I'm given to understand that signal-bearing electrons travel at or close to the speed of light irrespective of the frequency. So why should bass signals lag treble notes? Is bass-shyness a prerequisite to good PRaT? I recall Mike Hanson saying his Radio Clock demonstrated good PRaT and the PRaTiness of Kans is the stuff of legends. Unfortunately, neither have any real bass. What's the connection? I don't hear DBLs described as full of PRaT. Can I have PRaT and bass at the same time? What the hell is PRaT?

Jame

Ha Ha hahahaha! You obviously have not heard DBLs....

hock

Tow of the many elements a stereo system have to deal with are -

1 - To give the output of the system the ability to follow the exact shape of the signals that apear in the input of the system. It means that if the inputs recieve a hit on a drum, this signal has a time length of 2 milli second and a ratio of 5 mili volts between the lower level and the peak of the signal, the signal in the output
have to continue exactly 2 m"s and to keep the exact ratio of volume the original signal has in the input (although in the output the volume is many times higher than in the input). It is very complicated because of the very complicated shape
of the audio signals.
To do this job, I think you have to have electrical elements who are acting very fast to changes in volume by time.

2 - Every electrical element responses differently to different frequencies. The stereo system deals with frequencies from 20 Hz to 20 KHz - it is a very large and tough distance
to deal with because of the nature of the electronic elements. If the system doesn't deal with it as it should, it means that a low frequency instument - say a contra bass - will apear in the output not at the same time with
cymbals although both of them feeded the input exactly at the same time.

The ability to deal well with different frequensies is as important as the ability to follow the shapes of the input signals and that is why I'm not sure that that the quick transistors is the only "magic" of Naim, I even don't think that if it was the only, other manufacturers couldn't follow this secrete, I think Naim equipment is full with secretes and maybe some of them are more amazing and beatiful than fast transistors

Maybe Naim will tell us some of them ? ....

Telling all this I think the qulity of the bass depands on many features of the system, not just timing.

Arie

Not answering all your questions, but just a related topic :

Julian once stated the opinion, wrt amplifier design, that it's not what you do right, rather it's avoiding doing wrong. And that's why many sophisticated systems f*** up all kinds of things including prat, which some simpler systems still maintainm simply because a sophisticated system has many places it can screw things up.

And where's Mike ?

Omer.

BTW I don't see why prat should be more affected by amps than source or loudspeakers.

[This message was edited by Omer Shibolet on FRIDAY 24 November 2000 at 09:16.]

Rico - musichead

Glad to see you here...

You have to be highly SOPHISTICATED to make things SIMPLE.

Arie

Alan

quote:

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Since a square wave is made up of the fundamental frequency and an infinite number of higher ones, they will travel at different speeds and end up with time distortion. I suspect that naim kit is very good at avoiding this type of distortion.

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Almost any amplifier will give very good square wave responses at 1k,and most will at even 10k. The few ones that do defeat the pythagorean paradox of circling the square are the round-earth tube amps, especially the single ended variety. On a good day the 'square' waves look more like shark fins- with fin rot too!

But before too much derision is cast upon these breed of amplifiers, it must be pointed out that cartridges too (yes, even the Archiv B) have horrendous square wave performances.

The theoretical strengths of Naims poweramps are difficult to distill into one or two key features. Full regulation certainly is one of the features of the 250/135/500. But even ones lacking full regulation can really make music, so the design principles common to them all must be just as important. All of the amps have a purposely defined performance envelope that is partly the amplifier itself, partly the electrical parameters of the speaker cable and partly the 'conditioning' of the incoming signal by the obligatory naim preamps. Other key elements that make the system work as a whole include scrupulous attention the electrical grounding.

Unless we are going into the amplifier design and retailing business, it is not really that important for us to know WHY they work so well, just to be able to appreciate how well they work.
I use mine every night.... do you?

Ron
Dum spiro audio
Dum audio vivo

http://homepages.go.com/~rontoolsie/index1.html

Yes--and more and more with the system I have now than I did with active SBLs or ProAcs.

Something else Julian said was that balance was one of the keys to the sound of Naim (in an interview with Art Dudl ey in "Sounds Like" magazine). One of the strengths of the 250 (the subject of the review) was that no one parameter was stressed over others. It is this holistic view, more than anything IMO, that accounts for the Naim sound.

Maybe the most importa n t element is where Julian started from: he wanted amplifiers that would play music, not make noise, and he followed what HE thought, not the cookie cutter approach to amp design. (Although I have heard and read others criticizing Naim amps for being cookie-cutter types, most have never actually heard a Naim system.) Interesting that in most musical respects the earliest designs from Levinson, Krell etc tend to be the most "musical" even if they have "improved" over the years.

Cheers,

Bob @ Qwest
[This message was edited by Bob Edwards on FRIDAY 24 November 2000 at 16:20.]˙

[This message was edited by Bob Edwards on FRIDAY 24 November 2000 at 16:21.]

quote:

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Errr, James has actually been exposed to DBLs; sadly he has not yet been wheeled before Jawed's or Joel's... all in good time, eh?

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Too right, but the first thing that stuck me about DBLs on all 3 occasions I've heard them was how loud they were. Sure, they have dynamics aplenty and do present a very fulsome sound. It's just that I've never heard people refering to DBLs as the definitive PRaT speaker, which is not to infer they have no PRaT.

When PRaT is spot on, it's plain as day. However, when it's off, how easily can one point the fault to a specific link(s) in the hi-fi chain? I'm fairly convinced that PRaT is not an absolute measure and that various hi-fi components have additive and subtractive effects on PRaT. Hence, to conclude that the CDX times like its life depended on it would require equally time-aligned kit downstream. Would DBLs time nearly as well at the end of Musical Fidelity amps? Tony Lonorgan might have a view, as others would I'm sure. How do Dynaudios time at the end of the Naim chain?

Perhaps it's time for me to consider an all-Naim system to put the PRaT ghost to rest. Has anyone seen SBLs in rosewood?

James

Obviously, all of the frequency range produced by the speaker must play in time with everything else.

As you try to reproduce deeper bass this seems to find more frequencies which the room has problems with - usually a resonance which slows things down (or a null which cuts it out). Careful speaker positioning can mitigate this, as can more soft furnishings.

A few rooms just seem to sound great without any major effort.

BTW, it's not just big speakers. A bigger amp or source can give you more useable extension, and just the same problems.

But whatever the potential problems, that extra octave or two really is worth fighting for.

cheers, Martin

"Pace, Rhythm, and Dynamics" by Martin Colloms