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And yet another thread of home studio acoustic treatment.
Old 10th March 2021 | Show parent
  #31
Quote:
Originally Posted by D13b9 ➡️
What do you think about the measurements?
I only see one measurement in your .mdat...

Your pics are very good and I appreciate that you left a bit of room at the top for a ceiling cloud (clever planning).

52 Hz is still decaying slowly (is that the 0-0-1 mode?) and the decay times go up in the midrange which means you'll need more treatment but not always of the deep kind.

I find it hard to decypher what's what mode in your .mdat because of the room but I would maybe do one more of the deep traps and play with lighter side wall and ceiling treatment or treat the entire ceiling with a panel from the front to the rear.
Old 10th March 2021 | Show parent
  #32
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Quote:
Originally Posted by johannburkard ➡️
I only see one measurement in your .mdat...
You are right. My bad!!

I have updated my previous post and I have posted the different measurements in several files.
Old 11th March 2021 | Show parent
  #33
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Quote:
Originally Posted by johannburkard ➡️
Your pics are very good and I appreciate that you left a bit of room at the top for a ceiling cloud (clever planning).
Thanks johannburkard for taking the time to look at the charts and for all your advice.

Quote:
Originally Posted by johannburkard ➡️
52 Hz is still decaying slowly (is that the 0-0-1 mode?) and the decay times go up in the midrange which means you'll need more treatment but not always of the deep kind.
No, according to Amroc that is my 1-0-0 mode relative to the length of my room (336 cm).



For the 0-0-1 mode of the ceiling (258 cm) it marks 66.47 Hrz



and for the 0-1-0 of the width (254 cm) 67.52 Hrz.



https://amcoustics.com/tools/amroc?l...6%20-%20Studio

From what you comment on the decay times going up in the mid frequency zone, it is something that seems to happen when placing the Soffits in the rear corners of the back wall



but instead this effect is reduced by placing the Soffits in the corners of the front wall.



In all the tests I have done it seems clear that the 1-0-0 mode does not flinch and the decay time is not greatly reduced at 52Hrz.

What should I do with these Soffits? I leave these four placed in the front corners and do another four deeper Soffits to try to attack at 52Hrz?

Quote:
Originally Posted by johannburkard ➡️
I find it hard to decypher what's what mode in your .mdat because of the room but I would maybe do one more of the deep traps and play with lighter side wall and ceiling treatment or treat the entire ceiling with a panel from the front to the rear.
Excuse me, but I can't quite understand the last part here. Could you please specify a little more? You mean doing another batch of 4 Soffits? or just another one?

When it comes to making the ceiling, I do not know very well how to focus it regarding thickness and materials on the possible needs of the room so I would appreciate any suggestions.

If it is necessary to cover a large area of the ceiling I will do it. I cannot make a large panel since I am living for rent and I will be leaving the house in no less than 2 years so I would like to be able to reuse everything I build here for the next studio so for the ceiling I will opt for individual panels but as I have already said before, if all the surface needs to be treated that will not be a problem.

Thanks again in advance!
Old 11th March 2021 | Show parent
  #34
Quote:
Originally Posted by D13b9 ➡️
Excuse me, but I can't quite understand the last part here. Could you please specify a little more? You mean doing another batch of 4 Soffits? or just another one?
I think there may be room for another one towards the exit, behind the one on the left? Alternatively, build two more and stack them left and right to you (if you can lose the space).

Quote:
Originally Posted by D13b9 ➡️
When it comes to making the ceiling, I do not know very well how to focus it regarding thickness and materials on the possible needs of the room so I would appreciate any suggestions.
Well, you've kept a bit of room above the soffit traps. How much is that? Looks like 20 cm?
Old 11th March 2021 | Show parent
  #35
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Quote:
Originally Posted by Hot Sauce ➡️
Nice! Good call on the polyester batting, btw.
Hello Hot Sauce, the truth was that there was a moment I was worried about getting a fine finish on my panels but after reading the recommendation of Polyester as an intermediate layer between fiber and fabric in several threads I didn´t think twice and I ordered a roll.

Quote:
Originally Posted by Hot Sauce ➡️
Are you only using fluffy for this build or are you going to use some slightly denser stuff anywhere?
I am glad that you asked me this question and above all that you have brought up the subject of using different densities in panel construction because I am very interested in giving it a try.

