Dispelling Myths About EQ

[Duke Spinner]

Ouch .......!!!! [:$]

[mas]

And for a more complete presentation, you can access Sound System Engineering, 3rd Edition by Davis and Patronis, especially Chapters 13, 14, and 15, beginning on page 341 and continuing through page 422.

For those who appreciate that the subject by definition uses math as a promary decriptive medium, minimum phase is most easily defined as a system whose transfer functions are characterized by having all of the transfer function 'zeros' located in the left-hand (negative) side of the S Plane (or, in worst case on the imaginary axis).

But not to worry... these pages, especially the section beginning on page 381, have PLENTY of pictures. (So it must be correct!)

[ClaudeJ1]

For those who like pictures, I hope you enjoy this.

Note that the filters work great in a minimum phase environment.

Unfortunately they do not work in a non-minimum phase environment.

And neither the K;ipsch Heritage, nor room acoustics (other than an anechoic chamber) are minimum phase.

Thus, they have limited application in suc an environment.

You are right. But when you apply the right thing to the wrong thing in the right environment, it sho do sound mo betta than befo!

[mas]

You are more correctly appying the wrong thing to the wrong thing and simply changing the response!

If you are content to do things incorrectly (and yes, that is the
correct word), then hey, who am I to say you can't. But please don't
say that it is optimal. Instead you are simply choosing to settle for what you
have. But if you are looking to implement current theory and practice,
there is more. And that is the focus of the topic.

And please don't get me wrong! I listen to plenty of 'imperfect' systems and quite enjoy them! Granted, I will try to make the adjustments that return the biggest bang for the buck given the practical constraints of the moment, but I can still enjoy a system even if it is not optimal.

Instead, here we are simply trying to dispel some of the commonly employed steps and expenses that many have come to accept through legacy myths, and the indiscriminate use of EQ as a 'cure all' 'tone control' or as correction for room problems is certainly one of these problems. Here, you need not expend the extra energy and cost, especially if you are not willing to go further and measure the system for equalizable areas (if any) of the passband. Rather, if you are concerned with remediating system and room problems, there are very likely other more effective, and in some cases, cheaper, methods available. But in any case, the focus is on more effective solutions. But even no action is better than spending money and effort on a step that may simply make things worse.

What is amazing is that so many are evidently resistant to learning more about this and completely content with doing things in less than optimal manner rather than discovering what applying the right thing to the right thing in the correct environment can sound like!

I mean, I can replace a cracked windshield with a piece of 2-mil 'clear' plastic from Wal-Mart. Its not exactly clear and what can be seen looks like it is being viewed through a fun house mirror, but gee, it keeps the rain out.And some may find that sufficient. My point is not to tell you that you can't, nor that you don't like it. I am simply trying to present a more optimal solution.

But doesn't anyone even wonder how it might perform if you replaced the windshield with a proper windshield, or even another method that may perform better?

Some are happy keeping a stylus in the groove by putting a nickel on the headshell. 'Gee, it sounds fine to me.' OK...

And some are happy listening to movies through the 1.5inch integrated speakers in their large screen plasma... OK...

There is no denying the seeming plethora of less than optimal techniques used to change the performance of various processes.
And for those content with that, such topics as this will probably not interest you...

But doesn't anyone even wonder how it might perform if you used the proper techniques and technologies for optimize results???

And in many situations, you simply avoid further aggravating a bad situation as many applications of EQ do. (But again, you need to be able to identify a minimum phase application if you desire to do it properly!)

I am always amazed that little kids can wear their shoes on the wrong
feet. (And I suspect those of you who are parents can relate to this...) And when asked if it doesn't hurt, they say, "Sure"...but not so
bad they they change them. And so it is with consumer audio, and most definitely with the topic of EQ..

[sfogg]

"nor room acoustics (other than an anechoic chamber) are minimum phase."

Umm... low frequency resonances in a home environment are minimum phase.

As far as posting lots of links to papers on EQ that sort of thing is easy to do.

