Quote:
Recently I was introduced to a rather large Naim system at a home concert. The owner of the home/system introduced me to the Naim rep who happened to be attending who kindly gave me the tour explaining all the design attributes of the line. Now most of it made sense except for the claim as to enhanced timing resolution. He stated that equipment of lessor caliber can have timing accuracies, changing the timing relationships between the different instruments in a recording. I asked if he was really saying that a piece of audio gear was moving the instruments relative to an other other and he said "yes." I've been an Audio Professional for over 20 years and I have never heard this effect. What's any body think about this?

Yup, it's true.

I heard a system once that mixed some Japanese gear with some stuff made in China, and those pieces couldn't agree on anything.

We tried playing "Kind of Blue," and that time-shifting phenomenon was so bad that
Miles didn't start to play "So What" until halfway through "Freddie the Freeloader."

I agree that some signal smearing can happen with crap gear, but "moving performers relative to one another" is quite a sales story!

Imagine, though, how smart the gear must be to be able to identify one musician and move only him/her in time. That's Alfred Einstein range smartness.

I don't know if one would call it timing, but I have heard different audio systems place instruments in different locations relative to other instruments, at the same venue. So obviously something is different between systems. One or both were distorting.

English audiophiles rely on this concept heavily. I don't buy it for a moment. However, some equipment does make you tap your feet; others, don't.

My belief is that this is a way of describing this characteristic - whatever makes it so.

Here's how I would describe PRaT to my clients relative to the "timing" part in particular. If you understand timing as it affects the listening enjoyment of or involvement in music, you'll easily understand how Pace and Rhythm are affected by timing cues and how getting timing right makes all the difference in the final product.

If you've ever played in a band or heard a band practicing to refine the performance of one piece of music, you'll understand the lack of, or improvement in, timing between various players as each indivdual performer becomes more confident with their own portion within the ensemble. From first rehearsal to final performance the "timing" between players will coalesce from the first run through where each performer is playing their own little bit with little attention paid to the other performers and then slowing moving into one harmonious whole where each performer is playing with and off the other performers. The difference in "timing" errors between first rehearsal and final performance is quite noticeable when dealing with less skilled musicians such as a high school band or between a high school band and more highly skilled, highly paid studio musicians. If you listen to several pieces of equipment, you'll easily hear this same difference in timing as it occurs through various audio components. Some gear gives the impression the performers should have had a few more run throughs to get the feel of how each player will approach a piece of music. On the other hand some equipment gives the music the correct "timing" which allows the pace and rhythm of the performance to emerge intact. I think what the Naim rep might have been intending was to point out this shift in the performers' relative timing against the whole rather than a placement issue within the soundstage, though NAIM doesn't exactly stage like most other gear either.

I think the Naim Rep just created a new term "Personal Jitter". I think I saw the late actor, Don Knotts, have this effect.

In baseball, as a batter this same effect is call a strike out. In the field it is called an error.

The next thing we'll hear is certain wire favoring saxophones over pianos. Or is it violins over cellos?

Whoops, my nurses are here. Time for some more "treatments". That AC adaptor cord for my Grados sure gives me a buzz! Yhow!!!!

The guy who was giving you that line of baloney was full of bovine excrement.

One place where time domain errors are a big issue is use of multiple microphones. If, for example, you put a spot microphone in the brass section of an orchestra, and then at a later time during mixing of tape tracks in the studio, that signal is mixed with the information from another microphone at another location in the hall, the same information will have arrived at the two microphones at different times. This can cause an overlap in the sound from different instruments, smearing the sound...making it indistinct in the final mix of the two tracks recorded from the two microphones.

This is one of the arguments against multimiking, and many would argue that such early recordings as RCA "Living Stereo" and Mercury sound excellent partly because they only used two microphones (or 3 in some cases, but equidistant from the orchestra), and there was no other multimilking of any kind.

When recording small jazz combos or similar mixes in the studio, it is common practice to prevent this "bleed" from one mike to the other by isolating each instrument from the others by soundproof partitions, and the musicians only hear the sound from the other instruments on headphones while performing. each instrument is isolated and has its own mike, recorded to its own track, and the final mix is done later.

Absolutement!!!!!

You know how you can tell if a salesman is lying? His lips are moving!

I've been in sales for 30+ years. It is easy to differentiate yourself if you tell the truth. It has worked for me up until 6 years ago. That is another story for another time.

Quote:
Here's how I would describe PRaT to my clients... some equipment gives the music the correct "timing" which allows the pace and rhythm of the performance to emerge intact.

Your explanation is superb, but do you really think that different pieces of equipment actually reproduce music with the timings between players and between beats so off that it doesn't sound as good as other equipment? Naim equipment is nice and sounds good, but I don't accept that it actually reproduces timing better.

