Help with apartment home studio build in Brazil

Hi Guys! I've just moved to a new apartment and there is a spare room I intent to use for my home studio. I am only doing electronic music stuff so all in the box and no mic tracking. I have a pair of Se Munro Egg 150 and also a pair of Event Opals which i will be chossing from. My room is 4x3mx2,5m (LxWxH) The clean layout is as follows: I then hired a local specialist in Brazil and he came up with the following design: Behind the dry-wall we will have rockwool. I have no concerns over isolation, my main concern is treatment. I know building the walls would result in a more isolated room but it is not my primary concern right now. I know the room is kinda small so here comes the questions: - Will I benefit from the splayed walls and angled ceiling within these dimensions? - Would it be best to just treat with panels and traps and leave everything parallel? I am worried I will have high construction costs doing the drywall and in the end it does not really solve potential issues. I had an idea to buy all the panels and put them up in the rectangular room and measure to check for frequency response and then try later, but also I might just be losing precious time. Some renders:

I just realized I posted in the wrong section. Can the admin move or should I delete and post on the correct area?

Here is the room response without any treatment. Any ideas?

Hi Diego, and Welcome! :)

I have a pair of Se Munro Egg 150 and also a pair of Event Opals which i will be chossing from.

I would probably go with the Opals as the mains for that room, and maybe use the Eggs for mix checking. Especially if you decide to soffit mount (highly recommendable!), then the Opals would be the only choice as mains: I doubt it would be easy to soffit-mount Eggs!

I then hired a local specialist in Brazil and he came up with the following design:

It's an interesting design, but does seem to be wasting space, and does not accomplish a true RFZ.

Behind the dry-wall we will have rockwool.

What density? How thick?

- Will I benefit from the splayed walls and angled ceiling within these dimensions?

There is always benefit, but then again, there is always benefit from maximizing room volume, and minimizing modal spread issues. Studio design is all about compromises: finding the best combination of many, many aspects. And it is different for each room. In your case, with a small room like that, I would not drop the ceiling, and I would only angle the parts of the walls that really need it in order to create a true RFZ. I would leave the ceiling at the full height and just hang a suitably designed cloud to deal with both first reflections and modal issues.

- Would it be best to just treat with panels and traps and leave everything parallel?

You will need bass traps and treatment panels anyway, and parallel will maximize room volume. However, there are real benefits that can be obtained from soffit mounting speakers, and also from creating an RFZ type design. I would suggest trying out a few scenarios for doing that, to see if it can be achieved.

I had an idea to buy all the panels and put them up in the rectangular room and measure to check for frequency response and then try later, but also I might just be losing precious time

Designing and building a studio takes a lot of time anyway. Trying out different things is a good idea, provided that you already know what you are doing, and have done the math to predict the outcome: in that case, trying things is to check that they actually do work as designed. But just experimenting by putting different things in different places, to see if something changes, is not a good way to do it.

Some renders:

I see QRD style diffusers in several places, but that room is too small for that type of diffuser: There is no point in that room where you can have a numeric-sequence diffuser more than 3m from the ears of people who are doing critical listening, and that's the basic limitation.

Here is the room response without any treatment.

That's just the full-spectrum frequency-response graph, which isn't very useful. That only tells you a very little bit about the room, and only in the frequency domain. The problems in small rooms are mostly in the time-domain. You have also smoothed that curve way too much, so you are hiding the real issues and possibly making problems appear "shifted" from where they really are. Please post the actual MDAT file, so I can download it and do a more complete analysis. I would also need to know exactly where the speakers and the mics were for that test, which speaker was used, and how the signal path was set up. All I can say from that curve is that the room has major modal problems (to be expected in a small room), there are SBIR issues probably, some type of comb-filtering, and excessive treatment in the high-end: maybe a carpet on the floor? Either that, or you did the test with two speakers at once, and you happened to have the mic in a location where that causes the cancellation in high frequencies, causing the appearance of a roll off in the highs, but it isn't really there for a person sitting listening at the same location. - Stuart -

Hi Soundman2020!! THank you so much for taking the time to reply and help me out. i've done a lot of reading these past few days trying to grasp more information on the matter. I can see it is a very complex and trial and error process to achieve a fine tuned treatment but there is also a foundation that rules which is the room dimensions. The current dropped ceiling is around 2,43. I can either lower it to 2,20 or rise it to 2,75. I've done a few room modal calculations inputing my dimensions and oddly enough it seems that a lower ceiling considering my WxL would be more beneficial.

