How do we know if it is real?

In the last few posts we have been covering a lot of ground centering around the idea that recordings properly made can sound quite live on a good system.  Even older recordings from the 1950′s and 60′s still sound remarkably live despite the poor recording equipment they had during the day.

How is it that we know when something we hear on our system is acceptably real or when we should instead mentally catalog it as something other than an attempt at live?  The recording engineer might tell you that it was the hall ambience either captured by the main microphones or skillfully added in from another set.  But that’s not the answer I am looking for.  I want to dig a little deeper into our actual ear/brain mechanisms that verify this information for us.

There’s been a lot of advanced research as of late into how we understand things.  Just what does it mean to understand and how do we do it?  Visual and auditory events are understood by us and by our fellow creatures that have the ability to see and hear.  We understand that when we hear a dog barking in close proximity, we need to turn around and see the dog – determine if he is a threat or just a nuisance – and then take action or disregard.  A cat or another dog does exactly the same thing with exactly the same skill sets in their brains.  To that extent we are no different.

Studies show quite clearly a couple of interesting things about this: we utilize the exact same areas of the brain for both action and analysis and we compare stored memories of both as our reference guides.  This is important to understand because it’s how we make such amazingly accurate comparisons of what we hear and see – using the same brain path for both recording and playback.

Imagine reaching out with your hand and touching a hot stove – instantly pulling the hand back and being in pain.  You need only do that once and the memory of the visual experience as well as the results are stored in your brain.  The next time you consider performing the same action that stored memory is played back through the exact same part of the brain it went through to perform the action in the same place – only this time it’s at a lower level – and does not cause your hand to move.  The action is compared to the results and you make the correct decision you don’t want to do that again.

Advanced animals have exactly the same facilities as do we but then we diverge into greater functionality that no animals possess: imagination.

Imagination is a unique human ability to combine stored memories together and create new ones that have never existed.  It is this unique ability that allows us to imagine what a live oboe should sound like in our listening room by “playing it back” in our brains, using the exact same path we processed the information with originally.  We can then imagine how this must sound in our room despite the fact no live oboe player has ever graced our listening room.

It is the ultimate A/B tool because we can imagine what a group of performers should sound like in our room and then compare that to what we’re actually hearing.

This ability is what generates expectations – if we’re looking for a live sound we can imagine what that might sound like and set our expectations up to know, in advance, what to expect.

We’ll delve more into this tomorrow.  If you’re interested in any reading on this subject I would recommend Louder than words: the new science of how the mind makes meaning.


Paul McGowan – PS Audio, Intl.

Autobahn

Continuing on the subject of separation and vinyl, I have been working diligently on voicing and polishing our new phono preamplifier, the NuWave Phono Converter.  I don’t want this blog to turn into a sales thing so I am not going to go into any detail about the new product – however, I do want to relay an observation I made this evening.

I have a great vinyl copy of Kraftwerk’s original Autobahn and occasionally I pull it out to gauge the difference between our reference and a newer design; this evening I did that.  On the reference GCPH phono preamplifier the opening synthesizer licks sound, well, like a synthesizer and frankly I never paid a lot of attention to them.  But playing that same track (track 2) on the new product I was immediately aware (for the first time) that the main riff was being made from the low pass filter of a Moog – as opposed to any other type of synth – so distinct the sound of this filter.  I had never noticed that before.

Played through the reference phono preamp it was just “there” – could have been from an ARP or any number of synths – but on the new device it was clearly from a Moog.

I happen to know the sound of the Moog voltage controlled filter very well and I’ll tell you why.  My very good friend, musician and reviewer Dan Schwartz has a big Moog and I have always been fascinated with these instruments.  I built synthesizers in the early days before PS Audio and had a great fondness for the original Bob Moog designs.  I was trying to design my own filter but could never get the sound to be big and “fat” like the Moog.  So Dan sent me a Moog Low Pass filter (VCF) from this device to copy and figure out.

Even on lowly headphones, the sound of the Moog VCF was always big and fat and distinctive and, darn it, far better than my design of a VCF.  Moog filters were completely discrete, based on a cascaded capacitor ladder and diff pair – while mine were always based on a chip.

I bring all this to your attention partly as a reminiscence, but also because of my utter surprise when listening to a new design that something so distinct comes into the forefront in such an unexpected way.

