What is Audio "Dirt"
We know why and how the phenomenon OF AUDIO DIRT occurs AND how, as a result, it is possible to go a long way in CLEANING IT UP to improve the sound of virtually ANY audio component.
What's the secret? If you'd like to know MORE continue reading below and feel free to pass the word. Science DOES have the answer, but few until now have understood the science. For those that believe in magic and "Pixie Dust," we make no apologies for the following. Sorry, ignorance is NOT bliss. In fact, frequently it can end up being quite expensive and wasteful.
Hidden Artifacts Are Messing Up Your Music
Any experienced audiophile or audio professional knows that audio product specifications seldom make for a good indicator when it comes to predicting the actual "sound" of a given audio component or making comparisons between different makes and models. The primary reason for this is because the test instruments employed by the audio industry mainly focus on what is termed "large signal conditions;" meaning that the test signals used are large enough in magnitude such that they can be easily measured themselves apart from any distortion artifacts being generated by the audio component under test.
As a consequence of the above, for the most part the magnitude of the distortion artifacts being generated by the component will be relatively large signals as well. Therefore, much of any residual audio "dirt" that we are concerned with here, being either uncorrelated or only loosely correlated to the testing process and its associated distortion artifacts, will simply be masked by them and go undetected.
In other words...
Common Noise ("hum" and/or "hiss")
We have all heard the common effects of electrically generated high frequency and 60Hz AC power noise that often emanates from audio systems to one degree or another. "Hiss" and "hum" are common annoyances, but fortunately the majority thereof can be traced to external sources such as poorly shielded cables, bad ground or signal contacts and/or ground loops, etc. In those cases the owner or user usually has the opportunity to address and remedy the problem by following established methods known to work in such cases. After all efforts have been expended in those efforts though and proper corrections have been made, there often remains a residual level of noise that cannot be eliminated by any external means. That form of noise is actually being generated within the various components comprising the system, so the only way possible to reduce or eliminate it is to address and correct the underlying conditions and inferior sub-systems within each of the component devices.
To a large degree, doing the above is one of the main cornerstones of D.R.R.T. ...
Circuit Contamination from EM Radiation
Whenever voltages fluctuate across a given part or wire, Electromagnetic Radiation comprised mainly of electrostatic (E-Field) energy can emanate or “transmit” through the air outward from that location. Similarly, when currents flow through conductors or component parts magnetic (M-Field) energy can do the same. The transmitted energy can then be picked up once again by another receiving location (i.e., by a wire or transformer, etc.) inside that same component and be injected back into the circuitry that generated it.
In essence, the device in question has now become its own worst enemy because such "self-contamination" can create the equivalent of unintended "feedback loops" within the component, which is never a good thing. That's because the process can be extremely complex and therefore create an exceedingly complex set of conditions that were never accounted for (nor likely could they be) in the component's Transfer Function during the design & development phases of the product. The end results are virtually unpredictable other than the fact that product performance will almost universally be affected negatively to some degree.
High Frequency Switching Noise
This type of noise is mot commonly caused by Class-D amplifier circuits and/or the clock oscillators used for timing in digital circuits such as are in most DACs, and are known to be caused by what is commonly referred to in electrical engineering as "Ripple Currents.” If not completely filtered out, this noise may find its way into various audio and/or DAC circuits by way if their DC power supply. Due to its cyclic nature from being generated by an oscillator circuit, the noise can cause various types of distortion due to its interaction (inter-modulation) with audio and other nearby clock signals.