Above the Schroeder Frequency. Diffraction.

[Seamus TM]

Wow.
That is crazy.

[PaulP]

Originally Posted by Lupo

My room is 2300 cubic feet, BTW.

So not that small, which helps enormously.

Low end treatment is another issue.

Which you continue to sidestep, just like your prophet.

If someone can explain to me how the other graphs are directly useful in the way ETC's are, I'd much appreciate it.

They're useful for the low end, as you yourself point out.

I get the feeling you've fallen into a well-layed trap. I hope that you will
get the chance to work on a truly small room sometime. And, just like SAC,
you have provided very little in the way of hard directions in measuring a
room. I have a feeling most of the testing you describe was done in your
head. Sorry for being blunt.

Paul P

[johndykstra]

Originally Posted by Lupo

It's obvious that the wrapping of this issue have been inedible to some. Hope the insulted doesn't let it hinder them in their quest to know more. I do strongly believe there is something to gain here for everyone! It's just a tool. It doesn't have any emotion in itself. Look at the message, not the messenger.

Andreas

Andreas,

Thank you so much for your explanation. I've never had a problem with the message.

[johndykstra]

When speaking of the -20db for reflections, is that the target for specular reflections AND diffuse reflections, or is there a seperate target? And if you do shorten your ISD gap (I think I understand now) should you also have a lower target for a reflections gain?

Forgive me if this has already been stated, but this thread is over 8 pages. Not really going to be the most concise topic at this point.

[Nordenstam]

Originally Posted by PaulP

So not that small, which helps enormously.

The proportions are quite nice as well.

That's beside the point here. All of our rooms fall into the small room category when it comes to acoustics! It really doesn't matter what size the room is. Honestly! The level of each reflection will still be possible to measure, independent of small or large.

It's no different than looking at frequency response graphs like this:

(chose that image because it reminds of the ETC's! :D )

But instead of scanning left to right from bass to high end, ETC's shows energy vs time. It is what it is, a measurement tool. If you're checking gear, you'll use both frequency response and THD measurements. One doesn't exclude the use of the other.

Originally Posted by PaulP

Which you continue to sidestep, just like your prophet.

It's not part of the ETC ordeal, it's a different subject. If you want to discuss low end treatment, I'll participate if I can contribute anything. My knowledge regarding the issue is highly limited. That's why you wont find me contributing much if anything at all in the umpty threads on the subject.

Originally Posted by PaulP

They're useful for the low end, as you yourself point out.

Yep. At least we can agree on something! :D

Originally Posted by PaulP

I get the feeling you've fallen into a well-layed trap. I hope that you will
get the chance to work on a truly small room sometime. ... I have a feeling most of the testing you describe was done in your
head. Sorry for being blunt.

It's not about prophets or religion. It's a measurement tool that works for determining actual real world events. I use multimeters, SPL meter, oscilloscope, crosstalk, freq response and THD measurements, observe sweeps in spectrum editors to watch for aliasing in digital, think waterfalls are excellent for low end observations in a room and I use ETC's for checking the level of individual reflections. I've done it in my room and I'll do it in a shoebox if needed. The waterfall does not give the same detail as it's weighted towards frequency discrimination, not time discrimination.


Some diffusers on the rear wall:


More diffusers on the same rear wall:


The rear reflection comes around 20ms. There also some other things happening in the comparison, please disregard that. The point is to illustrate that its' not just theory.


Not so smooth overall decay response:


Smoother response:


These pics are NOT made to be easily grasped examples. It's a response to the "pics or it didn't happen" insinuation. Haven't been doing any measurements with the explicit goal to prove any point.

Don't see that it would be different to work on a truly small room. There would still be modal issues and there would still be reflections. We use the treatment we choose and we use the measurement tools appropriate to determine the effect of using the treatment. That's it. No magic trick.

And, just like SAC, you have provided very little in the way of hard directions in measuring a room.

Sorry if I'm being dense now. What is it that you want? I realize it's a too open question, but so is yours.

I can't see much else to add to it. Reflections have energy. ETC's shows the energy for any given reflection. If one wants to absorb that energy, one can check how much energy is being absorbed by using an energy level meter like the ETC. The reason to use the overall ETC picture to evaluate the listening quality is because it corresponds well to how the ear works. Haas zone, spatial localization and all that stuff are concerned with the time/energy relation of sounds.


