Ethan what would you recommend for treating an 11 x 11 studio with 8 ft ceilings?
I will mostly be recording acoustic guitar and vocals in this room.
I am building the mineral wool bass traps 4" thick later in the week and I'm making enough for all of the verticla corners and one 4' long to put horizontally in each lateral corner.
I also bought a few extra 2" thick panels for mid/high absorbers.
I will either apply foil facing to each bass trap or put 2" strips of foil tape 2" apart of the front of each trap to reflect some of the mids and highs.
Considering that I will be recording acoustic guitar in this 11x11 room how would you recommend I place the panels and should I definetly put foil on all the traps using FSK or will the 2" strips of foil tape on all the traps be enough? With the tape I will be basically be getting reflection from half the total surface area of each trap.
Thanks for your input. I will be getting my supplies tomorrow so I'd really appreciate any input asap.

Didn't I answer this somewhere else?

An 11 by 11 room needs as much bass trapping as possible. So fill those corners! And have the foil facing the room. The non-corner panels shouldn't have foil. I'm not there so I can't tell you precisely where to put everything. For recording in a small room, where all the walls are close by, you probably want to cover 50 percent of the walls.

--Ethan

Thanks for the input!!

Ethan, If treated properly can I get a good recording environment for acoustic guitars in a room this size?
So basically I should just use foil on all bass traps in verticle corners(where two walls meet) and horizontal corners (where ceiling and walls meet)
I would use no foil on the mid/high absorbers on parallel walls.
Is this right? I just want to make sure I'm understanding your recommendations.
I am really hoping that I will be able to get good acoustic guitar recordings in this 11x11 room. Thanks again for your input!

> Is this right? <

Right.

12 4" thick panels in a room that size will solve the low end for the purposes of acoustic guitar and vocal recording. You could go with as few as nine, but I wouldn't go any lower. You will need about ten more to control high end reflections, two on each wall and two on the ceiling. Abandon all hope of having any useful ambience in the room. Your goal will be to make a non-room. You will need to add any desired abmience artificially.

While it may be pretty, it's a mistake to concentrate the panels in the vertical corners; when you do that, you overtreat ther resonances in the lenght and width dimensions. Treatment should be evenly distributed among all the resonance subsets, namely the lenght-width, lenght-height, and width-height. Here is a plan for your room that shows 12 panels for low end absorption placed in an optimal configuration.

While I agree that you want to deal with all the dimensions, you can do the same thing by having the 4 vertical corners floor to ceiling and 1 panel at each wall/ceiling intersection - at the center of the wall.

In most rooms, the length dimension has the deepest issues and the width ends up being the one where you sit in the problem spaces. The height is usually the least of the offenders.

Matters not from a cost standpoint - same number of panels.

Now as far as ambience goes, you can still maintain some IMO. Just make sure you face all of the bass absorbers so that the other panels are the only ones doing any significant Mid/HF absorbtion.

If you want to use the room for tracking and mixing, consider the wall panels for Mid/HF control to be movable gobos that are hard on one side and soft on the other. That way, you can maintain some ambience while reducing slap with the hard sides out, make a 'booth' with them when needed, and use them soft side out when you want to mix.

When you have a small room like that, you need to be creative and every treatment needs to potentially do double duty. You need the ultimate in flexibility.

Bryan

For a mix room I agree totally (except for (0,0,2) which can be a persistent little guy), but for a tracking room, all bets are off since mics and sound sources vary in their placements. For that reason I like to recommend treating all modes equally in small tracking rooms like this. Also, I was under the impression that 3Dfan's room was for tracking only.

Good to meet you, Bryan. I look forward to more discussions in the future!

Hi David.

Not disagreeing with you at all. I agree that treating all the dimensions pretty much equally is important. If you did the panels as I described and had the mics anywhere in the middle 1/3 of the room, you'd have a wall/ceiling panel straddling to deal with the 0,0,2 directly in front, back, and both sides of you. You'll also still have all 8 tri-corners covered.

