I got a question

hello, I've looked through the forum a bit and it seems like everyone is building there controll rooms with the sidewalls angeled 6 degrees. and I was just wondering why is that?? wouldn't it be easier to put lenrd bastraps in the corners at ordenary walls. why I'm wondering this is because i am planning to build a rectangeled controllroom and flush mount the speakers 60 degrees but would there be a problem if my walls isn't 6 degrees then? would aprecciate it alot if someone answered this. sorry for the bad english Im from sweden

hi fackl1,

sorry for the bad english Im from sweden

my english is even worse - you guys up there in the north at least grow up with english tv-program, around here it's translated to german :? Ok, i'm not the most advanced around here, but let's go... in order to get a reflectionfree zone (rfz) at the mix position, each sidewall is angled by 6° from axis. this will direct first reflections from the sidewalls to the backwall where it can be absorbed (a must in small rooms) or diffused. it also kills flutter echoes which build up between parallel walls. If you are dealing with an existing room, you can handel this with slat resonators which give all advantages already described and at the same time also trap mid/low-mid frequencies. look here to learn more: http://www.saecollege.de/reference_material/index.html http://www.johnlsayers.com/HR/index1.htm have fun! dreamer

hehe yeah.. Ones I was in a turkey hotel and turned on the tv and I saw the swedish series "Beck" translated into german.. so damn funny I think i go with that 6 degree wall. but do you think it will work with auralex lenrd basstrapps in the back corner? I know they're pretty small but i will get them for a nice price so thats why im wondering.. That SAE page is a treasure :D thanks alot for the help

not from experience - just what i read on some other forum. (but from trustable guys who did measurements): normal lenrds will not be very efficient to the low end, but megalnrds are good. a maybe cheaper option would be rigid glass/rockwool across the corner. for more info have a look at this: http://forum.studiotips.com/viewtopic.php?t=537 cheers dreamer

Good call on the studiotips thread - However, on wall splaying - 6 degrees each side (or sometimes even 6 degrees TOTAL) will take care of flutter, but isn't enough angle to take care of early reflections (the RFZ, or Reflection Free Zone, principle) - for that, you need greater angles. I did an example of testing a design for early reflection possibilities, it's near the bottom of this page - http://www.johnlsayers.com/phpBB2/viewt ... =8931#8931 Basically, the side walls need to be angled enough so that any first reflections from either speaker to walls will be re-directed AWAY from your head, making that sound path at least 7 meters LONGER than the DIRECT path to your head - this is trickier than it seems, but is doable. IF you don't have enough room to spare for the steeper angles, you need to use the "mirror trick" - this is where you have a friend hold a mirror flat against walls (and ceiling) and move it around the room - anywhere you can see either speaker in the mirror while sitting at the mix position, you need to place sound absorbent material, such as (at least) 4" (100mm) thick acoustic foam, or 2" or thicker fiberglass or rockwool - Hope that helps... Steve

hi steve, in the thread you refer to, are you talking about the picture you made where you raytrace the soundreflections from the rear soffits? if so i do not understand your comment, cause fackl1 didn't say he'll build a surroundroom. or is this the case, also for stereo? (cause as i see this pic, you wont have such walls in a 2-mix room) what did i miss? :? please shed some light on thís. thanks dreamer

Yeah, actually that method also works just for checking angles of front half of control room - if you draw a line from either speaker center to each end of a wall section, then draw the reflected angle from each of THOSE lines (if incident angle is minus 14 degrees, reflected angle will be PLUS 14 degrees, relative to a perpendicular line off the reflecting surface) - then, after drawing the reflected angles from both ends of that wall section, everything BETWEEN those two reflection lines is a first reflection zone. If that includes your mix area, you either need to change the wall angle or absorb the reflection point. While I did that drawing based on a surround room, it still applies when angling front walls for RFZ - ceilings too... Steve

ok, now i'm confused...cause this is what i thought when i first came to this board and saw all the layouts. then i found a thread which said that the main energy is fired in a relatively small area off axis from speakers and the rest is neglectable. this should be why a design like the one below works. i'm sure i mixed up all gathered info and got things wrong. i woukld appreciate if you could explain this. thanks a ton.

Ok I tried to speed read this thread so if my comments are a tad off base slam me. But anyway. That design is the way my studio was built and the Design works. Perfect no, but it is 98% effective for getting a GREAT sound. :) Save for as Steve said some minor early reflections. Now Lenrd's in the corner to trap bass.....Well I am a real life example of ... I tried it and it does not work. They really do not absorb the bass effectively enuff I dont care what the specs say. My room is the exact design there save for the Patio Door in place of the slat resonators. I have gotten some excellent mixes out of this room that translate extremely well. My rear walls are filled with 4" rockwool (4pcf) And my bass is flat at mix position from 40hz on up :) on the meter.

hi bryan, bryan wrote:

Save for as Steve said some minor early reflections.

steve wrote:

....but isn't enough angle to take care of early reflections.....

maybe i got that wrong, cause english is not my native language? if so i apologize. please read the last 2 posts again - it's all about splaying walls by 6 or more degrees. i attached another pic to make it clear. so... whats happening to the early reflections (red line in pic)? is it as i read somewhere neglectabel cause of minor soundenergy or is it something to avoid as my first thought was when i saw it. greetings dreamer

