Asheville’s Home Theater and Audio specialist presents Cane Creek AV and Paul McGowan – PS Audio, Intl.

Cubs

Whenever I go to an audio club to speak and explain what we do I am always worried about expectations.  For example, at the Arizona Audio meeting on Wednesday, the expectation of the group was for me to demonstrate to 40 or more people, in a hotel meeting room, all that they’ve been missing on their CDs.

That’s always a little daunting to me: I am playing music most are not familiar with, the room is usually suspect, the system unknown and really, what would one expect other than “eh” results?

But sometimes you get lucky.  And in this case, I have Dave Wilson to thank.  I haven’t heard a Wilson speaker in a number of years, but I know he makes great devices.  I also know they’re traditionally a tough setup that requires a lot of work.  Much to my surprise, when one of the audio club members totes in a small pair of Wilson Cubs on stands, we connected them up and they were wonderful.  No setup at all.

We added one of the older Genesis Servo 12 subwoofers to the mix, powered the system up with DirectStream feeding a NewClear power amplifier directly through MG Audio Design balanced interconnects and whoa!  The system sang wonderfully.  I don’t think anyone attending failed to have their jaws drop when we played good old CDs.

Hats off to the Wilson design team for a job well done.

Asheville’s Home Theater and Audio specialist presents Cane Creek AV and Paul McGowan – PS Audio, Intl.

35 foot tall Buddy Holly

Tom came by the office the other day to hear Music Room One.  We had a good time together playing lots of music through DirectStream.  Hearing music in Music Room One is a real treat for most people.  Tom wasn’t disappointed.

A couple of tracks we played were too loud for him, he asked I turn down the system from where I have gotten used to listening to it.  Tom was very particular about the level (as we all should be) and when we reached the perfect level his hand went up and a smile was on his face.

A few days later I got a note from Tom asking about what he’d heard.  The cut in question is one most everyone likes: a 1959 recording of Buddy Holly singing True Love Ways.  It’s amazing this is on a CD and recorded so long ago and when played through DirectStream it sounds like you’re in the studio.  Most high resolution audio doesn’t sound this good.  Tom said “I have never heard a 35 foot tall Buddy Holly.”  What intrigued Tom even more was when we reduced the level, Buddy Holly regained his 6 foot height in perfect proportions.  The volume control acting like a height distortion lens.

Of course Tom was right and I have written about these issues many times before.  There is a perfect volume level for each recording that differs from system to system, room to room.  In the past I have been rather scrupulous with these settings, to the point of writing down the correct level setting for each track to make sure.

Since most of my time in Music Room One has been spent listening to DirectStream and all its development, I have found myself turning the level up to a higher setting than is appropriate to the music.  Why?  Because turning the level up past its perfect point is like looking through a microscope at the music, searching for tiny little details that might need attention.  In fact, I had gotten so used to doing this that I’d forgotten that wasn’t what Tom was interested in.

He did remark that a 20 foot Shelby Lynne, a 35 foot tall Buddy Holly and an 8 foot Chairman of Board (old blue eyes) was an experience he will never forget.

Thanks Tom, appreciate the help and reminder.

I’ll be speaking tonight at the Phoenix Airport Marriot if you’re in the neighborhood.  Come on by.

Asheville’s Home Theater and Audio specialist presents Cane Creek AV and Paul McGowan – PS Audio, Intl.

How to make an iPhone with a shovel

I have very strange thoughts running through my head.  Thank goodness I have you to share them with.  Otherwise, they’d be stuck inside with no way to get out.

Given another couple of decades of progress in technology, the rate of which is increasing exponentially, a marvel like the iPhone will be passé.  Passé to the point of us shaking our heads at how Neanderthal-like we all were at the time.  We will no doubt communicate with each other using invisible devices, no longer tethered to the requirements of a physical handheld device.

