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Why not "DEAD" room fro mixing and mastering?? Studio Monitors
Old 16th February 2011
  #31
Gear Head
 

Very interesting discussion. The amount of info I've gathered from this site is nothing short of amazing. You guys know your stuff man!

I've thought about this for years and still go back and forth.
Once thing for sure is an acoustically "dead" environment does create an auditory sense of no space when meandering about the room.

I've never been in an anechoic chamber, but I've been in "dead" rooms, so I have an idea, but without the direct comparison, it's hard to know for sure.

One thing we all know about is the subjective and persuasive nature audio can present to the listener. If you're set against "dead" rooms, this mindset could lead to negative thoughts for some. I realize we all need to be "open" minded and try to throw away everything and just listen.
Having said that, I agree that there is something unnatural about listening to a mix in a dead room. As mentioned here, we're not used to hearing music this way.

We all know that small control rooms are a problem for early refections and bass modal issues. We have to implement traps to control the bass, but at the expense of possibly making the room too "dead".

I'm currently in a small control room and trying to make this work right now. I'm considering installing slats in some (most) of the 4x2 (4" ROXUL ROCKBOARD 60) hanging broadband absorbers that are located behind the mix position. I'll keep the first reflection traps absorbent (no slats). The area behind the mix position and speakers are insulated well with bass traps in the corners. The room is small. I do not have the exact numbers. but it's around 10x12x8. There are three super chunks in the corners, but there's a door in one corner, so I'm a bit screwed there. I'm working trying to minimize bass issues in the back of the room. I plan on doing something with the door issue. The ceiling has 4x2 traps hanging in a unique stucture with LED lighting and covers about 24 SQft and starts
over the mix position. I plan on building unique bass traps for the side ceiling meets wall.

Currently, the room is on the "dead" side for reflections. I'll have to test the room and post the data here, I'm hoping installing slats can come close to evening out the decay time for mid to high. Well, I won't know until I do another current room test.

I built my 4x2 traps with front trim covering the staples holding down the burlap. It sucks I have to take these apart, but it will be worth it if the slats can help diffuse the high end and bring some sense of reality back.... Having said that (LOL), what is reality. There's probably around 1/2" height left between the front cover and insulation, so I'm hoping the slats will fit OK. I can re-staple the cloth and re-install the trim after I install the slats in the traps. Any ideas on the best slat layout plans for these traps?

I'm still not 100% confident that a room with even absorption is a bad thing. Yes, I do realize it's about the overall decay times.
But, some basic thoughts sure makes one think they would have a better idea of early reflection information and space in their recordings if their listening environment was not adding to and smearing this information...... damn it, I'm still going back and forth on this.

I'm sure there's an ideal fine line between both. What should I expect for a reasonable RT60 (or RT15) in a room this size to maintain a good quality mix condition? Well, I just read DD's response to this and he suggested the max may be around 300ms in the low end. 50-100ms at 4K. I realize this data is dependent on room size. Are there ideal numbers in certain ranges to stay within for a mix room? I realize all decay times the same may be the best, but it's probably not easy to obtain in reality.
Old 16th February 2011
  #32
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Quote:
Originally Posted by vx2000 View Post
but it will be worth it if the slats can help diffuse the high end and bring some sense of reality back.... Having said that (LOL), what is reality.
the slats will only be seen by wavelengths less than the slat, right?
so installing 1" wooden slates on your traps won't have much of an effect on wavelengths less than 1".
Old 16th February 2011
  #33
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What if the gaps are also that size...then it's like...
Old 16th February 2011
  #34
Gear Guru
Lite

I reckon slats do not do a huge amount, but for that very reason are very safe. e.g. the 543 sequence from Newell achieves 50% cover. This is way ahead of the 30% or so required for full absorption, but it does replace half of the absorbent surface area with reflective material. All good IMHO.
If you want to get more serious about livening things up, you have to look to sophisticated and expensive diffusion. Personally, unless the room is big enough to 'deserve' really extensive treatment, I recommend the money go elsewhere. e.g. Serious bass traps, serious headphones and amp to drive them.

