Soundman2020 - Studio Design Forum

Hi everyone.

This is my first post here and honestly, it is also the first time that I officially start a thread where i will deal with those who will have the pleasure of doing it as well as with Stuart whom I thank for the opportunity that he gives us in this forum.

My name is Lucio, i live in northern Italy and must necessarily let you know that it is really difficult for me to write in English, I am fairly good at reading, especially technical, but Google supports me on write.
I therefore ask you to have clemency with my probable errors, correct me if it will be possible.

I read and followed numerous posts in various forums where acoustics for recording studios are discussed, in particular that of John Sayers where I had the opportunity to evaluate the competence and availability of Stuart to always actively participate in giving advice and reply in very exhaustive way with posts that will often have engaged him for hours .... no one else has been so generous in that forum.

But .... let's get to the point, me and a friend of mine are sharing a nice situation (at least in terms of enthusiasm) that appeared to us last year .... We were in the situation of having to leave our previous situation with the recording studio, a situation that is certainly not ideal for recording and mixing but .... at zero management costs!
Everything worked for a few years but inevitably ... ended!
Our friends had started an ambitious project, 400 square meters of structure for exclusive musical use, 4 rehearsal rooms, a live room, a large "events" room and 2 control rooms, the largest of which will be the subject of this thread .
I asked Stuart about his availability in considering being able to support us in the layout, I must say that his availability was truly sincere, we have no financial resources to support such an ambitious project but we would like to be able to do our best by working personally and subtracting time from our work that gives us food .... which is not this.
Maybe I go a little further .... I just want to put those who, like us, find themselves in a similar situation, find themselves having to consult an acoustic designer .... it's a real delusion !! My friend asked at least 4 acoustic designers about this project ..... everyone was wary of undertaking DIY solutions, and although I can personally believe that there are very incomprehensible variables in acoustics and that experience dictates the rules .... I totally disagree with these positions, interacting with the designer is fundamental !! but our implication cannot be reduced to a mere executive work !!
Even if for the rest of our lives we will probably no longer need to build other recording studios or control rooms .... it is essential to understand something more and learn from the mistakes !! this is growth !! I must necessarily reiterate that Stuart is the only one who is much more sensitive in this sense.
It is absolutely right for a professional to ask for adequate compensation for his work, it is also important that the professional humanly consider having to deal with people who have a strong hobby in this scope and it is not fair to speculate.
Everyone draws their own judgments..... comments are welcome!
So, let's talk about things more related to what we have in common ..... our future control room was originally of dimensions:

L 8.05mt
W 5.20mt
H 3.44mt

We realized that we lacked the space to have a small storage for microphones, cables and anything else and proposed to Stuart hypothetical new definitive measures for the control room, being able to create a partition (with drywall) in the length bringing the room to L 6.30mt.

Obviously we documented ourselves in finding and proposing a measure that would at least meet the basic requirements about Bolt/Sepmeyer/etc compliance and Stuart confirmed our choice but he still found it interesting to be able to evaluate a measurement with REW before making the new wall that would reduce the length.

What I am attaching are the measures before and after the construction of the wall, I am not able to understand the differences well but I think Stuart will benefit from his precious comments. I also attach some photos of the room which has a rather large window on the right and a window towards the live room on the left side.
On Stuart's advice, we proceeded to create the entrance door centrally, the original entrance door was completely moved to the left on the rear wall.....
The actual and definitive measure of the room length is now 6.30mt.
This room will host an 5.1 analog console and a 5.1 speaker system(Focal) on the advice that Stuart will give us ..... I know that the solution for which we have asked for his help is not the simplest, despite this Stuart sent me his pleasure in sharing our experience in this forum and this .... makes us really more motivated

So....attached you can see the two measurements made with rew before and after the construction of the new partition which from 8.05mt in length has been reduced to 6.30m.
I really hope this thread can represent a reason for discussion or deepening for all of you, I really want to believe that the shared growth in this matter creates the opportunity to better understand the problems to be faced and understand when it is really the case to consult a real professional in acoustics. I will accept any kind of criticism, I am not a Stuart endorser ... be clear !!
I believe that the reasons that led me to contact him is sufficiently clear, I will not reply in any way to anyone who wants to feed intentions that do not fall within the technical merit, I have already read too many useless posts in the past (luckily not here) that no other purpose had if not that of deviating or syndicating affirmations .... I ask only to argue correctly and contextually. A sincere hug to everyone, even just for sharing my hobby.


