AUDIO ON RADIO
PCM on NPR
Radio's a natural medium for audio discussions and some demonstrations, and about 100 National Public Radio stations around the country now carry a show devoted to it. Audiophile Edition, the creation of John Sunier, is carried on the NPR satellite on Sundays at 2:00 p.m. Eastern Standard Time; some stations use PCM digital recording for delayed broadcasts.
Why bother using PCM? Because Audiophile Edition is recorded digitally to start with, and sent up to the satellite system directly from the PCM digital master, not from an analog dub, as is usually the case.
(According to Sunier, his show was the first to be transmitted this way, though the St. Louis Symphony broadcasts have since followed suit.) The associated equipment used in preparing the show includes a mouthwatering list of audiophile components too long to be cited here--Talisman cartridge, Electron Kinetics Eagle 2 power amp, that sort of thing.
The show, which is underwritten by Telarc Records and Maxell, began more than four years ago in San Francisco. It offers a mix of interviews and audiophile recordings. The recorded selections usually follow a theme, such as "The Piano on Compact Discs" or recordings with surround-sound capabilities. The interviews cover such topics as FM broadcast-signal processing, the use of ceramics in audio components, and the work of various audio designers and pioneers.
Sometimes, the recordings and the interview are built upon a common theme. For example, a show might feature synthesizer music and an interview with Wendy Carlos, or Broadway music and a discussion of audio restoration work going on at the Rodgers & Hammerstein Archives.
The December 15 show, built around just such a theme, should be of special interest to Audio readers within reach of the program. It will be the show's second annual binaural program, "For Headphone Listening Only," and will feature both binaural music and an interview with Bert Whyte on his binaural work.
Audio on a Wedding Eve
I recently spent a day selecting and taping 22 cuts of music to precede and follow my wedding. It made me more aware of where CD and LP stand in relation to each other, and of the differences between the two which don't show up on spec sheets but help define our experience of the two systems.
On repertoire, LP wins, hands down. At best, a fourth of the 22 cuts I taped could have been assembled from CDs, if I'd had them, but about three-quarters were on LPs now in print, the rest on older LPs. As it happened, I had one of the albums on both LP and CD, so I used the latter for one cut.
There is far more satisfaction, I admit, in playing records than in playing CDs. With LPs you get the pleasure of what Anthony Cordesman calls the purification rituals (one for disc and one for stylus), and an intimate involvement with precision machinery as you swing your tonearm over to the cut you want and set it down, gently and precisely, in the lead-in groove. Sometimes, even, there is more fidelity, especially when you compare an nth-generation audiophile turntable system with a first-generation CD player.
Still, if I could have done it all from CD, I would have-and gladly.
Records are a lovely nuisance. I don't want to purify my records and my stylus every time I play a disc, especially when my newly cleaned records still come out sounding hissy and still get my stylus grundgy halfway through. I guess I need a record-cleaning machine, but even the cheapest ones are hardly cheap.
A damp cloth to clean my CDs costs less and takes up less space.
When you cue up a cut on CD, you don't have to worry about denting the disc or chipping the stylus, should you let the arm slip. When you're taping from CD, you don't have to start with the last few seconds of the previous cut so you can gauge when the cut you want will actually begin. If you want to tape part of a cut, you can use the CD player's time display as an exact guide to when the desired section will begin and end.
(On some players-though not mine-you can even preset start and end points and let the player do your edits for you.) This sort of dubbing-all from commercial records-is part of what the record companies are up in arms about. Yet what alternative had I? There was no way I could have segued all those records neatly in real time, and as the groom, I would have been unavailable to try. And while rd gladly have bought a commercial tape of what I wanted, where would I have found one? My ultimate selections ranged from Bach to Basie and came from 14 separate albums, most from different record companies, at least one from a record never sold in the U.S.--and all discs I already owned.
Yet how much pleasure my guests and I got from all the record companies' and musicians' work and from mine, assembling it! It's the music that matters. We of the audio industry are just here to help.
Portable News
Every public pleasure is proclaimed a plague-you may remember the warnings of incipient blindness aimed at early TV owners, and you should have heard the cries of sin at the introduction of the waltz! So it's no surprise that, when the Walkman and its imitators grew ubiquitous, we started hearing dire warnings that continued use would cause deafness.
And people do play them loud-often enough so that you can make out, from yards away, just what they're hearing. I've often warned such loud listeners to protect their hearing by turning down the volume. It seems I'm only half right in this.
