R. R. Cordell 10/18/03 Athena

R. R. Cordell 10/18/03 Athena

R. R. Cordell 10/18/03 Athena SYSTEM Way self-powered TMWWWW 4 37 X 7 X 16 mini tower 4 built-in 4-channel amplifier per box 4 time-aligned, transient accurate 4 sloped baffle (11 degrees)  Equalized Quasi Sealed System ( EQSS  ) 4 adjustable electronic baffle step compensation

Athena DRIVERS 4 Vifa D27TG silk dome tweeter 4 Vifa TC08WD inch midrange 4 four McIntosh 5.25-inch woofers –fs:55 Hz –Vas:15.5 L –Qts:0.35 –Xmax:2.5 mm

Athena ACTIVE CROSSOVER Hz and 4000 Hz first order electrical Hz constant-voltage half-way cross 4 twin-tee passive 9 kHz midrange notch  EQSS  biquadratic LF equalizer 4 electronic Baffle Step Compensation 4 adjustable BSC (amount and frequency) 4 signal sense for auto turn-on

Athena AMPLIFIERS 4 four 125 Watt power amplifiers per box 4 MOSFET output with JFET input 4 boosted driver supply for max headroom 4 flying catch diodes for non-saturating clip 4 symmetrical, stick-free clipping 4 high current design stable to < 2 ohms 4 clip indicator

Athena AMPLIFIERS (cont.) 4 folded complementary push-pull driver 4 fast, low-voltage output stage drivers 4 servo-controlled output offset 4 no capacitors or inductors in the signal path 4 small physical size 4 70 V/us slew rate 4 < 0.03% THD to 20 full power

Athena AMPLIFIERS (cont.) Flying Catch Diodes 4 limit max gate-source voltage 4 prevent driver saturation in clipping 4 provide adaptive symmetrical clipping 4 prevent saturation of folded EF drivers 4 prevent reverse base breakdown in EF drivers 4 prevent driver damage from output device short

Athena EQSS  System 4 objective - big sound from small box 4 9 liters per 5.25-inch woofer 4 53-Hz woofer f0 4 box tuned to 37 Hz Hz, second order, Q=0.7

Athena EQSS  THEORY 4 Quasi Sealed System: –ported, but box tuned very low –resulting response approximates sealed system 4 Equalize as if a sealed system –use parameters of sealed system it approximates 4 port increases LF excursion-limited SPL 4 transient response like that of sealed system 4 applicable to subwoofers as well

Athena POWER MANAGEMENT 4 auto turn-on at signal detect 4 5 minute on time in absence of signal 4 inrush current control 4 speaker relay delay control