I would probably go with the Opals as the mains for that room, and maybe use the Eggs for mix checking. Especially if you decide to soffit mount (highly recommendable!), then the Opals would be the only choice as mains: I doubt it would be easy to soffit-mount Eggs!

Do you think it is possible to soffit mount the opals? I mean, they are active and really high power rated, I imagine they can get really hot so maybe it would require some kind of active cooling?

What density? How thick?

Rock wool 80 kg/m³. the recommendation was to stuff all empty space with rock wool panels as much as possible.

Please post the actual MDAT file

I am sending a link on the next post.

All I can say from that curve is that the room has major modal problems (to be expected in a small room), there are SBIR issues probably, some type of comb-filtering, and excessive treatment in the high-end: maybe a carpet on the floor? Either that, or you did the test with two speakers at once, and you happened to have the mic in a location where that causes the cancellation in high frequencies, causing the appearance of a roll off in the highs, but it isn't really there for a person sitting listening at the same location.

The test was done with both monitors positioned as such: Should I repeat with one monitor only? if so where should I place the mic? I thought the test was supposed to be stereo, my bad :lol:, I will remeasure with one speaker only and include in the file.

What do you think about a design like this? It is all absorbers but maintaining the idea of splaying and angles. I like the idea that it is modular, the panels are not attached to the walls so in case I move I can just take these with me.

Here is the latest measurement file, this time with single speaker at a time. Comments on each measurement. Hope this has been done right. Calibration MIC is a SonarWorks with calibration file for 0degree position.

If you don't want to download the files. Here are the current empty room measurements. Brick walls, ceramic tiles floor, drywall dropped ceiling. Have never seen a spectrogram and waterfall like that lol , looks like a mess .

Here is a conceptual modular idea based on the previous post.

More pics

I can see it is a very complex and trial and error process to achieve a fine tuned treatment but there is also a foundation that rules which is the room dimensions.

Room ratio (= room dimensions / room modes / modal behavior / modal spread) is just one aspect of studio design. There are many aspects that I take into account when I'm designing a room, and ratio is only one of them. It's not even the most important one (unless the ratio is really bad).

The current dropped ceiling is around 2,43

If you have a drop ceiling in your room, then start by taking it out! Drop ceilings are no use for studios, and they don't change the modal behavior in any case. Room modes are low-frequency standing waves. They form between the massive, hard, rigid, solid boundaries of the room. Light-weight thin soft "acoustic" drop ceilings do practically nothing to affect room modes. So take out the drop ceiling, and wither leave the original hard boundary ceiling as it is, or build a new "inner-leaf" ceiling below that, properly decoupled from the original ceiling. If you leave the original ceiling as it is (probably the best option), then you could improve modal response by hanging a hard-backed ceiling cloud at an angle of the front of the room (between the speakers and the desk), then putting absorptive treatment over most of the rest of the ceiling surface.

I've done a few room modal calculations inputing my dimensions and oddly enough it seems that a lower ceiling considering my WxL would be more beneficial.

True, but I would not do that in your room. If you lower the ceiling, you reduce the room volume considerably. That's not good. Your room is already small, with low volume, so you need to maximize that. The modal behavior would be better with a lower ceiling, but in your case total volume is more important. Lowering your ceiling by 15cm reduces room volume from 33m³ to 31m³. Not good. The improvement in modal response is small, but the loss of room volume is large.... In any case, those are the dimensions of the outer shell of the studio: the actual final dimensions for the inner-leaf will be less than that. Those are the dimensions you need to use.

Do you think it is possible to soffit mount the opals?

Yes, certainly.

I mean, they are active and really high power rated, I imagine they can get really hot so maybe it would require some kind of active cooling?

According to the manual, typical power consumption is around 250 Watts, with maximum peak power at 750 Watts. With a properly designed soffit, that should be possible to handle just with convective cooling, but to be safe you could put in some small fans somewhere, to ensure adequate airflow.

Rock wool 80 kg/m³.

