Monday, February 21, 2011

Very thorough analysis of audio system issues

For example, they analyze the effects of different interconnect impedances and determine the optimal source impedance is in the neighborhood of 50-100 ohms.  Actually 90 ohms yields the lowest peaking (most interconnect systems peak at some ultrasonic frequency; it's LCR with very low R) whereas 60 ohms yields the most extended response (from the low pass network created).  Current best practice in audio is balanced interconnection, 50-100 ohms source impedance into 100k ohm load, 200khz bandwidth per component (in a multicomponent system, all the roll offs add up, so you need margin to maintain 20khz, they assume 5 analog components in series is possible), and 5v/us minimum slew rate (less than that, and you get slew rate limiting into the now pro standard +28dBu (aka 20 volts RMS) at 30kHz.  (Then they laugh at adage "a system is only as good as it's weakest link", of course a real system is always *worse* than it's weakest link.)

No comments:

Post a Comment