- Find out if Thunderbolt has the best connectivity
- Thunderbolt may be more future-proof devices, but are they for everyone?
- Is there really a big difference in latency between USB audio interfaces and Thunderbolt?
- Also, check out our post on the best Thunderbolt audio interfaces
USB and Thunderbolt audio interfaces are two popular choices for musicians and producers who need to record high-quality audio in their home studios.
Both interfaces have their own unique set of features and benefits.
Choosing any piece of digital audio recording equipment can often be confusing.
USB vs Thunderbolt is just one factor to consider when choosing the best audio interface, alongside the number of simultaneous inputs an interface can handle, the sound quality, and of course, your budget.
Until fairly recently, most audio interfaces would connect to your DAW or computer by USB, and everybody’s computer has one of them, right?
Then came along Thunderbolt–a new connectivity standard that promises more bandwidth and better speed.
But does an audio interface really need Thunderbolt? Let’s try and bust through some of that technical jargon to see if a Thunderbolt audio interface is worth the upgrade.
Thunderbolt vs USB Audio Interfaces (Is Thunderbolt Really Better?)
The short answer is YES, Thunderbolt audio interfaces are superior due to its lower latency. Thunderbolt also offers more bandwidth at higher speeds and therefore has a lower latency rate (the time it takes for your recorded input to reach the DAW.)
However, Thunderbolt audio interfaces tend to be more expensive, and not all computers or DAWs can connect to them. If you running an older Mac or PC, is it worth considering the upgrade to Thunderbolt?
What’s The Big Deal With Latency?
Although many differences between a USB and Thunderbolt audio interface are purely technical, the big difference is the speed at which they work.
Functionally both interfaces will do the same job, they may even offer the same sound quality and number of inputs, but a Thunderbolt interface will allow your DAW to process that data much quicker, known as latency.
Latency is how fast the audio interface can send the input signal (let’s use a keyboard signal as an example) through your interface’s pre-amp, A/D converter, onboard DSP, etc., and out to the computer before going back to your headphones or speakers.
The faster an audio interface can process that input signal through your computer, the less latency you will experience from the moment of striking that key on your keyboard to hearing it sound from your speakers.
Ideally, we would want no latency at all or 0.00 ms latency. Still, that original analog signal needs time to be processed by both the audio interface and the computer, which takes time.
At some point, almost every audio engineer has had to deal with latency issues.
It could be as simple as rigging up a mic to hit record and noticing a frustrating delay or, worse still, maybe a drum track or other input being out of sync with the other channels.
In many situations, this can seem impossible to work through.
Although latency in some cases can be an internal software error and caused by issues in the buffer size, when recording, a big part of latency problems can be the interface itself.
USB vs Thunderbolt Latency
Thunderbolt audio interfaces have improved the latency issues with the interface immensely.
A Thunderbolt audio interface will normally have a latency return of at least half the time of a similar USB audio interface and is as close to 0.00 ms latency as we can currently get.
The speed increases can lead to improvements in other areas, such as tracking while using plug-ins, which is especially useful in today’s digital era, where more and more virtual instruments are being used.
For example, linking up to a guitar amp with either a USB or Thunderbolt interface, you may not notice too much of a difference in latency.
However, the difference can be much more noticeable if you use an amp simulator. Not all USB interfaces will have a delay in scenarios like this, but in general, a Thunderbolt audio interface will offer noticeable improvements.
Let’s look at the exact figures with two practical examples of audio interfaces from Focusrite, one of the world’s leading manufacturers of audio interfaces.
USB 2 Focusrite Scarlett 2i2 (2nd Gen) @96 kHz/32-bit using
Round trip latency = 2.74ms
Thunderbolt Focusrite Claret2 Pre @ 97khz/32-bit using
Round trip latency = 1.67ms
USB 2.0 vs USB 3.0
Unfortunately, not all USB standards are the same. Regarding bandwidth and data transfer speeds, USB 2 and 3 can vary significantly.
USB 2 specifications state it can transmit up to 480Mbps of data using one channel.
This is plenty for most home audio setups, and you can record just over 40 tracks at a 24-bit, 96kHz sampling rate before you notice any discernable latency.
However, due to bus constraints and how the data is handled, the maximum transmission speed of even a well-designed USB 2 interface is more likely to be about 280Mbps.
Still enough to cope with 40 tracks at 24-bit, 96Khz, but once you start applying plug-ins, etc., it may struggle to keep up with the data flow.
Some manufacturers will also cater to higher sample rates, including 192 and 384 kHz, which can eat into the bandwidth.
Basically, every time you double the sample rate, you double the amount of data to be transmitted. Those 40 channels of audio at 96kHZ become about 20 at 192kHz and only ten at 384kHz.
USB 3 was released to try and alleviate the problem of restricted bandwidth and officially offers up to 5Gbps of data transmission.
Just like USB 2, though, hardware limitations often bring this down to just over 3.2Gbps–still over ten times the bandwidth of USB 2.
Here comes the big ‘BUT.’ Most Interface manufacturers have been very slow to adopt the USB 3 standard, and most of their audio interfaces still use USB 2.
For those increased bandwidths, the manufacturers have tended to choose Thunderbolt, especially the latest iteration of Thunderbolt 3.
The Rise of Thunderbolt 3
Just like USB, Thunderbolt has gone through several releases, the speed, and bandwidth increasing with each subsequent release.
The first release of Thunderbolt could handle up to 10Gbps of data, but on two channels, so, in theory, it could cope with 20Gbps.
Thunderbolt 2 was facilitated to handle 4K video streaming and other high-bandwidth applications, which could also handle up to 20Gbps but on a single channel rather than two.
