|02-21-2012, 10:57 PM||#1|
The Room Tuning Thread
AKA, I got monitors, now wut do? AKA, Make your room suck less.
This is a starter guide to treating a typical home recording setup. Its probably pretty bloody long for something that claims to be a 'starter' guide, but acoustics is a huge subject, and it will be just an introduction. I'm going to keep things as realistic and practical as possible. You can, if you so desire, spend unholy fuckloads of money on acoustics and room treatment, and you can put in a lot of effort and get minimal improvement, or make things worse if you go about it the wrong way. If you think this is long, you can get a degree in acoustical engineering too But I am a n00b at this in the grand scheme of things, cant afford a purpose build space and Bob Hodas to tune it, and the ghetto ethos of this guide will reflect that. I dont expect my situation is that much different than most here, so hopefully what I can tell you can be of use. If a serious acoustician stumbles by, please, tell me all the ways in which I am wrong, I would seriously love to know.
I'm going to put what I know and what I think I know about tuning your room in this guide. I was a physicist once upon a time, so I'm approaching it from a lay/pseudo-technical 'this is what sound does in an enclosed space, why its bad for reliable monitoring and what you can do about it' sort of way. I'm going to suppliment it with some youtube vids that you should probably just watch instead. I am not an expert on this subject by any means, and also invite anyone that can to provide any addition information, error check, and generally improve on all the stuff I'm about to type to do so.
Accurate monitoring can be divided into three objective parameters, one pretty easy and two a bit woolier, but still objectively better or worse, and not a matter of opinion in the least: linearity, transient response and accuracy of stereo field. Pretty much everything I say in this guide is to make these three things better, but linearity will be the major theme, followed by stereo field, with transient related things kinda taken care of in the process. Apparent depth might also be included as a fourth thing, but we're getting into handwaving subjective territory there.
What you can hope to get from this
You must know your monitoring. You maybe think you already do since you've heard music on it, but I mean, mainly, know its spectral response in your listening position. A big part of why you need to know it is its almost certainly not going to be perfect. A hopefully realistic goal from carefully seting up your monitoring is to have a reasonably accurate stereo field, clean, crisp transient representation and all frequencies between about 50-60 and 16-18k (assuming your hearing can get up there as well) clearly audible, meaning there are no nulls so deep that surrounding frequencies mask that range/band. If you want it, and manage to get it, then fair play to you, but “Linear” with a capital L is not a realistic expectation for most home monitoring setups. Correspondingly its as important as anything else that you know your monitoring like the top of your cock. I hope you can read this guide, watch the vids with the real experts in them, do your own research, and configure your monitoring so that its much better than it was before, but the last stage of all this is still really “Know whats still wrong with your monitoring”, and mix accordingly. The realisic expectation is that you end up with a decent listening position that you know well enough to use effectively. (As opposed to a near-linear entire room, which is a whole other story)
Right, on with it.
Most of us are recording in what amounts to pretty small rectangular spaces with hard parallel walls, standard issue 2.4m ceiling and a window and door or two. It sucks. Depending on overall dimensions, the ratios of the length/width/height, wall material/s and other stuff that may be in the room that has nowhere else to go small rooms in homes can be anywhere from 'workable' to 'nightmarish' acoustically.
First, your monitors. As long as they're alright, its not that important what they are. People often preoccupy themselves with the monitors, and think that an upgrade is going to automatically significantly upgrade the accuracy of their overall monitoring (btw, whenever I say 'monitoring' I mean everything that leads to the sound you ulitimately hear, and its fidelity and reliability, as affected by the monitors themselves, their placement, the room as a whole, the location of the listening position, all treatment). Monitors themselves are very important, but unless youre taking your first leap into decent monitors from absolute bottom end or PC/poor hifi speakers, I can pretty much gaurantee you the room is the biggest problem you have. Thinking about monitors without thinking about the room is like thinking about a pickup without thinking about the guitar its going in. And if the room is rubbish and the monitors and listening position carelessly placed, then its like the guitar has year old strings. 3 of them. If you try to put great monitors in a crap room you will be lucky to get any significant benefit. Otoh, even mediorcre monitors in a good room, where they have been well placed and the room appropriately treated, can sound great.
I'm going to do this in a few sections.
1. The problems of small room acoustics. You need to understand whats going on to deal with it. this will be divided into:
Low end problems. Low frequencies propagate omnidirectionally and excite room modes because the room dimensions often match low end musical wavelenths, and the problem and treatment reflects that.
