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Focusrite Scarlett 2i2 (4th Gen) Interface Review

Rate this audio interface:

  • 1. Poor (headless panther)

    Votes: 26 18.6%
  • 2. Not terrible (postman panther)

    Votes: 73 52.1%
  • 3. Fine (happy panther)

    Votes: 39 27.9%
  • 4. Great (golfing panther)

    Votes: 2 1.4%

  • Total voters
    140
The Solo has classic analog gain control and is literally advertised as using "The classic Scarlett mic pre design.", so this seems unlikely.
If the Solo Gen 4 has a potentiometer for the volume control and uses the same circuitry as Gen 3 then that would be good news for those looking to measure as it would likely have the same preamp as Gen 3 but possibly a better ADC and/or DAC.

Anyway. Focusrite posted a comment on my review video saying that they're aware of this thread an of the issues with single-ended performance of the 2i2 Gen 4. They'll go and investigate. So maybe they'll have a fix. Who knows?

Tom
 
This thread is very interesting. I am currently testing two new, cost-effective audio interfaces: SSL 2 MKii and Topping E2x2.

This unanticipated journey started by my motivation for replacing a dead USB audio interface---EMU 0404 USB---that I've used for audio gear measurement for 16 years.

I narrowed down to these two products and ordered them---in fact, ended up ordering E1DA Cosmos ADC along with Scaler. But I still wanted to evaluate the SSL and Topping.

My main interest was in their ADC performance. The issue was with their unbalanced inputs through TS plugs. ADC of their balanced input was fine, although I was later spoiled by E1DA's performance :)

Initially I scratched my head, "what is wrong with unbalanced inputs?" I first suspected the cable quality, which was ruled out quickly. I was puzzled: How come unbalanced input ADC quality is much, much worse than balanced input ADC on both devices? The EMU 0404 USB had no such issue.

But then I recalledI had been using the 'ground lift' switch on 0404 USB without remembering its effect for so long. And searched this forum and found this thread. Turns out it is not just my experience.

I have been testing their ADC performance using a single laptop PC which is also connected to a DAC (Topping D50 III) used for signal generation. What would be the best way to break a ground loop in this case? I could use two separate laptops (battery-powered), one for generating tones and the other for measuring. Or use a USB isolator? Or use impedance balancing for unbalanced to balanced connection?
 
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I resolved a ground loop issue in my particular setup. Now, the noise floor of ADC with unbalanced input nearly matches that of ADC with balanced input. Just a tiny bit worse.

But have another question.

I keep seeing a clearly greater 2nd harmonic product from unbalanced input than from balanced input. And somewhat higher 3rd harmonic from balanced input than from unbalanced input.

I mean in exactly the same setup except for balanced vs. unbalanced connection. Why? I think I read a related comment somewhere but cannot locate it..
 
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I keep seeing a clearly greater 2nd harmonic product from unbalanced input than from balanced input. And somewhat higher 3rd harmonic from balanced input than from unbalanced input.
This is expected.

Even-order distortion (H2, H4, ...) is asymmetrical. With H2, a sinewave might get rounded off at the top but sharper at the bottom.

For a moment, let's a treat a balanced input like a pair of unbalanced ones, one of which is subtracted from the other. (Side note: That actually works decently if you need a mono balanced input in a pinch but unbalanced stereo is all you have. It often has to be done manually, but e.g. REW supports this for both inputs and outputs.)

Let's say they both distort the signal in such a way that +1 comes out as +0.9 and -1 comes out as -1.1.

Now we'll feed this input with a BTL signal: +1 becomes +1 on the hot leg and -1 on the cold leg. In an ideal distortion-free input, we would expect a differential of +1 -(-1) = +2.

+ input (hot): +1 in --> +0.9 out
- input (cold): -1 in --> -1.1 out
-----------------------------------
Differential: +0.9 - (-1.1) = +2.

The distortion has effectively been cancelled!

The same does not apply to odd-order distortion like H3, which you might see as symmetrical rounding of the sinewave tops. When both +1 and -1 become +0.9 and -0.9 equally, there is nothing the input can do about this. So you can only hope for H3 to not increase at best. It may go up the balanced signal is at higher absolute levels, including after the balanced receiver.

Note that while I have lumped together all the distortion in the input in this example, in general it's actually the product of the entire analog signal chain.
 
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This is expected.

Even-order distortion (H2, H4, ...) is asymmetrical. With H2, a sinewave might get rounded off at the top but sharper at the bottom.
Thank you so much for the enlightening. This makes perfect sense.

As you mentioned, this phenomenon should occur in the entire signal chain. In this particular case (DAC to ADC), the balanced design within a DAC w/ two DAC chips should be the main contributor because I'm comparing the DAC (D50 III)'s balanced (XLR) and unbalanced (RCA) outputs.

Speaking of a two-dac-chip design, based on what I've learned from your post, I think it's mostly a marketing gimmick. The major part of a DAC's performance should be from a good chip architecture and surrounding circuit design, not mainly from the use of two DAC chips differentially. Sure, using two chips may produce a tad lower noise floor and 3rd harmonics, lowering measured SINAD. But the difference shouldn't be audible. Anyway, current DAC technology way passed the limit of audibility..
 
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Overall I'd say this is likely a small upgrade over the previous generation even if the DAC is slightly, and likely inaudibly worse. The headphone amp, though still junk, is actually improved and possibly audibly so.

With that said, I'm surprised this interface remains so popular. My one attempt at a Focusrite interface ended after about 2 months: they stopped updating the drivers at the pace of the operating system and I couldn't use my interface. I assume they do better now. I couldn't give it away. I had a similar experience with EMU FWIW.

Good news is that I replaced the Focusrite with an Apogee Duet which gave me 10 good years and didn't have a driver issue until there was a processor typology revolution at Apple. The Apogee had considerably better preamps (dead silent and tons of gain) and headphone amp (lots of power), but was 6X the price. The Apogee was also far less user friendly with its breakout cable and it required you to have a window open to really see what you were controlling: a massive design fail in my book, but the sound and support kept me happy enough.

I could never buy another Focusrite product though. That lack of support ruined them for me. At least the Apogee worked and sounded fantastic.

Now I've got an IK Media Duet. It works perfectly and sounds good enough with the right headphones--MEZE Noir with Brainwavs ear pads which are very easy to drive. Its preamps are easily good enough for condenser mics and really good enough for dynamics. Not as outstanding as the Apogee, but good enough if you're careful with your gain settings. Best part is that it has real MIDI inputs/outputs.

If you're a hobbyist musician, I'm sure there are several interfaces that outperform this one in every way.
One of the success of Focusrite is simply the price, another maybe marketing: they acquired the reputation to be one of the best entry level interface for beginning the activity, and save some money for other gear…

As I see in @amirm list, Motu M2 is on the happy side, will be my next choice.

AFAIC the Scarlett is not audible in performances, but I record and play just for pleasure, perhaps in high-exigence professional world is not acceptable.

YouTube, Spotify and other internet platforms changed the edition and mixing world, now many people start a professional activity at home studio setups, and should be prudent when investing their money.

I’m curious for the RME babyface pro, do you know if has been measured?
 
I’m curious for the RME babyface pro, do you know if has been measured?

 

Thanks!

POST EDITED: very surprised reading Motu M2 values over RME babyface, that save me a lot of money since I was considering putting some money apart to the latest
 
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