That's too dense for good low frequency adsorption. Optimum density with most types of mineral wool is about 50 kg/m³, and you could go a little lower than that, if you wanted better low frequency absorption.

the recommendation was to stuff all empty space with rock wool panels as much as possible.

That recommendation is correct, but the density is not.

The test was done with both monitors positioned as such: Should I repeat with one monitor only? if so where should I place the mic? I thought the test was supposed to be stereo, my bad :lol:, I will remeasure with one speaker only and include in the file.

OK, I took a look at your test data, and there are several things wrong with the way you are testing. First, your levels are too low. You did the tests at a level of about 68 dB, but you need about 85 dB. Low level will probably not trigger all the modes. So check that your system is calibrated correctly (using a proper hand-held sound level meter), then repeat the tests at 85 dB. Second, you only ran the tests from 30 Hz up! Your Opals are capable of much better than that, and you are not testing the low end of the room response. Run your tests from 15 Hz to 22 kHz. Third, your speakers seem to be set up VERY differently: Check that all of the controls on both speakers are set to the "0" position, and that there is no EQ on your console, sound card, pre-amps or anywhere else in the signal path. Fourth, your speaker/mic positioning is not correct. Set up your mic 145cm from the front wall, on the center-line of the room (equal distance form both side walls) and with the tip of the mic 120cm above the floor, angled upwards at about 60°. Then set up the speakers so the acoustic axis (not the center of the woofer cone!) is 120cm above the floor, and 84cm from the side wall (so the speakers will be 132cm apart). The acoustic axis of the speaker is the point where the sound seems to come from. Most manufactures provide that information. You might need to contact them to ask, but I would estimate that it is about 30cm up the front baffle, roughly, and on the vertical center-line of the speaker. Angle the speakers so that they are both pointing at the same spot about 30cm behind the mic. Make sure that the rear corner of the speaker is about 10cm away from the front wall. That is approximately the correct geometry for your room (empty). Run your REW tests like that. Also, use the "start delay" option on the measurement window of REW. Set that to give you enough time to get out of the room and close the door, plus a couple of seconds for the sound and air to calm down a bit. It's not good for you to be inside the room when you do the measurements, since your body can change the readings, and you would not be in the exact same position every time in any case. So it is better for you to be out of the room. Also set "Sweeps" to 2, With the system set up like that, calibrate everything to do the tests at a level of 85 dB for each individual speaker, without clipping or distortion, then do not touch the settings after that! Do one test with just the left speaker, one test with just the right speaker, and one test with both speakers. Mark each test in REW to identify it. Oh, and one more thing: don't use the Eggs for this test. Use the Opals.

What do you think about a design like this?

I think that would cause rather severe artifacts in the mid range, and not provide enough bass trapping or first-reflection treatment... :) It would be better to go with a conventional design concept that is known to work, rather than trying to invent an entirely new concept.

It is all absorbers

No it isn't! You have major diffusive and reflective elements all along the sides! Those vertical slats.... They are all the same size, depth and spacing, so they will be causing strong lobing patterns... As well as probably acting as tuned devices, absorbing some frequencies more than others...

but maintaining the idea of splaying and angles.

I'm not seeing that in the design you showed. You are splaying your TREATMENT, not your WALLS. In order to created an RFZ concept, the actual walls (or soffits) need to be splayed. Your angles are also wrong. You will need much larger angles than that in small room, to create a proper RFZ.

Calibration MIC is a SonarWorks with calibration file for 0degree position.

Nice mic, but your photo shows the mic pointed directly towards one of the speakers. That's fine if you want to measure the SPEAKER response in an anechoic chamber, but not for measuring ROOM response. Point the mic straight forwards, and angle it upwards 60°. Make sure the tip of the mic is 120cm above the floor.

Have never seen a spectrogram and waterfall like that lol , looks like a mess

Right! That's because you did not do the measurements correctly, and also because you are not looking at the data correctly... :) Please set up the room as I described above, and do those three tests, then post the new MDAT file for us to look at and analyze properly.

Here is a conceptual modular idea based on the previous post.

