The topic of this review is a quite small but surprisingly heavy two-way speaker from an operation that’s actually based in the Wirral, just across the water from Liverpool. The P-series is a relative newcomer, from a brand that hasn’t been around all that long either.
I first encountered Ophidian some eighteen months ago, and shortly thereafter reviewed its three M-series models Mambo, Mojo, and Minimo, which used six, two, and one 90mm bass/mid drivers respectively. At the time, these three models comprised the entire Ophidian range, all of which used MDF transmission line enclosures to load small US-made drivers. These seemed to perform pretty well, my personal favourite being the middle model of the three, the £999 Mojo.
However, this Prophet P1 is a rather different animal. Superficially it looks altogether more conventional, using a solitary 180mm bass/mid driver with an aluminium alloy cone that crosses over to a 28mm fabric dome tweeter using steep crossover networks that use audiophile grade ingredients. The enclosure is built from plywood and has a vent called AEROFLEX set asymmetrically on the rear, the bass loading actually being a hybrid reflex-transmission line. A key additional feature is a mechanically decoupled front baffle, which is designed to avoid the vibration generated by the drive unit from being transmitted into the enclosure proper. Although that sounds logical enough, it does also mean that the drive units are decoupled from the stands and the environment.
I enquired about the substantial weight, and was informed that this was not at all due to the well-braced plywood enclosure, which is just 12mm thick, but rather was down to the much thicker 25mm front panel, the large ferrite magnets used by both the drive units, and hefty fourth-order crossover network components that include low-loss air-cored inductors with large section wire.
Measurements were certainly interesting, and in most respects rather impressive, as the in-room far-field frequency response is notably smooth and even across the majority of the audio band, holding comfortably within ±2.5dB from 60Hz upwards. However, if that’s the good news, there are a couple of downsides too. The most serious is probably that the sensitivity seems to be significantly below the 88dB that the manufacturer claims. Even my measurement technique, which sometimes seems to be significantly optimistic by about 2dB, can only rate this speaker at around 85-86dB. (The real sensitivity may well be as low as 84dB.) This is modest indeed, indicating that the Prophet P1 will need a reasonably powerful amplifier to drive it, and that valve devices may well be better avoided. However, one advantage that usually accompanies unusually low sensitivity is unusually good bass extension, which is certainly true in this case, as the in-room trace was extended down to around 25Hz, which is certainly very low for a compact standmount design.