- Written by Stephen Hornbrook and Chris Heinonen
- Published on 21 February 2013
On the Bench
The Meridian Explorer DAC was tested using a MacBook running BitPerfect over iTunes as a source to make sure nothing was resampled or otherwise sent at anything than the original bitrate. From there the fixed line output was fed to a Lynx Two card on a PC running SpectraPlus to provide the data analysis.
On a 1 kHz test tone with CD quality audio, distortion is very low at 0.001% THD+N. Even order harmonics are larger than odd order ones, but even those are well over 100 dB below the fundamental frequency.
With a 10 kHz tone, the THD+N rose to 0.0014%, but we still have very close to 100 dB of dynamic range available here, and a very low noise floor that is over 120 dB below the fundamental.
With 60 Hz and 7000 Hz IMD test tones, the IMD is very, very low at 0.0006%, and if there is a 14 kHz harmonic, I can't see it. The noise floor is still over 120 dB down, offering really excellent performance.
With 19000 Hz and 20000 Hz IMD test tones we do finally see some sidebands that are visible, and a little B-A peak down at 1 kHz. That peak is almost 100 dB below the test tones, but the sidebands are only around 80 dB down. It is still very nice, but not as amazing as the first couple of tests.
Stepping up to 24/96 Test Tones, we see a bit more THD+N with the 1 kHz test, and there is a bit more noise present in the spectrum as well. Once again the even harmonics are more prevalent than the odd harmonics. The main reason for the noisier looking spectrum is that the noise floor is now down below 130 dB instead of 120 dB, letting more actual noise be visible.
The 10 kHz tone shows slightly different results, with the odd harmonics being more prevalent than the even ones, and THD+N rises up to 0.0038% this time. Overall the noise floor is very low, but the 10 kHz peak itself is a little slower to raise and fall.
Once we move up to 24/96 on the 60-7000 IMD test we can see the 14 kHz spike, it was just obscured by the noise floor before. It won't be any more relevant this time, as it is still over 120 dB down, but it does exist. IMD remains incredible low, just like it was at CD resolution.
With the 19000-20000 IMD test the results also look the same, only with a lower noise floor. The A+B peak is present and visible but around 90 dB below the primary tones.
Moving up to 24/192 sourced files, we see very similar performance at 1 kHz as we did with 24/96 files. The noise floor remains around the same level, as does the dynamic range. The one thing we can see is a peak way out at 65 kHz, though that appears in every 24/192 test so it could be background line noise that is showing up at this resolution, or an artifact from the Meridian, but again it is so low and outside the audible range that I don't worry about it.
With the 10 kHz tone at 24-192 we see data almost identical to at 24-96, with even order harmonics being lower than odd order, though the noise floor is a bit higher than with 24/96 test tones.
The 60-7000 IMD test continues to perform very well, with that 14 kHz bump almost hidden away again. The IMD level is incredibly low, just like it was with prior IMD tests.
The 19000-20000 IMD test again has a B-A peak at around 95 dB below the primary tones, and sidepeaks at 80 dB below them.
Overall the Explorer does well on all of the bench tests, 24/96, 24/192, and CD Audio. The noise floor is clearly better with the higher resolution content, and not at the expense of any of the other bench test measurements that I could see. A very fine DAC for playing back all your high resolution audio files.