Buy the SSL 2+ MKII if anyone else is ever in the room: two independent headphone outputs and 64 dB of published mic gain make it the safer choice for a two-person recording or a low-output dynamic. Buy the MOTU M2 if you record alone and care most about conversion and metering — -129 dB EIN, 120 dB of output dynamic range and a full-color LCD meter on the box itself.
These two are the usual shortlist once you have decided a $150 interface is not enough, and they are not differentiated by sound quality in any way you will hear. Both convert well beyond what a domestic room will reveal. What separates them is what is printed on the specification sheet and what is physically on the front panel.
The gain figure MOTU does not publish
MOTU states an equivalent input noise figure of -129 dB, which is excellent, but does not publish a maximum mic gain. The SSL publishes 64 dB. That matters because you cannot plan a microphone purchase against a number that does not exist.
If your microphone is a condenser or a hot dynamic — anything at -55 dBV/Pa or better — this is a non-issue and the M2's quiet preamp is a genuine asset. If your microphone is a Shure SM7B at -59.0 dBV/Pa, you want a published figure you can check, and 64 dB clears it without a booster. The Scarlett 2i2 publishes 69 dB and costs less than either of these, which is why it keeps appearing in this conversation.
Two headphone outputs is the feature that decides most of these
If you ever record with a guest, a co-host or a vocalist in the room, they need to hear themselves, and a single headphone output means a splitter, a mismatched level and a session spent apologizing. The SSL's two independent outputs solve that outright — each gets its own level control.
It is worth being blunt about how much that is worth: for a two-person podcast it is the whole comparison. Everything else here is a refinement. Two-person podcast setup covers the rest of the chain, and best audio interfaces for multiple mics ranks the field for more than two.
Both interfaces, and the cheaper box with more gain
SSL 2+ MKII
Top pickSolid State Logic · Two headphone outs and a console voicing
Buy it for the second headphone output if you record with anyone else in the room — that single feature is worth the premium. For solo work the 2i2 gives you more gain for less money.
Why it is here
- 64 dB of gain clears an SM7B without a booster
- Two independent headphone outputs is the feature that makes a two-person recording workable
- The 4K switch is a real, usable top-end lift rather than a marketing mode
What it costs you
- Costs meaningfully more than a 2i2 for 5 dB less gain
- Four outputs are wasted if you only own one pair of monitors
- Larger footprint than the rest of this group
MOTU M2
MOTU · The best converters and metering at the price
The pick if you care most about conversion quality and want to see your levels without alt-tabbing. If your mic is an SM7B and you want a published gain number you can check against the mic's sensitivity, the 2i2 is the safer buy.
Why it is here
- -129 dB EIN is genuinely quiet, and it shows on low-output dynamics
- Full-color LCD metering on the box is more useful day to day than any software mixer
- Independent phantom power and monitor switching per input
What it costs you
- MOTU does not publish a maximum mic-gain figure the way Focusrite does, so gain headroom is harder to plan around
- No onboard voicing or DSP at all
- Loopback needs the software, not a front-panel switch
Focusrite Scarlett 2i2 (4th Gen)
Focusrite · The most gain per dollar in a two-input box
The default answer for someone buying an SM7B or PodMic: it supplies enough clean gain that you never need a booster, which makes it the cheaper total purchase even when it is not the cheaper box. Look elsewhere only if you need MIDI or four outputs.
Why it is here
- 69 dB is the most gain of any interface at this price, and enough for an SM7B with headroom to spare
- 120 dB dynamic range means the converters are not the weak link
- Two inputs, so a second person does not mean a second purchase
What it costs you
- Air mode is a fixed voicing, not an EQ you can dial
- Plastic-and-metal build feels less solid than the SSL or Audient competition
- No MIDI, which matters if you also play keys
What the M2's metering is actually worth
A full-color LCD meter on the interface sounds like a gimmick and is not. It shows input and output levels at a glance, without a software mixer, without alt-tabbing out of your DAW and without trusting a three-LED traffic light to tell you how close to clipping you are.
Day to day, on solo work, that is the single most useful thing about the M2 — more useful than the converters, which are better than your room. Pair it with the ESS Sabre32 DAC on the output and 120 dB of output dynamic range and you have the best listening chain of the two, which matters if the same box also feeds your studio monitors.
The 4K switch, honestly
SSL's Legacy 4K switch is a per-input analog top-end lift and a touch of harmonic drive, modeled on their large-format consoles. It is a real effect, not a marketing mode, and on a dull-sounding dynamic it can be genuinely flattering.
It is also printed permanently into the recording. That is the trade with every piece of color on the way in: you are committing now to a decision you would otherwise make later, where you can change your mind. For spoken word, record clean unless you know exactly why you are not. Audio interface vs preamp covers where color belongs in the chain.
Which to buy
- Solo work, condenser or hot dynamic, you want the best listening chain: MOTU M2.
- Anyone else in the room, ever: SSL 2+ MKII, for the second headphone output.
- Your microphone is an SM7B or similar low-output dynamic: the SSL's published 64 dB, or the Scarlett 2i2's 69 dB for less money.
- You need MIDI: neither. Best audio interfaces with MIDI covers that instead.
Neither of these is a mistake, which is the useful summary. They are both a clear step past the budget tier in build, routing and documentation, and the decision is about your room rather than their sound. If you are not sure the step up is justified at all, are cheap audio interfaces worth it is the more honest first question.