John Sayers' Recording Studio Design Forum Archive

Hello to everyone,
Finally after months of reading this forum-treasure and learning, is time to slowly start my own project! As the title describes I have the luck to be able to dedicate a room of my house to create a little home studio. Its dimensions are L: 3,74m W: 2,91m H:2,50m and is part of an old 50's house built of 70cm stone outside walls, 25cm solid brick inside walls, concrete tile floor, concrete ceiling and a solid wood 3cm door. The house is ground floor and there is another residence above.
I already have done some work in Sketchup and put some ideas in you can play with, which you can find in the following link:
https://mega.nz/file/F5kDELja#djt8Px0qH ... xU01IHJMNk
Here is the empty room sketch: And here is a photo of how it actually is: I also have done the proper preliminary homework:
https://amcoustics.com/tools/amroc?l=37 ... ing%20room
and have also done some REW measurements, BUT with the room as seen in the picture (semi-empty that is..) so I don't really know if there is any point of posting them right now..

The heavy wall construction has already given good isolation from/to the outside world (nearest neighbour @ 4-5m.. ) with the weak link be the double-glazed window measuring 35-something db Loss just outside of it. I don't usually work with high SPLs, but there are dogs barking in the neighbourhood and airplanes frequently passing so I have to take care of this.
I also have to take care of the inside door isolation, the room is IN the house me working is annoying to the others, as you can imagine..

The purpose of the room mainly is to be the best control room it can be according to its size, and also to have the ability to make a decent recording in it, mostly spoken voice.
Things that I must do:
1) do something with HVAC. Since it is just a single room I think is will be relatively easy, but still I am searching and learning.
2) make a super-door to isolate from the rest of the house
3) decide how I must treat the room to have a good sonic result with the minimum space consumed.

The biggest problem of all is the budget. I work as a sound engineer in the live industry and as you can imagine with the covid situation most works have stalled and I have no stable income, so the choices will be made with this in mind.
Thanks for reading!

Wow, that is one difficult room. Massive walls and small size will lead to very strong modes, with low modal density.
I would recommend:-
A Cloud as big and thick as you can manage. Even a suspended ceiling over the whole room.
Treat your Back Wall (behind you) as thickly as you can. You could do the same on the Front Wall, with the speakers sunk into the treatment perhaps.
Side wall reflection absorbers of course.
Thick fibre absorption is very effective and luckily it works best with low density cheap fibre.
Another ray of sunshine, the acoustics needed for mixing are the same as for clear vocal recording.

Greetings,

As you prepare your padded cell,

1) do something with HVAC.

.

Given the amount of absorption you'll need (follow DanDan's suggestions!), your room will get stuffier, in both senses of the word. As a voice artist, you know how important breathing is, so you'll really need to sort this out sooner rather than later. If you are able to remove the window, you could frame in the space and use it for a mini split and ventilator. Your gear will also thank you for addressing this.

All the best,

Paul

Thanks both of you for your comments. I am currently converting the simple door to something more usable by adding a layer of 5mm mlv 10kg/m2 and an extra 30mm mdf layer.
I am also searching about the ventilation and a question has came up: where I live we have mild winters (5-15 Celsius) and hot summers (30-35 Celsius). Is the Hrv an one-way solution or a simpler system would do?
Thanks again..

Dio wrote: And here is a photo of how it actually is:

IMG_1587.jpeg

sorry for offtopic: are those speakers diy/based on something etc?

anodivirta wrote: sorry for offtopic: are those speakers diy/based on something etc?

Yes they are diy. The 8” woofers are Seas p21rex, the mids are Morel MDM-55 and the tweeters Seas 25tff. They are triamplified, the processor-crossover is a Void Acoustics Digidrive+ (rebranded Xilica DCP-3060), the amps are two Linn LK85’s (low and mids) and a Linn knekt roomamp (tweeters). The box is built with the assistance of the BassBox Pro software.
The idea, the time of making, was to make a “poor man’s ATC” ,if possible..

Happy new Coronavirus quarantine everybody!
I finally finished my door and while I am still perfecting the seals the results are within expectations. Here is pink noise playing in the room (blue) and the result just outside the door (purple). Note that I didn't make a super-heavy door because the house is quite old and I didn't want any surprises with cracked jambs etc...

After done that, I am happy to post my baseline mdat which you can find here:
https://mega.nz/file/RkMxSYJL#KDEZxVp4F ... YGovxWhF1I

and some screenshots: Keep in mind that the room was not completely empty while measuring, there was a small drawer and cabinet in, things that will remain in place anyway.

