John Sayers' Recording Studio Design Forum Archive

Alrighty then ... finally able to get some noise measurements.

Here's what we got.

In the basement, I set up monitors for the test. For the source music, I used the track 'Liberian Girl' from MJ. [nice deep bass & transients - also a particular track that prominent 'others' would not object to] !!

When listening upstairs in the living room,
the 'barely perceptible' sound level measured 69 dB at the source [meter 3' from speakers].

Turning the source UP to ~73 it was 'somewhat' ok upstairs.

Source @ 83dB was 50dB upstairs
Source @ 90dB was 57dB upstairs.

These are ~ average levels taken 'SLOW' with C-weighting measured 3' from source.

In general, I tend to work ~ 83dB. Sometimes stronger, many times lower.

I'm sure there'll be specific questions as to what target to go for. Given the height restrictions of the basement ceiling, there may need a compromise ... not sure.

It would be wonderful to be able to work uninhibited, day or night, without disturbing the household. How aligned with reality would be curious to say the least.

Anyway, I sincerely hope I've been able to provide useful data ... please let me know !

And THANKS for all your kind guidance and insight.

Sincerely,

RJHollins

Well, you can draw some rough conclusions, then, based on those rough numbers.

It seems like "'barely perceptible" must have been somewhere in the region of 40 dB, which is pretty quiet. That would put "somewhat ok" at around 45. So your goal is that you want somewhere between "'barely perceptible" and "somewhat ok" as the highest level upstairs? Meaning around 40 to 45, while you are playing your loudest downstairs? Is that a reasonable summary?

You also say that you mix at around 83 db, "sometimes higher". It's the "sometimes higher" that will be the issue. Let's call it 90 dB, for argument's sake.

So now you have a rough goal: How loud are you? 90 dB. How quite do you need to be? 40 to 45 dB. How much isolation do you need? About 50 dB. How much do you have now? Less than 30 dB.

Cool! You have a design goal! You need at least 20 dB more than you have now, or a total of about 50 dB. The good news is that 50 dB of isolation is do-able. The bad news is that it is going to eat up some height, and you don't have much height to play with. The good news is that there are some techniques that you can use to minimize the height loss.

You might want to take a look at IR-169, IR-766 and IR-811 to get an idea about what kind of isolation you will need for the floor above you, that will get at least 50 dB of isolation. Those give you real laboratory test results and objective analysis for literally dozens of possible floor structures, so you can see which one most closely fits what you already have, and what you need to do.

Of course, this isn't just about the floor: your walls, windows and doors will also need to be designed for 50 dB of isolation. But your floor is the priority, due to the tough height limitation.

Progress!


- Stuart -

Ahhh Stuart ..... THANK-YOU.

This has been some of the best news I've received in quite some time.

All the issues/concerns of importants you have nailed.

From all the reading I've been doing here on the forum, I am now keenly aware that the ceiling height poses the most concern. Being of the 6'2" persuasion, the 'bare-naked' ceiling [floor joist] above is already a limiting factor ... but without the desired isolation, the build would be 'just another room in the house', and I would have wasted BOTH of our time.

In your post, you mentioned 'IR-169, IR-766 and IR-811' ... forgive my ignorance, but where might these be ?? I'd very much would like to study this so that I can be as informed and helpful to YOU

As always ... I look forward to your replies.... and THANK-YOU.

Sincerely,
RJHollins

RJHollins wrote:In your post, you mentioned 'IR-169, IR-766 and IR-811' ... forgive my ignorance, but where might these be ?? I'd very much would like to study this so that I can be as informed and helpful to YOU

Stuart is great.

RR-169
IR-766
IR-811

And just for fun:


RR-193
RR-168
RR-193
IR-802

That should give you some reading material for the evening.

Andre

Hello Avare,

I have been reading/following the other design & build threads on this forum. I find that you provide of wealth of information & insight. Others, as well as myself, are fortunate for the education you share with us. THANK-YOU.

And thanks for the links to the articles referenced by Stuart. I feel very privileged to have his knowledge and experience directing/educating me in this critical mission.

I hope I can at least gleam some sense of understanding of those tech papers.

Coffee is on ... onto the reading. [which I'll mix another absorber cage, or two, build in with].

Onto the homework assignment

I've been reading through the posted .PDF files ... very exciting stuff
No, really ... some very pertinent, technical information. There were several sections of information that were surprising in the test results & conclusions. In fact, some aspects confirm what I would now view as 'un-informed' design/implementation error of studios I've been in that where not of the 'Class-A' design ... even though they may have been nicely decorated. This is quite enlightening.