The latest version of Thunderbolt, Thunderbolt 3, now boasts staggering transmission speeds of up to 40Gbps on a single flow.
To put that into perspective, your DAW and audio interface could now output a whole symphonic orchestra at a 192 kHz sampling rate on individual channels without any significant latency (providing your software and other hardware is up to the task!).
The reluctance of many hardware manufacturers to adopt the Thunderbolt standard (maybe they feel they had their fingers burnt by FireWire, Apple’s less successful attempt at high-speed data connectivity) means most have jumped in with Thunderbolt 3 technology.
Although USB 3.1 (2nd Gen) is emerging on more computers with data rates matching the 10Gbps of Thunderbolt 1, and USB 4 has been announced, which matches the 40Gbps of Thunderbolt 3, interface manufacturers have been very slow to adopt these standards.
It may still be a few years before we see USB 3.1 (2nd Gen) or USB 4-compliant interfaces.
Compatibility between an audio interface and the computer running your DAW is necessary to deliver a great recording.
It’s no good having the latest, most tech-equipped interface if your computer doesn’t recognize it or cannot communicate with it.
The “U” in USB stands for Universal Standard Bus, and you will certainly find a USB on nearly every computer.
Even Apple computers with only Thunderbolt ports nowadays can use USB-C cables and accessories (the same cannot be said about going backward from a Thunderbolt device to a USB-C interface always).
USB interfaces can come in different speeds (versions 2.0, 3.0, and 3.1) and normally have one of two connector types USB-A (the larger, older plug) or USB-C (the smaller, easier to plug-in reversible plugs often found on mobile phones).
Although the USB 3.0 standard can transmit more data at 5Gbps than USB 2.0 (480Mbps), USB 2.0 will still be powerful enough to power modest home studio setups for audio on your PC or laptop.
Some USB audio interfaces even have built-in processors and software, which are designed to compensate for the latency, but due to the design of USB, you will always find some latency with USB interfaces.
RME claims their latest USB 2.0 audio interfaces, such as the RME Fireface UCX II, can even stand up to the latest USB 3.0 and Thunderbolt devices with a built-in processor, which basically manages all the work of the interface.
For Windows or PC users, however, it can be extremely rare to find a Thunderbolt interface other than on some of the very high-end PCs.
If you are an Apple user, Thunderbolt is an absolute no-brainer. All Macbooks and iMacs since 207 have featured Thunderbolt ports, and the latest range now all carry at least one Thunderbolt 3 port.
Thunderbolt cables can even be used as USB-C cables, although not all USB-C cables can be used with Thunderbolt peripherals.
Currently the fastest data transfer protocol on the market, Thunderbolt 3 can transfer up to 40Gbps with short cable runs and up to 20Gbps with longer cables.
Thunderbolt is also bidirectional and can provide up to 8 lines of traffic via DisplayPort 1.2 connections.
And best of all, you can daisy-chain multiple Thunderbolt devices to one port, whereas every USB device needs to connect with its own cable to its own port or a hub.
The Downsides of a Thunderbolt Audio Interface
Basically, it comes down to what you are trying to link your audio interface up to at the other end.
If you are a PC user, you will struggle to find a PC that supports Thunderbolt technology.
Even if you were to find a Thunderbolt hub, once the data is transferred via the USB connection, it will throttle the speed and bandwidth down to the limited 5Gbps of the USB port.
Even USB-C only supports a maximum bandwidth of 5Gbps, and not all USB-C ports are compatible with Thunderbolt connections or devices (you can easily identify whether your USB port is compatible with Thunderbolt by a Thunderbolt logo next to the port).
As an Intel technology, you could always add a Thunderbolt card to your PC if it doesn’t already feature the Thunderbolt technology, but unfortunately, this is only an option for those PCs with an Intel Skylake or later chipset (circa 2016) and not available for AMD chipset PCs.
While some PC users may decide to upgrade their computer or switch to a Mac, for most, the extra expense can be off-putting, and a USB audio interface will work perfectly fine.
Not everybody wants to be locked into the Apple ecosystem, after all.
The other big difference between a USB and Thunderbolt audio interface is a non-technical one, the cost.
A USB interface will certainly be the cheaper option, and you can often find some excellent budget models for around the $100 – 150 mark.
If you are a PC user with no desire to switch over to a Mac or upgrade your computer, a USB audio interface is your best option which will serve you well and not require additional costs to upgrade.
If you are a Mac user looking to save some money by going with a USB interface, this is where it gets more tricky.
Most Macs now only have Thunderbolt connectivity, and as we said earlier, not all USB peripherals are compatible with the Thunderbolt protocol.
If you only have Thunderbolt connectivity on your Mac, you will need to buy some sort of USB hub.
As an additional expense, this probably won’t deter most, as buying that extra hub will still be cheaper than buying a Thunderbolt audio interface.
In conclusion, both USB and Thunderbolt audio interfaces have their own unique set of features and benefits.
USB audio interfaces are affordable, widely available, and compatible with Mac and Windows operating systems. This makes them popular for beginners and hobbyists.
Thunderbolt audio interfaces offer faster transfer speeds and lower latency, making them popular for professional musicians and producers who need to record high-quality audio in real-time.
In terms of data speed, Thunderbolt 3 is one of the fastest technologies available, and it looks like it will be the data transfer method of the future.
It’s already acknowledged by many to be the gold standard of both home and professional recording, and investing in a Thunderbolt audio interface is about as future-proof as your studio setup can get.
Ultimately, the choice between a USB and Thunderbolt audio interface will depend on the specific needs and budget of the user.