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New mastering room Virtual Instrument Plugins
Old 15th August 2007
  #1
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redroomstudio's Avatar
 

New mastering room

Hi

I´m thinking of moving my studio into a new facility. The new room that I´m looking at is larger then my current room. But being a novice with acoustical treatments of rooms I was hoping for some comments from the GS community. Bass traps are going to be built and some modifications are going to be done as I get to listen to the room "in action".
I am aware that you have to actually have to hear a room to see how it works, but if someone has any general input you are welcome to comment.
The room is 29.2 long, 16.08 wide and 8.73 from floor to ceiling (all numbers are in feet).

Can you see anything out of the sketch I´ve made that needs some extra attention? How would you treat this room?
New mastering room-redroom-ila-gs-2.jpg

Thanks!
Morten/Redroom
Old 15th August 2007
  #2
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Hi,

could you maybe show us where you're thinking yourself placing speakers/console etc. etc.

meters would be fine .. we're not all americans on GS ...
Old 15th August 2007
  #3
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Ok, should have posted in metric scale also, being a european myself

Depth : 8.9 meters
Width : 4.8 meters
Height: 2.66 meters

The placement of the workstation and speaker is not fully worked out yet. But I´m thinking of something that looks aprox like this:New mastering room-redroom-ila-gs-3.jpg
Old 15th August 2007
  #4
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The depth is more or less around the double length of the width of the room, perhaps this may cause some riniging modes. Here is a link where you can calculate the wavelenths, so you might get an idea which low-frequencies and their harmonics you'll have to treat. And here is another link which might be usefull as well.

Good luck...
Old 15th August 2007
  #5
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Hi Morton,

well small question .. difficult answer .... I would suggest reading until you drop the forum by John Sayers John Sayers Productions

there you will get a good idea on the possibilitys and the do's and dont's .....

don't kill you're room by using to much bass-trapping .. just do the basic's first and then get some accoustic spec. to hear/meassure you're room ... adapt from there ....

mayby you could apply some ceiling and wall constructions to avoid to much standing waves ....

accoustic treatment ( diffusors ) from vicoustic is much cheaper then RPG .. check their products ..... I just orded a sample of 8 diffusors ..

:. Welcome to*Vicoustic .:




enjoy .. and have fun .... how is the noise from the surroundings ...



Quote:
Originally Posted by redroomstudio View Post
Hi

But being a novice with acoustical treatments of rooms I was hoping for some comments from the GS community. Morten/Redroom
Old 16th August 2007
  #6
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Use the golden mean ratio equations to position properly your monitors and listening spot .

Ethan Winer, John Sayers and Wes lachot are the men to help you and maybe design the room for you.

They helped me a lot when I rebuild my contorl room. Sound is 60% better now.
Old 16th August 2007
  #7
Quote:
Originally Posted by Alécio Costa View Post
Use the golden mean ratio equations to position properly your monitors and listening spot .

Ethan Winer, John Sayers and Wes lachot are the men to help you and maybe design the room for you.

They helped me a lot when I rebuild my contorl room. Sound is 60% better now.

60% better???

How did you measure it?
Old 16th August 2007
  #8
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Quote:
Originally Posted by inlinenl View Post
Hi Morton,

well small question .. difficult answer .... I would suggest reading until you drop the forum by John Sayers John Sayers Productions

there you will get a good idea on the possibilitys and the do's and dont's .....

don't kill you're room by using to much bass-trapping .. just do the basic's first and then get some accoustic spec. to hear/meassure you're room ... adapt from there ....

mayby you could apply some ceiling and wall constructions to avoid to much standing waves ....

accoustic treatment ( diffusors ) from vicoustic is much cheaper then RPG .. check their products ..... I just orded a sample of 8 diffusors ..

:. Welcome to*Vicoustic .:




enjoy .. and have fun .... how is the noise from the surroundings ...

hi inlinenl,

would be interested how they look in real life. this pic looks like a
rendered computer image. how much are this 8 pack ?
If they are made of Polystyrol they might be very soft surface wise.
But should not affect the sound up to a certain frequency.
Please post the results when you installed them .

greetings

andreas
Old 16th August 2007
  #9
Quote:
Originally Posted by ak23 View Post
hi inlinenl,


If they are made of Polystyrol they might be very soft surface wise.
But should not affect the sound up to a certain frequency.

andreas
i totaly agree....
i works up high mediums not bellow

i built mine in real wood

Old 16th August 2007
  #10
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livingstone ... looks cool .... p.s I've done/been enough handyman .... weight is an issue !!!