Í think i skip the lendrs and go with the rockwool. I'll go do that mirror trick and wright up a blueprint and then post if and see what you think about it..if i could just find that prog you guys are using...thank you

the most common her is smartdraw: www.smartdraw.com

Ideally early reflections are something to avoid. In the case of a smaller room there are tradeoffs. The question is are the ER really a pain in the smaller 6 degree splayed room. My personal opinion having mixed in my room for over a year now is NO!!! They are not a pain. If anything ER in a square room cause more headache as they are also mixed with flutter. So far as your raytracing, I doubt it is that dramatic. Which is why the guys said use a mirror to see the Drivers of the opposing speakers from your mix position. What I did while typing this post was to do the mirro deal and see how much of a problem the ER's might be for me (My mixes say that I have no major problems. My top end is nice and clear. I could not see my opposing speakers anywhere on my angled walls while i was seated in my NORMAL mix position. Of course YMMV. I know we all want perfect and when we have the space we get perfect but this room design works. I recommend not panicking and instead, taking the word of people who have built their rooms based on this 6 degree per side splay, that it works. Blue Bear is one such guy. I am another such guy. My mixes are basically what you mix is what you get. I can understand the apprehension, I had tons of it as I was putting up my studio, but that 1st day of firing up the speakers was a WOW day. I went nuts. I was raving and have not stopped. I have helped a bunch of guys since then get it together..... So rock on and build this thing. :) as a refresher.. here is the design I built. I did actually install a door. LOL

thanks bryan,

YMMV

what's that? :D BTW, how's your 5.1 room is doing - is it finished? do you have pics? cheers

Your Mileage may vary. Meaning depending on how far your speakers are apart and where they are located in the soffits will change your results with regards to the mirror test. Surround sound studio is not done. Ened up stopping shortly after breaking ground. I remain optimistic, however we had to approach it from another direction. Will keep all posted. (Hence my silence on that subject. :) ) Looks as if we will be buying up 2 empty lots to expand the existing facility and apporaching it from that direction. I assumed I'd be done by now but had some major flooding issues. Once is enuff for me to not wanna continue to build it in the basement.

I skipped the mirror test since my plans of the room wasn't correct since I wouldn't have no doors on it :D Here is a blueprint of the tiny room wich im gonna build a controlroom and a vocalbooth in. dont know how im gonna make it fit but someway it will.. the vocalbooth will be about 1x1m or something.. please make suggestions about were/how to angle the controlrooms walls or any help about anything would be needed

Ah you Metric System folks. LOL Just to verify your entire length and width is available???? With the fireplace on your left side being the only room obstruction??? So my purposes you have a 12x14' room :) Decent size. My room was 13x11. 1 foot diff. Just size to fit. :) 6.4' from the front wall to fireplace. and how far out does the firplace protrude in m or cm?? You can easily fit this plan with the front of the control room at the top of th4e plan. where the Firplace is, the resonator wall would stop and you will need to place some thick (4") absorption on the side of the fireplace to trap reflecions. :) Other wise this is quite doable in your space. would be nice to have a fireplace in the studio. :)

just did a quick "copy and fit" bryans layout into your plan. i wouldn't sacrifice floorspace for a booth.

Yeah you can always go to the rear of the room and sing into a mic. ;)

hehe yeah I realized that map was pretty useless :D nice dreamer! now I just put rockwool and simiular from the middle of the room and down. right?

depends on available space, but think about something like this in the rear wall. (one of john's rearwalls). or you just put up thick rigid fiberglass. maybe bryan has more suggestions.

For your depth of room that is accurate and what dreamer has for your rear wall will give you excellent bass trapping. You could use rockwool in place of the 703 in front of the 2 slat walls in the center of that rear wall design. The brown panels you see angled in front of the hangers for your room will be 4" rockwool (semi rigid 4pcf)

looks really nice! thanks alot. now I only got two more questions for you =) 1. what should I use for the hangers? chain or rope or is it not relevant? 2. I found a couple of boards in my grandparents garage. some kind of isolating material and I cant find out what it is. they are about 3 cm, and quite hard. so i figured it was eather some kind of floorboard used for floatingfloors or mineralfiber or something.. anyways can someone tell me what it is by looking at theese pics?

For hangers, whatever works for you. No rule there. Some people use rope, others have used wire, etc.... Just so long as the insulation doesnt fall out the hanger. :)

this reply will take this thread back a bit, but I wanted to post something to interest anyone building a 5.1 theatre, like GILES. I install a few a year. Basic, low to mid level systems. I use RBH speakers, and a few years ago they came out with "Virtual drivers". Basically a huge speaker driver (magnet and coil) with out the cone. Its only purpose is to shake. I have two bolted to my floor. Driving them with a 200 watt sub amp. I know it could be argued that if you have enough sub woofer, your room will shake. Fair enough, but whatever- I love my floor shakers. I sold a set to a guy who had them bolted to the bottom of his couch. I seen him a few months later in a store and said, "hey how you like those shakers" this big grin came acrossed his face and he gave this thumbs up. Enough said. RBH quit making them as there was not a big demand, but I hear they are out there. I would say build you theatre the way you would, and If you want to add a fair amount of realism to the room, consider installing some of these. d