Acoustic treatment for my living room - Page 18

This is common knowledge in places where people exchange information about audio production.

Generally speaking mastering is done using a very good-sounding audio system that the mastering engineer is very familiar with, and then the results are checked on a number of r lesser systems to see how it translates on boom boxes, cheap earphones/earbuds, car stereos and the like.

After a while one gets a sense of how something will translate from the wide-range system to the other listening environments, and some of this cross-checking may be taken less seriously.

Even in the 1960s, most studios and mastering operations installed speakers called "Auratones" which were basically a cheap 5" driver in a small box, to provide an impression of how the recording would sound on a typical home radio.

Another example - in the 1960s and 1970s well-known record producers like Motown had steep slope high pass filters ca. 80 Hz built into their recording consoles so that all production was done with a sense of how things would sound on customer audio systems with no bass extension.

And so I dispute this statement. I dispute this statement because:

1)The reference is undefined - it may not be "how the music sounded in the mixing studio"
2)The reference is a moving target - one mixed studio will not sound like another, and there is only a very small subset of things you can do that brings you "closer" to the entire set of them
3)The reference is too often just plain garbage

All excellent points.

For example, is the goal to bring the orchestra into the listening room or transform the listening room into the concert hall?

Until that question is answered, defining a reference is impossible.

I didn't say it's a simple task. But it is simpler when judging the fidelity level of disc or file player, DACs, amplifiers and cables. You can look at their frequency response and analyze their transparency as a starter.

If you mean the reference source has poor quality, then you can just not buy it. By the way, if that's what you meant, how did you become aware of the quality of the reference?

Its not just "not simple" - it's undefined! Accuracy is well defined for all N-1 points in the signal chain (where the signal is still electric and/or digital). Accuracy for the last point in the signal chain (as soon as its turned into actual sound), is undefined.


I don't know about you, but I listen to the music that I like, not just the music that is well recorded.


Case in point, that last link I posted for you - if the artist in question has wrecked their hearing a long time ago, I am certainly not interested in "Accuracy" from their point of view

Undefined..., which means there's no way to tell what is or isn't reference sound. So, you tried to find it but you were unsuccessful therefore you've concluded that "it's undefined!"? Just curious, how long did it take you to search that out, hours, days, weeks or more?


I'm not sure who or what you are replying to. If it sounds like garbage, all I'm saying is don't buy it (there are sample features available online).


Specifically to your point #3, how do you come up with such conclusion about reference sound when you state it to be undefined? Are you sure you listened to the right material when you made that evaluation?

Thats not what undefined means.


I was replying to you - that's why I quoted you. I have lots of music that is on awful recordings that I wouldn't trade for anything. I sure wish the recording was better, but if wishes were horses....


To be more clear - The recording can be garbage, regardless of whether or not its faithful to the artists intent. This is not really a room acoustics issue though so perhaps it is not relevant to this discussion.

But what I'm wondering was, how did you become aware of this and how long did it take? Personal involvement with recording and mastering, observation and sampling of them, research on those subjects or something else?


I thought you were talking about the quality of reference, not the album listened through your system/s.


Now you want to switch the subject from "reference" to "recording"?

Maybe he used common sense. Or read this from Dr. Toole:


Would you mind answering your own question now and expand why your conclusion is different than Dr. Toole's?

Maybe? You can ask him directly. He seems to be on your side so maybe he will give you a straight answer.


Yes, I would because I don't want to cut in. I'll wait for my turn after you (you danced around but didn't answer) :

He gave the answer five different ways. Arny said the same thing and he is usually not on my side . But that wasn't enough so I chimed in with Dr. Toole's quote to see if that does it. Did it?


You never stop being yourself....

Ok Amir

I apologise. You WERE correct, I was completely wrong.

Seriously, I did think *we* were all on the same page, I did think 'fix the bass' was a given, that any of this other stuff (minor in comparison) only made sense if the basics were done fully.

Oh well, live and learn (and if need be) eat a huge serving of humble pie. And humble pie does not have to stick in your throat! If you have gained insight then HP could make the perfect desert

Bump...I showed you mine, will you show me yours?

Our low frequency measurements and computer simulations are in the article: http://www.madronadigital.com/Librar...imization.html. Go down to the EQ section.

