Room Noise

[Bob1131]

Originally Posted by CrankyChris

It's definitely a problem. I try to use cardioid and supercardioid microphones - and close micing techniques. Point the mic away from the noise source. Put your computer in another room/closet.

Ditto!! It is impossible to get quiet time in my house, so I have to depend on close mic'ing with supercardioid mics and noise gates to minimize noise, and even then the occasional dog bark, parrot squawk, HVAC cycle or raised voice will slip in. Unfortunately, I am so accustom to those noises I don't notice them until someone else detects them in the recording and brings them to my attention.

[Jeremy]

The only place I can record at home is in my living room. To keep the noise down I remove all the noise producing items I can, close mic, and record late at night when I'm least likely to by disturbed by activity outside.

[ukejon]

I'm finishing up two 4' x 4' bass traps (4" deep with OC 703 inside), and three more 4' x 2' bass traps will arrive any day now. On this image of my "studio" (upstairs bedroom in a 110 year old house), the three blocks at the top are doors--entrance on the left, closet in the middle, short hall leading to bath on the right. The longer blocks on the bottom and one side are side-by-side sash windows. In general, the room doesn't not have too much reverb or echo, perhaps in part due to the textured plaster walls. I will be sitting roughly in the area of the square block, lower left. So where do I put the five traps?



I will probably do a version of Chris/Fran's isolation of the mic, to sort of create a smaller quiet zone or room within the room. This seems to make more sense then spreading them all around the whole space, because half of the room really is not being physically used. Does that make sense?

[ukejon]

I'm finishing up two 4' x 4' bass traps (4" deep with OC 703 inside), and three more 4' x 2' bass traps will arrive any day now. On this image of my "studio" (upstairs bedroom in a 110 year old house), the three blocks at the top are doors--entrance on the left, closet in the middle, short hall leading to bath on the right. The longer blocks on the bottom and one side are side-by-side sash windows. In general, the room doesn't not have too much reverb or echo, perhaps in part due to the textured plaster walls. In other words, it is not very reflective. I will be sitting roughly in the area of the square block facing the window wall to the east on this image. So where do I put the five traps? My chair is pretty low, so the instrument will be centered on any floor standing traps, which in turn makes me wonder about the height of any wall mounted traps. Do they stay relatively low as well?



I like Fran's concept of mic isolation with several of the traps, which seems really important in my space. I'm thinking about the upper wall between the doors and behind my head for the 4 x 4 traps, and then wrapping the mic with two or three of the smaller ones. But this is purely my own speculation. Is the ceiling essential, and if so can a 4 x 2 suffice above my head or do I need more coverage? There also is a Primacoustic Voxguard that could help isolate a mic, my computer, or be put somewhere strategically in a corner I guess. Since I will only be doing solo instrumentals, do I basically secure the exterior walls with the larger traps and then isolate with the smaller ones or should I use all five to create a sort of isolated space within that half of the room?

Many thanks in advance.....

[rick-slo]

Four inches deep it not really a "bass" trap although it certainly helps. I use a number of four inch deep and two inch deep panels (two inch mainly on the ceiling).

You get more bang per panel when they are near the corners of the room (placed near the floor or up near the ceiling).

I also put panels on the ceiling itself.

I have a few more panels on one end of the room - sort of creating a liver and deader end of the room.

[moon]

Actually bass might not be a problem, certainly not when you're tracking ukes. However, if you build up multi-track recordings with basses and other low-end instruments, you'd need to do something about it so you can monitor clearly.

The bass trap designs I've seen all have an air gap behind an acoustic slab. The depth of the gap tunes them to a specific bass frequency, so one of the best things to do might be to place the panels across a wall-wall or wall-ceiling edge, or better still mount in one of the corners of the room. The depth behind the panel will vary, which should make them absorb a range of bass frequencies. One thing I'm not sure about is if a bass trap has to have an airtight seal. I suspect all that bass energy just wafts out the open ends if you don't.

Anyway, 4" of 703 will absorb just about everything except the low bass end so these are great broadband absorbers. you basically need to break up every flat surface in the room, especially where they point straight at another flat surface. Typically, most rooms are rectangular, of course. I'd scatter a couple of dozen or more panels about on the walls and ceiling (this will become a great room for listening to music as well as recording )

With just five panels, I'd maybe try making a dead(-ish) corner with one placed across the walls and two either side.

Another thing I've been meaning to experiment with is making a little mineral wool "hat" for the mic, open only to the front.

What's the 703 like to work with? I've got a pile of Knauf Earthwool RS60 waiting to be turned into gobos (as soon as I figure out a good covering fabric) and the fine fibres can be really itchy if they get on your skin.

[KevWind]

Originally Posted by ukejon

so the instrument will be centered on any floor standing traps, which in turn makes me wonder about the height of any wall mounted traps. Do they stay relatively low as well?
Many thanks in advance.....

For a recording space there are some general ruls of thumb.