As has been suggested, most multi-mic'd recordings exhibit timing problems for obvious reasons. Many of the collaboration discs which have become popular suffer from no two performers being on the same continent while adding their parts to the project. Everything is placed "together" in post production and seldom does it have the sound of performers listening to one another. By way of contrast, go back to some early mono Elvis with him and the Jordanaires playing together in one room at Sun studios into two microphones. The timing cues are exceptional in this case as everyone listens to the other to get their footing. Early Miles Davis or Bill Evans are other examples to listen to for correct timing. The magic of 78's is the lack of production work involved in getting the music to the disc. Everyone played and if they screwed up, they started again. Listen to a Chesky classical reissue compared to a DG recording from the 1980's to find more clear examples of timing differences in the source material.

I'm not sure what would cause you to think passing the signal through various components should not result in timing cues to be off. Certainly early and contemporary cheap digital suffers from timing problems usually associated with jitter and clock values. The rather sterile feeling of many digital players results largely from timing problems between what's on the disc and what exits the machine. In the studio flangers and chorusers intentionally shift time. Why anyone would want to introduce a box which touts "screws up timing" I don't know, so possibly that is why no one has introduced such a component to consumer audio (unless you count Bob Carver's many forays into timing mismanagement). But surely the many small deviations from absolute phase introduced by numerous signal paths and processing in the recording/production/reproduction chain will affect timing or at least our perception of its existence.

More likely to cause audible phase problems in home audio gear are the numerous capacitors and inductors employed in many components. Each piece pushes the absolute phase a bit further out of kilter until the music is finally fractured. Any negative feedback will introduce phase problems which will result in timing issues. Gain stages that suffer from T.I.M. will have the same problems. Think of the audible problems of most home theater receivers compared to a simple S.E.T. power amplifier. So, you should see there are multiple reasons for timing cues to go askew. However, if you've never listened with an ear that suddenly says the timing is screwed up, then possibly you haven't noticed the problem. This would be somewhat like people who are simply unaware of the problems inherent to bipolar transistors, FET's or valves. They listen to a certain device unaware of the problems that literally leap out at others who find the issues annoying.

After having timing pointed out to you by the NAIM rep, I would guess you will be more aware of timing problems in other components. Assuming you heard what the rep was trying to exhibit. Did you agree that timing was exceptional through the NAIM or did you not feel it any different than, say, a Krell? Were you generally aware of timing problems in components previous to hearing the NAIM demo? Do you place any importance on PRaT when judging equipment?

Well put and I, for one, can allow for the possibility - I just have trouble accepting that a single piece of reproduction equipment can do this so much better than other reasonably designed equipment that we would hear a difference. But it is better for me at this point to keep an opn mind and to go do so listening.

For some listeners timing is not a big deal. And, often it takes hearing the difference one time to notice when it is incorrect in other units. Multi-driver speakers are generally the worst offenders of timing cues as the crossovers tend to destroy phase relationships. As a rule, each higher order of filter produces another 90 degree shift in relative phase. So, a first order filter will place the crossed drivers 90 degrees out of phase from each other and many designers will argue most listeners can ignore this amount of phase shift in music material. A second order filter will result in 180 degrees of shift. Second order filters will usually have one driver connected in reverse phase to compensate for this shift. An experienced speaker designer should be able to tell what order and type of filter is employed just by listening to the speaker as various roll outs/ins have distinct sounds which show up in measurements such as the impulse/step response and electrical phase angle. With a typical third order filter, the two drivers would be 270 degrees out of phase against each other's response and it's difficult to connect a tweeter to compensate for that amount of phase shift. A fourth order filter would be 360 degrees out of phase and many designers use two cascaded second order filters to achieve the same roll out with compensating phase shifts. It would be difficult for most amplifiers to come close to the amount of phase shift present in a typical three way speaker or even many two way designs for that matter. So, if you are listening through a speaker that isn't going to treat phase and timing with respect, you'll probably never notice what the components in front of the speaker are doing to the signal. If possible, I would suggest a listen to a single driver speaker of some pedigree to get a better sense of timing in speakers.

Quote:
He stated that equipment of lessor caliber can have timing accuracies, changing the timing relationships between the different instruments in a recording.

The sense of pace can be affected by component problems. Martin Colloms wrote what I thought the definitive treatment of this subject in November 1992 for Stereophile: see www.stereophile.com/reference/23

Quote:
I've been an Audio Professional for over 20 years and I have never heard this effect. What's any body think about this?

I have found that playing with compressors can alter the sense of pace and timing.

