help with control room treatment

[angeltone]

hi guys,

peeping at this great forum the last weeks i dare to present you my room problem now.

i want to make acoustical adaptions to my acoustically completely untreated (!) control room (which in fact is no real control room at the moment because control is rather missing). problem is that the premises for this project are a really restricted. for reasons of mainly lack of time AND skills, i can not account for rebulding the room not even making modules like bass traps myself. i would LOVE having instant solutions like ethans bass traps here in europe and would be eager to buy them, but i fear i'll have to make do with VERY expensive products from rgp et al. that i can get here.

nevertheless i would be deeply grateful for your experts opinions of how to treat the room basically to make it working. absorption, bass traping, where to put what and how much of it. i am especially concerned with what the high ceiling is doing to the rooms acoustics and also about the slight irregularities' effects.

here are the facts how the room looks at the moment to complement the plan and pictures:

three walls are gypsum plasterboard, the window wall is mainly plastered red brick wall except the part right from the door which is also plasterboard. behind the plasterboard it's also red brick. floor is laminate parquete.

all measures in centimeters (the brackets contain the converted inches for you)

room height: 345 (135,8)
room measures (see plan): l=454 (178,7)/471 (185,4), w=432 (170)/435 (171,2)
console: w=250 (98,4), d=115 (45,2), h meterbridge=107,5 (42,1), h leading edge=75 (29,5)
window: w=141 (55,5), h=110 (43,3) starting at a height of 104 (40,9), distance to left wall 53,5 (20,8), distance to door 52 (20,4)
door wood: w=151,5 (59,4), h=263 (103,5)
cd rack: w=40 (15,7), d=20 (7,8), h=202 (79,5)
workstation: w=77 (30,3), d=50 (19,6), h=76 (29,9) with 17'' computer monitor
leather chair behind console
chairs fabric [2]: w=58 (22,8), d=78 (30,7), h=74 (29,1)
plexiglas table: w=35 (13,7), d=35 (13,7), h=35 (13,7)
racks: w=219 (86,2), d=54,5 (21,2), h=120 (47,2) distance to wall behind 24 (9,4), distance to right wall 182 (71,6), 2 keyboards and 1 piece of gear on the racks (see 3.jpg)
guitar amp: w=74 (29,1), d=35 (13,7), h=110 (43,3)
ventilation: w=24 (9,4), d=13 (5,1), h=40 (15,7) starting at 263 (103,5), distance to the right wall 124 (48,8)

monitors: genelec 1031a

i'm curiously looking forward to hear your thoughts and ideas.

thanks in advance

istvan

[Ethan Winer]

Istvan,

> i would LOVE having instant solutions like ethans bass traps here in europe <

We sell MiniTraps worldwide, and have shipped many to Europe.

Besides all the good advice you'll find in this forum and elsewhere on John's site, also see my Acoustics FAQ, second in the list on my Articles page:

www.ethanwiner.com/articles.html

--Ethan

[angeltone]

ethan, thanks for that hint. i will pm you about the shipping to europe thing, maybe it makes sense for me.

i studied those acoustics FAQ and other sources, but as a lot of people i have my own ideas about it, but am not completely sure and want to know what other more experienced people propose. especially the not DIY appoach makes it much harder to find solutions.

thanks
istvan

Istvan,

> i would LOVE having instant solutions like ethans bass traps here in europe <

We sell MiniTraps worldwide, and have shipped many to Europe.

Besides all the good advice you'll find in this forum and elsewhere on John's site, also see my Acoustics FAQ, second in the list on my Articles page:

www.ethanwiner.com/articles.html

--Ethan

[angeltone]

ok, maybe my question was a little bit too vague so nobody except ethan had mercy with me. i try to refocus on some points that are unclear to me.

1. the back wall is a bit nonparallel angled (probably all walls do show slight irregularities). when intended this should be a good thing, but unmeant as it is, what effects on the acoustics does it have (making the room a bit assymetrical)? when i install absorbers on the back wall could this be a problem?

