Buy the Audient iD4 MKII if you will only ever record one microphone at a time — it has the same Class-A preamp, the same 58 dB of gain and the same -129 dB(A) EIN as its bigger sibling, for considerably less. Buy the iD14 MKII if you need a second simultaneous microphone input, or want the ADAT optical input that grows the box to ten channels later. Neither has enough gain for a Shure SM7B without a booster.
This is the cleanest comparison on the site, because there is no sound-quality argument to have. Audient puts the same discrete Class-A console preamp in both, publishes the same -129 dB(A) equivalent input noise for both, and caps both at 58 dB of gain. You are buying channel count and expansion.
58 dB is the number that matters, and it is the same on both
Audient's preamps are among the quietest you can buy at this price — -129 dB(A) EIN is a figure you would expect a tier up, and the iD14 adds a published 100 dB(A) signal-to-noise figure on the mic pre to back it up. What neither of them has is headroom for a low-output dynamic.
A Shure SM7B publishes -59.0 dBV/Pa, which in practice wants around 60 dB of clean gain for spoken word at a normal distance. 58 dB gets there with the knob at the end of its travel and nothing left in reserve — which is exactly the situation an inline booster exists to fix, at the cost of another box and another cable. Work the arithmetic before you buy: how much clean gain do you need and how much gain does the SM7B need.
Pair either of these with a condenser, a Rode PodMic at -57 dBV/Pa or a Shure SM58 at -54.5 dBV/Pa and the gain ceiling stops being a conversation. That is the pairing these boxes are built for.
What the second channel is actually for
Two mic preamps means two people talking at once into separate tracks, which is not the same thing as two people sharing a microphone. It also means a microphone and an instrument, or a stereo pair on an acoustic guitar. If any of that is in your plans within a year, buy the iD14 now — a second interface later is the most expensive way to get a second channel.
What it is not for is louder. Two preamps do not add gain. If your problem is a quiet microphone rather than a second source, the answer is a different interface entirely — best audio interfaces for the Shure SM7B lists the boxes that publish enough.
Both Audients, and the box with the gain they lack
Audient iD14 MKII
Top pickAudient · The quietest two-channel preamp pair here
The best-sounding two-channel box in this price band, and the right buy if your microphones are condensers or hot dynamics. With a low-output broadcast dynamic the gain ceiling still forces a booster.
Why it is here
- Two of the same Class-A console preamps as the iD4, at `-129 dB(A)` EIN
- ADAT input means it grows to ten inputs without replacing the box
- JFET instrument input that takes being driven hard
What it costs you
- 58 dB is marginal for an SM7B, exactly as on the iD4
- No MIDI, which at this price is a real omission
- ADAT expansion needs a separate preamp unit you do not own yet
Audient iD4 MKII
Audient · The best-sounding single preamp here
The right box if your mic is a condenser or a hot dynamic and you want the cleanest single channel at this price. If you are buying an SM7B, 58 dB puts you straight back into booster territory.
Why it is here
- -129 dB(A) EIN and 0.0017% THD+N are numbers you would expect a tier up
- The Class A preamp is the same circuit family as Audient's consoles
- Two headphone outputs on a one-input box, which is unusual and useful
What it costs you
- 58 dB is not enough for an SM7B without a booster
- One mic input only
- No onboard DSP or voicing
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
ADAT: the feature that makes the iD14 a ten-year purchase
The iD14's ADAT optical input accepts eight more channels from an external preamp unit. That is the difference between an interface you replace when your needs grow and one you add to — a four-person podcast, a drum kit, or a band tracking live all become possible without touching the box on your desk.
The honest caveat: that external eight-channel preamp is a real purchase you do not own yet, and it costs more than the interface does. ADAT is insurance, not capacity. Treat it as a reason to prefer the iD14 at the same price, not as a reason to pay a large premium for it. Can you use two audio interfaces at once explains why the ADAT route is the one that actually works.
Both have two headphone outputs, which is unusual
Worth noting because it cuts against the obvious logic: the single-input iD4 has two headphone outputs. So a guest can hear themselves even on the one-channel box — they just cannot be recorded to their own track. For an interview where you only need one voice captured well and the other person needs to hear, that is a usable arrangement and it saves real money.
Which to buy
- One microphone, forever, and you want the best single channel at the price: iD4 MKII.
- A second simultaneous microphone, or a plan to grow: iD14 MKII, for the second preamp and the ADAT input.
- Your microphone is an SM7B or similar: neither — 58 dB is not enough. Look at the Scarlett 2i2's published 69 dB.
- You need MIDI or loopback: neither. Best audio interfaces for streaming covers loopback.