ethan's articles

[hookiefree]

With Rick and other's help I came to the conclusion not to sweat all that. I'll just put up more RF panels until somebody else figures it out. Whatever the end all be all solution is, I'm sure RF will be in the equation somewhere and I'll be ready.

Sux about your rep point. Would loan you one of mine if I had one.

 

[Farview]

There is more than one way to skin a cat. The idea is to break up or absorb direct reflections, room modes, resonances, and flutter echoes. Some methods work better (diffusion or absorbing) than others depending on the problems in your room. Your room is different than my room so what works for me might not work for you. It is confusing because the 'perfect' answer is so dependant on your unique situation that it seems like you are getting conflicting answers to the same questions.

 

[FALKEN]

Jason,

that makes more sense than anything so far.

except, I am mixing in what is supposed to be a bedroom with 8' ceilings. it is not so "unique".

 

[Farview]

You control room is unique. The bookshelf you mentioned has an effect on the acoustics. The window (assuming there is one) placement in relationship to your speakers and your ears has an effect. If you move your mix position back or forward 6 inches, it will make a difference. Hell, whether or not you have the door to the closet or the hallway open will make a difference.

Even though it seems like you are doing the same thing as everyone else, there are enough differences to make your situation unique.

 

[FALKEN]

Even though it seems like you are doing the same thing as everyone else, there are enough differences to make your situation unique.

Great.

I see what you are saying.

I always sort of laughed at the people who had foam on their walls like, "is that really going to keep you from sucking??"

Then I come on this website and read how important it is, and I say to myself "..okay. I'm not going to be completely close minded...I'll read into it and see if there is any merit."

Well, nobody knows what is what. what works and what doesn't. or maybe there are a few things that work. but one person's definition of "work" might not "work" for me, as a matter of taste. or as a matter of where my goddamn chair is.

So now you have all helped me come to the conclusion that everybody who has this shit on their walls has pretty much fucking guessed.

psychology tells us that when you spend a lot of time and/or money on something you are likely to back it up even if it does suck.

so I guess now you are going to tell me that what I really need to do is spend a few hundred bucks and build the shit and just move it around till it sounds right. right?

sorry If I am coming off as frustrated, thats just what I am. nobody here's fault but my own..

 

[Farview]

There are also different solutions for a mixing environment. A reflection free zone has the walls angled in such a way that reflections never make it to the mix position. That doesn't use as much absorbsion because you are deflecting the problems away from you. My old control room was a live end/dead end room. That is basically having the front of the room dead with a lot of absorbsion and having the back of the room live with diffusion. Both of these types of control rooms are great to work in, but are completely different as far as how much foam you need.
The main objective is to get rid of anything that will get in the way of you hearing exactly what is coming out of your speakers. How you get it done isn't that important. You just need to get it done.

 

[RICK FITZPATRICK]

yes rick i have read your rants as part of my research. very humorous stuff. which did you end up doing? I dont have 5 years to spend on this!!!

Which did I end up doing? NONE. I had to move two years ago, and haven't had the time or money to do what I'd REALLY prefer to do since then. Which is build from the ground up. As far as treating existing rooms is concerned, that was the reason I came here in the first place, but time and money have constantly put off doing what I THOUGHT I wanted to do. But let me explain something to you.

In the late 80's, I found a book called The Master Handbook of Acoustics, written by an acoustician named Alton Everest. Within that book were some chapters on current control room and studio acoustical TREATMENT and design DOGMA. Actually, now I consider it DOG CRAP. One of these chapters was on Diffusion, of which he explained current use of in control rooms AND small rooms period. He even went so far as to insert pictures of current control rooms AND the RT-60 tests, showing how the use of diffusers in these rooms, created a dense diffuse soundfield with a smooth decay rate and a pronounced TIME DELAY GAP. I was astounded. Within these chapters was what I thought was the "Holy Grail" of studio design. Mind you, very little was referenced to absorption, especially in a studio. However, the space given to diffusion, and especially quadratic residue/prime number sequence type diffusers was significant.

Having no background in acoustics nor studio design, I was thrilled to find this, as it appeared that the "secrets" of REAL studio acoustics was in my grasp. What wasn't in my grasp, were the mathimatics involved. I spent a great deal of time unraveling these "principles" and math, only to discover 5 years later, that it was all bullshit. At least some prominant studio design people said it was. In fact, a well known acoustician told me his opinion of the book and it WASN"T good!! That happened within a year of joining this bbs. Thank god I didn't spend money I didn't have(loans) building shit based on trust in "professional acoustician" word. I'd kicked some "professional" ass!!