My room is very small and really the only area where I can occupy more space to place a lot of thickness with treatment are the corners. These Soffits are 40cm thick and at first I was thinking of making another batch of 4 but first I wanted to share the measurements before continuing to make more panels because I want to make the decisions based on the results.

If the thickness is not enough to dissipate my first mode close to 50 Hrz as has been shown in the waterfalls guess I can always do the following Soffits something deeper with more fluffy or try 40cm of fluffy + a denser layer or rockwool. It is also one of the reasons why I have not lined the panels with fabric because if it were necessary to add a layer of another material that way it would be easier for me.

The problem that I see in all this combining densities is when choosing the materials since I am not quite clear about how many KPa.s/m2 the layer with the highest density should be and also its thickness and how much material with low GFR/AFR use.

To give an example when treating a ceiling with a supposed 0-0-1 mode at 66 Hrz as is my case, what can be the proportions for a thickness between 20 and 25cm? 4 cm of a 22 kPa.s/m2 material and then 16 or 20cm of another with 5 kPa.s/m2? Or would it be better to use instead of 16 cm of 5 kPa.s choose something more dense,for example 10kPa.s/m2 since it seems more optimal material for that thickness?

Where this topic can also be very interesting to me could be in the area of ​​the first reflections. I have less space there so anything I can save would be good news.

Finally, I would like to make two gobos for the back that on the one hand serve as a bass trap and at the same time be able to open them to use in recording acoustic guitars, vocals and some minor percussion so I am also open to suggestions.

But I find that it is still too early to think about this since first I have to do the ceiling and first reflection panels and then I´ll be able to consider how to make the gobos and off course always making decisions regarding what the room demands after each measurement.
Old 11th March 2021 | Show parent
  #36
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Quote:
Originally Posted by johannburkard ➡️
I think there may be room for another one towards the exit, behind the one on the left? Alternatively, build two more and stack them left and right to you (if you can lose the space).
I guess I can always make 2 in the corner of the exit as you suggest and leave the other corner free. If later I need more absorption or balance the room I am always on time to do that part but the truth is the corners are not the most compromised area of ​​the room so I will surely make soffits for both sides.

I have some fiberglass strips to spare and I have been thinking of taking them home (I am doing the assembly in the warehouse at work due to lack of space) and place them behind the Soffits to test if the absorption around 50Hrz improves.

Quote:
Originally Posted by johannburkard ➡️
Well, you've kept a bit of room above the soffit traps. How much is that? Looks like 20 cm?
The space I have left is 18cm, is that enough?. Keep in mind that it´s not important because if I really need more depth in the ceiling I can always make the next Soffits a few cm lower and place these first 4 down as bases in all the corners and thus adapt the new ones so that they are just below the ceiling panels.

It just occurred to me that perhaps it would be a good idea to first make 2 panels that are placed on the part of the ceiling that is above my listening area and thus be able to know the behavior in the measurements. That way if I am short in thickness I can add another layer of treatment and if the results are good, do the rest of the ceiling and also the second batch of Soffits.

Do you think this may be a good idea? If so, how thick would you make these two panels of the ceiling?
Old 11th March 2021 | Show parent
  #37
Quote:
Originally Posted by D13b9 ➡️
The space I have left is 18cm, is that enough?
It's better than nothing.

Quote:
Originally Posted by D13b9 ➡️
It just occurred to me that perhaps it would be a good idea to first make 2 panels that are placed on the part of the ceiling that is above my listening area and thus be able to know the behavior in the measurements.
That is a good idea. I'd use up the whole 18 cm.
Old 11th March 2021 | Show parent
  #38
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Quote:
Originally Posted by D13b9 ➡️
The problem that I see in all this combining densities is when choosing the materials since I am not quite clear about how many KPa.s/m2 the layer with the highest density should be and also its thickness and how much material with low GFR/AFR use.

To give an example when treating a ceiling with a supposed 0-0-1 mode at 66 Hrz as is my case, what can be the proportions for a thickness between 20 and 25cm? 4 cm of a 22 kPa.s/m2 material and then 16 or 20cm of another with 5 kPa.s/m2? Or would it be better to use instead of 16 cm of 5 kPa.s choose something more dense,for example 10kPa.s/m2 since it seems more optimal material for that thickness?

