The "great" sound of reel to reel explained

It was not an analogue versus digital, which sound better? article; but rather and article concerning why added distortion, by way of phase manipulation and harmonic enhancement/restructuring, has pleasing effect that many qualify as sounding "better".

Carlos, I realized that right away- the problem is this article is coming from someone who does not know what is possible in the world of high end audio, assuming that things can never sound real. His initial assertion that digital was such a great thing for audio... well, the fact of the matter is that a lot of the analog manipulations that he mentions in his article have appeared **as a result** of how bad digital is.

There is a definate portion of the audio community that simply does not have any idea of how good audio playback has gotten, and on top of that seems to think that anyone who does try to push the art is in fact not doing anything, because they are a complete nut. This community uses simple assumptions, like 'tubes=distortion' and other arguments we have seen here already. Tubes don't have to have any more distortion than transistor amps- I've built tube amps with THD at full power under 0.01% for example. If you use techniques that the transistor guys use to get low distortion, you can do the same or better with tubes, if you know what you are doing.

Now its a different matter as to whether or not its a **good idea** to build any amplifier with distortion that low. Here's the crux of it: any amp with distortion figures like that is likely violating a fundamental rule of human perception, which is how we perceive the volume of a sound. So in high end you see a lot of designers that build their gear to **not** make the distortions that the ear cares about, and likely are not worried about the distortions that the ear **doesn't** care about. Such equipment may not look good on paper, because the paper specs have little to do with human perceptual rules.

Tape happens to be a medium that makes very low distortions, at very low level, quite the opposite of digital, which is guilty of increased distortions at low level. Unfortunately, tape, by driving it too hard, has become an effect in the studio that is not representative of what it is capable of. Its when you drive it hard that it can pick up distortions that become audible.

Here is something that that community I mentioned does not like to hear: distortion plays a greater role in coloration than frequency response does due to how we perceive sound.

Inconveniently, the most obvious and pesky colorations to the human ear are also ones that are hard to detect with modern distortion analyzers: the 5th, 7th and 9th harmonics for starters but also the inharmonic distortions generated by digital equipment. These harmonics are percieved as harshness, the need to turn the volume down (IOW if your stereo ever sounds loud to you this is the reason why- most people never listen music anywhere near the volumes that it actually occurs in real life since their gear will get too unpleasent to be in the same room with, even if it could make the volumes) and the like.

It is true that lower ordered harmonics are perceived as warmth, and it is also true that this type of distortion will mask detail. However, it it not a failing of tape or tubes **unless you want it to**, IOW if you set out to intentionally make it so.

Bottom line is that IMO/IME digital and transistors are far more guilty of coloration than tubes or tape, and the colorations are the type that are outright unpleasant (ask any audiophile and you will find that the majority of listeners really hate excess brightness). This is not to say that they can't work, its just harder, and the transistor amps and digital gear that really do make music are few and far between.

My point, Mitch, is that Wikipedia is hardly a "verified" resource but yet so many people want to quote it or point to it.

As for the topic, I don't really care why it sounds better.

Ralph,
The truth of the matter is that the only way to make digital sound like analogue is to add distortion. This is not confined to the studio/professional-audio world; have you seen the measurements in the review of the the Playback Design MSP-5 SACD player in Stereophile? There have been many AES papers written on how adding distortion helps increase clarity and enhances low level detail. It is also common fact that most Audiophile find equipment "clinical" or "analytical" sounding often are the same with low THD and great linearity measurements. You can arrive at the logical conclusion right????

It is also common fact that most Audiophile find equipment "clinical" or "analytical" sounding often are the same with low THD and great linearity measurements. You can arrive at the logical conclusion right????

Carlos, not to put to fine a point on it but it appears that you have not understood what I have written or did not read it. You are correct in your statement above, but its important to understand why audiophiles use these terms to describe equipment that measures like that.

Its because it uses large amounts of loop feedback. This technique, while resulting in 'high linearity' (in a broad sense) and low THD comes at a serious price: loop feedback enhances the 5th, 7th and 9th harmonics used by the ear as loudness cues (as I have at this point mentioned several times before). That this is the case is easily proven by anyone with simple test equipment.

General Electric proved about 1965 or so that humans will not tolerate even trace amounts of this distortion, as we use these harmonics as loudness cues; arguably we are more sensitive to their distortion than we are human vocal ranges.

IOW, loop feedback violates a fundamental rule of human hearing when used to get low THD and 'high linearity'.

This is why your statement is true, although the reality that underpins it seems to be counter-intuitive. It is not a convenient fact, because linearity without loop feedback is difficult to achieve. However, if you think about it, linearity on paper is not real if the ear thinks its wrong! I guarantee that if we did not have ears, we would not play with audio devices; the ears are the most important things that any audiophile has.

With regards to the previous statement:

The truth of the matter is that the only way to make digital sound like analogue is to add distortion.

You can *mimic* analog in this way but it will not **sound** like analog! This is a common myth; you cannot increase detail and improve transparency by adding distortion, because distortion will mask low level signals (masking is a rule of human hearing BTW). Digital **already** lacks low level detail. So if you were to mask details even more, the difference between the analog and thus-doctored digital is immediately apparent.

Ralph,
To quote an Audiophile approved source, John Atkinson:

Perhaps his description of its sound being "analog-like" is a clue—for reasons that are not fully understood, a signal with very-low-level random noise added is sometimes preferred, on that it is more intelligible, to the same signal without such noise; See, for example, "Stochastic Resonance in Acoustic Emission," M. Friesel, Journal of Testing and Evaluation, 1999, and "The Benefits of Background Noise," Moss, Wiesenfeld, Scientific American, August 1995.

From the AES documents library:

Aural Exciter and Loudness Maximizer: What's Psychoacoustic about -Psychoacoustic Processors?-

In this study two so-called -psychoacoustic processors- are examined exemplarily by applying concepts, models, and methods of scientific psychoacoustics. Physical measurements of processed sounds and results of hearing experiments on speech intelligibility and sound quality (Aural Exciter) and loudness (Loudness Maximizer) are presented and discussed with regard to classic psychoacoustic models and potential new applications. Therefore relevant psychoacoustic facts, in particular the perception of nonlinear distortion, are reviewed.:

Author: Chalupper, Josef
Affiliation: Institute of Human-Machine Communication, Technical University of Munich, Munich, Germany
AES Convention:109 (September 2000) Paper Number:5208