Now I don't know about any one else, but when I buy products or services based on trust in the so called "credentials", and that trust gets destroyed by
evidence that these so called "truths" were bullshit, I get pissed. No, let me rephrase that. I get damn right OUTRAGED!!!. Hence some of my rants here.
To this day, I am STILL trying to track down the REAL science based answers. But as you have just began the journey through the rabbit hole, you are beginning to see the tip of the problem. Disagreement even among professionals is ...as far as I'm concerned...evidence of less than ethical behavior on one end, and TOTAL MALPHESANCE on the other. Its like this. In the last month or so, I've read things that suggest the following
1. Companys who build acoustical products give product "rating" sheets based on tests, and these tests are based on "STANDARDS" which state how and where these tests are performed. And UNLESS you purchase and read these standards, the test results and RATINGS have absolutely no meaning at all. In fact, the results from these tests can be manipulated in such a way as even other professionals can NOT make companys admit to unethical behavior, as they are ONLY ethical in the sense of SCIENTIFIC PROOF, which if you dig deeper into the scheme of things, is actually in the mind of the believers. The "standards" do NOT provide a way to actually prove a damn thing. The test results are given to the company, and they can do with them whatever they please, including, according to a competitor or scientifically accredited individual, leading you to believe one thing, when in reality it is totally false. However, they can't back up their statements CONCLUSIVLY. ONLY by virtue of the standards, as the standards are what ULTIMATELY govern under what and how tests are performed. What is unfucking believable though, is it still boils down to YOU accepting THEIR word as gospel.

2. Profit based professional consultation can and IS routinely based on experience, NOT scientifically proved fact. And if you are given an INVOICE for services rendered, whereby this consultation is administered through construction documents, you have been victimized in the sense that if you CAN'T prove their consultation is incorrect, then they get away with the same thing unethical companys do, as it is THE EXACT SAME THING.

SO WHO THE FUCK ARE YOU GOING TO BELIEVE?

And don't tell me it doesn't happen. I have been fortunate enough to ask direct questions on other forums where I have been "enlightened" to this very fact.
This is why it REALLY took me so long to make decisions.


Let me give you an example. On this very forum, for 3 years I read, and still do currently read suggestions of using rigid fiberglass across corners as a bass trap. Various science based reasonings for doing so have been posted as FACT, of which I am guilty. However, it wasn't untill a few months ago, actual tests were made at the expense of a reputable acoustical products company on this principle. These tests were simply a comparison between various products of other manufacturers, and DIY designs based on hypothisis of educated people in the field of acoustics. However, since there is NO valid standards for this type of tests, the results are NOT really worth a damn. Only what they tell you as far as a comparison. NOT as a test based on standards. So, where does that leave US? Your guess is as good as mine. This is why in a couple of months, KNIGHTFLY is going to bring his ETF(EFT?) test software over to my little old room, and WE"RE going to see EXACTLY what is going on. I'm building some acoustical devices to see what happens. Lord forbid. I'f I actually can SEE what takes place, I'll be in seventh heaven. Untill then, its the same ole shit. Believe what your recordings TRANSLATION tell you I guess. Hahahaha!!
Well, there you have another rant. Good luck with YOUR decisions.

To whom it may concern. My "opinions" concerning the state of the "acoustical" industry are that and that only. Opinions. However, they're damn well as good and NO DIFFERENT as what I read regarding the "opinions" of some of these same people.
fitZ

 

[c7sus]

Build slot resonators and you get absorbtion and diffusion together.

And it ain't some fancy new technology. Helmholz published his ideas over 75 years ago.

http://www.johnlsayers.com/HR/index1.htm

 

[apl]

Hey, Fitz, I've been one of those schmantzy consultants in a very closely related field.

The tests are what they are, and the data is accurate. But the tests do not reflect real life application of acoustic materials. It's up to the acoustician to apply those materials to meet the client's needs.

One important point is that there is no consensus on what a "perfect" studio room should sound like. Some like them lively, some like them dead. Some like to have choices and flexiblity. So your guy who wrote the book wasn't factually in error. Prime sequences and stuff are cool but overkill for most situations. Really, if you can get most of the modes out of a room it will be satisfactory for recording.

 

[FALKEN]

In fact, the results from these tests can be manipulated in such a way as
even other professionals can NOT make companys admit to unethical behavior,
as they are ONLY ethical in the sense of SCIENTIFIC PROOF, which if you dig
deeper into the scheme of things, is actually in the mind of the believers.

reminds me of an old song about detergent and cigarettes...

2. Profit based professional consultation can and IS routinely based on
experience, NOT scientifically proved fact. And if you are given an INVOICE
for services rendered, whereby this consultation is administered through
construction documents, you have been victimized in the sense that if you
CAN'T prove their consultation is incorrect, then they get away with the
same thing unethical companys do, as it is THE EXACT SAME THING.

