digiZoid ZO2 Installation and Use
There are two ways to install the ZO2 Personal (not a) Subwoofer. You can use the 3.5mm jumper cable from your source to the ZO2 or you can use some sort of line out cable that terminates into a 3.5mm jack. In the latter case, you'll have to provide your own cable as digiZoid only provides the 3.5mm jumper. This seems reasonable considering the multitude of uses a consumer might have for the ZO2.
While the obvious use is between your headphones and your phone or portable music player, there are tons of other applications. If you connect your phone to your car stereo via a 3.5mm cable, you can easily integrate the ZO2. Between your computer and headphones or desktop speakers? No problem. With the size of the ZO2, the problem is not going to be portability (other than possibly losing the thing) as it goes everywhere. Plus, it is so light you can leave it dangling on the cable and not have to worry about any damage to your ports.
Once you've installed it, you need to press the button to turn it on. It will default the first time to the typical bass boost in headphone mode. This is signified with a yellow light on the front. Pressing the button again will sent it into mode select. As it defaults in Headphone mode, the front will glow pink. Press the button down (roll it toward the bottom of the ZO2) and you'll switch to a blue/purple color. This is Line mode where you have volume control. Up and down on the button will control your volume. To switch back into Headphone mode, hold the scroll button up for about 10 seconds until the light turns pink again.
When in mode select, a single button press will send you back to the bass boost selection mode. Here you have 32 degrees of bass boost from nothing (flat) which will show green to maximum bass boost which will glow red. The levels of bass boost vary and become less dramatic as you go up (meaning at first you get a big difference between the amount of boost with each level while at the top a level up represents much less boost). You can press the button for each level or hold it down to scroll through the levels faster. One long press turns the ZO2 off and a single press turns it back on. After you adjust the settings on the ZO2, it stores those settings.
For this review I used the ZO2 with a number of different headphones. I have a large number at my disposal with price points between $40 and $300. For the most part the headphones used were the Arctic P402 ($40), the Moshi Vortex Pro ($150), and the Pioneer SE-MJ591 ($300). Each of these headphones have a different sonic signature with completely different "problems" that may or may not be made better or worse by the inclusion of the digiZoid ZO2 Personal (not a) Subwoofer.
Before I go on, I believe I may lose some of you after this paragraph. Just remember that the ZO2 has more uses than with your phone. If you have headphones with in-line controls or an in-line mic, the ZO2 renders them inoperable. It does not, for whatever reason, pass the signals back to the phone needed for control and voice. It also doesn't fool your phone into thinking that those controls and mic are operational so you end up being able to use the phone just as you would if you were wearing headphones without in-line controls and mic. An annoyance? For sure. And maybe a deal-breaker for some. But the ZO2 still has many uses that may outweigh this downside.
Charging the ZO2 took very little time and the run time is so long that I didn't think to charge the thing for days at a time. There is a secondary red light at the bottom of the light bar on the front that will blink when your battery gets low but that rarely happened to me even after days without a charge (and I was using the ZO2 nearly constantly). Charging the ZO2 while in use adds no audible noise to playback (unlike charging and using my phone at the same time) unless your source and the charging connection are the same (charging the ZO2 with the same computer that is providing the musical output).
While the ZO2 is very light and portable, I did wish there was some way of securing it to your phone. While it wasn't too much of a hassle to stick it in your pocket with your phone, I wanted a way to connect it to the back of my phone case. In what was probably a fit of madness, I attached a piece of Velcro to the back of my Samsung Galaxy Nexus Otterbox Commuter case and to the back of the ZO2. This created the perfect way to store the ZO2 when I was out and about and the ZO2 was thin enough that I could still stick the phone with the ZO2 attached in my back pocket. Since then, I've racked my brain for a solution that digiZoid could include with the ZO2 but I've come up empty. The Velcro works well but the connection is so strong that you have to be careful removing the ZO2 as you can feel the case flex if you put too much pressure on it.
So I can get this one for a whole lot less and use my EQ settings to boost the bass:
FiiO E11 Headphone Amplifier 230-106 [parts-express.com]