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.

rdrysdale wrote:

So how do you suppose the proper DPoLS can be located? With a system like Steve Schell and I are working with, everything weighs hundreds of pounds and to properly evaluate changes would take days, maybe even weeks for one room. I suspect that the materials that a room is constructed of would also affect all aspects of the proper set-up position, especially the design of the floors, whether raised foundation, or solid concrete slab.

My acoustic system is not in the “points” currently. I am waiting when I finish my Super Melquiades amp when each driver will have own dedicated and optimized amp and then I will try to place my “Macondo” into the “points”: it will be too complicated and I do not want to waste time doing it now. Last time my acoustic system was in the “points” it was during 5-6 month in a middle of 2002. It was phenomenal, absolutely phenomenal! At the time I was able to remove the speakers out of the “points” and place them back relatively easy.  At that time my speakers were sitting on 3 spikes sand I made the very precise marking on my floor. Sticking the spikes back to the floor's holes I was able to be "almost there" and then it took a day or two to find the “point”. Then I change a preamp and never was able to find the DPoLS.

My current acoustic system – “Macondo” is about 500 pounds each channel. The woofer towers are 200 pounds and it is not problem to move them. The rest are 3 channels of horns. They all are balanced on the rectangular sand-filed base with a very small footprint, approximately 10x10. When we made the bases I asked John Hasquin to make them ¼” shorter then it necessary to balance my upperbass horn. The reason is that I glued under the bottom of the base 4 large furniture sliders (my Macondo sits on a carpet). Those sliders are very nice, I do not remember the brand name but they are ~$18 @ Home Depot. With all of it the Horn are very steady but at the same time quite manageable if I want them to be.

I think that when I hit the time when I go for the nailing down the DPoLS than I will be able to move the speakers without recruiting a moving company… The problems is the even with having a dream - the speaker position remote control (kind of motorized base on wheels) - it still might take weeks or even months to find those damn DPoLS… :-(

Yes, the live is a bitch and then we die… but this is the name of the game… :-)

Rgs,
Romy the Cat

rdrysdale wrote:

Do you think it would be possible to find the proper location by using a smaller pair of speakers, and then substitute in the big horns? At least to get to a close position?

rdrysdale wrote:

Our big horns are rarely moved more than a couple of inches in any direction, but we have had times when the playback is incredible, where an orchestra is laid out in front, fully three dimensional, and very beautiful sounding, but many times we have simple flat imaging with no depth.

rdrysdale wrote:

We are always careful to place the speakers equal distance from the listening position, within about 1/8 inch or less, but I never measure the actual distance of that position,  only that they are equal, and equal distances from the walls.

Somewhere within this thread (or perhaps somewhere else) I have mentioned that my own playback systems last times was dead-installed into the DpoLS approximately 5 years ago. I kind of did not make a whole a lot of attempts with DpoLS since I was doing something with speakers and with power amplifiers. Now, since the Super Melquiades is finished, optimized with the Macondos and the only thing that I do with my playback is turn it on and off. I thought that it would be a good time to see how the system might react to the DpoLS proximity. So, since everything is locked I was slowly starting to move the speakers (within 4-5 inches). After a week I was able to found more or less interesting position that slightly turn the system on. I’m quite far from the exact DpoLS positions. I would say that I am still ~2 inches away (that is HUGE for the DpoLS) but I do feel that I move to a correct direction, regarding the DpoLS nearness.

Will see what I would fine myself in a few weeks…
Romy the Cat

Continuing in my quest to the finding the new DPoLS with my Super Milq I did some “critical test listing” today. I’m certainly getting closer. I spent a few hours to play with the playback and I recognize that the first signs of the approximation of the DPoLS have begun to manifest themselves.

For instance the narrowing distance between the channels increase the width of that damn audiophile’s soundstage, whatever it worth. Generally the setting the speakers wider from each other make soundstage wider. Yes, with the certain topologies and with very certain infrequent applications moving the speakers closer might wider the soundstage. However, no mater how you make it wide (moving speakers closer to each other or further) it always has a reaction by diving the center image deeper INTO the soundstage, creating a virtual soundstage horseshoe.  The fan part that when the loudspeakers are closeting to the DPoLS then the narrowing speakers or toeing then out create a wider soundstage AND at the same time the center image movies FORWARD. The effect is larger the closer the loudspeakers to the DPoLS. (When loudspeakers ARE in the DPoLS then the entire concept of soundstage get wiped out)

Another, factor that signalizes that my Macondos are closing to the DPoLS is the ability of the speakers sound in and out of default listening space like “live” Sound. You know, when you approach for instance a brass band playing form its side then you do not hear it as you hear a loudspeaker form it’s side. However when the loudspeakers in close proximity to the DPoLS then the feeling off and on the “side sound” is VERY different that typical might be exacted from audio, not to mention the horns (When loudspeakers ARE in the DPoLS then the entire concept of “side” sound get evaporated)

I wish I would not screw the things up farther up and will be able to catch the exact DPoLS. My estimate that I’m 25%-30% in  there. It gives abstractedly speaking 10% of “better sound”. When I will be 60%-70% there it will yield an extras 20% of “better sound” and when the Macondo will be exactly at the DPoLS then it will produce 300% of “better sound”.  Still even now it is quite fascinating to listen it.