So sure of this sound I went and looked up the group’s instruments on Google and sure enough, there was the Mini Moog right on top of the heap – and the Mini Moog uses the identical filter as does Dan’s big Moog.

I was quite taken with this development – as you can probably tell.


Paul McGowan – PS Audio, Intl.

Separation

I have been listening to a lot of vinyl as of late – we’re getting ready to launch a new phono preamp – and the evaluation process if ongoing.

Unfortunately I do not have the big reference system setup yet so I am relegated to sound room number 2, which isn’t as good.   To make matters worse there’s a big hole in the ceiling with a ladder poking through it to access the wiring for the big room, as these two music rooms sit side-by-side.  There’s a lot of noise from the servers next door coming through.

But despite all the background noise and people coming in and out while I am trying to listen, there is something I wanted to mention: the separation of sounds.  On only the very best systems does one hear the separation of sounds and it’s one of the benchmarks I use to evaluate equipment – particularly vinyl.

On most systems the noise of the recording, the surface noise of the record, the mic techniques of the engineer, the playing of the instruments are homogenous – they  blend together as one presentation – pretty much what you’d expect.  But on a handful of systems and electronics these elements become detached from the whole and separate themselves into separate entities.

What I am describing is hard to imagine if you’ve never heard it – and I am struggling now to hear it on this second rate system – but having trained my “ear” to look for it the task is a bit easier and can be accomplished.

Imagine listening to a vinyl recording of something and noticing, for the first time, that the surface noise of the album appears separate and distinct from the music.  If this were happening it would give you the advantage of being able to listen into that surface noise and evaluate its quality – or ignore it completely and just focus on the music.  In the same process we could switch our attention to the recording itself and focus on just those qualities.  Separation has many advantages if you can achieve it.

Most of you have probably heard something like this phenomena before with a digital or vinyl based system: separation of instruments in the soundstage presentation.  When people move from a good/mediocre DAC to an excellent one perhaps the first attribute they notice is this increased separation of the players in the orchestra or group.  The same can be said when you get power conditioning right – you get a greater sense of separation.

The ultimate separation happens when not just the individual instruments get untangled, but the other elements in the recording as well.

Paul McGowan – PS Audio, Intl.

Seagulls

Yesterday’s post on the Golden Age of Recordings sparked a fair number of emails and one them asked me “what is live”?  Is it sticking your head into the piano?  After all, that’s live if you were so inclined.  Another complained of too much detail being focused on by Audiophiles “Wow…did you hear that pin drop…..you can hear that seagull fart at 32 seconds into the track”.  They are all great questions.

I think some of this has to do with expectations.  When I listen to a modern Audiophile oriented recording like a Patricia Barber, my expectations are for a close mic experience: big sound, powering the room imaging, bigger than life – as if I were sitting a few feet from the band and if I wanted to really experience the power of the musicians.  She never sounds live and my guess is she’s not trying to.  Yet, I probably have every Patricia Barber ever released because that’s the experience I am looking for when the mood strikes.

Years ago I used to get the same experience from the Sheffield Direct-to-Disc recordings of Lincoln Mayorga – which were in fact recorded live in the studio and when I say “live” there’s not much more “live” than a direct-to-disc.  It just doesn’t SOUND live – but they were exciting, dynamic and impressive.

I don’t want to lead anyone astray with my own personal preferences of older recordings that capture both the hall and the orchestra or performer – because they are in fact my own preferences, shared by some, not by all.  But those characteristics of live have become ever more important to me personally and are a big help in evaluating equipment and just enjoying the system.

In the end I think we all have our expectations of what something SHOULD sound like and we strive to gather as many recordings that suit those needs as we can – certainly that’s true in my case.

Paul McGowan – PS Audio, Intl.

Golden age of recordings

Mark Waldrup of AIX Records, Cookie Marenco of Blue Coast, Keith Johnson of Reference, Bruce Leek of Studio in the Forest, Peter McGrath of Wilson, Tod Garfinkle of M and A and John Atkinson of Stereophile are among a handful of excellent recordists who care that music sounds as if it were live in your room.  There are many, many more but these individuals and their brethren have a closer eye on sound quality leaning towards live than most recordists – yet have less access to the big name musical talents in the world.

But it wasn’t always this way.  Many of us have treasured LP’s and CD’s of years past where big name artists were recorded beautifully in a live sounding space.  Most of the old Living Presence RCA’s, the Mercuries, Deccas and labels of the past went to great trouble to capture the best musicians of the day in the best recording venues possible.  Why does that not seem so today?

