Tuesday, November 13, 2012

Picking Apart the Sound

Being a high-end audiophile means that you become critical of your system as time goes on. You hear things that other systems do and constantly compare what you hear to what yours does - or does not do. You either like or dislike the percieved difference.  When you hear something you like, you entertain the possibility of adding it to your system.

Sound like familiar behavior? I bet it does.  I am struggling with part of the band above 2,500 Hz in my Bozak speakers and although to others they sound fantastic, to me they sound off compared to the best systems in my sonic memory combined with what I know instruments really sound like.  I am studying the issue and trying to decide how to put my concerns to rest.  A week ago, after enough RTA measurements and enough analysis of the crossover network, I discovered a few things about the Bozak drivers that I overlooked in the past (yes, I too make mistakes).

The midrange driver has an aluminum dust cap along with its aluminum cone to improve dispersion and extend its bandwidth.  It is this aluminum domed dust cap that is causing my distress and influencing the sound of the tweeters in their operating bandwidth. Rudy Bozak decided to use a first-order Butterworth crossover network to minimize phase issues and rightfully so. But the rising sound pressure after the crossover point indicates a mechanical resonance beyond the prresumed supression point that needs to be tackled if my ears are to be pacified.

I have two multimeters that read capacitance but none that read inductance, the two components used in passive crossover networks.  So arriving in the mail last Friday was a new inductance meter and now I am set to redesign the Bozak network to suite my personal acoustic preferences. Hopefully over the next few months, I will succeed at this feat and tell you of my progress either good or bad, but with the holidays coinciding, the amount of time I have between getting my next book out and improving my system is VERY limited.


I have been pushing to get my next book out before Thanksgiving and I now realize that despite the fact that the first draft is written, the final product is still many weeks away. The new goal is for the pre-Christmas holiday and I am committed to making this happen. So I must take off a while from this blog and focus my attention on the book - a book about why we choose the things we do and how we can understand our patterns so we can make different choices.

There was a period in my life when Tony Robbins and other well-known professional coaches were my main pursuit and what I learned from them combined with my own insight is where this book has gone.  It will be written to those who are unfamiliar with the workings of the conscious mind and want to figure out how to change things from a fresh perspective without getting into that heavy psychiatry realm. I hopeit will be a winner since I believe that everyone could benefit from  understanding why we do the things we do.

Yours for higher fidelity,
Philip Rastocny


I do not use ads in this blog to help support my efforts. If you like what you are reading, please remember to reciprocate, My newest title is called Where, oh Where did the Star of Bethlehem Go? It’s an astronomer’s look at what this celestial object may have been, who the "Wise Men" were, and where they came from. Written in an investigative journalism style, it targets one star that has never been considered before and builds a solid case for its candidacy.

http://www.amazon.com/dp/B00QFIAC3G

My other titles include:

 Copyright © 2015 by Philip Rastocny. All rights reserved.

My Other UFO Encounter

I was in the USAF in 1969 stationed in Altus, Oklahoma.  I was an assistant crew chief working on C-5A Starlifters and going home to Wisconsin on leave over the Memorial Day weekend. I planned to paint my motorcycle and get together with friends and family, folks I had not seen for years.

Working the swing shift, I ate a quick breakfast at the mess hall and signed out on leave at 12:01AM on Saturday, May 31.  I took the front wheel off of my Honda 160, turned the seat sideways in my 1963 VW Beetle, took off the handle bars, and put the bike inside the car, back wheel in the back seat. It was a cozy ride and I was going to paint the bike once I got home. I drove north from Altus to I-40, east to Oklahoma City, northeast on I-44 to Tulsa, and then continuing on the I-44 toll road northeast toward St. Louis.

My black '63 bug was spartan: seats, steering wheel, and four tires, no radio.  With my Honda 160 keeping me company, the hum of the tires and the wind noise were the only audio companions I had for this 1,000 mile long trip across country. At about 4:00AM, I pulled into the toll booth northeast of Tulsa heading for the northeast corner of the state. The truckers would take US 66 avoiding the tolls so I had the road pretty much to myself at this time of the early morning. It was quiet and the constant hum of the tires at 70mph created their own one-note song.

