Reference

Until the Recording Industry Association of America hit the headlines in recent years with its antipiracy campaign, the initials RIAA meant one thing to seasoned audiophiles: the vinyl-disc equalization characteristic introduced in the 1950s to standardize what had previously been an anarchy of different EQs. Three decades later, as CD gained ascendance, a large proportion of audiophiles still knew what RIAA equalization was, and a good number of them had some idea or better of what the RIAA EQ curve looked like, and why it was applied.

Headphones get pretty short shrift in much of the hi-fi press, which is puzzling—the headphone market is burgeoning. I don't know what the equivalent US figures are, but in recent years the UK headphone market has increased by an annual 15–20% in both units sold and overall revenue. It's easy to dismiss this as a natural byproduct of the Apple iPod phenomenon, but 20% of the market value is now accounted for by headphones costing over $120; a significant subset of consumers would seem to be looking for quality. When you also consider that many people's first exposure to higher-quality audio comes via headphones, there is ample reason for treating them more seriously.

Recently, I assessed four disparate room-correction systems based on digital signal processing (DSP): Copland DRC205, Lyngdorf Audio RoomPerfect, Velodyne">http://www.stereophile.com/musicintheround/1105mitr">Velodyne SMS-1, and Meridian">http://www.stereophile.com/musicintheround/706mitr">Meridian DRC. I concluded that Meridian's approach—which applies IIR (Infinite Impulse Response) "anti-resonance" filters to suppress room resonant modes, if only partially—was, in many respects, the best. What I particularly like about Meridian DRC is that, unlike the Copland and Lyngdorf processors, its approach to system tonal balance is largely hands-off. Yes, it lightens up the extreme bass a little, as you'd expect, but it doesn't recast the system balance in any way that might prove undesirable. If you like your system's tonal character as it is, Meridian DRC behaves just as you'd want a room-correction system to behave: it quells room resonance effects while leaving the system's essential sound well alone.