2. the ceiling is relatively high for a room like this (11.32 feet). i get the impression that when the talk is about "small control rooms" normally they are much lower. does the heigth have any effect on how the room should be treated? does this require some specific absorption?

3. how do you deal with the window and the big wooden door when installing sidewall absorbers (a la john sayers)? is there anything special i have to consider?

i very much appreciate the help i hopefully get here

thanks
istvan

[knightfly]

Hey Istvan - lets see what we can do here - I think part of the lack of response was due to the fact that most of our members seem to be very much into DIY, that's probably a lot of why they come here (that, and the winning personalities of the moderators )

I'll cover your questions in order, sort of -

1. The slight asymmetry of your room won't have much effect even without treatment, and when you put absorption on that rear wall it will not even be noticeable.

2. Your ceiling height is a wonderful change from the low ceilings a lot of people are forced to deal with in basement studios. The axial modes of your room as it is now, show only a possible slight coloration at about 150, 200 and 300 hZ. There is also a slight imbalance at 20-25 hZ, if you even make noises that low frequency - all in all, modes should NOT be a problem in your room.

3. I know how to answer this for a DIY guy, but who is going to build these absorbers? And, are you talking about the splayed, free-standing slat absorbers such as the ones on the side walls here?

http://www.johnlsayers.com/HR/index1.htm

You've already stated that you're short on time - most, if not all, the acoustic treatments we recommend take a fair amount of time and a medium skill level with tools to complete. About the only QUICK way I know of doing this would be to show the site above to a professional cabinet maker and ask them what it would cost and how soon you could have them.

the main thing you need to do in that room is to get rid of all the parallel surfaces, either by absorption or by re-angling them. The sidewall absorbers do both. This not only kills flutter echo, but (when they're properly oriented) creates a Reflection-Free Zone for mixing (assuming you do something similar to the ceiling)

Some people in your situation just go spend a lot of money on "studio foam" - I won't recommend that option because it almost always leaves people sorry they spent the money. The DIY options we use are several TIMES as effective and more uniform in absorption qualities, so you get a much more balanced reverb time in the room for less money. That's mainly why we're here.

Your window (looks like it's already double glazed and splayed vertically, from the picture) could be controlled by re-directing its reflections - if you could find a large sheet of plexiglas and mount it on feet, similar to a gobo, you could still see through the window but have the plexi shunt reflections to the rear wall. This could be built into a slot absorber at the same angle, the slots being above and below the window - just don't SEAL the plexi part, or you'll degrade the isolation of the window (if it's already got two panes)

The doors could concievably get angled slot absorbers built onto them that would also redirect reflections to the rear. You'd just have to use fairly light materials (not really thick boards) so the hinges didn't fail.

Beyond that, I'm not sure what to tell you, unless you want to (or can) build, or have built, some custom carpentry. I hope some of my thoughts helped in some way... Steve

[John Sayers]

I agree with Steve here - I was leaving it up to Ethan because he makes prebuilt units that you could purchase and mount under his direction.

Most of our solutions require you to be a DIYer or have a friend who can build it for you.

cheers
john

[angeltone]

thanks!

especially steve and ethan - who provided me with further help via e-mail. yes your remarks helped me a lot to see this clearer!

steve, i was referring to john's slat absorbers for the side walls because i know you are familiar with them but more thinking about something like
http://www.rpginc.com/products/abflector/index.htm

cheers
istvan

[giles117]

Once again the number one problem with treatments such as this abflect are they are abosorptive. When you over absorb the room you end up on the other side of the treatment scale. A dead dull lifeless room. That is not what you want.

Hence the slat wall absorber John has developed, you get the absorption desired without the total deadening of the room.

Bryan Giles

Read this clearly.

The Abflector™ is a novel and economical internally hinged, upholstered absorptive panel.

Standard Unit Construction


4' height x 1' 7'' width nominal (4' x 1' 6-5/8'') x 5-11/16'' deep

Guilford of Maine FR701 #298 fabric

6 lb. density fiberglass