Yes. On a Mac you combine them into an Aggregate Device in Audio MIDI Setup, nominate one as the clock source and enable Drift Correction on the others. On Windows there is no built-in equivalent, so it takes a third-party ASIO wrapper. Either way the two interfaces run on separate clocks, so for multitrack recording the better answer is one interface with enough inputs — or an ADAT expansion on a box that has the socket.
The question usually arrives for one of three reasons: a third person joined the podcast, you bought a second interface before thinking about channel count, or you want to record and stream through different hardware. The answer is different for each, and only one of them genuinely needs two interfaces.
Why two interfaces drift apart
Every converter runs on a clock — a crystal oscillator deciding exactly when each sample is taken. Two separate boxes have two separate crystals, and no two crystals run at precisely the same rate. Over a minute the difference is microscopic. Over a thirty-minute interview it is enough for the two recordings to slide out of alignment, and the slide is not constant, so you cannot fix it by nudging one track.
That is the entire technical problem, and it is why professional multi-box setups are wired together with word clock or ADAT rather than simply plugged into the same computer. Clock first, channel count second.
On a Mac: Aggregate Device, with Drift Correction on
macOS has this built in. Open Audio MIDI Setup from Utilities, add a new Aggregate Device, tick the interfaces you want to combine, and set one of them as the Clock Source. For every other device in the aggregate, enable Drift Correction — macOS then resamples that device's audio on the fly to keep it aligned with the clock source.
Apple's own instruction is specific about the exception: if the devices are already synchronised to each other with word clock cables, you should leave Drift Correction off, because two correction mechanisms fighting each other is worse than either alone.
On Windows: no built-in option
Windows has no equivalent to Aggregate Device. An ASIO driver addresses one device, which is precisely why ASIO has low latency and precisely why it will not span two boxes. Your options are a third-party ASIO wrapper that presents multiple devices as one, or the shared Windows audio path at higher latency.
Both work and neither is pleasant. You add a software layer between your DAW and your hardware, and when something glitches mid-session you now have three possible culprits instead of one. If you record on Windows and need more channels, buy the channels. Best audio interfaces for PC covers driver quality, which matters more here than anywhere else in the chain.
What to look for instead
Three routes, in the order most people should consider them.
- One interface with enough inputs. Two mic preamps covers a host and a guest. Four covers a panel. This is the boring answer and it is right nearly every time.
- An ADAT optical input. A box with ADAT takes eight more channels from an external preamp unit over one cable, on one clock. No drift, no software layer, no aggregation.
- A dedicated podcast mixer-recorder. If the job is several microphones and no DAW, a purpose-built unit is simpler than any interface arrangement. RodeCaster Pro II vs Zoom PodTrak P4.
Interfaces that remove the need for a second box
Three boxes that solve the channel-count problem on one clock: four channels and MIDI, four channels with the most gain here, or two channels with ADAT to grow to ten.
MOTU M4
Top pickMOTU · Four channels, MIDI and the best converters here
The pick if you want MOTU's conversion plus MIDI and a couple of extra line inputs. If you only ever record one or two microphones and do not need MIDI, the M2 does the same job for less.
Why it is here
- 60 dB of published gain and `-129 dBu` EIN is a genuinely quiet channel, and unlike the M2 the figure is published
- MIDI in and out on a box this size saves a separate interface if you play keys
- Full-color LCD metering for all four channels, which is more useful daily than any software mixer
What it costs you
- 60 dB is enough for an SM7B but without much headroom to spare
- Two of the four inputs are line-only, so it is not a four-microphone box
- No onboard voicing or DSP at all
Focusrite Scarlett 4i4 (4th Gen)
Focusrite · The most gain, plus MIDI and loopback
The most complete interface under $500 for someone who records voice and plays keys and streams. If you do none of those extra things, the 2i2 has identical gain for less money.
Why it is here
- `69 dB` of gain, the same as the 2i2, so no microphone on this site needs a booster
- MIDI and loopback in one box — the two features that usually force a second purchase
- Four line outputs, so monitors and a separate headphone amp can both be fed
What it costs you
- Costs meaningfully more than the 2i2 for features a solo voice recordist may never touch
- Still only two mic preamps despite the four-in name
- Larger footprint than the desktop boxes
Audient iD14 MKII
Audient · 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
When two interfaces genuinely is the right setup
- Recording and monitoring on different hardware. One box captures microphones, the other feeds your monitors or a stream. Nothing has to stay sample-aligned between them, so drift is irrelevant.
- A second interface as a headphone amplifier. Perfectly reasonable, and an easy way to get a guest their own level.
- Devices already wired together with word clock or ADAT. Then they are not really two clocks, and this entire problem goes away.
- A stopgap. You own two boxes, a third person is arriving tomorrow and buying hardware today is not an option. Aggregate them, enable drift correction and record everyone to separate tracks.
What is not on that list is a serious multitrack session you intend to edit tightly. Two unsynchronised interfaces capturing one conversation is a repair job waiting in the edit, and the repair gets harder the longer the recording runs.
Practical checks before you try it
- Set both interfaces to the same sample rate before aggregating. Mismatched rates are the most common reason an aggregate device appears and then does not work.
- Record a test, long. Clap at the start and at the thirty-minute mark and check alignment at the end, not the beginning. Drift is invisible in the first minute.
- Use separate tracks per channel. If it does drift, per-track audio is salvageable and a stereo mixdown is not.
- Decide what your clock source is and leave it alone. Changing it mid-project invalidates everything you have already recorded.
And before any of that, check whether you actually need more inputs or more gain — they get confused constantly. More preamps do not make a quiet microphone louder. How much clean gain do you need separates the two problems, and best audio interfaces for multiple mics covers the channel-count side.