Where this topic can also be very interesting to me could be in the area of ​​the first reflections. I have less space there so anything I can save would be good news.

Finally, I would like to make two gobos for the back that on the one hand serve as a bass trap and at the same time be able to open them to use in recording acoustic guitars, vocals and some minor percussion so I am also open to suggestions.

But I find that it is still too early to think about this since first I have to do the ceiling and first reflection panels and then I´ll be able to consider how to make the gobos and off course always making decisions regarding what the room demands after each measurement.
I will not pretend to be enough of an expert to fully answer your question, as it's a complicated subject and a lot depends on the situation, but I will share my own experiences.

First of all and the thing I am most confident about, I would definitely make gobos and I have personally seen an advantage to having a thin layer of higher GFR material on one side, simply because 1) it allows a relatively thinner panel to have a greater effect in the low frequencies, and 2) this gives you options as to which side you have facing the room and they will behave a bit differently in either case. Keeping the layer thin means that the issue of reflection caused by high gfr materials is minimized. Compared to wall panels, they will usually be spaced significantly farther, which increases the LF absorption, at the cost of some reflection at 1/2 wavelength multiples of the air gap distance. However this effect can be mitigated significantly by the thickness (i.e., the thickness reaches "past" the half wavelength distance significantly), and I would not consider this detrimental compared to the overall improvement.

I have two gobos that are not particularly thick, only about 110mm total. They are faced with polyester batting about 10mm, with is I believe around 2000 rayls/m, and not a significant contributor, in the middle is 75mm ~10000 rayls/m material and backed with ~30000 rayls/m material. Obviously as gobos it is quite easy to move them around and flip them over. They work quite well when the polyester is in front. If I place them in specific areas there is a noticeable difference in the low frequencies, and this effect is also noticeably greater if I turn them so the high GFR is in front.

But do note that this is largely affected by where they are placed. If they're in the middle of the room I notice less of an effect on the low frequencies but the overall broadband absorption is increased. I think, though again I am no expert, that this may be a difference between velocity vs. pressure. Since the dense material exhibits a slight membrane like effect, this is greater at areas of high pressure, i,e, corners, but velocity based absorption is greatest where the particle velocity is greatest, i.e., the middle of the room. I hope I am correct about this - in any event this description lines up with what I have observed.

I have one corner in particular (my room has a couple of odd features that make it not a perfect rectangle), where 40Hz is crazy crazy loud. If I line these two gobos up covering that corner (which already has a chunk in it, mind you) with the dense material facing the room, the 40Hz buildup is significantly less.

The biggest advantage to making the panels floorstanding is just being able to move them around to get the best result for the situation.

If your intention is to make floor standing panels that can unfold, and be useful as both bass traps, but also absorbers for recording, then you could make the unfolded panels backed with a thin layer of higher GFR material, and when folded, this would mean that the panel would have high GRF material on both the front and back which should increase the LF absorption somewhat. However my understanding is this also increases the reflection of some frequencies. If they are far away from you and surrounded by other broadband absorption hopefully this effect will be less impactful than the positive effects of low frequency absorption.

However regarding materials choice I think just as in any other situation it's going to depend on the thickness you're doing for. My panels were not that thick so I went for a 10000 rayls/m base material, and I maybe could've even gone for 15000, but 10000 is what I had. If you go much thicker, a lighter material might be best. And I think the thicker the panel is, the more it is going to absorb in the low frequencies even before putting a dense layer on one side. So for example if you had a 300mm thick panel, you might cut my numbers in half and go for 5000/15000 rayls/m.

For the ceiling I think there may be less need for a higher GFR material simply because the panels tend to already be spaced farther from the boundary, and the ceiling is an area where the space is not missed very much if the panels are made quite thick. So for that I would just go for whatever material is appropriate for the depth of the panel, go as thick as possible, and hang them as low as possible. As you may know, the general rule of thumb for GFR/thickness is something like this:

0-100mm, semirigid type batts ~20000 rayls/m, preferably with a 25-50mm air gap (though with any of these products the actual number can vary and it's important to see what's available locally).

100-250mm, lower density mineral fiber (in the US, Rockwool Safe N Sound is THE material in this range - it is about 10000 rayls/m).