All the best,

Lucio

Welcome to the forum Lucio! It's great to see that you started your thread!

As soon as I can, I'll add some of those REW graphs, to show some of the effects you mentioned.. as well as the typical response of an empty room!

and must necessarily let you know that it is really difficult for me to write in English, I am fairly good at reading, especially technical, but Google supports me on writ

Your English is just fine! It is WAY better than my Italian, that's for sure! So no problem at all.

My friend asked at least 4 acoustic designers about this project ..... everyone was wary of undertaking DIY solutions, and although I can personally believe that there are very incomprehensible variables in acoustics and that experience dictates the rules .... I totally disagree with these positions, interacting with the designer is fundamental !! but our implication cannot be reduced to a mere executive work !!

Unfortunately, your experience here is rather common. And your comments are very true! It is VERY possible for a musician, mix engineer, or pretty much anybody else with common sense and basic DIY skills, to build a studio. The important part is to get the acoustic design right. The actual building process is similar to any other home DIY project, with some differences that can be explained easily.

I don't understand why some studio designers are totally against DIY: it can work very well, and indeed if you look around this forum you'll see that it DOES work very well! Plenty of threads here that demonstrate that. And while I really do enjoy working on complicated designs for large facilities, I also want to do designs for "the little guy": Why should people with smaller spaces and limited budgets have to just give up and go home? There is NO reason for that! I know that some designers will not even consider doing anything for a room that is smaller than a certain size (often, their "minimum size" is very large!), and will not even consider doing anything for the DIY builder: I don't understand that. Perhaps it is because it is dead easy to design for a very large room? So they only want to design for rooms where the outcome is guaranteed to be good, just with minimal treatment, then they can bask in their own success.... The REAL challenge with studio design, is in small rooms, not big rooms. Big rooms are easy: small rooms are hard. The smaller it is, the harder it is. So maybe that's why those designers do not want to be involved in small rooms.... Afraid of failure, maybe? Or afraid of complexity? Or maybe they just don't want to take on any project that won't put big numbers in their bank account...

Anyway, that's not the way I see things: Even in a small room, and even with DIY building, it is VERY possible to get good results, and make the room usable. As long as the studio builder understands the limitations imposed by the size. There are ways, techniques, methods, and a process for treating small rooms, and the results can be very, very usable. I have designed treatment for rooms as small as about 10m2 (about 110 ft2), and the owners have been very happy with the outcome.

Sorry for the rant on your thread, Lucio, but it does anger me a bit that some designers won't even consider small studios with limited budgets!

Even if for the rest of our lives we will probably no longer need to build other recording studios or control rooms .... it is essential to understand something more and learn from the mistakes !! this is growth !! I must necessarily reiterate that Stuart is the only one who is much more sensitive in this sense

Thanks for the kind words, Lucio. Perhaps the reason I care more about small studios and limited budget, is because that's where I come from! Many years ago, I had to work in situations like that, so I do know what it is like. So I'm happy to work on small projects, as well as big ones.

our future control room was originally of dimensions:
L 8.05mt
W 5.20mt
H 3.44mt

We realized that we lacked the space to have a small storage for microphones, cables and anything else and proposed to Stuart hypothetical new definitive measures for the control room, being able to create a partition (with drywall) in the length bringing the room to L 6.30mt.

Right! And we get back to the same point as above here: The larger room would have been better, acoustically, but there is also a real, valid, important need for a studio to have storage space. So it's a trade-off here: you guys NEED that space for storing things, and there is nowhere else you could do that, so making the room smaller was an acceptable compromise. The smaller room is still very usable. I'll post the REW graphs that we got from the measurements in the big version and the small version of the room, so people can see the very real effect of modal response, and how it is directly related to room dimensions.

On Stuart's advice, we proceeded to create the entrance door centrally, the original entrance door was completely moved to the left on the rear wall.....

Right! The rear wall of any control room is, by far, the most important. And therefore it needs the most treatment. The critical parts of that wall, are the corners: that's the best location for deep bass absorption, which all small rooms need. Having the door near one corner would have used up the most valuable part of the room: moving that door to the middle of the wall means that both corners are now free for bass trapping. It also improves room symmetry a bit, and provides for better access paths into the room as well. Yes, having a large flat reflective surface on the back wall is not ideal, but there are ways of dealing with that...

This room will host an 5.1 analog console and a 5.1 speaker system(Focal) on the advice that Stuart will give us .....

