Asheville, Walnut Cove, Biltmore Forrest and Western North Carolina’s Audio and Home Theater specialists present Cane Creek AV and Paul McGowan – PS Audio, Intl

Cool history lesson from Paul.

Hertz

I can’t begin to count the number of times I’ve written the abbreviation, Hz—1 kHz, 1,000 kHz.

It is, of course, short for Hertz.

The car company?

Heinrich Rudolf Hertz was a German physicist who first proved the existence of electromagnetic waves. Invisible forces that had a specific periodicity (frequency) that later were named in his honor.

Invisible waves were first proposed by a Scottish fellow, James Clerk Maxwell (no, not the hammer murderer Maxwell Edison) who first connected the idea that three forms of energy—electrical, magnetic, and light—were all related to each other. To make it even more interesting, they all seemed to travel at the same speed (the speed of light) and they all acted in the same way (like waves). He summed these conclusions up mathematically in what later became known as Maxwell’s equations.

It was our friend Hertz (no, not the owner of Hertz Drive-Ur-Self System), who would not only prove that which no one had yet shown, that electricity and magnetism could travel through space as waves (like visible light). It was easy for people to wrap their heads around the idea of light traveling through space because we could see it. But invisible electricity or magnetism? These were spooky, invisible, phenomena.

Hertz not only proved Maxwell’s Equations were correct, but in so doing, he also invented the first radio transmitter.

“Hertz’s first radio transmitter: a capacitance loaded dipole resonator consisting of a pair of one-meter copper wires with a 7.5 mm spark gap between them, ending in 30 cm zinc spheres. When an induction coil applied a high voltage between the two sides, sparks across the spark gap created standing waves of radio frequency current in the wires, which radiated radio waves. The frequency of the waves was roughly 50 MHz, about that used in modern television transmitters.”

Unfortunately, Hertz suffered from massive migraines and in 1894 died at the young age of 36 after complications in surgery to fix his condition.

Seems medical science was considerably farther behind than physics.

Asheville, Walnut Cove, Biltmore Forrest and Western North Carolina’s Audio and Home Theater specialists present Cane Creek AV and Paul McGowan – PS Audio, Intl

Too many “weeds” here from Paul, but interesting to some.

Sample rates

There sure is a lot of confusion over sample rates. We hear about CD-quality sample rates at 44.1kHz (and its multiples), or another common sample rate, 48kHz (and its multiples), and then there are multiple higher sample rates (176kHz, 192kHz as examples) and of course DSD.

Lots of numbers. All very confusing.

Perhaps a short primer would help.

First, what is a sample rate? Simply put, it’s a snapshot of the audio signal. A slice of time where we capture the voltage level of the music signal. The number of times per second we take that snapshot determines the sample rate. (Bit depth determines the loudness range we can capture within each sample)

First, what’s the difference between 44.1kHz and 48kHz and why do the two exist? The former is what Sony/Philips set as a standard for the Compact disc. When we do higher sample rate versions of this standard we get 88.2kHz, 176kHz and so forth. The latter, 48kHz, is the standard the “pros” use (because, well, they can’t use something as conventional as consumers, now can they?). 48kHz gives us multiples we’re familiar with like 96kHz, and 192kHz.

What’s painful about the above two standards is the difficulty moving between them. When recording studios record at “pro” sample rates of 48kHz they then have to interpolate down a few Hz to 44.1kHz to make something we poor consumers can listen to.

Silliness.

When we nerds talk about sample rates we use different terminology. We base our discussion on how many multiples of the base frequency (44.1kHz) are in play. So, for instance, the CD sample rate is referred to as 1fs. Its multiples are 2fs, 3fs, etc.

The sampling frequency or sampling rate, fs, is the average number of samples obtained in one second (samples per second). Think of 1fs as the minimum baseline to capture 20Hz to 20kHz.

While we might be familiar with all the differing PCM sample rates, DSD brings in a whole other dimension with its far higher sample rates. For example, standard DSD is 64fs while double rate DSD is twice that at 128fs. So what’s that mean? Well, 1fs is running at 44,000 times per second, while 64fs is running at 64 times that frequency, or 2,822,400 times per second! That’s fast, man.

And, while DSD is so much higher of a sample rate as to raise a few eyebrows, it’s instructive to remember it’s a 1-bit system compared to a basic 16-bit system like PCM (remember that the number of bits is needed to measure amplitude). This boils down to something less hair raising if we do a bit of math. 64fs (1xDSD) runs at a very high clock rate of 2,822,400 Hz (2.8mHz). Now, simply divide that by 16 (the number of bits in a PCM word) and guess what you get? A sample rate of 176kHz. Sound familiar? 176kHz is the same as 4fs PCM. So, while PCM requires 16 bits to adequately measure amplitude, and DSD needs 16 single bits to do the same, it all kind of works out in the end. (Don’t take what I just wrote about DSD and 16 bits as literal. I use it only as a means of helping form a picture. DSD is far more complicated, using a Sigma-Delta Modulator, noise shaping, etc.)

Without getting too much more in the weeds, that’ll give you a brief simplistic overview of sampling rates.

Asheville, Walnut Cove, Biltmore Forrest and Western North Carolina’s Audio and Home Theater specialists present Cane Creek AV and Paul McGowan – PS Audio, Intl

Loudspeakers designed and measured to sound flat in an anechoic chamber will sound terrible in a real life listening room environment. That’s just the way it is.

The price of flat

There’s really no such thing as a flat loudspeaker.

Loudspeakers are such inaccurate mechanical devices that if one were to attempt a flat frequency response, enormous levels of compensation would need to be applied. And, even then, those compensating changes in amplitude would only work in a very small area.

Unlike an audio amplifier whose input vs. output is fairly straightforward, speakers present an enormous challenge—one that depends on so many outside variables (box, baffle, room size) as to make it a non-starter.

The price of flat, as it pertains to loudspeakers, is equivalent to the price of peace.

Unaffordable.

Not to despair. Fortunately, our ear/brain mechanisms are powerful enough to adjust so that when we listen, it sounds “flat”.

And at the proverbial end of the day, if it sounds flat then it is flat.

Problem solved.

 

Asheville, Walnut Cove, Biltmore Forrest and Western North Carolina’s Audio and Home Theater specialists present Cane Creek AV and Paul McGowan – PS Audio, Intl

Decaf

The taste of decaf coffee isn’t the same as caffeinated, in the same way that Diet Coke, vegetarian bacon, or high-end MP3 players aren’t the same as what they started out as.

It’s good we call out differences between the original products and their derivatives, but at times it can seem a bit odd. As vegetarians, we enjoy a meat-like substance that resembles strips of bacon, but bacon it is not. Were it actually animal flesh we would not eat it.

The fact it isn’t what it purports to be is the reason we engage with it.

Take for example a product said to have a tube-like sound. We ignore the fact it is 100% solid-state because that description might not connect with our image of good sound any more than a package of Vital Wheat Gluten, Canola Oil, Adzuki Beans, and Buckwheat Groats seems appetizing.

It’s bold indeed to produce products that stand on their own merit and challenge stereotypes: AC regenerators, separate phono preamplifiers, CD transports, vibration control feet, active grounding systems.

I love the taste of a great cup of coffee, caffeine, and all.