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Wednesday, August 13, 2008

DPOLS or Dead Points of Live Sound - Thanking Romy the Cat and his GoodSoundClub

The “Dead Points of Live Sound”

This, from my prospective a superbly truthful article, was written by a Russian guy A. Polakov. I do not know who he is but the accuracy of Mr. Polakov’s experience regarding the subject and very similar Mr. Polakov’s and my observations of the issues made me to make his article available in English. Approximately 5 years ago I have written something similar and posted at AA but now that post is long gone (courtesy to the idiot who moderate the High Efficiency Speakers Forum). I have no longer that deleted form the AA original post but this subject is so important and so grossly overlooked and misunderstood by audio people that I found that it would worth to touch it again.

The text below is not a literal translation but a “very liberal translation” where I will slightly accent and stress some points, subdue and retouch some others. In some cases I did some rectifications and corrections where I filed it would be necessary. I some cases I even the Mr. Polakov’s position. However, the core idea of the article is very much the same as Mr. Polakov’s had. In other words it would be a very free and very liberal translation….

About the “dead points of live sound”.
Romy's translation-interpretation on the motives of A. Polakov.

It is know that there are many ingredients responsible for “quality” of audio inhalation. Unquestionably one of the most important is the listening room’s reaction to the installed loudspeakers. There are countless solutions how to work with listening rooms and the cost of this “working” in many cases might exceed the cost of the playback components.

Yes, the performance of loudspeakers might be very dramatically changed by the rooms and most of those improvements would be centered to find a correct positioning for the acoustic system in a listening room. Everyone knows that the positioning loudspeakers have an impact on Sound. However, with the REAL depth and imperativeness of this impact very few are familiar. It is pointless to perform any actions targeted to improve performance of playback, including the change of the component of the playback chain or the room acoustic treatment, unit the correct positioning of the loudspeakers in a given room would be found. There are no formulas, programs of any methodology that would simplify this process and the only “tool” that might be use is subjective perception of the audible result. The rules, circulations, abstraction, approximations and the entire practice of position of loudspeakers according to minimization of stay-waves are a juts very rudimental and primitive approach. After the optimum stay-waves location was found it might be considered only a very beginning.

An optimum location of loudspeakers might be called an “optimum zone” beyond which the subjective characteristics of the loudspeaker’s performance degrade very rapidly and very aggressively. For a typical “box” loudspeaker and within an average 400-700 sq feet room the dimension of the “optimum zone” usually within .5-1 inch and the deviation form the towing-in usually within 2-3 degree. Some audio people (approximately 15% of them) were able to determine the correct “optimum zone”. Whoever did not do it was not able to utilize a full potential capacity of thier playback systems. However, practically no one, even among those lucky 15%, knows anything about the “dead points of live sound”. When an acoustic system is placed into those “dead points” than all improvements that comes with placing the loudspeakers into the “optimum zone” really jump over the roof. The “performance yield”, when loudspeakers hit the “dead points”, is much higher then when the loudspeakers are juts placed inside the “optimum zone”. To describe what the “dead points of live sound” I would say that inside of the “optimum zone” there is one smaller zone. The dimensions of this smaller zone are within the scale of 1/16” –1/32” and therefore this zone might be called - a single point in space, or the “dead point of live sound” (or the DPoLS further on)

This effect was found purely accidental within context of one installation. Then the DPoLS was found within others installations, which suggests that this effect is a typical. In all occasions the gain of sound’s quality took place very aggressively and the gain of quality disappeared when the loudspeakers were removed out from the DPoLS. This suggests that the DPoLS might be discovered if one is intentionally searching for it. The probability that the DPoLS will be hit accidentally is practically equal to nothing. There are no publications or methodologies on the subject. Therefore, below are listed some subjective characteristics that an acoustic system do when the loudspeakers are placed into the DPoLS:

1) When the loudspeakers are placed into the DPoLS then all characteristics of sound improving very strongly: imaging, space localization, transient, dynamic range, space presentation, tonal contrast and many other. Even the tonal imperfections of reproduction become way less notable and less prominent. What is characteristic that the improving takes abruptly, very expeditiously and swiftly.

2) The strongest improvement takes place in the subjective domain, reflecting the emotion and spiritual content of recording. The DPoLS highlights the energy of performance; boosts the ethical load of the musical content, highlight the intonations and the timbre connections of the musical phrases. Starting with a certain level of capacity of the rest reproduction chain it is possible to talk about not “reproduction” but about the reinstating and resurrection of the “original energy of live”.

3) A conversion from a regula-audio sound to the “alive sound” takes place very rapidly when the speakers enter the DPoLS. This conversion is greatly catalyzed by an ability of a playback to handle LF.

4) DPoLS exist for mono and stereo installations. In case of stereo the DPoLS is a correlation of both DPoLS for each channel. The DPoLS spots for the individual left and right channel might not have the same location when the system operates in stereo mode.

5) The relation between the towing-in and excursion the loudspeaker into the room, when the loudspeaker is located in DPoLS, is very high. In DPoLS this relation is way higher when in a satiation when the loudspeakers are juts positioned on the “optimum zone” of a given listening room.

6) The correction of “quietly of Sound” by moving loudspeaker within DPoLS is imposable. Any deviation from the DPoLS is worsening sound. Since the loudspeaker is in the DPoLS then the room/system operate in its absolute maximum capacity.

7) When the loudspeakers are in the DPoLS then the “sweat spot” increase very dramatically and in many cases it might spread across the entire room. If the output from one loudspeaker would be even blocked then it be less significantly impact sound compare to the impact if the loudspeaker were not in the DPoLS.

8) The sensitively of loudspeakers from the minute arrangements made in playback system become very high. The loudspeakers begin to act as a very strong magnifying glass that highlights everything. However, this emphasize, if it emphasizes the negative properties do not necessary have a negative impact to the listening experience. I would say that that if you system slightly off the mark after the “highlight” then the subjective affect of this emphasize would be very different then if the loudspeakers would be not in the DPoLS.

9) When the loudspeakers are installed into the DPoLS (disregarding the cost and typology of the loudspeakers) then listener is far sooner get “hypnotized” by sound. The playback become to sound “significant”, “important”, demonstrating the “playback pomposity” and some pretentious. The process of listening perceived by a listener at the very different level and it is practically imposable to do the “casual listening”. The carelessness and the inattentiveness of listening become practically imposable. Sound become not juts a “Sound in the room” but an absolute dominating and demanding force in the room

10) The sensitively of the loudspeakers installed into the DPoLS to the effect of Absolute Phase become incredibly strong. Flipping the Absolute Phase in the DPoLS does not just change the structure of bass removes the fog from the lower midrange and settle down the HF but kind of turn the entire room upside down. To discover the DPoLS is imposable if the system is not set in the correct acoustical and electrical Absolute Phase.

Upon the said it is possible to make following conclusion: a major obstacle in building a high performing playback installation is unawareness of audio people about the DPoLS. The audio and listening benefits that might be received from placing the acoustic systems in the DPoLS are huge, order of magnitude exceeding any changes of loudspeakers of components. A lack of any structured methodologies and guideness that would enable the audio people to discover the DPoLS is a very severe impediment in order the knowledge about the “dead points of live sound” became a common practice among the audiophiles.

Thanks to Romy for this translation (and for his FANTASTIC "GoodSoundClub" Forum and site, always full of hints and inspiration...not a brand new theory, BUT so important to point it out, from time to time.

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