High end problems. High is more directional, too high frequency to excite room modes and affects different things than low end problems, and can be treated differently.
2. Analysis. Going by general guides and qualitative information, like most of this guide, only goes so far. Your monitoring must be adapted for your room. The right treatment in the wrong place will do next to nothing, and a kind of treatment thats good for one thing will do fuck all to another. You need to have at least some rudimentary tools to analyse your exact room, and some knowledge on how to target your exact problems. At the very least, you need a way to really know for sure if the last tweak you made actually made a desirable difference (and didnt cause any new problems)
3. Monitor and listening positon placement. This is the most important thing, and the only real obstacle to refining it is time and logistics/space.
4. Treatment, ghetto version.
5. Eqing, lazy tagged on the end because its not that important version.
1. Acoustics Problems – Low end
In the simplest possible model, a room with no doors or windows and perfectly reflective walls and soffit mounted speakers, you will excite room modes at reasonably predictable frequencies and relative amplitudes. Low frequencies propogate out spherically from the monitors, hit and bouce off all the walls, floor and ceiling and air in the room resonates at specific frequencies (speed of sound/the wavelength, where the wavelength is the distance between the walls) as sound bouces between parallel walls, much like a guitar string. The least fortunate and by far hardest situation to treat is a room thats close to a cube, or more likely thats square from the top down, as the modes are in at the same frequencies (you can think of it as them being 'in tune' with each other). The next worst is where the dimensions are evenly divisible. The best is where walls arent parallel (though there will still be problems), and the most common 'good' scenario is where the dimensions arent evenly divisible, so the modes from each axis dont stack with each other (which you can think of as the modes being 'out of tune' with each other). Bigger is better, because larger rooms resonate at lower frequencies that are less likely to interfere significantly with music, but most small-ish rooms (and rooms the small side of big) have serious issues exactly where you dont want them to: between 50 and 200-300hz. Larger rooms are not immune, because though their fundamental modes are lower, they will have overtones at higher frequencies that still bugger things up. But if youre lucky enough to be in a 7 by 10m room you have less to worry about.
Corners are the worst places, since you have a meeting of 3 boundaries and the reflections from those boudaries all constructively interfere (add up and get louder). Wall:ceiling and wall:floor joins are second worst places, since there are 2 reflections to add round there. Any speaker placed in a corner will excite more room modes. All things being equal this is BAD. But it can be good/usefull in some circumstances. Tread extremely carefully putting speakers of any sort in corners.
You probably know all that already. Cool. You've been reading. Its good for you. The simple room modes between parallel walls model is a bit of a fantasy though; its just the start of it. The situation in real life isnt as simple. There are additional reflection paths between adjoining walls, floor-wall-ceiling reflections and so on as well, not just parallel. Also, the walls and floor resonate, but the speed of sound is higher in them, so the interaction of that resonance with the resonance of the air in the room creates phase cancellations. Then the monitors distance into the room/from the boundaries and your placement with respect to them means that what you hear is an extremely complex relationship between monitors, room and placement in the room. All sorts of frequency imbalance can set in (or be significantly reduced) at your listening position. There are almost always problems at different frequencies, and far more of them, than simply calculating wavelengths of room modes would lead you to believe, even in a simple rectangluar room with no other stuff in it. With careless monitor placement it generally just leads to a clusterfuck of terrifyingly non-linear low end response (I'll show you some later), but you can work with it, to an extent.
Time domain; modal ringing. You have modes and you have modal decay time. This is related to how well the room is damped and how closed off the room is (harder/denser walls with fewer doors and windows, no outlets for pressure in the room, have worse ringing problems, in addition to their likely worse frequency response problems). You excite a LF mode (that you presumably couldnt get rid of entirely), it takes a while for the energy in that resonance to disspate. This blurs low end, makes it mushier and looser, hides detail, kills tightness. Fortunately treated much the same way as diminishing the magnitude of the modes themselves, so we shant go into it too much on its own
Problems – High end
Hf is much more directional; you can imagine it reflecting around like light from the monitors. If there is a hard surface, hf bounces off it with angle of incidence = angle of reflection. This means that in the simplest possible case, with a room with the least stuff in it and monitors placed optimally with respect to the desk and a carpetted floor (which we will potentially foolishly assume is perfectly absorbant to hf, which is likely not true at all, but its easier to tell ourselves that because the floor is usually the only thing you can do nothing to improve), the hf information that reaches your ears takes 5 different paths per monitor. Direct, which is the only one you want, and reflections from left, right, up and the wall behind you. The more stuff you have kicking round, the more nearby surfaces, the worse it may be.
