Following on from his recent review of the PreSonus HD7 headphones, in this article Paul Dormer takes a closer look at PreSonus’ iTwo iSeries audio interface.

The iTwo is a 2-in-2 out, 24 bit / 96Khz capable USB interface in a rugged brushed aluminium desktop case. It’s light, due to the lack of internal power supply but looks and feels pretty tough. This is handy, as portability is one of it’s key features. This is a dual purpose device which can be used with either a Mac/PC or iPad, but not at the same time. Using the supplied Capture Duo software you can record to an iPad, then later wirelessly transfer your session to the included Studio One Artist package on your Mac or PC. Unofficially the iTwo also delivers functionality to some other iOS devices. I had no problems capturing audio with a number of applications on an iPhone 4S for example.

The front panel houses two combo inputs, independently switchable between line level or instrument on 1/4in jack, or microphones via XLR. The mic preamps are a Class A design with switchable 48V phantom power and up to 52dB of gain. You can use the inputs in any configuration. Phantom power is however switchable for both mic inputs simultaneously. A headphone output with plenty of guts is conveniently located on the front panel adjacent to it’s own discrete volume control, and a large dial controls the main output levels. All the knobs are notched. On the rear you have two main outs, MIDI in and out, USB and iPad connectors. A Kensington lock hole provides the option to secure the device should you happen to be in a public space.

This is a class compliant device and on the Mac no software installation is required – you simply plug it in and it works. On the PC side a quick driver installation provides an applet for adjusting buffer size and sample rate. Compared to my usual interface – which incorporates a fiendishly complex mixer – routing and basic metering is performed manually using the hardware controls. It’s simple. Two LEDs on the front panel light green for peak levels, blinking red if the unit clips. Given the 24 bit dynamic range this is a fine arrangement, and setting suitable input levels is child play. Many applications of course offer more precise internal metering.

Beyond form and function my first concern with a device like this is sound quality. The Class A mic preamps are worth a mention as they are definitely a big draw for this device, quieter and richer sounding than those found on typical budget mixing consoles. The PreSonus extracted a lot of performance from microphones. The box also worked well as a direct input box, producing good character from guitar and bass.

I’ve used the iTwo as my primary audio interface for a few weeks and compared it subjectively to a number of other sources, including outboard DACs and sound cards. As a HIFI enthusiast listening on revealing Focal JM Lab monitoring the fact it has remained in situ for this period of time can be taken as a compliment. To confirm my subjective impressions and compare to on-paper specification I performed some basic sound quality tests using the RMAA utility. For this price point, I found nothing to quibble about. It’s neutral, with a flat response and a healthy 103dB dynamic range. This unit is capable of delivering high quality sound with a forgiving 24 bit headroom allowing a large margin of error for beginners.


A full analysis of the RMAA test can be read here.

Something else I wanted to look at was latency a key issue for musical performers. In audio interface terms, this is the time it takes for a signal to make the round trip from the input, through the computer (including any software in the signal path) and back to the outputs. The problem with higher latencies is it creates a disconnect between the performer and their actions. As a rule of thumb latencies of 12ms or better are desirable. To give some context, sound travels at just over 1ft per millisecond so a guitarist standing 7ft from their cabinet will experience a latency of approximately 7ms. That’s acceptable, but double the distance might be problematic. Latency is inevitable in audio interfaces which need to employ buffers. As with other manufacturers PreSonus have sought to redress the issue, so the iTwo has a mix control which allows you to sweep between direct input (zero latency) and thru the computer monitoring. An excellent solution. There are however circumstances in which full loop back monitoring may be desirable. In order to test the iTwo I used the RTL utility (Windows 8.1/32bit) which reported a latency of 5.602 sec using a 64 bit buffer. Excellent!

In addition I decided to perform a real world test, routing a microphone signal into Studio One, applying a channel strip EQ with low mid and hi settings and recording the resulting round trip signal simultaneously with the dry input. [3,1 Mac Pro, Yosemite, 32 bit buffers @ 96kHz]. The measured distance between the two resulting waveforms was 671 samples, around 7ms. Hats off to PreSonus they’ve done a first class job here. This low latency performance gives a distinct advantage in situations where you need to add just a little EQ or similar to your dry signal whilst recording. For anything more intensive, a sound card with onboard processing would be recommended, such as PreSonus’ own VSL series interfaces.

To summarise, the iTwo’s main virtues are high performance audio in a versatile, simple to use portable interface you can chuck in a bag (padded!) and move between computers and iOS devices. It’s a solid all rounder and I thoroughly recommend it. If I was being petty, I might complain about the lack of visual feedback from the knobs, or the customary blinding LEDs. I do not take issue as some have with the iTwo requiring a USB power supply to work with an iPad. That is a consequence of USB specification I’m afraid. The situation is the same with all similar devices of this class.

So who is the iTwo aimed at? PreSonus marketing suggests “mobile musicians, sound designers, and podcasters”. I would go further. The ability to record from a variety of line level sources, stereo and mono, synths, hi-fi equipment, guitars, microphones, combined with MIDI capability lends itself to a myriad of possibilities. More than this, PreSonus is offering an integrated solution. There are a plethora of video tutorials, news feeds, promotions, an even the iTwo manual offers 20 pages of insightful commentary on microphone types dynamic processing and equalisation. The iTwo also integrates seamlessly with Studio One, PreSonus digital audio workstation software for Mac or PC. The bundled Artist version is extremely generous inclusion, as it retails for £79 alone. It also warrants closer inspection, and to that end in the next review I will be taking a closer look at this piece of software.

The HD7 and all the iSeries products are available from UCan Play through our status as an approved PreSonus educational dealer. Discounts are available for those at or working with educational institutions within the United Kingdom.