... and it still has numeric-sequence diffusers in it! :shock: :cop: :blah: Forget about those in such a small room. Read the book by Cox and D'Antonio on diffuser theory and design, to understand why this is a bad idea... You also need to adjust your camera parameters in the render engine to something more realistic! The settings you have right now are hugely distorting the perspective. Use real-world camera settings. - Stuart -

Once more, I can't thank you enough. I am learning a lot and hopefully I will be able to achieve a good plan with your help! Here it goes.

If you have a drop ceiling in your room, then start by taking it out!

Here in brazil the apartment buildings ceilings are not very thick concrete, they look like a honeycomb. I can take out the dry wall ceiling but I have issues with the concrete honeycomb. Maybe I can rebuild the dry wall ceiling higher and with double insulation? I am guessing the honeycomb pattern will be of no benefit.

With a properly designed soffit

Would you have an example to show? I want to look into that, also the Opal is not perfectly rectangular, I would have to make a custom front fascia for it to perfectly contour its shape.

Optimum density with most types of mineral wool is about 50 kg/m³

I can choose from 48, 64 and 80.

OK, I took a look at your test data, and there are several things wrong with the way you are testing.

OK, i've repeated the measurements following your guidelines. I think I have discovered the issue on 300 to 500hz range infinite delay. My apartment is just a few meters away from the sea, I mean, right in front, with windows closed I can hear the waves crashing. So I did an RTA in total silence and there is clearly the sea sound on that frequency range as you can see on this graph: On this graph the black curve is the RTA and green is the taken measurement. I guess I won't be able to properly measure the room before isolating the window with double glazing which I plan to do soon. Here is the link to the new measurement file

I think that would cause rather severe artifacts in the mid range, and not provide enough bass trapping or first-reflection treatment... :) It would be better to go with a conventional design concept that is known to work, rather than trying to invent an entirely new concept.

my bad! I thought I was being clever, I followed Johns small studio design, sort of, as explained on this thread.. back to the drawing board it is...

Oh, and one more thing: don't use the Eggs for this test. Use the Opals.

My opals are not here to test at this time, I will remeasure with them by the end of the week.

Pictures of the setup. Tip of mic 120cm above ground and angled 60 degrees. Speakers 10cm from back wall and distance as advised on previous post.

ceilings are not very thick concrete, they look like a honeycomb.

Excellent! You are one lucky guy!

I am guessing the honeycomb pattern will be of no benefit.

It is absolutely VERY beneficial! There's a lot of diffraction, diffusion, and other good stuff going on with that. I would expect that your modal issues in the vertical plane will be minimal. Probably your best bet here is to fill the cavities in the "honeycomb" with insulation, and hide it with a fabric cover of some type, and a ceiling cloud (or several smaller clouds). So when you measure the room height, please give the measurement form the floor to the BOTTOM edge of the concrete webs, and also all the way up to the top of the wells between the webs.

Would you have an example to show? I want to look into that

There are several very good examples in the threads of various forum members, showing how they built their soffits. I don't have any bookmarked right now, but if you search for "soffit mount" and "flush mount" you will probably find hundreds of threads, and many of those will show how to do it. But the basic concept is simple: You need a very strong, rigid frame, with a very thick, massive, rigid front panel, and a hole cut in that for the speaker to come through. The speaker is mounted in one of two ways inside the soffit. It is either held in place very rigidity with a tight-fitting massive box around it, or it is held in place resiliently, with some type of vibration mount.

also the Opal is not perfectly rectangular, I would have to make a custom front fascia for it to perfectly contour its shape.

Yep. Many speakers these days are not simple rectangles, and the soffit panel has to be cut to shape to fit around them. It's not that hard to do, and the benefit is well worth the effort! If you don't have the skills and tools to do it yourself, then hire a master cabinetmaker to cut the hole for you. A small price to pay...

I can choose from 48, 64 and 80.

Go with 48. That would be the best.

So I did an RTA in total silence and there is clearly the sea sound on that frequency range as you can see on this graph:

Interesting! So you do have an isolation problem: you will need to isolate your room, for sure. You will not be able to mix when you have ambient sounds like that in the lows and low-mids...

I guess I won't be able to properly measure the room before isolating the window with double glazing which I plan to do soon.

:ahh: Double glazing???? :shock: :cop: Bad idea! commercial double glazed units have two panes of thin glass with a thin air gap between them. That's great for thermal insulation, reasonably good for voice and traffic isolation, but lousy for music isolation. It does not isolate well at low frequencies: To do that, you need two panes of thick glass, separated buy a large airspace...