But imagine what an iPhone would look like to Fred Flintstone.  Try mentally imagining how you would explain to old Fred and Barney how this amazing jeweled looking wonder came from simple elements in the earth, elements that Fred and Barney have at their disposal: tar, dirt and sand.  To them it would be sorcery; even to someone of the Bronze Age who understands how to convert what comes out of the earth with a shovel into metal to make a sword it would be magic.  Arthur C. Clarke’s great quote comes to mind.  ”Any sufficiently advanced technology is indistinguishable from magic.”

What we take for granted is an accumulation of all we’ve been since we first emerged on the earth millions of years ago.  When we dream about traveling to the stars, transporting ourselves along with Captain Kirk, or ordering a cup of Earl Gray from a machine,  it’s easy to forget what it took to get where we are.

And when I look at my listening room, I am humbled to think all of what’s there came from a few trees, a pile of dirt, sand and a few cups of oil.  That’s truly remarkable.

See?  I told you strange stuff rattles around up there.

Asheville’s Home Theater and Audio specialist presents Cane Creek AV and Paul McGowan – PS Audio, Intl.

Live vs. recorded

Terri and I went to enjoy the Boulder Philharmonic last night at the university and we were able to get great seats: 7th row, center, slightly to the right.

Closing my eyes and listening to the cellos I mentally compared the live sound to what I am getting in Music Room One: nearly identical.   The only thing lacking was a presence and immediacy in the upper regions where the bow hits the strings.  But more intriguing to me was a reminder of how different the soundstage is.   In a typical recording, the microphones would be on stage, much closer to the musicians than I ever would be.  Live, I am 7 rows back from the orchestra where the room adds a huge impact on the sound.  If the engineer were to place his microphones where I was sitting, the sound would not be the same as I was hearing live, when played back, because the microphones pickup everything, ignoring nothing.

What I hear 7 rows back includes a lot of the hall and audience impacts that my brain is ignoring as I focus on just the music coming from the stage.

When I listen to a relatively closer mic’d recording on my system, my brain has to make up for everything in my listening room, the differences in how close the microphones are to the musicians, relative to where I would normally sit in a live setting, etc.

The instruments sound nearly identical in both situations, to me, but the space can never be the same.  On a well recorded piece, the view I get can sometimes be even better than what I hear live; just as watching sports event live vs. on television can be an enhanced experience because of the closer camera advantage of TV.

Hearing it live helps center me and gives a very different feeling than hearing it recorded, but both have their advantages.

Asheville’s Home Theater and Audio specialist presents Cane Creek AV and Paul McGowan – PS Audio, Intl.

Back to the classroom

Thanks for indulging me my story of the early struggles with an outdated education system.  I hope we’ve come a long way since those days of industrialized factory schools churning out something; although I am not sure what.

The saving grace of my education through public schools was the few standout teachers I had (and I suspect you had as well).  Hats off to those brave souls that really loved to teach and share and gave their all towards that endeavor, despite an antiquated school system that hadn’t changed much since it started, back in the Henry Ford days.

Let’s finish up with DoP and move on to other subjects.  If you’ll recall, DoP is a format that permits single bit audio (DSD) to “trick” a computer or network into thinking its Multi-bit Audio (PCM).  Because computers don’t recognize Single-bit Audio, they don’t know what to do with it.  And that brings me back to what I asked you to memorize: that Bits are Bits.  To a computer a video bit, math bit, audio bit, or mouse bit all look the same.  Bits is bits.  Remember?

Now, don’t get turned around just yet.  Many of you wrote in to say “if bits are bits, why do cables matter, sample rates, etc.?”  Ok, that means you’re thinking too much!  I’ll likely call Mr. Shannon out of retirement to give you a good whack for doing so.  🙂  When I write “bits are bits” I am not referring to how those bits are delivered, their speed, their timing and all the little details critical to how those bits are going to sound.  No, I am referring to the bits themselves: the ON and OFF pulses are all pretty much the same.