Probably have heard of Michael Gerzon, if not AES search him.


http://www.audiosignal.co.uk/Digital%20room%20equalisation.html

Likewise you have probably heard of Floyd E. Toole....

http://www.harmanaudio.com/all_about_audio/acoustical_design.pdf

Shawn

[mas]

There are plenty of conditions where signals are minimum phase in a live recorded SR system (as indicated in the original article). Unfortunately there are very few that are able to be productively manipulated in a playback only system in a small acoustical space utilizing horns with significant acoustic origin offsets.

The original article made an attempt to quickly run through a very simple SR environment and make a quick inventory by application where EQualization is both possible and can perhaps be used appropriately. They also pointed out several areas where EQualization is not possible nor appropiate.

The purpose of the thread was to build upon the problem that Richard Heyser pointed out in the KHorn review and to begin to provide an overview of where EQualization is, or is not. appropriate in the home environment. And the single simplest determinate criteria was the identification of minimum and non-minimum phase environments.

And while LF reflections are not as specular as higher frequency reflections, neither are they truly minimum phase. IF this were correct, there
would not be various types of modes characterized by different
reflective paths. But LFs in a small acoustical space exist in a
'hybrid space' where they behave both as 'partially minimum phase' and
partially as 'non-minimum phase' signals (and where, like the wave/particle duality in quantum, neither model is adequate). And in such an environment, other more effective tools exist that likewise provide a greater return on investment.

And in that situation, the use of a graphic or parametric equalize will neither correct for the substantial acoustical center offsets in the Heritage speakers, nor will it correct for the room anomalies.sufficient to accomplish what would be considered a sufficiently 'tuned' room.

In other words, people would be mis-served to have it suggested that a graphic or parametric EQualizer will make the most significant contribution toward improvement or that they will even provide any substantial return on investment for a playback system in a small acoustical space as they provide are neither crossover functionality, nor do they address the acoustical anomalies caused by specular reflections.. Their efforts and money would be better served by putting it elsewhere.

But for some reason you seem preoccupied with simply trying to imply that EQ can be used indiscriminately with no mention of any fundamental limitations. NOT ONE.

For every qualification of the effectiveness of EQ, a potentially legitimate use of EQ (such as the non sequitur reference to the use of FIR and IIR filters in a crossover! as if they are effective in addressing acoustical origin offsets of ~9 FEET! ...ROFLMAO) is trotted out as if providing an exception will negate the fundamental point.

Providing a limited potential use of EQ does not negate the fact that it is one of the most commonly and indiscriminately mis-applied. technologies in audio. The point was NEVER that EQ can never be used..But it cannot be used effectively in a non-minimum phase environment. And this is precisely the environment that most find dominates their listening environment.

And unfortunately, instead of acknowledging and clarifying such major limitations and helping others to understand the proper use and VERY common MIS-use of the technology and thus helping them to make better purchases and aiding them to better focus their efforts in tuning their systems and rooms, we get articles on elliptic filters (which only work in minimum phase environments - which also begs the question as to exactly what Klipsch Heritage speaker these are useful???) and implying that the use of EQ is the optimal solution for LF tuned resonances, where amplitude anomalies can potentially be reduced, but where the persistence in time, the aspect that creates the boominess is not effectively remediated; and which are better addressed with the appropriate use of traps.

If you would like to to try to address the use or mis-use of graphic and/or parametric EQualizers in a manner that most people actually employ them as suggested in the original article, be my guest. And if you have a real sense of humor, you might want to write about the attempts of some to use the auto-EQ feature driven by an RTA in a live venue! But in any case, please try to remain focused on the original topic.

And "as far as posting lots of links to papers on EQ that sort of thing is easy to do"... We've noticed. Unfortunately, understanding them is not quite as easy.

[sfogg]

"But for some reason you seem preoccupied with simply trying to imply that EQ can be used indiscriminately with no mention of any fundamental limitations. NOT ONE."

Arguing with your strawman again?

I never said EQ can be used everywhere. I stated where I was using it. Nothing more, nothing less.

"And while LF reflections are not as specular as higher frequency reflections, neither are they truly minimum phase. IF this were correct, there would not be various types of modes characterized by different reflective paths."

I said specifically the low frequency resonances of the room. I did not say any and all low frequency reflections.

"But for some reason you seem preoccupied with simply trying to imply that EQ can be used indiscriminately with no mention of any fundamental limitations. NOT ONE."

