Shure
SM81
Small-diaphragm condenser · Cardioid · 20–20,000 Hz · a rider regular
- One of the genuinely flat live condensers — ±2.5 dB across the whole range, which is why it survives on hi-hat where a brighter mic turns to glass.
- A −10 dB pad and a three-way low-cut are on the barrel, so most of the fixing happens before the signal reaches the desk.
- Self-noise of 16 dB(A) was a studio figure in 1978 and is still quiet enough that nobody specifies a replacement for noise reasons.
Frequency response
Redrawn from Shure’s published response graph (approximate, ±2 dB) on the fixed MicSense scale — 20 Hz–20 kHz, −20 to +15 dB — so two microphones can be compared at a glance. No image is copied; it is a guide to the shape, not a measurement. Drawn for: low-cut flat (top curve); the two low-cut filter curves are not used. The maker’s graph (Frequency-response graph on the shure.com product page (image served from products.shureweb.eu)).
Polar pattern
Generated from the first-order directivity formula for cardioid. It illustrates the pattern type — it is not a measurement of this individual model.
Specifications
| Manufacturer | Shure |
|---|---|
| Model | SM81 |
| Type | Small-diaphragm condenser |
| Form factor | Stick / pencil |
| Polar pattern | Cardioid |
| Frequency range | 20–20,000 Hz |
| Sensitivity | 5.6 mV/Pa · -45.0 dBV/Pa |
| Max SPL | 136 dB SPL (1 % THD; 1 kHz, 1 kΩ load, attenuator at 0 dB) |
| Self-noise | 16 dB(A) |
| Impedance | 85 Ω (rated 150 Ω) |
| Connector | XLR3M |
| Powering | Phantom 11–52 V |
| Weight | 230 g |
Specifications: Shure datasheet · last checked 2 Oct 2026. These are the maker’s published figures for this model. A dash never means zero: “not published by the maker” means the maker’s documents give no figure; “not yet checked” means MicSense has not confirmed one yet. Spotted an error? Tell us.
MicSense notes
| Price tier | Pro |
|---|---|
| Introduced | 1978 |
Price tier and “a rider regular” are MicSense’s own judgement, not the maker’s.
What it gets used for
- Overhead
- Hi-hat
- Acoustic instrument
- Choir / ensemble
- Lectern / podium
MicSense tags microphones by the job on a live stage, not by studio category — so you can filter for “kick in” or “monitor vocal” instead of working backwards from “large-diaphragm condenser”.
SM81 alternatives: closest in published specs
Based on published specifications only — always listen at soundcheck. These are the microphones in the MicSense library whose datasheet figures sit closest to the Shure SM81’s for the same live job, with the reasons. It says nothing about how they sound.
-
Neumann
KM 184
- Same job: overhead, hi-hat, acoustic instrument
- Same type: condenser (small diaphragm)
- Same cardioid pattern
- Same form: stick / pencil
- Similar published response shape (≈ 0.5 dB apart on average, 100 Hz–10 kHz)
- Max SPL as high or higher (138 vs 136 dB SPL)
- ≈ 9 dB more output — about 9 dB less gain
-
Sennheiser
e 914
- Same job: overhead, hi-hat, acoustic instrument
- Same type: condenser (small diaphragm)
- Same cardioid pattern
- Same form: stick / pencil
- About the same output — within the datasheets’ tolerance
- Max SPL as high or higher (137 vs 136 dB SPL)
Not comparable: response curve not redrawn yet
-
sE Electronics
RN17
- Same job: overhead, hi-hat, acoustic instrument
- Same type: condenser (small diaphragm)
- Same cardioid pattern
- Same form: stick / pencil
- About the same output — within the datasheets’ tolerance
- Check: Max SPL 5 dB lower (131 vs 136 dB SPL) — check it on hi-hat
Not comparable: response curve not redrawn yet
Compare it against the alternatives.
MicSense lets you put up to four microphones side by side — spec table, overlaid response curves and polar diagrams on one screen. Free with a free Squaresmile account.