If this is once again read as the deluded ramblings of a religious follower, please give me a word and I'll drop it. I'm not doing this to convince anyone of a belief.

[Nordenstam]

Originally Posted by dykstraster@gmai

When speaking of the -20db for reflections, is that the target for specular reflections AND diffuse reflections, or is there a seperate target? And if you do shorten your ISD gap (I think I understand now) should you also have a lower target for a reflections gain?

As far as I've gathered, -20dB is a good general starting point. The specular ones are easier to detect than diffusers, so you may take that into consideration.

Have a hunch shorter ISD would call for a higher level in the Haas kicker to be heard, but I don't know..

[johndykstra]

Ok, so here's where I show my ignorance. I pose this question here, as opposed to in the room analysis primer, because others here seem to be more in favor of ETCs.

I've never used any room analysis software.

I would like to only learn a platform once, and I don't mind paying.... to a point.

Can I get everything I need from REW, or should I look into Fuzz measure... or perhaps something else? I would like to have the functionality of a waterfall plot as well.

[PaulP]

Originally Posted by Lupo

It's not about prophets or religion.

Andreas, I really don't want to be a pain in your neck, but your behaviour
is that of one who has lived a religious experience. I know you're excited
about finding a new way at looking at things, and discovering a new tool,
but you don't have to get down on your knees and kiss the feet of the
person who opened your eyes. Especially when that person is very disruptive
and unhelpful, and treats everyone like trash.

It's all quite annoying .

More so since I was also guilty of the same behaviour.

Anyway, you were saying...

It's a measurement tool that works for determining actual real world events. I use multimeters, SPL meter, oscilloscope, crosstalk, freq response and THD measurements, observe sweeps in spectrum editors to watch for aliasing in digital, think waterfalls are excellent for low end observations in a room and I use ETC's for checking the level of individual reflections. I've done it in my room and I'll do it in a shoebox if needed. The waterfall does not give the same detail as it's weighted towards frequency discrimination, not time discrimination.

This is a better picture and shows the ETC in it's place, that of tracking down
reflections, which is only a small part of treating a room. This thread is not
about the ETC, though you-know-who turned it into that, as is his habit.

The waterfall was never supposed to do the job of the ETC and no one has said it should.

About the lower frequencies, you said (I've moved your comment) :

It's not part of the ETC ordeal, it's a different subject. If you want to discuss low end treatment, I'll participate if I can contribute anything. My knowledge regarding the issue is highly limited. That's why you wont find me contributing much if anything at all in the umpty threads on the subject.

The thing is we're interested in treating our rooms. That means all the
frequencies. Mumblesound was/is interested in a particular band fairly far
down the range. The ETC may or may not be useful here, but if we sidetrack
the discussion to talk about it, we should do so in the proper context, that
it is only a small part of the picture. I've been objecting to the ETC being
promoted as the only tool necessary and worthy of our consideration, regardless
of context. I'll continue to do so to protect any new innocents who come along.

But since we have ended up talking about the ETC...

Some diffusers on the rear wall: ...

More diffusers on the same rear wall:...

Good ! The only way that makes sense to me (and probably a few others around
here) to discuss the ETC is to provide examples of both graphs and the
methodology used in acquiring and interpreting them. Real world examples.
How about your room since you've made yourself spokesman for the subject ?
(I promise I'll be exposing the testing and treatment of my room once I start).

These pics are NOT made to be easily grasped examples. It's a response to the "pics or it didn't happen" insinuation.

That was the intention, we've had enough of dogma.

Don't see that it would be different to work on a truly small room. There would still be modal issues and there would still be reflections. We use the treatment we choose and we use the measurement tools appropriate to determine the effect of using the treatment. That's it. No magic trick.

Except that it still hasn't been done by anyone. Those few brave souls who
did post the test results for their small rooms were completely ignored.

If this is once again read as the deluded ramblings of a religious follower, please give me a word and I'll drop it. I'm not doing this to convince anyone of a belief.

I don't want you to drop it, I just want you to come back down to earth .
I really enjoy reading your posts, all of them. You inject a lot of knowledge,
experience and energy into the discussions we have here.

