Preparing Spare Room for Acoustics

Sirraf

Member
I have 2 spare rooms in the house that are not being used. One is where I have my kit currently. The room is about 13'x16' shag carpeted. Walls are bland so I am gonna throw some nice dark blue paint on it. I have one single window that I am planning on putting some sound dampening curtains on.

So the plan right now is to use some thin pegboard and buy some foam acoustic squares and spray adhesive on the pegboard, stick on the squares, and hang the pegboard. I am looking to do a (2) 8'x4', (2) 4'x4' sections on the walls. I will eventually get some corner bass traps to help as well.

Anybody have any other tips that well help with the sound quality of the room? What else can help give it a good jamming atmosphere?
 
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Ghostnote

Guest
I'm in the process of building a room-in-a-room jam space in my garage. For now it'll just be drywall, but when I can afford to do it, I'm going to put tongue and groove pine on all 4 walls and the ceiling then put widely spaced 1x4's and 1x6's on top of that. I'm waiting to see how that sounds before I commit to either carpet to deaden the room or wood flooring to keep it more lively. I imagine I will need some bass traps or Hemoltz traps in the corners too when it's all said and done. We'll see....
 

KamaK

Platinum Member
Anybody have any other tips that well help with the sound quality of the room? What else can help give it a good jamming atmosphere?
For me, the objectives are:

1: Get rid of flat surfaces
2: Get rid of anything that resonates sympathetically

Hanging up wall to wall drapes will do 90% of the job that wall to wall egg board can do, is cheaper, easier to install/remove/etc.

Set up a high quality power strip at each station. Make sure your outlets are grounded correctly and phase coherent.

Grab decent LED lighting. Never use CFL or tube FL or anything with a transformer that can buzz/hum, or cause guitar to buzz/hum.

Grab a white board panel and a pack of expo pens.

Put your AC/Beer fridge/fan on a power strip to make it easy to turn them all off when you're recording.
 
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mikel

Platinum Member
I am thinking of doing a similar thing with a spare room I have. My intention is to underlay and industrial carpet the floor and paint all the hard surfaces. I shall add another double glazed window inside the existing, and an extra sealed door to aid sound insulation.

I plan to have wall drapes that I can open or close depending on how "Live" I want the room to be. I like to record some stuff and its handy to have a tuneable room rather than using effects all the time.
 

konaboy

Pioneer Member
So I haven't seen anyone ask if you are concerned about sound getting out of the room to the rest of the house or neighbors?

I'd say you are headed in the right direction for interior treatment, may take some experimenting with where to place the panels to find out where they make the room sound best. The other thing is placement of the kit in the room, different areas of the room can make the kit sound fuller or more choked. Where are you planning to put the panels, in front of the kit, behind the kit on the side walls?
 

dboomer

Senior Member
Are you talking about treating for the sound within the room or to prevent sound from getting out?

The dimensions of a room will have the final say about the low frequencies within the room. Hanging drapes or foam tilde will suck out the mids and highs (leaving the lows to build up). But the real problem will be the low bass. The physical dimensions (assuming an 8' ceiling will have some big holes at 43, 56 and 70 Hz (right in the middle of the kick drum) due to room modes. You'll need to add bass traps to try to tame those holes.
 

Morrisman

Platinum Member
A bookshelf full of books and a soft lounge chair or two will control/disperse some sound. Depends if you have room though.
 

mikel

Platinum Member
Are you talking about treating for the sound within the room or to prevent sound from getting out?

The dimensions of a room will have the final say about the low frequencies within the room. Hanging drapes or foam tilde will suck out the mids and highs (leaving the lows to build up). But the real problem will be the low bass. The physical dimensions (assuming an 8' ceiling will have some big holes at 43, 56 and 70 Hz (right in the middle of the kick drum) due to room modes. You'll need to add bass traps to try to tame those holes.



How do you tame a hole? Do you mean there will be peaks in those frequencies that need attenuating? Not a pop but real questions as I am going to do something similar myself.
 

Morrisman

Platinum Member
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How do you tame a hole? Do you mean there will be peaks in those frequencies that need attenuating? Not a pop but real questions as I am going to do something similar myself.
The hole is caused by a wave reflecting back on itself, the same cause as peaks. You tame a hole by reducing the reflection at that frequency. Problem is, 2 inch foam only reduces frequencies down to 200Hz or so. So you need something thicker, like a corner trap, which can be up to 12" thick.
 

xsarith

Senior Member
Hey, it's been a while since i've been on this site but acoustics is something I know about so I'll chime in.

Since you said jamming I'm going to assume that this will be used a practice room for both you and your friends only and not as a studio which would be treated in a different (more adherent to Live end/Dead end theory).

Firstly you not all acoustics are bad, it actually comes down to a more personal preference, granted there are certain aspects that remain pretty universal such as lowering the impact of nodes and anti-nodes, but things like reverberation, early refection properties (delay/echo) are included in a rooms acoustic nature. some people like very lively and others like complete anechoic chamber like deadness, its a preference. Again I'm talking a room for jamming, this all changes for a studio.

So a brief lesson in acoustics. As I'm sure many are already aware sound uses a medium to travel and travels in waves, these waves cycle and give birth which we measure their cycles per second (frequency) in Hertz. A wave that cycles 100 times per-second is 100Hz, for example.

Note that one cycle of a wave is when the wave goes from any given point, to its complete inverted (rarefied) state and back to its original (compressed) state. It doesn't matter at which point you measure from as the result will always be the same, typically we measure from the point of no displacement on the wave just for ease.

