President's Message
July 2002

1.   Listening to the popular NPR radio show "Car Talk" (which followed the audio show Shop Talk on WBUR in the early days of the BAS), I was struck by the fact that half the callers were women. Since the percent of female car buffs is probably about the same as the percent of female audio buffs (less than 2 %) I can only assume they are weighting their pre-screening to broaden the show's demographic appeal. A clue to this is that 100% of their puzzlers are submitted by men. The hosts never talk down to their callers and take the woman's side in a marital disagreement.

2.   Naxos has two new double cd sets, themed "Classical Chill" (From the Freezer, From the Fridge) and "Classical Heat" (By the Electric Fire, By the Log Fire). Starting with Rautavaara: Cantus Arcticus and ending with Barber: Adagio for Strings, it invites you to take your own temperature ratings.

3.   Roger Nichols writes in EQ (Ja02) about listening sessions for NARAS to select the "Best Engineered Non-Classical" Grammy awards. Every single CD was squashed to death, had no dynamic range and sounded like crap. Instead of listening to find the best of the CDs, he had to listen for the least offensive entries. When each song started playing, the meters on the console jumped to full scale and never dropped below -18 until the fade. No wonder that after kids download the MP3 they don't have the desire to go buy the CD.

4.   Poptronics for My02 features a construction project, "Headphone Ambience Processor." The object is to make conventional stereo recordings sound more realistic on headphones using a special crossfeed circuit. It mimics the shadowing of the head by feeding a low frequency band for the left (right) channel signal to the right (left) channel.

A first order low pass filter with a cut-off frequency of 1 kHz in each leg of crossfeeding attenuates high-frequency content. To mimic head movement, the processing includes an alternating increase of the cut-off frequency of one leg of cross-feeding at a time.

This increase, alternating in the left and right cross-feeding from the left (right) channel to the right (left) channel corresponds with head movement to the left (right) resulting in moving the right (left) ear out from the sound shadow to a greater extent. The increase factor was limited to 2, experimentally determined to not produce an apparently large disruption of the sound field of reproduction.

This random increasing of the cut-off frequency gives presence to thee sound reproduction via headphones in a similar manner as a motion picture film shot with a jittery handheld camera imparts a sense of presence at the scenes portrayed.

David Hadaway

President, Boston Audio Society


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updated 11/11/04