That means phase cancellation and comb filtering. The different paths are different distances, which means different travel times, which means phase differentials. Lots of them. Youre hearing the sound from at least 5 different sources, in effect, stacked on top of each other, per monitor (most of the time). They arent all equally weighted, of course, and you may have a wide or deep room that mitigates the effect of some of them, but they are all there. How important they are depends on your exact room.
There is also the issue of flutter echo, which is were a high frequency reflection between two surfaces stacks with itself to produce a distict tone, as the pulses bounce off each wall and across you repeatedly, you hear the sequence of pulses as a tone (since the pulses arrive at your ears with a given frequency, your ears intperpret each reflection as a wavefront of a more prolonged sound). Its most obvious in transients; its also why some acoustics guys that know just enough to be dangerous clap their hands in different rooms (well, thats a sensible thing to do if you know what youre listening for and understand that a clap is nothing more than a quick glance at a rooms response in that one place in the room, only in the frequencies made by a handclap, and nothing more). This is also very (arguably more) important when tracking in any room, especially with acoustic guitars, drums, and to a degree, but less so, vocals and teh br00talz guitars. It pertains to monitoring as well, but should really go in the rightly different topic of general 'live room treatment' which isnt rightly the same as what we're dealing with here. Its also usually fixed quite accidentally in the process of dealing with everything else in the ghetto pseudo-control room treatment we're dealing with here.
Know what youre dealing with. You should measure the spectral response of your listening position. Easily, readily available ways of doing this, in order of increasing effectiveness/decreased half-arsedness:
1. Tone generators + ears. Tone generators kick out waves (usually sine, but there are generally options for square etc) at a bunch of set frequencies. Often 1/3 octave. Rubbish. Tolerable for a quick check at best. If you pick up problems with this, you can be certain there are 10 more you cant hear for every one you can.
2. Tone generator + decibel meter. Better. Not terribly reliable, error prone (mostly human, variation in location of the meter, that sort of thing) but OK for a quick relative check of one frequency against another. Same issue with missing too much data out.
3. Tone sweep (CD or programmed/software/vst/MIDI) + ears. More detailed. More detailed is better. Pretty much qualitative/subjective. Pretty much qualitative/subjective is not better, its unreliable.
4. Tone sweep + decibel meter. Better. Detail + relative measurement = getting somewhere now. Doesnt store the info, though, cant compare different setups reliably, and still error-prone
5. Tone sweep + Linear Omni Mic + recording from linear omni mic in your listening position, look at amplitude variation through recording. Cooking on gas, in terms of the information you can get from it. Sucks in terms of ease of interpretation of the information and time it can take.
6. White Noise + Linear Omni Mic + Recording through mic in listening position + Frequency analyst applied to recording. Win. Do this. The only reason not to do this is you dont have a suitable mic (must be omni, should be linear, if not, make damned sure you know the mics response. For the love of god dont use a 57).
.....and a tonne of more expensive ways of doing it that are indeed better, but really for cost/benefit ratio the list ends at White Noise+Testmic+Spectral analysis. One or more of 1-5 may be used to suppliment this main method or have a quick listen to/check of a certain problem range, but they are all less effective than 6, and some are harder or more time consuming to pull off as well.
You are now armed to proceed. Do not skip this step. Measure your listening position, as it currently is, at the very least.
3. Placement of Monitors and listening position.
This is the single biggest improvment you can make, and the first thing you should do. Spend as long as you possibly can, move as much stuff around as you need to, try as many placements as possible, get your monitoring as good as you possibly can with placement of the monitors alone.
For the rest of this guide I want you to think of the monitors and the room as one thing. You arent really listening to your monitors, you arent really listening to your room, youre hearing their interaction at your listening position. You are trying to create the best interaction between them that you can to get the best monitoring you can. This is extremely important. It cant be overstated. Unless youre in a tent in a field, youre listening to the room-monitor interaction, not either one of them (the same goes for cabs/combos, btw, but thats another story).
I'm gonna tell you a story in pictures. A thousand words, etc. Typed enough of those already, and way more to come. Pictures of power spectra of different monitoring in the low end.
