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MOTU M4: enable only the documented microphone phantom supply

MOTU M4: enable only the documented microphone phantom supply. Check prerequisites and the actual response before reporting an outcome.

Manufacturer-documented Reviewed 2026-11-09 · Revision 1

Follow these checks in Audio Fix →

When this guide applies

Compatible XLR microphone already connected; required channel 48 V known off.

Connection scope: Analog line / headphone audio. Symptom: My microphone isn’t working.

This is a documented check, not a diagnosis of your equipment. The model name does not confirm the selected input, mode, software or connected partner.

If your exact model or a required setting is unknown, use the “I don’t know” branch below. Do not apply a similarly named model’s instructions.

Checks and possible outcomes

Start at step-0. Follow the link that matches what you actually observe. Alternative branches are not a single sequence of actions.

step-0

Does the exact microphone manual require and permit 48 V phantom power?

Unknown compatibility or a passive ribbon stops here; jack inputs are not phantom microphone inputs.

Look for: Confirm the actual prerequisite or observation. Unknown stops safely.

  • Manufacturer-documented MOTU M4 official user guide ↗PDF pages 8, 18, 19 — The exact M2/M4 quick reference identifies input gain, red overload boxes, independent headphone volume, per-channel 48 V, power switch and USB bus power. Headphones mirror Monitor 1–2.Exact model/generation named in this manual; external controls and documented host paths only. · Source checked 2026-11-09

step-1

Is it already connected to the intended XLR channel?

No hot-plugging is part of this flow.

Look for: Confirm the actual prerequisite or observation. Unknown stops safely.

  • Manufacturer-documented MOTU M4 official user guide ↗PDF pages 8, 18, 19 — The exact M2/M4 quick reference identifies input gain, red overload boxes, independent headphone volume, per-channel 48 V, power switch and USB bus power. Headphones mirror Monitor 1–2.Exact model/generation named in this manual; external controls and documented host paths only. · Source checked 2026-11-09

step-2

Is that channel 48 V off, with recording stopped and listening levels down?

No blind toggle of an unknown state.

Look for: Confirm the actual prerequisite or observation. Unknown stops safely.

  • Manufacturer-documented MOTU M4 official user guide ↗PDF pages 8, 18, 19 — The exact M2/M4 quick reference identifies input gain, red overload boxes, independent headphone volume, per-channel 48 V, power switch and USB bus power. Headphones mirror Monitor 1–2.Exact model/generation named in this manual; external controls and documented host paths only. · Source checked 2026-11-09

step-3

Lower that input gain before the power change

Leave other input power and gain untouched.

Look for: Perform only the stated operation, then confirm whether it could be completed.

  • Manufacturer-documented MOTU M4 official user guide ↗PDF pages 8, 18, 19 — The exact M2/M4 quick reference identifies input gain, red overload boxes, independent headphone volume, per-channel 48 V, power switch and USB bus power. Headphones mirror Monitor 1–2.Exact model/generation named in this manual; external controls and documented host paths only. · Source checked 2026-11-09

step-4

Engage only the corresponding 48 V button

Do not connect or disconnect the microphone while phantom is active.

Look for: Perform only the stated operation, then confirm whether it could be completed.

  • Manufacturer-documented MOTU M4 official user guide ↗PDF pages 8, 18, 19 — The exact M2/M4 quick reference identifies input gain, red overload boxes, independent headphone volume, per-channel 48 V, power switch and USB bus power. Headphones mirror Monitor 1–2.Exact model/generation named in this manual; external controls and documented host paths only. · Source checked 2026-11-09

step-5

Does the microphone show signal after gain is gently restored?

An enabled supply alone is not proof of captured audio.

Look for: Confirm the actual prerequisite or observation. Unknown stops safely.

  • Manufacturer-documented MOTU M4 official user guide ↗PDF pages 8, 18, 19 — The exact M2/M4 quick reference identifies input gain, red overload boxes, independent headphone volume, per-channel 48 V, power switch and USB bus power. Headphones mirror Monitor 1–2.Exact model/generation named in this manual; external controls and documented host paths only. · Source checked 2026-11-09

Possible result

Checks completed — report what happened

Completion is not an automatic solved result. Report solved, partly helped, did not help or could not follow based on your actual observation. No Audio Review physical test is claimed.

steps completed

Reaching this result does not mean the issue is solved. Only your own feedback can report improvement.

    Possible result

    Keep these observations for official support

    A required prerequisite or response was not confirmed. Stop this sequence and use the exact model and partner documentation. Do not escalate to a factory reset, firmware installation, internal repair or unsafe wiring change.

    next support

    Reaching this result does not mean the issue is solved. Only your own feedback can report improvement.

      Possible result

      A required fact is unknown

      Confirm the exact model, connection, partner capability and current control state before continuing. Do not guess settings or operate an updating product.

      insufficient data

      Reaching this result does not mean the issue is solved. Only your own feedback can report improvement.

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