I’ve recently uploaded a new Thingiverse project: 35° XLR adapters designed to streamline near-coincident stereo recording specifically for use on my shiny new Zoom M4 MicTrak. These lightweight, push-in adapters angle your XLR mics outward by 35°, enabling a 110° stereo angle between microphone, which when used with cardioid mics, is the same angle as the ORTF stereo technique.
While originally designed for the M4, this solution also works with any recorder where the XLR inputs are positioned on opposite sides of the chassis. The result is a compact, one-handed stereo rig with clean cable paths, solid repeatability, and no need for stereo bars or extra mounting gear. Not to mention the ability to just stick the whole thing on a tripod and record.
Designed for One-Handed ORTF Recording
The idea behind this adapter is: when each mic is angled 35° outward from the recorder’s centerline, the total angle between capsules is 110°, which matches the standard ORTF configuration. That makes this adapter pair ideal for achieving the proper pickup angle for natural spatial imaging based on the ear’s typical pattern.
However, due to the physical width of the recorder body (which is true with any recorder where the inputs are on opposite sides from each other) and the added connector offset, the spacing between mic capsules will be wider than the ORTF standard of 17 cm. This doesn’t compromise the recording in most real-world scenarios, but it does slightly widen the stereo image for nearby sources. As the sound source moves further away, that difference becomes negligible, and the setup behaves almost identically to standard ORTF.
In short: you get the correct angle, with slightly more spatial width for near-field recordings, and faithful stereo imaging at distance, for lots more ease of use.
When I started getting into field recording I used spaced omni pairs almost exclusively, and was almost never satisfied, so I dug into trying other things.
A Brief Overview of ORTF Stereo
ORTF (named after the Office de Radiodiffusion Télévision Française) is a near-coincident stereo microphone technique that uses:
- Two cardioid microphones
- Capsule spacing of 17 cm
- An angle of 110° between microphones
The goal is to mimic human hearing by combining interaural time differences (ITD) and interaural level differences (ILD), producing a stereo image that is spacious, realistic, and mono-compatible. It’s a favored choice for environmental recording, acoustic music, dialogue, and soundscape work.
Why Use These Adapters?
Using these 3D-printed 35° XLR adapters allows for:
- Exact 110° mic angle with no measuring or adjusting
- Tool-free, fast setup directly on the Zoom M4
- No stereo bar or rigging required
- One-handed use while walking, operating gear, or monitoring
- Cleaner cable routing with less strain on jacks
They’re especially useful for minimalist field rigs or mobile workflows like my every day carry. Wires kind of kill the whole quick dopamine hit.
Why the Zoom M4 is an Ideal EDC
These adapters were designed specifically for the Zoom M4 MicTrak, whose symmetrical side-mounted XLR jacks are ideal for this configuration. Despite a somewhat rocky launch (more on that below), the M4 has become a reliable, capable, and compact recorder — especially well-suited for stereo field recording.
Key Strengths of the M4:
- 32-bit float recording – no gain staging, no clipping, no missed takes, turn it on and push the button
- Built-in timecode generator and sync – unusual for a recorder this size, and perfect for syncing to video for ambiance recordings (I usually use either an Osmo Pocket 3 or a Sony A7Siii, both of which have great timecode support
- Built-in X/Y mics – Use them to grab a quick sound
- Physical controls, fast startup, and intuitive operation
Early criticism of the M4 focused on EMI (electromagnetic interference) noise in some units. Zoom responded quickly and responsibly, offering replacements to affected customers. Newer units have been completely free of this issue and rock-solid in performance. Now that the device is effectively discontinued though, the $200 price point really makes it stand out.
When paired with these adapters and a small matched mic pair (e.g., cardioid condensers or hypercardioids), the M4 becomes a powerful one-piece ORTF stereo rig that you can hold in one hand or mount on a compact stand in seconds.
I started using a pair of Rode M5s, but they had their own issues and have since upgraded to the super quiet, and also slightly discontinued Rycote CA-08 mics.
Compatible with Other Recorders
While the Zoom M4 was the design target, this adapter pair will work with any recorder where the XLR jacks are mounted on opposing sides of the unit. The XLR jacks are aligned and set in the correct position with a set screw, so I can quickly change these to be compatible with my Zoom F6 too.
Final Thoughts
Field recording is all about capturing the moment without fumbling through setup or gear. This small design solves a very specific, real-world problem: how to achieve ORTF stereo with no rigging, no measuring, and no compromises using just your handheld recorder and a mic pair.
Download the files on Thingiverse, print them in under an hour, and throw them in your kit. If you record with the M4 or a similar device, I think you’ll appreciate how these clean up your workflow.
I’d love to hear how you’re using them — what gear you’re pairing them with, and what you’re capturing in the field.
Happy recording.
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