Studio
Home Digital Audio Hooking Up Clock Sync

Currently, there are five pieces of equipment in the studio that need to be audio synced by master clock.

  • 2 x Yamaha 02R
  • Yamaha 01V96
  • Behringer ADA-8000
  • RME Hammerfall 9652

For my reasoning and research behind introducing clock sync into the studio, see this article.

rosendahl-nanosyncs-hd

My external master clock device is a Rosendahl Nanosyncs Audio/Video Master Sync/Word Clock, which I only use for its audio word clock. Perhaps at some point, I'll also use it for its video sync capabilities, but I don't think I even have any video equipment that can take a video clock sync signal anyway.

Aside from the actual devices, connecting up necessitates having the right types of cables between the devices. Since audio clock sync is usually connected with what is called a BNC connector, which is a coaxial cable of either 50 ohms or 75 ohms impedance. The connector itself is a bayonet-type lug on each end, which is what the "B" in the acronym comes form (the full name is Bayonet Neill-Concelman). The male end is typically on the device being connected. The different impedances for the cable each serve a different purpose. The 50 ohm cable is used for composite video for professional video devices and in conjunction with an adapter with consumer devices with RCA connectors.

The 75 ohm impedance cable serves a different purpose due to its use in higher frequences in the 2 GHz range (instead of the 1 GHz range for the 50 ohm cable). It is this type of cable that is needed for clock sync in digital recording equipment. Often a cable has the specs printed on the cable sheath, so take care to look and ensure that your cable is indeed the 75 ohm type. Although a 50 ohm could be used for a synchronization application, but there may be phase problems introduced, which is not what we want to happen during sync because it will degrade the sync signal and you would be left with poorly synced or even unsynchronized devices, defeating the purpose of building a synced system in the first place. So ensure you have the right type of cable: BNC at 75 ohm.

Connecting Up

The Nanosyncs is the central figure in the master clock setup. Connecting all the devices results in a star network or star topology, where a central hub (the master clock unit) connects to nodes (the other devices individually connected by a BNC cable).

Star topology
With this star topology, no secondary devices can hang off a node (an end device) in the star. The reason is that the nodes have to be configured as slaves to the master clock. When a device is set to being a slave, however, it cannot generate a clock signal that a secondary device connected to it could be the slave. In other words, once set as a slave, it cannot be a master. Seems almost biblical. However, devices can be daisy chained using a BNC T-connector at the node device (which splits the clock signal), then connecting another BNC cable from the T-connector to the next device. This can potentially continue indefinitely, but many resources don't recommend the practice, likely due to signal degradation from long chains.

Connecting to all the devices in the network is easy. I simply attached a BNC cable from the back of the Nanosyncs on one of the word clock connector ports to one of the devices. Look for a Word Clock in connector port on the back of the device. It's pretty unique from all the other connectors on the devices and it should be labled "IN".

Set the node device to synchronize to an external word clock. If your master clock is on and the node device is set to sync to word clock (or external word clock), it should immediately synchronize to the specific clock rate. If not, there may be a problem with the cable, output port on the master clock device, input port of the node device, or the guts of the node device; you'll have to troubleshoot if that's the case, starting with looking into the owner's manual of the device or finding some resources on the web.

You may want to be able to switch between clock rates depending on your workflow. I typically switch between 48 kHz and 44.1 kHz, the former when I'm recording and mixing and the latter when I've finished mixing and doing the final mastering step of assembling the CD project. Prior to getting the Nanosyncs, I would switch clock rates on the main 02R, but now the clock rate is switch on the Nanosyncs, which sends out the selected rate to all the attached devices; when the rate switched at the Nanosyncs, all the devices automatically switch their rates to match.

Yamaha 02R

Yamaha 01V96