So if bits are bits, how do Single-bits differ from Multi-bits and how does a computer know the difference?  Computers use something called a header, which is a small group of bits that represent an instruction set.  The header always comes first and tells the computer “I have PCM or I have DSD or I am USB” and with these instructions, the computer (or DAC) knows what to expect next and what to do about it.

The problem we run into with Single-bit Audio is two fold: it’s a stream and doesn’t have a consistent “reminder” header telling the computer what’s going on and most modern computers were never instructed to deal with Single-bit Audio even if they did have the instruction set.  They only know Multi-bit Audio.  Think of this as getting a set of written instructions in a language you can’t understand.  That could change, over time if operating systems of Microsoft and Apple wanted to include Single-bit audio, but for now they don’t.

So here’s what some clever guys did to get around this problem: they put sheep’s clothing on the pack of wolves.  If you had a flock of sheep and wanted to get a pack of wolves into that group without the sheep noticing, you’d wrap the wolves in sheepskin so the sheep would be fooled.  Now let’s relate that to Single-bit Audio (the wolf) and Multi-bit Audio (the sheep).

Single-bit Audio is a stream of on/off bits.  The more ON bits the more energy we generate to make a loudspeaker move.  Multi-bit Audio is not a constant stream, but rather a stream of coded packets (their bits also make more or less energy to the loudspeaker, but they must first be decoded, unlike the simpler Single-bit stream).  Think of Single-bit Audio as a flowing stream of water and Multi-bit Audio as a long unbroken freight train.  Each of the cars in our imaginary freight train has an identifying marker that lets an inspector know what’s inside each of the cars of the train.  This is the header I spoke of.

If we want to take our continuous stream (Single-bit Audio) to a new location, one thing we could do is divert a section of the stream’s water and fill up one of the freight train cars.  If we repeated this process, using all the freight train cars, we could transport an entire stream intact to anywhere we wanted.  How did we manage this?

Picture our stream running in an overhead pipe with a gate on the pipe that opens up at identical intervals, releasing water.  Below the pipe is our train.  With each water release we fill up one of the cars of the train; the train then moves forward and the process repeats.  Using this method, the train can travel anywhere it needs to go.  What we’ve done is expertly divided up the water in the stream into containers (the train cars) which allows us to transport the water intact to a new destination.  Once we arrive all we need to do is reverse the process and we again have a flowing stream.  The water is identical, it’s in the same order it started with and it was never converted to something else for transport.

Now you start to understand how DoP does not convert Single-bit Audio to Multi-bit Audio, it simply breaks the continuous stream of bits in Single-bit Audio into identical groups, wraps an additional piece of info around it and fools the computer into thinking it’s actually something it is not.  The computer’s happy, the data is intact.

Remember that the bits are bits and the computer can’t tell one bit from another?  Once we add this header that is lying to the computer, falsely identifying the attached group of bits as PCM, the computer lets them through because it simply cannot tell the difference and doesn’t care (they pass through unmolested but the computer still doesn’t know what to do with the DSD bits and thus can’t play them without a program to help it understand them).

For the more technically minded here’s the details.  The Single-bit Audio stream is running at 2.822mHz (2,822,000 bits per second).  The DoP “converter” simply culls out 16 bits from the Single-bit stream and attaches an 8 bit header to it, then repeats that process over and over again.  The bits it is grabbing have no timing information associated with them; they are simply a group of exact ON/OFF bits in the exact order they started with.  16 audio bits, plus 8 header (information) bits equals 24 bits.  So a DoP packet is 24 bits long (8 info bits and 16 data bits).  Each of these newly minted packets collectively run at 176.4kHz.  Sound familiar?  Sure, you’ve heard of high resolution audio running at 176.4/24 bits?  Right.  That’s single rate DSD in DoP clothing.  You can do the math yourself: 16 x 176,400 equals 2,822,400 which is the exact sample rate of single rate DSD.  Simple eh?  And the other added 8 bits?  They account for the larger file size of DoP vs. native DSD (bigger by 1/3).

