Belles Ondes : Creative Engineering

This document proposes a test procedure and results comparing Behringer XR18 and Midas MR18 performance.

Starting with a general statement: Measurements are done as close as possible to what would be a scientific measurement process (Configuration and tests are documented, are reproducible by a third party, tests results are published, known assumptions and limitations are mentioned as far as possible).

Now the claims:

• Statement #1 : Measurements are done in recording studio environment. Namely, there is no control on CEM/EMI interfering with measurements apart from standard studio installation best practices in terms of proper ED grounding and shielding.
  • As a consequence, comparing the results is more important that dealing with the RAW value.
• Statement #2 : One input and one output are used on each unit, there is only one pair of interface sample tested. Having a pair allows to check for a similar performance on both interface, to rule out obvious erroneous failures on one interface. It is understood that statistically processing those measurement among several interfaces and unit S/Ns would be much better, but is out of scope of this measurement procedure.
  • As a consequence, these results are (1) immune to critical failures on one channel but are (2) prone to specimen bias.
• Statement #3 : XR18 has two high impedance instrument inputs which MR18 does not have. For the sake of comparing apples with apples, Input 9/10 and Output 1/2 are used as references on both units.

Measurement Gear

• UUTs
  • MR18 S211000533C8H
  • XR18 XXXXXXXXXXXX
• Tools
  • Gen2 Apollo Twin USB
  • XLR Wires / Jack Adapters
  • Room EQ Wizard Rev xxx for measurement

Measure loopback RTA THD (+N) @1khz + total dynamic range.

• REW in loopback mode,
• Double shielded XLR as connection
• on both units, use In-9 and Out-1

Loopback diragram:

• Set Inputs Gain to 0dB
• Set Output level to match a -12dBfs input level
• Measure RTA and store

• Set Inputs Gain to 8dB
• Set Output level to match a -12dBfs input level
• Measure RTA and store

• Set Inputs Gain to 18dB
• Set Output level to match a -12dBfs input level
• Measure RTA and store

• Set Inputs Gain to 28dB
• Set Output level to match a -12dBfs input level
• Measure RTA and store

• Set Inputs Gain to 0dB
• Set Output level to match a -12dBfs input level
• Measure Transfer function and store

• Set Inputs Gain to 8dB
• Set Output level to match a -12dBfs input level
• Measure Transfer function and store

• Set Inputs Gain to 18dB
• Set Output level to match a -12dBfs input level
• Measure Transfer function and store

• Set Inputs Gain to 28dB
• Set Output level to match a -12dBfs input level
• Measure Transfer function and store