AK23 prices are on the web ... but around € 170,00 for 8 times 60cm x 60 cm x 15cm

Morton, The website from Ethan Winer ( realtraps ) RealTraps - Home has loads on great info and you'll love the video's .... it's even fun ( spec. the one with doug and ethan hanging some basstraps ) ... but ethan has a perfect website with very accesable/readable info .. his RFZ is interesting .. but consider diffusion also in you're package ....
Old 16th August 2007
  #11
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Thank you for all the links, the more I read the less muddy the process becomes.

I agree with you inlinenl in regards to killing the room with too much treatment. I´ll set up the basic room modifications, then work my way from there. But when do you pass the line of to much treatment?

There almost no traffic outside the new location, but there is a fan on the adjacent building that generates some (not much) noise. I´m going to change the windows to double glass to take care of that problem.

I was thinking of putting some diffusors in the ceiling over my desk but not on the walls. Maybe I´ll have to reconsider this?
In another room I´ve heard some great results of Rockwool audio-plates (Polar) cut into the compartments of a Ikea shelf that stand along some of the walls. These are easily moved and can also be mounted to the wall when you have found the right place for them to stand. But I have to try it in this room to see if it works.

Thanks
Morten/Redroom
Old 16th August 2007
  #12
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Morton,

well I'm going to place diffusors on the side-walls / ceiling at the first-reflection points .... absorbtions is IMO for corners/edges .... my room has enough absorbtion ...

QRD diffusors ( waveweavers ) and "normal" diffusors are the opposite on absorbtion ... when you fully absorb .. you'll only hear "the speakers" ... but with diffusors and waveweavers you could create an sound-stage / image with reflections ..... at least that's what i've been reading/hearing .... I'm going to expiriment in the next month ... all added with prof. accoustic analyzing help ...

but for all I'm interested how it sounds/feels ...

some images from QRD-diffusors :
Attached Thumbnails
New mastering room-dif01.jpg  
Attached Images
New mastering room-dif07.jpg 
Old 16th August 2007
  #13
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Ethan Winer's Avatar
 

Quote:
Originally Posted by inlinenl View Post
I'm going to place diffusors on the side-walls / ceiling at the first-reflection points .... absorbtions is IMO for corners/edges .... my room has enough absorbtion
I think that will be a mistake. Absorption is a better choice than diffusion for first reflection points, unless your room is very large. A better approach is to analyze the decay times versus frequency in your room, and tweak whatever you feel is absorbing too much.

--Ethan
Old 16th August 2007
  #15
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lucey's Avatar
 

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Quote:
Originally Posted by inlinenl View Post
accoustic treatment ( diffusors ) from vicoustic is much cheaper then RPG .. check their products ..... I just orded a sample of 8 diffusors ..
.
Cheaper? Yes. But even 1/2 as good? I doubt it. Look at the pattern in this, it's not right. The Skyline has far more variety and intentional science in the pattern. This is a rip off design, so yes it's cheaper with no RnD and not the right patterning.

Look at their bass traps, "6 of these will treat a room" and what are they? Auralex LENRDs ... which are darn near worthless.
Old 16th August 2007
  #16
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And it should be pointed out that his take on early reflections a drastic departure from the vast majority of acousticians.


Greg Reierson
Rare Form Mastering.
Old 16th August 2007
  #17
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Ok, this maybe get's interesting .. let's cut some wood .....

Ethan : thanks for replying / enjoyed all the info on you're web (100% OK ) .. could you maybe give some ideal reverbtimes in a masteringroom :

we just did the first analyzing in my room .. and the tech guy who is helping me ... is saying that the absorbtion currently in the room is okay ... and he is in favour of getting in some more hard-surfaces/diffusion ... that should give my nautilus 800 some more stage .. but he already was impressed with the sound/detail off the current room en freq response .. I trust him, otherwise I would not have hired him to do it ... and will follow his advice ..... finally in the near future I can hear the difference between the two versions ..... and judge what is more pleasing and giving better results ...

"Sir" Bob Olhsson .. thanks for you're input ... if I understand the article correctly ... the writer is also in favour of some calculated diffusion in the first reflection zone < 50Ms ..... Are you sharing that view ... and do you find it more natural sounding in you're mastering-room ... "sound is reflection"

Lucey : that's why I orderded a sample pack ... I will hold it close to the PRD diffusors / skyline maths ..... I was also asking where's the catch ????? but maybe the working area is a bit different .... otherwise lost some cash ... how are you're stocks doing ..... ... stocks are not ZEN / they pay for bombs .... ( just kidding )

Greg what's you're opinion ...
Old 16th August 2007
  #18
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Part 2.....