As for tracking only, I was speaking more generally. With your recommendation for 24 panels in an 11x11x8 room, I made the assumption that you were speaking more generally as that's awfully dead for a pure tracking room - small or not.

As you know, there are many ways to skin a cat. To each their own.

Bryan

I just want to get a nice sounding room for acoustic guitar and vocals. I don't want to over treat it either. I did that with the FBM and my acoustic guitar tracks sounded terrible. All the high end harmonics were absorbed and I had a serious low end problem that I could never seem to EQ out. I'm hoping with the reflection on the face of the bass traps I will have a nicely balanced room for recording my acoustic guitars.
I will be mixing and mastering in my home office where I have Whardedale monitors. I may make a couple of moveable absorbers to take down to my home office when I mix.
Again, I greatly appreciate all of your knowledge and helpfulness and how willing you are to share!!

If I glue the plastic (painters dropcloth) to the mineral wool and then put 2" strips of foil tape down the front of the panels with this increase bass absorption and mid/high reflection?

Should I not use the foil tape on the plastic glued to the mineral wool?

I forgot to mention, I also found some DIY bass trap plans where they recommend just using duct tape to tape the panels of 2" rockwool together.
Would this cause any problems as far as the duct tape reflecting too much or reducing the low absorption? I was thinking of using that new Gorilla tape because it is even stronger than duct tape.

Personally, I like them framed - from a durability standpoint and a HANGability standpoint.

Use some spray adhesive to bond them together and also to bond the plastic membrane. Use something relatively stout for the membrane - not just something like thin Saran-Wrap. Kraft Paper is another option that when bonded, will act more similarly to an FSK facing.

For framing, just try some metal drywall corner bead. You can make a complete frame, leave the sides and back open, and it's pretty easy to do - just need to be able to rivet it together. You get nice clean edges, it's sturdy but light, and you can easily screw into the back of the framing for hanging wires, etc.

Bryan

> 12 4" thick panels in a room that size will solve the low end for the purposes of acoustic guitar and vocal recording...You will need about ten more to control high end reflections, two on each wall and two on the ceiling... David M. French <

If the 12 4" panels are broadband absorbers, do you still think will need 10 more for high end reflections?

Is the foil tap attached to the plastic which is glued to the panel a good idea? Will it help with reflections and bass absorption or will it be too much?

Hard to say. I have no idea how it will react. That's part of the problem. Kraft paper is a known somewhat. Real FSK facing is another known when bonded.

While I'm sure it will reflect some of the mids and highs, I have no idea how much or at what frequencies - nor what if any membrane effect it will introduce in terms of where the peak in bass absorbtion would be.

Wish I could give you a better answer.

Bryan

Lionardk,

I personally don't. David is basically recommending to kill all the ambience and then reintroduce it electronically. That's one way to do it. I prefer to try to leave some of the natural room ambience in tact if it can be done while still controlling the other small room issues.

Bryan

Yes, Bryan. Thanks.

I don't want to kill all ambience and make the room dead. I've found that you can not do that and then just add reverb later when it comes to acoustic guitars. I want a nice balanced sound despite being in a small room. I guess I want to trap the excessive bass and balance the highs and mids.

Will it be ok to use the foil tape bonded to the plastic painters dropcloth which will be bonded to the mineral wool panel??
If this would decrease bass absorption then I won't do it.
Is the plastic dropcloth a good enough plastic to glue to the panel??
I am thinking I will try using Gorilla tape to hold the panels together because of simplicity and because the tape is REALLY strong. Should I glue the plastic dropcloth to the rockwool panels before taping the panels so the tape is on the outside of the plastic dropcloth?
I'll also take your advice and use the spray glue to glue the panels together also even though I'm also taping them together.

