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
Read off Shure’s published response graph and re-drawn on the fixed MicSense scale (20 Hz–20 kHz, −20 to +15 dB), so two microphones can be compared at a glance. Points between the entered coordinates are interpolated — no data has been invented to smooth the curve.
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 |
| Self-noise | 16 dB(A) |
| Impedance | 85 Ω (rated 150 Ω) |
| Connector | XLR3M |
| Powering | phantom 12–48 V |
| Weight | 230 g |
| Price tier | Pro |
| Introduced | 1978 |
Every figure above is from Shure’s own published datasheet for this model — see the datasheet. A dash means the manufacturer does not publish that figure; it does not mean zero.
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”.
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.