Number one. I'm going to call this 'Looks like I should get the crampons out and scale the bastard'
Number two. Its entitled 'Its alright, I only needed 40hz and lots of spikey crap anyway but at least the lowest lows look smoother, even if there is a huge hump'.
Number 3. This one goes by 'Not too bad, actually'
Number four , 'Where have you been all my mix'.
The point of this exercise is this: They are all spectra of my adam A7s and Sub 8, in my 2.4/2.9/4m room. The only differences are the placement of the monitors, and other stuff in the room and where I hear it from.
What I ended up with is not linear, but by christ how much better is it than what I started with?
Look at the scale on the Y (left, or up to you non-graph-reading types). These go from a range of ~30db to about 8 or 9, or +/- 15 to about +/-4. Most monitor manufacturers that bother to give an error rating give +/-3 as assurance that the monitors are pretty flat. Now, these tests were with an AT4050 in omni mode, so the mic scews them: I need to know how much. AT4050 in omni, on about the same frequency range as the spectra above.
And it actually looks a bit better now I can subtract that from it. Yay. I stiill have a hump centred on 150Hz, about 50-60hz wide and 3db peak, and that 70Hz peak means my dip into 100 is a bit lumpier than it looks in my analysis and I likely have more of a peak around maybe 80 than my graph shows, but these issues are not major enough to really distort hearing those regions or regions around them, so I can work with that now that I know its there. Win.
The rooms treated, but it was treated with the same stuff in all of the tests so thats not a factor in the differences you see. That it was treated does contradict some stuff I'm saying (like 'do monitor placement before anything else'), but hey, ITT, you learn from my mistakes. The differences are the wall they are against/axis they are firing down, distance from each other and the wall behind them, and final refinement moving them each just a few inches. Ask Blankplank how often I've moved things around: This is why. Ask anyone thats been in my studio how much I will strangle you with your own intestines if you touch my monitors: This is why.
Now, exactly what I moved and where to make those differences is completely irrelevent and of no use to you whatsoever. Thats my room, yours is different. The point is, it was moving stuff that made the differences. I cant tell you for sure 'put that there and that there'. I didnt even know for sure in my own room, that I can hear myself, I had to experiment, albeit in a semi-educated fashion, using what I know of acoustics to make each change one hopefully for the better. You'll have to experiment too, in your own space, armed with some understanding of what the fuck is going on.
So what the fuck is going on?
I mentioned earlier about low end response actually being a lot more complex than a simple modal model in 3 axis because there are other refection paths, and once the monitors are out into the room, all bets are off, and that you can use that to help you set up a good monitoring position. Its like this:
The room 'wants' to resonate at its basic modes, in the simplest way it can (which is still qutie complex, but much simpler than the reality you end up with). The monitors skew and distort that, continually driving what amounts to broadband noise into the room at two points within the room, which are out of phase with the room modes (not by a lot, youre dealing with pretty long wavelengths here). You are not listening at the exact location of the monitors though, youre listening a couple/few more feet into the room again. Its what happens there that you actually care about. Its a mistake to try and tune a room based on room geometry and monitor location: youre tuning the interaction of the monitors with the room for a desired net effect and at your listening position.
The result that you will tend to create a handfull of peaks and nulls in the response of the room in any given position as the rooms resonance interacts with the monitors broadband output, with the frequencies being heavily influenced by the phase differential between the monitors woofers and the reflections and resonance of the room in the place that youre sitting. What youre trying to do is place the monitors so that in your listening position when the rooms excitations are compressing, the monitors direct fire is rarefacting at the problem frequecies. And vice versa.
Its not a very easily predictable thing, especially in a real room with lots of stuff in it and getting the best out of it is trial and error, but thats pretty much whats going on.
Unfortunately its not the only thing you need to be mindfull of. You want a good stereo feild and phase coeherent mid and high end as well. That requires you, the extreme vast majority of the time, to be just inside an equilateral triangle formed from a point behind your head, and each monitor, and each monitor to be the same distance from each side wall. You dont want the firing lines of the monitors to cross over, though its not disasterous, it increases the phase cancellation you hear and can blur your stereo image. Dont cross the streams!
