User`s guide

User's Guide Fireface 400 © RME

9.3 Known Problems

If a computer does not provide sufficient CPU-power and/or sufficient FireWire transfer rates,

then drop outs, crackling and noise will appear. Such effects can be avoided by using a higher

buffer setting/latency in the Settings dialog of the Fireface 400. Furthermore PlugIns should be

deactivated temporarily to make sure they do not cause these problems.

More information can be found in chapter 30.3.

Another common source of trouble is incorrect synchronization. ASIO does not support asyn-

chronous operation, which means that the input and output signals not only have to use the

same sample frequency, but also have to be in sync. All devices connected to the Fireface 400

must be properly configured for Full Duplex operation. As long as SyncCheck (in the Settings

dialog) only displays Lock instead of Sync, the devices have not been set up properly!

The same applies when using more than one Fireface. They all have to be in sync. Else a peri-

odically repeated noise will be heard.

RME supports ASIO Direct Monitoring (ADM). Please note that some programs do not fully

support ADM. The most often reported problem is the wrong behaviour of panorama in a stereo

channel.

In case of a drift between audio and MIDI, or in case of a fixed deviation (MIDI notes placed

close before or behind the correct position), the settings in Cubase/Nuendo have to be

changed. At the time of print the option 'Use System Timestamp' should be activated. The Fire-

face supports both MME MIDI and DirectMusic MIDI. It depends on the used application which

one will work better.

10. Using more than one Fireface

The current driver supports up to three Fireface 400 and 800. All units have to be in sync, i.e.

have to receive valid sync information (either via word clock or by using AutoSync and feeding

synchronized signals).

• If one of the Firefaces is set to clock mode Master, all others have to be set to clock mode

AutoSync, and have to be synced from the master, for example by feeding word clock. The

clock modes of all units have to be set up correctly in the Fireface Settings dialog.

• If all units are fed with a synchronous clock, i.e. all units show Sync in their Settings dialog,

all channels can be used at once. This is especially easy to handle under ASIO, as the ASIO

driver presents all units as one.

When using more than one Fireface 400 it might be necessary to deactivate some channels.

Using more than one Fireface 400 together with a FireWire hard drive (hub functionality) can

cause audio problems. More information about numbers of channels and bus load can be found

in chapter 30.4.

The driver takes care of the numbering of all Firefaces, so that it doesn't change. The unit with

the lowest serial number is always 'Fireface (1)'. Please note:

• If the Fireface (1) is switched off, Fireface (2) logically turns to the first and only Fireface. If

Fireface (1) is switched on later, the numbering changes and the unit becomes Fireface (2)

immediately.