Media Streamer

Marantz NA7004 Network Music Streamer

ARTICLE INDEX

On the Bench

The bench tests for the NA7004 were done with our standard set of CD quality, 16 bit, 44.1 kHz test tones converted to various formats including FLAC, ALAC (Apple Lossless Audio Codec), WMA 9.2 Lossless, WMA 9.2 and MP3 at 128 kbps. The tests were done using SpectraPLUS software measuring the analog output of the NA7004.

At 1 kHz, THD+N for CD (FLAC encoding) played from a USB stick connected to the front iPod/USB input was 0.00108%.

At 1 kHz, THD+N for CD (FLAC encoding) streamed via DLNA using the Asset UPnP server was 0.00110%.

At 1 kHz, THD+N for CD (ALAC encoding) played from an iPhone connected to the front iPod/USB input was 0.00113%.

Here’s the exact same test with the M-DAX filter set to “Low”. At 1 kHz, THD+N for CD (ALAC encoding) played from an iPhone connected to the front iPod/USB input was now 0.00292%. We also have a harmonic at 2 kHz and the peak at 3 kHz is now slightly higher.

At 1 kHz, THD+N for CD (ALAC encoding) streamed from an iPhone via AirPlay was 0.07823%. I was very surprised that the results were not similar to my findings when playing the ALAC encoded file from the iPhone via the iPod/USB input. The AirPlay results fluctuated during my bench tests. The average results are what you see below.

Here is a quick snapshot of a couple random samples taken from the same AirPlay test. Note the significant difference in THD+N which is now just 0.00126%. The noise floor is also where it belongs. These results were consistent across all the tests involving AirPlay. I reported the AirPlay bench results to Marantz and will let you know if I get a response to the issue. Despite the bench results, listening to music encoded with ALAC streamed via AirPlay sounded great.

At 1 kHz, THD+N for CD (ALAC encoding) streamed from iTunes via AirPlay was 0.03156%.

At 1 kHz, THD+N for CD (WMA 9.2 Lossless encoding) played from the Windows Media Player from a Windows 7 laptop via the rear USB input on the NA7004 was 0.00196%.

At 1 kHz, THD+N for CD (WMA 9.2 encoding) played from a USB stick connected to the front iPod/USB input was 0.19855%. This result should put to rest any notions of using the WMA 9.2 lossy format.

At 1 kHz, THD+N for CD (MP3 128 kbps encoding) played from a USB stick connected to the front iPod/USB input was 0.00275%. While I wouldn’t listen to it for critical listening, I was really impressed with how well the typical MP3 encoding performed on this test compared to the previous WMA 9.2 lossy results.

Here are the results for 19 kHz, 20 kHz combined test frequencies for CD (FLAC encoding) played from a USB stick connected to the front iPod/USB input. There is no visible B-A peak at 1 kHz.

Here are the results for 19 kHz, 20 kHz combined test frequencies for CD (FLAC encoding) streamed via DLNA using the Asset UPnP server. There is again no visible B-A peak at 1 kHz.

Here are the results for 19 kHz, 20 kHz combined test frequencies for CD (ALAC encoding) played from an iPhone connected to the front iPod/USB input. There is no visible B-A peak at 1 kHz, but we do see some additional peaks at -100 dBV on either side of the fundamentals.

Here are the results for 19 kHz, 20 kHz combined test frequencies for CD (ALAC encoding) streamed from an iPhone via AirPlay.

Here are the results for 19 kHz, 20 kHz combined test frequencies CD (ALAC encoding) streamed from iTunes via AirPlay.

Here are the results for 19 kHz, 20 kHz combined test frequencies CD (WMA 9.2 Lossless encoding) played from the Windows Media Player from a Windows 7 laptop via the rear USB input on the NA7004. There is no visible B-A peak at 1 kHz.

Here are the results for 19 kHz, 20 kHz combined test frequencies CD (WMA 9.2 encoding) played from a USB stick connected to the front iPod/USB input. There is no visible B-A peak at 1 kHz.

Here’s the exact same test with the M-DAX filter set to “Low”. Notice that the filter is having a hard time understanding what to do with the test signal and is adding a lot of noise to the output.

In case you were wondering, there is no graph for the 19 kHz, 20 kHz combined test frequencies with MP3 128 kbps encoding since those high frequency signals are discarded by the MP3 encoder.

The IMD measurement for CD (FLAC encoding) played from a USB stick connected to the front iPod/USB input was 0.0006% which was excellent.

The IMD measurement for CD (FLAC encoding) streamed via DLNA using the Asset UPnP server was 0.0010%.

The IMD measurement for CD (ALAC encoding) played from an iPhone connected to the front iPod/USB input was 0.0006%.

The IMD measurement for CD (ALAC encoding) streamed from an iPhone via AirPlay was 0.2280%.

The IMD measurement for CD (ALAC encoding) streamed from iTunes via AirPlay was 0.0915%.

The IMD measurement for CD (WMA 9.2 Lossless encoding) played from the Windows Media Player from a Windows 7 laptop via the rear USB input on the NA7004 was 0.0011%.

The IMD measurement for CD (WMA 9.2 encoding) played from a USB stick connected to the front iPod/USB input was 0.0875%.

The IMD measurement for CD (MP3 128 kbps encoding) played from a USB stick connected to the front iPod/USB input was 0.0012%.

Based on these results, I would rank the file format performance on the NA7004 from best to worst in this order: FLAC, WMA 9.2 Lossless, ALAC via USB, MP3, ALAC via AirPlay, and finally WMA 9.2.