Henry Engineering Studiodrive - Manual (Page 3)

PAGE 3
The following line level inputs should be wired as follows: TIP = HI, RING = LO, SLEEVE = GND.
For unbalanced sources connect the RING and SLEEVE together.
LINE 2 LEFT Line input #2, left channel.
Input sensitivity set by JP1.
LINE 2 RIGHT Line input #2, right channel. Input sensitivity set by JP2.
P.C. LEFT Input for PC soundcard playback, left channel. Input sensitivity set by JP3.
P.C. RIGHT Input for PC soundcard playback, right channel. Input sensitivity set by JP4.
AIR MON LEFT Input for Air monitor, left channel Input sensitivity set by JP8.
AIR MON RIGHT Input for Air monitor, right channel Input sensitivity set by JP9.
TEL
Connect to POTS line to record caller audio. TIP = RED, RING = GREEN, SLEEVE N/C
Note: the telecoupler bridges the telephone line. A standard telephone should also be connected
to the line to seize (terminate) the line while recordings are made (for recording caller audio only).
Note: A telephone hybrid must be used if both the caller and host are to be recorded or broadcast,
e.g., for a “talk show”. In this case, the hybrid’s caller audio output may be fed to the TEL input.
MONI L+R
Unbalanced output to studio monitor system. TIP = LEFT, RING = RIGHT, SLEEVE = GND.
MIX MINUS
Unbalanced output to feed “send” input of hybrid, if used. TIP = HI, SLEEVE = GND.
The following balanced outputs should be wired as follows: TIP = HI, RING = LO, SLEEVE = GROUND.
For unbalanced loads, connect to TIP and SLEEVE ONLY. DO NOT SHORT RING TO GROUND!
PGM LEFT
Main Program output, left channel, on-air feed. (0 VU = +4 dBu)
PGM RIGHT Main Program output, right channel, on-air feed. “
REC LEFT
Record bus output, left channel, to input of PC soundcard. (Output level adjustable.)
REC RIGHT Record bus output, right channel, to input of PC soundcard. “
TALLY/COUGH Logic circuits for mic control and On The Air warning light control:
TALLY: Provides +12 volts between TIP and SLEEVE when Mic is on. Connect to Henry
` Engineering Superelay DC control inputs to activate warning lights when Mic is on.
COUGH: Connect an external N.C. switch or pushbutton between the RING and SLEEVE to
control Mic. Opening the circuit turn Mic off; closing circuit turns mic on.
Note: JP2 in Audio Interface unit must be ON to enable remote Mic on/off control.
2.3 RECORD OUTPUT LEVEL CALIBRATION
Plug the flat cable from the Audio Interface unit into the header on the StudioDrive chassis. Be sure that the RED
STRIPE on the cable is at the right end of the header, as viewed from the rear of the StudioDrive chassis.
After all audio connections have been made the system can be powered up. Calibration consists of adjusting the
StudioDrive RECORD OUTPUT level to match in input sensitivity of the PC soundcard.
Average vs. peak levels
All PC recording/editing software has some type of on-screen audio level meter. Some meters read average levels,
while others read peak levels. The purpose of the meter should be to show average perceived level, so that all
recordings will play back at a consistent perceived level. Unfortunately, some on-screen level meters actually read
absolute peak levels. While this is useful to prevent system overloads, peak-reading meters are of little use in
determining average perceived level. Check the manual for the software being used to determine what the on-
screen meter indicates.
The best way to calibrate a PC soundcard recording system is to determine the maximum operating level (“clipping
point”) for the system, then establish 0-VU at 15 to 20 db below the clipping point. This will ensure adequate
headroom above 0-V U for distortion-free audio peaks. Note: StudioDrive’s clipping point is 20 dB above 0-VU.
To calibrate record levels, feed a test tone (about 400 Hz) into any StudioDrive line input. Carefully set the level so
that the amber “0-VU” LED is lit. (This produces exactly +4 dBu at the Program outputs.)
Now put the soundcard into the RECORD mode. Adjust StudioDrive’s REC CAL trimmers to produce the
appropriate level into the soundcard. The REC CAL trimmers are at the back of the StudioDrive PC board.