MUSIC

WORLD’S LOUDEST IPOD

iBump crossover lets you crank it up without distortion. By Tom Anderson and Wendell Anderson

Getting a big sound from portable music players should be easier. Fancy new plastic mini-speakers are everywhere, but what if you want to plug into a big old stereo and truly rock the house?

An inexpensive Y adapter cable can split a player’s headphone mini-jack into two RCA plugs for left and right channels, but you’ll get better sound if you put the low frequencies into a subwoofer and send just the mids and highs to the stereo speakers. That’s because the large movements that a speaker cone must make to produce low frequencies will distort the mids and highs — especially at high volume. Our iBump improves this situation with an active crossover circuit, which separates audio into high- and low-frequency channels. Connect the low end to a powered subwoofer, and you’ll have proper thump!

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The iBump’s crossover circuit is based on the classic Linkwitz-Riley audiophile design, which you can read about at Siegfried Linkwitz’s site ( linkwitzlab.com/filters.htm).

Some newer audio amplifiers include separate outputs for powered subwoofers and filters to keep the lows from the main speakers. We tested these and found that our iBump provides much better sound. Try it and see for yourself. This crossover sounds natural without being boomy or leaving a gap between the highs and lows.

If you don’t have a powered subwoofer, you can make one using our article “Resurrecting This Old Amp,”(MAKE, Volume 02, page 110). Start with an eBay bass amp, add large speakers, and presto: you’ll have yourself a ’quake. Or buy powered subwoofers from Klipsch, JBL, and others.

Photograph by Wendell Anderson