Here’s a picture of what that looks like.

USB_DSDviaPCM_1v0

The orange squares to the left represent the 8 information bits attached to the 16 bits of DSD to the right.  This is our freight car filled with Single-bit water (the wolf we’re trying to hide), and the 8 header bits provide the sheep’s clothing to trick the computer into believing the next set of bits are PCM, not DSD.

Lastly, one of the 8 information bits lets any interested party know the data is really DSD.  Thus, if the DoP data is put into a DAC that understands that information and can process it, all it needs to do is throw away the 8 bits of information data, connect all the 16 bit wide groups of DSD together and play the DSD stream perfectly.  No conversion process ever took place.

Now, let me go grab a cold glass of perfect water from the stream, uncontaminated from any dreadful impurities, despite the fact it arrived in a freight train with a wolf as engineer.

Asheville’s Home Theater and Audio specialist presents Cane Creek AV and Paul McGowan – PS Audio, Intl.

Cramming useless information

Nothing upset me more about school than being asked to cram useless unrelated information in my head.  Later in today’s post I will ask you to do just that.  If you fail, I will come after you with a ruler across the knuckles.

We’re in the middle of a set of posts helping us understand what DoP is.  DoP is DSD over PCM which, if you don’t understand what those Three Letter Acronyms stand for, makes no sense whatsoever.  To help wade through this mess I’ve replaced the acronym for the CD standard, PCM, with another term: Multi-bit Audio.  I’ve then replaced the SACD standard, DSD, with a second term, Single-bit Audio.

Using these easier terms, DoP is a means to send Single-bit Audio to a computer using the language of Multi-bit Audio.  And here’s the thing to take away from this understanding: when using DoP, Single-bit Audio is NOT converted to Multi-bit Audio.  That’s a popular misconception that we’re working on getting straightened out.  There is no conversion of Single-bit to Multi-bit when we use DoP.  Single-bit stays as Single-bit.

Before we get into the nuts and bolts of it I would ask you to put one fact inside your head (my ruler is itching to rap someone’s knuckles).  Put it in there, let it rattle around, even if it doesn’t make sense, and hopefully it’ll stick somewhere in the deep caverns for later use.  Yes, there’s a test later.  I know, it’s the same terrible request your teachers made of you in school.  ”Just stuff this fact in your head, despite the fact it makes no sense.”  Terrible way to teach someone.  The worst.  But it did give them the excuse to whack a few students around.

Inside a computer, bits are bits.  The bits of Single-bit Audio are the same as the bits in Multi-bit Audio.  Bits is bits.  Got it?  I promise, it’s all I will ask you to store.  Onward.

What does DSD look like?  How does it work?  It’s actually simple.  It is a system that uses bits to generate energy.  The greater the energy generated the higher the signal level; the lower the energy, the lower the signal level.  Have you ever seen a wind turbine that generates electricity, or a solar cell doing the same?  The stronger the wind, the brighter the light, the more energy generated.  In the case of DSD, more ON bits means more energy.  Fewer OFF bits, less energy.  Take a look at the following picture.

dsd_encoding_comparison

The blue rectangles represent ON bits and the white rectangles represent OFF bits (click the picture to expand it).  The red line is the resulting music in the form of a sine wave.  See how the red sine wave is going up whenever there’s a bunch of blue rectangles, and down when there’s lots of blank ones?  That’s it.  That’s all you need to know to understand Single-bit Audio (DSD).

Remember there are only two kinds of bits: ON and OFF.  An ON bit simply means there’s voltage present – just like you had connected a battery between the plus and minus terminals of your loudspeaker.  An OFF bit has no voltage present, it’s just an empty space, as if you removed the battery from your your loudspeaker.  Connect a battery across your loudspeaker and the driver will jump forward and move the air.  Remove the battery and the loudspeaker driver returns to its resting position.

