The OPPO PM-1 and OPPO PM-2 share the same primary physical components (including the driver, aluminum frame, removable earpad and cable design, and rotating earcups) but there are a number of changes with regard to the materials used in the construction of the two headphones, as well as with the accessories that each pair of headphones comes with.

The chart below provides a comparison between the two headphones:

Using his extensive experience and expertise with human ears' acoustic characteristics, our acoustic designer tuned the PM-1 to sound like a live performance or high-end speaker system listened to at an optimal distance. When paired with the original lambskin leather or velour earpads, the result is a headphone that is very easy to listen to and works well with all music genres and playback devices.

Following the release of the PM-1, customers provided valuable feedback and expressed interest in increasing the treble response. Our acoustic designer responded with an alternative earpad design featuring slightly elevated treble response while maintaining excellent bass and midrange performance. This alternative design is also applied to the PM-2's earpads.

Since both headphones utilize the same driver and follow the same acoustic design principles, the PM-2's performance and sound signature are very close to the PM-1, especially when the PM-1 is paired with the alternative earpads. PM-2 owners wanting to experience the PM-1's original sound can purchase the PM-1's original lambskin earpads separately.

"Break in" is a process of accelerated aging for mechanical, electronic, and acoustic components. By exercising the components for a period of time, early component failures can be weeded out and parts can settle down to their final working mode. With advances in manufacturing processes and quality control, break in is no longer universally prescribed. Many manufacturers, including OPPO Digital, recommend that customers use the products normally and maintain that the products will achieve optimal performance either out of the box or after a very short period of use.

For customers who want to take their headphones through a break in process, please be mindful of the overall volume level when breaking in the headphones; similar to the way in which a speaker can be overdriven, damage can also occur to headphone drivers when subjected to excessive volume levels. One of the features of the OPPO Planar Magnetic Headphones is its high sensitivity, measured at 102 dB / 1 mW. This means that it requires relatively little power to drive the PM-1 to comfortable listening levels. This also means that if you connect the headphones to a powerful headphone amplifier, such as the OPPO HA-1, you can damage the headphones by setting the headphone amplifier to its highest volume level (in particular, when using the balanced XLR connection in conjunction with the High Gain mode at full volume). The volume level produced by this combination would be painful to listen to, and it would also very likely damage the headphones. In short, you do not want the break in process to actually break the headphones.

Ultimately, we recommend just listening to your music - don't worry about break in; after about 24 hours of listening time, you will have a very clear idea as to how the headphones will sound. But if you insist on a prolonged break in period, please make sure you are using volume levels that you would normally listen to music at. We do not recommend breaking in the headphones using pink noise, white noise, or sine waves, since these methods exercise the diaphragm in a way that is very different from normal music, and it is very easy to choose a potentially damaging volume level when using these signals.

No matter what pair of ear pads you decide to use with the PM-1, the sound signature will remain very similar overall. However, there are still a number of differences in sound quality that each ear pad type brings to the table.

Frequency response measurements of each ear pad type are available at headphone review websites such as Inner Fidelity, and we have also provided brief descriptions of the type of sound you can expect to hear with each ear pad type below.

Original Lambskin Leather Ear Pads

These ear pads ship with the PM-1 and feature a very smooth, non-fatiguing, and intimate sound with seductive midrange that works well with any type of music. The sound signature is a bit warm overall.

Structurally, there is a felt ring in the circular rear opening of the ear pad, and both the inner and outer walls of the ear pads are perforated.

Velour Ear Pads

These ear pads ship with the PM-1 and have a slight increase in both sub-bass and treble response versus the original lambskin leather ear pads and are still very close and intimate sounding with the same excellent midrange. The sound signature is a bit warmer than the original lambskin leather ear pads, and they can be described as providing a "tube-like" sound. They are also incredibly comfortable.

Structurally, there is a felt ring in the circular rear opening of the ear pad.

Alternative Lambskin Leather Ear Pads

These ear pads ship with the PM-1 and have more linear bass and treble response versus the original lambskin leather and velour ear pads while maintaining very similar midrange performance. Bass extension is slightly greater than either of the other two ear pads, though bass impact is slightly lessened compared to the velour ear pads. These ear pads can also be considered a bit more open sounding than the other two ear pads.

Structurally, there is not a felt ring in the circular rear opening of the ear pad, and there is a segment of the inner ear pad wall that is not perforated.

Synthetic Leather Ear Pads

These ear pads ship with the PM-2 and are sonically equivalent to the alternative lambskin leather ear pads, though they are made of synthetic leather.

Structurally, there is not a felt ring in the circular rear opening of the ear pad, and there is a segment of the inner ear pad wall that is not perforated.

"Break in" is a process of accelerated aging for mechanical, electronic, and acoustic components. By exercising the components for a period of time, early component failures can be weeded out and parts can settle down to their final working mode. With advances in manufacturing processes and quality control, break in is no longer universally prescribed. Many manufacturers, including OPPO Digital, recommend that customers use the products normally and maintain that the products will achieve optimal performance either out of the box or after a very short period of use.

For customers who want to take their headphones through a break in process, please be mindful of the overall volume level when breaking in the headphones; similar to the way in which a speaker can be overdriven, damage can also occur to headphone drivers when subjected to excessive volume levels. One of the features of the OPPO Planar Magnetic Headphones is its high sensitivity, measured at 102 dB / 1 mW. This means that it requires relatively little power to drive the PM-1 to comfortable listening levels. This also means that if you connect the headphones to a powerful headphone amplifier, such as the OPPO HA-1, you can damage the headphones by setting the headphone amplifier to its highest volume level (in particular, when using the balanced XLR connection in conjunction with the High Gain mode at full volume). The volume level produced by this combination would be painful to listen to, and it would also very likely damage the headphones. In short, you do not want the break in process to actually break the headphones.

Ultimately, we recommend just listening to your music - don't worry about break in; after about 24 hours of listening time, you will have a very clear idea as to how the headphones will sound. But if you insist on a prolonged break in period, please make sure you are using volume levels that you would normally listen to music at. We do not recommend breaking in the headphones using pink noise, white noise, or sine waves, since these methods exercise the diaphragm in a way that is very different from normal music, and it is very easy to choose a potentially damaging volume level when using these signals.