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Microphone Input Noise Comparision
The various manufacturers of portable audio recorders often use different and confusing specifications for their products that might prevent an reliable and objective evaluation of their capabilities for recording soft animal sounds in the field.
This page provides more homogeneous specifications across the different recorder models. Details on the relevant properties of a recorder in conjunction with a specific microphone are available on the page Understanding microphone and recorder/preamplifier noise specifications.
Other details on the properties of the recorders are available in the tutorial on Sound Recording in the Field.
Noise levels at the maximum available gain settings
|
Equivalent Input Noise (EIN)
impedance: 150 ohms |
Input Clipping Level (2) |
Dynamic Range (3) |
|
| A-weighted |
unweighted
20Hz - 20kHz |
dBu |
mVrms |
A-weighted |
| SoundDevices 722 |
-130dBu
(-130dBu) |
-128dBu
(-128dBu) |
-46dBu |
3.8mV |
84dB |
| Tascam HD-P2 |
-127dBu |
-125dBu |
-40dBu |
7.7mV |
87dB |
| Fostex FR-2LE |
-129dBu |
-125dBu |
-45dBu |
4.3mV |
84dB
(85dB) |
| Marantz PMD671 |
-125dBu |
-123dBu |
-50dBu |
2.4mV
(1.2mV) |
75dB
(65dB) |
| Marantz PMD670 |
-120dBu |
-118dBu |
-52dBu |
1.9mV
(1.2mV) |
68dB
(65dB) |
| Marantz PMD660 |
-120dBu |
-118dBu |
-52dBu |
1.9mV
(1.2mV) |
68dB
(60dB) |
| KORG MR-1000 |
-117dBu |
-115dBu |
-46dBu |
3.8mV |
71dB |
| Olympus LS-10 |
-121dBu |
-119dBu |
-51dBu |
2.0mV
|
70dB
|
| Marantz PMD620 |
-112dBu |
-110dBu |
-40dBu |
7.7mV |
72dB |
| Tascam DR-1 (MIC 1 IN) |
-111dBu |
-109dBu |
-41dBu |
6.9mV
|
70dB
|
| Tascam DR-1 (MIC 2 IN) |
-115dBu |
-113dBu |
-28dBu |
31mV
|
87dB
|
| M-Audio MicroTrack II (1/4" input) |
-101dBu |
-99dBu |
-41dBu |
6.9mV |
60dB |
| M-Audio MicroTrack II (1/8" input) |
-106dBu |
-104dBu |
-46dBu |
3.8mV |
60dB |
| M-Audio MicroTrack 24/96 (1/4" input, +27dB) |
-115dBu |
-113dBu |
-48dBu |
4.4mV |
67dB |
| M-Audio MicroTrack 24/96 (1/8" input) |
-109dBu |
-107dBu |
-32dBu |
19mV |
77dB |
| Edirol R-09 |
-106dBu |
-104dBu |
-41dBu |
6.9mV |
65dB |
| SONY HiMD MZ-RH1 (4) |
-124dBu |
-122dBu |
-64dBu |
0.49mV |
61dB |
| SONY DAT TCD-D3 |
-117dBu |
-115dBu |
-56dBu |
1.3mV |
61dB |
| INA163-based preamp |
-130dBu |
-128dBu |
|
|
|
| Measurement conditions: |
Recording format: 44.1 KHz, 16 bit, mono (left channel). All parameters were measured at the maximum available gain setting. Limiter and noise cancel options were disabled. Note that a bit-depth of 24 bit would not improve the noise level figures at these high gain settings.
When available, the figures in brackets indicate the manufacturer's specifications.
|
|
The errors of the measurements should be less than +-2dB |
| 2: |
The input (clipping) level at the maximum available gain setting represents the maximum input sensitivity of the recorder. 0 dBu is equivalent to 775 mVrms. Note that the dB gain figures that are often specified by the manufacturers do not represent a meaningful characterization of the relevant input sensitivities that would be needed in practice. |
| 3: |
The dynamic range at the maximum available gain setting alone should not be interpreted as an indicator for the performance of a recorder because these numbers will also depend on the absolute input level (overall gain). |
| 4: |
The MZ-RH1 measurements were done by John Beale. |
|
The calculation and filtering procedures were executed by using the Avisoft-SASLab Pro sound analysis software, version 4.39. |
Noise Performance Test Sound Files
In order to evaluate the noise performance of the various recorders in combination with different microphones, the sound of an electronic alarm clock has been recorded subsequently with three different microphones and various recorders.
All recorders were set to their maximum gain. The test arrangement was fixed throughout the entire test procedure (the distance between the clock and the microphones was 1 meter).
The columns labelled "normalized" contain the normalized sound files. In order to compensate for the different input sensitivities of the various recorders, the normalization was done in such a way that all files exhibit a virtual input clipping level of -60 dBu (the original files were digitally amplified according to the previously measured input clipping levels listed above).
Note that this kind of normalization does not compensate for the different microphone sensitivities. So, for evaluating the absolute equivalent noise levels of the various microphones, their sensitivities must be taken into account (50mV/Pa : 40mV/Pa : 25mV/Pa = 0dB : -2dB : -6 dB).
The columns "original" contain the original and unmodified 16 bit .wav files. The last two seconds of each file represent the inherent noise floor of the recorder (the microphone input was terminated by a 150 ohms resistor).
|
Sennheiser K6/ME66
50mV/Pa, 10dBA
noise floor: -110dBu |
Sennheiser MKH60
40mV/Pa, 8dBA
noise floor: -112dBu |
Rode NT1-A *
25mV/Pa, 5dBA
noise floor: -118dBu |
|
normalized |
original |
normalized |
original |
normalized |
original |
| SoundDevices 722 |
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| Tascam HD-P2, 16 bit |
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| Tascam HD-P2, 24 bit |
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| Marantz PMD671 |
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| Marantz PMD670 |
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| Marantz PMD660 |
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| M-Audio MicroTrack 24/96 |
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| Edirol R-09 |
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* The Rode NT1-A studio microphone has been added to this comparison only for reference purposes in order to demonstrate the influence of the microphone specifications on the overall noise performance.
Due to its large size, the relatively low directionality, the high sensitivity to moisture, mechanical shock and wind noise, this microphone model is not recommended for mobile sound recording of individual animal vocalizations in the field.
Due to the incompatible phantom power voltage of the M-Audio MicroTrack 24/96 (30 Volt only), the MKH60 microphone provides a very poor noise floor with that recorder.
See also the illustrated noise floor comparison of the various recorders and microphones.
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