth tests suggest adequate slew rate, but they don’t measure the amplifier’s actual response speed. Similarly, continuous power tests don’t reveal how an amplifier handles dynamic peaks or recovers from transient demands.
• These tests fill gaps left by existing methods, providing a more comprehensive view of real-world behavior.
3. Complexity and Standardization:
• The APx555 is well-suited for both burst power and slew rate testing, making implementation straightforward.
• Consistent testing protocols can be developed, such as fixed burst durations (e.g., 10ms) and specific rise times for slew rate evaluation, ensuring repeatability and comparability across reviews.
Why It Adds Value to ASR
Incorporating burst power and slew rate tests can:
• Provide insights into an amplifier’s transient handling that align with real-world music playback.
• Help differentiate amplifiers beyond traditional metrics, especially in systems that emphasize dynamic range and clarity.
• Maintain ASR’s reputation for thorough, science-driven evaluations by addressing both static and dynamic performance aspects.
I hope this suggestion sparks discussion and exploration. Thank you for considering this addition, and I look forward to hearing the community’s thoughts!
Best regards,
Adam
Thank you for the outstanding work and dedication to providing detailed and objective audio measurements. I’ve learned a great deal from your reviews and deeply appreciate the scientific rigor you bring to the audiophile world.
I’d like to suggest adding burst power testing and slew rate measurements to ASR’s testing methodology for amplifiers. These tests can complement existing metrics like THD, IMD, and SNR by providing additional insights into an amplifier’s real-world performance, particularly its ability to handle transients and dynamic demands.
Why Burst Power and Slew Rate Are Important
1. Real-World Music Playback:
• Music is dynamic, with sudden transients (e.g., drum hits, orchestral crescendos) that place brief but significant demands on an amplifier’s power supply and output stages.
• Continuous power tests don’t fully capture how an amplifier performs during these short bursts, which are critical for perceived dynamics, impact, and energy.
2. Transient Response and Speed:
• Slew rate reflects an amplifier’s ability to handle rapid changes in signal amplitude, which affects high-frequency content and perceived clarity.
• While bandwidth measurements may imply sufficient slew rate, explicitly testing it can reveal subtle limitations that affect performance with highly dynamic or complex signals.
3. Dynamic Headroom and Power Delivery:
• Burst power tests can reveal an amplifier’s ability to deliver extra power for short durations without clipping or voltage sag, which is especially relevant for amplifiers with limited continuous power ratings.
How to Perform These Tests Using the APx555
1. Burst Power Testing:
• Test Signal: Generate short-duration sine wave bursts (e.g., 10ms on, 90ms off) at different frequencies (e.g., 40 Hz, 1 kHz).
• Measurement Goals:
• Peak burst power output before clipping.
• Distortion (THD+N) during the burst.
• Voltage sag and recovery during the burst.
• Benefits: Highlights the amplifier’s dynamic headroom and power supply stability under real-world transient demands.
2. Slew Rate Testing:
• Test Signal: Use a square wave or fast-rising sine wave. Ensure the rise time challenges the amplifier’s speed.
• Measurement Goals:
• Slew rate = ΔVoltage / ΔTime (V/μs).
• Evaluate consistency across loads (e.g., 4 ohms, 8 ohms).
• Benefits: Provides direct insight into how quickly the amplifier can respond to transient changes, which affects perceived detail and resolution.
Addressing Potential Concerns
1. Relevance to Audible Performance:
• While amplifiers may meet basic thresholds for transient handling, measuring burst power and slew rate explicitly can help identify subtle performance differences, particularly in demanding systems or high-dynamic-range playback scenarios.
2. Redundancy with Existing Tests:
• Bandwidth tests suggest adequate slew rate, but they don’t measure the amplifier’s actual response speed. Similarly, continuous power tests don’t reveal how an amplifier handles dynamic peaks or recovers from transient demands.
• These tests fill gaps left by existing methods, providing a more comprehensive view of real-world behavior.
3. Complexity and Standardization:
• The APx555 is well-suited for both burst power and slew rate testing, making implementation straightforward.
• Consistent testing protocols can be developed, such as fixed burst durations (e.g., 10ms) and specific rise times for slew rate evaluation, ensuring repeatability and comparability across reviews.
Why It Adds Value to ASR
Incorporating burst power and slew rate tests can:
• Provide insights into an amplifier’s transient handling that align with real-world music playback.
• Help differentiate amplifiers beyond traditional metrics, especially in systems that emphasize dynamic range and clarity.
• Maintain ASR’s reputation for thorough, science-driven evaluations by addressing both static and dynamic performance aspects.
I hope this suggestion sparks discussion and exploration. Thank you for considering this addition, and I look forward to hearing the community’s thoughts!
Best regards,
Adam