IMP Box

Imp Box Front 3



  • constant voltage source measurements
  • extremely accurate voltage and current data
  • perfect for speakers and components
  • measuring levels up to 2500W (based on a 4Ohm load)
  • 3 different level ranges (0dB, -20dB and-40dB)
  • balanced analyzer outputs
  • ultra high precision current shunt resistors
  • very lightweight and portable






The IMP Box is a very useful small accessory. With the IMP Box you can easily measure the voltage and current during a frequency sweep. By dividing the two measurements after the sweep you receive an impedance measurement under constant voltage conditions. That means that you are able to measure the system or speaker under real conditions. To prevent damage to your analyzer when measuring with high power, the Imp box provides 3 different selectable output ranges. 0 dB, -20 dB and -40 dB.

By using an analyzer with 3 input channels you can perform a SPL and Impedance measurement with a single sweep and any level you want. Up to 2500W for a 4Ohm load! This is very usefull if you want a cheap and fast QC system. All you need is a laptop with your analyzer software and soundcard, 2 mini power amplifiers and the IMP Box.

Not for use with bridged amplifiers!


The IMP-Box works with Clio, LMS, EASERA, Audio Precision APx and many other analyzers...


rear view:

Imp Box Rück2



IMP-Box Manual


Application Note for Clio Users:

AN Audiomatica Clio

Application Note for Audio Precision APx Users:

AN Audio Precision APx




Max Power Table


    0dB Mode (1Ω) ; max 2,5A   -20dB Mode (0.1Ω) ; max. 8A -40dB Mode (0.01Ω) ; max. 25A 
 Load max. Voltage  max. Power    max. Voltage max. Power     max. Voltage max. Power  
 2Ω  5V 12,5W  16V  128W 50V  1250W 
 4Ω 10V  25W  32V  256W  100V  2500W


 37,5W  48V  384W  150V  3750W
 8Ω  20V  50W  64V  512W  200V  5000W