# Other Topics

## What is phantom power?

Phantom power (also known as 48 V) is a DC voltage necessary to power condenser microphones such as the Neumann U87 or AKG 414. If youʼre connecting a condenser mic to ONE, be sure to select Ext 48V Mic in the Maestro Control Input menu. Through a bit of electronic trickery, phantom power is supplied to the mic via the same cable used to transmit the audio signal from the mic.

There are a few precautions to take when using phantom power.

- Donʼt connect a ribbon mic when phantom power is on.

- Mute headphones or speakers before toggling 48V on or off.

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How do I set my softwareʼs I/O buffer?

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. A lower buffer setting results in lower latency but less available processing power. If the application canʼt 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 computerʼs full processor power when latency isnʼt an issue.

With the processing power of todayʼs Macs, you may find that adjustment of the buffer isnʼt 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, donʼt hesitate to experiment with the buffer setting.

Please consult the section “Configuring Core Audio Applications” to determine where the I/O buffer setting is found in your audio application.

## What sample rate should I record at?

Symphony I/O operates at the complete range of standard sample rates from 44.1kHz to 192kHz. So, whatʼs the best sample rate to record your project at? Itʼs a good idea to avoid unnecessary sample rate conversion stages, so the answer is determined by the sample rate of media on which you plan to distribute your recording.

- If the final distribution media is CD, record at 44.1kHz.

- If the media is video or TV, most often 48 kHz is the best choice.

- If youʼre part of a larger production chain, and arenʼt sure, ask whomever is responsible for assembling the final product - theyʼll undoubtedly appreciate the forethought.

## Can I record my session on the startup hard drive?

Itʼs an accepted “best practice” of most audio software providers that audio files should be recorded on a hard drive other than the Macʼs Startup drive (i.e. the drive on which the operating system is installed). You can probably get away with recording a few tracks to your computerʼs Startup disk, but for the best performance of your Symphony I/O recording system, record onto a separate ATA/IDE, SATA, or FireWire drive whose spindle speed is at least 7200 RPM.

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