Ahh yes... the multi-channel issue! This is important to mention: The acoustic design for a 5.1 room is very different from the acoustic design for a 2.1 room, for a very simple reason: with surround systems (5.1, 7.1, etc.) there are speakers at the back of the room, facing forwards... directly at the hard, solid, large, reflective surfaces at the front of the room! And therefore potentially sending strong specular reflections to the mix position, which would mess up the engineer's perception of direction, space, and frequency (because: psycho-acoustics... it's complex). So, the room has to be designed differently, to deal with that.

This is very important for other forum members and who think they might want to do 5.1 work at some point in the future, but will only do ordinary stereo 2.1 work initially: You can do 2.1 mixing in a 5.1 room with no problem... but you WILL have problems if you try to do 5.1 mixing in a 2.1 room. Thus, design your room for 5.1, even if you only plan to use it for 2.1 initially. Surround sound is a different animal.

So, in Lucio's case, the room will be designed for 5.1, and he will be using it as 5.1 right from the start.

I really hope this thread can represent a reason for discussion or deepening for all of you, I really want to believe that the shared growth in this matter creates the opportunity to better understand the problems to be faced ....

Absolutely! That's what the forum is all about: a place to see how the studio design process works, and what can be achieved... even with DIY!

I have already read too many useless posts in the past (luckily not here) that no other purpose had if not that of deviating or syndicating affirmations .... I ask only to argue correctly and contextually. A sincere hug to everyone, even just for sharing my hobby.

Well said!


- Stuart -

Great Stuart .... you always have nice words for all situations.
It will seem trite but ..... it feeds that enthusiasm that we all often need, too many doubts and discomfort we share every day, having a bit of it in one's fondness balances a lot.

We know very well that our "building" will require a lot of effort .... also economically, but to do so by nourishing the goal as well as making ourselves more responsible.

We await your evaluations, always...thank you


Lucio

Hello Lucio. 9 rooms in 400m2 sounds like quite a studio. Yes, it is good news indeed that you have Stuart onboard. I look forward to reading and seeing more as your studio build progresses.

As promised, here is some REW data from Lucio's place:

Lucio did some testing in the original, larger room, then again in the shorter room, after building the partition wall at the back. The differences in modal response are rather interesting, and perfectly illustrate how theory and prediction work out in real life.

First, here's the "theoretical predicted" and "actual measured" response of the original larger room:

The top graph is predicted modal response at the mix position, the bottom graph is actual modal response at the mix position. The close match is rather clear!

That's an important "caveat": Control room measurement is all about THE MIX POSITION! If you measure somewhere else in your room, then the modal response AT THAT POINT will be different. Even just moving away from the mix position by a few inches can show a large difference in response. This is why it is so important to set up your room with the correct geometry firstly, and then to take the REW measurements precisely in the mix position (where your head will be when you are mixing, and at the exact same spot every time, for every subsequent REW test. Because if you measure in a different spot, you will be measuring a DIFFERENT response, so you will not be able to compare the measurements.

Anyway, back to the top graph: the colored vertical lines mark the modal frequency predictions, with the longer red lines being lengthwise axial modes (modes that run between the front wall and back wall), the medium green lines being width-wise axial modes (left wall/right wall), and the shorter blue lines being height-wise axial modes (floor/ceiling). There are also tangential modes: there are tangential length/width modes that involve the front, back, left and right walls (yellow-gold colored lines), tangential length/height modes involving the front and back walls, and the ceiling and floor, (pinkish-purple colored lines), and tangential width/height modes involving the left and right walls, and the ceiling and floor (turquoise colored lines). And finally there are oblique modes that involve all six surfaces (silver-gray colored lines). Yep: modal response is complicated! However, usually you only need to be worried about the axial modes (red green and blue lines here). Those are the ones most likely to cause you grief in your room, with perhaps some lesser trouble from tangential modes.

