With all the discussions about cables, I thought DeltaWave could be used to run a null-test comparison. Here's a quick test of three interconnects.
Equipment
Apogee Element24 in loopback mode @ 24/96k. Interconnects (DUTs): GLS Pro audio 6ft patch cable, Mogami Gold 6ft, and Monoprice AES/EBU 5ft cable.
Results
The first number is the RMS difference between the two captures, the second number is the correlated null, both in dB. Original2.wav comparison is the original digital file compared to the captured file with the specific interconnect:
With the largest RMS difference between Mogami Gold and GLS interconnects (-99dB), the two files match, bit for bit, for over 57% of all the samples in the two captures.
Discussion
Different interconnects appear to have a measurable effect on the captured audio.
Three captures were recorded using each cable, interleaving cables during the test to ensure external factors didn't unfairly affect any one cable. The loopback connection was using an XLR-terminated cable (DUT) inserted between Mic input and the line output of Element24. I used this audio file from the Gearslutz AD/DA evaluation thread. Audacity was used to capture the output from the ADC stage. DeltaWave was used to compare the captures.
THD+N for Element24 appears to be around -112dB, as in the below, off-the-screen photo. These are the same settings I used to run the null tests:
Equipment
Apogee Element24 in loopback mode @ 24/96k. Interconnects (DUTs): GLS Pro audio 6ft patch cable, Mogami Gold 6ft, and Monoprice AES/EBU 5ft cable.
Results
The first number is the RMS difference between the two captures, the second number is the correlated null, both in dB. Original2.wav comparison is the original digital file compared to the captured file with the specific interconnect:
With the largest RMS difference between Mogami Gold and GLS interconnects (-99dB), the two files match, bit for bit, for over 57% of all the samples in the two captures.
Discussion
Different interconnects appear to have a measurable effect on the captured audio.
- When each interconnect is compared to itself (yellow highlight) the values are pretty much at the limit of the DAC/ADC ability of Element24 to capture
- When compared to another interconnect, the nulls are 8 to 10 dB worse the RMS difference, but a smaller difference in the correlated null.
This means that the error is primarily in amplitude and not in timing/frequency - The difference between DAC/ADC captures and the original digital are significant (-42dB RMS) but very consistent across interconnects. The main effect here is obviously in the processing in the DAC/ADC and not due to interconnects.
Three captures were recorded using each cable, interleaving cables during the test to ensure external factors didn't unfairly affect any one cable. The loopback connection was using an XLR-terminated cable (DUT) inserted between Mic input and the line output of Element24. I used this audio file from the Gearslutz AD/DA evaluation thread. Audacity was used to capture the output from the ADC stage. DeltaWave was used to compare the captures.
THD+N for Element24 appears to be around -112dB, as in the below, off-the-screen photo. These are the same settings I used to run the null tests: