MUSICRAFT said:
... Even though SCM19 monitors use the same dimension (150mm) Mid/LF drive unit as SCM11's however this Mid/LF drive unit (the first in ATC's range of monitors) incorporates ATC's state of the art ultra low distortion SLMT (Super Linear Magnet Technology) in a massively engineered and built assembly (which is also used in SCM20ASL Professional monitors). To put this into perpective the SLMT drive unit weighs more then a complete SCM11! In practically every area below HF SCM19's more or less show SCM11's a clean pair of heels.
Rick @ Musicraft
Speaker design is always a compromise. Whilst a closed box is arguably the better solution than having a reflex port or line, it also usually reduces sensitivity. That, in ATC's case is further exhagerated by the magnet design and probably the crossover. Its sensitivity is mediocre which, in some part explains why such a huge magnet is necessary in the first place ... power handling. It needs lots to achieve the same levels as some other, similar sized but ported designs.
Furthermore, the large magnet assembly arguably creates a highly reflective point right where you least need it ... behind the driver. Others try to get around this issue by using neodynium magnets for the bass drivers, often in unusual ways such as some of B&W's Diamond Series which places twin such magnets inside the voice coil to minimize footprint and to reduce distortion and improve field symmetry. Some use drivers with underhung magnet systems and/or 'wide open' spiders and PMC has even been known to damp the spider outriggers with absorbing materials.
I'm not saying the ATC are bad speakers but there are always trade-offs. - Simply looking at the specifications of the 19 (or even the 11), I would look for an amplifier with at least 150w/ch, such as ATC's own to fully exploit musical peaks at volume. Better still more though the Cambridge may just be enough if used sensibly. Otherwise, they are probably not to much hassle for an amplifier.
I also agree that compared to some others, ATC, materially speaking seem to offer a lot especially considering they develop their own drivers whereas others often use of the shelf units (or 'made to spec' ones) from one of the larger specialists. One is not necesseraly better than the other but it must have increased development cost for ATC, at least initially.
regards