Tag Archives: audio

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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.

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Transient considerations

There are a lot of parameters audio design engineers must consider when crafting a new amplification circuit.

Chief among them is the dynamic ability of a circuit to properly reproduce transients.

Transient response in an audio system refers to how quickly and accurately the system responds to changes in the audio signal, particularly fast, brief changes. Take for example the pluck of a string or the blat of a trumpet.

If we were to resort to a car analogy it might be described as how quickly one can go from zero to 60.

Staying with that analogy, it should be obvious that there is a finite time required to go from zero to whatever. Also, what happens when you get to 60 mph? In an audio circuit, it’s important to be able to move from a zero state to a loud state and then back again. Think of what happens when a drumstick strikes a drum head. Quick on, quick off.

As engineers, we look at some pretty well defined parameters when considering transient response. They include:

  • Rise time: This is the time it takes for an audio signal to rise from 10% to 90% of its maximum value. A faster rise time results in a more defined transient response, allowing for more accurate reproduction of fast-changing signals.
  • Slew rate: This is the rate of change of the output signal over time, and it is directly related to the ability of the system to respond to changes in the input signal. A higher slew rate means the system can respond more quickly to changes in the input signal.
  • Overshoot: This is the amount by which the output signal exceeds the final steady-state value. Too much overshoot can result in distortion, while too little can result in a lack of detail in the transient response.
  • Settling time: This is the time it takes for the output signal to reach its final steady-state value after a change in the input signal. A shorter settling time results in a more accurate transient response, while a longer settling time can result in smearing or blurring of the transient information.

Like harmonic or intermodulation distortion, any loss or modification of the signal’s transient response impacts sound quality.

For those enamored with choosing which stereo gear to buy based on measurements, this is but one example of an important factor in sound quality that is almost never mentioned or quantified in published measurements.

Just sayin’.

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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.

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Adjusting focus

Knowing where to focus one’s attention is often difficult in our technically complex world. Take, for example, the case of fiber optics.

We know that galvanic isolation can make a big difference in digital audio. Any owners of the new DirectStream MK2, with its ability to switch on and off the isolation of every input and output for best sound, can attest to the benefits of customizing levels of galvanic isolation.

So, it should be no surprise that fiber optics is one of the easiest means of galvanic isolation in digital audio. Sending digital audio data over a piece of plastic in the form of light waves turns out to be as perfect isolation as one can get.

And yet using a TOSLINK fiber optic cable is a sonic step backward (even compared to lowly coax).

What gives?

The problem with TOSLINK isn’t its lack of isolation feature. Instead, it’s a problem with sacrifices.

What did you give up to gain the benefits of isolation?

Bandwidth and quality of signal transmission are severely compromised in the mainstay implementation of TOSLINK.

You gain the benefits of isolation at the expense of bandwidth and signal veracity.

Fiber optics, when done right, are wonderful sounding and without compromise.

One must always adjust the focus on where to point one’s full attention.

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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.

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Success meter

If you’ve ever been to an audio show, you know the differences in stereo systems and loudspeakers can be extreme.

In one room, if you are fortunate enough to get the center seat, you’re required to put your head in a vice in order to enjoy perfect imaging.

In another room there’s a wide sweet spot that, while not as specific as the last room you visited, offers a broader perspective.

Still another room hasn’t any real bottom end but man! has it got dynamics.

And then there are the rooms that you do not even go in.

Room after room sounds remarkably different. Each room touts its system as state-of-the-art—something that clearly cannot be true unless there are a lot of possible states or the art category is very broad.

When we set up for a show, I am most pleased when I see lots of grins on the faces of listeners.

Repeat visitors are a blessing as well.

Once I am pleased with the system’s performance, it is the joy on people’s faces I watch for most.

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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.

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Methodology

Few things in engineering are straightforward. In fact, more often than not, how you do something is more important than what you do.

Take, for example, the task of audio PC board layout.