DD
Old 16th February 2011
  #35
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avare's Avatar
 

Quote:
Originally Posted by vx2000
I'm currently in a small control room and trying to make this work right now...
Why not start your own thread instead of hijacking this one?
Old 16th February 2011
  #36
Gear Head
 

Sorry avare,
I did not mean to hijack the thread.
I was on topic with "dead" room, but I might of gone to far in mentioning my situation with a "dead" room and adding life with a diffusion question.
Old 16th February 2011
  #37
Hi,

I always thought that the main reason for control rooms not being dead is that the consumer rooms aren't to begin with.

With loudspeaker playback, the room reflections will always add to the loudspeaker signals. This means, you will have to set your microphones or mix differently than if you only listen to the speakers without addition of any room.

Dirk
Old 17th February 2011
  #38
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Hannes_F's Avatar
 

Haha, for one moment I read:

Quote:
Originally Posted by dtf View Post
I always thought that the main reason for control rooms not being dead is that the consumers aren't to begin with.
Old 17th February 2011
  #39
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Ha!

I'll have a dead room when I'm dead.
Old 17th February 2011
  #40
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Quote:
Originally Posted by dtf View Post
Hi,

I always thought that the main reason for control rooms not being dead is that the consumer rooms aren't to begin with.

Dirk
exactly. why would you want to mix in a space which is not at all representitive of the spaces where your product will be heard? If you are worried about the pod people, can't you just check mixes on cans?
Old 17th February 2011
  #41
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It's a psychoacoustics issue.

The Film Facts Blog: 'Old Man's Dick'

You obvious don't want to mix in a worst-case-scenario environment. The idea that you'll overdo reverb etc. if you're in an excessively dead room plays into the expected perception of the listener in his/her space. I personally prefer to assume that the listener cares as much about music as I do and act accordingly.
Old 17th February 2011
  #42
Quote:
Originally Posted by Brainchild View Post
You obvious don't want to mix in a worst-case-scenario environment. The idea that you'll overdo reverb etc. if you're in an excessively dead room plays into the expected perception of the listener in his/her space. I personally prefer to assume that the listener cares as much about music as I do and act accordingly.
Indeed, you obviously don't want that. However, it is clear that you do not want to imitate the problems of the final listener's environment, so you make sure that the reflections of your room are controlled. I didn't mean to imply that one should mix in a normal living room.

Dirk
Old 19th February 2011
  #43
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RKrizman's Avatar
 

This is an interesting subject and an issue I'm dealing with right now as I complete the new treatments in my room. When I had too much trapping up and the room was too dead it was first of all very uncomfortable for visitors. People reported, and I concurred, that they felt like their sinuses were stopped up. Moreover, the music tended to "lay dead" between the speakers. Yes, I could hear every detail, but nothing was triggering my emotional aesthetic, which IMO is really the source of all mix decision making. The mix isn't done until it moves the listener.

Over the years I've worked in some of the top control rooms in Los Angeles and London, rooms with amazingly facile acoustics, and never once did I ever experience any uncomfortable anechoic effect. So I think a balance of all the factors should be the goal.

The solution that is working for me is to eliminate with various absorbers all the first reflections from behind and beside the speakers. Then the back of my room uses diffusion to throw some life back into the mix position. All this, coupled with extensive bass trapping is getting me toward a balance that is both accurate and enjoyable.

I recommend consulting a designer to advise you on putting the right stuff in the right places.

Someone mentioned psychoacoustics. My room is still a little on the dry side, but the discomfort goes away when the sun sets. (Lots of natural light during the day). I think that when it's darker, your mind just accepts what it is hearing. During the day the brain experiences a disconnect between what it "sees" as a largish, spacious room but "hears" as more closed in and muted than the visual would suggest. I think this can be a source of some cognitive dissonance which one experiences as discomfort.

Good luck,

-R
Old 19th February 2011
  #44
Gear Guru
Psycho

Quote:
first reflections from behind and beside the speakers
Behind?