Why would I need to list the limitations? Your original article listed them. NOT ONE... because they were already mentioned. You see... unlike your numerous posts to the contrary I did read the article long before I posted anything in the thread.

My posting of how I use EQ in my system had nothing to do with the original article. It was in response to the posts basically simply saying things like 'EQ is BAD' and your posts of "the notion that EQ can correct for superposition induced comb filtering and polar lobing in non-minimum phase multi-source environments (speakers and rooms) is even more so."

Since I obviously disagree because EQ used to sharpen crossovers does reduce comb filtering and the attendant polar response changes.

The 'debate' after that point was your taking issue with what I posted. Not my taking issue with the original article, contrary to what you think.

"and implying that the use of EQ is the optimal solution for LF tuned resonances, where amplitude anomalies can potentially be reduced, but where the persistence in time, the aspect that creates the boominess is not effectively remediated"

I didn't say it was the only solutions, I said it is something I use to deal with room resonances. Did you actually read the Toole article? EQ does help reduce the decay time of the room resonances if you use the EQ to deal with the resonances alone. Meridian and Lexicon both take this approach with their systems for example.

You will also note neither system tries to do anything beyond the bass range. Meridian's limits itself to 200hz and below, Lexicons to 250hz and below. The reason for that we can both agree on...... (well maybe....) And both setup their filters directly based on resonances within the room by measuring decay time, not amplitude response.

Shawn

[mas]

So it seems that the big distinction is over what constitutes an "equalizer". And here I was trying to facilitate a discussion regarding the appropriate use of the device instead. Funny, it seems to me that the many folks on the forum, when they refer to buying or using an equalizer ,seem to have no problem with confusing a crossover with an equalizer. And to my knowledge, I have not noted anyone wanting to employ any of the after market crossovers so frequently mentioned here, as an inline equalizer. So my erroneous assumption was that the most of the folks here understand the distinction. Obviously I was wrong. ...and talk about 'strawmen'...

Your insight regarding steeper slopes began as a given solution in the article. But they did so by employing a 'crossover' (more on that later, as they specifically advocated dumping the passive crossover), or what is increasingly being referred to, due to its increasingly sophisticated role, as a "processor". It was not accomplished by employing what is commonly known in the industry as a 'equalizer', of which the most common forms are "graphic" and "parametric", and where "to EQ" is reference to the action of employing and adjusting the "equalizer".

But then Davis and Patronis also suggest a simple distinction for the use of the words, one that is readily accepted in use in the industry: "Perhaps we should separate electroacoustical transducer magnitude and phase adjustment from other forms of signal processing that are quickly coming on the scene (e.g., signal synchronization). If we were to reserve the word "equalizer" for those devices that made system gain equal at all frequencies and used "signal processor" or "adjuster" for those devices intended to shape specifically the transfer function of the system for any purpose other than optimum acoustic gain, we might forestall at least a little confusion". p.415, SSE

Who would have thought that the fundamental issue should have been addressed in an English class.

The article is very specific in the reference to externally applied equalization ("EQ") performed by the system operator via the insertion in the signal chain of a device known as an "equalizer".

Trooper specifically draws the distinction between a graphic or parametric 'EQualizer' and a crossover in his reference to the use of equalizers versus the processor modules integrated into powered speakers. And he specifically refers to EAW's processors. Perhaps his error was in assuming that the reading audience understands what companies such as EAW are doing. The irony is that most of the pro market, with whom this discussion was originally conducted, do understand. And unlike on this forum, no debate over the use of the terms ensued. And, similarly they do not employ 'equalizers' to tune interdriver interaction.

Jim Brown specifically begins by stating that the goal is to properly
design and configure the system to be as flat as possible by addressing
both physical aspects of the room and system as well as source origins
"whether that EQ is in the manufacturer's processor or not." He likewise acknowledges legitimate points where minimum phase equalization may be employed - and it should be noted that few if any of these user configurable stages are available to the user of a playback system.

It seems to me that even before your insight that steeper slopes can be employed (despite the fact that passive crossovers, regardless of slope - and we have not even touched on the potential problems introduced by high slopes! - cannot provide the optimal adjustment that is needed) that the subject had already been addressed by both. Of course their references assume an understanding of the underlying principles as well as the common meaning and usage of the terms equalizer and crossover and processor. And it is there that one might have expected a few questions by others if they were not as intimate with them.

