ONYX 400F

Clock Source

There are three choices for selecting a clock source.

•INT (Internal): This is the default selection. The Onyx 400F operates using its own internal ex- tremely accurate, low-jitter clock. Select INT when you want the 400F to serve as the master clock in a system of digital devices.

•W.C. (Word Clock): The Onyx 400F operates using the clock from the device that is connected to the WORD CLOCK IN (18) jack on the 400F rear panel. Select W.C. when you want the 400F to be a slave in a system of digital devices.

•S/PDIF: The Onyx 400F syncs to the S/PDIF digital input (21) signal.

Note: If there is no clock present at the WORD CLOCK IN jack or no signal at the S/PDIF IN, you cannot select W.C. or S/PDIF and the clock source defaults to INT.

Another scenario is for overdubbing, where you are adding another track to some tracks already re- corded, which are routed from the DAW to the 400F via the DAW Outputs.

Headphones

This lets you select which outputs are routed to the headphone outputs. This selection applies to both headphone outputs 1 and 2 (and to the Control Room outputs).

•Mirror Outputs 1/2: Outputs 1 and 2 are routed to the left and right headphone outputs. The talent is hearing the same mix in the headphones as the engineer is in the Control Room outputs.

•Mirror Outputs 7/8: Outputs 7 and 8 are routed to the left and right headphone outputs. This allows you to create a separate mix for the talent, different from a control room mix you might have streaming out of outputs 1 and 2.

DSP Mixer

This turns the DSP Matrix Mixer on and off.

•Off: When the DSP Mixer is turned off, the 400F retains the last settings it had when the DSP Mixer was on. All the Output tabs are “greyed” out and the controls cannot be adjusted.

You might leave the DSP Mixer off if your computer has a lot of processing power and you are not con- cerned about the low-latency contributed by rout- ing the audio through the DAW software application and back to the Onyx 400F for monitoring. Another scenario is if you are just mixing and using the 400F as a 10x10 audio interface without using any extra routing (i.e., headphone monitoring).

•On: When the DSP Mixer is turned on, the Matrix Mixer is enabled and the five Output tabs are active and selectable. Each output tab controls the mix for a pair of outputs (i.e., 1/2, 3/4, etc.). These mixes are routed to the ten line outputs on the rear panel of the Onyx 400F. Each mix is comprised of the ten inputs (4 mic/line, 4 line, 2 S/PDIF) and two chan- nels returned from the DAW.

 

 

The inputs to the Onyx 400F are split off into two

 

 

directions after the A/D converters: one path goes

 

 

to the DSP Mixer and the physical outputs on the

 

 

400F, and the other path goes to the ASIO/Core Au-

 

 

dio inputs 1-10 of the DAW over the FireWire con-

 

 

nection. These are not affected by the DSP Mixer.

 

 

This lets you use the DSP Mixer for tracking a band

 

 

and creating zero-latency headphone mixes for

 

 

the talent using the line outputs routed through a

 

 

headphone distribution amplifier, while sending the

 

 

tracks to the DAW for recording.

 

 

 

 

 

 

 

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ONYX 400F

 

 

 

S/PDIF Format

There are two standard digital audio formats in common use: AES/EBU (Professional) and S/PDIF (Con- sumer). The audio data is the same for either format, just the non-audio data bits (subcode) are different.

In almost all cases, using the Consumer setting will work just fine. Occasionally, a S/PDIF device may want to see the Professional subcode and cause problems when using the Consumer setting. If you find that the digital audio is not being tranmitted or received cor- rectly, try using the Professional setting.

Note: If connecting a device equipped with an AES/EBU digital output to the S/PDIF input on the 400F using an AES/EBU-to-S/PDIF converter, set the S/PDIF format to professional.

Buffer Size

The buffer size is related to latency, which describes the amount of time it takes for audio to get in and out of your software application. The lower the buffer size, the lower the latency, and the faster audio can get into and out of the software application. However, a low buffer size requires more resources from your computer, so you need to find a happy balance between finding the lowest latency you can attain before the computer begins to have trouble routing and recording audio (e.g., drop- outs, pops, distorted audio).

Many DAW software applications have an ASIO control panel. In Tracktion 2, it is in the “Audio Devices” window in the “Settings” tab. Click the “Show ASIO control panel” button to open the ASIO control panel for the Onyx 400F . The buffer size in the ASIO control