If you are talking about my personal system, yes, I will definitely document it all. Indeed, I am looking it at that project as a working lab and key data for future articles and posts. I will likely be posting the journey on WBF Forum though.

Right now, I have barely got audio through the system. When your vacation house is 40 minutes from the nearest city with a balanced cable and you only go there on weekends and half the time you forget one other cable you need, it takes a while just to get the basics working . It is already a lot of fun. Amazing what you can do when you have such fine grain control over the sound of your room across all the channels!

So it will be a few weeks until I get it all sorted, speakers mounted, etc.

No worried Terry. You are a gentleman as always .

"make things up as you go", your dance move #4, amirm.
Look again amirm, he made one post since I asked him those questions. Can you quote those five different ways of his answer?


"redirect", your dance move #2.

Amir is right - I think I've explained my position pretty clearly. At this point I would be interested to know your opinion. What do you think a room should sound like that is as close to "reference" as possible? And what design elements are required to get there?

Not everybody needs to be just a consumer. Today, it is easier to jump from being a disconnected consumer to a producer of recordings than ever before.

Make your own recordings. You can buy great mics and a sonically accurate recorder for less money than a high end amplifier, speaker, or music player. There are usually groups in your neighborhood that are playing music that you can record.


You don't have to listen from a distance.
You can be there when the recording is made.
You can be in the same venue where the recording was made.
You can put your ears where the microphones were located to capture the sound.

+1. home recording has really spurred innovation with software and new products that then fuel the fire (for home recording) even further!!

the funny part is, amirm (attempting to speak on authority as usual), had this to say on tracking vocals a few pages back:


what he doesn't realize (probably due to his lack of experience tracking vocals), is that an easy and cost efficient way to record vocals is with a completely damped (dead) vocal booth! of which there are no high-gain destructive reflections that superpose with the direct signal at the mic to cause comb-filtering interference pattern within the frequency response (and this is ignoring having multiple high-gain copies of the signal being recoded within the haas interval for intelligibility purposes!). and what did toole have to say about comb-filtering within the recording?

That is a truism. But just because you can buy and turn on a table saw, it doesn't mean you can make beautiful furniture. Or would want to. Even if I could get Adele to come to my house for me to record her for free, I wouldn't want to jump in and pretend I have such expertise just because I can buy a capture card, mic and a program to record tracks.

But sure, if you can satisfy your enjoyment by purely recording material yourself and with the right quality, go right ahead. For the rest of us, we absolutely are customers of both the hardware and software. And we like the best harmony for the two.

Again, it appears that reading and comprehending remains a lost art around here with some.

I said nothing about making world-class recordings. What I promised is and I quote:


Those are all benefits that anybody who puts forth the time and effort is practically guaranteed to receive. Prove me wrong. ;-)

Anybody who has spent even a few minutes in a good studio or just glanced at a photograph of one notices the movable absorbers, gobos and isolation booths that are part and parcel of a professional recording operation.

Just for grins here is a picture of a typical practice booth of a kind that is widely used by instrumental and vocal musicians: What is that I see on the walls? ;-)

but! but! but! singers aren't supposed to like singing in the absence of reflections!!

i called his statement out a few pages back after he made it as well but did not get a response. "How many singers do you know that like to sing outside where there are almost no reflections? Have you tried to sing yourself there? " --- it must be an absolute painstaking experience for those at baseball games singing the national anthem when the nearest boundary is 200ft away and the ground (grass) is absorptive

Did you comprehend the point Dr. Toole was making related to the topic at hand -- sound reproduction in our room?


I prove that your point is off-topic . If we are arguing about which airline is better, you chiming in and saying you can buy your own airplane on the cheap and go where you want is off-topic.

So let's put them in an anechoic chamber then. That is the ultimate expression of a reflection free room. Would you explain how this room is a version of that?



This is what an anechoic chamber looks like:



They look nothing like each other now, do they?

Maybe you tell me that they use ruler flat measurement mics for vocals. Maybe you tell me that the music I hear at home was recorded from that room with zero processing. Maybe you are telling me that if I stood in that room I would hear exactly what is delivered to me on the CD. Is this what you are saying?

