Ein - For shallower CR's, that should be more broadband trapping (rigid fiberglass with cloth) or possibly a variable depth slat resonator - your room is borderline whether diffusion will be good there - you could probably use a large, centered Polycylindrical absorber there also. If your head will be less than about 11-12 feet from the rear wall, then stick with broadband absorption - that could be just a flat trap, spaced about a foot off the wall and intersecting the splayed side traps.
Dos - Although Adams can be soffited, it gets a bit tricky - Barefoot has some drawings either in Acoustics or Speaker forum on that. If you're dead set against it, leave room for several inches behind the speakers and put 3-4" of rockwool or rigid fiberglass behind the speakers, and space the material off the wall by a few more inches. Check out the wall bounce calculator at the Acoustics forum, play with absorption/positioning and see what a difference in response can be had... Steve
Thanx for the input and you always have a place to stay in Germany...
Um, well I am taking the hangers down! After even more study of this site I realized that I should have put the floor in first. Plus, there is just no way to work around them now. My entire studio will still be a hybrid between the perfect studio and the budget and time constraints studio. Initially I was depressed the more I came here and realized that you can't just wing it. But if you maintain your attitude you should be able to bounce back and kick ass....which of course is where I am at now!
All the walls in the plan are sheet rock just a single layer. As you can see from the pics I am using metal studs with 10 centimeter acoustic fiberglass. Realizing now that the floor should be underneath these walls...oops I am floating my floor inside them and will add all my resonators and bass traps on top of the floor. The existing floor is vinyl and I need to raise it about 24 cm so I am using bricks and then rubber under my 6x8 cm joists then a type of german particle board then wood flooring. Then I will build walls as depicted on the SAE site with built in resonaters and bass traps and put the ceiling on top of that frame completely isolated from the extisting ceiling. Unfortunately the hangers have to go but can be added from the ceiling joists later. One cool thing I did with my home studio is put tennis balls at the pressure points between the inside and outside walls at key locations to keep the whole thing from moving.
Have yet to see a link for these - the only reference I have is pages 209-213 of Everest's Master Handbook of Acoustics, 4th edition - this book has several errors in printing, some of which I've probably missed - still, for the money it's the best single book you can buy. It's about $25 USD at amazon, or you can download an electronic (copy protected) Adobe Reader version for around $35 USD - I have both, and use the electronic version more than the paper version (search capability)
Basically, a poly is just a thin plywood membrane bowed over curved struts (similar to the ribs in a model airplane wing) - when filled with fiberglass, it becomes a pretty good low bass trap as well as mid-high diffusion. Do not use hardboard for poly's though, tends to sag after a bit. One simple way to build them - cut some arcs from heavy plywood, mount them on the wall, apply foam weatherstrip to the edges of the arcs to avoid rattles, place a full length cleat where the first vertical edge of the poly will go, bend the panel around the arcs, and fasten with a second cleat at the far side.
I know that's not much of a description, but it's late and I don't want to infringe on anything copyrighted - I would recommend getting the book, and not just for that - you'll use it a lot in your build (and before)-
You can do a google search on polycylindrical absorber, you'll get some help but not much on plans.
Keep in mind that you should be looking at the TOTAL picture in your studio - don't fall for the trap of building something cause it "looks cool", or is God's gift to acoustics. What you want is EVEN reverb times in rooms, or they sound funny. The way you get that is to figure out ALL the materials/devices in the room, sum them and see what your RT is for every frequency. They should all be similar. This is accomplished by using a combination of different treatments until you find a balance... Steve
Thanx man, yeah I have the book and did a search last night. The cool thing is you also achieve cambered lift with those traps....
I've got five friends now coming over today with a mind to build like hell. It can be tough keeping the plans ahead of all you buddies swinging hammers...ain't war hell...
I will let ya know how it is working out.
An additional comment on the books and this forum. I bought all the books available to me including Mr. Everest's and am on the net a lot but I am paying rent on the space so I have to get moving so it's always "Oh crap I could have done it this way!" And I have read the posts about doing it right the first time but, when you have five and six band members and friends showing up every weekend to kick ass you have to keep the momentum going. And I can chalk it all up to experience. Finally, it's not so hard to do some things over with five dudes and six cases of German Bier
Thank you so much, I hope to implement everything you are suggesting. And to anyone reading this who makes mistakes along the way remember, it ain't over til it's over!
Closing in the ceiling tonight and will post some pics. One Question though..In all the SAE and many other sources it shows cloth in front of the insulation within the slot resonators and bass traps, can I use carpet there? I am in Germany and the cloth thing is becoming a huge PITA and is more expensive than carpet. Would the carpet be too reflective for that application?
The cloth is factored into the formula for slat resonators, and from what I've read it is important to have acoustically similar material in that position - about the only thing I could suggest is to build one and test it (as best you can) to see what it does compared to what the formula says it should do -
BTW, did I remind you not to use the calculator for slat resonators that's at the SAE site? The corrected one is posted in the acoustic forum... Steve
Finished the first pair of slot resonaters, there is one opposite this one and will build the second pair behind the door in the corner partially in front of the hangers
In the second pic, is that your control room, and is that the CR to live room window to the left of the ladder? Because if it is, you have the slats BACKWARD - the slats should be closest to the wall at the rear (as you're seated at the mix position - take a close look at the drawing at the bottom of the page here -
That's awesome...this is a combination letter of appeciation and suicide note....
thanx
FU*%!
But as you look at the damn drawing of just the resonator it goes from left to right and we all know that corresponds to front and back respectively...
One thing about building a studio is.....it's not worth anything if you don't do it twice...
Panel traps would be fine around the edges of the room, but overhead (mix room and often live rooms too) you'd want broadband absorption - the so-called "cloud" of rigid fiberglass or rockwool -
As to the "same angle" corner traps - if you mean the rear pair, they would end up probably far enough away from the mix position so as to return a diffused enough sound field to maintain a more live sound field but at the same time redirect enough of the speaker sound field NOT to cause problems with early reflections -
Keep in mind that ANY square corner will return sound exactly parallel to the incident path - this makes for a pretty short sound path from your head to the rear and back, and can cause smearing of the stereo sound field if it's shorter than about 20 feet round trip - using slat resonators in those rear corners would cut down a lot of the reflections back to the mix position without deadening the room too much - also, if the slots are not too narrow between slats, you would get a certain amount of diffusion off the interruptions between slats. For this reason I wouldn't make those rear units with too small a gaps (slots), even though it will raise the operating frequency.
The side wall slats are much closer to the mix posiition, and are there to redirect early reflections AWAY from the mix position while solving flutter echo problems caused by parallel walls - you want them to redirect sound to the REAR of the room, where it will mainly be absorbed by the rear wall trap and NOT be bouncing around in the front area where you're trying for a coherent sound field.
Sorry 'bout the suicide thing - I usually prefer "Death by Chocolate" - (It's an un-beLIEVably chocolaty Ice Cream, if you've not tried it) the stuff can almost make ya forget you just hit your barre chord finger with a hammer... Steve
- Although Adams can be soffited, it gets a bit tricky - Barefoot has some drawings either in Acoustics or Speaker forum on that. If you're dead set against it, leave room for several inches behind the speakers and put 3-4" of rockwool or rigid fiberglass behind the speakers, and space the material off the wall by a few more inches. Check out the wall bounce calculator at the Acoustics forum, play with absorption/positioning and see what a difference in response can be had... Steve