But to argue that a crossover is an equalizer and to attempt to redefine the common usage of industry standard terms? Who would have thunk it here!

It will be interesting to see if your convention of referring to what has been commonly called a 'crossover' of 'frequency dividing network' as an 'equalizer' catches on. But I suspect that you can expect the support of the textbook industry who is always looking for a reason to release a new edition and render the old editions worthless for textbook buyback!

The distinction of note is that crossover networks, or frequency dividing networks, and filter design are not commonly referred to as "equalizers" or even as "equalization", although they may employ all sorts of waveform shaping functions! And the devices sold under the label "equalizer" are not intended for serve as a frequency dividing network. That is the reason the term "crossover" is commonly employed. And likewise, "crossovers" are not commonly used to be inserted into the signal chain to modify the amplitude of a passband signal where multiple transducers are not being employed.

Rather than refer to everything in the signal chain as an 'equalizer' for its potential to alter the amplitude of various aspects of the signal, the terms are commonly used in a more discriminatory manner. So much so that if I walk into the average MI store and ask to be shown a crossover or an equalizer, even the newest clerk can reasonably make the distinction.

Both the article and I made chose to use that commonly used distinction. Thus the article even employed a graphic equalizer in the title graphic. And the article referred to avoiding the passive crossovers in lieu of using active crossovers with signal alignment (a function 'normally' integrated in active crossovers) used in conjunction with bi/tri-amping (bi-amping being the most commonly used term simply because most monitors and even SR stacks are 2 way and do not employ a separate tweeter.)

The fact remains, that the use of what is commonly known as an "equalizer" has very limited positive use in a playback system. Its use is limited to the non-minimum phase regions of the spectrum (and most do not have the means to determine those regions as they commonly require measurements performed by time domain based measurement systems such as TEF, EASERA or SMAART.) And equalizers are not useful in correcting the room anomalies created by non-minimum phase specular reflections, comb filtering, and polar anomalies for which many have tried, and continue to try, to use them.

In electrical terms:

"The equalizer's transfer function must have zeros for the troublesome poles and poles for the troublesome zeros. Recall that for physically realizable systems, however, the poles must be in the left half of the S plane. Therefore if the original system happened to have a troublesome zero in the right half of the S plane, which it could have if the anomaly were non-minimum phase, it would be impossible to cancel this zero by a superimposed pole. Therefore such a system could not be truly equalized. If one were to attempt to experimentally equalize a non-minimum phase system by, say, flattening its amplitude response, this process would introduce violent behavior in the phase response and visa versa. The process of equalization is restricted to minimum phase shift systems.

When equalization is applied to correct anomalies in minimum phase systems, the correction in amplitude and phase behavior go hand in hand and will occur simultaneously. Equalization should only be applied to minimum phase systems and even when it can be employed, it must be employed with care so as not to force any subsystem beyond its range of linear operation" p.381, Sound System Engineering, 3rd Edition

And it is to this subject that the article, and the thread was intended.

PS: Into to Chapter 15, Sound System Equalization:
"The Original one-third octave band rejection filer set utilizing summing circuitry was first used by one of the authors in 1967 and the patent 3,624,298 was files in March 1969 and issued on November 1971. Since its inception the basic problems of its correct use have been two fold: first, the ability to design a sound system capable of benefiting from the use of an equalizer, and second, the attempt to equalize the unequalizable. These problems are with us more than forty years later.
...
Equalization can't solve loudspeaker coverage problems. Equalization cannot align speakers. Equalizers can't raise acoustic gain unless the system has adequate power available to support the gain increase. Equalizers are of no use in controlling reverberation, discrete echoes, etc.

Careful practice can minimize aggravating these problems via regeneration through the sound system. An equalizer can adjust the direct sound pressure level of the loudspeaker's minimum phase output frequencies. This is accomplished by providing the conjugate amplitude and phase response to any minimum phase aberrations in the loudspeaker's direct sound level, Ld.

Proper equalization adjusts both amplitude and phase to a more uniform response. A delay in microseconds is introduced by the insertion of the filters. The measurement of both amplitude and relative phase is essential in the process of equalization. Group delay for a record can be years. The delay through some adaptive digital filters can be appreciable, +- 30 ms.