I wonder if we used words other than 'dead' would perceptions change over time. How about 'pure', 'echo free', 'Hi Fidelity'.
I must say that my own repeated experience has been that the removal of reflections around and above the speakers brings the imaging aspect from b/w to colour, even 3D.

I haven't listened to music in Anechoic, but I had no discomfort in there and suspect I would have no problem with it. I also use great headphones extensively. Finding a room colouration to remove or say choosing a reverb, become very clear and sure and even easy when there is no listening room interfering with the information.

DD
Old 19th February 2011
  #45
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RKrizman's Avatar
 

Quote:
Originally Posted by DanDan View Post
Behind?

I wonder if we used words other than 'dead' would perceptions change over time. How about 'pure', 'echo free', 'Hi Fidelity'.
I must say that my own repeated experience has been that the removal of reflections around and above the speakers brings the imaging aspect from b/w to colour, even 3D.

I haven't listened to music in Anechoic, but I had no discomfort in there and suspect I would have no problem with it. I also use great headphones extensively. Finding a room colouration to remove or say choosing a reverb, become very clear and sure and even easy when there is no listening room interfering with the information.

DD
Yes, behind. Around. Anywhere there could be a first reflection to the listening position from the front of the listening position. The diffuse sound returning from the back wall, however, is late enough that it doesn't comb filter like the shorter reflections and instead enlivens the stereo image.

I don't think it's a matter of semantics. You put too much absorbant in a room and cut down the reflections to zero and, to me, it becomes a very uncomfortable environment, call it what you will.

I strongly feel that killing off all reflections should not be a room designer's goal.

-R
Old 20th February 2011
  #46
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SörenHjalmarsson's Avatar
 

Quote:
Originally Posted by Hannes_F View Post
Haha, for one moment I read:
LOL!

Quote:
Originally Posted by RKrizman View Post
I strongly feel that killing off all reflections should not be a room designer's goal.
Nor do i think it is.

There seems to be some confusion during this thread regarding what the goal is in a critical listening environment (for production) as opposed to a listening environment that is ment for reproduction. There also seems to be some confusion regarding what a 'dead' environment is as opposed to an anechoic response.

For a critical listening environment what we want is accuracy. As soon as we start changing things around and introduce random reflections in order to make the listening experience perceived as 'better', we exchange that accuracy in favor of a subjective improvement - here of course, i am not talking about a properly defined spatial response, achieved according to standards - Just like with speakers, the goal for Hifi and reproduction is a pleasent listening experience, whereas in a studio or in production the goal is to hear the source material as it really is, without alterations i.e. accurately.

Properly designed anechoic spaces (like the NE based rooms) minimise the influence the room has upon the sound, offers an accurate listening and enables the engineer to analyze the source material with precision.

A dead room however, generally speaking, is NOT very pleasent to work in for long hours (sorry DD heh) and therefore, even the anechoic rooms, should be skillfully designed so as to preserve reflections that enables creature comfort, but without those reflections being given the opportunity to imped upon the accuracy, or influence the listening experience.

Another advantage that the NE approach claims, is the small amount of difference in the response between different rooms - these kind of standardisations have been hard to achieve before because rooms of the more convetional designs will have different percieved characteristics if the sizes, shapes, materials of constructions and/or if the furniting/interior designs are not identical. This is also becoming more important, since today, files are changing hands and environments more frequently during a project than ever before.


Cheers,
Old 20th February 2011
  #47
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SörenHjalmarsson's Avatar
 

Quote:
Originally Posted by RKrizman View Post
Yes, behind. Around. Anywhere there could be a first reflection to the listening position from the front of the listening position.
Like DD i can't see how an early specular reflection could arrive from the front wall, could you explane further please?


Cheers,
Old 20th February 2011
  #48
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Nordenstam's Avatar
 

Just adding that properly implemented returns of energy can aid in accuracy.(multiple looks in psychoacoustics)
Old 20th February 2011
  #49
Gear Guru
Grateful

No worries Soren, I may be the only Grateful Dead fan here.....
Lupo, I think we would have to define accuracy first.
IMHO, great headphones seem like the best way to hear exactly what is in the recording. Coupled with 'real' stereo recording, they also seem to deliver the closest thing to what ears do hear at a real concert. That's my example two types of accuracy.
Other definitions or examples?
DD
Old 20th February 2011
  #50
SAC
Registered User
 

Building upon what others have mentioned...

