66 Audio BTS Pro vs Oppo PM-3

The BTS Pro is quite robust and can withstand some minor splashes of sweat or rain as these are sweat-proof. They are not completely water-proof though, so you should not get them soaking wet.

There is good detail in the highs and the mids can also be heard clearly with very little muddiness. The lower frequencies are boosted, resulting in a good level of depth and power to each bass thump.

The BTS Pro ear cups sit on the ears with hooks keeping them in place. The flexible connecting band provides good clamping force and can adjust to your head size with continued use. Combined with cushioning on the cups, these are comfortable to wear and will stay in place.

Bluetooth connectivity allows the BTS Pro to connect with smartphones and compatible music players wirelessly, so cables won't be an issue.

66 Audio's Motion Control iOS App gives users added functionality, including EQ control and presets selection, battery status indicator, and even headphone position tracking. These features can improve the listening experience and also minimize the chances of you losing these headphones.

With up to 40 hours of playback time at full charge, it's more than enough for most listening sessions. You won't have to charge these frequently.

A hard shell carrying case is included, which can protect the headphones from minor impact and also make transport much easier. The case also has good aesthetics.

They are easy to bring on the go as the ear cups can be folded into the headband. This further reduces the already slim and compact size, making them easy to chuck into a bag when on the go.

The right ear cup of the BTS Pro features buttons for controlling headphone features. You can play/pause tracks, increase/decrease volume as well as answer/end calls by pressing the corresponding buttons, negating the need to pull out your phone to do so.

You do not need to take the BTS Pro off in order to answer incoming calls. There is a built-in microphone which allows you to easily take or make calls in the middle of your run or workout.

Treble is quite detailed, but lacks a bit of sparkle on the highest frequencies as they are rolled off. The mids are just right, not too forward and not too rich. The bass has good presence and punch, but is not very powerful.

Its closed back design along with the fairly thick, leather-surfaced earpads are very effective at keeping the music in and the ambient noise out. This is very useful in tracking situations, and will also help you focus on the audio even when in a busy, noisy place.

The headband and ear cups have fairly thick padding to ease the pressure on the head. These are covered with leather material so they feel smooth.

A headphone amp is not required in order for these to pump up good volume and sound details, so these can work well off of portable devices. There is a noticeable improvement in sound quality and volume when used with a proper amp though.

A combination of high quality plastics and metal are used for these so there is minimal flex and rattles. The headphone joints and yoke also have smooth movement, which make these feel premium when held.

The cables can easily be detached, with 3.5mm jacks as ear cup connectors. This makes looking for new/replacement cables very easy.

Stock cable has an in-line microphone. Not only is this convenient for taking calls while listening to music, but the mic's sound quality is good, with voices sounding clear, full and with good volume.