Once passing the Vinita exit, the road ahead was barren and farms were huge and far apart.  The terrain started to change and the rolling foot hills of Missouri caused my little 1300cc engine to struggle going up the ever-steeper grades.  It was a moonless morning and I was looking forward to the dawn and getting off of this quiet toll road and back into heavier traffic. It had been about a half hour since I passed anyone and I was speeding, well the best I could given the size of the engine and the load it carried.

Passing a hill on my left, I noticed what appeared to me as a helicopter swoop around from its far side heading toward me.  I believed that I had been clocked on radar and so I immediately slowed down expecting that over the next hill would be a police car waving me over to the shoulder.  My mind searched for a reasonable explanation about why I was speeding and decided as I crested the hill just to tell the truth and see if they would let a G.I. off with a warning. Over the hill I drove and there was no one there.

Hmmmm...next hill for sure.  Nope. No one.  Things were not making sense so I looked back at the helicopter who was drafting me to my left and just behind me.  I glanced over and saw it flying about 30 feet off the deck and just beyond the fence that kept the cows from wandering onto the highway.  This was strange.  There was something else that did not add up and as I strained to see who was inside the blunt nosed craft, I saw two figures behind the windshield illuminated from the green  glow of the instrument lights.  One pointed at me and then I realized what was wrong.  There was no engine or rotor noise.

For the first time in my life, I understood what the feeling of the word panic meant.  Here I was alone and in a  deserted part of the state being drafted by a UFO.  I paid more attention to the structure of this craft since I understood that it was not of this world.  It was cigar shaped with a fuselage that resembled a C-47 minus the wings.  Totally so black that I had to strain to see the shape as it moved between the background and my eyes.  Except for the cockpit glow and flashing red light at the rear, I could not believe what my eyes were telling me.  "There has to be engine noise" I said to myself so I put in the clutch on my VW, rolled down the window, and stuck out my head. The only thing I heard was the wind in my ears, the engine idling, and the tires humming on the pavement. Yup, this was a UFO.

There are two stories that go on from here: the one I believed right after the incident and the one I recalled after years of nightmares.  The one I believed to have happened was that I drove off and eventually arrived at the distant toll gate sometime after dawn.  What I recalled after time was a memory of two huge landing lights coming straight at me like a truck on my side of the highway but MUCH brighter than the feeble headlights on any 18 wheeler. I recall this too and for those of you who have ever owned a VW bug you will know what I am talking about.  There is a method to exiting a VW that is a bit different from most other cars. You put your left hand on the bottom door jam, and from a stiff-arm you roll yourself out of the car.  For an instant, you see the ground just outside just before your left foot touches the ground and you finish the roll out the door. What I remember seeing was LONG STRAIGHT SHADOWS FROM THE SAND ON THE SHOULDER OF THE ROAD LEADING TOWARD THE REAR OF MY CAR.

What I remembered is that I had stopped the car to avoid a collision with the oncoming "trucker," pulled onto the shoulder, and turned off the car engine. The thing about the shadows I remember most was the razor sharpness of the edges. Normal tungsten or halogen lights of that time did not make this distinct sharp shadows and that is what I recalled also as being very different. And there was only one shadow, not two so that meant one bright light was in front of the car.

I then recall floating over the grass with my arms in two companions heading for the field to the right of the parked car.  The rest is very unclear like looking for something in at sea in an ocean fog. I won't bother with these speculations of what I do not clearly remember but know that I lost time.  It wasn't much time, just about an hour, but I lost time. I should have pulled into the toll booth about sunrise but I was there well after dawn. I do not remember everything that happened but I really do not want to either.