250mm+, fluffy attic insulation like you're already using, usually about 5000 rayls/m.

I have also had pretty good results facing my clouds with polyester batting, since this helps to just keep everything contained and prevent fiber from falling onto you while you are working!

Again I am not an expert studio designer so please take this with a grain of salt, this is all just from my own understanding and experience. The subject gets very complicated and it's always better to trust the people who fully understand it, imo! But from a practical standpoint I think it is better to go with approaches that are easier to execute. There are all kinds of ideas I've seen with introducing small air gaps within the panel traps between materials of higher/lower GFR layered several times... but at the end of the day, is the benefit of this worth the extra work and complexity, and is it really so much better than just putting a half meter of fluffy insulation along the wall?
Old 11th March 2021 | Show parent
  #39
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By the way, wanted to just change directions for a moment and mention that if after you hang your cloud you are still having issues with 50Hz and 66Hz, maybe you could consider some membrane absorbers.

I made a few BBC A10 style membrane absorbers and they work very well. They are definitely a bit harder to get right than porous absorbers, which are just frame em and hang em. However they can target the frequency more effectively.

See where your cloud gets you - I think it may make a huge difference. But if you are still having problems at certain low frequencies, then maybe consider some A10 style absorbers - they have a center frequency right around 55-80Hz, if built correctly, but you can make the cavity slightly deeper and that should lower the frequency a bit, or increase the mass of the membrane. Placement is critical, though. I have one odd closet corner that has an insane amount of 70Hz, and I hung one of my A10s in that corner and it goes nuts when I play a 70Hz tone, even if it's quiet. It seems the A10 is a little different than some membrane absorbers because it is lower Q and wider range. Adding a few of these and putting them in the right spots really helped reduce a huge peak in my room.

It is true they are harder to make properly, but with a bit of care it can totally be done. I sealed my box from the inside with silicone and that seemed to do the trick. I'm sure there are many ways it could be done.
Old 12th March 2021
  #40
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Soffits +10 & +20

As I mentioned yesterday in my last post, I took home several pieces of fluffy for tests in which I increased the thickness of the Soffits (+ 10cm and + 20cm) both in the back of the room and in the front.

I am attaching a few screenshots of L and R in the back wall and also front wall of my studio (20 - 20000 Hrz).
Attached Thumbnails
And yet another thread of home studio acoustic treatment.-02-l-soffit-back.jpg   And yet another thread of home studio acoustic treatment.-03-l-soffit-10-back.jpg   And yet another thread of home studio acoustic treatment.-04-l-soffit-20-back.jpg   And yet another thread of home studio acoustic treatment.-06-r-soffit-back.jpg   And yet another thread of home studio acoustic treatment.-07-r-soffit-10-back.jpg  

And yet another thread of home studio acoustic treatment.-08-r-soffit-20-back.jpg   And yet another thread of home studio acoustic treatment.-09-l-soffit-front.jpg   And yet another thread of home studio acoustic treatment.-10-l-soffit-10-front.jpg   And yet another thread of home studio acoustic treatment.-11-l-soffit-20-front.jpg   And yet another thread of home studio acoustic treatment.-12-r-soffit-front.jpg  

And yet another thread of home studio acoustic treatment.-13-r-soffit-10-front.jpg   And yet another thread of home studio acoustic treatment.-14-r-soffit-20-front.jpg  
Old 12th March 2021
  #41
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Here L + R in the back and then in the front (20 - 500 Hrz).
Attached Thumbnails
And yet another thread of home studio acoustic treatment.-15-l-r-soffits.jpg   And yet another thread of home studio acoustic treatment.-16-l-r-soffits-10.jpg   And yet another thread of home studio acoustic treatment.-17-l-r-soffits-20.jpg   And yet another thread of home studio acoustic treatment.-18-l-r-soffis-front.jpg   And yet another thread of home studio acoustic treatment.-19-l-r-soffis-10-front.jpg  

And yet another thread of home studio acoustic treatment.-20-l-r-soffis-20-front.jpg  
Old 12th March 2021
  #42
Thickness sideways or lengthwise?
Old 12th March 2021 | Show parent
  #43
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Quote:
Originally Posted by johannburkard ➡️
Thickness sideways or lengthwise?
I have been very busy and I have found a hole this afternoon to post the results but I have not been able to specify, sorry.