There are a couple of reasons why some of those lines do not show any mode at all (for example, the first green line, which is the first left/right axial mode, is not there), because :

1. That mode is not present AT THAT POINT IN THE ROOM (see above...), but it might be present at some other location in the room. Thus, the "missing" left/right axial mode from that first green line at about 32 Hz... because the mix position is on the CENTER-LINE of the room! It is equidistant from the left and right walls, and thus MUST be in the null for that first mode! But it is NOT in a null for the second left/right mode, at about 65 Hz. Etc.
2. That mode was not triggered in the room, because of the speaker location (the speaker is in a null for that mode), or because there wasn't enough sound intensity at that frequency to trigger the mode. This is also why I suggest a higher level for doing the REW tests, than is suggested by the REW documentation itself: If you do the testing at a level that is too low, it might not trigger all the potential modes (and other acoustic artifacts), so one day when the room is finished and you turn up the volume "to check the bass", you suddenly start triggering modes you never even knew you had, and the room roars, or whimpers.... So I suggest a level of 80 dBC for each individual speaker (in 2.1, lower for 5.1) and 86 dBC with all speakers running... which just happens to be the standard calibration level for cinemas and studios! 86 dB is the level that is the standard level used when calibrating movie houses, for various reasons. The only drawback with doing the initial test at 86 dBC, is that some of the modes might be so strong that they drive the system into clipping, or distortion... which REW will detect, and warn you about anyway. If that happens, then you might need to turn the level down a little to do those initial test, then turn it back up again once the initial treatment is in place and the super-powerful modes have been tamed already.

OK, back to Lucio's case: the way those two graphs line up is very clear: all of the axial modes are very clearly present: Most are peaks, but some are nulls. If the mix position is located in a modal null, that frequency will "dip", so to speak, with reference to the surrounding modes.

So the big thing here, is that the room is behaving very much as predicted by theory: that is good! It makes the job of designing treatment easier. However, this isn't always the case: In some rooms, the initial "empty room" baseline test shows discrepancies: the modes do not line up with what theory says. Usually, that is because the construction of the room is interfering: the walls might be very flimsy and thin, with the wall panels themselves getting involved, or there might be resonances in some parts of the room structure but not in others, or symmetry issues, where one wall is solid concrete but the other is drywall with a door and window in it. Or there might "coupling" going on, where the room is not acting all on it's own, but rather the rooms around it are also reacting, adding their own stuff to the response. Or the room might not be "plumb and square": it might be "skew", with the walls not being parallel, or the ceiling slopes a bit, or there's a fireplace or staircase, beams, pillars, niches, built-in wardrobe, etc... It's a lot harder to treat those rooms, because you first need to figure out what the cause of the discrepancy is, then what to do about it.

But in Lucio's case, the room is well isolated, the construction materials are good and solid, and the modal response is quite close to what theory predicts.

That was the "before" situation, for the original long room. Then Lucio built that partition wall across the back, with the door in the middle, so the room length is now 6.30mt..... and now we have this situation:

Once again, the match between prediction and measured is very good. Don't worry too much about the intensity (magnitude, amplitude) of the predicted and measured response: Rather, it's the frequency that matters: Do the frequencies of the measured response line up with those of the predicted response, and do they have the same relationship? Yup, they sure do! There are some differences, but nothing important.

Now, here's the actual predicted and measured frequency response of the shorter room:

Once again, the match is very good (red is the predicted steady-state frequency response, green is the actual measured steady-state frequency response. There's a slight discrepancy in the lowest axial mode, at around 30 Hz: the measured response is a bit higher in frequency and lower in amplitude, which is a good thing!

And finally, a comparison of the waterfall plots for the Long and Short rooms:

Red is the original long room, and green is the shortened room. You can clearly see how the lengthwise axial modes have changed drastically in frequency, with all of them moving up the scale to a higher frequency, but the other modes (width and height) have not changed at all (of course, some of the tangential modes have changes too: the ones associated with length and either width or height).

So, that's where we are right now with Lucio's control room, and the initial analysis, and how the modal response changed when the rear wall was added.

Ain't it wonderful when acoustic reality matches acoustic theory?

- Stuart -

Wow Stuart, it's awesome how close the prediction was! Last week I took some measurements at my temporary studio, at home (until COVID19 allow us going out to work again) and the prediction isn't that close. But I'm amazed how it is in this case! It's a prove that it works.

Cheers,

Eric

ericwisgikl wrote:Wow Stuart, it's awesome how close the prediction was! Last week I took some measurements at my temporary studio, at home (until COVID19 allow us going out to work again) and the prediction isn't that close. But I'm amazed how it is in this case! It's a prove that it works.

There could be many reasons why yours doesn't match, Eric. I mentioned a few of them above, but there's something I should add to that: getting the speaker and mic positions correct in the simulation software is also critical. Its important to measure the locations of each speaker acoustic axis carefully in all three directions, and make sure that the simulator has the correct data. If one of those positions is off, even by a few cm, then the results can be different from what you expect.

