Nature sounds albums -- ''A Month in the Brazilian Rainforest'' and ''Seashore'' are two records that bring the outdoors inside

Call it heavy-mental music. Entire albums devoted to the sounds of nature, like the four installments of Rykodisc’s A Month in the Brazilian Rainforest, have been around as long as classic rock. Some of the first were Atlantic’s ”Environments” albums, recorded in the late ’60s. To commemorate their 20th anniversary, the first three of these pioneering recordings — Psychologically Ultimate Seashore, Tintinnabulation, and Dawn & Dusk at New Hope, Pa. — have been reissued on CD. Yet they haven’t aged well, from the hippie mind-melt liner notes (”If you have problems you thought only drugs could alleviate, you may be in for a pleasurable surprise”) to the flat sound quality. In retrospect, these records are the original bland New Age music, although Seashore, 60 minutes of lapping waves, may suffice if you’re looking to veg out after (or during) work.

This overall lack of sparkle becomes particularly evident when you compare the ”Environments” records to A Day on Cape Cod, Rykodisc’s vivid 1988 kickoff to its ”Atmosphere Collection.” While listening to Cape Cod‘s 44-minute ”Sunset Surf,” you’ll think you’re actually wading in the Atlantic (or, if you’re a city dweller, hearing the sound of your water pipes bursting). ”The Atmosphere Collection” also includes A Week in Hawaii and the spooky Timberwolf in the Tall Pines, which is almost as eerie as watching a preeminent werewolf flick like The Howling.

If you’re simply looking for collections of man-made sounds, don’t worry; the CD boom has revived the lost art of sound-effects records. Vol. 2 of Sonic Booms is centered around the 22-minute ”Narrow Gauge Railroad,” a slow, simmering trip that virtually puts you aboard a locomotive as it cruises through mountains, passes other trains, recouples with another train, and departs again. Did someone say ”train solo”?