Hi,
I'm trying to set up a little home studio. I have most of the equipment I want to use but the room situation is confusing me. Most of my options are fairly small square or rectangular rooms, which i've always heard are the worst sounding space. I'm really into natural reverb (stuff recorded in reverby churches, use of echo chambers, etc.) but it seems like there's no way to achieve good sounding natural reverb in my possible spaces since everything's so small and parallel.

So I was thinking about trying to make a totally dead room with a ton of absorption on the walls and ceiling. I figure if the room acoustics don't sound good, why would I want any of it to be picked up by the mic? My idea is to record everything totally dry in this room and then add the reverb and space to it later by sending it through hardware reverbs and by playing it into different spaces with good quality monitors and recording it with different mics (like an echo chamber).

So I'm wondering, does this make sense? I've been reading a bunch about acoustic treatment on this board and elsewhere and it seems like people often say you want to absorb a lot but not make it totally dead. Is this just because if it's dead it sounds unnatural and too dry? Is there anything else wrong with recording in a dead room? This is kind of the only solution I've thought of since I don't really want to use the sounds of any of the rooms that will be available for me to record in regularly. I want to be able to record in my house regularly but I'm fine having to find spaces to use as echo chambers later and put work into adding space, like as another step of the recording process.

Thanks for any suggestions about this! I appreciate any comments or ideas.

Some people prefer a lively room, but, as you mention, a small room [about 10' x 15' or so, I assume?] is probably not going to give you "liveliness" so much as a mess. I think a big part of why people don't recommend a totally dead small room is just that it's so hard to actually get a small room to be properly dead all up and down the frequency range. If you put the money and time and thought into doing it right, I think it's highly commendable. If you can cut the decay time of the lowest frequencies effectively, then you are free to strategically place higher-frequency reflectors around the room to tailor its sound to your preferences. It won't sound like an arena, but it can be nice.

Exactly. The size of the room dictates whether the "liveness" can be good. Small room ambience always sounds bad, and is best killed with absorption. Save for the floor or one other reflecting surface.

--Ethan

My room is 9'd x 12'w x 7' tall with concrete floor and cinderblock for 3/4 walls. Completely untreated its highly reverberant and not really in a good way. I made frames from 1x6 and filled with R19 insulation that stand in each corner and covering 50-60% of the entire wall surface. I put area rugs on the floor. The ceiling is a hard fiber board tile with R19 in the rafters above it and 2 sheets of auralex to handle reflections off of the ceiling into OH mics.

Its is very dead but seems reasonably balanced acoustically. Clap your hands in there and you don't hear any decay but you do hear the sympathetic vibrations from the drums.

I have been tracking acoustic gtrs and drums in there a lot of late and I am very please with the results. You do need to artificially simulate any reverberant quality you want on the instruments but that is no biggie. Techniques such as M/S still work but the effects are very subtle compared to more reverberant rooms I've worked in.

Hey guys, thanks for the responses, that all makes sense. I think I'm gonna move ahead with this plan. I'm gonna make another post asking for suggestions on the best way to make this dead room.

One question about what you said, Ethan: why would you leave one surface for reflecting?

Thanks again for the input.

Note: typically, the floor will always be reflecting. It's not very practical to cover the entire floor with 4"+ of rockwool or whatever. Carpeting only kills the highs and leaves the mud bouncing around, you're often better off just leaving the floor bare... or just using some area rugs here and there.

In sum, unless you wish to clutter your floor with thick bass traps, it will always be reflecting. This is why I personally like to trap the ceiling heavily to eliminate standing waves between floor and ceiling. A heavily trapped ceiling helps to tame whatever the floor is throwing into the room. (Still need to trap the walls too of course.)

Even in a small room like that, I probalby wouldn't go *totally* dead, just mostly dead. You want to leave a bit of liveness, working in a totally dead room is a bit disconcerting.

I'd do this by using broadband bass traps with a membrane to maintain a bit of reflectivity. Use full bandwidth absorption at reflection points and on the rear wall, and probably on the entire ceiling (or as much of it as you can).