The added thickness has been relative to the depth of the panel. Here is a photo where you can see more clearly:

Old 13th March 2021
  #44
Doesn't look like that makes much difference but I assume you will working on the room?
Old 13th March 2021 | Show parent
  #45
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Quote:
Originally Posted by johannburkard ➡️
Doesn't look like that makes much difference but I assume you will working on the room?
No, it doesn't seem to contribute in improving the absortion at low frequencies.
I guess what this means is that it is better to treat more surfaces than not having a couple of thick absorbers.

This was a test out of curiosity but now it's time to get down to work with the ceiling.

Quote:
Originally Posted by johannburkard ➡️
That is a good idea. I'd use up the whole 18 cm.
I'll do that. I will try 18 cm and from there we will see.

Yesterday I was at Brico Mart and bought more insulation. For a thickness of 18/20 cm I understand that it is recommended that the material have a GFR / AFR somewhat higher than the one I have used in my Soffits.

For the ceiling I have chosen to work with Knauf insulation, specifically Knauf TP 116 with a density of 16Kg / m3 and an AFR of 10kPa.s / m2. Each sheet is 135cm x 60cm x 10cm although I have to say that that 10cm is not exact since at most it is 9cm and I am being generous.

EDIT: After having worked a lot with this KNAUF product I can confirm that its thickness corresponds to the 10cm indicated by the manufacturer. It simply takes more than one day to regain its thickness.
Old 13th March 2021 | Show parent
  #46
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If you want to experiment, since your ceiling material is not super high AFR, you could try putting a layer of it on the front of your soffits and just take a measurement and see if the result is different.
Old 13th March 2021 | Show parent
  #47
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Quote:
Originally Posted by Hot Sauce ➡️
I will not pretend to be enough of an expert to fully answer your question, as it's a complicated subject and a lot depends on the situation, but I will share my own experiences.
Sorry I couldn't answer you earlier. These last two days I´ve been quite busy.

First of all thank you for sharing your experiences with me and for having detailed everything as you have done. For me it is of great help.

Quote:
Originally Posted by Hot Sauce ➡️
I have two gobos that are not particularly thick, only about 110mm total. They are faced with polyester batting about 10mm, with is I believe around 2000 rayls/m, and not a significant contributor, in the middle is 75mm ~10000 rayls/m material and backed with ~30000 rayls/m material. Obviously as gobos it is quite easy to move them around and flip them over. They work quite well when the polyester is in front. If I place them in specific areas there is a noticeable difference in the low frequencies, and this effect is also noticeably greater if I turn them so the high GFR is in front.

But do note that this is largely affected by where they are placed. If they're in the middle of the room I notice less of an effect on the low frequencies but the overall broadband absorption is increased. I think, though again I am no expert, that this may be a difference between velocity vs. pressure. Since the dense material exhibits a slight membrane like effect, this is greater at areas of high pressure, i,e, corners, but velocity based absorption is greatest where the particle velocity is greatest, i.e., the middle of the room. I hope I am correct about this - in any event this description lines up with what I have observed.

I have one corner in particular (my room has a couple of odd features that make it not a perfect rectangle), where 40Hz is crazy crazy loud. If I line these two gobos up covering that corner (which already has a chunk in it, mind you) with the dense material facing the room, the 40Hz buildup is significantly less.

The biggest advantage to making the panels floorstanding is just being able to move them around to get the best result for the situation.
It seems very interesting and it is something that I have read in other threads such as treating the ceiling with very high density panels between 4 and 8 cm and filling the rest with fluffy or adding a very thin layer (around 2 cm) in front of some Soffits such as the ones that I have done.

And the truth is that having the option of adding that higher GFR layer with a Gobo seems a very good idea and above all comfortable. As I have not yet planned to cover anything with fabric or Dacron until I have everything a little clearer, I do not rule out trying to buy some wool of about 22 kPa.s/m2 and 4cm thick and do the test. Everything will depend on the results obtained but I appreciate that you have exposed it since it helps me to have other perspectives.

So far I have not come across any insulation as thin as the one you mention, around 2cm, but I'm sure there must be too.

