Hybrid Studio - ground up including Monitors and furniture

[Frans Wessels]

In fact, one of the forum members, Greg, has written a spreadsheet to help you figure that out. I can't find the link right now, but I'll try to post it later.

Here it is!

Gregwor & audiomutt’s MSM Transmission Loss Calculator Version 2.03

Greg

Hello Greg, that's very kind. Thanks for helping me. I will take a look tomorrow, it's 23:53 here so my eyes are telling me to go and have a nap.

Keep you posted.

@ Stuart, I'm looking at a calibrated decibel meter on the internet that's affordable but suits my project.

kind regards, Frans

[Soundman2020]

I'm looking at a calibrated decibel meter on the internet that's affordable but suits my project.

Take a look at that link I gave you, about how to use REW: In it, I mention the characteristics you should be looking for in a sound level meter, plus a few brands and models that I have found to be good at reasonable prices... Here it is again: http://www.johnlsayers.com/phpBB2/viewt ... =3&t=21122 .

- Stuart -

[Frans Wessels]

Take a look at that link I gave you, about how to use REW: In it, I mention the characteristics you should be looking for in a sound level meter, plus a few brands and models that I have found to be good at reasonable prices... Here it is again: http://www.johnlsayers.com/phpBB2/viewt ... =3&t=21122 .

- Stuart -

Hi Stuart,

Yes, I'm looking into that. I've learned more this week than in the past few year on the internet. So as you stated, I'm on the right forum here to ge me a control room.

Seems like a good usable sound level meter comes at 100 - 200 euro's, which is OK by me. It is an important tool for the preparation and actual build. Not sure about the mike I use on REW, it is most likely the the Behringer I'll check on that.

Kind regards, Frans

[Frans Wessels]

Using Gregwor's TL calculation excel sheet the wall as drawn in the picture below shows nice results.

The first picture shows how I put it in.

@Stuart / Grewor : IS THIS THE CORRECT WAY?

The STC63 (NEVER MIND THE TITLE, it's WRONG as per comments of Stuart) is the principle wall with 5" space between the 2 walls. The TL graph show some 60 dB transmission loss, which is close to what may be needed. So the system contains Brickwall outside & Gypsum wall inside.

NOTE: I need to do the measuring as described in the previous posts, but this is giving a first impression on the TL (Transmission Loss) of the system (the 2 walls). From 160 Hz down It falls short (becomes more audible outside).

kind regards, Frans

[Gregwor]

Grewor : IS THIS THE CORRECT WAY?

No.

You need to know the depth of your brick and you would enter the rest like this:

Missing Brick Depth.png

You would enter the brick depth in the box below Leaf 2 Support Structure Material where it is labeled custom depth value.

If you want to see the difference the OSB would make, add it into Leaf Sheathing 1 Material 3.

Greg

[Frans Wessels]

Grewor : IS THIS THE CORRECT WAY?

No.

You would enter the brick depth in the box below Leaf 2 Support Structure Material where it is labeled custom depth value.

If you want to see the difference the OSB would make, add it into Leaf Sheathing 1 Material 3.

Greg

Hi Greg,

AAAhaah, NOW I see how it works, makes sense.

So this is how it looks like with the excel sheet used the correct way. Which is almost overkill.

Assuming I would mix at 80 - 90 dB levels most of the time, OUTSIDE levels would be 28 dB at 20 Hz as the loudest and 24 to 5 dB from 30 Hz upwards. The OSB does not add much, it has low mass and I opted for ½ inch thickness to cut on price. It is only intended to be a handy background to screw Gypsum on (does not matter WHERE I want to put a screw).

This combination of a brick wall and a double Gypsum wall works very effective. I could even improve a few dB with 1 Gypsum layer of ½ " and 1 layer of ⅝ ". Would be more expensive and I'm not shure I NEED it.

I also checked with wood studs, which seem NOT to work at the low frequencies. Wonder why a LOT of studio are build with wood framing. Also on price, steel is more cost effective.

Did I miss something here?????

kind regards, Frans

[Gregwor]

I also checked with wood studs, which seem NOT to work at the low frequencies.

Did I miss something here?????

What happened for you to state that wood framing doesn't work at low frequencies?

The calculator does not change results based on steel vs wood. Basically, the way it works is that it adds the depth of the wood or steel framing to the gap that you enter. The formulas main variables are surface density (that's why you choose your sheathing) and the distance between the sheathing (an addition of the framing and the gap you enter ---- unless you choose brick, concrete or inside out support structure material).

The model of steel framing you choose obviously affects how deep the framing is, no differently than choosing different sizes of dimensional lumber for your wood framing!