Also just to add I would use diffusion in the back sideways, ceiling and back wall. For the back wall though you still want some THICK absorption to kill the nulls and peaks coming from that area.

...or add some gobos with diffuse side like I did. I used GIK's poly cylindrical diffusers on mind, but you could potentially use QRD's as well. They sound great and are very versatile.

Frank

In a control room, surely but I thought he was talking about a performance area.

If we are talking about a control room, forget everything I said in my previous post. Controlled reflections and solid bass trapping is a must but a certain liveliness is a good thing for mixing

As for the "live verses dead" issue, I think this is totally dependent on room SIZE. As Ethan often mentions, you really cannot get a VERY small room to sound good, thus it's best to make the room "disappear" with as much trapping as possible. I'd agree.

Diffusors are not going to work in a VERY small room, there just isn't enough physical space for waves to diffuse... and for a diffusor to even be effective at all in such a small space, it would have to be physically large (deep), then you'll barely have any space left to even fit your gear, etc... just doesn't work.

The only thing a super small room will give you are close reflections, this can only hurt. So, for such a room, you are pretty much forced to go 100% dead, because whatever liveliness can be dialed in can only be bad liveliness. This is my take on it anyway.

Though, perhaps if you had a room that was 8'X10' and you were willing to commit to covering an entire 8' wall with a giant 2 foot deep well-designed quadratic diffusor, perhaps this could work...???? You would then have only 8'X8' of usable space. No wait, you'd have only about 7'X7' usable space after you got done putting up good traps on the other three walls. I wonder how this would sound, because for those who just need what essentially is a "booth", this could be an option I suppose. I'd still be nervous about how such a radical set up would ultimately translate, in one regard it would be a very unusual arrangement, it may still sound a bit goofy. Safer bet... go 100% dead.

So then, the big question, how big must a room be in order to be eligible for effective and good sounding "live treatment"? I'll leave this question for the more knowledgeable folks to toy with. Like, for instance, perhaps any room of say 100 square feet or less with a ceiling of 7' or less is a lost cause in terms of attempting to add any "liveliness" and thus must be made 100% dead. But maybe anything over 200 square feet with an 8' ceiling or higher approaches the range where well designed diffusion might actually be "musically" effective...? What say you?

my opinion is that unless you sacrifice some very serious space for bass trapping, you are never going to have anything near a totally flat bass, whereas if you cover your room with, say, 4" of OC705, you can pretty much deaden it in the mids and highs... so now we have a dull sounding room which might lead us to mix too bright.

real traps, for example makes a trap with a reflecting membrane of some kind on the front facing surface and one of the things that does is to reflect some of the mids and highs back into the room.

my .02,

That's a good point, and it's definitely true in the mid-size to larger rooms. In a small room I still say that the only option is usually to make it as dead as you can get it. Small rooms just sound bad...getting more reflectivity out of them is just not what you want.

Frank

Thanks for all the responses everyone.

Just to clarify, I'm not talking about a mixing room at all. This room would be for recording only.

Just as a related question...

When studios are built for mixing surround, they're usually much more dead that regular 2.1 mixing studios since in surround the idea is to add in most of the ambience and reverb you want.

If someone wanted to mix in stereo inside a dead room equipped with 5.1 speakers, would there be anyway to find a neutral reverb you could apply to different channels that could reasonably mimic a properly sized room with diffusion (obviously not as a substitute by any means, but just a step in the right direction if the room is too small and you've got the budget for 5.1).

Theoretically, a surround impulse response of a good stereo studio (with measurements taken at where you'd put surround speakers in your studio) might work, but I have no idea if that's ever been tested in any capacity.

Recording what? You can get away with a bad room with softly picked acoustic guitar, but not with rock drums. In that case "dead" is absolutely, positively a better option than bad room sound.

Frank

Wow....Not sure where to wade into this one!

Is a "dead" room useful? Sure, if you are making anechoic measurements without gear sufficient to window out reflections!