As I said previously, the problem with doing the tape and plastic is that you'll have absolutely no idea how it will react. It shouldn't change the bass absorbtion but you have no idea what it will do in the upper bass through the highs - precisely where your guitar has most of it's range.

Using a heavy kraft paper or real FRK/FSK scrim bonded with spray adhesive is a known quantity. It will peform similarly to a factory bonded FRK. It will give somewhat of a membrane effect that will provide a hump in absorbtion at around 100Hz. It will also effectively cut the mid/high absorbtion to about 50% of what it is unfaced.

Try it if you want but we'll have no way to know what it's doing.

Bryan

Here's another question you guys may have some advice on:
In this 11x11 room once I get it treated properly with the bass traps, where in the room would you recommend I sit to play the acoustic guitar to get the best recorded sound?
I normally sit with my back to one corner about 2 feet from that corner so the sound of the guitar can have a little room before reflecting. I also use omni mics pretty close to the guitar. I use the omni's because I can put them close to the guitar without getting proximity effect and also when they are close to the guitar it still limits the room sound somewhat even though they are omni mics.
Any input??

Just don't sit in the center of any dimension and you should be fine.

That's an interesting statement. People recommend symmetry as a matter of routine for side to side positioning.

If you're going to sit off center from front to back, then why not sit off center from side to side?

Jon

It's a tradeoff. Actually, you can sit 6" or so off center left to right and not cause any severe issues - in fact, many times that's enough to get you out of the nulls.

Shifting your whole setup 6" one way won't kill you.

That's such a small change to symmetry in comparison to something like treating the front left corner floor to ceiling and NOT doing the front right because there's a door there - make sense?

FOr mixing, yes, symmetry is impostant becuase of the whole left/right thing, but in tracking you don't have that, so why not get out of those big central nodes/antinodes?

SHould I consider putting spacers behind the mid/high absorbers on the parallel walls to make them absorb a little more bass??

Definitely.

About how far should the spacers keep the mid/high absorbers away from the wall? 1 inch? 2 inch?

Generally, for mid/high absorbtion on the wall, you'll get the best bennie for space given up by using spacing equal to the thickness of the panel. If you have a 1" panel, space it 1" from the wall. 2" - 2" off the wall.

You can do more but you'll get diminishing returns. Note, this is for on-wall panels and mid/high only.

While we're on the topic of small room treatment for vocal recording. For the corners, do you recommend trapping lower, or high near the ceiling?

Go low and high if you can, but if you only have so many and you're treating a small vocal booth, I woudl place them at mouth height to help with the high frequency reflections.

I'm doing the entire verticle corner in three corners and about 75% of the other corner because there is a vent at the top of that corner. I am then placing one 2'x4' trap horizontally in each lateral corner. I'm hoping this will really balance the bass in this small room.

Should I wrap each panel in a light plastic to keep dust from the panels from getting out? I am using the FSK on the front of the panels and wrapping them in landscape fabric. Will this be enough to seal in the fibers or should I also wrap in plastic painters drop cloth?

I am building my bas traps and I bought this landscape fabric to wrap them in but this fabric is pretty junky looking. It is more like a fabric/paper material. Is all landscape fabric like this??
I may look at getting burlap or muslin at joann fabrics. I have completed two 8' tall corner bass traps wrapped in this landscape fabric. If I go and get some muslin or burlap and just wrap it around these panels that are already wrapped in the cheapo landscape fabric will that be OK? Or should I remove the cheapo landscape fabric first?? Will this affect the sound if I don't??

I prefer muslin. It does a better job of minimizing color variation in showing through and is nicer to work with IMO.

Bryan

WHat about canvas?? Is it as good as muslin?
I found canvas "trigger" at joann fabrics at a good price but I'm not sure what canvas trigger is compared to canvas.
Any ideas??

Sry - answered in different thread.

Not familiar with canvas trigger. Most canvas I've seen would be unacceptable.