So that's the story and that's the truth.  Being in the military, I know what planes look like. Having been blessed with high-end ears, I know what helicopters and planes sound like. Being a keen observer, I know the difference between normal and unusual shadows. Being into astronomy since high school, I intimately understand the relationships between the planets, stars, and moon in the night sky.  Being a left-brained person, I know what is illogical and logical.  This was a close encounter just like many of those similar incidents claimed by countless others. No words were spoken, I have no clear recollection of who stopped me or what their craft looked like, nor do I recall getting back into my car and driving off. The only thing I clearly remember after the encounter is the toll booth and briefly chatting with the attendant.

It took years for me to share this with anyone. I believed initially that I was imagining things but the nightmares continued and I started confiding in my wife. The first friend I told was Burt Cossey as we were waiting to see the Star Wars movie. I told him the tale just before the previews started and before he could respond the preview of "Close Encounters" came on. That blew both of us away and made the telling even more profound.

Today you've read my tale. I hope others who have had similar encounters feel a bit more comfortable with their experience. The universe is just way too big to believe that we are the only ones here. Our intelligence as great as it is feigns terribly against what remains to be understood. Creatures of superior intellect are all around us and some choose to visit like we choose to go to the beach or teens choose to drive the strip on Saturday night.  We share much with these visitors in our "nature" and have the same curiosities and adventurous attitude.

Yours for higher fidelity,
Philip Rastocny


I do not use ads in this blog to help support my efforts. If you like what you are reading, please remember to reciprocate, My newest title is called Where, oh Where did the Star of Bethlehem Go? It’s an astronomer’s look at what this celestial object may have been, who the "Wise Men" were, and where they came from. Written in an investigative journalism style, it targets one star that has never been considered before and builds a solid case for its candidacy.

http://www.amazon.com/dp/B00QFIAC3G

My other titles include:
Copyright © 2015 by Philip Rastocny. All rights reserved.

Friday, November 2, 2012

When to Change Tubes

Many of you know that I am a tube fan and own a Dared MC-7P preamp. After performing several rounds of modifications by pulling out ground loops, changing caps, correcting RIAA errors, replacing the volume potentiometer, and swapping out those cheap tubes, I have grown to enjoy the musicality of this preamp despite its modest initial price. It is light, airy, detailed, silent, and dynamic providing clarity and timbre only the finest transistor designs can match.



But being a tube preamp, once I swap out tubes the clock starts running; one day I will need to replace them.  But the better question would be: when?  NOS tubes take about a week of use to settle in and start to sound the way they will for the next several months (maybe even a bit over a year) and with the price of a good Mullard 12AX7 going from $50-$400 a piece, the timing for replacement can mean the difference between making a wise investment and making a bad decision.

The problem with tube aging is that it is a gradual process and can creep up on you as you become desensitized to its impact.  In other words it is sort of like a frog: toss a frog in boiling watter and it will immediately jump out but put it in cool water and slowly bring it to boil and it will die.  The fact that you listen to your gear every day makes you not notice these symptoms but one day you will become alerted to their telltale degraded signs.

It is interesting to note that tubes that should be changed may still measure good on a tube tester (so what else is new?).  So here are the top 3 hints that let you now from subjective listening when it may be time to swap out those little room heaters (aside from a complete failure meaning that it stopped working entirely). 
  1. Pops, tinks, and other weird spontaneous noise.  This is the number one reason to change a right now tube.  Issues of injected noise or spurious spikes are obvious signs of having to say goodbye to what may be an old and well appreciated friend.  Tubes that age to this point can actually be dangerous to the amp and speakers and should be replaced immediately.
  2. Edginess and sibilance.  This is a deceptive condition where on the one hand the tube starts to emphasize one region of the audio band you may find appealing but believe me, the tube is on its way out.  This is the second most important reason to change a tube since what is hiding behind this symptom can also prove to be disastrous to the rest of your gear.  This is usually an indication that for some reason the tube is breaking into spurious oscillation and with time this symptom will only get worse.  Do yourself a favor: change it now.
  3. Hiss.  When the noise floor starts to creep up causing silent passages to sound like you are listening to music in a  wind storm, the tube is going bad.  This symptom is the most gradual and can be the least noticeable from all of the rest.  Noise can sometimes be discovered on a tester  indicating a "weak" tube.
I recently swapped out the two gain stages in my Dared after noticing a sibilance issue and sure enough both tubes were going south.  I have been listening to the new ones for about two days now and I can hear them mellowing to that lush full body revealing resonances in sound boards, the character of drum membranes, and nuances in woodwind reeds.  Front-to-back imaging at first play took a huge step backwards getting very flat and narrow, but that too is improving as things stabilize.

