OK, here are my test results from RMAA with both the 1.50 and 1.70 firmware.
- RMAA generated a 32-bit FP / 192 kHz test file
- Connected MOTU M2 line out to F6 channels 1&2 with balanced TRS>XLR patch cables
- M2 output level set to max
- Played test file in Foobar while recording on F6 at 32-bit float / 192 kHz
- Recorded file from F6 transferred to PC and analyzed in RMAA to generate report
- These tests were NOT done in the same sitting, but conditions were identical
When looking at the Frequency Response data, make sure you scroll down to compare the 20 Hz - 20 kHz numbers in both documents, and not just the 40 Hz - 15 kHz numbers.
I find it curious that the noise floor in the new firmware is a bit higher, when performance is otherwise improved in other areas, especially the LF noise. I suppose there are always tradeoffs when choosing filters.
PDF files are below.
F6 1.50F6 1.70