If you were able to connect and disconnect your battery from the loudspeaker 2.8 million times a second, you’d probably get a free Guinness beer and a place in the record book of the same name.  But if you could ….. then you could duplicate what’s in the picture and sound would come out.  Music would be there if you followed the right pattern to match the music.

And that’s Single-bit Audio.  Now, don’t forget what I asked you to cram into your addled brain.  You’re going to need that important piece of useless information tomorrow.  Now, where’s that ruler of mine ……

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Yesterday’s post as well as a few earlier ones

Wading into it
DoP isn’t PCM
We are all reviewers
Beware of perfectionists
The truth of the matter

Asheville’s Home Theater and Audio specialist presents Cane Creek AV and Paul McGowan – PS Audio, Intl.

Wading into it

One of the more confusing aspects of digital audio is the two formats we have to deal with: PCM and DSD.  PCM stands for Pulse Code Modulation and DSD stands for Direct Stream Digital.  The first acronym, PCM, actually describes the format while the second acronym, DSD, is a marketing term invented by Sony and Phillips (DSD is more accurately titled PDM).

So, the two formats are PCM and PDM, both acronyms that describe to us engineering types what they do and how they do it.

I know, I know.  Several of you have written me begging that I explain “in english” and not use acronyms that confuse.  How about this as a compromise?  Would it help if I refer to PCM as simply Multi-Bit Audio, and DSD as Single-Bit Audio?  Let’s try that and see if that helps.  I’ll include the acronyms in parenthesis for a while to help clear the way.

Multi-Bit Audio (PCM) is the standard digital audio we all grew up with, starting with CDs introduced in 1982.  In later years Multi-Bit audio gained more bits and ran faster, creating what has become known as High-Resolution audio.  But it’s still Multi-Bit Audio.  CDs are Multi-Bit Audio with 16 bits and running at a speed of 44,000 times a second.  High Resolution audio has an added 8 bits for a total of 24 and a speed of anything more than 44,000 (although generally 88,000 would be considered minimum).  The basis for this format has been around for decades.

Single-Bit Audio (DSD or PDM) first came to our attention 17 years after the introduction of the Compact Disc, in 1999, in the form of the CD’s intended successor, the SACD (Super Audio Compact Disc).  SACD is another marketing term that describes a DVD disc running Single-Bit Audio.  Unlike Multi-Bit Audio, Single-Bit only has one bit but runs at a considerably faster speed, 2,800,000 times a second (standard DSD) or double that at 5,600,000 times a second (double DSD).  The basis for this format has been around for decades as well.

Multi-Bit Audio (PCM) is a type of code that is meaningless when you look at the code with your eye.  To decode and play it back you need a computer or a dedicated IC that can unravel the code before it gets turned into music.  Reasonably complicated.

Single-Bit Audio (DSD) actually looks like the music it is playing.  To decode and playback Single-Bit Audio all you need is a simple analog filter and out comes music.  Simple.

I found this graphic for you, showing what it takes to record music to each format with an A/D Converter.  It’s very simplified, but you get the idea.  Note how much more “stuff” is required to convert analog to PCM.

Tomorrow we wade in a little deeper.

Asheville’s Home Theater and Audio specialist presents Cane Creek AV and Paul McGowan – PS Audio, Intl.

DoP isn’t PCM

Ok, there’s just too many TLAs going around here (Three Letter Acronyms).  Engineers are obsessed with them because it makes for quicker communication of complex terms, and that makes sense, but what’s a poor Audiophile to do?

Recently I have been getting a lot of email questions about DoP (DSD over PCM) and most of the questions would suggest folks aren’t understanding what DoP is.  In fact, much of the mail I have been getting suggests folks think DoP is converting DSD to PCM (there’s those pesky TLAs again).  And the question that generally come from that partial misunderstanding is “I don’t want to convert pure DSD to PCM, it’ll change the way it sounds”.  Right.  Wrong.