The triumvirate of proper equalization, signal synchronization, and seamless coverage is a very powerful tool used to create extraordinary sound quality..." p.401, Sound System Engineering, 3rd Edition

If you would like all of the in depth details, complete with LOTS of pictures (as some have already expressed how important they are...but be forewarned, you have to supply your own crayons...), may I suggest getting and reading the book.
Oh, and as a complete aside, as I have meant to address this on several other occasions, diaphragmatic behavior of wall surfaces ('wall resonance') has been mentioned as a concern by others, especially Michael. You will be glad to know that this subject is addressed in detail as well, complete with techniques to identify and isolate such problems..

[Duke Spinner]

Ooooohhh ..... Double ....Yeeeouch .... !!!

[sfogg]

"So it seems that the big distinction is over what constitutes an "equalizer". "

You have already tried this approach... remember.

There is no big distinction at all. I am using parametric EQs to alter the slope of a crossover.

No more, no less. You just can't accept that.

"Funny, it seems to me that the many folks on the forum, when they refer to buying or using an equalizer ,seem to have no problem with confusing a crossover with an equalizer....So my erroneous assumption was that the most of the folks here understand the distinction."

The only person that seems so confused is you. For a guy spouting so much talk about bi-amping a system with delay one would think you would have had some slight amount of experience with the digital units that combine both crossover and EQ functions within the same box. Obviously I was wrong thinking that you knew about these boxes... since you don't know they allow one to apply parametric EQ to the outputs of the crossover functions in the boxes. In other words when one is bi/tri-amping with one of these boxes the boxes give the user parametric EQ functions to are specific to each output/driver in the system.

A combination of the crossover and the parametric EQ allows one to get (much) steeper crossover slopes which as you have confirmed and the original article also states reduces comb filtering and the polar problems between drivers.

"Your insight regarding steeper slopes began as a given solution in the article."

I know!!!

Which is why your continued arguing against what I'm doing is insane. One day you argue for it, the next against it. Flip flop... flip flop....

Decide what position you want to take and show some consistency.... ok?

"But to argue that a crossover is an equalizer and to attempt to redefine the common usage of industry standard terms? Who would have thunk it here!"

No one is doing that except you. I turn on the PARAMETRIC EQ function in my digital units and my acoustic crossover slopes get *dramatically* steeper. I turn off the PARAMETRIC EQ function in my digital units and the acoustic crossover slopes get much shallower. I have already demonstrated how to do this and told you *exactly* what the settings of the PARAMETRIC EQ were set to. Yet you want to redefine things and pretend the parametric EQ isn't really EQ....

The difference in comb filtering while listening to pink noise and walking around the room is plainly audible. And as I have stated *many* times it is the PARAMETRIC EQ that is being applied on the outputs of the crossover section that is making that difference.

But please keep sticking you head in the sand and ignoring this.

One is talking from the perspective of experience, one is talking from the position of ignorance.

"The fact remains, that the use of what is commonly known as an "equalizer" has very limited positive use in a playback system. Its use is limited to the non-minimum phase regions of the spectrum..."

I think you are confused again... you have been arguing that equalizers are limited to the minimum phase regions of the spectrum.....

Shawn

[mas]

One is talking from the perspective of experience, one is talking from the position of ignorance

EXACTLY! And what do Davis, Patronis, Danley, Rayburn, Keele, Berger, Brown, Carey, Todrank, and a much longer list of prominent ignorant physicists and acousticians know? Gee, I only had the opportunity to study with them and to share in experiments with them coupled with far too much practical experience combined with even some book learnin.

And gee whiz, I just bought my first speaker, and it ain't jest a speaker, it comes with a 3 transistor digtal radyo too! And it even has a tone control! Its the deeelux model! I think you call it an 'ekwelizr"! So I'ze qualified. And just out of curiosity, he asked, what is that "digital unit" of yours called?" It wouldn't be some sort of "processor" would it? Gee, but we addressed this too, but you failed to take that comment out of context as well. And with luck its probably made by the 'new' dbx. Their DSP programming is getting rave(sic) reviews. But at least they are relatively cheap.

