Earthworks Audio
Earthworks QTC40
Small-diaphragm condenser, omni (pressure), measurement-style tapered body; 3 Hz to 40 kHz
Power Phantom 24-48 V.
- Type
- Condenser (electret)
- Pattern
- Omni
- Sensitivity
- −29 dBV/Pa
- Among 204 condensers: more output than 95%
- Among 311 mics: more output than 96%
- Self-noise
- 20 dB(A)
- Among 258 condensers: quieter than 23%
- Among 272 mics: quieter than 23%
- Max SPL
- 140 dB SPL
- Among 277 condensers: takes louder sound than 62%
- Among 343 mics: takes louder sound than 56%
- Rated range
- 3 – 40k Hz
vs 75 end-address condensers
More output than 92% of 75 end-address condensers.
Each stripe is one end-address condenser with a published sensitivity, and each bar counts them; further right means more output. This mic is in blue.
vs 104 end-address condensers
Quieter than 19% of 104 end-address condensers.
Each stripe is one end-address condenser with a published self-noise, and each bar counts them; further right means quieter. This mic is in blue.
vs 110 end-address condensers
Takes louder sound than 64% of 110 end-address condensers.
Each stripe is one end-address condenser with a published max SPL, and each bar counts them; further right means it takes louder sound. This mic is in blue.
Instruments sources recommend it for most
Proximity effect: the bass it gains up close
From the manual (Recording Hacks copy), p. 2.
Fig. 2 "Frequency Response (Typical) of QTC40" in the 2005 owner's manual; relative dB, 3 dB per division. A smooth "typical" curve; distance and room not stated.
Dashed: outside the rated range, or simulated (other angles and distances). Hover or tap the graphs for values.
Polar pattern
From the graph polar, p. 1.
Image "QTC-Series-Polar-Pattern-2022" on the QTC40 product page (the file name says QTC series); each frequency drawn on one side only (1 and 5 kHz left, 10 and 20 kHz right), taken as symmetric. Measuring conditions not stated.
In practice
All specs
| From the user guide | ||
|---|---|---|
| Self-noise | 20 dB(A)also 22 dB(A), 2005 manual. "20dB SPL (A weighted)". The 2005 manual: "22dBA equivalent". | p. 4 |
| Max SPL | 140 dB SPLpeak acoustic input; also 142 dB SPL, 2005 manual. "Peak Acoustic Input 140dB SPL"; no THD figure. | |
| Output impedance | 65 ohmbalanced between pins 2 & 3; also 100 ohm, 2005 manual: 50 ohm each pin 2 & 3 | |
| Rated load impedance | 600 ohmminimum, balanced between pins 2 & 3 | |
| Rated frequency range | 3 Hz to 40 kHz+1/-3 dB; also [4, 40000], ±1 dB, 2005 manual | |
| Powering | phantom 24-48 V"24-48V Phantom, 10mA". The 2005 manual: "48V Phantom, 10mA". | |
| Current draw | 10 mA | |
| Weight | 225 g"225g (.5lb)". | |
| Dimensions | 22 × 229 mmDiameter × length: "229 x 22 mm (9 x .860 in.)". | |
| Supplied accessories | microphone clip; calibration chart"Your purchase includes". | p. 2 |
| From the manual (Recording Hacks copy) | ||
| Capsule | pressure (omni), prepolarised condenser | p. 2 |
| Calibration chart | Each microphone comes with its own chart of its individually measured frequency response | |
| Proximity effect | None ("It exhibits no proximity effect") | |
| Removable parts | None; the microphone cannot be opened | |
| ApplicationsEarthworks, 2005 | Quieter sources: vocals, strings, woodwinds, distant-miked orchestras or choirs; a matched pair for classical location recording | |
| From the product page | ||
| Sensitivity | −29 dBV/Pa (34 mV/Pa)typical; also −30.5 dBV/Pa, 30 mV/Pa, 2005 manual (converted). "34mV/Pa (-29dBV/Pa)" (20·log10(0.034) = -29.4). The 2005 manual says 30 mV/Pa (typical). | p. 1 |
| Connector | XLR-3 male (pin 2 +)"XLR (pin 2+)"; the user guide says "XLR-3". | |
Documents
- QTC40 Omnidirectional Room Microphoneuser guide, May 2022
- QTC40 — Omnidirectional Condenser Microphone | Earthworks Audioproduct page
- QTC40 frequency response graphproduct page image, 2022
- QTC series polar pattern graphproduct page image, 2022
- QTC40 Omnidirectional Microphone Owner's Manual2005
Copies kept by Mic Archive (manufacturers move and drop their documents), unchanged, with their original addresses. Each is © its publisher.
Recommended for
By recording guides, engineers and mic makers, for this mic or an earlier version of it.