PMC EB1i Transmission Line Loudspeaker

I had more difficulty than usual finding the right places to put the EB1is in my room and wondered whether their much-vaunted wide dispersion might not be a problem. Pete says the reason for having it is image placement, but there is a delicate balance between that and the nasty effects of early reflections from the room. “In the recording environment you record 180 degrees of whatever is making the sound, you’re recording this side of the instrument or voice, so to reproduce that in the recording studio you need a speaker that can reproduce that radiation pattern. If you can get a reasonably flat response up to about ±60 degrees then you can reproduce a recording pretty accurately. The reason why speakers sound different is not the on axis response because they’re nearly all reasonably flat, it’s the off axis response that is crucial. Because if the off axis response isn’t flat then the reflection from the wall won’t be flat either. I will make the on axis response slightly worse in favour of the off axis and will measure from -60 to +60 degrees around the axis and go for a balanced response.

“If you listen to directional versus wide dispersion speakers the latter will present a much deeper, wider, higher image which is our goal.” Given the size of the EB1i I was surprised that it doesn’t have higher sensitivity than its specified 89dB at 4 ohms: “We sacrifice sensitivity to the drivers and to the fourth order crossover in order to achieve a more neutral result. I can’t say that sensitivity is such a high priority because people who buy speakers like this tend to be able to afford powerful amplifiers. With the smaller models we go for the maximum sensitivity that can be achieved.”

Installing the EB1i in place of the more expensive B&W 802D brought about a fairly big change in balance. Essentially the midrange seemed more prominent, a factor that had a dramatic effect on albums like Gillian Welch’s Time The Revelator. This recording has often hinted at a slight edginess but in the PMC’s hands became almost uncomfortable due to that exposure through the midband. Conversely material that had seemed a little dense or thick in the past opens up to reveal a wealth of detail and space, Fink’s Biscuits For Breakfast being a prime example. The title track was transformed into a far more revealing piece and his take on ‘All Cried Out’ seems far more cutting and powerful.

The EB1i sounds more efficient than the specs suggest, which is probably because of the TL factor, the bass is seemingly more open and easy than usual, almost as if it doesn’t require as much effort on the amplifier’s behalf. As the power amp being used was a Classé CA-2200, reserves in the amperage department were unlikely to have been stretched anyhow, but it’s an interesting and appealing effect.

This low frequency ease reveals a lot of the stuff you aren’t supposed to hear, like people knocking a mic stand or tapping feet on a board floor. Of course it also makes full use of the sound that the mic is supposed to be capturing; the full-bodied timbre of a double bass and the heavy chug of dub are both delivered in convincing and unforced fashion. I particularly enjoyed Tosca’s marvellously named Chocolate Elvis with its heavy manipulating of the nether notes. But whilst this is the sort of speaker that has you digging out discs that have “great bass” on other speakers, it can sometimes reveal that what had previously worked so well may well have been a result of bass distortion rather than the recording. With bass that’s as clean as the EB1i offers, you are getting a lot closer to the truth than most passive systems can reveal.

It also images well, John Surman’s saxophone on the album Thimar seemingly disconnected from the cabinets altogether. These speakers are remarkably good at getting out of the way and letting the character of the music take the lead. Thus Barb Jungr’s rendition of ‘Who Do You Love?’ is vibrant and crisp, with lovely tone from double bass, acoustic guitar and voice alike.

The new tweeter makes itself heard when you play some trumpet, like Avanim’s Third World Love. This has tremendous immediacy and spatial resolution. What’s more there’s none of the usual break up that trumpets seem to induce in tweeter domes. Rather late in the day I realised that I was using a DNM interconnect on the Resolution Audio Opus 21 rather than my preferred Living Voice cable; switching them over both beefed up the bass and calmed the mid and was far better suited to the job (note to self: use the right wire for the job!). I could now turn it up more without the room joining in and continued playing as many favourite albums as I could lay my hands on. Rather a pleasant experience as you might imagine and one that I could happily carry on with if it weren’t for these darn deadlines. Another late revelation was that despite its size and bandwidth the EB1i needs a little bit of rear wall reinforcement to produce the best results. Most of my listening was done with them at the more open end of the room where the floor is more solid and the wall two or more metres back, but switching things around so that the wall was only a metre behind the front baffle seemed to work better. Cuts with excessive bass sounded excessively bassy, but most sounded better balanced. The Fink album in particular turning into a rather better recording than had previously been apparent. The low distortion is still the hallmark that allows you to hear so much fine detail and space from every record that is spun, but with this set up I found it was possible to listen at higher levels without discomfort – despite the presence of closer side-walls. The EB1i is a more open and sophisticated loudspeaker than its predecessor. The changes to tweeter, crossover and cabinet have brought about a reduction in distortion across the board that makes for a highly revealing and damned enjoyable loudspeaker. Now, what excuse can I find to hold onto them for a few months?