Quote:
Originally Posted by Hot Sauce ➡️
If your intention is to make floor standing panels that can unfold, and be useful as both Bass Traps, but also absorbers for recording, then you could make the unfolded panels backed with a thin layer of higher GFR material, and when folded, this would mean that the panel would have high GRF material on both the front and back which should increase the LF absorption somewhat. However my understanding is this also increases the reflection of some frequencies. If they are far away from you and surrounded by other broadband absorption hopefully this effect will be less impactful than the positive effects of low frequency absorption.

However regarding materials choice I think just as in any other situation it's going to depend on the thickness you're doing for. My panels were not that thick so I went for a 10000 rayls/m base material, and I maybe could've even gone for 15000, but 10000 is what I had. If you go much thicker, a lighter material might be best. And I think the thicker the panel is, the more it is going to absorb in the low frequencies even before putting a dense layer on one side. So for example if you had a 300mm thick panel, you might cut my numbers in half and go for 5000/15000 rayls/m.
I'm still not sure how thick should the gobo on the back wall be, but the truth is that at first I was thinking around 30cm and having one of the faces with the highest density and the other made with fluffy. That way, on the one hand, you could have the higher GFR layer in front and if this effect was not the desired because some undesired frecuencies have beeing reflected I could place the denser face facing the wall it would have, as you mentioned previously, a more broadband effect.

Although I still see this part far away. Now I will start working with a denser meterial than fluffy and I really want to see how it works. It scares me a little if I fall short in thickness of the ceiling making the panel 18 or 20 cm since I have read on several occasions that 20cm is the minimum for broadband but I have also just seen it very clear with my Soffits that probably treating the entire surface is really important vs having a large absorbent with "the right thickness". And also at the same time since I won´t finish covering it with fabric always be in time to add another layer of the same material or remove everything and put something denser in front and then add the 10kPa.s material or more fluffy.

I guess this game is about making decisions and being open to making changes and experimenting.

Quote:
Originally Posted by Hot Sauce ➡️
0-100mm, semirigid type batts ~20000 rayls/m, preferably with a 25-50mm air gap (though with any of these products the actual number can vary and it's important to see what's available locally).

100-250mm, lower density mineral fiber (in the US, Rockwool Safe N Sound is THE material in this range - it is about 10000 rayls/m).

250mm+, fluffy attic insulation like you're already using, usually about 5000 rayls/m.

I have also had pretty good results facing my clouds with polyester batting, since this helps to just keep everything contained and prevent fiber from falling onto you while you are working!
It seems that this part I have it well understood but again thank you for confirming the information.

The polyester that I have bought is 150mm thick and 150 gr/m2 but I do not know the Air Flow Resistivity values. If I remember it this Monday I will send a message to the manufacturer to know the data and I will share it here in case someone is interested in the future.

Quote:
Originally Posted by Hot Sauce ➡️
Again I am not an expert studio designer so please take this with a grain of salt, this is all just from my own understanding and experience. The subject gets very complicated and it's always better to trust the people who fully understand it, imo! But from a practical standpoint I think it is better to go with approaches that are easier to execute. There are all kinds of ideas I've seen with introducing small air gaps within the panel traps between materials of higher/lower GFR layered several times... but at the end of the day, is the benefit of this worth the extra work and complexity, and is it really so much better than just putting a half meter of fluffy insulation along the wall?
I guess life would be very boring if we did not have that tendency to complicate ourselves so much, don't you think?
Old 13th March 2021 | Show parent
  #48
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The truth is that this is a subject in which I have not immersed myself too much. Since I consider myself a DIYer denied, this option has always seemed very complex to me, but I don't rule it out either since I imagine that is difficult to deal with big modal problems only working with absorber panels.
Old 13th March 2021 | Show parent
  #49
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It seems like a great idea and also this material is much more grateful to transport and unlike fluffy it does stand up without problems so after having made the first ceiling panels I will try to do what you say in your message.

I will also put 2 sheets on each side of my right and left listening position to see how this material works as first reflection panels and keep experimenting before making the wooden frames.
Old 13th March 2021 | Show parent
  #50
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No worries I'm glad to share what I've done.

The one I used is Rockwool Rockboard which is available in the US in thicknesses as thin as 1 inch (25mm). It was actually given to me by my father who had used it to line the inside of a small shack he made for an electric generator to keep the noise down. The cost to return ship it to the manufacturer was about equal to the refund he would have received so he just gave it to me instead.