As no one seems to have made any attempt to define the problem being addressed, nor the goals desired, we seem to have utterly confused destructive specular reflections and room modes with the sense of space a later arriving semi-diffuse soundfield imparts to a small acoustical space.

And "small room ambiance always sounds bad"???

Techniques do indeed exist to address BOTH issues without ending up with a claustrophobic anechoic chamber as if it were some kind of a panacea solution!

Adjacent rooms, storage areas, closets, hallways, attic space, area above a suspended ceiling, etc can be coupled to the main space by the use of phase gratings - similar to their LONG time use in light physics - only of larger size to accommodate the longer audio frequencies!

A simple example of a commercially available phase grating is the pArt Science space couple. And the use of a phase grating has myriad uses if one is simply aware of the behavior of sound (or light) waves through an appropriately sized phase grating.

And while the mathematical behavior of the phase grating is beyond the scope of this thread, suffice it to say that it allows sound at near normal incident to pass through unabated whereupon it bounces around in the coupled space, becoming more diffuse and losing energy and then re-emerges upon a later reflection where it is again near normal incidence to the phase grating.

At other than normal incidence (normal meaning perpendicular-> 90 degrees), the depth of the grating functions roughly the same as an absorptive medium where the effected wavelengths begin at ~4 times the grating depth (and adjusted for the appropriate angle of incidence).

Thus one is able to address specular reflection within the room proper and to also add a later arriving, lower intensity diffuse field to the room!

And all I can say regarding the proposed anechoic chambers so many are want to build is - aside from testing equipment - "get me out of there".heh

Okay, wait a sec here. We're using some short hand language for sure, but you're going into a kind of detail that the OP is not really asking for. He's wanting to set up a "small home studio", so doing the things you're suggesting are probably well beyond the scope of work.

Understand that we're trying to do the best thing for people with limited budgets and spaces that are far from ideal, and trying to use language that's as comprehensible and common as possible. Of course that side steps a certain level of detail, but it's a level of detail that's not particularly helpful to the average lay person.

Frank

The use of phase gratings to couple spaces - via their substitution for a closet door, or a ceiling cloud, or as an interface to any adjacent/adjoining room or space is anything but complex! While it can be VERY effective!

Heck, if one wants to become creative and to do a bit of experimenting, their addition to absorptive material can even enhance its effect...but now I am wandering afield a bit...

But then, maybe the term "phase grating" is a bit intimidating to some - sorry - but that is what they have always been called - for a visual, think of the divider grid that separates Christmas tree balls in a box - that's essentially a phase grating.

And this can be done by anyone aware of what they are doing - which I would hope is somewhat of a prerequisite for any well defined project.

Sure, you're right...it's not complex, but again, it's probably outside the scope of work for the OP who would likely have to cut through sheet rock and find some way to install these in the ceiling, walls, etc.

Frank

No. 2.1 control rooms built to current standards (formally called "recommendations") the reverb time is the same for 2.1 and 5.1. EBU 7276 sereies standards show this explicitely. If teh control rooms are not built to these standards then they are unique upon themselves and require unique ways specific to the room to modify the acousitcs.

It would be easier to temporarily bring in diffusors and reflective panels to adjust the acoustics.

Andre

So cutting strips of 1/8" luan ply and routing small 1/2 width channels every so often (dependent upon the opening size), assembling the strips into a grid, and nesting the strips within a frame is too difficult?

OK. Then I guess this topic will exclude those who should not be handing a hammer, drill, or screwdriver as well (heck, to have a bit of fun with this, let's include tooth brushes as well!) - and including those who might chose to buy the ready made panels!

I just persist in the notion, howver unfounded it may be, that folks can sometimes do amazing things if made aware of options and concepts that can be readily learned if there is reason to pursue the appropriate use of such techniques.

(Edit: I am not representing ANY commercial entity!)

That's not what I said. I didn't say that it was too difficult, I said that it was probably beyond the scope of work for the average user in an average domestic room, meaning that most of them simply aren't interested in doing that kind of thing. And hanging a panel is surely not of comparable complexity, is it? You're clearly an intelligent, articulate person so I'll take that as hyperbole.

