Which Interface?

26 Jul 2013

Firewire, USB and Thunderbolt explained

An initial consideration is what ports are available on your computer. Traditionally, Apple Mac computers have offered Firewire, which is uncommon, but not unknown on Windows computers and both offer USB. However Firewire sockets are disappearing from Mac computers as time goes by, to be replaced by Thunderbolt interfaces. Meanwhile, USB 3 is becoming more popular, especially on PCs. At present, Focusrite offers Firewire and USB interfaces, but Firewire interfaces will work seamlessly with Thunderbolt via an adaptor.

Keep Audio interfaces and external hard drives on separate busses

 Your choice of audio interfaces will also be related to what external devices your system already includes. The fundamental consideration is to determine which bus your hard drives are on – and use a different one for your interface (Thunderbolt is an exception here: see below). The drives in an audio system are active at exactly the same time as your interfaces, taking the bandwidth you will need for audio, so it makes sense to put drives and audio interfaces on two separate buses. If you’ve followed Pro Tools compatibility requirements, in a Mac system you’ll have your drives hooked up via Firewire; on a Windows machine, they’ll be connected via USB – so, simply, use the other bus for your audio interface, or install a separate interface card to give you an additional bus with its own controller, completely separate from any other. Fundamentally: your hard drives and your audio interfaces need separate buses.


This consideration is complicated by the gradual replacement of Firewire ports with Thunderbolt on Mac systems. Thunderbolt is an external form of PCIe, and is very fast with low latency. It also offers a great deal of capacity – you can easily run both audio interface and drives via Thunderbolt. However, if you only have one Thunderbolt port and you already have a device such as a display or drive connected, there will be nowhere to attach another device unless one of them offers a second port for daisy-chaining. Luckily, both non-Firewire Apple Mac computers and Thunderbolt drives tend to have dual Thunderbolt ports,.

Use an external power supply with Thunderbolt

Another consideration is power. Thunderbolt ports will only provide a maximum of 12W or so, and not all of that is available. While it may be possible to run some smaller Firewire interfaces via a Thunderbolt to Firewire adaptor without, we recommend the use of a power supply with any Firewire interface connected to a Thunderbolt port. It should be noted that the performance of a Firewire interface running via a Thunderbolt adaptor is neither compromised nor enhanced.

What external hard drive should I buy?

USB 3 is now starting to appear on computers, and external USB 3 drives are available. USB 3 offers wide bandwidth, although it is not as fast at Thunderbolt. If you are starting from scratch, you may have the choice of attaching your drives to one or the other. If you buy Thunderbolt drives, they will include power supplies anyway and they will connect direct to the bus. If you choose a Firewire audio interface, you will need a Thunderbolt adaptor and a power supply if you intend to connect it via Thunderbolt.

Ethernet Audio Interfaces

Focusrite also offers the RedNet range of interfaces that connect via Ethernet. Typically, the connection to the computer is via a special PCIe card. Thunderbolt is essentially an external PCIe bus, and card frames are available for connecting PCIe cards to a computer via Thunderbolt. Drivers are expected to become available for the RedNet PCIe card to run in such a frame, so this potentially provides a further interface option – and, of course, virtual soundcard drivers are available enabling RedNet interfaces to be connected to a computer’s standard Ethernet port.