Sound and Vibration recently reported that the cries of doom may be unfounded. Dire early reports, says contributing editor Larry H. Royster, presumed full-time use at full volume.
In practice, distortion limits usable output levels (even for average listeners, who tolerate a lot more distortion than most Audio readers), and listening is not quite continuous, either. Royster's measurements of actual listening show that moderate levels are most common: For average (50th-percentile) listeners, average levels are equivalent to external diffuse-field sound levels of 52 dBA in quiet interiors, 71 dBA outdoors, and 83 dBA with typical, on-the-job background noise levels of 80 dB.
The top tenth of the people surveyed-those who listened to the loudest music-used levels equivalent to 64 dBA indoors, 83 dBA outdoors and 92 dBA with 80-dBA background noise. "For the most sensitive 5% of [the industrial] population," says Royster, "the expected increase in hearing loss over 20 years of noise exposure would be 4 dB at 4 kHz, an effect that is most likely acceptable to the employees in the type of work environment investigated, where the job function is very repetitive." I'm not sure that music lovers and audiophiles would accept this hearing loss as readily, especially if added to the other hearing losses we can expect from aging in a mechanized environment. But at least we need not issue blanket condemnations of headphone listening.
Royster does, however, have some words of warning: Users in high-noise environments should be warned of potential hearing loss. Managers of noisy facilities should conduct annual audiometric tests of headphone users and non-users, to check for signs of headphone-induced hearing loss.
And listeners who already show significant, permanent noise-induced hearing losses should not use headphone portables.
Do the headphones attenuate outside sounds significantly? If so, while perhaps protecting the users' hearing, they might endanger listeners by isolating them from outside warning sounds. This, however, Royster and three colleagues report, is unlikely. Supra-aural phones (the typical Walkman type, which sit on the ear) had a modified noise-reduction rating of only 0.3 dB for straight-ahead or side sounds. Circumaural (ear-surrounding) phones attenuated straight-ahead sounds by 1.9 dB and side sounds by 1.2 dB. Semi-aural (in-the-ear) phones had attenuation figures of 0.6 and 2.6 dB.
Good news for headphone listeners may also turn out to be good news for those who'd rather not hear their neighbors' music, if it encourages those nearby to listen privately-not that the average loud-portable listener has any care for incipient deafness, near as I can tell.
New York City has now set aside areas in some parks and beaches where, to quote the newly erected signs, "Playing of radios or tape players without earphones is PROHIBITED." Violators are subject to $50 fines and risk having their portables impounded. There were some grumbles; The New York Times reported one man as saying, "As long as you're not annoying someone else, you should be allowed to play your radio. It's soothing," and cited a mother's fears that headphones would prevent her from hearing her young son. But overall, the restricted areas are quieter.
Why not just prohibit loud radios? Because that would either involve police in judgments that might not stand up in court, or require that they carry--and know how to use--sound level meters.
New Arrival
New-product announcements usually go in our "What's New" section. But this one, submitted by Mitch Kawasaki of Rotel, seemed to belong here:
Kawasaki-Mitch and Darlene (nee Spencer) are pleased to announce the safe arrival of Rebecca Kiyoko and Katelyn Miyoshi. This exclusively limited-edition pair of twins weighed in at 4 lbs., 13 oz. and 4 lbs., 12 oz., respectively. After 37.5 weeks of detailed preparation, the diminutive pair was born simultaneously on May 11, 1985, at McMaster Medical Centre. They exhibit twin absolute phasing, with direct/reflecting time-aligned coherency, having been meticulously matched to within ±1 oz. Both left and right channels are water-cooled, with no warmup necessary. For peak performance, breast milk at on-demand frequency has been selected. They have already exhibited excellent dynamic range and frequency bandwidth. SPL has been measured to be 105 dB.
Respiratory Failure
In stating, correctly, in the August 1985 issue that using Dolby B NR and dbx NR together would eliminate the tatter's "breathing," I stated, incorrectly, that that breathing was proportional to noise in the input signal. Actually, it's proportional to the noise in the recording medium which is why the problem is more often heard in dbx cassette recordings than in open-reel tapes made with dbx.
Wrong Number:
The price quoted for NEC's AV-300 surround-sound processor in the September column was incorrect. The correct price is $499.
(adapted from Audio magazine, Dec. 1985)
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