Here is the link to the new measurement file

Much better! The curves for the two speakers are a much better match for each other. Clearly, you have good symmetry now, and your speakers are set up close to identically. You forgot to include the third test (with both speakers on), but that's OK. This is fine for now. If you listen to music like that, with your head where the mic is, you should notice the large improvement in bass response, stereo imaging, and clarity. Try that, and let me know if you think it sounds a lot better than it used to, just from setting up the speakers correctly. OK, what I am seeing in your data is that the room is VERY live, and needs a lot of treatment. Right now, the decay time is around 600 ms, but for that size room it should be more like 200 ms, so you are going to need a lot of treatment. You also have modal problems at 32Hz, 47 Hz, 86 Hz, 108 Hz, 140 Hz, 152 Hz, 158 Hz, and 176 Hz. and others, plus some general mid-range brightness, and a lot of background noise.

Pictures of the setup.

Excellent! So now you have a good "baseline" data set for your room, and the issues are clear. 1) First, you will need to isolate that room to get rid of the background noise. The obvious source of a lot of that noise is clearly the window, so your first plan should be how to deal with that. I would suggest that you seal those existing windows in place with good quality caulk, filling all the tiny gaps and cracks, then put a second window across the inside of that one, with as big of an air gap as you can possibly do. Make that window from thick laminate glass (8+8mm at least, with an acoustic interlayer), and seal that in place as well. When you do that, clean both windows to perfection, because you will never be able to get inside them ever again, to clean them! Also put Silica Gel in the gap (calculate the right amount!), to adsorb any moisture that is trapped in the middle, so it cannot fog or condense on the glass, and line the edge of the hap with fiberglass insulation wrapped in black cloth. That should give you much improved isolation through the window, but you should also check for other paths where noise could be coming in. Then you are going to need large bass traps in the rear corners of your room. Make them Superchunk style, for maximum effect. You will also need thick insulation on your first reflection points (at least 10cm thick), and also thick insulation between the speakers and the front wall (10cm... that's why I asked you to leave a 10cm gap there, behind the speakers). That is simple basic treatment that you can do right now, to make your room partly usable while you carry on figuring out the design. You will be able to use all of that later, in the final room, but this will at least allow you to use the room to a certain extent in the mean time. It will take you weeks to do the actual complete design, but at least the room will be basically OK until then. - Stuart -

Stuart, quick question before proceeding. I was wrapping my head around the soffit mounting and how to achieve in my room. If I was to obey your guidelines for the monitor placement, the soffits would take a huge amout of space as seen in the pics below. What do you think?

Response from Event regarding soffit mounting the opals:

Hi Diogo, Thanks for getting in contact. Technically speaking as the speakers are front ported, it is possible to soffit mount them. That said however, they are designed as free standing monitors and as that is the case, soffit mounting is untested. We would not recommend sofft mounting the speakers. I'm afraid most of our users simply use these free standing as intended so I am unable to offer up any prior experience with the speakers having been soffit mounted. Sorry we can't be more assistance. Regards, Matt Springall Service & Support - Australia RODE Microphones / EVENT Electronics

Adam said the same thing about the A7X... On the other hand... : I could show you the final acoustic response graphs for the first case above, if you want. The outcome is nothing short of spectacular. It is also not true that only front-ported speakers can be soffit mounted: in reality, rear-ported speakers can also be soffit mounted.... It's just a bit more complicated to do that. I'm working with one of my customers and also with the chief engineer of the speaker manufacturer to do soffit mount a pair of rear-ported speakers. It will work just fine... The only speakers that most definitely should not be soffit mounted, are the strange ones that have additional drivers poking out the sides, bottom, or top (some Barefoot models, for example). Apart from that, it is possible to soffit-mount pretty much any speaker, provided that the soffit is designed correctly. I bet I could even soffit-mount your Eggs... it would be very complicated to do that, but I it could be done. The key is correct design, then correct tuning.... As long as you know what you are doing, and think it through carefully, there's no problem. There's no reason why your Opals can't be soffit mounted, except that a service guy at their Australian operation doesn't want the liability of saying it would work. ( Even though he DID say it would work... :) ) - Stuart -

Yeah! I could imagine. I just posted it here for the history. Did you have a chance to look at the post before that regarding the Soffit mounting distances between speakers? If I was to keep them 132cm apart as advised on the measurement setup, I would lose almost 70% of the front room and would cover my window which I wouldn't be able to do that extremely. How bad would be to increase the spacing of speakers to clear more room for the window ?