Another thing I should add: I did all of the above with just the right speaker by itself: no left. There could be interference patterns between the sound fields from both speakers, and the interaction with the room, and the precise location of the mic, so its best to minimize the possibilities for all those nasties, and just do one speaker. That applies to both the prediction (simulation) and the actual testing. Sure, for a more realistic view of the response for actual room tuning, you need both speakers on at once to check the low-end (or in Lucio's case: all 6 speakers on, in various combinations!), since that guarantees that you are looking at a realistic representation of a typical mixing session, but for these early "baseline" tests, its better to just do one thing at a time.

- Stuart -

Thanks Stuart. As always, getting doubts out!

Lucio, congratulations! You'll end up with an awesome sounding room!

Cheers,

Eric

Really .....
many thanks to Stuart who goes out of his way to explain everything in detail
Specifically, from his comments i understood how to interpret those "abnormal" behaviors of the expected modal response compared to the measured one !! A great lesson, thanks again!

Fortunately Stuart in his reply did not publish the waterfall in full in its decay ...... originally it was more than 2 seconds but, as he had anticipated, it was an almost predictable condition for a completely empty room and without any treatment.

I will update this thread quite frequently as soon as the works begin, we are currently completing the secondary control room for which unfortunately we have not implicated Stuart but for which he has however made himself available to comment on our work, trying not to mess, I'll post the photos as "Control room B"

Thanks also to the pleasant and stimulating comments of each one, we appreciate very much, this is an ambitious project realized entirely by the collaboration of a group of really motivated friends, surely we will imply Stuart also to completely review the "live room" and finally for the largest event room that we will deal with in his treatment later, these are difficult times even in Italy, but we are confident of being able to complete everything in not too long times.

See you soon,

Lucio

Hi everyone!!

A brief update on our progress.
Stuart is completing the layout for our control room "A", he has already sent me a preview, i know he is very busy and therefore let him work quietly.
In the meantime we are completing the acoustic treatment in the control room "B" whose dimensions are listed:

5.62m L
4.00mt W
3.42mt H

For this control room we did not ask Stuart for advice, unfortunately we cannot afford it at the moment, Stuart advised me to publish the progress because i could have benefited from everyone's advice and ..... i like this idea.

The original design is of my own conception .... i obviously take all the responsibilities for better or for worse so .... be merciless

I attach some pictures, some views of the sketch and others that document the current state....in inverse order...sorry
I tried in the design to carefully study the correct inclination of the frontal construction in order to obtain an RFZ in the widest possible listening position, at least for the first reflections. I am still not clear how to properly deal with the acoustic treatment of the rear wall, I have already created a rough structure for the maximum space that we can use even if I am aware that it is quite limited and, bigger problem, the front door turns out to be completely moved to the right looking at the rear wall .... surely some problems will derive from non-symmetry but .... there was no choice
In the front and rear construction, I have provided space to accommodate possible membrane traps (MLV) that could be tuned to problematic frequencies but, to be honest, I will need anyone's help to evaluate the first comparative results with REW. ... it will be a great but conscious challenge, especially with myself
During the week I will document how the broadband traps were made on the side walls, in the meantime I will appreciate any kind of comment, thank you in advance

Lucio

Greetings Lucio,

Congrats on your progress!

In the third photo from the top: are those HVAC ducts in the boxes? If so, it looks like you've coupled the two leaves with the boxes. It may be just the angle of view in the photo. Likewise, the first photo shows your box (more clearly) coupling the leaves. I will of course, defer to Stuart and everyone else who has far more experience, but I think this could be a problem.

All the best,

Paul

Hello Paul,

thanks for your reply and congratulations for your careful observation
In fact it is as you say, the upper box (air inlet) is coupled with the ceiling (the upper part).
I must necessarily specify that the entire wooden frame is not decoupled from leaves, unfortunately the boxes will not be.
I only treated the inside of the boxes with acoustic foam to dampen any resonances, (I hope so) .
The function of these boxes is only to be able to house the vents, the various silencers (baffles) will be installed outside above the ceiling, we have a lot of space above the ceiling of the control room.
Forgive me if I have not been clear, it is really difficult for me to make myself technically understood, I will be happy to put more explanatory pictures if necessary.

All the best

Lucio

Greetings Lucio,

Forgive me if I have not been clear, it is really difficult for me to make myself technically understood

Your explanations are perfectly clear.

All the best,

Paul