My guess is that we’ve gone through a bit of a paradigm shift of goals.  In the 1950′s and 60′s, when the aforementioned labels were at their height, high fidelity recording was new – stereo Long Play records were just invented – and most music was heard live.  My guess is that the new and struggling record label industry of the time did their level best to prove to folks that they could capture, preserve and reproduce that which most music lovers were used to – live performances.

So despite poorer microphones, recording equipment and reproduction kit, the “golden age” of recordings, so treasured even today, lives on as an example of what proper microphone placement can really achieve.

Now that the opposite has happened, music is listened to more often through a recorded media rather than live, the mainstream recordists and labels seem to have lost their focus on the reproduction of live – in place of reproducing what many engineers and artists consider “the better”.

The same can be said for television – where TV affords us a view unobtainable from being at an event – so it is “better”.  We’ve even augmented our live music events with TV so we can enjoy both the live event and the “better” TV view.

Methinks this needs some thought and discussion.

Paul McGowan – PS Audio, Intl.

Building a music room

Part 5 of of our video series on Building a Music Room has been uploaded on YouTube and available for you to watch here.  We cover how we calculate the Q and the depth of the Resonator and show you how we fixed the room’s slap echo with some drywall and mud.  We also discuss our decision to go with Mogami wire.  I hope you’re enjoying the series as we get closer to finishing the room and installing the new speakers.

Thanks to the powers that be at YouTube we’ve been allowed to publish the entire 60 minute long video Coal to Coltrane for you to watch.  This hour long journey explains what electricity is, how it was discovered, manipulated, generated and we even cover the famous War of the Currents – the epic battle between two genius: Thomas Edison and Nikola Tesla.  We have interviews with TAS Editor Robert Harley, reviewers Wes Philips, Steven Stone, Michael Fremer (who is at his funniest in this film), recordist Bruce Leek, the director of the Boulder Symphony Orchestra and our old friend Mark Schifter.  It’s quite a fun ride for an hour and hopefully you’ll enjoy sharing it with your friends and family.

Our discussions on microphones have sparked a great deal of comments and tomorrow I want to look at how microphones are used to make recordings and why so many of us treasure the many decades old recordings when their equipment was so out of date and not up to our standards.

We’ll then take a look at a few of the great recordists of today and what kind of work they’re doing.


Paul McGowan – PS Audio, Intl.

Leveraging sound

Most of us have an idea how our ear works.  We have an eardrum, which is a diaphragm or membrane, and sound pressure moves this membrane back and forth stimulating nerves and generating electrical signals the brain can recognize as sound.  Our brains act as recorders storing the sounds we hear for later comparison and reference.  We even have the ability to reproduce those recorded sounds either through a mechanical device like a musical instrument or our own instrument – our voices – witness a singer hearing a song for the first time and then repeating it.

The same basic process happens in a microphone where we have a diaphragm that moves back and forth in response to sound pressure and a mechanism to convert that movement to electrical signals.  In both cases, the eardrum and the microphone use a membrane as a lever to connect and stimulate the mechanisms that convert movement to electricity.

The first microphones ever built did not have this conversion process.  Instead, the membrane/lever was used to move a needle that cut mechanical representations into a sheet of wax or foil and the playback process was an exact and reverse duplicate of the recording method.  There was nothing electrical involved with the old Gramophones.

The chance for high fidelity recordings started only when inventors got closer to how our ears actually work with the membrane/lever/electrical conversion process – which is still used today.


Paul McGowan – PS Audio, Intl.

Microphones like lenses

The two parts to any sound reproduction chain that are imperfect – in fact not very close to perfect at all – are the inputs and outputs.  Everything else in between the input microphone and the output loudspeaker is relatively perfect when compared to the inaccuracies of the these two primary transducers.

The microphone, which is the first part of the reproduction chain, is perhaps the most difficult piece for anyone interested in high-end audio to manage or deal with.  We can choose which loudspeakers we want to listen to, which amplification chain and even what type of recording media we prefer, but our only discretionary means of selecting the best sounding microphone is pretty much limited to our choice of recordings.  Recording engineers make microphone choices for us and thus our only choice in the matter is to hope they made a good one – one that agrees with our view of what sounds acceptable when it comes to believability.