Right that converting DSD to PCM changes the sound; and there’s a group of folks that find DSD downsampled to PCM sounds better than DSD (as illogical as that sounds).  I have personally heard examples of this “betterment” and while I too hear the improvements, I remain unconvinced this is anything but an anomaly we need to figure out.  And then there’s DirectStream that converts PCM to DSD and definitely sounds better for it.  It’s all so confusing.

Wrong that DoP has been converted to PCM and that it will sound different than DSD; it isn’t and doesn’t.

Tomorrow, let’s take our time and get to know DoP a little better and gain an understanding of how it works and what’s going on.

See you tomorrow.

Asheville’s Home Theater and Audio specialist presents Cane Creek AV and Paul McGowan – PS Audio, Intl.

We are all reviewers

For those interested in reading some first impressions of the DirectStream DAC you can go here and read on our forums.

Reviewing a new piece of equipment is a tough job.  I am glad the challenge isn’t mine to review and then publish.

I am in awe of professional audio reviewers that can change gears so quickly and give great unbiased reviews of each new piece of gear that comes their way and, even more impressive to me, remember how the others they’ve reviewed sounded and mentally compare them for their readers.  After writing those words my first reaction was that I certainly do not possess those skills.  But then it occurred to me I might be wrong.

I think we’re all reviewers.  No, we don’t write for magazines, no we don’t place our words on paper open for criticism and discussion each and every month, but in our own way we review everything that’s important to us.  And our reviews may matter more than what’s on paper, because our reviews affect our system choices.

Of course many of us read everything we can on a piece of gear that interests us.  We do the homework, learn what others think, build up enough knowledge to want to give it a try.  But then the ball’s in our court.  We are the ones reviewing the kit in our own environment.  We are the ones that “live or die” by our decisions because we choose what to keep and what to reject.  And most of us compare what we review to what we have in the system as well as what we remember older kit sounded like.

I think we’re all reviewers at heart.

Asheville’s Home Theater and Audio specialist presents Cane Creek AV and Paul McGowan – PS Audio, Intl.

Beware of perfectionists

I have officially thrown the towel in on the Class D output stage for the promised new reference amp.

In all honesty, it still sounds terrific and most people would absolutely love what it does and sounds like (I still do).  Why give up on Class D?  I just can’t get over the bandwidth restrictions inherent in the design, not after hearing what amps that go beyond 80kHz sound like.  Not after realizing how much more is actually on our discs through DirectStream.  I know it makes no sense.  CDs are inherently bandwidth limited to 20kHz, just like class D amps.  But play a CD on DirectStream through an amp with no bandwidth restrictions and you’ll never consider going back.  I certainly won’t.

The reference amp that we want to build has to be of the same caliber as the DirectStream DAC.  And that means it’s as close to the best in the world as we can achieve and stand alongside the few great amps of today without any regrets.

This will mark the third course correction so far, on this sea of change for the amp project, but with a speaker system as resolving as the IRS, a DAC as open and definitive as DirectStream, there can be no choice if perfection is the goal. And perfection IS the goal.

Maybe it’s just my age, but I don’t want to waste any more time on something that doesn’t offer the same level of musical discovery as DirectStream does. Not for the Reference design. Not for the main amp in Music Room One. Not for the amp in my home. Not for the amp I want to hang our hats on and suggest you do the same.

I am currently listening to a prototype of just such an amp.  It is a remarkable design from an old friend, someone I respect greatly and someone who has far better design chops than I.  Bascom King.

Yes it sets things back yet again.  But I am not going to be apologetic. I’ve beaten myself up enough over this already.  Our controller and GM have waved enough fingers in my face about the cost of changing directions so many times and now, to hire another outside designer …… start over ….. abandon most of what we’ve done.

Welcome to my world of being a perfectionist on a mission.