For a time being I really hate this man: John Hasquin. Each time when I move a speaker for ½ inch I grab this damn upper-bass horn along with it’s zillions kilograms and I curse the day when I was introduced to John.

Rgs,
The caT

Romy the Cat wrote:

For instance the narrowing distance between the channels increase the width of that damn audiophile’s soundstage, whatever it worth. Generally the setting the speakers wider from each other make soundstage wider. Yes, with the certain topologies and with very certain infrequent applications moving the speakers closer might wider the soundstage. However, no mater how you make it wide (moving speakers closer to each other or further) it always has a reaction by diving the center image deeper INTO the soundstage, creating a virtual soundstage horseshoe.  The fan part that when the loudspeakers are closeting to the DPoLS then the narrowing speakers or toeing then out create a wider soundstage AND at the same time the center image movies FORWARD. The effect is larger the closer the loudspeakers to the DPoLS. (When loudspeakers ARE in the DPoLS then the entire concept of soundstage get wiped out)

Romy the Cat wrote:

Twogoodears, What you are experimentation now has yet nothing to do with DPoLS. You deal with the relatively rudimental ceremony of speaker positioning. It is not even close to the subject of DPoLS but it is also greatly neglected by majority of people out there. People with small monitors still deal with it in some ways, the people with large DIY horn intentions are deaf to speaker positioning (at least among what I was experienced). Toeing of the horn system is very tricky subject, particularly in a nearfiled. The “hole” in the middle and the back-image curve are also tricky subjects… I am glad that reading my DPoLS article made you to think and to look into it…. but it has, as I said above, nothing to do with DPoLS. The Cat

DHT4ME wrote:

In reading this thread I am compelled to ask the simple question about the rest of the room. In my experience moving furniture and room treatments also make a huge impact and must certainly inffluence the perfect lcation for any room as specifically treated. As a first impression I see little mentioned about the details of DpoLS implementation just lots of superlatives.  I understand the goal and the methods but feel that somewhere the whole subject needs to be refined from an abstract theory to a set of observations from statistical experimentation.

Bob, you are right, some elements of the room as well as change of some elements of playback might throw an installation out of the DPoLS. Also, you noticed correctly that I do not go into high specifics and detail methodology regarding the DPoLS discovery. There are few reasons for it and one of the major reasons that all those aspects are very specific to a given installation. I prefer people understand a concept and were informed about what they do not know but I would abstain from direct instruction how to get there. Given the “freakishness”  of the DPoLS’s outcome and the fact that 99.9999999% of people who even read the article above have never experience the DPoLS effect and never knew (never will know) what the DPoLS is all about I do prefers that the people rediscover the DPoLS effect themselves.

It is not that I state that there are no short-key methodologies available to find the DPoLS. There are some algorithms and (believe me or not) there are even objective tools that indicate a proximity of an installation to DPoLS. However, I found that it would be very difficult, if even necessary, to explain HOW the “thin fields” of audio work to a general public, the public that is commonly immune to evolved aspects of audio reproduction. (Not to mention that I do not pretend having a FIRM knowledge in the “thin fields” of audio, I rather have an intuition, results and some patterns but not the knowledge).

So, you criticism of me spreading nothing more than “abstract theory” about the DPoLS is very correct but it is very intentional.

tuga wrote:

Hello Romy, Could you elaborate a bit on your experience with the toeing in of horns subject. My square mouth horns are probably even trickier than round horns to fine tune as the higher frequencies seems to radiate in a flowery (petal) shape.

Tuga,

Sure the horn toeing is very interesting subject but we need clearly undusted that it has no relation to the DPoLS topic. There are two major aspects that make horn toeing different from any other speaker horn toeing: the extremism of nearfield and much greater varying of horn frequency response with toeing. The rules of horn toeing would depend from how aggressive the horn used in nearfield, the frequency parameter derives from the depth of nearfield. If you use horn at 25 feet then the rule is very different then if you use then at 8 feet. Also, the type of the horns and allocation the signal by channels superbly affect any judgment and result of the horns toeing.

