Pair of (2) Matched Primo EM4052PMI4
Condenser Microphones
(Bruel & Kjaer Style)

Although there is one mic in the photograph, this auction is for two.
Each microphone comes with its own Calibration Data Sheet (below)



Impedance: 1k ohms +/-30%
Sensitivity: -45dB +/-2.5dB ct 1kHz (RE 0dB + 1v/Pa)
Frequency Response: Flat (70 incidence within limits)
Directional Characteristics: Non-directional
S/N Ratio: 32dB S.P.L. max.
Operating Voltage: 4v
Supply Current: 250 uA max
Distortion:  Below 135oB 1.5% max
                 Below 132oB 1% max
                 Below 122oB 0.5% max
Max Input Sound Level: 148dB S.P.L.



We have quite a few of these mics. We will try to select pairs that have a closely matching frequency response.

Each microphone comes with its own case




As our many customers will attest, we will do our very best to resolve any customer problems.  But our official policy is: 

  • All items sold carry a 3-day Right Of Return Warranty. 
  • All claims must be made within 3 days of receipt. 
  • All warranties are void if the calibration / warranty seals are broken.

Shipping Policy

Shipping to be determined depending on geographical location.  We will make every effort to ship within 24 hours of receipt of payment.  We ship with FedEx only.  We will be glad to ship with other carriers using the purchasers shipping account.  Please contact us to make any special shipping arrangements. For shipping rate research, our shipping address is Boulder, CO USA ---- Zip Code is 80305.

Foreign Buyers:  Unless special provisions have been made, you are responsible for making your own shipping arrangements and all costs related to customs, duties & special packaging requirements.  Please do not ask us to quote you international shipping rates.  Use the address information above to research you own shipping rates.  You can email to get the packaging fee, package weight and size for your research.  Items sold outside the USA are sold as is.  

Payment Policy

We accept Credit Card payment through Paypal.   We accept Cashiers Check or Money Orders.

Ascent Concepts and Technologies
is a Research & Development Lab.  As a service to the companies and institutions we work with, we broker their excess equipment & act as application specialists on their new equipment needs.  We are now offering quality used equipment to the public with the same level of professionalism and service.   Please feel free to email at or call Thomas @ 1-303-554-0307 with any Technical questions.  Please feel free to email at with any Shipping or Logistical questions. We make every effort to evaluate and guarantee our equipment.  Although we do not provide NIST traceable calibration, we do have extensive in house calibration equipment and make every effort to test and verify performance on equipment we sell.  However we do not warranty any items shipped outside the United States. 



The equipment shown is a representation only.  We often have multiple units in stock so please email us with your needs.  We have a large inventory and can usually find any test and measurement item in a short time frame.------Inquires