This applies to the VRM Box

During development, the VRM Box was tested on a wide variety of headphones of different designs (e.g. open and closed) and of varying cost and quality. To test the VRM Box, we used:

• Sennheiser HD 280
• Sennheiser HD 650
• Beyerdynamic DT 100
• Beyerdynamic 770
• Beyerdynamic PROline 650

The better the headphones frequency response, the more the individual speaker's qualities will be discernible. However, the VRM system was not designed with one specific model of headphones in mind.

When considering headphone impedance, the general principle is that higher impedance headphones typically have a flatter frequency response, however, they require more power from the headphone amplifier to provide the same output level as headphones with a lower impedance.

The VRM Box's headphone amplifier should be powerful enough to drive higher impedance headphones at a high enough level for most purposes.