I wouldn't have normally thought to use a material with so high of an AFR value but I would have to say it has worked out well and it can definitely be useful in certain situations. 30000 rayls/m is a bit high to be sure, but after all, free is free. I think your idea to get something around 22000 is appropriate. And anyway it is not totally certain the exact AFR of the rockboard, there is a range it will tend to be, so it may have been more or less than 30000, there's no way to be sure.

One advantage however of the high AFR of the rockboard I have is that a very thin layer of it can have a noticeable effect. So while the cost is often higher, there is no need to buy a large amount of it - certainly not like fluffy attic insulation which must be bought in large quantities. But there is no real need to go for such a high value as I did, which was simply due to getting it for free. The advantage of the lower AFR like 22000 rayls/m is it is probably more useful on its own too.

I wonder about using it for first reflection as the addition may increase the reflection of the lower mids, but i think you're in an ideal situation to just try a few things out, take measurements, and compare.
Old 13th March 2021 | Show parent
  #51
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Quote:
Originally Posted by Hot Sauce ➡️
But there is no real need to go for such a high value as I did, which was simply due to getting it for free. The advantage of the lower AFR like 22000 rayls/m is it is probably more useful on its own too.

I wonder about using it for first reflection as the addition may increase the reflection of the lower mids, but i think you're in an ideal situation to just try a few things out, take measurements, and compare.
Regarding the reflection of low medium frequencies, I suppose that it is an issue to take into account and more in the area of early reflections. Perhaps it is more interesting to use this method as you mentioned in the previous message as a front layer in areas with higher sound pressure such as corners. Maybe it could be an option for ceiling panels that meets the walls.

As I mentioned previously, the good thing is how grateful it is to work with more rigid materials. I will take a few empty boxes from work so that I can place the panels at an optimal height so that they work as early reflections panels. I hope I can be doing these measurements throughout the week and know how the 10 kPa.s/m2 material works in my room.
Old 13th March 2021 | Show parent
  #52
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I've had great results with 10kPa.s/m2 so hopefully it works well for you
Old 17th March 2021
  #53
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D13b9's Avatar
 
screenshots

Hey guys yesterday I did some tests around my room and I have images to share of the comparison between the measurements. Before exporting the screenshots I wanted to ask you about the graphics in the Spectrogram, what do you think is a recommended value in dBs for the Scale Bottom to get rid of the noise floor? Is 20 dB a good value?

Thanks in advance.
Attached Thumbnails
And yet another thread of home studio acoustic treatment.-screenshot-scale.png  
Old 17th March 2021 | Show parent
  #54
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🎧 5 years
Quote:
Originally Posted by D13b9 ➡️
... Before exporting the screenshots I wanted to ask you about the graphics in the Spectrogram...,
Why don't you upload your mdats so we can show you?

Best
Old 17th March 2021 | Show parent
  #55
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Quote:
Originally Posted by akebrake ➡️
Why don't you upload your mdats so we can show you?

Best
It is just that I did several tests with different positions of the absorbents and also at different thicknesses so the REW file is around 70 megabytes.

I will try to upload them separately.
Old 17th March 2021
  #56
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I have brought home the entire package of Knauf wool to do several tests before making the panels and it will allow me to know how the 10 kPa.s/m2 responds.

All measurements are made with floor to ceiling 40cm x 40cm Soffits (5kPa.s/m2) placed at my front wall corners.

In all measurements the wool sheets have been placed 50cm from the ground and in this way the center of the absorbent remains centered with respect to the height of my listening position. I have placed boxes of fruit upright and to help prevent the wool from falling to the ground I used some pieces of cardboard on the top of the boxes.

Attached 3 files (Note: in each of the REW measurements I have written a note describing the material used and the dimensions of the absorber to help identify each of them)

- Before. The room's frequency response only with the Soffits.



- 10Kpas Side.

Here are 4 different combinations in the early reflections zone.

- 1 and 2: L / R with a Panel of 135x60x20cm at both my left and right (10 kPa.s/m2)



- 3 and 4: L / R with a Panel of 135x60x30cm at both my left and right (10 kPa.s/m2)



- 5 and 6: L / R with a Panel of 135x60x30cm (20cm of 10 kPa.s/m2 facing de room + 10cm of 5 kPa.s/m2 facing the wall).