I've spent the past few hours listening to music without my usual early reflection absorbing side panels. I have to say it's an interesting experience. Everything certainly sounds wider, though a sum to mono is still a very small point in space in front of me. The really interesting thing is that great recordings still sound great, if a bit more open, but mixes that were on the edge of being too strident or brittle are unbearable. That could make it a hard choice to live with for the long term. OTOH, a good monitoring system is supposed to reveal problems...

Sweeping a function generator up the spectrum reveals some pretty strange comb filtering going on, but it may be more of an academic issue than a practical problem.

I think I'll keep it this way for a little while longer while I think of a way to cover those old mounting brackets....


Greg Reierson
Rare Form Mastering
Old 17th August 2007
  #19
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Quote:
Originally Posted by everyday View Post
60% better???

How did you measure it?
The golden mean should be 61.8% better!

DC
Old 17th August 2007
  #20
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Quote:
Originally Posted by dcollins View Post
The golden mean should be 61.8% better!

DC
Glad to see you again DC, I was becoming the annoyed quipper.


Livingstone I like the look of those, nicely done.


Inlinenl my stock, singular, was up .40 today then down in the after hours. Holding tough all week. No bombs, just a little something to heat and cool your car seat and in 2 years replace the Heat Pump and the Alternator, plus make electricity from all waste heat. ARGN.
Old 17th August 2007
  #21
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Bob,

I have to disagree with David's basic premise stated at the outset:

"early reflections provided by the room are 'good' data for our hearing, and they contribute mightily toward the perceived timbre and spatial details of the music coming from the speakers."

There are two camps. One side believes that the room's contribution to what you hear is useful and valuable, and the other side is adamant that the goal is to reduce the room's contribution as much as possible. It's difficult to proclaim anyone "wrong" when it comes to subjective stuff like this, but I am firmly in the group that prefers to minimize the room's contribution for several reasons:

1) When your room contributes its own resonances and comb filtering, everything you play is tainted in the same way.

2) Imaging, and the ability to discern detail, is always made worse in the presence of early reflections.

3) Avoiding the room's own sound gets you closer to the original mix engineer's intentions.

4) In rooms the size many/most people use these days, any room tone is bad room tone. Boxy and boomy are two terms that come to mind.

However, things change in larger rooms - like those I bet you're used to working in. heh When the ceiling and side wall reflection points are ten feet away or more, the main problem - comb filtering - is reduced enough to be less damaging.

--Ethan
Old 17th August 2007
  #22
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pan60's Avatar
 

Quote:
Originally Posted by Ethan Winer View Post
I am firmly in the group that prefers to minimize the room's contribution for several reasons:

1) When your room contributes its own resonances and comb filtering, everything you play is tainted in the same way.

2) Imaging, and the ability to discern detail, is always made worse in the presence of early reflections.

3) Avoiding the room's own sound gets you closer to the original mix engineer's intentions.

4) In rooms the size many/most people use these days, any room tone is bad room tone. Boxy and boomy are two terms that come to mind.

However, things change in larger rooms - like those I bet you're used to working in. heh When the ceiling and side wall reflection points are ten feet away or more, the main problem - comb filtering - is reduced enough to be less damaging.

--Ethan
this is my feelings as well!
Old 18th August 2007
  #23
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The most common perception among the better known designers is to control the room's contribution, not eliminate it. Overly dead rooms don't help. However, RFZ (Reflection Free Zone) at the listening position is the typical choice, and I tend to agree.

With the special case of wide dispersion monitors (not just talking about banjo mart models with dome tweets) in a particular sized room with particular geometry, reflective first reflection points on the side walls (still not floor or ceiling though) can work for some applications, such as audiophile listening rooms, but it still wouldn't be my first line of defense for a studio environment.

Another thing overlooked in this thread has to do with QRDs on the side walls at the first reflection points instead of absorption. The problem lies with the 16 foot wide room. Assuming you may have a range of at least a couple feet in the middle to account for your head and regular ergonomic movement, and the depth of the QRDs themselves, and you're lloking at 6.5 to 7 feet of distance between the listener and the diffusor, which is significantly less than the minimum required for the diffusor to reach it's optimum diffusion. You need at least about 10.5 feet or you end up with a non-uniform spread, and furthermore, some phase issues from the interaction of the wells that essentially causes comb filtering up close.

