sE Electronics X1 S on a Volt 176: “30 mV / Pa (−31 dBV)” — the two halves of that line disagree by half a decibel
sE prints both units on one line, but 30 mV/Pa is −30.5 dBV, not −31. It is half a decibel and it moves the required gain by a whole one — a small, checkable example of why a converted number should never be quoted as if it were measured.
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: 29 dB of the Volt 176's 55, with 26 dB spare — and the microphone is quieter on paper than its own millivolt figure says.
The numbers. sE prints Sensitivity 30 mV / Pa (-31 dBV). At 85 dB SPL the printed −31 dBV/Pa puts −37.8 dBu on the cable; the Volt 176 clips at +9 dBu, so a −18 dBFS take needs 29 dB. Take the millivolt figure instead — 30 mV/Pa converts to −30.5 dBV/Pa — and the requirement is 28 dB. Half a decibel of rounding in the datasheet becomes a whole decibel on the gain knob, because the number gets rounded a second time on the way out.
Which one this page uses. The printed dBV figure, because that is what sE published as a specification rather than as a conversion. It is also the conservative choice: assuming the microphone is 0.5 dB quieter than it may be costs you nothing, while assuming it is louder would silently shave your headroom estimate. But you should know the discrepancy exists, because you will see both numbers quoted as if they were the same number.
The rest of the sheet is unusually complete. Electrical impedance 125 Ohms, Recommended load impedance >1k Ohms, Powering 48V Phantom Power (P48 according to IEC 61938), Max SPL 140 / 150 / 160 dB (0 / 10 / 20 dB pad), self-noise 9 dB. That load line is the one most makers omit, and it is what lets you check the X1 S against a load-switching booster or a transformer input instead of guessing.
The gem. Engaging the X1 S's −20 dB pad turns it, for gain-staging purposes, into a −51 dBV/Pa microphone — arithmetically the same output as a Shure Beta 58A, which needs 49 dB on this same Volt 176. So the pad does not merely buy you 20 dB of SPL headroom; it moves the microphone from the easiest quarter of the preamp's range into the same territory as a loud dynamic. With 55 dB available you still have six decibels in hand, which is why the −20 dB pad is usable here and would not be on a 50 dB interface.
What to do: one XLR cable, +48 V on, gain around 29 dB, pad off for voice. Reach for −10 dB before −20 dB: the first pad keeps you at 39 dB of gain, well inside the preamp's comfortable middle.