So choose a moderately sensible location for your desk, and therefore where you will sit. Thats generally a starting point. “Sensible” is quite often against or just out from a wall. Out is good if you have the space for it; youre trying to affect frequencies with long wavelengths, being a fair way into the room is generally optimal. 38% of the way in for your listening position is often quoted as a rule of thumb; this is because thats a relatively convenient odd fraction of the modal length of the room, placing you in a point where the rooms main lengthwise modes are theoretically nodal. The 38% rule is not a real rule. Its a guideline based on simplified theory. In reality you may get a better placement somewhere that doesnt make any mathematical sense to you. Thats fine, but all things being equal your listening position, and therefore if needs be your monitors being out into the room is better.
You should be central between side walls and are probably going to get the best results with the monitors firing down the longest axis of the room. Probably. Not always. But, Probably. Draw an equilataral triangle from just behind where your head would be right up to each wall (the wall is one side, obviously). Try the monitors at different points along those lines. Keep them each the same distance from the wall behind them, and each the same distance from the walls to their sides. When you have that as good as youre going to get it, start moving them in and out from the lines (so youre kind of placing them on in effect a smaller or larger triangle). Out is better than in (see 'dont cross the streams!') but move them closer together if you must. If no joy try moving the goalposts again and move the listening position further in or out in the room and start again. Remember: youre moving 3 main things: each monitor and where you sit; all three of those need to be carefully chosen.
You should be checking the response in your listening position with each change with actual analysis. If you end up happy with them, leave them there. If you cant get happy with them there, try another wall, same basic drill. If your room is symmetrical then dont panic; things like locations of windows and doors can have a big effect, so opposite walls in symmetrical rooms can actually lead to very different listening positions. Move, test, move, test, move, test, when happy or concinved it cant get any better, stop.
Thats most of the benefit you will make. If you do that and end up with a good listening position with that alone, pat yourself on the back and be extremely happy. But you probably didnt and it can probably still be better. That means...
Now, you have your analsys tools, you have your placement as good as its getting, and you should be hearing major improvments already. You can make some more with treatment. Bottom line in typical home environments is you can not ever have enough treatment. Literally, you cant fit the bloody stuff in there where you want it to go. The treatment really has to work in tandem with the placement. If you placed monitors and your listening position carelessly then treatment alone probably wont be able to make enough difference to get you to as good a listening position as you can. Likewise even if you meticulously placed your monitors and listening position, its almost certainly not enough and you will benefit from treatment. All this depends on the room, locations and the monitors (not better or worse per se but whether the particular monitors you have produce a balance that balances against your room: very hard thing to plan, almost entirely luck of the draw).
Really this is in treatment, but you probably should have done it already: stands. Good ones. Heavy stands, filled with sand and with spikes on the bottom (to decouple them from the floor). They are your friend. Or, alternatively, the exact opposite; lighter, freely resonating stands that are allowed to vibrate and so decouple the monitor from the ground. Both work. A major factor in cutting down room modes is isolatiing the monitors and reducing mechanical vibration transmission. Very heavy dedicated studio desks do this automatically to a degree. If you have your monitors on a simple table or PC desk, then it will also resonate, and that resonance skews what you hear. If at all possible, dont put your monitors on a normal table or desk, because of this resonance and because the desk will probably add a reflection path for high end and cause phase cancellation.
You can get a bit opportunistic/resourcefull with this. Results may, in fact, will vary. I promise nothing. Use your measurement stuff to see if youre really making improvments after any change. But, if you have furniture and what have you that you can positoin strategically that cant go anywhere else, do that. Couch jammed into in a corner = improv bass trap, bookshelf just off the wall = improv bass trap. Some people will try and tell you that its also a diffusor; bollocks, but its not a half bad trap placed right. Cupboard? Yes, it is. In the right place its also a bass trap. Cab? Bass trap. Bass amp? Bass trap.
Etc etc etc. Use what you got however you can, see what happens. Careful with this improvising bass traps from random crap. You might just make things worse. But it can make things better. Always check with analysis.
Making treatment. Low end and high end are different. High end is by far the easiest.
“Real” bass traps = money. Ergo ghetto basstraps = win.
To attenuate low end you have to consider four main things: mass, gas permeability, frequency, placement. Put the right sort of trapping in the wrong place and youre not gonna do much good. Put the wrong sort of treatment in the right place and you might even make things worse.
Really low frequencies need mass. Its not quite the only way to skin that cat, but its probably the best. We're talking 40-80hz or so and the highest density rock wool you can get, and quite a bit of it. Straddle corners with it, floor to ceiling and at least 3 inches thick, if you can. 120Kg/m^3 is as dense as I know rockwool to get and is what I used to get at problems round 40-80Hz. Maybe I got lucky, but that seems quite effective. If in doubt thicker is better, especially for lowest lows.