Stuart. I am digging the idea of removing the dry wall ceiling and stuffing the combs with insulation. as for to cover it with fabric I hd an idea to use a thin PVC membrane called Barrisol. They say It is acoustically transparent almost but it has a nice property that allows for light diffusion so I can plase LED lighting on top of it and have all of the ceiling light up uniformely. Here is some date on it: I can choose either from the perforated or the non perforated version. Is this suitable for this project?

Did you have a chance to look at the post before that regarding the Soffit mounting distances between speakers?

If I was to obey your guidelines for the monitor placement, the soffits would take a huge amout of space as seen in the pics below. What do you think?

That looks about right, yes. I would suggest that you make the soffit panels even wider. The concept of soffit mounting is to create an "infinite baffle", that extends the front baffle of the speaker cabinet itself, over a much larger area. That eliminates all of the ugly artifacts that arise from having a speaker inside the room, such as comb filtering, SBIR, phase cancellations, edge diffraction, and many others. With a soffit mount, technically the speaker is not really in the room at all! If it isn't in the room, then it cannot create those artifacts... :)

If I was to keep them 132cm apart as advised on the measurement setup, I would lose almost 70% of the front room and would cover my window ...

We can probably adjust things to uncover the window a bit. I have developed a method for doing that while also not shrinking the soffit. It is possible.

How bad would be to increase the spacing of speakers to clear more room for the window ?

It is possible, yes, but you will need to recalculate the geometry, and change the angle of the speakers, as well as perhaps the location of the mix position. This is what studio design is all about: compromising some things to make other things better. That's what I do all the time when I'm designing a studio! It's a continuous process of adjusting one thing to make some aspect better, then adjusting a bunch of other things to compensate for that, then adjusting even more things to compensate for those changes... Sometimes I feel like a dog chasing his own tail around in circles, and never quite catching it! :)

as for to cover it with fabric I hd an idea to use a thin PVC membrane called Barrisol. They say It is acoustically transparent almost but it has a nice property that allows for light diffusion so I can plase LED lighting on top of it and have all of the ceiling light up uniformely. Here is some date on it:

Looks interesting, but hold of on that idea for a bit: you do not yet know what frequencies you will need to treat on your ceiling, so what it is showing there in the data sheets might be good, or it might be bad! You'll have to wait until the design is more advanced and you have some projections of what the ceiling is going to be doing, then you can decide on that. It's too early to make that decision. By the way, there is something badly wrong with the way you are setting the camera parameters in SketchUp: it is causing terrible distortion of some of the views. Make sure that the "field of view" is set to no more than about 45 degrees, and no less than about 30 degrees. Anything outside that range will exaggerate and distort perspective too much. Try something around 42 degrees. - Stuart -

It is possible, yes, but you will need to recalculate the geometry, and change the angle of the speakers, as well as perhaps the location of the mix position.

Soundman, Does the speaker need to seat in the horizontal center of the baffle on the soffit? Or can it be offset to either side?

Soundman2020 wrote:

There's no reason why your Opals can't be soffit mounted,-

The Opal has a somewhat rounded design, not only on the 2d plane but also 3d plane.the shape is curved both on the X, Y, and Z axis it should be difficult to match the front bezel considering all the planes. Should I make the front baffle flush with the woofer and tweeter part? or flush with the end of the front ports? you can see what I mean on the pictures attached.

Here is a new study of the soffits considering the 45 degree angle and keeping the 38% mixing position with a larger baffle. Still need to decide how to position the baffle in relation with the Opals considering their Odd shape and different z planes on the front.

Here is a new REW file with panels I made just seating on the walls. Nothing too fancy. 50mm rockwool. 12 panels The panels are not finished I think I need to increase the thickness to help with reverberation times on lower octaves. What do you guys think? Download REW

Here is the before and after of Spectrogram