One thing we would all benefit from would be for us all to use the same terminology to describe the same behavior.

First, it is such a common occurrence to listen to so many refer to reverb or reverberation and T60 measurements.

There is no appreciable reverberant soundfield in a small acoustical space. (And there is No directional component to a statistically reverberant soundfield). A reverberant soundfield adds to the noise floor.

Reverberation is not perceived as a decay or delay component as so many have come to think due to that @%#$& mislabeled "reverb" control that all of us grew up with that is so common on musical instrument amplifiers!

So... if there is no reverberant soundfield in a small acoustical space, what is it that accounts for the sense of 'liveness' - or the sense of a room being 'dead'? (So for all intents and purposes, we should banish the various forms of the term "reverberatiion" and RTxx calculations from our discussions with respect to small acoustical spaces!)

Its really pretty simple.

The perception of a room's 'liveness', or conversely its 'deadness', is the ratio of the direct signal gain with the first reflection gain levels.

The greater the first reflection gain level is relative to the gain of the direct signal, the more 'live' the room seems.

When you clap your hands in a room, that is what you hear that determines how 'live' or 'dead' the room sounds.

(One will also note that this is the same relationship that is defined by a properly implemented LEDE room between the direct signal and the termination of the ISD - which is essentially the first reflection and the room is perceived as a relatively 'live' room.. Conversely, as you effectively remove such a return in a Non-environment room, it is perceived, by comparison, as a 'dead' room.)

The problem with referring to the phenomena as reverberation is twofold. Not only is it the incorrect term for the behavior, but using the term brings with it a whole set of additional relationships that simply do not exist nor apply. And attempting to apply these associated concepts inappropriately in a space will simply result in additional errors if one acts upon such assumptions - and I think we can all agree that it would be nice to avoid that ...

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

As has been mentioned earlier, In small acoustical spaces you have modal resonance and decay (or 'persistence') at particular frequencies. And also, for those who fancy that they might have a large acoustical space - for a room where you are dealing with music as the source material with a response down to 30 Hz, you are looking at a minimum volume of ~251,000 ft^3!!! Having a hard time getting an idea of just how large this space is? Well, if your room has an 8 foot ceiling, that a room ~177 feet X ~177 feet! ...Still think yours might be a large acoustical space??? heh
Old 20th February 2011
  #51
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RKrizman's Avatar
 

Quote:
Originally Posted by SörenHjalmarsson View Post
Like DD i can't see how an early specular reflection could arrive from the front wall, could you explane further please?


Cheers,
I believe DD's reply was "behind?"

If you guys have a point to make, then make it.

-R
Old 20th February 2011
  #52
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behind the speakers = front wall. I don't see the confusion here. Though I also don't see the aversion to having absorption behind the monitors on the front wall either. SBIR reduction along with preventing secondary, third order, so on and so on specular reflections combining with direct sound. Were I not to plan for a soffit mount main, or following a detailed modeled response, I would certainly treat the front wall.

But I also doubt the effectiveness of a panel with the average 2x4' face size to have much effect on SBIR... regardless of thickness.
Old 20th February 2011
  #53
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RKrizman's Avatar
 

I understand that the frequencies that bounce off the wall behind the speaker, from the speaker, may be too low to contribute to any comb filtering at the listening position. However, in my own experience I've found it beneficial to deaden this space at least to some degree (still tweaking) to reduce "glare". Perhaps this is from reflections off the back wall re-reflecting off the front to the mixing position. If I misspoke about this I don't want it to drag the discussion off topic.

In another thread I posited whether or not it is advisable to deaden the space behind the speakers, and this discussion might better be pursed there. The point I was making, which i don't want to be distracted from, is that I don't believe a completely all around dead or absorbed or anechoic space should be the designer's goal. I'm surprised to find that this is controversial. In all of the discussions in this forum of what is the best way to treat a room it seems that maybe we all don't agree on what the end product should be.