If you arent trying to hit frequencies as low as that (100-300 ish.....wut do with 80-100 I hear you cry? Judgment call, in all cases really; I'm just trying to choose frequency ranges where I'm at least pretty confident I can advise you of the right kind of thing to do) then you can use less dense material. Thicker is still better. The objective is the sound passes through it, and energy is taken out of it in the process. You can use relatively lighter absorption for higher frequencies (that will do next to nothing to lower frequencies). Trying to use anything really dense for higher frequencies can be unwise, since denser material is more likely to just reflect off higher frequencies, and so maybe make more problems. Beware in your placement of the densest and heaviest treatment youre using what you might be doing to mids and low mids. For ~100ish-200ish look at 30-60Kg/m^3. The semi-legendary Owens Corning 703 is round the top end of that range (50kg). I default to 60Kg generic rockwool.
Setup of bass traps in all cases is enhanced massively by an air gap. 7-10cm is generally about right, but it really depends what frequencies you want to hit and what material youre using. Bigger airgaps might intuitively seem better, since youre trying to hit low frequecies with long wavelengths but can actually be much less effective. When sound hits the trap, some of it will bounce off it, some will pass though, when it comes out the other side, it bouces off the wall and the same thing happens again; two stages of attenuation/aborption and a stage of using the reflection of the material to further improve its effectiveness. This is why mass AND gas permeability are both so important. Getting the right stuff the right distance from the the right part of the right wall for the frequency youre trying to kill is the name of the game. It a crap name, I know, but thats what it is.
Traps are most effective in points of biggest buildup (corners) and points along the walls that correspond to antinodes of the main frequencies youre trying to hit (i.e. where that frequency is loudest). Putting a trap in a node (where the energy in/amplitude of that frequency is lowest, theoretically zero) does little.
Membrane absorption is also quite easily implemented, though harder to gauge the right thing to do. The idea is that your traps are backed with a panel of something that freely resonates with the sound hitting it, taking energy out of it and reducing the mode. Ghetto versions include plywood, moderately heavy plastics, metal panels, anything else you can think of; the panel must be flexible and sufficiently heavy that it actually has an effect, but not so heavy or thick that the sound just bouces off it or cant make it resonate.
Helmholtz resonators are also possible and woth a mention for the more adventurous among you (till you take a bass trap to the knee). I have never made one myself, but the principles are these: Its sort of like the opposite of blowing over the top of a bottle (that is an example of helmholtz resonance, but a more general one, its use as treatment is much more specific): you make an air-filled resonator (tuned to a frequency you want to hit, with an equation you can find on wikipedia) and place it in an antinodal point. Probably a corner. The resonator is set off (like the bottle being blown across) by the mode, pressure in the resonator lowers as it 'tries' to produce that tone itself, and as a result sucks air in, relieving the pressure in the compression of the mode that set it off to begin with, dampening the mode.
Helmholtz resonance - Wikipedia, the free encyclopedia
You have to know what frequencies youre trying to hit with a helmholtz resonator, however, whereas rockwool/fibreglass is broadband and though you can cause trouble or do little with poor density choices, its easy to implement. As I said, I havent used resonators, but its clear that they could easily sit there doing nothing. How effective they are if you get them right I cant say, but in theory they should be very good and more space efficient. They will also have to be adapted for that room, however. Though as I type this a plan for a frequency variable helmholtz resonator is forming in my head; it should work in principle.
Before I go on to high end treatment, I'll mention that its quite possible that you have sorted your high end about as much as you can with the traps. High end and mids are easily absorbed by rockwool, so if you have rockwool traps at your reflection points you may well have done all you can.
-Edit: I forgot this first time round; that doesnt work the other way round. Thou shalt not stick an inch of foam with pretty pyramids or otherwise on the walls and expect it to do anything at all to low end. Cover the entire room in it and you will barely touch low end at all.
Also, The rooms response is not volume dependent. Sometimes you hear that if the monitors are quiet, they're not being influenced as much by the room. Not true. All the reflections and modes that youre dealing with in room acoustics are proportional to volume, they have the same influence at all volumes /edit.
