SP395 SoundPro Audio Integrator
Form7492
Operation Manual
93
USB Preamp Operation
The SP395 may be used as a calibrated USB microphone preamp. Since the audio signal is split
before being routed to the DSP for processing, you can use the Audio Integrator functions and
the USB preamp at the same time. For example, you can use the SP395 as a sound card for a PC-
based analysis program, like SmaartLive, while you record the A-weighted sound level, using the
Sound Study Graph.
The USB Audio Interface permits digital audio between a computer and the SP395.
To use the SP395 as a USB preamp:
1.
Connect microphone(s)
Connect one or two microphones to the SP395’s inputs.
2.
Phantom Power
Enable 48V phantom power, if required. (Top Tool Bar)
3.
Set Input Gain
Adjust the input gain settings to an appropriate level. You can use the
Auto-gain setting function, but, realize that when the gain changes, you may hear an
audible click.
4.
Set Gain Trim.
Use the Gain Trim controls to adjust the level to the USB port in 0.01 dB
steps. Select Utilities in main menu and select Tools in the submenu to permit USB
Preamp Control on the SP395.
5.
Connect USB cable
Plug a standard USB cable from the host PC to the Integrator. Since
the PC is the host, and the SP395 is the peripheral, the square end of the cable goes into
the SP395 and the flat end goes into the PC.
6.
Set the Sample Rate.
The SP395 USB output runs only at 48k. Set your computer’s
sample rate to 48k (48000).
7.
Computer Setup
No special software driver is required, as the SP395 USB section
appears as a standard USB audio codec. You may, however, have to adjust the computer’s
sample rate to 48 kHz, since the SP395 output runs only at 48,000 samples/second.
Windows XP note: Most operating systems allow setting the SP395 to either 44.1 or 48
kHz sample rate. Windows XP, however, allows using only the 48 kHz sample rate
setting. Set both the SP395 and the Windows XP driver to 48 kHz.
Any audio that enters the SP395’s inputs is routed to the computer over the USB audio link. You
can still use the SP395 normally, running audio analysis or tests, while the digital audio is being
routed to the computer. You can even change functions without losing the USB connection to the
PC.