By next week, things should get back to that pristine sound I enjoy so well.  During this time, I will enjoy the transition period since it is much like swapping out a piece of gear with a new one every day.  After swapping out tubes, you too will hear this mellowing process evolve.  Be patient and allow your new tubes to burn in.  Swapping to a new tube always takes time for you to appreciate what it can do to improve your listening pleasure.


There are other reasons you should swap out your tubes (like quality upgrades and other failure modes), but these are my top three reasons once you settle into a tube choice for that component.  And a note of advice: when you find a tube that you like, buy spares of that exact same kind.  Even new tubes can suffer from infant mortality and last only a few weeks or months.  Each time I buy mine, I always "stock up" on what I consider my current selection for the state of the system.

Yours for higher fidelity,
Philip Rastocny


I do not use ads in this blog to help support my efforts. If you like what you are reading, please remember to reciprocate, My newest title is called Where, oh Where did the Star of Bethlehem Go? It’s an astronomer’s look at what this celestial object may have been, who the "Wise Men" were, and where they came from. Written in an investigative journalism style, it targets one star that has never been considered before and builds a solid case for its candidacy.

http://www.amazon.com/dp/B00QFIAC3G

My other titles include:
Copyright © 2015 by Philip Rastocny. All rights reserved.

Thursday, November 1, 2012

DACs...DACs...DACS

It's been a mere 28 years since the introduction of the compact disk and after all of this time one would presume that the bugs have been worked out of the standard. But such is not the case, although it looks like the engineers are getting closer and actually listening to what they are building and at least understanding what the problems are.

Two new advances have appeared that - from the design perspectives - are finally addressing issues surrounding the D-A conversion anti-aliasing filtering issues. The Ayre MP series (see http://www.ayre.com/pdf/Ayre_MP_White_Paper.pdf) describes clearly what one of these issues is regarding phase shift and ringing and what they plan to do about it.  The Resonance Labs Invicta (see http://resonessencelabs.com/wp-content/uploads/2012/05/InvictaMeasNotes.pdf) describes another issue regarding head room. Hopefully, I will be able to audition these two units side-by-side at an upcoming audio club meeting and report about their audible differences and contributions.

It's too bad that someone has not incorporated both concerns into one unit, but hey, that's what the high end is all about, right? Progress, not perfection!

Over these 28 years, we have come a long way from the first generation brick-wall anti-aliasing filters designed in the original generation CD players. Moving from fingernails on the blackboard to tolerable sound is a huge advance and one that deserves recognition. Hopefully soon, someone will design an A-A filter that addresses these and other unresolved issues, but I believe the recording sampling rate standard is now the big bottleneck (most agree that 16-44.1 was a mistake). With most artists and studios embracing 24-192 and better standards, one day we should see a new generation of players and software introduced as the state of the art spirals upward.

Until then, I'll still have to spin my old vinyl to hear how far digital has to go.

Yours for higher fidelity,
Philip Rastocny


I do not use ads in this blog to help support my efforts. If you like what you are reading, please remember to reciprocate, My newest title is called Where, oh Where did the Star of Bethlehem Go? It’s an astronomer’s look at what this celestial object may have been, who the "Wise Men" were, and where they came from. Written in an investigative journalism style, it targets one star that has never been considered before and builds a solid case for its candidacy.

http://www.amazon.com/dp/B00QFIAC3G

My other titles include:
Copyright © 2015 by Philip Rastocny. All rights reserved.