What I'm saying in a couple of your posts is that the information you're posting is definitely interesting and certainly correct, but probably overly complex and not very actionable for the average person in the average domestic situation.

Also, as Ethan suggested it's probably a good idea to identify yourself in your signature line if you're a professional (as you seem to be), and certainly if you're PMing offers of things to people. Nothing personal...everybody just wants all the cards out on the table.

Frank

Anaechoic Room
http://en.wikipedia.org/wiki/Anechoic_room

First, your reply was sequitur to a post regarding the use of phase gratings - something that can be made without too much difficulty, or which can certainly be purchased by the "average" , if somewhat incompetent, reader!

And my reply followed parallel structure in response! (maybe that is part of the source of our digression...?)

But now apparently we have so many issues combined into one general assertion.

No, I don't assume that most or all here are intimate with the foundations of acoustical physics, nor of the more advanced acoustical measurement or modeling platforms.

Nor do they need to be, as it is more than practical for the average person to have a qualified and competent operator perform such measurements for them. But then, understanding the basic tools and what information they provide is not difficult - and it can be quite informative!

But then, few are going to be afforded that opportunity if they do not even know they even exist!!! And like it or not, the area of acoustical physics has literally undergone its own 'quantum leap' over the past 40 years since Heyser introduced TDS. Unfortunately. far too many are still persistying in holding on ever sop tightly to outdated notions for lack of an awareness and understanding of better models - which do indeed exist.

Wow, and so many seem so concerned about my affiliation in the industry...

As stated, I am glad to divulge any personal information one on one via personal communication. And I can even drop some names if that will impress anyone...

I don't claim to know it all! And I am not selling anything!

I am not representing ANY commercial interest. I am simply representing valid and more recent proven and applied acoustical 'notions'...known by some, and still unknown to others.

But how do (for just a tip of the iceberg) a couple of degrees in physics (trust me, it gets worse ;-), an extensive background in professional music, internal design of massively parallel computers, directed research and classified product development in optics and communications, and business - as well as operational proficiency and application of the various platforms for over 20 years count... for a start? Oh, and I have read a few copies of Mix, Live Sound and ProSound News...Does that enhance my credibility?

But I assume that if I mention something confusing or unknown, that if one is curious enough, they will PM me and ask for a better explanation. And I am glad to try to help. I would rather try to expand their concepts and understanding rather than to assume that " it's probably outside the scope of work for the OP who would likely have to cut through sheet rock and find some way to install these in the ceiling, walls, etc."

If it is, they are welcome to PM me and I will take as much time as is reasonable to try to further explain it on a level with which they are most comfortable.

I will present ideas, and I trust individuals can determine themselves what they are capable of doing. I am not going to dumb it down based on my assumption that 'they' are too stupid or incapable! That's not for me to decide.

So, dare I ask, is anyone interested in the acoustical concepts???



(Edit: I am not representing ANY commercial entity!)

You're clearly well qualified. The way forums usually work is that industry professionals identify themselves to avoid the perception of shilling or agenda-based posting. That's why Ethan, Glenn, and I identify ourselves...so no one can accuse us of an ulterior motive.

My question isn't whether you're right or wrong, or know what you're talking about or not. My question is, what do you expect people to do with this information? It's way, way over the heads of 90% of the readers.

Frank

What do I expect?

Nothing. ;-)

But perhaps those not heretofore familiar with some of the readily available information might be tempted to learn more and to possibly expand their comfort zone... and, if they aren't too careful, perhaps learn something useful!

And it certainly doesn't prevent anyone who is not familiar with some of the information from becoming aware that there ARE more useful and powerful measurement systems that are ROUTINELY employed in both the design and analysis and treatment stages. In fact, for the professionals, these tools are the norm rather than the exception!

Where do you think almost all of the diagrams available in texts such as the Davis & Patronis Sound System Engineering and D'Antonio & Cox Acoustic Absorber and Diffusers originate? But perhaps the readers aren't smart enough to read or understand them either?!