If all possible the playing and especially the mix position should be in a symmetrical relationship to what would be the side walls of the room. In other words centered between the left and right walls in your image. Currently your proposed sitting position is already problematic because asymmetrical reflected wave problems are more difficult to deal with than symmetrical reflected waves. You can certainly address some of this with free standing panels but symmetrical is easer.

Also the corner seams and wall line seams (i.e. wall/ floor and wall/ ceiling seams) are where the base is going to create the most problems thus as Rick said, that is where any bass trapping will be most effective.
For example you can place 4 inch traps diagonally across the corner seems with sides touching the adjacent walls, ( see photo below) this gives you the effect of dampening the base waves on the way into the corner and on the way back out of the corners. (double dampening)

This is the placement suggested by Glen At GIK.

[ukejon]

With just five panels, I'd maybe try making a dead(-ish) corner with one placed across the walls and two either side.

The one (southwest) corner in my room probably would be the place to tuck into. Could angle either a 4' x 2' or 4' x 4' panel across the corner, which begs the question about which would be more acoustically beneficial (I'm guessing the narrower panel). Again, my goal is to create a better recording space for my mics. Mixing and, consequently, monitoring really isn't an issue right now because of my emphasis on solo instrumental recordings.

As for the 703, it is like most of that stuff--potentially itchy and irritating. Gloves are essential but not too many of the fibers are floating about.

[Doug Young]

Yeah, 703 is pretty nasty stuff to work with. Some of my panels use Acoustic cotten, which appears to be recycled blue jeans :-) *much* nicer to work with, but most of my room is 703. I felt like I had that stuff in my lungs for months after I built my room, and I wore masks and gloves.

With only 5 panels, you're not going to really treat the whole room, and as you say, you're not trying for a mix setup. I'd probably use them like a gobo, as Fran does in his video. Maybe hang one overhead. Put three in front of you, to sort of create a wrap-around - like a large version of your Primacoustic - and simialr to Fran's setup, and then maybe one behind you. Basically build a little room for yourself. You can just experiment. If it's too dead, leave some space between them, open it up a little. If it's too lively, pull them in closer.

You might also try using some of this stuff to isolate your computer, if that's where the noise is coming from, tho for me, the only real solution was to move it into another room.

[ukejon]

Will do. By the way, have you all ever seen the method of keeping your laptop fan from going on during recording by putting the computer over top of a shallow pan with ice cubes in it! "I'll have my MacBook on the rocks, please...."

[rick-slo]

I used pre-made mineral wool panels from ATS Acoustics. IMO well worth it and they came with wall mounting brackets. The mineral wool is not a irritating to your skin and lungs as fiberglass. After I installed the panels I ran an air filtering machine in the room for about a month.

[alohachris]

Aloha Ukejon,

Wow, you get right into that DIY room treatment, dontcha, Uke? That's Great.

Because I cannot permanently alter my recording room, & all the surrounding glass (three sides surrounded by huge windows & doors out to decks), I approached DIY Room Treatment with three main areas of reflection (easily revealed by using a borrowed SPL meter) that I wanted to address:

- my tracking area where I sit & play & mic my instruments,
- my mixing area with the magic boxes behind & around the desk, &
- the acoustics of the room itself

That's why I built 22 4"x2'x4' OC 703 regular & 705FRK broadband absorber portable, free-standing gobos -for the flexibility of taming reflections everywhere they are & where I need to place them. That's why I often say that I create "room's within a room" & treat accordingly.

I also like to sing/record while standing up for better control, breathing & dynamics. So I build a vocal booth around me from floor to ceiling with absorbers - a slightly different configuration of absorbers from sitting & playing instruments tracking area. Kind of triangular in shape.

I use panels in my tracking area (in the best acoustic central part of the room - not near a corner or wall up here) by surrounding myself with gobos on all sides, in front & in back of me. And I hang a couple from the open rafters directly over where I play. So it creates a treated "room within a room" for playing/tracking.

Around my desk, I put gobos behind & above my monitors, a couple just off to the side of where I sit, & a couple more above me, using the FRK facing the room. Not all are 4" thick here. This really helps me with eliminating any mush or unclear frequency issues where I mix. I also pay attention to the rear wall of the room, often configuring gobos NOT IN PARALELL to the front wall. That reflection area is critical to tame, Ukejon.

In the large 30 x 40 room itself, I put 4"x2'x4' 703/705FRK combo panels across each corner (FRK facing into the room), from floor to ceiling with air in the corner behind each bass trap. I also have panels standing about 4" off the walls (not parallel behind my mixing desk) & a few above that area where some weird reflections were found in the room.

That's why I made 22 gobos, Ukejon. You can never have enough.

Some I use for all three approaches to room treatment. Very Easy to move around. And. I use fewer panels if I want more room revealed. Or add more space between the panels in my tracking area. I have nice maple floors, no rugs.

Builidng Broadband Absorbers:
I do all my work in building the absorbers outside (lucky we live Hawaii). If I make more than 3 panels at a time, I definitely will feel the 703 in my lungs for a day or so & the spray glue as well. I use a high quality mask when spraying glue. Gloves ARE a must & long sleeves are preferred.