You see a horn is not self-exclusive definition and there are many horn-loaded configurations. There are also properly done horn systems and there are incorrectly done horn systems (most of them). The rules of toeing that would apply for properly done horn systems are the rules. The rules of toeing that might work with incorrectly done horn systems are no rule but juts examples to mask out other problems of this specific installation.

So, to talk about the horn toeing it is necessary to know at least the following factors: number of channels and how they crossed, properness of the channels integration, minimum integration distance (MID), relation between the MID and the distance between the MF island and the room’s boundaries, correctness of the horns death to the given amount of channels, proximity to DPoLS, reverberation time in the room at let say 60Hz, speakers opening angle, and many many other factors. As you see – without sitting in the room with a given speaker system it is very difficult to say anything certainly and to be right.  As you might see anywhere else in my site I do my best to sabotage any conversation about exact the speaker positioning. I feel that it is possible to talk “over the phone” about speaker positioning if to view the subject from 50.000 feet but as soon we hit the subject at the height of the tweeter’s proximity to floor then all generalizations are out and the specific reaction to the given listening experience shall take over.

From an email that I got today:

“Just in one time I listened a sound that it's character was so close to your description about DPoLS ponit. That time me and my friend never think the placement was cause of good sound. My friend changed speaker position and we never find that night magical sound. Please if you have any experience for finding DPoLS guide us for finding this point at less time.”

Well, what can I reply?  Welcome to the club. Not the GoodSoundClub but to the club of the people who went, in may instance for many times, over the very same things as you went over with your friend. I experienced DPoLS a few time, twice with my own playback and in all occurrences I lost eventually and was forced to move speakers or do some other changes. Unfortunately I have no essay guide for finding the DPoLS, I am familiar with a few but I do not endorse them as I consider them not correct. Regrettably the only known to me “true way” is to keep moving those damn loudspeakers and keep teaching yourself to understand what you hear.

As a very general guideless the system installed in the DPoLS very much reminds a person that is in love. What you in love that all criticality toward to the subject of your love got evaporated and each manifestation of the subject you recognize as a magic blessing. Furthermore you feel as unique consumer of that magic, the consumer that have exclusive and special appreciation of those inspirations that comes from the subject of your love. Each single time I experienced the DPoLS I field exactly like this in relation to the sound I played.  The playback in DPoLS is a superbly powerful subordinating force in front of witch you absolutely voluntary give up and joyfully submerge yourself into the depth of the listening masochism

Somebody “aehaas” from Florida got new large Wilson and wrote about his experience. The writing was posted at avsforum.com – the site invested by idiots of all calibers, and the comments and responses to the aehaas’s writing are a good evidence of it.

http://www.avsforum.com/avs-vb/showthread.php?t=1154494

I do not like a few things in that right up and I do not like very much the way how aehaas describes the sound of this installation but (to me it is a typical ML sound) but there was a moment in there that is worth to pay atantion.

Aehaas wrote: “One thing I learned was that a quarter inch of movement can make a big difference in the sound quality.”

We all know that Wilson for a long time advertise this speakers arrangement techniques as something that would allow to get much better sound from their speakers. I would not doubt it as the topology of the larger Wilsons is very much prone them to be DPoLS dependant. Now, the question that I would ask: Does the Wilsons speakers’ arrangement rise to the DPoLS level or it is just speakers arrangement?  It is hard to answer.  I am sure that dealing with somebody at higher echelon of Wilsons it would be possible to collaborate this subject. At the low echelon of the Wilsons food chain (regular dealers, reps and the rest sales junk) of course there is no people worth to talk about it.

I remember a few years ago I have seen the written direction how Wilsons was teaching his dealers to setup speakers. Does anybody have it now by any chance? I would like to review it in context of DPoLS/

Romy the Cat wrote:

I remember a few years ago I have seen the written direction how Wilsons was teaching his dealers to setup speakers. Does anybody have it now by any chance? I would like to review it in context of DPoLS/

Since my new room is set and the playback is installed and configures I name an interesting observation:

http://www.goodsoundclub.com/Forums/ShowPost.aspx?postID=1500

Continue to think in this direction I come to very promising hypothesis that I would like to try if my Macondo would not be so huge and heavy. To make practical experiment on it I would need to device a mechanism to move Macondo’s right with very high precision but considering the size and the mass of the thing I do not have this option for now. If someone would devise foe me such a mechanism then I would appreciate it.

