But, in my opinion, when it comes to headphones, much more annoying than a somewhat weak amp is an unnatural sounding stereo image. SPL tackles this phenomenon with the so-called Phonitor Matrix. The reasoning behind this circuit is that the listener perceives low frequencies less intensively when using speakers than when the drivers of the headphones output sound directly into the listener's ears. This is due to the angle between the speakers and the reflections of the right signal on the left side of the room ─ or the acoustic crosstalk between speakers ─, for instance. The Crossfeed control allows you to recreate the influence of different rooms on the frequency response, dependent on the volume. So, when the Matrix switch is set to "Cr/A" or "All," for example, less low frequency energy is sent to the headphones than when in linear mode, i.e. without any corrections. While the Crossfeed switch affects primarily the frequency range, the Speaker Angle parameter affects the interaural time differences of a signal on both channels. According to SPL's CEO, Hermann Gier, the combination of both parameters allows you to emulate an experience that is very similar to listening to a pair of loudspeakers in your home listening room. You nevertheless need to subtly reduce the phantom center image with the Center control, otherwise it may appear too loud due to the corrections applied with the other two parameters. While the first Phonitor required you to engage two switches to compare the original signal with the one affected by the device's parameters, in the Phonitor 2 you only need the Matrix switch. This new version has become a tad more user-friendly. At this point, I would also like say that the SPL unit offers studio professionals all the possibilities to analyze a stereo signal by ear, thanks to the Phase, Solo and Mono/Stereo buttons.

Let's move on now to the Phonitor 2's second unique feature: As far as I know, there is no other headphone amplifier that uses the 120-Volt technology. This means that the Phonitor's active components are fed with a symmetrical 60-Volt DC voltage. Higher supply voltages guarantee a higher headroom and less distortion, provided the subsequent circuit can actually use this extra energy, obviously. However, there are no integrated components that can handle this voltage. That's why SPL developed the SUPRA discrete operational amplifiers some time ago. But by no means have they slept on their laurels, SPL is continuously improving the op-amps. Hence, the Phonitor 2 features even smaller and more efficient op-amps than its predecessor.