The 703 can feel fragile at first, easily breaking off or crumbling in areas - not as rigid as you'd imagine 'rigid fiberglass' to be. Then you learn how to mold it, like on the corners to work with it & cover it more easily & what not to touch. I built a small table w/ legs that allows me to work on the panels from every angle without impedance out on my deck.

The trick to nice clean corners with the material is cutting & neatly folding the fabric in the corners & using hot melt glue. I also use that in the main fabric glue joint across the back of the panel. Get the HD gun & 1-2 bag's of glue sticks - $10-12 @ Walmart. You can't use sprayed glue on the corners, it won't hold as well. Use that on the panels edges & ends & for gluing the fabric on to the back of each panel.

I used white burlap to cover all of my absorbers, which keeps the fibers from moving around in my space. And I use decorative colorful porous fabrics (from the cheapest at Walmart) in a few areas of each absorber to spruce up the room & hide the center joints. Not perfect looking, but they do work perfectly & don't look too bad. The white burlap looks better than regular tan burlap to me. It all depends on how much you want to spend. Better acoustic fabrics are available, especially from that company in Maine.

I store the gobos when I'm not using them away from my main living areas to keep the fiberglass particulates away from me. Works well.

I find that ironing the material before & after you put it on the 703 keeps it flatter.

I also hang layers of mover's blankets in double layers in front of all the windows to help tame those ugly mids. A local moving company gives me all the used blankets I need, so many that I can color-coordinate them. I wash 'em, hammer in grommets & hang from Bamboo Poles ( I have so much bamboo up here you wouldn't believe it) that are then hung above the windows.

I'll go a week or two without recording. It takes me about 5-10 minutes to bring in the panels & blankets & place 'em where I need them. Or fewer if I'm only tracking. The rest of the time they are stored in a hall undercover in another part of the house. That way, I can have a lady over or guests or a music party up here, & the treatment doesn't get in the way. It did take some months to figure it all out. But it works for me well without altering the house in any way, Ukejon. Can't thank Fran enough for his video & advance work.

So that is the way & reasons why I "did" DIY room treatment with considerable help from Fran Guidry, Ethan Winer, Sound on Sound magazine, & lots of time over at the gearslutz studio treatment site. And of course, learning from all you fine folks here at AGF.

Good luck in your journey, Ukejon. Be patient, your setup will work itself out in terms of what your room needs & how to treat it & the logistics of fitting it all into a 100-year-old house.

A Hui Hou!

alohachris

PS: I hide the fans from my computer & external harddrives in a box I made from Homasote - Soundboard 440. I used a 1/2" 4x8 panel - only costs $34.00 here. Some people use that successfully around generators it works so well. Just a thought.-alohachris-

[ukejon]

Wow, Chris, that is quite the setup. I'm covering my traps with black speaker cloth, which I'm hoping is fine enough to hold the fibers in place. Maybe I should double layer? I've done furniture upholstery work, so this is pretty straightforward. I notice online that some folks leave an inch of space, sort of an air pocket, at the back of the trap. I presume that is similar to hanging the panel a bit off the wall.

Traded in my Blue Baby Bottle for a Sennheiser MK4, which has better rear rejection. Even so, doing a side by side listening test reveals that it picks up more ambient room noise (I still think it is the furnace and radiator system in this house) than the SDC mics. I'll do some more tests. Interestingly, the Shure SM57, while not nearly as tonally precise, sounds much quieter even with the gain cranked up. Not that I'll use the mic but it is rather flat and clean sounding.

Have folks here ever used a homemade mic isolation box? There are some DIY versions online. In theory, what would be the best design--hard shell, soft shell, dense foam, ridged foam, parallel or non-parallel sides? Obviously you don't want a "boxy" sound, which can be an issue with close micing using these things.

[alohachris]

Aloha Ukejon,

My favorite mic for recording ukulele is a single Mojave MA-200 tube LDC. Can fnd 'em used now for around $700.

It captures the full ukulele sound & warms it up considerably. That's also my primary vocal mic, even though I own a pair of vintage U87's.

Check that mic out sometime.

http://mojaveaudio.com/videointerviews.html

alohachris

[CrankyChris]

Traps have helped me quite a bit.

I built 6, 4.5 inch deep (2ft X 4tf) bass traps and 6, 3 inch deep traps with 703 or maybe it was rock wool - don't remember - but it's essentially the same thing. Obviously they don't help with Rufus growling at the neighbors cat, but they do get rid of (what is almost always) nasty small room reverberations (standing waves). I put the bass traps in the corners and generally spaced around the room and then I tried to create an area in my room where there is max absorption. Above me - to the sides...The pretty much suck everything out - so much so, it's almost disturbing to play b/c you can't hear any wall reflections...at all. Great for getting good recorded signals - but disconcerting when practicing. I go in the other room (I'm much better in there