-R
Old 20th February 2011
  #54
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RKrizman's Avatar
 

Quote:
Originally Posted by johndykstra View Post
behind the speakers = front wall. I don't see the confusion here.
There is no confusion. I understood what he meant by "behind?".

-R
Old 20th February 2011
  #55
Gear Guru
The Point

'Not too dead' and probably unnecessary front wall absorption seems self defeating and contradictory to me.

The speakers do not radiate HF behind broadly speaking. They simply don't.

Flutter from HF coming from the back wall seems unlikely since that is probably deeply broadband trapped. If it has diffusion, there won't be flutter.

Some of us have had repeated lack of result trying to treat SBIR with traps behind speakers.

So pretty much the only case I can see for trapping behind speakers is in a surround scenario, of if you cannot treat the back wall deeply enough.

Ethan has similar views RealTraps - Front Wall Absorption

Check out Newell and others NE designs. Fully reflective front walls, (normally with soffit mounting but not exclusively)

DD
Old 20th February 2011
  #56
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SörenHjalmarsson's Avatar
 

Quote:
Originally Posted by RKrizman View Post
I believe DD's reply was "behind?"
And so was mine. thumbsup Behind the speakers/front wall - tomato/tomato. heh

Quote:
If you guys have a point to make, then make it.
I was merely curious to hear were you're coming from R.

Quote:
Originally Posted by RKrizman View Post
The solution that is working for me is to eliminate with various absorbers all the first reflections from behind and beside the speakers.
Allow me to explane... When you say first reflections, it sounds to me like you need to treat primary reflections (first order reflections) at the front wall, just like you would sidewalls and ceiling etc... ...which you don't.

Quote:
Originally Posted by RKrizman View Post
I understand that the frequencies that bounce off the wall behind the speaker, from the speaker, may be too low to contribute to any comb filtering at the listening position.
Au contraire! The biggest reason for treating the front wall (if you are using free standing speakers) is to reduce SBIR - which leads to LF comb filtering... Broad bandwidth absorption is most effective on the front wall and in corner locations.

Quote:
The point I was making, which i don't want to be distracted from, is that I don't believe a completely all around dead or absorbed or anechoic space should be the designer's goal.
Depends on what you mean by 'dead'. Still dont know if you are referring to an anechoic response model (without a laterally arriving diffuse field) which some people will advocate and some will not i.e. this is a subjective thing - or if, by 'dead', you mean an overly dampened space in which it can become strange to dwell for longer periods of time - according to everybody apart from DD.

Quote:
I'm surprised to find that this is controversial. In all of the discussions in this forum of what is the best way to treat a room it seems that maybe we all don't agree on what the end product should be.
That we can agree on! Humans are subjective beeings, and that's the reason that there are different designs and response models in use.


Cheers,
Old 20th February 2011
  #57
Gear Guru
DD

And what does DD really stand for......

Soren have you had success with SBIR treatment? I haven't and Lupo has been pretty disappointed with his efforts also.
Rod has described good success, but the panel was close to the speaker, not the wall.

DD
Old 21st February 2011
  #58
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SörenHjalmarsson's Avatar
 

Thinking out load!!

DD,

Untreated boundary surfaces close to the speakers have the ability to reflect waves directly back to the source, which in turn, cause 'wave interferences'. I can't see why treating those surfaces with thick absorbtive materials, all around the speakers - sidewalls, ceiling, corners AND front wall - would NOT help to reduce that effect, so that when the reflected waves interact with the direct sound, the intensity of the reflected waves will have been reduced and the 'acoustic interference' minimized.



Cheers,
Old 21st February 2011
  #59
Gear Guru
Test

Of course Soren, but we speak from repeated tests which showed no worthwhile result. Check it out.
DD
Old 21st February 2011
  #60
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Jens Eklund's Avatar
https://www.gearslutz.com/board/6121622-post20.html

The dip at 145 Hz was primarily due to SBIR.
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