This means that waves have a wave length a physical measurement of how long one cycle is in distance. Low waves, such as that below 100Hz have long waves, meters in length, while high waves, 15kHz+ have just millimeters. This happens exponentially, the difference in length between 100Hz and 110Hz is smaller than that of 110Hz compared to 120Hz.

Another note, Compression and rarefaction are the two states of a wave form, often referred to positive and negative. Both produce a sound, it is only when there is no displacement in the air that sound doesn't exist.

Next on to standing waves. A standing wave is when a sound wave is reflected of a surface at complete opposite polarity. This means that the compressed and rarefied movement become inverted but now occupy the same space as the original wave at the same time. This creates Constructive and Destructive interference, some frequencies within the wave get boosted (increase in volume) and others get cut (reduced in volume). These points are called nodes, points of no displacement and anti-nodes, points of maximum displacement, the more displacement, the more amplitude of a frequency. Nodes can be characterised as spots within a room that are like balls in 3d space where the sound differs. Typically the centre of room is always going to be an nodal point unless it is broken up and absorbed.

The goal with most acoustics is to reduce the amount of standing waves within the room, remove flutter echo and lessen any reverb.

I'll start with removing standing waves as this is the majority. There are 2 ways to collapse waves, diffusion and absorption. Absorption is the most common and understood way, this is using material to absorb energy contained in sound waves, typically using acoustic foam which is not like normal foam as it is far more dense but just as porous. Density is a major factor in absorptions as the more dense something is the affect in lessening the energy the resistance will have, however this is where the material used comes into play. Material that is fibrous or porous is used as it has a much larger surface area and generates more frictions and therefor doesn't reflect as well as solid smooth objects. This is how brick and foam differ, brick is far more affective absorbing sound however as it is fairly smooth it reflects the sound inside the room back into it while foam will disperse it, but as someone has pointed out foam will typically only take care of the higher frequencies.

So to just go on to your curtains. Putting thick, heavy curtains over the window will absorb some higher frequencies, however it does a lot less than most make it out, its dense, but also thin and typically tightly woven, meaning not all that much friction overall when compared to other materials. If you use them, try and use ones that are woven and feel rough. Or just ignore them and forgo curtains, I recommend this a bit more than curtains. Just having a bare window will do more for your acoustics in terms of frequency break up, this is because (I assume) your window is made of glass and the wall opposite is not, that and that it is also inset from the wall its attached to. This means that the standing waves where that window is will differ from those where there is a wall and ultimately collapse for them frequencies.

The latter solution is what is called diffusion. Making a surface uneven, using different materials, putting up shelves, etc is a form of diffusion, this is while acoustic form comes in various shapes rather than just flat panels, to diffuse the sound that hits it.

So to put it simple terms, using foam as well as other thick dense fibrous material will dry out the room, lessening the reflections and the absorbing higher frequencies. Diffusion will reflect the sound but break up the formation of standing waves evening out the notes and anti-nodes for frequencies in the room. To treat a room effectively a smart use of the two is needed.

Use diffusion to even out a room by breaking up the texture between two parallel surfaces where a noticeable standing wave has formed. You can actually use the rooms dimensions and measurements to work out where they will form and which frequencies they affect, theres and online calculator that does this for you. Then use foam to control reverberation and higher frequencies, as well and remove flutter echo.

I haven't mentioned flutter echo yet but its concept is simple, a flutter echo is a noticeably loud early reflections of higher frequencies, just google this and theres tones of audio examples. Early reflections are commonly charaterised as delay (thats repetitive), while reverberation is a mass of reflections that are so close together you cannot perceive each individual reflection. The progress of sound has 3 stages, the initial sound, the early reflections, then reverb.

So really how you treat your room comes down to how you want it, if you want a lively room while taming unruly frequencies use more diffusion that absorption, if you want a dead room with little reverb then use more absorption and minimal diffusion.

Theres a few other points about acoustic that would apply but its starting to get into the far more detailed physics side, which while I love discussing, is far more than I can explain in a single forum post without visual aid. One day I may write an acoustic manual or something haha.

If anything confused you or you want clarification then just ask.
 

running

Member
Couple of questions: how high are the ceilings, do you want to track in the space or just jam, and what is your budget for treatment?
 

Morrisman

Platinum Member
A simple rule of thumb for natural sounding rooms is to avoid pairs of smooth surfaces. Eg if the ceiling is smooth, the floor should be carpeted. If one end wall is smooth, the opposite end wall should be treated, etc. This leaves some liveliness in the room, but removes flutter echoes.

After that, if there are dead spots and boomy spots for certain bass notes, add a corner trap or two - triangular wedges of foam which stack up in a corner.

Finally, experiment to find the best place for the kit within the room. Most likely it will be in front of a 'dead' wall.
 

Sirraf

Member
Thanks for the replies everyone.

I have bought some acoustic foam 48''x24''x2.5''. I bought 4 panels of it along with (4) 12^ bass traps. About 100 bucks worth of foam material. I think this will help with a little echo I have and help with overall sound quality.
 
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The SunDog

Guest
Don't over do the sound treatment. Plaster and wood walls give a really nice, natural room reverb. Over deadening is a real tone killer. Set up so that your back is to the long wall and take advantage of the rooms natural ambience. Only use treatment if the room is overly reflective and then use just enough to knock down the reflections without overly killing the reverb.
 
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