- 7 and 8: L / R with a Panel of 135x120x20cm at both my left and right (10 kPa.s/m2)





- 10Kpas Front-Back.

- 1 and 2: L / R with a Panel of 135x60x10cm behind both my speakers (10 kPa.s/m2)



- 3 and 4: L / R with a Panel of 135x60x20cm behind both my speakers (10 kPa.s/m2)



- 5 and 6: L / R with a Panel of 135x120x20cm at the center of the back wall (10 kPa.s/m2)



- 7 and 8: L / R with a Panel of 135x120x30cm at the center of the back wall (10 kPa.s/m2)

Attached Files
File Type: mdat Before .mdat (4.93 MB, 5 views) File Type: zip 10Kpas Side.mdat.zip (14.59 MB, 3 views) File Type: zip 10Kpas Front-Back.mdat.zip (14.62 MB, 3 views)
Old 18th March 2021
  #57
I don't have too much time to look into this but "L - 135x120x20cm" looked the best. Good impulse response and the best spectrogram of all tests in my opinion.
Old 19th March 2021
  #58
Gear Maniac
 
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Side Walls treatment

Here are a few snapshots of the measurement of the left speaker in the different configurations I tested on the side walls in the early reflections zone:
Attached Thumbnails
And yet another thread of home studio acoustic treatment.-00-l-before.jpg   And yet another thread of home studio acoustic treatment.-01-l-20cm.jpg   And yet another thread of home studio acoustic treatment.-02-l-30cm.jpg   And yet another thread of home studio acoustic treatment.-03-l-20-10cm.jpg   And yet another thread of home studio acoustic treatment.-04-l-135x120x20.jpg  

And yet another thread of home studio acoustic treatment.-05-r-before.jpg   And yet another thread of home studio acoustic treatment.-05-rt60-1oct.jpg   And yet another thread of home studio acoustic treatment.-05-rt60-2oct-2.jpg   And yet another thread of home studio acoustic treatment.-05-rt60-2oct.jpg   And yet another thread of home studio acoustic treatment.-06-l-before.jpg  

And yet another thread of home studio acoustic treatment.-07-l-20cm.jpg   And yet another thread of home studio acoustic treatment.-08-l-30cm.jpg   And yet another thread of home studio acoustic treatment.-09-l-20-10cm.jpg   And yet another thread of home studio acoustic treatment.-10-l-135x120x20.jpg   And yet another thread of home studio acoustic treatment.-11-l-before.jpg  

And yet another thread of home studio acoustic treatment.-12-l-20cm.jpg   And yet another thread of home studio acoustic treatment.-13-l-30cm.jpg   And yet another thread of home studio acoustic treatment.-14-l-20-10cm.jpg   And yet another thread of home studio acoustic treatment.-15-l-135x120x20.jpg  
Old 19th March 2021
  #59
Gear Maniac
 
D13b9's Avatar
 
Right speaker snapshots of the measurements on the side walls in the early reflections zone:
Attached Thumbnails
And yet another thread of home studio acoustic treatment.-00-r-rt-one-o.jpg   And yet another thread of home studio acoustic treatment.-01-r-rt-third-o.jpg   And yet another thread of home studio acoustic treatment.-02-r-rt-third-o.jpg   And yet another thread of home studio acoustic treatment.-16-r-before.jpg   And yet another thread of home studio acoustic treatment.-17-r-20cm.jpg  

And yet another thread of home studio acoustic treatment.-18-r-30cm.jpg   And yet another thread of home studio acoustic treatment.-19-r-20-10cm.jpg   And yet another thread of home studio acoustic treatment.-20-r-135x120x20.jpg   And yet another thread of home studio acoustic treatment.-21-r-before.jpg   And yet another thread of home studio acoustic treatment.-22-r-20cm.jpg  

And yet another thread of home studio acoustic treatment.-23-r-30cm.jpg   And yet another thread of home studio acoustic treatment.-24-r-20-10cm.jpg   And yet another thread of home studio acoustic treatment.-25-r-135x120x20.jpg  
Old 19th March 2021
  #60
Thanks for being thorough, @ D13b9 . It's always interesting to see someone work on a small room.
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