Jack Shafton, director sales and marketing at Paradigm, says a "stealth" sub has been a consistent request from builders and systems integrators. "It's a matter of both esthetics and square footage," he says. "The need for floor space is driving in-wall hi-fi, and the subwoofer is the final frontier of that trend."

Nashville custom home builder Michael Cronin agrees. He's been using NHT IW4 subs in both a current spec house project and in his own home. Cronin may have a bit more insight than the typical home builder. Through his company Cronin Acoustic Construction he also builds world-class music recording studios, and he feels that while in-wall subwoofers are a compromise in terms of sonic quality and quantity (of air moved), they make up for that by being invisible.

"Your partner may not want the house looking like Circuit City all the time," he says. "In-walls can be painted over and you can get decent performance out of them, as long as you isolate them properly."

Cronin uses Kinetics Noise Control's IsoMax sound isolation clips to secure the sub to the studs or joists to limit mechanical coupling, as well as adding two layers of 5/8ths-inch drywall to the rear of the enclosure. "The subs themselves aren't that expensive, but isolating them properly does incur additional cost," he says. "But it's worth it."

Al Baron is the product line manager for Polk Audio's new CSW line of in-wall subs, which range from $525 for the compact CSW 100 to $800 for the CSW 155. The line's 10-inch driver uses a neodymium motor structure to offset the unit's shallow depth. It's housed in a cast aluminum basket that is rigid and inert to suppress resonance.

Baron, who is also on the CEA's Multi-Room AV Council and the Builder Initiative between that the CEA's TechHome division and the NAHB, believes there remains a disconnect between builders and some home technology categories, particularly the "invisible" ones.

"We know from our surveys and other surveys that consumers want built-in audio, but we're also finding that to a large extent builders aren't aware of the consumer demand for the products," he says. "Invisibility equals cool, and it also represents significant profit potential to the builder because it's built in."

Low Frequencies in High Places

The ideal construction proposition for in-wall subs and speakers might be high-rise MDU residences, where floor space is at a higher premium. But it also presents the most challenges, thanks to numerous common walls between residential units.