Or is the point that they like to record the sound dry and then manually add the processing they desire down the chain? And that even that dry choice, is not devoid of reflections? Because that would the clear explanation, not an implication that people like reflection free versions of their voice because there is a room with 1 inch foam on its walls.

That is not a fair answer to him Local. He asked you to define the term and you ask him if he already knows what it means? He is asking a good question relative to how many times you use that phrase. That you need to define and clarify your position there. I will go ahead and do that for him.

Since you are using that as a definitional term, I thought I go and see who has used in the literature. I searched for "speaker-listener response" with our without dash and got no hits on Audio Engineering Society library or that of Acoustic Society of America. I had to use quotes as otherwise the words in that term are quite common otherwise. So if this is an industry term, it is a very rare one and as such, folks should not be expected to know what it means automatically.

So to get to the bottom of it anyway, I did a general search on the Internet. Interestingly enough, I only got a handful of the responses. The first two were your post on the pro recording forum, Gearslutz. And one of the other a link to this discussion thread! The other three links appear to be related to linguistic or some such thing and unrelated to this topic.

But we have what we need in you expanding the term on Gearslutz. Here is the key quote with this term in it:

"without traversing down the rabbit hole of psycho-acoustics, there are two basic concepts: the first is a completely damped room with respect to speaker-listener response. the direct signal is all that is heard and no room reflections are introduced to the listening position. the speaker-listener response is anechoic. this is referred to a Non Environment Room (NER). the ETC would show the direct signal spike, and then directly followed by the ambient noise floor. "

Now we get some place because Non-environmental is an industry term. Let's see who it is defined there. From AES Paper, Objective Evaluation of a Non-Environment Control Room for 5.1 Surround Listening, by Degara-Quintela, Norberto; Pena, Antonio; Torres-Guijarro, Soledad (2008):

"The non-environment design of control rooms [1,2] was proposed around 1982 by Tom Hidley, where the goal was having an acoustical environment with the minimum of room sound. Sound radiates from the monitor loudspeakers with barely any sonic influence from the room. This basic principle allows a reflective floor and a diffuse reflecting front wall where the loudspeakers are flush mounted. Huge absorbers cover the side walls, rear wall and ceiling, creating an almost hemi-anechoic space for the monitoring while keeping comfortable working conditions thanks to the reflecting front wall. This design is supposed to preserve the sound characteristics of the mixing and production studios when taking the product to other listening environments, a fact that seems more and more important nowadays."

Before digging in, let's review what two goals the recording engineers are generally attempting to meet:

1. They like to hear just the direct sound of the speaker and no reflections. They consider this "accurate" which is the term Local keeps using. Taken to its ideal place, this means an anechoic chamber -- a reflection free space that adds nothing whatsoever to the sound of the speaker.

2. That an anechoic chamber is not a pleasant place to mix music or enjoy it.

For anyone doubting #2, here is F. Alton Everest in his book, Master Handbook of Acoustics:

"The delicate and sensitive nature of our hearing can be underscored dramatically by a little experiment. A bulky door of an anechoic chamber is slowly opened, revealing extremely thick walls, and three-foot wedges of glass fiber, points inward, lining all walls, ceiling, and what could be called the floor, except that you walk on an open steel grillwork.

A chair is brought in, and you sit down. This experiment takes time, and as a result of prior briefing, you lean back, patiently counting the glass fiber wedges to pass the time. It is very eerie in here. The sea of sound and noises of life and activity in which we are normally immersed and of which we are ordinarily scarcely conscious is now conspicuous by its absence.

The silence presses down on you in the tomblike silence, 10 minutes, then a half hour pass. New sounds are discovered, sounds that come from within your own body. First, the loud pounding of your heart, still recovering from the novelty of the situation. An hour goes by. The blood coursing through the vessels becomes audible. At last, if your ears are keen, your patience is rewarded by a strange hissing sound between the ker-bumps of the heart and the slushing of blood. What is it? It is the sound of air particles pounding against your eardrums. The eardrum motion resulting from this hissing sound is unbelievably smallonly 1⁄100 of a millionth of a centimeteror 1⁄10 the diameter of a hydrogen molecule!

The man can write, can't he? Given that, we see that the position the pros put themselves in is untenable. You can't have just the sound of the speaker and not have the discomfort that goes with it. So what is their solution? Let's make some of the surfaces reflective. Which one, leads us to the flavor of the day with a catchy term to go with it. In this case, non-environmental room. Localhost calls this room to have "anechoic speaker-listener response.