.

... you have been arguing that equalizers are limited to the minimum phase regions of the spectrum...

Yup! Just like them other ignort folks that you know more than! And you still fail to grasp this.

I only wish that I could claim credit for the concepts!

You know, what is arrogant, isn't posting information that has been scrutinized and accepted in the audio field that others may have not had the opportunity to be privy too. What is arrogant is coming along and declaring those who are MUCH more accomplished and respected (of which i will simply claim to be the messenger) as being "ignorant".

But since you delight in calling me names, and yet Amy chastises me if I respond (well, because a little bird chooses to run to complain to her as they SO often do!), I will gladly let someone such as Coytee or Groomslake independently scrutinize our resumes and experience if you feel we are too ignorant for you.

But one wonders why you do not simply start your own thread if you are SO much smarter and experienced than I? But then, unless the search function is simply malfunctioning again, I don't see to many threads where you have offered much in the form of original or second hand knowledge. It seems to me that the last time you appeared was to offer a left handed description of polar lobing utilizing anything but standard geometric descriptions.

So how about it. Start your own thread that we can ignore and you can demonstrate how your processor's filter adjusts slopes of your passband.

To repeat:

The fact remains, that the use of what is commonly known as an

"equalizer" has very limited positive use in a playback system. Its use

is limited to the non-minimum phase regions of the spectrum...

Changing the slope and the overlap of two significantly mis-aligned non-minimum phase does not correct comb filtering or polar lobing. And the resultant phase error introduced causes yet additional problems. But you persist in the mistaken notion that if the comb filtering and polar lobing are changed, that this is equivalent to fixing the problem! This is exactly what was argued in defense of classic EQ from the inception of the issue! This is like going back in time and reliving 1988 all over again. Next we'll have to listen to Duran Duran.

If you want the math and a more complete discussion as to why, its available, beginning with the 3rd Edition of Sound System Engineering. And if desire to call the authors ignorant as well (in addition to the previous effort), I can refer you to them. My only additional request is to be present when you do so! I could use the laugh. But you see, for the average forum member, they seem to recoil from references to math. And as such we have tried to refer to simplified statements and conclusions rather than in depth mathematical DSP theory which I doubt would add much for them, as they are simply not interested. And as you are so much more knowledgeable and experienced than the authors, (ROFLMAO), I doubt you would gain much, although not for the same reason as the others.

So go and debate Davis and Patronis and Danley and Brown the other "ignorant" folks of which you know so much more. I can get you a few addresses, and I could also provide you with some phone numbers (if that would not be doing them such a dis-service!).Your points are non sequitur and already addressed most saliently in the opening article. You have added little but noise, and a bit of perverse 'retro' entertainment on a few slow afternoons.

Unfortunately you have added little to the clarification of a subject that remains a continuing problem, at least according to many prominent industry figures who you dismiss as "ignorant". I will be sure to pass on the information when I next speak to them. You can join the line of folks who thought so as well. And while you are there, say "hi" to Lipshitz and Vanderkooy.

And please, find another person's thread that you can attempt to hijack and who you can attack personally. After all, I and my sources are just too "ignorant" for such an erudite authority as yourself. There just must be a thread debating exotic interconnects somewhere just begging for your contribution...

Its too bad that I can't locate a virtual fly paper that would work here...

[DrWho]

So mas, what is the point you're trying to make? That EQ should never be used? Surely you don't glean that from that one article, or SSE, or anything else from SAC???

[Duke Spinner]

Who ..

i think You have missed the salient points discussed here as regards to EQ, and phase [:|]

[DrWho]

I just wanted to clarify before I go about citing the author's of his sources that actually advocate the use of EQ...

[Duke Spinner]

ok... Who ..

let's have it ...[]

[mas]

So mas, what is the point you're trying to make? That EQ should never be used? Surely you don't glean that from that one article, or SSE, or anything else from SAC???

Where have I ever said or implied that EQ can never be used?

EQ can be used successfully in minimum phase situations****** . This fundamental limitation is critical to understand in system design and it is one of the most frequently ignored aspects of system. And this ranges from the use of passive crossovers in speaker design, to the treatment of rooms.

