Yamaha A-S801 class AB integrated amplifier
100 W + 100 W continuous 8 Ω 20 Hz to 20 kHz 0.019% THD
120 W + 120 W continuous 6 Ω 20 Hz to 20 kHz 0.038% THD
140 W 8 Ω 170 W 6 Ω 220 W 4 Ω 290 W 2 Ω IHF dynamic
Damping factor 240, frequency response 10 Hz to 100 kHz ±1.0 dB
DAC ESS Sabre ES9010K2M
Optical coaxial PCM 16 24 bit 32 44.1 48 88.2 96 176.4 192 kHz
USB PCM 16 24 32 bit 44.1 48 88.2 96 176.4 192 352.8 384 kHz DSD64 2.8224 MHz DSD128 5.6448 MHz
https://usa.yamaha.com/products/audio_visual/hifi_components/a-s801/index.html
https://data.yamaha.com/files/download/other_assets/1/1412681/web_VEX7500_A-S801_om_U_EnFr_A0.pdf
IHF dynamic power 1,000 Hz 20 msec = 20 cycles on, 480 msec off, 1% THD
https://faq.yamaha.com/usa/s/article/U0002483
Klipsch Heritage Forte IV
38 Hz to 20 kHz ±3 dB 8 Ω Nominal
99 dB SPL at 2.83 V at 1 m sensitivity = 5% efficiency
116 dB SPL maximum continuous, 17 dBW = 50 W
116 dB SPL at 50 W at 1 m = 105 dB SPL at 50 W at 11.6 ft
crossovers LF 650 Hz HF 5.2 kHz
crossover 650 Hz music energy 68% low pass 32% high pass
35.75” High by 16.63” Wide by 13” Deep 72 lbs
Baffle step frequency f3 = 380 / (16.63” / 12) = 274 Hz
https://www.klipsch.com/products/forte-iv-floorstanding-speaker
https://d2um2qdswy1tb0.cloudfront.net/spec-sheets/Forte-IV-Spec-Sheet-v01-1.pdf
Klipsch four fundamental principles https://www.klipsch.com/our-technology
Rod Elliott, Elliott Sound Products ESP, “Why Do Tweeters Blow?” https://sound-au.com/tweeters.htm
Rod Elliott, Elliott Sound Products ESP "Baffle Step Compensation" https://sound-au.com/bafflestep.htm
Speaker Sensitivity Volume & Pitch
Audiophile Heretic, July 14, 2026 Menu