Much easier. You dont really need mass, you just need to get some simple open celled foam (doesnt have to be dedicated 'acoustic' foam, though you know that will work right off the bat without buggering about with other stuff) and place it like so:
Any hard surface where you suspect there is a reflection path between you and your monitors.
Easy. You find them by placing a mirror on the surface and sitting in your listening position. If you can see the front of the monitor, theres a reflection path. Kill it.
A word about diffusion. This is breaking up reflections from a surface, sending them off in different directions at different frequencies and decohering them as a result. It has the benefit of being more 'live'; there are still reflections, its not dead, and it tends to make the reverb of the room more pleasing and larger. This can sound good. Its easier to kill everything and add verbs later, but arguably better (and certainly what you find in high end studios) to enhance the sound of the room through strategic use of diffusion. The worst you can do is put useless ineffectual diffusion where you could have put some usefull absorption. Easily reversed, low risk. Look up some designs and have a crack at it if you want. While I'm on about things like 'live' sounding and 'dead' sounding rooms, those of you with enough space may wish to make a 'Live End Dead End' room. That is a room where the monitoring end is all absorption and the other end, or another part of it, is diffusion or a combination of absorption and diffusion, for recording vocals, acoustics, even cabs can benefit if you like a guitar sound with a bit more space in it.
Just a quick word about EQ. Its not a one stop fix. Use it, especially if its on your monitors, but it and any room correction software or what have you is really a last stage fix: final polish. As a last stage fix they are generally very usefull, but do not rely on them, they can make things sound outright weird, improve a small listening position while wrecking the rest of the room and chew through your headroom trying to EQ in modal nulls. I will say that its much better for mid and high end overall balance fixes (as opposed to trying to fix comb filtering from reflections) than low end, but still not optimal in and of itself.
A couple of vids. There are lots out there, but these have two guys that seriously know what they're on about.
Bob Hodas on Dave Pensados 'Pensados Place'. As an aside, Pensados place is fucking awesome, though dave has nothing to do with metal, many methods can be adapted or are universal, and his show is superb. Watch it. OT: Bob hodas is a guy that people that can hire absolutely anyone hire to tune their rooms. He knows his shit. You listen to him.
A small rooms vid from real traps. Real traps sell acoustic treatment and this is more or less an advert, but it contains a lot of very good information, and RT head honcho Ethan Winer is really big on actual evidence, rational analysis of a room and can be found helping people out on forums for absolutely no gain to himself (hes given me advice for the asking before, when it was clear from my questions (about DIY treatment) that I was not gonna buy his stuff). Hes one guy that is trying to sell something that I think you can trust and also seriously knows his stuff. I own no realtraps, btw, I'm selling nothing, I'm just trying to impress upon you that hes to be listened to. The RT vids are cheesy, deal with it, and often funny (especially ethans eyebrows). One of them has a stripper though. Its niether of these, so go find it. Consider it an acoustically educational boob-hunt
Hope that all helped.
Last edited by MDV; 02-25-2012 at 06:56 PM..
|02-21-2012, 11:11 PM||#2|
GIVE DEEZ PEEPL AYUR
You need to replace your Orange bass trap with a Zilla bass trap.
|02-21-2012, 11:12 PM||#3|
holy wall of text Batman! bookmarked ofc!
Don't worry about people talking behind your back, it just means you're one step ahead and they're in perfect position to kiss your ass!
|02-21-2012, 11:16 PM||#4|
MG Server Overlord
|02-21-2012, 11:23 PM||#5|
and well deserved
|02-22-2012, 02:38 AM||#6|
Cheers. I hope its useful.
|02-22-2012, 05:42 AM||#7|
Is Actually Recording
Awesome read - this was my trainride home.
"They can kill you, but the legalities of eating you are a bit dicier." - David Foster Wallace
|02-22-2012, 11:24 AM||#8|
Toaster this, bitch
Everyone knows Mesa makes the best bass traps.
Making metal every night and day.
|02-23-2012, 04:37 AM||#9|
Also, monitor height and angle. Dont forget that! (like I did before, should be pretty obvious that its another placement variable though).
|02-23-2012, 12:52 PM||#10|
Toaster this, bitch
Mark, what do you find or expect the effect of monitor angle to be? I have adjustable stands and could have the monitors at, above or below my head with angled foam to adjust angle and get the acoustic axis of the speakers in line with my ears. I'll measure it, but I suppose there might be more to it than the frequency response changes.
With the speakers above my head and firing down, some of the first reflection points are on soft stuff behind me..
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