Paul P

[PaulP]

Originally Posted by dykstraster@gmai

Can I get everything I need from REW, or should I look into Fuzz measure... or perhaps something else? I would like to have the functionality of a waterfall plot as well.

I think it all depends on the accuracy and resolution of the different products,
something that may not be easy to determine. Personally I've opted for REW,
it being free had a lot to do with the intial decision, but I also find it to be a
superior 'looking' product, it's got the best interface of any software I've seen.
It appears to be complete (I'm not the best person to determine this) and
it's easy to use.

There's a whole forum dedicated to the use of REW over at the Home Theater Shack.

Paul P

[PaulP]

Mumblesound, how about starting a new thread with your original question
repeated ? After the stampede I fear no one knows what it was any more .

Sorry for my participation in said stampede.

Paul P

[Seamus TM]

Originally Posted by PaulP

Mumblesound, how about starting a new thread with your original question
repeated ? After the stampede I fear no one knows what it was any more .

Sorry for my participation in said stampede.

Paul P

That's cool.
Stampedes are a form of transportation from one place to another.
I think that my original curiosity was satisfied on the first page, honestly.
There were lots of other interesting ideas brought up in the following 7 pages.
Some bickering, some whining, some childish rantings, as well.
All and all, I think it was a positive trip.

Thanks to all.
I, for one, am looking forward to trying out an ETC program in the future.
Why not?

[Nordenstam]

Originally Posted by PaulP

Andreas, I really don't want to be a pain in your neck, but your behaviour
is that of one who has lived a religious experience. I know you're excited
about finding a new way at looking at things, and discovering a new tool,
but you don't have to get down on your knees and kiss the feet of the
person who opened your eyes. Especially when that person is very disruptive
and unhelpful, and treats everyone like trash.

Haha! That's clear cut feedback. Thanks! Chuckle.. No, it wasn't a religious experience. It's just the good old gearslut joy of having a new tool to play with! Did my first meager attempts at acoustic measurements some years ago. Started out with a dynamic mic, paying attention to low end only. It worked well enough to show relative differences down there. The other graphs told me nothing. Bought the RplusD/ETF (calibrated SDC)mic+pre+software kit last summer as the diffuser build rolled on. Thought I'd finally get something useful covering the frequency areas of imaging. Got disappointed. Was still nothing actually useable up there above the low end. Until the ETC talk came along and showed me what sort of user error it was! So, it's like I've had an EQ for months before learning how to disengage the bypass on the upper bands. That makes me a happy camper!

Dykstraster: Am using both RplusD/ETF and REW. Both works fine. RplusD works better for some things, is deeper, though a bit clunkier in the interface. REW is nice to look at and we all know that makes a difference. The ETC graphs in my previous post came out of REW.

As for feet kissing, please go back and reread what I wrote. It seems to me that's a personal interpretation a bit beyond the phrasings that was actually being used. Saying yay to ETC's doesn't mean that I'm a fan of aggressiveness, whoever it comes from. It takes more than one person to have a brawl..

Being an optimist, I'm assuming that everyone is trying to their best ability in whatever they do. It's obvious that not everyone have as much capacity as one might desire when it comes to compassion, patience, friendliness etc. It's not exactly surprising. It goes for all of us! We're ordinary humans, not Dalai Lamas. I'm easily lost as well. Not in this debate though, as I have nothing personal invested in this in any way. Wish I could keep as calm regarding other things in life.

Originally Posted by PaulP

I've been objecting to the ETC being
promoted as the only tool necessary and worthy of our consideration, regardless
of context. I'll continue to do so to protect any new innocents who come along.

It'll be an easy job. As far as I've seen, that claim has not been made.

Originally Posted by PaulP

Good ! The only way that makes sense to me (and probably a few others around
here) to discuss the ETC is to provide examples of both graphs and the
methodology used in acquiring and interpreting them. Real world examples.
How about your room since you've made yourself spokesman for the subject ?
(I promise I'll be exposing the testing and treatment of my room once I start).

Been meaning to get to it, but it takes too much time compared to the fun factor.. .. One day!

And.. I don't want to be spokeman on the subject, please. Trying to avoid potential trouble.