Back in the day—and that day goes back 40-something years—there were no such things as computers available for PC board layout tasks. At least not for mere mortals. Instead, rolls of sticky black tape and sheets of stick-um donut pads of all sizes were the norm. Armed with a razor blade as my only tool, I would spend days hunched over a light table rolling out circuit traces terminating in those through-hole pads.

The goal, of course, was to make a master from which circuit boards would eventually be mass-produced and used in the building of PS Audio amplifiers and preamplifiers. That was what we did back then. (unlike today, where all this is done on a computer in what looks somewhat like a build-it-yourself video game where pads and traces can be moved around at the click of a mouse)

The problem with hand placing parts the “old way” was twofold: getting everything to fit onto a predefined PC board size and routing all the traces without running into each other and shorting out. I spent countless hours/days ripping up my work and starting over until I devised a new methodology.

That new methodology involved a sheet of styrofoam and a box of all the parts I would need. Onto the styrofoam, I would insert the parts and move them around like chess pieces until the jigsaw puzzle of one hundred or so parts all fit in neat and orderly rows. Once placed, I could draw the major power supply routes and signal connections with a pen to make sure it all worked.

What I was doing never varied much, but how I did it mattered greatly.

From that point on, the quality and beauty of PS Audio boards to a major leap forward thanks to methodology.

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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.

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Fighting the good fight

It should be no surprise that 99.9% of the developed world has audio quality available to them that far exceeds anything they might hope for. And that quality sound is available from a several million title library.

What an amazing time to be a music lover.

Imagine back a mere 40 years ago telling your younger self that at the touch of a finger, you could enjoy any music at a quality level you might only dream of.  That’d be right up there with self-driving cars and Dick Tracey wrist phones. Impossible!

Yet, here we are and, of course, our reference levels of what’s possible have been upgraded. Sound quality that 40 years ago would have put me over the moon doesn’t interest me at all today. Not when I can have what’s currently in Music Room 3.

All this progress we enjoy comes from members of our small community fighting the good fight. As technology develops better means of recording, storage, and playback, it is up to us audiophiles to keep pushing forward the technological boundaries of what is possible.

Supporting great recordings, upgrading our equipment, tweaking our systems until they blow us away.

That’s a fight worth fighting for.

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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.

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Accidental discoveries

Many of the products of science we take for granted were discovered by accident: penicillin, Viagra, anesthesia, the microwave oven, chewing gum, brandy, and even silly putty.

The key to those discoveries lies in the inventor’s openness to observations unrelated to the original experiment. Take for example, when in 1879, chemist Constantin Fahlberg went to dinner after a day of experimenting with coal derivates. As he ate dinner, he noticed something tasted particularly sweet, which he later traced to a chemical compound he’d spilled on his hand. That observation lead to the first artificial sweetener, later known as Saccharin.

On a far smaller scale, it brings to mind the time Stan Warren and I were evaluating a new circuit topology and, out of necessity, substituted the proper power transformer with one of the same voltage but 10 times the correct size. The audible difference between the correctly sized transformer and the massively oversized version was nothing short of extraordinary.

If we had been measuring the circuit’s audio performance instead of listening to it we would never have discovered the benefits of oversized power transformers.

There’s much to be said for the experiential experience.

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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.

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Hmmmm

Less than obvious choices

Now that we’ve moved the main PS Audio reference system from Music Room Two to Music Room Three we have a new challenge at hand. Where formerly the problems in MR2 were a loss of low end (a severe suck out from 100Hz and below), now we’re noticing in MR3 a kind of lackluster presentation.

Call it a loss of musical life.

Following my own advice found in The Audiophile’s Guide: The Loudspeaker, I have spent a great deal of time getting everything in balance. Only, no matter what I do there continues to be this lack of musical aliveness.

And this means I cannot get to where we need to go by setup alone. It is time to turn to the room.

First, a little history.

Neither music rooms two nor three have great dimensions. We did our best to turn a bouncy-floor mezzanine into the best rooms possible. We then spent a goodly sum of money in MR3 hiring a sound engineer to measure and condition the room with corner traps and wall absorbers for an even frequency response. It measures correctly now and so we moved the reference system in place.