Hey man, just because you hire a lawyer doesn't mean you're not going to
jail.

Whether or not a professional could come in here and make my room sound
amazing or not is irrelevant. this is "home" recording dot come.

However, since there is NO valid standards for this type of tests, the
results are NOT really worth a damn. Only what they tell you as far as a
comparison.

I read that thread. Comparison is all we have. why would you try to
quantify sound and music into formulas anyway? something either sounds good
or better...or crappy. or thick or thin or wide or whatever. comparison is
what its all about, man!

Really, if you can get most of the modes out of a room it will be satisfactory for recording.

Now, this is accomplished with bass traps right? and the broadbands are just to accelerate decay time and thin out reverb? and maybe reduce a little comb filtering? is the bass traps also to reduce comb filtering?? and the broadbands don't "get the modes out" right?

Just trying to short out what is what so I know exactly what I am getting with each treatment.



By the way I emailed tech support at the manufacturer of my monitors. The manual said to place them in an equilateral triangle with my head but not how far away. I asked them if they would recommend bass trapping and/or a reflection free zone for use with their monitors. Maybe this will shed some light on the subject.

 

[apl]

Now, this is accomplished with bass traps right? and the broadbands are just to accelerate decay time and thin out reverb? and maybe reduce a little comb filtering? is the bass traps also to reduce comb filtering?? and the broadbands don't "get the modes out" right?

Bass traps get rid of low frequency modes. Diffusion gets rid of mid and high frequency modes. Then some absorption to keep the decay times reasonable, and you'll be fine. When you're recording you can control how much room ambience makes it into the signal by adjusting how far from the mic the source is.

 

[FALKEN]

Bass traps get rid of low frequency modes. Diffusion gets rid of mid and high frequency modes. Then some absorption to keep the decay times reasonable, and you'll be fine. When you're recording you can control how much room ambience makes it into the signal by adjusting how far from the mic the source is.

If I like long decay I can skip the absorption then right? or maybe just do part of a room, so I can put maybe guitar and bass amps there...
maybe the portable absorbers would be better for me than the wall hangers? these would accomplish the same goal, no? only I can have more control over the amount of decay?

then put bass traps and diffusors in the control and tracking rooms to get rid of the nodes, and a RFZ in my mix position?

 

[Farview]

If you record and track in the same room, this would be a good idea. You could put the treatments on stands or hang them on the wall with hooks, so you can take them down easily or rearrange them depending on what you are doing that day.

 

[FALKEN]

Build slot resonators and you get absorbtion and diffusion together.

And it ain't some fancy new technology. Helmholz published his ideas over 75 years ago.

http://www.johnlsayers.com/HR/index1.htm

truuue...
i can't seem to make any sense of those diagrams though; I am not a very 'crafty' individual. at least I know my limitations...I am not sure I could actually build one of those.

 

[Ethan Winer]

Folks,

Wow, a lot can sure happen here in one day!

FALKEN:

> do you want to put absorbers near your monitors or diffusers? <

You don't want either "near" your monitors. Setting aside bass traps for the moment, the important places to put absorption or diffusion is the early reflection points. These are on the side walls and ceiling about halfway between the speakers and your ears, and possibly on the rear wall if that wall is less than about 10 feet behind you. Absorption is used more often than diffusion for several reasons.

First, all small rooms need absorption more than diffusion because a small room tends to have a boxy sound with too much crappy sounding ambience. (Yes, "crappy sounding" is a technical term.) Diffusion is great in larger rooms where there's enough volume to send the diffused sound toward. This is not to say that diffusion is never useful in a small room. But that brings up the other reason diffusion is less common: Good diffusors are complicated to build and are thus much more expensive than good absorbers. I've heard good diffusors and cheap diffusors, and the good ones cost a lot (or are hard to build yourself) and the cheap ones sound worse than a bare wall.

Either device can solve the problem - which may seem surprising! - and that problem is a boxy sound caused by reflections off nearby surfaces which shows up as comb filtering. However, at low frequencies diffusion is neither practical nor desired. Below about 300-400 Hz the big problems are a severely skewed response and ringing that makes bass notes run into each other making a muddy mess of things. All rooms need a lot of bass trapping.

Rick:

> I found a book called The Master Handbook of Acoustics ... now I consider it DOG CRAP <

That book is hardly dog crap. There may be one or two things proposed that are less common today, but the basics are solid and well presented. One of the biggest problems with many classic studio design texts, and likewise many "classic acousticians," is they fail to address (or even understand) the problems unique to the very small rooms commonly used today. Designing and treating a professional control room that's 35 by 40 by 17 feet is completely different from how you handle a bedroom.