Let's start at the top: there is only one definition of anechoic and it says reflection free. That is what the term means. An NE room per definition above has its floor reflective. So clearly right there, we have floor bounce and nothing like an anechoic chamber. In another thread, Localhost post this graph to back his position of accuracy:



Clearly the graph articulates that floor bounce is bad. And that the definition of accuracy is zero reflections per the second configuration below. A transient is sent to the speaker (the spike) and zero reflections come back. Clearly we don't have that remotely being the case in an NE Room. Indeed we have the representation on top of the graph with floor reflections.

That being teh case, the terminology as used is not accurate. It is like saying the drink is sugar-free, only to find sugar as one of the ingredients, albeit much reduced. Yes, the motivation is clear. If you scare people about sugar, you don't want to look like you are still using it.

As a side note, who says floor reflections are a good thing in that NE Room model? Why that? What extensive research led to that choice being optimal? Dr. Toole's research says we like lateral reflections but those from other directions are not beneficial. If NE Room is where it is at as the prime example of the phrase Local is using, where are the listening tests that show that to be a superior method? If it is not a superior method, why keep using the phrase?

This is the reason you don't want to chase things done in the Pro world. A room model conceived in 1982 by Hidley prior to so much research past that into what reflections mean to us as listeners, should not be the formula put forward for people who want to enjoy music. For someone recording it, and wanting to hear what a knob adjustment is doing, that is fine and is their choice. But for a recommendation to stick for consumers, there needs to be more evidence of its goodness than, what don't you understand about this term?

No, he is not.


Think again. You claimed that reference is "undefined!". You even used exclamation point to make your claim strong. In the same reply, you claimed that "3)The reference is too often just plain garbage ". I asked you how you can post an evaluation about something that's undefined but you never answered or what you consider as "explained" doesn't address the question. In other words, you just danced around the question.

For simplicity sake, lets say your dancing answered the question about the sound quality of reference, then why haven't you retracted your claim about reference being "undefined!"?

I'm merely pointing out that you are contradicting yourself. Which is it, is reference undefined or it is defined but it is too often just plain garbage? Can you stick to one?


deflect, redirect... 1, 2 amirm dance moves.
Once you bring resolution to your claims and amirm does to his, I can get to those.

To deal with vocal frequency range, shallower absorbers can do the job so it doesn't have to be recorded in an anechoic chamber looks like that. I thought you would know this already.

Vocal range can be <100Hz!

As for the rest, several other people very clearly understood what I was saying. It's not my fault you are unable to.

have you ever tracked vocals? a simple yes or no will do.

"So let's put them in an anechoic chamber then. That is the ultimate expression of a reflection free room."

no, we don't need to put them in an anechoic chamber. why do you insist we should? what exactly do you have contention with with regards to dead (cheap and easily constructed) vocal booths that have been used successfully for decades? a full blown anechoic chamber is not required here - especially as we aren't looking to squeeze 30-40 people in there but merely have design requirements for 1. why do you feel you need to go to such extremes in order to deflect from the completely erroneous comments you made regarding singers? just who are these singers that you state do not like singing outdoors?

hmm, you haven't done much of this in the real world have you?

so, let's go back to my statement:


hmm, again, your complete lack of knowledge of the "different types of reflections" shows your ignorance on the topic. low-gain (effectively anechoic) reflections are not necessarily destructive. the high-gain reflections that cause the constructive/destructive interference pattern known as comb-filtering in the frequency response is of concern when recording -- of which toole states the following:


and this was in response to YOUR commentary that singers apparently (since you appear to speak for all singers in existence) do not like to "sing outside in the absence of reflections). yet all professional recording studies utilize dead vocal booths, gobos, etc (eg, tools at their disposal) for tracking vocals.

hmm - and how much experience do you have recording vocals again? zero?

so we can take a look at how things are done and have been done in the real world for decades, or we can take amir's opinion of which he has zero experience in regards.

any more distractions or tangents from the fact that you still have NOT provided how to utilize the rt60 measurement to dictate where, how much, and what types of treatments in a reproduction space?

no?