Drum rehearsal/recording basement studio in Madrid

That sounds like a pretty good deal!

Yeah! I'm actually quite surprised. Based on my window (or wood) shopping I've done these days, typical price seems to be around 80Eur for that material in that thickness.

Depending on what your isolation needs are, you could probably get by with just that as the base layer on your framing, then a single layer of 16mm drywall on top. Likely, that will be enough.

That's also very good news. I'm hoping that even without any drywall on top we could get good results, and just put the MDF up over some framing. Depending on how I go about it, the MDF might be thick enough to stand without needing studs. Guess I'll have to give it a go and see! Also, today I had an HVAC tech come take a look at the space and see what he recommends. I don't think he's worked with airtight rooms before, as he looked kind of confused with the whole idea and he kept mentioning what sounded to me like a lot of unnecessary equipment to get a proper result. Either that or probably I wasn't making myself clear haha. For those following this thread: the plan is to start putting up the walls in early August. Will keep you all posted!

vdegou wrote:

That sounds like a pretty good deal!

Yeah! I'm actually quite surprised. Based on my window (or wood) shopping I've done these days, typical price seems to be around 80Eur for that material in that thickness.

Depending on what your isolation needs are, you could probably get by with just that as the base layer on your framing, then a single layer of 16mm drywall on top. Likely, that will be enough.

That's also very good news. I'm hoping that even without any drywall on top we could get good results, and just put the MDF up over some framing. Depending on how I go about it, the MDF might be thick enough to stand without needing studs. Guess I'll have to give it a go and see! Also, today I had an HVAC tech come take a look at the space and see what he recommends. I don't think he's worked with airtight rooms before, as he looked kind of confused with the whole idea and he kept mentioning what sounded to me like a lot of unnecessary equipment to get a proper result. Either that or probably I wasn't making myself clear haha. For those following this thread: the plan is to start putting up the walls in early August. Will keep you all posted!

Hi there! Just a quick note. Mdf is not structural board. So you can't support a ceiling or door frame etc on it. You will still need your timber framing :D. You will notice that Mdf is very easy to bend compared to structural board like OSB and plywood. Also mdf becomes like cardboard when wet. It will be a good material for beefing up your walls though! Dan

Just a quick note. Mdf is not structural board. So you can't support a ceiling or door frame etc on it. You will still need your timber framing :D. You will notice that Mdf is very easy to bend compared to structural board like OSB and plywood. Also mdf becomes like cardboard when wet.

Hey! Thanks for the input :) Yeah, in the end the timber framing will be necessary. I'm actually designing for it right now taking into account the dimensions of studs that I can find in my local hardware store. I'm not sure how easily this MDF will bend though, noting that it's quite thick at 3cm and won't stand too tall (about 190cm tall). But yes! For sure these will have to be supported on the studs. I'll put up some Sketchup models of the framing design soon once I've completed it. Thanks for checking in!

Soundman2020 wrote:

but I've got some studio monitors that I can borrow. Probably not ideal, but it's something for a first iteration

If they can put out somewhere around 115 dBC, and they have reasonably good bass extension (to about 35 Hz or so), then that should work fine.

PS: Also picked up Rod Gervais' Studio Construction book. Gotta get educated too if we're going to do this right!

Also get "Master Handbook of Acoustics" by F. Alton Everest. Very useful. - Stuart -

What is your ceiling made of? Concrete? If it is sheet rock, I'd suggest removing the sheet rock so that your ceiling is taller (acoustically). You'd then just have to add mass to the underside of the subfloor. If it's concrete, that sucks in terms of acoustic height, but it's good for surface density! [PROBABLE SPAMMER ALERT - TYPICAL BEHAVIOUR.... - MODERATOR]

Just a quick note. Mdf is not structural board. So you can't support a ceiling or door frame etc on it. You will still need your timber framing :D. You will notice that Mdf is very easy to bend compared to structural board like OSB and plywood. Also mdf becomes like cardboard when wet.

You're right! I found that out after trying to find a way to support the MDF without any additional supports, which was a very silly idea. So I have framing in my mind now and the design is almost in place. I apologize for the disappearance, but I am back! The MDF has finally arrived, and now I must wait for the framing material as well as make up my mind on what product to go for with regards to sheathing. This is where my next question stems. Regarding the material to sheath the walls, the most widely available one in my country is rockwool, however I can't seem to find a consensus on what's better: higher density or higher GFR. Apparently there is a slight correlation between density and GFR, although not strictly linear, and a high GFR is desirable. But even then, I've read some posts stating that it's best to stick with 50kg/m3 for rockwool (or along those lines) even though there is rockwool with higher densities and higher GFR. That part is a bit confusing. So, my question is, should I strictly go for the highest GFR rockwool? Will this help to absorb both low and high frequencies? I've compiled some of the materials that are available to me in a table to easily compare their densities, GFR, and total price, but as I'm not 100% sure whether highest GFR should be the goal, I'm a bit stuck. Hopefully someone can chime in here! If I were to choose based only on GFR, I would go for the Alpharock 225 product with a density of 70kg/m^3 and a GFR of >20. I've also read it is good to vary the densities of the sheathing as it might better absorb a different range of frequencies. I've got two leaves to put sheathing on top of here, so it could be possible to do this. Is it a good idea though? As always, I appreciate any help!