Woke up today and had an aha! moment. Not the pop group, thank god, it was in regard to this subject. Think I see what the misunderstanding is about. Have a feeling you and Dan want a description ala this: RealTraps - How To Set Up a Room - am I right in this assumption?

The ETC talk have not and will not procure forth such a step by step guide to room treatment complete with placement of traps. It's not like an electronic schematic for a particular piece of equipment. Rather it represents an observation concept akin to THD measurements. No matter what sort of electronics you want to build, you'll have to use THD measurements to get it right. It will very possibly change practical aspects of the design but it will not tell you anything about the design in itself. ETC's span a bit wider than that though. If you go about suppressing the first 20 milliseconds, the usual suspects (side walls, cloud, SBIR) have been automatically covered in the process. You may start in the other end, by treating those points and observe the effect on the ETC, and it'll still get to the same end result. The difference is that the ETC way caters for any and all situation, including the odd multiple reflections that may get back to the sweetspot within 20 milliseconds. The general first reflection point treatment may miss those. ETC's will also tell if each individual piece of treatment have been successfull in its designed task.

Originally Posted by PaulP

That was the intention, we've had enough of dogma.

Well done. Played me like a puppet! How high do you want me to jump? :D

Originally Posted by PaulP

Except that it still hasn't been done by anyone. Those few brave souls who
did post the test results for their small rooms were completely ignored.

Some day when I'm bored I'll treat the toilet just to prove the point. Hehe.. Seriously, I think you've seen it done already in slightly larger scale than your room. (you've mentioned 3x4x5 meters in a post way back. that's only slightly smaller than mine!) Acoustics doesn't change as the room shrinks from some thousand to thousand cubic feet. If you're in such a small box, we all know you have to trap the hell out of it and take a meditation class to avoid claustrophobia!

Had a look in MHoA. In the fifth edition, it's in chapter twenty - acoustics of control room, under the heading "initial time-delay gaps in practice". It shows, amongst other things, a D'Antonio designed very small room with a clean cut ISD of 10 millisecs. In chapter twenty one, there's a description of a voice over booth with an even smaller ISD. Chapter twenty four covers the use of ETC measurements using ETF as an example.


Glad we can talk without foul words. Lets give it good try at keeping it that way, everyone, please?


PS: a big hug to those who manage to draw something useful out of this mess. You're the best!


Cheers,

Andreas

[PaulP]

Andreas, I was a bit hesitant to open your post... thanks for not tearing me apart .

I'd like to make just a small clarification. I wrote :

Originally Posted by PaulP
Except that it still hasn't been done by anyone. Those few brave souls who
did post the test results for their small rooms were completely ignored.

To which you replied :

Originally Posted by Lupo

Some day when I'm bored I'll treat the toilet just to prove the point. Hehe.. Seriously, I think you've seen it done already in slightly larger scale than your room. (you've mentioned 3x4x5 meters in a post way back. that's only slightly smaller than mine!) Acoustics doesn't change as the room shrinks from some thousand to thousand cubic feet. If you're in such a small box, we all know you have to trap the hell out of it and take a meditation class to avoid claustrophobia!

I was not talking about myself. I have only run a single test on my (completely
untreated) room just to get REW working. I offered the test results a while
ago in one of the first discussions on the ETC just so that we could see
what was being talked about.

Subsequent to this a few members here performed tests on their rooms and
posted the results presumably so that those promoting testing of rooms
would jump in and give them advice. There was little, if any, response.
I found this disappointing.

Paul P

[Nordenstam]

Originally Posted by PaulP

Andreas, I was a bit hesitant to open your post... thanks for not tearing me apart .

The golden rule and all that.

Can I come with some criticism, without joining the war? Some personal observations? Have been continually surprised by the folks in this forum lately. Some for their (lack of) conduct and some for their ignorance and lack of willingness to learn. I do hope Sac sticks around to teach those who want to learn. Haven't seen one single factual error in his writings and I can't say the same for the rest of us. <- Us, as in including myself. Not a holier than thou thing! To be honest, it feels like we're getting out of the dark ages with regards to acoustics..