The irony is that many of the most common 'places and situations' where many attempt to employ EQ in their home sound system are also the wrong 'place/situation'. Ranging from reaching for the EQ to flatten the KHorn's direct signal frequency response (now why isn't that minimum phase?) to correcting listening position responses when what you are actually addressing are non-minimum phase room response anomalies.

Also, the ability to determine the minimum phase regions where EQ is possible for a system within a room is much more difficult to determine than most realize without the appropriate tools

Understanding the conditions and factors that make equalization difficult are fundamental to a larger more encompassing understanding of the acoustical environment, and they open a door to a much larger view and more comprehensive understanding.

It would also be nice if more would choose to understand conditions that contribute to non-minimum phase 'situations' and the ramifications of those characteristics, and understanding this, might then further pursue techniques that are more effective at resolving such problems.

And to go further, when was the last time there was a serious discussion oriented around signal synchronization, the challenges to achieving such a state, and the advantages such an accomplishment achieves? And, for instance, after two postings of the Heyser KHorn review, how many are still questioning Heyser and the validity of his review rather than examining and looking for valid methods to correct what his review correctly indicated?

How's that for a start?

And perhaps its too much to expect, but I cannot help but imagine how much fun it would be if the current paradigms in acoustics were better understood and topics here were addresses with a greater common understanding facilitating a more lucid discussion of the problems based upon valid principles and a greater realization of the potential solutions and subsequent listening pleasure. Yeah, I know...but its my fantasy.

****** {EDIT: TYPO ALERT: this should have been: "minimum" phase...: The fact that I have only said it ~1000 times already has poor Shaun thinking I have auddwnly changed my position or that of the quoted sources! I mean, is that the best you can do?! ROFLMAO!|

[Coytee]

Ok, time for me to admit being a dummy again....

What, if I may ask, does minimum phase, non-minimum phase reflections mean in SIMPLE terms?

I'm sure there's at least ONE other person on this forum who's as clueless as I am. (at least I hope so!! [*-)])

[DrWho]

If that's what you're really trying to say, then I really don't understand your beef with everyone in this thread.

[sfogg]

Jumping away from trying to redefine a parametric EQ as not being an EQ I see....

"Changing the slope and the overlap of two significantly mis-aligned non-minimum phase does not correct comb filtering or polar lobing."

Make up your mind.... seriously..... literally the post before this one you posted....

"Your insight regarding steeper slopes began as a given solution in the article."

Flip flop... flip flop....

"Yup! Just like them other ignort folks that you know more than! And you still fail to grasp this."

Did you read what I questioned you on? You obviously didn't read it very carefully since you said you can only use EQ in non-minimum phase areas of the spectrum. You repeated that same position again in your latest post. Read it again.... now read it another time.... one more time.... do you see it yet?

Just in case you missed it... in that post your quoted others with the following:

"When equalization is applied to correct anomalies in minimum phase systems, the correction in amplitude and phase behavior go hand in hand and will occur simultaneously. Equalization should only be applied to minimum phase systems and even when it can be employed, it must be employed with care so as not to force any subsystem beyond its range of linear operation"

And

An equalizer can adjust the direct sound pressure level of the loudspeaker's minimum phase output frequencies.

In other words they are saying to limit EQ use to minimum phase.

Yet your own words in that post say this....

"The fact remains, that the use of what is commonly known as an "equalizer" has very limited positive use in a playback system. Its use is limited to the non-minimum phase regions of the spectrum..."

Two quotes saying minimum phase.... you saying non-minimum phase and repeating that again in your latest message.

So like I said...

I think you are confused again... you have been arguing that equalizers are limited to the minimum phase regions of the spectrum.....

get it?

So your response of my question this of:

"Yup! Just like them other ignort folks that you know more than! And you still fail to grasp this."

Is fairly funny since you are saying the exact opposite of your sources.... who exactly is the one failing to grasp this?

"So how about it. Start your own thread that we can ignore and you can demonstrate how your processor's filter adjusts slopes of your passband. "

Been there.. done that. So much for your search....

Shawn

[mark1101]

Shawn,

Did you mention that your EV DX-38 also does time alignment of outputs and phase shifitng besides para EQ and active crossing? Not sure if I saw it and I'm too lazy right now to go back and see.