These aren't new! Nor are they exotic! And just because the average storefront chooses not to employ them, does not make them too elaborate or advanced!

I must admit to growing a bit tired of the attitude that the readers are too simple or incapable of understanding this stuff, when just a few minutes spent learning how to read the measurement will teach them loads of information! Heck ETCs are well within the range of EVERYONE on the forum, and their use inestimable! And the basic understanding of the primacy(but not exclusivity!) of the time domain for most acoustical issues is easily understood. (And please don't try to counter with an advocacy for the legitimate uses of the frequency domain!)

In fact, not one of the issues I have thus far presented is not addressed in Sound System Engineering!

And if someone wants to take a sip from the firehose, sign up for one of Pat Brown's SynAudCon seminars! This stuff has been explored and taught there for over 30 years! You can get it just like Alton Everest did when he attended the seminars and subsequently included the advances advocated in his texts!

But as far as this stuff being too advanced for the readers...while I find that insulting, I will let them decide that! The validity of the concepts nevertheless stands.

And its more than time to move on to the acoustical issues. If you have any personal issues, PM me!

(Edit: I am not representing ANY commercial entity!)

Indeed they do, and though you're implying that I'm calling the reader stupid, that is not in any way intended or implied, so don't put words in my mouth.

I think you're missing my point, so let me make it another way: I spent a number years in signals intelligence sourcing a variety of military and government agencies. There is, of course a vast array of information out there to be gathered, but we had to parse through all of the available stuff to find the *actionable* intelligence. In other words, it's not enough to just know something; you have to know what to do with it next or it's just noise.

Of course the reader can propositionally understand what you're saying, but you have to help with what to *do* with it. Knowing how to use measurement tools and read the subsequent plots is great, but what do you *do* about it afterward? What I'm saying is, I'm seeing a lot of technical information from you, and it's all perfectly accurate, but no practical solutions to the issues they expose. You've said that absorption is not the end-all, be-all with respect to acoustical solutions. I agree. What are your other suggestions?

Frank

Sorry if I have not been more forthcoming with specific solutions to so many general amorphous questions.

And I guess you mean more than simply 'absorption'?

Hmmmm...seeing as there are a myriad different legitimate intended uses for a room for which we have not defined...

And ignoring the specifics of a space...

First of all, there are MANY types of absorbers!

And in more cases than not, to generalize, I would use far more 'frequency selective' absorbers than broad band absorbers for the simple reason that I would seek to maintain a more robust semi-reverberant field.

And given the constraints of the room, such as sound transmission issues, or ingress, or systems noise levels, etc.......

And I would use absorption surgically to address these later arriving reflections, be it for establishment of an initial signal delay gap or the later arriving semi-diffuse soundfield. And to the degree possible, I would employ diffusion (of which there are MANY types) rather than absorption to the greatest degree practical in order to establish a well-behaved semi-diffuse sound field..

And the selection and combination/permutation of these treatments to achieve the desired verifiable goal, is the art of the science.

One doesn't just specify a one size fits all kit. rather it is a more holistic approach that includes all the aspects of a well defined goal.

Its not that difficult with good measurements. They tell you what the problems are and where they are located! Then you identify the various tools and options that address the identified problems. The art comes into play when you factor in other constraints such as aesthetics. And dependent upon room topologies and imposed factors such as the user wants to sit "here" and the desk must be "there" - never mind that he is in a null...and that he insists that he use a dipole line array in the near field in a tiny room (think I'm joking??)...you deal with it as best you can.

And given that the acoustics were the last thing thought of in the the planning of a space - as they so often are, you settle for the shortcomings inherent in such an ill-formed project that more often then not could have been avoided by more thorough and proactive planning.

Great post...thanks for that. And about the dipoles...you bet I believe you. I deal with that very situation more frequently than I'd like.

I also agree that it's more complex than a one size fits all solution, and I also admire your attention to the aesthetic requirements of the space. The best rooms are the ones where both of these legitimate arts work sympathetically.

The importance of great design cannot be over estimated. I'm looking forward to your contributions in this regard.

Frank