Within the DP-X1’s settings you have many options for general operations. In the music settings you can choose which form of amplification you wish to use (ACG or BT) as well as eq. The DP-X1’s eq functions include five presets as well as 16-band user-selectable ones. Adjusting the 16-band eq requires a steady finger (or stylus) since the delineations are rather close together. The Onkyo also has something called “featured eq” which includes 18 different settings developed for different pop musicians including Buckcherry, Scott Ian, Tim Lopez, Steven MacMorran, Midi Matilda, Leo Nonventelli, Strange Talk, Chris Traynor, and Jim Ward. You can modify any of these eq settings and store up to 1000 custom eq curves.
The DP-X1 has three gain levels. But the differences between level settings aren’t so great that you can’t use “low” with low-sensitivity headphones. I know this because for the first couple of days I used the default “medium” with a wide variety of headphones before I found the gain adjustments, which are buried among the Sound & Notification settings. Perhaps seasoned Android users will find these nested menus old hat, but for new Android users the Onkyo’s menu system will require a learning curve. The onboard owner’s manual app is essential reading if you hope to become deft at navigating through the DP-X1’s many features. Some adjustments, such as upsampling, digital filter, and DSD upsampling-conversion options, are found within the Onkyo music player app via a drop-down menu. While its settings are not as convoluted as those of some players, the DP-X1’s more arcane controls are not intuitive in function or location.
The DP-X1 supports Bluetooth headphones or other playback devices via aptX. Once paired you can send an audio stream to any compatible BT device.
Battery life is listed at 16 hours using 96/24 FLAC files and a single-ended headphone connection. With balanced headphones, battery life will be quite a bit shorter. Also, if you leave the DP-X1 hooked up to a balanced headphone in pause mode overnight, the battery will be exhausted by morning and need a full recharge, which takes somewhere around three hours.
Populating the DP-X1 with music was as simple as connecting it to my MacPro’s USB 3.0 inputs. Onkyo has its own file-transfer app called X-DAP Link (PC and Mac), which you can download from its site, but I used another app called Android File Transfer to move files into the DP-X1. This little app popped up every time I connected the DP-X1 to my Mac via the supplied USB cable. One further advantage of this method was that instead of appearing on my desktop as an external drive, which is what occurs with many portable players, the DP-X1 is recognized by the app, but not as a drive so you don’t have to wait for it to un-mount before disconnecting it.
The DP-X1 can also be used as a “source device” to connect to other USB DACs. You will need a special cable to accomplish this, but Cables to Go, among other sites, has what you need to make the connection. Once hooked up you have a multitude of options to send files to an external DAC, including upsampling and different DoP (DSD over PCM) file protocols. And if your external DAC is MQA-compatible, the DP-X1 can even output MQA files to that device.
I’ve reviewed a fair number of portable players during the past couple of years. With most of them the primary limiting factor in overall fidelity has not been the player itself, but its synergy with the headphones or transducers connected to it. I used a plethora of headphones with the DP-X1 from hyper-efficient in-ears like the Westone W60 to the most power-hungry full-sized cans, such as the Beyerdynamic DT-990 600-ohm version. Even in single-ended mode the DP-X1 had no trouble driving the DT-990s to satisfying levels, and with the efficient ones the low-gain modes delivered sound without hiss or hum.
I used the DP-X1 via its single-ended output for several weeks before I received a Silver Dragon adapter cable to go from the 2.5 TRRS connection to a standard 4-connector XLR from Moon Audio. With the adapter installed I tried all the headphones in my collection that use balanced connections. These included the HiFIMan HE-560, Sennheiser HD700, Grado RS-1, Audeze LCD-2.2, AudioQuest Nighthawk, and Mr. Speakers Ether and Ether C. I also tried both of the DP-X1’s balanced modes, Bal and AGC. I found the Bal had a slightly higher output level. With several phones, including the Mr. Speakers Ether-C, I preferred Bal overall due to its superior dynamic contrast and bass extension.