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Rational Acoustics RTA-420

Regular price $89.00
Regular price $89.00 Sale price $89.00
Shipping calculated at checkout.


The RTA-420 is an ideal budget-friendly measurement mic. It’s a great choice if you’re a student, just starting out with system measurement, an established pro looking for a backup mic, or putting together a "B" rig. It’s also a cost-effective solution for multi-mic measurement setups. The RTA-420 offers very respectable frequency response, heavy-gauge steel construction, and measurement performance to rival high-end microphones costing many times more.

The RTA-420 has a relatively low maximum SPL, so it is not ideal for critical or concert-level SPL measurement applications, however it is still capable of generating accurate data at modest levels. Where critical SPL measurement is an important factor, consider purchasing at least one microphone that is better suited for SPL measurement and reserve the RTA-420’s for your spatial frequency response measurements.

The Rational RTA-420 comes with a mic clip and a bright yellow windscreen, which is great for spotting your mic in dark venues. It also includes a custom-designed soft carrying case that accommodates and organizes 2 microphones plus accessories.

NOTE: The Rational RTA-420 is PIN 3 HOT and requires the 10mm calibrator adapter for use with the iSEMcon SC-1 Microphone calibrator.

Key Features:

  • Capsule: ¼” Electret Condenser (housing diameter at capsule: 10mm)
  • Polar Pattern: Omnidirectional
  • Frequency Response Characteristic: Diffuse Field (Random Incidence)
  • Frequency Range: 20 Hz – 20,000 Hz
  • Nominal Sensitivity: 7 mV/Pa, +/-3 dB typical
  • Operating Voltage: 9-52V DC Phantom Power
  • Max SPL: approx. 110dB (1 kHz @ 1% THD)


  • 1 RTA-420 Microphone
  • 1 soft-sided dual-mic carrying case
  • 1 mic clamp
  • 1 windscreen