Shure SM7B and a MOTU M2: how much gain does the M2 actually have?
MOTU publishes an EIN of −129 dBu for this preamp and no gain range at all. Speech asks the SM7B for 58 dB. This page says what can honestly be concluded from that, and what cannot.
Signal Chain Compatibility Matrix
Select gear and parameters for live gain, impedance and SPL calculations.
Input Equipment Setup
PASS: Optimal Signal Chain
Requires minimum +60dB of clean pre-amp gain. Most budget entry interfaces max out at +50dB to +56dB and introduce hiss at max pot. An inline preamp booster (Cloudlifter CL-1 / FetHead) is strongly recommended.
The interface preamp provides sufficient headroom.
$538
$405
-25%Tonal & acoustic characteristics: Flat, wide-range frequency response for clean music and speech. Smooth, warm acoustic character with air-suspension shock isolation.
Technical advisory: With +69dB max gain, the Gen 4 Solo can drive demanding dynamics like the Shure SM7B natively without requiring an external inline booster.
Physical Interconnect Topology
Shure SM7B
Direct Cable Connection (No Intermediate Box)
1x Shielded Balanced XLR Cable (3-Pin XLR Male to XLR Female)
Focusrite Scarlett Solo (Gen 4)
Host: Apple MacBook Pro (M1/M2/M3/M4)
Short answer: nobody outside MOTU knows, because MOTU does not publish it — and this page will not invent the number.
What is known: at 85 dB SPL a hand away, the SM7B delivers about −65.8 dBu. The M2's converter clips at +10 dBu, so a −18 dBFS target needs 58 dB of preamp gain. What is not known is how far the M2's knob goes. Its spec sheet lists an EIN of −129 dBu, a +10 dBu maximum input, 192 kHz, a 3.27 V headphone output — and no gain range. The calculator on this page therefore falls back to an assumed 50 dB and marks the result as assumed. Treat that flag as the answer: an assumption, not a measurement.
If you already own the M2, you can settle it in two minutes. Speak at your normal level and distance, turn the gain fully up, and read the meter. If peaks land near −18 dBFS, you have all the gain you need. If they land at −26, you are 8 dB short and an inline booster fixes it.
The thing worth knowing: EIN is not gain, and it is quoted as if it were. Equivalent Input Noise is measured with the gain at maximum and a 150 Ω resistor on the input; it tells you how quiet the preamp is when it is working hardest, not how far it travels. An interface can have a class-leading EIN and still run out of range on a broadcast dynamic. When a manufacturer publishes the noise figure and withholds the gain figure, the honest reading is that the gain figure is not the one they wanted printed.