Did an interesting thing. Wanted to see where it started. This is the first post I found where Sac expounded the same old issue: Stopping early reflections
It's an interesting recap, as it shows the exact same info that have been going over again and again, most recently in this thread. It also have the same questions that some, unfortunately, feel have been left unanswered. And.. Most importantly: it shows a civil conduct from all parts involved! If it only had stayed that way. Something went awfully wrong after that. Sincerely hope we can all forget about that silly mess and get on with it.

Originally Posted by PaulP

Subsequent to this a few members here performed tests on their rooms and posted the results presumably so that those promoting testing of rooms would jump in and give them advice. There was little, if any, response. I found this disappointing.

Can see why you're disappointed by that! Have also been hoping for more practical illustrations. Shrug.. DIY or die.

Edit PS: interesting text showing how ETC's are used to produce more realistic voice overs: Using time domain measurement methods for audio production applications

[SAC]

Lupo, it is easy to verbally jump from analyzing a response (i.e. identifying individual reflections and their attributes) - of which one stated that the frequency response and RT60s should be sufficient for analysis and refused to generate ETCs! - to treating a room! Of course, others have complained that the ETCs do not cure room modes. A case of using the right tool for the job. And the process has been curtailed in large measure as some individuals have either been unable to generate the ETCs, or unwilling to pursue the methods of evaluating the individual reflections. One has. But to my knowledge, I am not sure what options they have decided to pursue in addressing identified issues.

But in any regards, identifying individual reflection behavior and subsequent 'room tuning' are TWO different processes! Related? Sure! But not necessarily the same. Just as taking the temperature and performing open heart surgery are related, but simply having a tool does not imply that one can simply demand "the answer" and perform the other. One is a step in the process of learning more in order to do the other.

And its been like pulling teeth to simply get many to become aware of the ETC and that it is useful. And also that it implies a VERY different point of view on the world of acoustics from what many have ALWAYS been accustomed! We are no longer in the Flatland of the frequency response.

And this has been a recurrent problem here!

We are dealing with what is necessarily a process, not some static one size fits all solution that you simply order in red or blue. And while part of that process may involve discussing and referring to General models, but it also necessarily involves evaluating each space individually to see how each particular space behaves relative to the generalization. And from this, one may determine the best set of options to achieve a desired end.

The thinking process must change.

Once an ETC is generated, the interest in doing the mundane trivial work of evaluating each reflection (which, granted is not glamorous!) is quickly abandoned and the demands quickly change to - well, you didn't tell them exactly how to treat their room - as in "what is THE answer" - so the measurement and process are quickly determined to be invalid.

Identifying and addressing early reflections that result from enclosure or speaker shelf mount diffraction is 'easy'. But so is the mantra of "MORE ABSORPTION" which has become an automatic conditioned response here, although it presents a potentially conflicting scenario that is not necessarily optimal. A more tempered response is in order.

And for those who will jump in to say they don't want or need more - hey, then by all means go about your business and don't bother those who do. Aside from simply making others aware that more is possible if they so desire it, the two 'approaches' need not conflict or bother each other at all.

What has not been adequately addressed are the acoustical room models. The templates used as guides for 'tuning' the room. These serve as blueprints for the response. And in one sense, they can be very complex if one is going to understand all of the psycho-acoustical and acoustical underpinnings of the concept; yet they can be quite simple IF you are using the ETC to match the responses to the template. But lest anyone misunderstand - it is 'easy' partly if one understands or has experience as to how to effect response changes such that the ETC response actually achieves the changes necessary - which almost begs the original question!

To relate...I can pretty much look at the TC and tell you what needs to be done and to suggest specific treatments without seeing the room. Now, there will probably be few variations in that the particular reflection indicated might be switched between say, ceiling and floor and side walls - depending upon the orientation of the room (realizing few have any idea of that to which I refer - if the room is very wide, the floor ceiling reflections may appear first, while if the room is very narrow, the side wall reflections may appear first...)

I can do this as I have a template - a particular room response to which I am using as a goal.

Many here do not. And that is a problem in several ways. If one is not prepared to complete the project and to do what is required, you can fix a few anomalies that affect imaging and intelligibility, etc., but you will not have the fully tuned room that you might desire. But that might be enough.