I'd stick with a known. Lightweight muslin to me is an excellent combination of being relatively transparent, holding in the fibers, and being inexpensive.

Bryan

Thanks for your help, AGAIN!
I bought a bunch of muslin at Joann's yesterday. Had I known I was going to use it last friday I could have gotten it for $.77 per yard. I paid $.99 per yard. I'm going to hopefully finish all my traps today.

Is it going to matter that I can only put one 2x4' panel in one of the vertical corners? I have a vent on the wall near the top of that corner. This corner is where I normally sit with my back towards this corner to record my acoustic guitars.

Also, strangely enough, the corner across the room where I normally face when I record my guitar still seems to have more bass issues. I have an 8 ft trap in that corner which goes from floor to ceiling and a 2x4' trap in the wall/ceiling corner beside this trap on one side and I can still hear more bass frequencies when I face this corner and play my guitar. I am about 10 ft. away from this corner also when I play my guitar. Any solutions??
I'm not done treating this room yet but I have 3 corners treated completely from ceiling to floor and the other corner treated with one 4 ft. panel.
If I put one 2" mid/high absorber near this corner bass trap and space it about 2" off the wall will this make a big difference in getting rid of the excessive low end??

Do you know exactly what frequency you are having trouble with? Maybe getting that information will tell you what kind of treatment you need.
So you are in one corner, and you hear LF problems from the opposing corner? Square rooms are hard to deal with.
How high is the ceiling?

Are you sure it's not just because you're actually hearing the reall bass from that corner since the cancelling reflections are now gone?

ahh, I had that reaction for a couple days after treatment too. But after measuring and some more recording, I am starting realize the low end is so much more detailed, that it almost sounds odd. As though the resonance I was wanting is now
actually "there" and seems to be too much? hmm, is that possible? i've had some treatment up for yeasrs, so I suppuse my ears have gotten accustomed that "I handle the truth" LOL

T

Well, go grab REW (Room EQ Wizard) and take some measurements and see what the frequency response and decay times look like. It's a freebie program. Runs under Java.

Bryan

Here is another thing I noticed: Like I said earlier, I have my back in one corner and I'm facing the corner across the room but when I turn a little and face the regular flat wall across the room to my right, I don't hear the excess bass anymore. If I start strumming a chord and face the flat wall to my right it sounds pretty good but as I turn towards the corner across the room I can hear the bass more.
The ceiling is only 8' tall.
I'm wondering if It will help if I put a mid/high panel up close to the corner bass trap and space it a couple of inches off the wall. Will a mid/high absorber that's only 2" still absorb a lot of low end if it is spaced off the wall?
When I was recording acoustic guitar and had the Foam By Mail foam up I could hear that same problem in that corner and it seemed to be a frequency below 200 Hz. if I remember. Sometimes there would be two problem areas in the low end and no matter what I did I could not eq them out. Of course when I was using the Foam By Mail I had overtreated the room and I was absorbing way too much mids and highs so my sound was totally out of wack anyway. Maybe when I get all of the traps up and the mid/high absorbers up and space them off the wall so there's some air behind them it will help a lot.

OK, I treated my studio with adequate bass traps with FSK facing covered in muslin fabric.

My room sounds much better but I have flutter echo. I have only used 3 mid high absorbers.
How many more should I make? I don't want the room totally dead. Just balanced for acoustic guitar recording. Will 3-4 more broadband absorbers be enough?
Should I just have not used FSK on my corner traps? If I had done that I'd probably still have problems with flutter echo from parallel walls, wouldn't I??

> I have flutter echo. I have only used 3 mid high absorbers. How many more should I make? <

Some things just have to be done by ear - or RT60 measuring.

> Should I just have not used FSK on my corner traps? If I had done that I'd probably still have problems with flutter echo from parallel walls, wouldn't I?? <

Yes, probably. So add some more mid/high panels.

If I make them from 4" #8 mineral wool panels that should help tame the bass even more, right?