Speaking of which ... having been sitting now for a couple of weeks in a basement that sonically now resembles a 'factory gymnasium', I decided tonite was the time to test load my aluminum cages with 2 sheets of 2"x2x4'.

Although I did not apply the final rivets to lock the top and bottom sections together, the panels fit just as I had hoped.

What was real nice when I carried one down from the garage into the basement, the immediate awareness of that acoustic absorber just leaning against the concrete wall. Of course, this immediately led to the loading up of another cage! hmmmm. Well, since the bag of 2" had 10 sheets ... I loaded up 5 cages.

They are just leaning up against the wall ... but I gotta say ... just those 5 loaded cages have altered the sound of the entire basement Sure, I can hear the other walls, and the scattering of the joists, but the impact was immediate and significant

It doesn't mean much at this point ... other than typing this message is not the mind jarring distraction it was just moments before doing this.

Anyway ... just had to mention this ... and post a quick pic.

ok ... ok ... back to my reading assignment.

RJHollins wrote:I've been reading through the posted .PDF files ... very exciting stuff
No, really ... some very pertinent, technical information. There were several sections of information that were surprising in the test results & conclusions. In fact, some aspects confirm what I would now view as 'un-informed' design/implementation error of studios I've been in that where not of the 'Class-A' design ... even though they may have been nicely decorated. This is quite enlightening.

Welcome to the world of acoustics and congratulations on getting past the first hurdle! The biggest problem in beginning to be student of acoustics is that almost nothing is intuitive and to learn to seek test verification when ever possible. Accomplished studio designers will recommend/design almost nothing that is either not tested or not well within the bounds of acoustical physics.

If there is one constant in my life as a student of acoustics it is that the more I learn, the more realize how little I know.

Andre

Thank-you Andre.

The words you speak seem to ring true for so many things in life.


With all the activities today ... I managed to assemble and load 5 more panels.

Stopped out at Jo-Ann's Fabrics today. Looking at the 4oz poly-batting as an under-covering, and some of the burlap fabric choices for the final.

Seeing that the fabric requirements are limited ... I wondered if some type of image could be painted on the panel ... some type of musical artwork is what I thought.

The image would not have to be photographic ... thinking more impressionistic [of course, still maintaining the open acoustics of the burlap fabric.

Anyone try anything like that? Any suggestions/ideas ... things to NOT do ???

Thanks !!

You may find this thread of value.

Andre

"things to NOT do ???"

Don't clog up the fabric with paint lest it not be able to breath correctly

Thanks Gentlemen,

This is why I asked !

So I'm guessing that covering the panels with 4oz batting, and then a burlap finish is the most I should do then ?

Thanks!

the link Andre provided mentions "dye sublimation" which shouldn't impact the acoustic property and allows plenty of design options... although there have been discussions here and studiotips about painting fabric as not being particularly harmful...

Talking with one of my 'resident fabric experts', she was wondering if the burlap fabric could be velcro'd on the back of the aluminum frames?

That way, the 'covers' could be cleaned, they could be changed out for a different color, or they could be 'artistically treated' at a later time.

I like the idea, but am concerned that the 'fit' may not be as 'clean'. I have no idea how burlap is to work with, especially any type of fraying, etc.

Those dye-sub'd panels are exactly what I'm thinking !!! But I wonder ? WHAT type of cover material were they using ?????!!!!

Am I stuck using only burlap?? If NOT ... what is the name of other fabrics I could use?

Thanks

muslin is usable, quite a number of wool/yarn type fabrics. i think Bob Golds site may have a list of fabrics on it with approximate (or accurate) flow resistivity etc.

the velcro could be an option but the fiberglass/mineral wool fibers could be a problem in the wash unless the insulation is wrapped in a very fine plastic cover to keep them enclosed. of course there are recycled cotton and hemp insulation which does not have the fiber concerns but costs are typically higher.

"Am I stuck using only burlap?? If NOT ... what is the name of other fabrics I could use?"


It isn't the material so much as it is the process. The process uses "dye" not paint, so there is your crossroad. Paint will clog up the pores and become reflective. Like Glenn mentioned, painting may not be as harmful as someone else might suggest but the scope of the project, the saturation of the picture, may negate some of the qualities of the absorber that may be needed in your environment.

Treatments are installed after the requirements have been established. Painting the treatments has to be either part of the scope or has to be taken into consideration in how the process >used< will affect the response of the treatment.