> the test results and RATINGS have absolutely no meaning at all <

That's not really true either. Sure, you have to be willing to educate yourself a little, but this is true with anything. I know you've been around long enough to remember the fiasco 20+ years ago about power amplifier output ratings. The most important spec is continuous power, and all amps can put out much more power for a short burst. Burst power is important too, but not nearly as much as continuous power. So amplifier manufacturers would tout specs like 400 watts even though the amp could sustain that for only a few milliseconds.

Likewise for automobile mileage. Sure, a car maker can claim 45 MPG, but you'll never achieve that unless you drive the same way as the testers do. Heck, the phrase Caveat Emptor has been around so long it's still expressed in Latin!

When testing absorbers in a certified lab there are few variables. If enough material is tested so the presence of the material makes a sufficient change in the lab's reverb time compared to empty, the results will be accurate. Yes, they may vary from lab to lab, and placement within the room is another factor. But tests in reverb rooms are far from useless.

Also, as apl explained, "there is no consensus on what a 'perfect' studio room should sound like." And this is probably the biggest reason you're having trouble finding agreement. But that doesn't mean the parties involved don't know what they're doing! It's entirely possible to have two different designers make completely different rooms using different design goals, and yet both rooms will be eminently useable.

--Ethan

 

[FALKEN]

If you record and track in the same room, this would be a good idea. You could put the treatments on stands or hang them on the wall with hooks, so you can take them down easily or rearrange them depending on what you are doing that day.

I track vocals and guitars and bass in my control room. I track drums and band practices in the jam room. there is only so much I can ask my girlfriend to do in the studio!


so I think I know where I would place the absorbers for the RFZ and the Bass traps, and where to position absorbers for tracking...

where should I put those diffusors? Most of what I have read on them says they go behind the monitors but obviously that is for a different purpose.

 

[apl]

If I like long decay I can skip the absorption then right? or maybe just do part of a room, so I can put maybe guitar and bass amps there...
maybe the portable absorbers would be better for me than the wall hangers? these would accomplish the same goal, no? only I can have more control over the amount of decay?

then put bass traps and diffusors in the control and tracking rooms to get rid of the nodes, and a RFZ in my mix position?

Yeah, you could make a couple of panels that would be soft on one side and hard on the other. When you want more absorption, put the soft side out. When you might a livelier room put the soft side against the wall.

 

[FALKEN]

Ethan,

thank you very much for helping to clear these things up. but it seems like every time you post you create more questions than you answer!!! I never seem to know when you are talking about tracking or monitoring...

First, all small rooms need absorption more than diffusion because a small room tends to have a boxy sound with too much crappy sounding ambience. (Yes, "crappy sounding" is a technical term.)

I have a small room (control room) and a big room (jam room). the big room actually has only 2 full walls. the other 2 walls have about 80% cut out from the middle. so it has 4 corners, but 2 walls. I really like the sound in both rooms. the entire house is tile and I think the reverb sound is great. I do not want to kill it. It is not overly bassy either.

Below about 300-400 Hz the big problems are a severely skewed response and ringing that makes bass notes run into each other making a muddy mess of things. All rooms need a lot of bass trapping.

this might be a long shot, but low cut switches on my mics (during tracking) and monitors (during mixing) don't help the situation?

 

[Ethan Winer]

FALKEN,

> it seems like every time you post you create more questions than you answer!!! <

I'll take that as a compliment.

> I never seem to know when you are talking about tracking or monitoring... <

I had control rooms in mind when I wrote that post, but a lot of it applies to tracking rooms too. For example, comb filtering caused by reflections off nearby walls is a problem for sound coming from speakers and also for sound coming from instruments.

> low cut switches on my mics (during tracking) and monitors (during mixing) don't help the situation? <

No, because the problem is not that low frequencies are accentuated, but rather that the low end response is riddled with numerous peaks and nulls. The graph below is from one of my EQ magazine articles, and shows the response in a typical (16 by 10 feet) control room.

Note the peak/dip pair at 110 and 122 Hz where the response varies a staggering 32 dB across a range smaller than one musical whole step. You can't fix this with low-cut switches.

--Ethan

 

[FALKEN]

Note the peak/dip pair at 110 and 122 Hz where the response varies a staggering 32 dB across a range smaller than one musical whole step. You can't fix this with low-cut switches.

I am pretty sure I can cut that shit!!!

heck! most rock guitars on the radio today are cut up to 300 hz it sounds like!! vocals too!

but I see what you are saying.

so If I choose not to put up broadbands, I will still have nodes?

and say in my jam room, there are 2 very large parralell walls with huge surface area. would you kill the "standing waves" with broadbands or bass traps? And I dont understand how you could even accomplish this because of the sheer area of the walls...I would need a crapload of these things. I think you could lessen the situation, but not fix it.