Anyhow, back to the inspiration/ hypothesis that I have. The inspiration suggests that time alignment is the key for DPoLS setting. However, here the time alignment needs to be understood a bit differently. Usually time alignment implies the arrival of the sound from all channels of the same loudspeaker at the very same fraction of phase. The DPoLS Time Alignment ™ is a different animal. It implies a Triple Time Alignment:

1)      Alignment  of the Channels of the same loudspeaker
2)      Alignment  of BOTH loudspeaker in the room
3)      First major reflections of the room for both loudspeakers.

This is in a way a revolutionist thinking about Time Alignment as it does not imply the Time Alignment itself but a combination of Time Alignment with benefits of Time Alignment. Let me to explain as it might be a bit confusing die to my careless use of definitions. I will explain it on examples how I feel the DPoLS might be found (if my theory is right) fully predictable, methodologically and without even listening the loudspeaker.

So, you get a pair of loudspeakers and a room with comfortable foe you reflection pattern. You set up left loudspeaker (left for you) where I need to be. I always suggest starting from left loudspeaker as it cares the fist violins, sopranos of choruses and generally in western culture is associated with HF lead. You take RTA or TEF pulse analyzer and perfects align each channel of the loudspeaker to your listening position. Then you take a right loudspeaker and do the same. They the fun begins. You need to align the right and left loudspeakers to each other in respect to this position in the room. We are not taking here about arrival time and it will be skewed and hardly measurable as we will not be able to subtract the modulations from reflections. So you take pulse analyzer away and using just TRA we are trying to setup R and L loudspeakers to have max amplitude of each other impact.  Here is where you deal with true DPoLS.

Here is where you deal with true DPoLS: a single mm of moving or angle of right loudspeaker does impact sound but it also impacts the RTA summation if you use a high resolution (let say .25dB and higher). I need to warn you that the operation at 0.1dB level non-anechoicly from let say 10 feet is very tricky and generally might be considered idiotic. But the whole point is that you want all live reflections of your room to be inclusive.  You might use cancelation after a few ms to deal only with fist reflections. Anyhow, you objective is to setup your R loudspeaker with as low conflict to your L loudspeaker and to your room. The microscopic movement and angling of your R loudspeaker acts as a lubrication that put your R loudspeaker in micro-phase conflict-less operation. This is in my theory is a condition for a proper DPoLS operation.

Now, SOME aspects of the theory above I have tested and was able to get very substantial gain of performance. I did not apply the success to the whole Macondo, I will but to do it I need a full house of strong hoodlums with tools what would very precisely moive my speakers according to my instructions. I very much willing to do it sometimes but the Macondo frame is not friendly for this task.

A note I need to make. The above method is a method with using of tools of objective control. The very identical result might be accomplished by specific targeted listening if a person knows what and how to listen.  However, I do not think that those skills might be delegated in article and I will refer you to measurement tools. If you are not deaf and have some listening intelligence then you will very soon discover what changes happen with sound while it become less self-conflicting and how to look and find those changes in  new sound. The most important is that the theory above gives (I hope) you a tool how to navigate sound objectively, by measurement and predictably toward to the DPoLS operation.

Romy the Cat wrote:

The microscopic movement and angling Rgs, Romy the Cat

unicon wrote:

I agree and understand how important is moving the speakers to find the symmetrical impulse from both channels BUT in microscopic movement we mainly correct the vibration of speakers which indeed effects the whole things. in my view the microscopic movements is bringing the luck to have both speakers vibrate in way to generate same impulses ...

It would be hard to see how at microscopic level vibration comes to the picture. It might of course offset pulse response but to a degree but the degree would be much lower than the offset by distance discrepancy. It is not to mention that feeling that vibration is on the picture would be identical to stating that vibration-prone speakers have no DPoLS dependency. I do not think that this is the case.

I do not want to jump from DPoLS to vibration subject but I feel that vibration of speaks is not a problem at all. It is the problem that it very obvious, easy to demonstrate and very easy to sell to people. Some companies build up on the fear of vibration and spend a lot of efforts to deal with it (Revel foe instance) but still end up with horrible result (that might have no connection to vibration at all). Some companies do include the presumption of vibration into the design (the Living Voice is the example, even though I do not know how they sound and some sources suggest that light and vibrating enclosures has nothing to do with sound but with LV intention to same on cross-ocean shipment.)

Still, whatever impact the vibrations have I think in phase vibrating of both speakers might be desirable. Here is what the pulses need to be read by laser with taking into consideration the distances between the listener and speakers – very interesting subject but absolutely not observed….

I still would feel that the box vibrations are no what we deal during DPoLS setting but no one can be certain about anything what we are taking about Quantum Mechanics of Loudspeakers Setup. The sad part is no one taking or dealing with this “Quantum Mechanics”. I am sure if some serious sound company would put their math and experimental recourses into the subjects then we would see a small $149.95 devise that would set find for us DPoLS very easy.