The next problem is with the effective spectral range of the typical QRD. You also end up with high frequency specular reflections (non-diffuse) which would have been eliminated with absorptive treatment, thus you haven't solved the problem for high frequencies - only the midrange (important though mids may be).

Two solutions for the latter problem would be to use abfusors, which have absorption on top of the diffusors, taking care of the high frequency problem, or using a diffractal, which essentially puts a smaller diffusor (a la RPGs flutter-free) on the surface of the wells of the QRD. Essentially this is a multi-band diffusor, again, handling the highs. This does not, however, solve the former problem of being too close to the diffusors.

The other thing to mention is that you can use reflectors to alter the room geometry to send reflection from the side walls into a diffusor or absorber in the rear of the room. This could be another option for creating a RFZ, though you need to make that choice based on the whole room plan, taking into account total absorption.

We also have ignored the contribution of low frequency early reflections which aren't handled by QRDs, reasonable depth frictional absorbers, or thin plywood (or other low mass) reflectors.
Old 18th August 2007
  #24
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Sorry to High-Jack this thread Morton,

thanks Jay for you're balanced reply on the use off QRD on the sidewalls ..... I get you're point .. have to read a few time before it get's to me ....

what about the use off QRD on the wall behind the speakers ( placing them outside the RFZ ) and on the ceiling ( inside the RFZ ) .. do you have any thoughts on those places .... I really would be interested to hear ..

what about reverb-times in a room .... what is ideal ... do you have any info on that or some interesting link ... the data we collected in my room
until now ... was a bit hard to get ( still some noise form outside slips in through the airco-connection ) so the meassurement was not
perfect .. we will do it again soon ...

currently my reverbtimes are pretty short I Guess .. I just don't have any actual data to compare ???? ... de room is OK to work in .. low-end is
pretty tight .. because the full-range/basstraps work out great ... but just would like to have some data from a different mastering-room to compare ..
you see I'm trying to get on the "cheap" some extra info on room-treatment ...

just had for a few days a 749 .... oops it still hurts ... no comfort ... all looks/comments when you park it ... :-)
Attached Thumbnails
New mastering room-gemiddelde-nagalmtijd2.gif  
Old 18th August 2007
  #25
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Keep on high-jacking!!!!!

This is all good stuff for me.
Old 19th August 2007
  #26
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Quote:
Originally Posted by jayfrigo View Post
Assuming you may have a range of at least a couple feet in the middle to account for your head and regular ergonomic movement, and the depth of the QRDs themselves, and you're lloking at 6.5 to 7 feet of distance between the listener and the diffuser, which is significantly less than the minimum required for the diffuser to reach it's optimum diffusion. You need at least about 10.5 feet or you end up with a non-uniform spread, and furthermore, some phase issues from the interaction of the wells that essentially causes comb filtering up close.
IIRC, the Cox and D'Antonio book mentions a minimum distance of three times the longest effective wavelength of the diffuser. The depth sets the diffuser bottom range. With then feet distance, that's a 1 foot deep diffuser / ~340 hz. (according to this calculator) Many commercial diffusers are not as deep and don't need as much distance.


On topic, absorption is usually the way to go on first reflection points. Short echoes up to 20 ms should usually be suppressed as much as possible. (at least in the normal way of doing this). The first region of the impulse response of the room is potentially more destructive than the later decay. Cleaning up the beginning suppresses comb filtering. Diffusion can be used to this means, by providing a rich field of short echoes. This is more often used in recording rooms where it helps support the acoustic sound without the traditional massive comb filtering of short echoes. In listening rooms, diffusion is typically used to spread the later part of the echoes, the reverb sheen. This can, I believe, be tuned to taste as the long reverb is clearly separated from the beginning of the sound by our brain. When the bass and midrange is under control, the problem is usually to get more reverb, not less. Page nineteen of this excellent RPG pdf have a nice illustration of a desirable impulse response. The treatment is achieved with a combination of absorption and diffusion.

(disclaimer: I'm just an amateur so please correct me if there's any errors!)


Regards.