John Atkinson
Editor, Stereophile

It seems to me that Mr. Colloms has accurately described the problem we are all aware of...that the speaker being the weakest link. It is clear that given a specific driver's ability to "react" as fast as the other associated drivers in the system is crucial to system accuracy and why speakers will always be "the problem", and seemingly miraculous sounding one given today's technology. How could a high quality kevlar B and W woofer possibly react as fast as their superb Diamond tweeter. There is much going on here. This is no knock on B&W as I have great respect for their company and products and consider them at the forefront of speaker design and manufacturing.

Not to discount components, but I would find the "component" (talking capacitors, diodes, transistors)lag of response to be a great magnitude less, if not imeasurable. Capacitors and diodes possibly more so. Many equipment mods are replacing the diodes that make a discernable difference in sound quality. Phasing playback problems are easily discernable.

There is no doubt something is happending in the speaker relm, but I do not know if the smoothness, effortlessness that is associated with truly highend gear is the audible effect of "better component timing? Obviously as JA has pointed out drastically reducing jitter in digital playback is critical to achieving great CD playback. It is just not all of the story. Much of this has been a great help on reducing jitter in from better recording ADCs and playback buffers.

I do find this speaker issue more worthwile investigating. My interest in driver resction times is peaked.

I see a Foo-foo Tech time domain sweep reorganizer coming soon. Will also do LaserDiscs, line cords, connectors. You put your component into this box, set the delay time ya wants, on the Foo foo display panel. Turn on the Flux capacitor power supply. Let the Foo foo tech instrument do it's thang. Ya take out your component, forget what time it is, be late for work....you have thus changed time. It works!!!!!!!! $9,999.00 list price. Insudstry pricing $197.50 if ya get teh review right to their liking. Foo Foo Dust LLC. Cayman Islands. Where no man (taxman) has been before.

JA, thanks for redirecting me to MC's article. I remember reading this while I was still selling high end gear but thinking I can't discuss many of these concepts with my clients. First, I was there to sell the best music reproduction possible for the client's budget and much the minutia discussed in Collom's article was over the head of my clients who just wanted a good sounding system. Second, I was aware that telling someone a certain surround material on a driver would lead to less well timed music playback would eventually get me in trouble as I showed other speakers which employed such a surround material and which the client preferred for other reasons beyond just PRaT. Whether it matters or not, one of my personal revelations as a high end audio salesperson was that very few of my clients actually heard live music at all though most of my more well heeled clients had season subscriptions to the Dallas Symphony and a few to other national orchestras which they supposedly attended with regularity. At the same time, I had some disagrements with MC's findings which you might possibly clear up for me these many years later.

Quote:

Dynamic dilution: Realism in reproduced dynamics goes even further than this. Comparisons with live sound repeatedly show that the recorded or even just the amplified form suffers a significant loss of dynamic quality when it comes to reproducing music's inner dynamics. While an engineer might instinctively accept the notion that an audio transmission system has a finite dynamic window and that audible limitations may well be audible when waveform peaks reach the limits of that window, the idea that sounds nicely placed in the middle of the working range could still suffer in terms of dynamics is quite alien to him.

It's unfortunate that the subjective effect of all kinds of audio component errors is often a dilution of dynamic expression. More often than not, this weakness goes hand in hand with a loss in rhythm. Psycho-acous-tic-ally speaking, it may not be entirely valid to attempt to separate the two. Intuitively, one might expect that a perceptible softening of a system's dynamic quality would blur the timing cues due to its effect on the coherence and unity of the fast edges of transients and dynamic contrasts. Such an impression leads logically to a weakening in the presentation of rhythmic aspects in music. Weaken those, and the sense of drive and forward pace is also diluted.

It's ironic that you can have an extended bandwidth, or high sound levels, or great stereo imaging, or very low coloration, or powerful, low-distortion bass, or several worthy combinations of these, yet rarely can you obtain these with a coherent, focused combination of natural dynamics, pace, and rhythm. In high-end audio, we are often too busy examining the texture of the bark to see what kind of forest we are walking in.

It is undeniable that dynamics and rhythm strongly affect the emotional response to the whole musical entity. They represent the structure of the musical house, to which we can add such details as windows and decoration. However, exceptionally clear glass in a window frame is of no use if there is no structure to support it.

Whether played loudly or softly, music reproduced with good dynamic and rhythmic content competes with external factors for a listener's attention. Unfortunately, the high-end goals of purity and tonal balance often result in blandness of expression, with rather subdued dynamic contrasts. (Footnote 2) In addition, the rhythmic delivery can be perceptibly leaden, to the point where the sound is more like superior acoustic wallpaper than a committed attempt to reconstruct a live musical event.

I agree that all too often the client is listening for the bark rather than taking in the entire forest. However, the trade offs common in high end audio sometimes make for complicated decisions based on purely subjective responses to mere moments of demo material. Clients sometimes forgot they were supposed to be involved in the music and often times went looking for the most dramatic, read "palpable", soundstaging or holographic imaging. Listening for subway trains running beneath Carnegie or HVAC systems switching on in any hall was a popular diversion at one time in audio - which was not a good time to be selling Spica and LS3/5a's. While I couldn't deny the value of those items to the whole, the client sometimes seemed to be missing the doughnut in order to examine the hole. For this I largely blamed the American audio press and an uneducated public who seldom heard real music being performed live.