I personally prefer the LEDE/RFZ concept as developed by Don Davis, Chips Davis, Russ Berger, Bob Todrank, P. D'Antonio and so many others - as a few already know who have referenced the resources. And one will note that the specifics are NOT what many find in the MANY erroneous and nonsensical write-ups regarding the model on the web - and of which many here have categorically stated is a flawed and dead model that began and died some 35 years ago!!! But that to which I refer is a refined model that is VERY much current and WIDELY used and assumed by many of he top professionals, including the names mentioned. Additionally, there are variants and options for particular applications!

But the details of this extend far beyond the scope of a thread where the intent was simply to get folks to understand the where and hows of the base ETC tool. And an understanding of the ETC tool is a pre-requisite to looking at this, as that is the 'language' that will be used.

Additionally, to fully treat the room in the manner many demand, may require quite a bit of time and effort, as is illustrated in your fine efforts with respect to diffusion. And then it will require a bit more followup to define additional factors such as an optimal and well defined ISD gap, and this MAY (read PROBABLY - in a very small space) include the use a technique called a Haas kicker, as you cannot go to a catalog and simply order one! And then there will be the necessity to employ techniques to increase the density of the later arriving diffuse sound field.

So, without wandering too far afield, it is important to note that one cannot simply "tell someone how to treat their room", as it requires a base understanding of the goal, the trade-offs and their effects, and what is involved before one simply thinks that tuning their room involves just moving an absorptive panel from one spot to another.

But that being said, the tool can be used quite effectively to address specific anomalies that DO impact the practical and real response to a positive end in almost any space by addressing basic fundamental issues - perhaps most common being he effects of early reflections from the speaker mounting, and work surfaces as so many seem to want to place their monitors directly on the desk. (With a bit of luck and arm twisting, maybe we can change this to encourage a more beneficial arrangement.)

But the larger point is, that each room will have its own idiosyncrasies based upon the gear and the arrangement of it in the room. Thus the point of learning HOW to use the ETC to identify the specific sources of issues in each room.

Standard general rules are great, but they do not resolve the specifics of your room. So it will require a bit of detective work to identify the real issues in YOUR room. So one cannot get hung up with the necessary dichotomy between general guidelines and the specifics of their room.

And another topic which will quickly become an issue - which I have tried to avoid here as long as possible, is the use of massive porous bass traps. There is a very real possibility that you will quickly reach point of conflicting purposes with very real conflicts. By this I mean, that in the desire to address modal issues, it is very easy to absorb the critical and easily absorbed energy above the critical frequency - where modes are no longer and issue and where we deal with specular reflections.

This is a PROBLEM with massive porous absorbers. In the process of dealing with one problem, they create another which many have been content to simply ignore.

There are some workarounds - of various complexity. And thus far the majority of those posting here been quite adamant in their frustration with having others provide a SPECIFIC solution to their inability to determine practical alternatives to THEIR specific situation. This mindset must change.

As is noted in many respected sources, this issue is almost a non-starter in many environments. But it will result in some becoming very upset here - for a fascinating array of reasons.

So, to wrap this up, what will be required is a more holistic approach to the system. If one is going to be preoccupied with simply one aspect then they need to be aware of this up front and avoid the issue, as the resulting debates as to whether one should eat or breath is probably not a fruitful one. Both are possible and beneficial. But they may require bit of an adjustment in comfortable preconceptions in order to accommodate a more balanced treatment of the room response.

----------------------------------------

(Addendum. Another prerequisite topic of several that needs to be addressed at some point that is often ignored or treated as a separate unrelated subject are the monitors!!!! Little regard is taken for their Q/dispersion pattern - which is a MAJOR cause of room problems. While i will not address it fully here, the speakers response cannot be made independent of the environment in which it will be used without potentially disastrous consequences!

Already we have many threads simply addressing SBIR issue with speakers designed for anechoic free field response that are utterly inappropriate for surface and surface wall mounting! And this does not even begin to address the dispersive qualities of the speakers and how they directly impact the reflections in a small space! And much of this is the fault of speaker manufacturers who are clueless - or more often - lazy who are too busy pushing meaningless free field anechoic frequency response curves than they are in designing speakers for tailored application environments! but the other responsibility is for end users to become more cognizant of the REAL actors and of their own intended environment and make better choices, rather than simply buying so 'hot' band name and then complaining that they work poorly in their room where the problem is in effect one of their own making due to the poor choice of tools... The moral: It is easier to avoid problems from inception through good choices than it is to remediate them reactively.)

