SP Acoustics are a new loudspeaker company recently founded by Steve Phillips, a former employee of Acoustic Energy, and they’ve just announced their first entry into the studio monitoring market: the SP1M.
A floor-standing monitor, the SP1M houses two 6.5-inch bass drivers, a four-inch mid-range driver and a 0.75-inch tweeter, all of which are integrated into a large (120 litre!) sealed cabinet. The use of a sealed enclosure (or ‘infinite baffle’) would appear to be in line with the current trend for improved time-domain linearity compared with the more common ported-cabinet approach, but this is no bandwagon company: in fact, it’s probably fair to say that Phillips is himself partly responsible for the recent increase in the popularity of infinite-baffle speakers, having been involved with the design of the well-received Acoustic Energy AE22 monitors. However, although they are also sealed-box designs, the AE22s reside firmly at the opposite end of the market from these latest creations (we’ll come to the price later, but suffice it to say you’ll want to be sitting down).
Of course, sealed enclosures have been around for several decades (Phillips says the SP1Ms are “based on trusted design principles from the ’70s”) but, fuelled by consumer ignorance, the hi-fi market has long favoured ported speakers for their augmented bass response, at the expense of increased group delay and a smeared lower-mid range, so while ported cabinets do allow for increased driver excursion at low frequencies, they also allow the driver to ‘ring’, which is far from ideal in mixing and mastering situations, where the timing of low-frequency elements like kick drums and basses needs to be assessed critically, particularly when applying processing such as compression.
The trouble with infinite-baffle designs, conversely, is that low-end extension is harder to achieve as driver excursion is impeded by the sealed volume of air inside the cabinet. However, this being effectively a cost-no-object speaker, Phillips has a solution: an “oversized”, under-hung neodymium magnet endows the bass driver with an impressive ±16mm excursion. Furthermore, distortion is minimised thanks to the SP1M’s large cabinet, which Phillips says presents the bass drivers with an equal amount of pressure to both the front and rear of the cone.
The four-inch mid-range driver also benefits from a large magnet assembly, which, as on the bass driver, reduces thermal compression and increases linear excursion. The tweeter, meanwhile, is a 0.75-inch soft-dome type and, once again, powered by a neodymium magnet.
The SP1Ms boast a frequency response of 40Hz to 35kHz (±3dB), and a sensitivity of 92dB. Nominal input impedance is 6Ω, and the speakers come with either single-wired 4mm binding posts, Neutrik Speakon connectors, or they can be hard-wired with Chord Solstice cables, cut to a length of your choosing.
And finally, SP Acoustics say that the sealed-cabinet design makes the speakers suitable for soffit-mounting — but if you do intend to mount the SP1Ms in your control room walls, make sure you budget for the structural work required after you’ve bought them — the SP1Ms retail at £11950 per pair.
