|The I/O Buffer setting found in most audio software is one of the most crucial, but often ignored, settings in a Mac-based recording system. When choosing a buffer setting, a compromise between the latency through the application and the amount of computer processor power accessible to the application must be made.Latency– the slight delay between the moment you play a note and hear it in your headphones after conversion and processing.
A lower buffer setting results in lower latency but less available processing power. If the application can’t access enough processor power, processor overruns may occur, resulting in audible clicks and pops or error messages that interrupt playback and recording. A higher buffer setting, on the other hand, results in greater amount of accessible processor power (i.e. less chance of overruns) but increases the latency. Determining the best setting requires some trial-and-error in order to find the best compromise.
Keep in mind that as tracks and plug-ins are added to a software session, processor requirements increase. Thus, the buffer setting that works during the early stages of a session might result in processor overruns during later stages. The best strategy is to set the buffer to a lower setting during recording and accept certain limitations on plug-in usage, and then raise the buffer during mixing to utilize the computer’s full processor power when latency isn’t an issue. With the processing power of today’s Macs, you may find that adjustment of the buffer isn’t necessary, and you can leave it at a setting for low latency and still access a sufficient amount of processing power when adding tracks and plug-ins. If you do encounter clicks, pops or software errors, don’t hesitate to experiment with the buffer setting. Please consult the section on Working with GarageBand, Logic and Mainstage to determine how to se the I/O buffer setting is found in your audio application.
Make sure that there are no other FireWire devices connected to the Mac. The Ensemble must be the only FireWire device connected to the Mac when updating the firmware.
When Ensemble is connected to AC power, the power switch illuminates dimly to indicate that the unit is in Standby mode. Press the power switch to power up Ensemble.
Open Maestro, on the Output tab set Meter Display to Output and verify that a signal is displayed on the meters. If there is no signal on the meters, check the routing from the audio application. If signal is displayed on the meters but not present at analog outputs 1-2, check that the MAIN output level is turned up either in Maestro or using the front panel OUTPUT encoder.
Verify that the required version of OS X is installed. Verify that Ensemble’s STATUS LED is solid blue. Check to see if the Ensemble shows up in the Apple System Profiler. You can check this by going to the Apple menu, choosing About This Mac and clicking on “More Info…”. Click on FireWire under the Contents column on the left to make sure the Ensemble is recognized by the Mac.
To operate Ensemble at a sample rate of 176.4 or 192 kHz, it’s necessary to set I/O Allocation to either 10×10 or 8×8. The I/O Allocation setting is found on the Settings tab of the Maestro Control window. As ADAT optical I/O is not supported at these sample rates, their associated Firewire paths are disabled to conserve bandwidth. After changing I/O Allocation, it’s strongly recommended to restart the computer and power cycle the Ensemble.
The Status LED is flashing blue indicating that the Ensemble is not locked to the selected clock source. Go to the Settings tab of the Maestro Control page and verify that Clock Source Select is set properly. If it is set correctly and the Status LED is still flashing blue, then change Clock Source Select to any other setting and wait 15 seconds. Now change Clock Source Select back to your desired setting. The Status LED should now be solid blue.