When first you sit down at the PRM “define your sound” station, here’s what you’ll see. First, you’ll a UE-labeled, gently wedge-shaped mini-console where you’ll see separate left and right hand banks of three control knobs each, plus connectors for the PRM test monitors and for source components. Most Beta listeners have used an iPod as their source component of choice, although I used an iPod (loaded with lossless and/or WAV files, of course) connected via a very high-quality line out dock (LOD) cable to an extremely high-quality Ray Samuels Audio fully-balanced SR-71B Blackbird portable headphone amp during my listening tests.
The test PRM monitors are built using the normal PRM driver array, but differ from production PRMs in two key respects:
• First, the test PRM is fitted with an extra long sound outlet tube that is shaped to allow used of a wide variety of universal fit-style ear tips (UE keeps an extensive array of ear tips on hand at the PRM station), and
• Second, the test PRM does not use an onboard crossover network as the production PRM does, but rather is wired to use the adjustable crossover components that are built in to the Personal Reference Tuning Station.
UE concedes that this arrangement isn’t precisely like listening to your personal pair of PRMs, in that the production PRMs made for you will offer superior fit and noise isolation and will, of course, be much more comfortable to wear (because they will be shaped to fit you and only you). Nevertheless, the Tuning Station does give you a chance to hear the PRM driver array in action with your music and source components, and with precisely the crossover settings that will be used in your finished pair of PRMs.
Once seated at the station, a UE attendant explains how the control knobs work. The left bank of three knobs controls the left monitor earpiece, while the right bank controls the right earpiece. The upper knob in each bank controls high frequency balance, the middle knob controls midrange balance, and the lower knob controls bass balance. It is helpful to know, though, that these knobs are more than just “level controls,” although they do in part affect perceived level across their respective frequency bands. Indeed, the phrase that UE representatives used was to say that the control knobs affect “the ratio of highs/mids/bass relative to adjacent frequency bands.” In practice, this meant the controls seemed to me to be interactive to some degree, so the adjusting one knob sometimes led to further adjustments for other knobs as well.
As a reference point for the listener, the control knobs are precisely calibrated with built-in numerical readouts where the available range of adjustment runs from 0-100 (where “0” = maximum output/emphasis for the frequency band, and “100” = minimum output or emphasis for the band). When all three knobs are set to “50”, the PRM is delivering what measures as the flattest, most neutral frequency balance possible. However, UE advises that different listeners perceive frequent balance in very different ways, so that it is best to ignore the markings on the knobs and to simply adjust them for what the listener perceives as the most natural, most accurate, or simply the most desirable response characteristics possible.
The good news, here, is that the listener is in charge of the response curve (which is where the freedom part comes in), but the potentially bad news for those of us who lean toward “audio nervosa” is that each PRM buyer must personally take responsibility for creating a response curve that he or she will find satisfying over the long term (gulp!).
UE’s initial plans call for Personal Reference Tuning Stations to be set up at four US locations: New York, NY; Nashville, TN; Los Angeles, CA; and at UE headquarters in Irvine, CA. More US stations may be set up later on, UE also expects to set up PRM stations at strategic locations in Europe and in the Pacific rim.