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Module based USB measurement Microphone 1/2" ATD5-T 

 

 

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Please note that this package includes the USB Pre-amp without capsule

This new ATD5-T USB Microphone is the improved version of the ATD4-S. It has improved frequency range and dynamic. Due to it's internal DC/DC converter it can handle up to 10VRMS and +/-14V peak. With a typical 50mV/Pa capsule you can reach up to 143dB Peak SPL.

At the buttom of this description you will find the full datasheet and an example measurement with our audio analyzer APX555 from Audio Precision. We also added some recordings to demonstrate the superior low noise.

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With this USB measurement microphone you can easily perform high performance measurements with your PC. Simply connect this microphone to a free USB port, no preamplifier, no external power no driver.

It was never easier to measure with your PC.

This is what you expect from a modern PC measurement system.

In many classical solutions, the problem occurs that the number of possible sources of error is quite high. An arbitrary combination of soundcard with microphone.  Is the preamp overloaded, the capsule, or the AD converter?. 
Anybody, who owns a collection at various USB soundcards knows the "fiddling" (check wiring, Windows Drivers, phantom power, level setting, the Windows Mixer adjustments  etc.).

These are things you should not consider today

In general, the new USB measurement microphones work with all measurement programs on the market. Only, the level calibration calibration feature is available in specially designed systems.


The advantages of such solutions are:

  • Setup is much easier, no phantom power, no drivers, etc.
  • Simply connect it to the USB port.
  • With appropriate software, these systems are calibrated directly.You can measure absolute sound level sound.
  • Calibrated measurement range selection via software
  • Cable lengths up to 60m
  • All parts of the signal chain are matched to each other.
  • Measuring ranges are instantly recognizable.

A USB measurment microphone contains the following components

  • pre-polarized condensor capsule 1/2" or 1/4"
  • impedance converter
  • pre-amplifier
  • digital controlable attanuator
  • AD-converter
  • USB interface
  • power supply converter

All parts are integrated into the body of the microphone. This makes the system very compact. Since there exist only the USB interface connection, cabling is very easy.

This system uses capsules with the thread 60UNS. You can connect almost any capsule from world leading brands. e.g. Bruel&Kjaer, GRAS, PCB and others.
With common mechanical adapters you can use 1" or 1/4" capsules. You can also connect class 1 capsules.

Features

  • We offer a Windows ASIO driver which has a full dynamic of 15-143dB on one channel without switching the range
  • Gain is controlled by the PC allowing absolute level calibrations
  • Requires no external power. Simply connect it to USB
  • The operating system recognizes this USB microphone directly. There is no driver required. You can use this USB measurement microphone with Windows, MacOS or Linux. This feature will protect your investment, since you not depend on updated drivers.
  • We offer this system with different options (different capsules or dynamic extension)

This measurement microphone uses a real 1/2" capsule with 12,7mm diameter. Many simple measurement microphones use a cheap 1/4" caspsule (6mm) in a 1/2"-housing. The effective area of the diaphragma is 4 times smaller. This leads to significant higher noise.
The following picture demonstrates a 1/2" capsule in contrast to a 1/4"-electret capsule.

1/2" usb mic capsule vs. 1/4"

Common characteristics

  • Frequency range 5Hz-20kHz option 90kHz
  • Thread 60UNS
  • USB Audio class compliant
  • possible cable lengths: 5m with simple passive USB cables, 15m with active cables and 60m with special transceivers for regular CAT5 cables
  • max input voltage 10V RMS +/-14V peak
  • Dynamic 15dB(A) to 143dB (peak)
  • dual channel conversion with 40dB offset
  • The self noise of the amplifier and AD converter is 10dB(A)
  • USB bus powered
  • Micro-USB connector

Listening tests

Setup: We put a mechanical clock 50cm in front of the microphones

  1. Behringer ECM8000, very cheap measurememnt microphone with XLR connector and 48v phantom power. Due to the small diaphragma the noise level is very high around 34dB(A)
  2. MiniDSP UMIK-1, cheap USB microphone with similar capsule compared to the ECM8000. The clock is audible, but with strong noise.
  3. ATD5-T The advertised USB Microphone with 1/2" class 1 capsule (50mV/Pa) Selfnoise around 15dB(A) caused by thermal noise of the capsule
  4. G.R.A.S. 40HL, an extreme low noise measurement microphone 1/2" with 200V polarisation voltage. This is the reference class. Selfnoise is around 5dB(A). Such system cost around 6000Euro. You can find the datasheet here

 
 
Electrical Measurement Protocol with Audio Precision APX555 Download
Datasheet Download