Fahgeddaboudit – part 2 of 3

Most of us are familiar with harmonic distortion (HD). Most every amplifier, receiver, or other electronic audio component has published its harmonic distortion figures. Most electronics have vanishingly small amounts of it, but speakers produce much, much more. Yet as important as harmonic distortion is, it’s not the worst of the pack. Harmonic distortion is similar to the natural harmonics musical instruments produce, and therefore, small quantities are relatively benign. Intermodulation distortion (IMD), on the other hand, is not so benign. It’s audible at lower levels than HD.

Unlike harmonic distortion (multiples of the fundamental frequency), IMD is the sum and difference of two or more simultaneous frequencies. These sum/difference frequencies are not harmonically related, which is why they stand out more audibly. Music is made up of many notes played at the same time. Even a single note sung or played contains many harmonics from which IMD can rear its ugly head. IMD is a critical distortion.

So then, how can intermodulation be reduced? One way is to reduce the bandwidth (frequency range) of the driver and its amplifier. With a narrower range and fewer frequencies to interact, there is less intermodulation. This is why single driver speakers are particularly prone to intermodulation. Two-way speakers (one tweeter & one woofer) are an improvement. To further reduce IMD, a three-way configuration makes greater strides towards avoiding the problem. This requires a crossover, a series of electrical circuits that splits the spectrum into narrower bandwidths to feed the tweeter only high frequencies, the midrange only middle frequencies, and the woofer only low frequencies. Problems solved, right? Not yet. You still have the IMD from the amplifier. (Not to mention the mountains of other issues created by a passive crossover reprocessing the amplified signal.) There’s one more easy step we can take to bowl over intermodulation—split the bandwidth before amplification, when it’s easier to do, avoids the high level crossover issues, and send each limited band to individual amps. Now the problem is tamed not once, but twice.

Why is this distortion another one of those fahgeddaboutit problems? It’s not for lack of consequence to the sound quality. No, together these factors separate the good from the outstanding. Rather, it’s for convenience. These issues get complicated. And that’s not the only reason they’re not talked about. The number one reason is that manufacturers think you’re too stupid to understand, and what’s more, if you did understand you’d cross their speakers off your short list in a heartbeat.

Well, you’re not so stupid, and now you do understand. The Parallel Audio Project uses an active crossover and three amps, one each for the woofer, the midrange, and the tweeter. Intermodulation is greatly reduced allowing you to hear clean music.

Next topic in part 3 : resonance.

[Fahgeddaboudit, part 1]

Posted in Audio, Discover | Tagged , , | 1 Comment

Photography Is Dead

It’s taken me a long time to realize it, but it’s true. From its inception in 1839, and throughout the twentieth century, photography was a skilled profession. In the beginning it took huge amounts of time, effort, and patience. It was imprecise and fraught with limitations that demanded careful thought to make the appropriate calculations along the long chain of steps necessary to create a great image. As the years progressed, photography became a little easier. George Eastman made the first big strides towards streamlining and improving consistency to make photography available to a larger audience. Those gains continued steadily through the 1900s in each of the fields photography draws upon, chemistry, mechanics, optics, and electronics. Then, digital changed everything. At first, no, digital capture hadn’t the resolution of film, nor the contrast ratio or dynamic range. It was limited by processor speed and storage capacity. As limitations shrunk, resolution quickly caught up to film’s capabilities. But even as late as the mid aughts digital cameras were still generally lacking in dynamic range. Film continued to be the best capture medium. But gradually, wave after wave of the digital tide washed away the last grains of silver.

Now, there’s no denying it; digital has surpassed film. Photography is dead.

Photo labs are a relic of the past. Eastman Kodak, for 74 years a Dow Jones corporate giant, fizzled in less than a decade to a penny stock trading OTC, and continues to run quarterly losses after over one-hundred years of market-swamping success at leading the industry. Commercial photography has no time, or money, or need for silver based processes. (FYI : Silver halide and other photochemical processes are not analog. There is no analogy between the discrete metallic particles that make up chemical images and the lightwaves they represent. Everything that is not digital, is not necessarily analog.)

In the past, camera manufacturers used to market every new addition to SLR camera automation with the promise that anyone could take amazing profession quality photographs in a snap. Professionals knew it was an outrageous lie. The average consumer eventually found out after he/she emptied his/her wallet on a high-end SLR camera which he/she never understood or learned to master. Not today. The knowledge, the skill, and the experience necessary to create a merely passable silver image isn’t required to snap a pretty good digital image. Digital imaging has blown silver out of the water. It’s so easy. And for the most part, we can see right there on the screen exactly what we’re getting. No guessing, no worry over ISO, no light meter reading, no interpretation of the reading, no question of processing time, temperature, agitation, chemical condition, dilution. . . No question of not being able to see what you’re capturing in the camera until the end of the process, after which it’s too late to change anything, and even if you could, it also takes years of experience to effectively judge a negative by eye.

New digital cameras shouldn’t really be called cameras anymore. A digital camera does so much more than collect and focus light. Image processing algorithms start working and interpreting the scene during the capture stage before the data go to memory. It’s become so good at what it does that even the seemingly simple camera in a cell phone can make images better than most sophisticated electronic Point & Shoot film cameras ever could, to the point of automatically adjusting for light level, color balance, contrast range. Digital cameras are amazing. The advertising claims of yesterday are nearly true, now, because you don’t need to know much of anything—the camera’s internal processing does most of the work for you. No wonder the average professional photographer’s day-rate is up barely 50% from thirty years ago, and that’s in absolute dollars, not adjusted for inflation.

The world is continuing to find its way through the digital revolution. It may take several more years before the transition to digital imaging gets sorted out. In the meantime, the shock to the marketplace takes its toll on all of us. The boom in digital photography has not only pummeled photographers, it has severely lowered image quality and the expectations of quality. It used to be that the photography one saw on a daily basis was predominantly work by highly skilled professionals. In contrast, what one sees today is overwhelmingly common phone-camera pics. The bar has plummeted to limbo levels. We see mostly junk, and this new average becomes our standard of comparison. More, bigger, faster, the mantra of the digital age consumerism, kills another craft, another art.

Long live photography.

[Reality Check]

Posted in Art & Photography, Creativity | Tagged , | Leave a comment