Recording engineers have a wide variety of microphone sounds and types to choose from: those that work best on vocals, or cymbals, ambient room reflections, close proximity, distant proximity, different patterns of sound and so on.  And each microphone type has its following among the many to where truly the skill of the recordist comes down to microphone type, placement and connected equipment used to amplify and record.

Even artists may have a special microphone that gives them the “sound” they want people to hear them through.

Considering all the different colorations of various microphones and how they are used, we could pretty accurately consider these mechanical devices like lenses and filters used by photographers.  No two dimensional photograph actually looks real – we understand that they are merely representations of what we see – and photographers have a small arsenal of lenses and filters that help them bring their viewers closer to what they want one to see.  In the same way, recording engineers use microphone choices to bring the listener closer to what the recordist is hearing and wants his audience to hear.

Accepting that microphones are not accurate and perfect transducers of live events, just as photographs are not perfect three dimensional representations of what we see, we’ll move on to describing how these devices work.

Paul McGowan – PS Audio, Intl.

Microphones

If we mentally step back from focusing on just the reproduction chain (your stereo system) and look at the entire process of capturing and playing back the sound of live musicians playing in a room, we can see it as pipe with an input and and output.  On the one end of the pipe we have a microphone and on the other end a loudspeaker.  In between we have an incredible array of “stuff” that amplifies, manages, records and plays back.

I thought it might be interesting to ruminate on the very first thing music encounters when it enters this pipe; the microphone.

Microphones are the opposite of loudspeakers – put sound pressure into them and out comes electricity.  If you put a copy of that same electricity into a loudspeaker out comes sound pressure.  Simple.

We concern ourselves with everything in between these two to make sure the original sound pressure is preserved accurately – or so that’s what we tell ourselves.  Actually the truth is closer to this: we do everything we can to faithfully reproduce the OUTPUT of the microphone and that’s perhaps the best we can hope for.  The distinction between the two is important because as hard as we might work to reproduce the sound of live music playing in acoustic space, we haven’t any real control over that.  All we can hope to do is reproduce what the microphone interpreted and maintain ITS sound.

Microphones are every bit as colored as loudspeakers.  Those in the know can easily identify the sound of certain microphones without ever knowing what they were – in the same way a good wine enthusiast can smell and taste wine and tell you what it is, where it came from and sometimes even what year it was bottled.

In fact, sticking with our wine analogy, great sounding microphones are prized by collectors and demand high prices – just as great wines are collected and stored.  The point is they have a sound to them: a cello captured by a microphone sounds noticeably different than if you were to place your ear in the same position as the microphone under scrutiny – a lot different.

Let’s delve into these mechanical beasts tomorrow.

Paul McGowan – PS Audio, Intl.

Serving it up

If the high-end designer really wants thunderous bass response in his equipment, a servo is perhaps the very best way to go.  You’ve probably heard of servo bass before but servo controlling the low end response of an amplifier is a technique perhaps buried in the details of some designs and rarely implemented in most.

If you’ll remember from a few days ago I suggested that in order to make direct coupling possible – eliminating any of the components in the signal path – we’d have to rolloff the amplifier’s bass response.  We usually do this with our old friend the capacitor, but that technique has major limitations – you are rather limited in how low the amplifier can go – and the lower the better if you want stunning bass.  Using a DC servo, instead of a capacitor, is the answer.

A DC servo is an electronic circuit that magnifies the effect of a capacitor by several magnitudes, allowing designers to set the low frequency rolloff of their circuits at well below 1Hz.  For example, in our circuits we roll off at about 1/10th of a Hertz using a servo.

Why does this matter if we have amplifier response below one cycle, vs. a capacitor set 10 or 100 times higher?  Simply put the lower you go the less you hear its impact.  Using a capacitor to rolloff the bass has phase shift damage into the audible regions of the music and, even if you’re able to minimize this shift, the capacitor still intrudes into the music.

I’ve run multiple tests over the years demonstrating the difference between servo controlled bass and capacitor controlled bass and I am here to tell you there’s simply no comparison between the two.  Servo bass is rock solid, with no end to where it seems to go – while capacitor rolled bass certainly goes deep but seems to be missing something.  It also loses pacing and rhythm compared to the servo.

So the next time you’re looking for no-compromise bass, look towards equipment with servos – you’ll be well served.