Playing high-definition audio on a standard player is a bit like playing a state-of-the-art 1950s vinyl stereophonic record on a wind up Victrola – you can do it, but it just won't be the same as on the Hi-Fi. In an effort to create a portable player that does justice to hi-def digital playback and streaming, Pioneer came up with its XDP-100R. We recently got our hands on one, slapped on the headphones, and cranked some tunes to see what it could do.

One of the big buzzes in audiophile circles in recent years has been the advent of high-definition digital audio. Using massive audio files in uncompressed formats that are designed to pick up every nuance of a performance thanks to high sample rates and bit depth, they've been hailed as both the next step in listening enjoyment and as a pointless technological dead end.

Some people claim that it isn't possible to tell the difference between high-definition files and conventional ones. Others say that the difference is obvious and the equipment needs to address this. Still others say it doesn't matter because the players are too expensive compared to just using a smartphone. However, this is a question that has stalked audio debates ever since the invention of High-Fidelity. As to price, devices like the Pioneer XDP-100R-S (which retails for US$700) may be a bit steep for the average consumer, but for the dedicated audiophile shelling thousands of dollars for a turntable, it's practically the deal of the century.

The first thing we noticed about the Pioneer XDP-100R-S out of the box was that it looked like an armored smartphone. The 4.7-in, 1280 x 720 touchscreen is conventional enough, as is the white/silver color scheme for the 100R-S and the black for the 100R-K, but this is set in a machined aluminum case that increases the dimensions to 5 x 3 x 0.5 in (127 x 76 x 13 mm) and the heft to 0.4 lb (181 g). In addition, there are removable plastic bumpers on the top and bottom to protect the jacks and mic/speaker.

Inside the 100R is a Qualcomm APZ8074 processor with a 2.2 gHz Krait 400 quad-core processor and 450 MHz Adreno 330 GPU running Android OS 5.1.1. It comes with 32 GB of internal storage, but the two SD ports allow this to be expanded to up to 432 GB. Taking a cue from larger music players, the 100R divides the Digital-to-Analog Converter (DAC)/9601K AMP circuit board and CPU circuit board to keep noise and jitters down. According to Pioneer, the DAC/AMP board has its own capacitors and a closed-loop design for cleaner audio.

Connectivity for the 100R is courtesy of Wi-Fi and Bluetooth, and there's a Micro USB port for charging and direct link to a computer or as an audio output. In addition, there's a built-in speaker/microphone and a 3.5-mm stereo audio jack.

Since this is a high-end audio player, Pioneer naturally puts a great deal of emphasis on the sound technology. User control is extremely granular, with a selection of 16,000 discrete bands and the ability to save up to 1,000 EQ profiles. There is a seven-position Lock Range Adjust feature to control signal to noise ratios and eliminate jitters during digital-to-audio conversion, as well as a choice of digital filters.

According to Pioneer, the 100R has Master Quality Authenticated playback support with firmware updates and Direct Stream Digital, which has a high-resolution playback rate of up to 192 kHz/24-bit 32-bit Integer/float 24-bit down convert with the 3.5-mm jack, or up to 384kHz/24-bit 32-bit Integer/float 24-bit down convert with the Micro USB jack.

Out of the box, the setup of the 100R was about as simple as any high-end mobile device. Of course, though it's the size of a smartphone, it's actually more of a small, specialized tablet without any phone functionality. Setup was simply a matter of charging the unit, then hitting the power button. The player comes with a number of apps already installed, including a proprietary audio player, though Pioneer was keen to point out that the one included with the review unit was very much a beta version and not to be taken for the one available to consumers.

Our first impression in using the 100R was one of disappointment. We found it cranky and very unwilling to carry out many functions, but we soon discovered that, like many smartphones, the first thing it does on initial setup is to download and install a raft of updates. This meant a couple of hours of patience on our part as the 100R sorted itself out.

On the upside, the wait did give us a chance to look at the mechanics of the 100R. The machined aluminum case has a refreshingly heavy feel to it and the side controls for power, play, and track selection were easy to operate by touch. On the opposite side is a thumb-wheel volume control that, while easy to use, could have done with more tactile feedback. Meanwhile, the bumpers were a mixed bag. While the bottom one gives good protection to the large speaker, the top, handle-like one seems to be largely aesthetic in function.

Once we got it up and running, we found that in the realm of sound, the 100R definitely delivers. Of course, the caveat is that the player by itself only does half the job. The built-in speaker is really just a way of verifying that the unit is working. To get the most out of the 100R, you need high-end speakers or headphones. Using ordinary output devices negates any positives and you're wasting your money.

In testing the 100R, we used not only high-resolution files, but also conventional MP3s (some of which were duplicates of the high-resolution versions), and a tone generator app. We also compared the 100R to the performance of a smartphone app and desktop computer player.

We found that in playing hi-res files, the 100R produced a remarkably rich sound. The reproduction was exceptional in the full range from very low bass to high treble as well as in the mid range. Clarity was strong with little or no jittering or distortion. It was particularly good in acoustic or string pieces, where it was possible to pick out individual instruments and fine nuances of string work. When used with pure tones, reproduction was clear except at the very highest and lowest threshold levels, which produced some distortion and fade out.

Even in very familiar pop music pieces there were surprises, with Beatles tunes revealing previously unnoticed characteristics, editing artifacts, and what sounded like a chair scrape in the studio. The difference between the hi-res and MP3s was often very obvious, though the latter showed a marked improvement over more conventional players.

The difficulty in evaluating high-end players is that not only does the player itself influence quality, but so does the file and the speaker or headphones used, which is why we used the computer and smartphone. In our admittedly unscientific testing, the combination of the 100R, high-end headphones, and hi-res files consistently produced the best results.

One interesting point is that with hi-res and conventional files of the same tune on different players, we found that there was a higher probability of picking the hi-res file on the 100R over a conventional player. However, this probability dropped drastically on some overproduced studio songs that had been edited, sound-boarded, synthed, and autotuned to death, which goes to show that a high-resolution bologna sandwich with American cheese on white bread is still pretty much the same as the standard version.

In addition to the preinstalled house app, the 100R can run any number of other apps and streaming services, such as YouTube, Spotify, Amazon Music, Pandora and others, as well as games and other apps, so it's as much an entertainment system as a music player. In addition, we found the microphone to be of very good quality and when we used the 100R for conducting interviews the clarity of playback was very good.

All this being said, the 100R has some noticeable limitations. For example, Pioneer says that the 100R can manage 16 hrs of playback, though we found this to be much less when the screen is active, with it dropping to 15 percent power in about three hours. Also, the touchscreen interface is a bit too sensitive, which can result in being thrown into unintended apps and getting lost or ending up with a train of apps all unknowingly running at the same time.

But the biggest drawback is in the 100R's strength. It can handle a lot of bandwidth, which allows it to play massive files in real time with high quality. Unfortunately, it also makes it very sensitive in bottleneck areas. This is a player that likes to be left alone. Fiddling with it while playing hi-res files causes it to skip, as does hooking it up to networked wireless speakers. In addition, the Bluetooth connection is very sensitive and the speakers or headphones had to be kept within 12 ft (4 m) of the player. Wi-Fi was as bad, with router connections lost entirely if the player was more than 20 ft (6 m) away or had a wall in between.

In all, we found the Pioneer XDP-100R-S to be an impressive bit of technology with limitations that make this a player more for keeping on one's person than sticking on a shelf while walking about with headphones. Its advantages as a player don't warrant the expense for the average consumer, but for audiophiles who want a portable player that can deliver the full sound spectrum, the 100R is worth a look despite its limitations.

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