Home production studio in my basement

[HalvorB]

Hi all, gonna build a small studio in my basement for production of UK hardhouse music (maybe some house and techno crossovers). So no live room. The room I've got for the purpose is at the end of my basement with dimensions 5.49 m x 4.38 m x 2.4 m before floor, walls etc are done. Ceiling of wood is already there so that's about the only thing I can't do much with. I will post pics, simulations and overall work progress in this thread and I will also ask questions to all you acoustic wizards out there. Feel free to point me to other threads of interest, I have tried to read lots of threads to find answers before I ask. I have some knowledge of basic acoustics, but not very in-depth.

The room as it is now has not got a door yet (will put in sound insulating door), all walls are the foundation of the house made of something we call blocks of Leca, dunno the right English word for it, maybe ACC (Autoclaved aerated concrete)?

My plan is to build membrane absorbers for the bass and place them basically on all walls floor to ceiling with 60 cm width, then place porous absorbers and insulation outside of those with air in between. I have calculated the total of both membrane and porous absorbers to take up about 20 cm depth shown in figure 1 below. On the back of the back plate for the membrane absorbers should maybe be a heavy airtight, material (building plates of some kind). I will then place thin pieces of hard wood/plastic or other reflective materials in sequences which have even Fourier transformations on top of the absorbers to make Amplitude reflection grating diffusors (ARGD) which will reach very low frequencies and quite high as well (depends how thin I will make the pieces. If I do this on all walls I hope to achieve a very dead room with great diffusion. If this should make it too dead it's easier to make reflectors than it is to dampen the room after it is built is my theory (scream if I'm thinking wrong). My goal is a reverb time of between 0.2-0.25 s throughout all frequencies. I am thinking of ARGD before RPGD because they won't steal more volume from the room.

I have not worked with fibre glass before and dunno how to build membrane absorbers with it. I am fairly good with wood and carpentry. Was thinking of using 3mm plywood for the membrane. Any suggestions re design and making of these are appreciated.

Now, I measured the room today using WinMLS and sine sweep of 20 s to see what I'm dealing with. It is not an accurate measurement as I did not have a omni directional speaker, but it should hopefully be a starting point. As mentioned I do not have a door in and there is also some junk laying around the room still. First impression is that I could move my gear in at once, because the reverb time looks very good. But this will probably change when I put plates up against the foundation. I suspect the foundation cannot be viewed as a solid surface because of the air pockets in it and so it releases the bass outside and this is why I don't have a large bass boost in my measurements. Any other views on this? Anyway, I don't think I should think less of bass absorbers because of this measurement. I would rather turn my speakers up and put some reflectors in rather than having to put bass absorbers on after the walls are finished.

So, this is my starting point, I will pull power cables myself, will put a conduit with 10 x 3 way schuko outlets on the front wall and the side wall with my DJ-equipment. Will use 2 separate circuits, each with 230 V 16 A. I cannot pull my listening position and speakers further away from the wall because the room will also be used by others, will put a coach in front of the back wall for relaxing, listening and will probably be put an electric piano somewhere so my sister can play.

Now, time to show some pics and drawings. Just quickly sketched up a plan drawing of the room in AutoCAD.


Figure 1.





















More pics to follow in next post...

[HalvorB]

Sorry, double post...

[HalvorB]

Mean of 10 measurements of RT60.








So there it is, lots of pics, some graphs, layout of room etc. I will keep this thread updated throughout this summer, but I am working a lot so can't promise you a fast progress. However, any comments from you all are appreciated. Especially regarding building of membrane absorbers for bass.

Halvor

[Colonel Blues]

C'mon my friend, let's get started !!!

[HalvorB]

The room is cleaned out now, nothing left. Making the floor is next step. Working away from home though so next update will probably be in a couple of weeks.

[AnthonyRochester]

you know the waterfall graph (3D Energy, Time, Frequency) is most useful only up to around 300Hz. It might be worth doing another one zoomed in a bit and with more resolution to see a bit better..

[HalvorB]

Cheers, I'll do that next time. However, the results were not accurate in any way since I didn't have an omni directional speaker so no need to look at the details yet. Was just to have a general idea and see if I could point out some serious problem frequencies already from the start. Starting in a new job the end of summer and then I will have access to such a speaker so I can do some more accurate measurements

[AnthonyRochester]

You don't need an amnidirectional speaker, perhaps you meant omnidirectional mic? You basically need to have your speakers set up how they will be for mixing, and have the mic where your head will be when mixing.. The frequency response of the room will vary according to where the speakers are and where you are measuring from, but the main measurement that really matters is for your mixing position.

[AnthonyRochester]

*Omnidirectional

[AnthonyRochester]

Oh, and for low frequencies, most speakers are pretty omnidirectional.

[HalvorB]

Well, yes I know that. Had an omni measurement mic of course. And yes, when all is set up and ready I can measure in the mix position from the monitors, but for measuring the accurate room response by itself I need an omni speaker. To excite all the modes in the room together. The measurement shown is a mean of 10 measurements where I moved the mic around the room and also moved the speaker. When I clap in the room however I can hear a ringing that I didn't capture on any of the measurements, but I would have if I had an omni speaker. I have studied some acoustics and did my BSc with a task on reverb times in concert halls and rehearsal rooms meant for amplified rhythmic music (rock basically). Measured quite a lot of rooms and improved two of them, but that was with a much bigger budget

[MidasHatesGold]

why would you need that??? can you explain. thanx

[HalvorB]

Originally Posted by MidasHatesGold

why would you need that??? can you explain. thanx

Not such speakers... Look at these:

Nor275 Loudspeaker | Norsonic.com

Nor276 Dodecahedron Loudspeaker | Norsonic.com

To comply with ISO 140-4 Annex A standard for airborne insulation measurements in field and ISO3382 Annex A (Reverberation Time measurements).

[HalvorB]

Finally an update! Did lots of planning, purchases etc lately, but now the work has officially begun. Started the weekend with making the level keepers for the floor (dunno what you call them, but it's what you drag the concrete off at to get the level right) and putting primer on the floor to bind the dust etc. Two days later I had a guy help me doing the rest of the floor. Tomorrow I'm going to pour a very thin liquid floor mass out on the floor to even it out completely. I also put up three conduits for power and network cables. I will use the originally thought out conduits for the power to lights etc, then I will have one circuit for each of the two walls with equipment. This will minimize any ground loops. You can see the fuse locker for my house in the first pic. Also some pics of some good tools that's helping me do the job.

[HalvorB]

[HalvorB]

Finally an update. Actually been working so not had the time to write posts on here, haha. See the latest progress on the pics below. Started building the bassabsorbers, that does take time since I'm custom building each one to fit in between the frames which will form the wall. Got rid of the two pillars and substituted them with an H-beam. Built the small roof over the beam, trying to find a supplier of custom windows to put in there now. Floor has been insulated and just waiting for all the carpentry to finish to I can put the parquet floor down. Door opening has been widened to fit a bigger door. Much easier to carry equipment inside. This was done with my new mean angle grinder also shown on a pic :D Split the pics into three posts so in the next ones I won't write anything, just show the pics.

[HalvorB]

[HalvorB]

[HalvorB]