Wonder why a LOT of studio are build with wood framing. Also on price, steel is more cost effective.

Wood is a lot easier to work with, it is much stronger and more rigid. It is also a lot cheaper in some areas of the world.

Greg

[Frans Wessels]

What happened for you to state that wood framing doesn't work at low frequencies?

Hi Greg,

Let me rephrase that, When using wood as support structure, TL was less at low frequencies as opposed to steel framing. Checking what I found by re-applying, seems I made an error by NOT selecting the same (2 x 6) wood frame size. When done correctly, it seems only 0.5 dB better with steel, which is not of great interrest.

I added a version where I only changed the support structure from steel to wood to show what I mean.

Wood is a lot easier to work with, it is much stronger and more rigid. It is also a lot cheaper in some areas of the world.

Greg

Makes sense, in the Netherlands I found steel to be a bit less expensive. I'll do a calculation for the compleet controlroom.

kind regards, Frans

[Gregwor]

When using wood as support structure, TL was less at low frequencies as opposed to steel framing. Checking what I found by re-applying, seems I made an error by NOT selecting the same (2 x 6) wood frame size. When done correctly, it seems only 0.5 dB better with steel, which is not of great interrest.

The difference is caused by dimensional lumber actually NOT being the exact size that it is labeled as.

A 2x6 piece of lumber is actually 5 1/2"

A piece 600s steel frame is actually 6"

So, with the steel, you are actually getting a 1/2" larger overall gap between your sheathing. You could achieve these same results by moving your wood frame over another 1/2".

Greg

[Frans Wessels]

Hi Greg,

Thank you very much for your help AND of course your super spreadsheet. This has given me more information than I found on the internet, where a lot of conflicting "facts" and opinions reside. On the supporting structure, I read that steel is a much better material for the supporting framework (having a higher TL at low frequencies). Using your sheet, seems NOT to be the case if I understood correctly.

kind regards, Frans

[Frans Wessels]

Hi Stuart,

I'm looking at a calibrated decibel meter on the internet that's affordable but suits my project.

Take a look at that link I gave you, about how to use REW: In it, I mention the characteristics you should be looking for in a sound level meter, plus a few brands and models that I have found to be good at reasonable prices... Here it is again: http://www.johnlsayers.com/phpBB2/viewt ... =3&t=21122 .

- Stuart -

I found the ExTech 407730, which is available in the Netherlands and costs 100 Euro's. Does A&C weigthing, 40 - 130 Db range, Fast and Slow response, Max Hold and is calibrated of factory.

QUESTION:
Is this a good dB meter for my project AND calibration of REW? Ofcourse there are others, but I have to make a choice and the more expensive ones have additional options, which I'm not shure I would need.

kind regards , Frans

[Soundman2020]

I found the ExTech 407730,

Yes, that's an excellent meter. One of the ones I recommend.

- Stuart -

[Frans Wessels]

Take a look at that link I gave you, about how to use REW: In it, I mention the characteristics you should be looking for in a sound level meter, plus a few brands and models that I have found to be good at reasonable prices... Here it is again: http://www.johnlsayers.com/phpBB2/viewt ... =3&t=21122 .

Which mic should you buy? I do NOT recommend the Behringer ECM8000 mic for this, as I've heard too many sad stories about people getting faulty mics, including my own personal experience.

- Stuart -

Hi Stuart,

Yes, I'm looking into that. I've learned more this week than in the past few year on the internet. So as you stated, I'm on the right forum here to ge me a control room.

Seems like a good usable sound level meter comes at 100 - 200 euro's, which is OK by me. It is an important tool for the preparation and actual build. Not sure about the mike I use on REW, it is most likely the the Behringer I'll check on that.

Kind regards, Frans

So much for buying the right gear......

Ooh well, I guess that's just life, win some / loose some.

[Gregwor]

So much for buying the right gear......

Ooh well, I guess that's just life, win some / loose some.

I've used that mic with good results. The mic is just famous for being hit or miss. Also, there are a few different calibration files floating around the internet for it. And it's basically impossible to know which one is right for your mic. So, I'd suggest using it for everything except frequency response. There's no reason you can't use it for things like RT60 and waterfall plot type measurements!

Greg

[Frans Wessels]

The decibel meter has arrived.

I drew a map of the shed and its surroundings.

A - measuring spot OUTSIDE noise before entering the studio
B - INSIDE noise in studio
C - measuring spot OUSIDE noise for our house at living-room window location.

Now find some time to do measurements. First indication of traffic noise (dBC slow rate) at A is 66 dBC for normal cars driving by at allowed speed (40 miles / 60 km). That's not to bad. I think the earth wall is of much help.