Below is what I have in mind doing for this room:
60cm of hanger at the back wall 20cm insulation on the door , 20cm insulation +10cm air gap in the "refection zone", 30cm absorptive ceiling, angled slats at the back half of the room (to keep some life where the recordings would happen) and flushed monitors with slot resonators in the lower and upper section of the speakerwall (an idea that came after seeng the results of this build http://johnlsayers.com/phpBB2/viewtopic ... &start=165), and maybe a limp mass absorber between the monitors for that 45hz mode..
spk file: https://mega.nz/file/toNDzYDR#dStoxAiAt ... OucFlO0ee0

What is your opinion on this?

And lastly the hvac part. A mini-split will take care of the air-conditioning and a small fan (I believe this https://www.solerpalau.com/en-en/in-lin ... 0v50hz-re/ will do) the ventilation. Since my walls are one leaf (and because of the lack of space) I will use one silencer for the fresh and one for the stale air.
Calculations:
Three people max 25x3=75m3
To obtain the 1,5m/s speed I need 13,3cm diameter register or almost 140cm2. I plan to use 10cm pipe and at the last meter 16cm (200cm2) with a 10x30 (300cm2) output (or whatever dimensions close to that). Will this work?
For the silencers I triple the cross section area (from 100cm2 to over 340cm2) and add one more baffle to the Gregwor design.
I will be happy to read your comments and suggestions!

Hello to all,
One alternative layout I am thinking about is this: with soffit wings extended the more I could extend them, letting more room free with the cost of less absorption on the side walls.
It has a quite good raytrace image too. What do you think?

Wandering around in the forum I found these topics:

http://johnlsayers.com/phpBB2/viewtopic ... p&start=15
http://johnlsayers.com/phpBB2/viewtopic.php?f=1&t=14201

their rooms are almost identical in dimensions to mine, and also John Sayers himself has given some skp files, so I gave it a try: The first one seems nice and doesn't consume much space but its raytracing is not what one could expect. Since these "walls" are slot resonators is there any meaning in raytracing? Am I missing something here?
The second maybe is more promising, are there any serious disadvantages is the "sawtooth" design?

Thanks,
dio

Happy new year to everyone, and a wish to try and make 2021 a better year.
Small room-big update for the beginning of the new year: I finished the back wall hangers and I think regarding their size it was a success.
I used Knauf Ultracoustic insulation (5kPas/m²) 100mm on walls/50mm on hangers and 200mm above the door. The hangers core is 4mm mdf, the choice of which was a result of the simplistic thinking that a 4mm thick 750kg/㎥ mdf surface would have closely the weight of a 12mm thick 440kg/㎥ Homasote same surface. Also I cannot find any Homasote where I live, mdf is everywhere.
Measurements following:
Waterfall, first with the hangers and then the empty room for reference Spectrogram, first with the hangers, then the empty room for reference Impulse response, hangers RT60, Hangers RT60 Hangers-empty room comparison Frequency response, hangers mdat:
https://mega.nz/file/5stk1Z7I#OWIR4HuH8 ... 0aSscH-gzY


To my -untrained- eye the installation seems successful. By looking the RT comparison alone we can see that the rt has reduced to half, even in the very low frequencies below 80hz. Spectrograms are another fun graphs to watch: all that spikes below 400hz are greatly damped, even that 45hz monster. One can notice that in the hangers version that mode has shifted to 42hz, because travelling in insulation the speed of sound is reduced and it takes more time to make that 60cm to the wall, so it "thinks" is a bigger room.
The rest of the spectrum is nicely ironed as well.
Same applies to the waterfalls: all those long modal "legs" in time are beautifully shortened with that 89hz almost disappeared, something visible in the frequency response also.
Would using homasote or fibreboard produce better results? Who knows ? What are your comments?
Next step, door treatment and HVAC!

Dio

looks great! yeah, you might see some difference with a lower density panel but the results are promising.

Thanks Glenn!

Hangers definitively are effective. For comparison see a triple graph below: baseline-wall insulation without the hangers-final construction.
It is clear that the hangers do their job below 150hz By seeing the effect the deep speakerwall slot resonators had in this built http://johnlsayers.com/phpBB2/viewtopic ... &start=150
I am convinced to take the same route: to tame this 42hz monster.
Acoustic modelling gives this prediction (from-to) for my tight soffit dimensions: Since I won’t have a large desk (the one showing is temporary), back reflections from it will not be a problem I believe..

Dio

Happy New Year y'all. Watching Dio, keep up the great work.

Thanks DanDan! It's nice to hear encouraging words!

Dio

Looking great! Any updates?

What width are each of the rear hangars? and what depth is the total rear frame?