Logitech’s new Ultimate Ears Personal Reference Monitors (PRM, $1999.99) are the most expensive, luxurious, and great sounding in-ear monitor Playback has tested to date and it’s the first one to provide an answer to the eternal question prospective buyer’s always ask; namely, “Will I like the voicing of this monitor?” With the PRM, the answer to that question will almost invariably be “Yes,” and the reason why is that, unlike any other custom-fit in-ear monitor we know of, the PRM provides both a custom fit and a completely customizable sound that can be shaped to suit the owners’ specific needs, wants, and tastes.
How, then, does the PRM sound? The truest answer would be to say it sounds however the buyer wants it to sound—within reason. (UE gives PRM buyers plenty of latitude in creating response curves for their monitors, but there are some practical limits.). Even so, the PRM is the only in-ear monitor that lets each owner custom shape the response curve of the product exactly as he or she sees fit. Indeed, if users need or want to do so, they can even specify separate voicing curves for their left and right ears. No other monitor gives users greater flexibility in terms of shaping precisely the sound they want to hear. That freedom is a big part of what you pay for when you invest in a set of PRMs.
How does Ultimate Ears manage the PRM customization process? Everything begins when a customer approaches UE and is assigned a trained “personal service specialist” who will walk the customer through the process from start to finish. The first step involves the customer spending time at what UE calls a “Personal Reference Tuning Station.” At the station, the customer will listen through a special test-version of the PRM that has been set up for use with universal-fit-type ear tips (a wide range of tips is provided to ensure a good fit). The test PRM, in turn, is plugged into a Personal Reference Tuning Box that provides inputs for the listener’s source component(s) of choice, an output for the test PRM, and two banks of tuning (or voicing) control knobs. One bank of knobs controls voicing settings for the left channel and the other bank controls settings for the right channel.
There are three tuning control knobs per channel—one to control highs, one to control mids, and one to control bass—with precise numerical markings to show what settings have been dialed in for each knob. The settings range from “0”, which denotes maximum emphasis for the given frequency band, to “100”, which denotes minimum emphasis for the frequency band; when settings of “50”are dialed-in for all tuning controls, the PRM will product the most measurably flat (that is, or neutral) frequency response of which it is capable. However, UE is quick to point out that different listeners perceive neutral frequency response in very different ways, so that the “50/50/50” settings are not necessarily “right,” but rather provide a fixed point of reference from which customers can work in creating their own ideal response curves.
Starting out with all knobs in their “50/50/50” positions, customers are invited to play whatever musical material they wish for as long as they wish, while experimenting with different knob settings as they pursue their ideal sound (UE recommends that listeners do this with their eyes closed, so that they aren’t unduly influenced by the numbers on the control knobs). Quite wisely, I think, UE advises listeners to sample a variety of musical materials they know and enjoy and further advises listeners to evaluate a minimum of five different musical selections before finalizing their preferred tuning settings. As an aid to the listener, UE’s Personal Reference Tuning Box is set up with left and right “Bypass” buttons that temporarily restore settings to the “50/50/50” reference positions, which makes it easier to determine whether one’s personal settings have actually improved the sound or not (from the listener’s point of view). Some listeners complete the tuning process in as little as half an hour, while others take much longer (I took around two hours and went through many different reference recordings when choosing settings for my personal pair of PRMs).
It is important to note that the voicing control knobs are not merely level controls. Instead, the knobs continuously adjust crossover network settings for the PRM, adjusting the relative ratio of output between adjacent frequency bands (for example, the ratio of mids-to-highs or the ratio of lows-to-mids, etc.). In my experience, this meant the control knobs seemed to interact with one another to some degree, so that adjusting the bass knob might also lead to further tweaking of adjustments for the midrange knob, and so forth. If the listener is patient and careful, though, I think the PRM Tuning Box gives users the freedom to dial in virtually any response curve they might want (again, with the option of choosing separate settings for one’s left and right ears). Once the listener is satisfied with his or her tuning choices, the personal service specialist records the settings, and then guides the listener through the next step of the process, which is having ear mold impressions taken. After the ear mold impressions are done, the final step involves customers choosing the custom wood finish they want for the ID plates for their PRMs—a selection the specialist once again records.