Back to the story.

Late one Sunday afternoon, after spending hours of frustration working to get some life into the system, it occurred to me I was trapped inside conventional thinking. I had taken for granted the room treatments we enacted were right. After all, I had seen the acoustic measurements of the room and they looked correct.

I had broken Paul’s rule. If you can’t get where you need to go, think outside the box.

Blog Posts

Asheville, Walnut Cove, Biltmore Forrest and Western North Carolina Audio and Home Theater specialists present Cane Creek Audio and Paul McGowan of PS Audio, Intl.

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Robot discrimination

Begin non-audio related rant…..

We are all familiar with websites (like our own) requiring us to prove we are human.

Sometimes it’s a simple checkbox certifying your humanness.

Other times it’s a challenge to see if you can pick out certain features from an image.

All to prove you are not a robot.

Robots are not welcome here.

If I were to step back from the day-to-day immersion of being here now and mentally put myself 10 years back in time, I would be dumbfounded to see us discriminating against robots.

Author Isaac Asimov would smile, as would every other science fiction writer predicting the rise of the machine.

Back to the present day. We all understand that “robot” isn’t really an anthropomorphic creature sitting at a keyboard. In this case, it’s an unwanted computer program searching for a way into our website with the intent of causing us economic harm or simply wreaking havoc for the fun of it.

But what happens in another decade when very human-like creatures with good intentions wish to join the party?

We haven’t yet figured out how not to discriminate against our fellow humans.

Are we facing yet another challenge?

Easy to say robots don’t have feelings.

End non-audio related rant.

Blog Posts

Asheville, Walnut Cove, Biltmore Forrest and Western North Carolina Audio and Home Theater specialists present Cane Creek Audio and Paul McGowan of PS Audio, Intl.

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Art or science?

I am often asked whether high-end audio is an art or a science. Of course, the convenient answer is both.

Maybe a better question would be the degree to which the two are divided.

At PS Audio, the balance between art and science varies depending on the project’s phase.

When we first dream of a new product it’s almost purely art: dream about what we would like to have in our own systems without any concern for the technological hurdles.

The next phase is where we roll up our proverbial sleeves and generate schematics specific to the various systems that will be required: experience from prior art coupled with a lot of science.

Phase 3 is a 50/50 mix of art and science: how does it sound and what should we change to maximize performance? It is often necessary to think outside the box.

Phase 4 is all science: test, measure, test again.

But that’s just us. Other manufacturers bounce around from zero art and all engineering science to a myriad of other combinations.

When products become personal you know there’s a good blend of both art and science.

Blog Posts

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.

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I smell a new DAC coming from PS Audio!

Keeping time

We’re all aware that jitter in the digital audio stream is to be avoided.

Jitter is all about timing deviations where the audio data isn’t exactly where it is supposed to be in time. You can think of it like someone being early or late for their scheduled arrival time.

For jitter to be audible it has to be unpredictably late or early. (If we know the data is always late or early by the same measure then it’s easy to compensate).

The reference for our digital audio data is called a clock. With every clock cycle, the digital audio system looks to see if there is any incoming data that arrived on time. If there is, life’s good. If that data is slightly late or early, we get a “jerky” output of digits fed into our DACs.

To make certain this doesn’t happen we often add queues (buffers) where we collect all the on time, late, and early data together before passing them on to their final destination.

This digital queue describes perfectly PS Audio’s Digital Lens technology.

Here’s the thing. Data stored on a hard drive, streaming over the internet, or your home network don’t have too much of a schedule to worry about. Think of them as travelers told to show up at a certain time and place where they are then expected to join a queue before being assigned to a time schedule.

In other words, stored and streamed data don’t have clocks that are important to their final arrival time. Thus, they cannot have jitter to worry about.

Only when we enter the world of master clocks as dictated by (for example) CD/SACD transports do we need to worry about jitter. (In these cases the transport supplies the master clock to the DAC)

Data entering a DAC must at some point fall in line to be properly queued up and marched in time so as to avoid jitter.

Where that happens is all important.