Hi there, With regards to the Rockwool, is it for within the MSM walls or within the room for acoustic treatments you're asking about? Within your MSM walls go for low density, low GFR. Anything around 5000KPa*s/m2 is good. If you're taking about acoustic treatments, you should tailor the density/GFR depending on requirements. Deep low density affects lower frequencies and is generally the best, if you can fit it in the room. Use this acoustic absorber calculator to estimate the affected frequencies: Absorber calculator Dan

Hey Dan! Thanks for giving some input.

With regards to the Rockwool, is it for within the MSM walls or within the room for acoustic treatments you're asking about?

This Rockwool is for within the MSM walls.

Within your MSM walls go for low density, low GFR. Anything around 5000KPa*s/m2 is good.

Deep low density affects lower frequencies and is generally the best, if you can fit it in the room.

So what's the logic behind this? Also, when you say "if you can fit it in the room"... how deep are we talking? I only have about 10cm between each of the leafs in the MSM wall, and I thought I'd do something along the lines of 4cm Rockwool, 2cm air cavity, 4cm Rockwool. Would this be enough depth to go for low density and low GFR and still perform better than high density high GFR for reducing low frequencies? Before going deeper into that question, I've used the calculator link you have provided (thanks btw, great tool!) and obtained these results: It seems that the Alpharock 225 product performs best at lower frequencies, while Rocksol and Rockalm are similar and better at the higher end. Since I'll be playing drums and there will be plenty of low frequency involved (kick drum), it might make sense to go for the Alpharock 225. What do you think? Here's the link to the parameters I used in case anyone is curious: http://www.acousticmodelling.com/mlink. ... &v44=20000

vdegou wrote:

So what's the logic behind this?

Within an MSM wall you don't need to calculate frequencies. The absorber is not exposed to the room, you're not going to get isolation via absorption. You gain isolation by mass and damping. MSM stands for mass - spring - mass. Mass is your plasterboard / concrete /wooden surface. The spring is your cavity. The second mass is your second leaf of plasterboard etc. This cavity must be damped, in the same way placing a blanket in a bass drum damps the sound. Completely (yes completely) fill the cavity with insulation (no empty airgaps). The only reason you would have an airgap, would be because you accidentally bought too dense insulation and need to avoid creating a flanking path. The research tells us (sorry I can't find the link to the paper, maybe someone will find it) that the very best isolation is achieved by having the cavity completely filled from surface to surface with low density insulation, the same sort of thing you would put in a loft/attic. Only use the absorber calculator for internal acoustic treatments. It's only useful when the absorber is exposed to the room.

vdegou wrote:

I only have about 10cm between each of the leafs in the MSM wall, and I thought I'd do something along the lines of 4cm Rockwool, 2cm air cavity, 4cm Rockwool

Have your calculated whether that will give you enough isolation? Drums are ridiculously hard to isolate against. You have massive sound energy at low frequencies. How much mass are you attaching to each leaf? Dan

Within an MSM wall you don't need to calculate frequencies. The absorber is not exposed to the room, you're not going to get isolation via absorption.

Only use the absorber calculator for internal acoustic treatments. It's only useful when the absorber is exposed to the room.

Oh, I didn't know that! That's very good to know Dan, thank you for that insight.

This cavity must be damped, in the same way placing a blanket in a bass drum damps the sound. Completely (yes completely) fill the cavity with insulation (no empty airgaps). The only reason you would have an airgap, would be because you accidentally bought too dense insulation and need to avoid creating a flanking path.

Makes sense. This advice regarding damping came just in time. I was about to shell out an unnecessary amount of money for high density rockwool. In the end, I went with the lowest density/cheapest I could find at my local hardware store, and good thing too, because I ended up drastically underestimating the amount I would need. Due to some irregularities in the original room construction (roof isn't completely parallel to the floor, walls are not perpendicular to floor/ceiling at certain points, which make them bulge out and cave in at some points), I ended up having to fill up a lot more than the original 60m^2 of surface area I had estimated.

How much mass are you attaching to each leaf?

The outer leaves are mostly made up of concrete foundation. I'm not sure of the thickness, so unfortunately I wasn't able to get a proper density value from there, but the inner leaves which I do have control over are made up of 3cm thick MDF boards, which are quite dense sitting at around 700-800kg/m^3. I'll post some update pictures in a few minutes, as I am about 90% done with the assembly :) Thanks again for you insight Dan, seriously! You saved me a lot of money on damping!

Hello all! After a long two weeks of work and a lot of help from my father with the actual build, we are pretty much done with the assembly. For having close to no previous experience with DIY, construction, and woodworking, we are pretty excited with the results! I'll attach some pictures to this post for those of you who have been keeping an eye on this build. Also, thank you everyone who commented! All of this information has been of massive use to this project. Without further ado, a very quick glimpse of the build process: Along the way there were some big changes in the design. For example, we decided to leave one of the water pipes inside of the studio and box it up, unlike the original idea of leaving it completely outside. The studio definitely has more space with the pipe inside, but now we have that awkward shelf across the length of it. No big deal, really, although it was one of the most challenging parts of the build. I have to go back in and try to improve on some mistakes where we couldn't get the boards to align 100% with each other. Lots of filler, sanding, and patience should do the trick. Also, this wouldn't make much sense without the data to accompany it! (Note: I got a better sound level meter and retook the base measurements, so they are not the same as the previous ones in this thread) Since the door is still not ready, I simulated one by temporarily covering the place where it would go with the same MDF boards I used for the walls. I hope to put together a timelapse of the whole build, but there is still lots to go. I need to finish covering up some sections of the shelf, correct for any mistakes, paint, and then treat the acoustics. Hope you enjoyed!

:yahoo: Greg