Quote:
There are related types of uncertainty or randomness in electrical behavior which can disturb the internal equilibrium of an electronic component. Such disturbances seem to relate well to subjective weaknesses in rhythm and dynamics.

One area increasingly familiar to amplifier designers is the effect of large transients on conventional amplifier power supplies ...

Some measure of proof that these internal effects are responsible have resulted from interactive listening tests in which some of these problems were specifically addressed by the designer. The results were well correlated with critical auditioning.

One such change examined was the size of the amplifier's power transformer. A clear correlation emerged between improved dynamics and rhythm and increased transformer VI rating. One explanation is that the larger transformer provides superior regulation, hence more stable internal power rails. Even more important, a larger transformer helps the reservoirs recover their equilibrium more quickly after a transient. Consequently, the amplifier spends more of its time in equilibrium.

It seemed to me that, for a while at least, American audio in particular spent much of its time touting power supplies, reservoir capacity and multiple regulation stages. As more and more was put into these areas, the music suffered more and more in terms of involvement. The tighter the regulation on the power supply, the less the music flowed into the room. I found myself preferring the smaller less expensively built amplifiers from a company such as Adcom over their flagship models. In my experience, the two most "musical" pieces of gear I've ever lived with are the Dyna ST70 tubed power amplifier and the Marantz 7C tubed pre amplifier, both of which had rather loosely regulated power supplies which managed to sing along with the music. The quality of the transformers on the ST70 obviously helped that amplifier along and I've suggested to friends and clients that they should listen to a ST70 and if they didn't find anything to like about that amplifier, they should stick to transistor amplifiers. It certainly seemed as though designing a power supply was more than just throwing massive transformers and multistage regulation at the project. Large capacitive reservoirs and fast recovery diodes seemed beneficial for recovery time, where the ST70 often failed, but were not the key to the timing capabilites of an amplifier such as the ST70.

Quote:

Likewise for an output stage: Increasing its capacity and/or the number of power output devices has the benefit of reducing the thermal and current effects in each one. The result is more stable output behavior. Once again, the payoff is improved rhythm and dynamics

I find myself often in agreement with ST regarding what might contribute to the making of a musical component. I understand his enjoyment of early recordings with their inherent interplay of timing and naturalness of dynamics even if those dynamic peaks are compressed when compared to the real thing. I find it is more the manner in which the dynamic curve begins and ends rather than what happens in between those two extremes which makes reproduced music what I would call "musical". This is where a 78 is far superior to a CD and vacuums to sand. One agreement I have with ST is his preference for simple, single output device amplifiers. It would appear to my ears that multiple output devices seldom succeed like single units. This would appear to be in contradiction to MC's findings. Are these just personal differences being expressed or is there more to it than that?

Quote:

In a contradiction of received wisdom, it turns out that some of the classic horn loudspeakers show much greater musical integrity, judged in terms of natural pace and dynamics, than do the majority of low-sensitivity, low-coloration systems now produced. Come back, Klipsch and Voigt, all is forgiven! Those designers' belief in outright sensitivity, and the qualities of linearity and uncompressed dynamics which this single factor confers, are still not properly valued by the high-end industry.

I imagine many audiophiles expressed surprise if not regrets that ST had lost his way when he recommended the Klipsch LaScala. I too find the LaScala to be a highly musical loudspeaker while disliking the "classic" Klipsch line beneath the LaScala. In terms of dynamic contrasts and musical expression I found the LaScala, Belle Klipsch and the Horns to be more similar to Double Advents, Quads and Magneplanars than most people would first guess. While there were enough things to dislike about the LaScala, if someone was interested in the nuance of the performance, the fully horn loaded designs from PK were at the top of their game. Now, when can we expect the resurrection of Voigt pipes and transimission line loading?

Quote:
How could a high quality kevlar B and W woofer possibly react as fast as their superb Diamond tweeter.

I guess you could say the Kevlar woofer needn't respond as "fast" as the diamond tweeter. Since the woofer is not being asked to reproduce 25,000 cycles per second it's response time should only be approriate to its own responsibilities. However, in order to integrate the two drivers the need is for motor assemblies which are sufficient for the task each driver faces and cone and suspension designs which accommodate the needs of the music. This, I think, has been adequately managed by B&W.

We are in agreement as to speaker cross-over design. I first experienced time and phase coherent speakers in a pair of Dahlquist DQ-10's (I still have them). I currently listen to a pair of Dunlavy SC-IVa's, a first order design.