[DanDan]

Lupo, regarding conduct and conflict. May I suggest you do some searches. You will find clusters of conflict consistently surround SAC/foxfyr posts. You will also find that any of the other contributors here do not suffer from that problem. Similarly none of us seems to have had a need for hiding our identity or changing it periodically.
There are indeed errors of fact also, sometimes covered by sleight of hand, changing goalposts, or revisionist editing of posts.
We should probably leave this thread fizzle out. Your own positive contributions regarding use of ETC are I firmly believe well noted by many.
DD

[SAC]

I can definitely understand the frustration of someone who has continuously denied the usefulness or validity of a tool that they consider useless in "small rooms" while repeatedly demonstrating that interpreting a gain versus arrival time graph is beyond their ability to interpret.

Thus far, there has been no attempt to present an acoustic model by which to tailor the response. There has only been the very general mention of some very basic attributes and techniques, such as an ISD and Haas 'kicker', that can play a constituent role in various models. And the Haas kicker was mentioned simply to dispute an erroneous claim that later arriving reflections cannot be used effectively.

Despite a couple whose sole purpose has been to attempt to dispute and discredit a technique and an idea that has been well established for quite some time, when the names of some of the principles who are directly responsible for the preponderance of the research and development of the methodologies - which should be sufficient to lend credence to the ideas - we listen to cries of 'name dropping' (so much for citing sources) instead of the acknowledgment that perhaps the ideas do have merit and that it might make sense to be open to becoming more familiar with them. But unfortunately, we have been treated to a few who simply continue to berate the ideas as they are simply beyond there apparent ability to understand them.

Who would have thought that such a simple tool as the ETC response would have generated so much ire and confusion - except with one or two whose sole goals are to either discredit that which they fail to understand, or to attack it on the basis that it does not do that which it was never intended to do.

The irony is that the basis for the measurement, as well as the larger models for which it is most useful, are valid and are well documented, as a few here who have inquired can testify. And there are additional source documents available from AES.

But I suspect that such a very simple and valid statement is sure to again raise the ire of a few who cannot stand another point of view that directly challenges their preconceived Flatland notions. And as with many endeavors, new ideas can be very threatening to some.

So, here's a radical idea. As a few are so vehemently convinced that this approach is so weak and unfounded, why don't they simply avoid it? After all, why should they continually denounce the approach only to have to watch as their observations regarding the worthlessness of the ETC and its larger uses are shown to be unfounded. There most be another thread where they can spread their gospel of hand clapping and the massive use of absorption to eliminate all reflections will be better appreciated.

As if we pursue this further, one of the first observations in evaluating many real rooms in attempting to determine the room's natural initial signal delay gap (ISD) is that many of the rooms we will look at are radically over-damped. Its not that the room lacks a natural ISD that we will seek to modify, but rather that the overuse of broadband absorption has detrimentally impacted far more than was intended. What was intended to address low frequency modal behavior has the undesirable potential to inadvertently impact far more than the low frequencies that are of concern in that application. Thus what is often touted as a solution, and which can have beneficial effects if judiciously applied, can also have serious detrimental effects on other regions of the rooms' response.

So, as with many old ideas, remediateing room issues will in many cases require modifying what was presented as a far too general solution.

This in and of itself should not be a big deal.

But we will no doubt have a few who will persist in their efforts to stop any discussion of ideas that challenge their pre-conceived notions.

So, I guess one might ask if the concept of the ETC response - if a basic gain versus arrival time plot - is understood. And does anyone still not understand how to determine the arrival time and the corresponding distance of travel that corresponds to the time of travel from the measurement. Note, I am not asking if one knows how to configure whichever software tool they chose to employ, but if what information the measurement provides is relatively clear?

If we can reach that point, we can then begin to discuss a room model and the behaviors that contribute to such a model a bit at a time. And from there we can identify some common issues that will be encountered in many already treated rooms, and also in the untreated spaces. And from there, we can discuss the general structure and each can explore ways to approach their particular situation, as there will be quite a variety of individual circumstances - and an understanding of the model, along with some thought as to how to solve the issues while not inadvertently introducing new problems can be explored. And the ETC can assist in determining the effectivenes of the treatment as well as to insure that addition harm is not inadvertently done in the process.

