This is a review and detailed measurements of the Focusrite Scarlett 2i2 Audio Interface (DAC/ADC). I was talked into buying it recently. The 2i2 costs US $140 including free Prime shipping so very reasonable for amount of functionality.For a budge device, the Scarlett 2i2 looks pretty good:Yes, I have left the plastic cover on the front and back.Leaving it there in case I decide to sell the unit.I found the controls more logical than Behringer budget products. Like the separate volume control (small one) for headphone and the larger one for the line out for example.The inputs are kind of strange in that depending on what type of cable you use, the gain changes. If you use XLR, it assumes microphone input and hence higher gain. If you use TRS/1/4 inch plug, then it assumes "line" input. This works but you better have the right cables to mate with it this way.The back panel doesn't have much other than a USB-C jack that I like and TRS line outs:Note: I spelled Scarlett wrong in all the graphs below. Too lazy to edit them all now.Let's test each subsystem independently starting with DAC:This is pretty good! We actually beat the company spec by good bit. Max output is I think 4.6 volts so this is not a powerhouse like higher end audio interfaces are.SINAD of 102 is enough to place the Scarlett 2i2 in our competent bucket:Dynamic range is good enough for 17 bits or so:Noise level is not competitive with better desktop audiophile DACs though:Jitter test shows the same elevated noise level but otherwise clean:Linearity is near excellent:Multitone shows increasing distortion with frequency:Filter response is more or less one expects from default DAC chip settings:We hit what is a seemingly major snag with we test at much higher bandwidth of 90 kHz:Measured distortion+noise goes through the roof, rising to as much as 0.3%! Is the 2i2 this bad? Yes, and no. Let's first perform a wideband spectrum analysis of a 1 kHz tone:Noise level sharply rises above 28 kHz. This is a feature of many DACs where noise in audible band is pushed into ultrasonics. The levels though seem low rising to "only" -85 dB. But that is misleading because FFT analysis artificially lowers the noise output of the device under test. Let's use a simple noise meter and see what we get:At default 22.4 kHz I use for the dashboard measurement, the noise level is 25volts (millionth of a volt). Increase the bandwidth to 90 kHz to capture the noise shaping and that value jumps 650 times higher to 16.3volts (thousands of a volt).Fortunately we don't hear ultrasonics and even if we did, this is pretty low level so it is more of a bother for our eyes in measurements than ears.Jumping right into the heart of the matter with THD+N versus power into 300 ohm we get:This is no good. We are getting power levels that we can get out of a smartphone or a $9 dongle attached to it.The situation doesn't improve with 33 ohm load:Now we have tons of distortion in addition to low output level.Thankfully output impedance is low:Digitizing analog inputs is the main purpose of these interfaces so let's see how we do with a 1 kHz tone at 2 volts using XLR connection (i.e. "mic"):This is quite good actually, once again landing the 2i2 into the competent bucket:The above required gain settings at minimum so I thought I test the line input using TRS jacks:Gain was lowered but distortion actually increased! Not sure why.Either way, you can't use professional levels of 4 volts or more as you can with higher end products. 2 Volts is it.Dynamic range is good with 2 volts in and near 0 dBFS capture:Frequency response is very flat and nice, albeit stopping early on 192 kHz:Linearity shows the better noise performance of XLR/mic input:THD+N versus level shows the superiority of the Scarlett 2i2 compared to consumer interfaces:Test using "jitter" signal (j-test" shows clean but elevated noise level:1 kHz FFT spectrum shows the same:A bit of oddness in THD+N versus frequency:I can see why the Focusrite Scarlett 2i2 is such a popular audio interface. Its DAC and ADC both deliver competent performance with no dark corners. The only item performing well below expectation is the headphone amplifier. If you care about headphone monitoring, best get a proper amplifier to pair with it. With a single output though this may be a bit challenging.Overall, I had low expectations going into this review and came out pleased. I--------As always, questions, comments, corrections, etc. are welcome.I understand getting Christmas presents for your pets is "a thing" now. With two dogs and half a dozen panthers, this bill adds up big time. So I appreciateusing : https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/