Andreas Nordenstam
Old 19th August 2007
  #27
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Quote:
Originally Posted by Lupo View Post
IIRC, the Cox and D'Antonio book mentions a minimum distance of three times the longest effective wavelength of the diffuser. The depth sets the diffuser bottom range. With then feet distance, that's a 1 foot deep diffuser / ~340 hz. (according to this calculator) Many commercial diffusers are not as deep and don't need as much distance.
Don't confuse the depth of the diffusor itself with the distance required for the scattered sound to combine to create a coherent wavefront. The Cox/D'Antonio book gives the example that since most diffusors used in listening rooms are effective above 300-500 Hz, a minimum distance of 3 meters is recommended.

You are right that this is based on three wavelengths, which at the lower frequency limit of 300 Hz would be 11.3 ft or 3.39 meters. The most effective range of the typical QRD that we see most often does not quite reach down to 300 Hz, so you can get by with my original suggestion of about 10.5 feet.

It is frequency based, so you could be closer to RPGs flutter-free than to the typical QRD we are used to seeing on control rooms. Converseley, a large diffractal such as the one in the back of Gateway Mastering requires additional distance for the lower frequency components to be most effective. For custom designs, you need to do the math.

Also, your post suggests, whether intended or not, that the smaller commercial diffusors need less distance since they are less deep, but this is not quite true. It is not three times the depth of the diffusor that is needed, rather three times the wavelength of the lowest frequency that is effectively diffused. This can be calculated by dividing the speed of sound by the frequency.

In metric units, the speed of sound is usually quoted between 340 and 344 m/s, and the resulting answer would of course be in meters. In English/American units, it is usually given to be 1130 ft/sec, though some will use an 1100 ft./sec approximation to make the math easier. The answer in this case will obviously be given in feet. This may have been the source of your confusion above. I think you may have plugged the info into an equation with metric units but labeled your answer in imperial units.

The speed does in fact change with factors such as elevation, temperature, and humidity, so to be completely accurate, you would want to take into account the average temperature and humidity of your room, plus the elevation of the studio. Unless you are in Denver, outside, in the middle of winter, however, you can usually get by with the commonly given figures.
Old 20th August 2007
  #28
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Dave Moulton did a simple demo for me in a bare room that turns most of what we thought we knew about acoustic treatment and imaging right on its ear.
Old 20th August 2007
  #29
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Quote:
Originally Posted by Bob Olhsson View Post
Dave Moulton did a simple demo for me in a bare room that turns most of what we thought we knew about acoustic treatment and imaging right on its ear.
Sounds interesting Bob, what did he do and what did you think?
Old 20th August 2007
  #30
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Hello Jay!

Thanks for the corrections!

>Also, your post suggests, whether intended or not, that the smaller commercial diffusors need less distance since they are less deep, but this is not quite true. It is not three times the depth of the diffusor that is needed, rather three times the wavelength of the lowest frequency that is effectively diffused. This can be calculated by dividing the speed of sound by the frequency.

Sorry. What I meant was of course effective depth, not actual depth. The figure I posted was based on the presumption that the QRD had a fair bit of "virtual effective depth" through the design. (example: a QR sequence based on seven have a maximum number "four" in the sequence, giving a 4:7 "free" effective depth). Note the use of the approximate sign - "~" im front of the low freq number. Now that I look at it again the numbers does seem odd indeed! It was just an example though. The reason I jumped on the depth as the important value is that the primary design parameters are: slat width for high frequency, slat depth for low frequency.

The point is still the same: there are designs that works in the closer field and designs that needs more than 10.5 feet. I think that rule is a bit outdated since it only works on one design frequency. It's a good starting point but not applicable in all cases. If someone builds a two feet deep trap, 10.5 feet will be too little. Given the thin diffuser stuff with 4" and less depths, some are as thin as two inches, that's too shallow to warrant 10.5 feet -- no?

So what I'm trying to say is that "a distance three times the wavelength of the lowest frequency" is a better starting point than "10.5 feet".


>For custom designs, you need to do the math.

Agreed!


>The speed does in fact change with factors such as elevation, temperature, and humidity, so to be completely accurate, you would want to take into account the average temperature and humidity of your room, plus the elevation of the studio. Unless you are in Denver, outside, in the middle of winter, however, you can usually get by with the commonly given figures.

Elevation changes are nulled out for all practical purposes as the density balances the pressure. Quote wikipedia: "In the Earth's atmosphere, the speed varies with atmospheric conditions; the most important factor is the temperature. Air pressure has almost no effect on sound speed. It has no effect at all in an ideal gas approximation, because pressure and density both contribute to sound velocity equally, and in an ideal gas the two effects cancel out, leaving only the effect of temperature."



Andreas
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