Emily Palen - The Inevitability of Water (from the CD 'Glass')
This is a very unusual recording of violin improvisations, recorded fairly close-up but with plenty of space around the instrument. This is not only interesting music (judged by someone who does not have any other solo violin recordings), but it's a sonic masterpiece I think, suitable for critical audio comparisons.
Reviewed using new white ATH M50 headphone with:
1. Netbook PC using HRT HeadStreamer DAC-plus-headphone-amp. The netbook PC was running on its fully charged battery (not connected to the charger). The HeadStreamer was connected to the PC using the HRT-supplied 20 inch USB cable.
2. iPhone4s using iStreamer DAC plus Objective2 headphone amp. The iPhone was fully charged, the O2 amp was fully charged and running on battery only, and the iStreamer was powered by the Mophie 5v 2.1 amp battery pack. The iPhone was connected to the iStreamer using a 4 inch 'InCase' cable (see below) and the iStreamer to the O2 amp using a 14 inch 'Straight Wire' audiophile cable.
First test used 96 khz FLAC track on the PC and 320k CBR MP3 on iPhone. Since the iPhone4s does not support FLAC, and enabling FLAC brings other software and space limitation issues into the picture, I decided against that (see below).
Second test used the same MP3 (converted by latest version Foobar2000) on both the PC and the iPhone - PC using Foobar2000 and iPhone using the default iPhone music player.
In the first test the HeadStreamer won handily. The iPhone/iStreamer sounded dull and closed in by comparison. The second test was closer, but the PC HeadStreamer still won with an obvious edge in openness and sense of air around the violin. I tried iStreamer's supplied 20 inch Apple cable but it was no better than the 4 inch InCase cable. Since that particular cable carries only the unprocessed digital signal, I wouldn't expect a significant sonic difference unless the cable were very long or otherwise incapable of carrying the digital data properly.
Since the HeadStreamer beat the iStreamer MP3-to-MP3, I would expect a similar result with FLAC tracks on both the PC and iPhone, unless something could be changed that I'm not aware of. A better amp could be used in place of the O2, but already the iStreamer plus assembled O2 is $340 USD versus $140 for the HeadStreamer. One other possibility that seems remote would be powering the iStreamer using a better battery such as the KingRex Upower, but that adds another $100 to the already $200 difference.