But it will be necessary to address some basic concepts, and then to evaluate specific rooms in light of that. It will make no sense to immediately jump into an existing room and to simply provide "the answer" without folks understanding what the concerns and options are first.

Thus, in another thread, I wonder if we can begin to explore the concept of at least one room model. And from that, to then begin to take a look at some virgin spaces and also some already treated rooms to see what might be encountered and how they might be evaluated and a treatment plan developed in light of the various concepts.

And for those who simply find the entire topic so abhorrent, instead of simply complaining, how about using the 'ignore function' to simply avoid the discussion of that which the sole or primary purpose is not intended to solve modal issues.

And with luck we can begin to look at some factors that many have not been aware of before, either because they were not familiar with the tools, or because while they may have heard reference to the possibility, have not been intimate with some of the methods and techniques that can be used to address the 'other' part of a room's response.

[SAC]

Wow. I really like the ignore function. I just wish it blocked them in all instances, not simply in subsequent viewings.

And I find the blank entry more constructive than his simple nonsense.

If you are so disinterested in doing more than clapping and playing with absorption and creating a near anechoic response, enjoy. And leave the rest of those who desire a bit more than your Luddite existence alone. After all, not everyone aspires to an acoustically ascetic life on par with the expectations of the Unibomber living alone in a small cabin without electricity. And not everyone needs you deciding for them that they have no bus9iness expanding their exposure, understanding, or activities if they so choose.

This is for those who want to go further, or who wonder why the imaging and locational cues are so goofy, as an anechoic or 'near' anechoic response allows for all sorts of misleading and inaccurate imaging ques, or for those who wish for a larger sense of space to their small room than what is physically present.

You have made your point that you can neither understand nor tolerate anyone disagreeing with your limited preferences as you assume that ALL either do not want more or that they are simply too simple to pursue more. Just as I am quite sure that there are some who will find your limited aspirations amusing and satisfactory.

But this is for those who either wonder what else is out there, or actually are curious to pursue additional options.

And as far as software packages, I have NEVER said that my purpose is to support platforms I do not personally use. The packages have dedicated support forums for that purpose! I know, I know...the world is just SO complicated... But if they want to use the available platforms, while perhaps not perfect in some of the supported measurement forms, we can make do the best we can. The concepts are still the same.

And while the topic of platforms has been raised, if you are brave, you might consider looking at ARTA. It is a very powerful dual channel FFT platform that costs FAR less than the level of performance justifies (about $125 USD for a single non-commercial user). And you can download it and use it for free - with the limitation being that you cannot save results. But it will definitely generate results! (One option might consider using SnagIt for screen captures, but a lifetime license for ARTA is the best buy in the acoustical measurement market if the freeware packages are not sufficient. So you have an opportunity to jump in and use it for free and to become used to it and the learning curve before you buy it.) And while ARTA's capabilities may take a bit longer to master due to its many extra options, its manual is extensive and exceptional. And in reviewing the manual, you will learn MUCH about the various measurements, techniques, and how they can be used. A fine piece of technical writing that will provide for much greater understanding than just how to operate the software! (Note, it also includes Steps and Limp - 2 programs for performing STEP analysis and also for performing impedance measurements as well as determining Thiele-Small parameters for those of you who might be interested in speaker design.)

In fact, I suspect that even IF one wants to pursue the measurement and analysis path a bit, than ARTA may be more than anyone will ever need as it is simply that complete! So, it is tossed out there for those who have an adventurous spirit.

ARTA can be found here: http://www.fesb.hr/~mateljan/arta/index.htm

[johndykstra]

Originally Posted by SAC

Thus, in another thread, I wonder if we can begin to explore the concept of at least one room model. And from that, to then begin to take a look at some virgin spaces and also some already treated rooms to see what might be encountered and how they might be evaluated and a treatment plan developed in light of the various concepts.

I'm game:

Very small control room remodel... less absorption ETC

[DanDan]

Worth repeating.

11th July 2009, 07:03 PM
foxfyr
This message has been deleted by jayfrigo. Reason: repeated insults, bickering, and unnecessary escalation.

DD