Farmhouse home studio construction

Hi Janne, I have found a measuring graph on your thread and did an additional room mode calculation with the room width and the room lengh :) The room width has a mode in the center of 120hz and the Room lengh of 100hz. Both modes are first standing room modes and become a problem in the center of the room. In the graph is also shown a thicker outer wall of the right side and a thick wall on the front. I guess these are massive walls. Can you recognize with a sine generator on 100hz a maximum at the front of the room? There should be a second maximum at the rearwall but depending on the wallthickness behind your absorber not as loud as the front section. the same with the 120hz mode - do you recognize a maximum on the right side where the massive wall is? The second mode should also be at the opposite but as it is an inner wall not as loud as on the massive side. This could be the reason for your different measures on left and right speaker. The wall-mode is triggered more or less depending on the space of the speaker to the wall and weight/stiffness of the wall itself. I did a large research and only two layer drywall on the opposite wall can create a mode even if there are no massive walls only drywall. Another question what frequency did you tune your slot wall? Usually if this is the case, the most effective would be to put a big superchunk on the front maxima and focussing the right slot wall to 120 hz. OR lean back one meter for mixing ;) Regards Aaron

Hi Aaron and thanks again :D My house is an old wooden house so the walls are not very massive. Front wall and right wall, yes those are more massive than the back wall and the left wall. I suppose there are 150mm wood studs with insulation between the wall cavity, then 12mm Particle board. I attached also 15mm firerated gypsum for extra sound isolation layer. Back wall and the left wall is only 2x4" wood studs with gypsum layer on both sides. Outer side is a layer (maybe two layers) of 12mm gypsum and inside layer is 15mm gypsum board. I didn't build this house so I don't know the actual materials which the builder had used. Only visible ones.. :D I made the test as you were adviced. Firstly tested with 100Hz sinewave. And yes the maximum was at the front wall. 10 dB louder than the mixing position. At the back wall it was only 3 dB louder than the mixing position. Both speakers allmost the same measurements +/- 1dB. Second test. 120Hz sinewave. Right speaker: At the mixing position 3dB louder than at the left wall and 3dB quieter than at the right wall. (Mp 65dB, Lw 62dB, Rw 68dB) Left speaker: At the mixing position 1dB louder than at the left wall and 5 dB louder than at the right wall. (Mp 64dB, Lw 65dB, Rw 60dB) I also made the following tests as you earlier suggested. Here are some graphs and test fotos: First test: Rock wool sag and additional corner bass traps stacked in front of the angled back wall part. Left speaker measurement at the mixing position: Right speaker measurement at the mixing position: Second test: Same setup but in the corner where the entry door is. Left speaker measurement: some reason the problem frequency turned around between the speakers?? Now the 110Hz dip is more deeper at the left speaker measurement... Right speaker measurement: actually quite good :) +/- 5dB Third test: Same setup as second test but the door is now open and the absorbition stack is in the hall. Left speaker measurement: Right speaker measurement: As the problem frequency spikes are quite sharp. Could I build panel trap or traps tuned on 100-120 Hz and place them on problem spots? Could it be the cure? Many thanks again Aaron :D -Janne

Hi Jane, Very interesting! So much is going on there so here are my thoughts. Pic1: rockwool placed in the center of the rear wall. The 110 mode is looking 7db better for the left speaker. No big changes for the right speaker at 110hz. Theres also a second mode at around 190hz that looks around 10db better for both speakers. I assume that this mode has been before but hard to see cause your old measuries show a small dip at 190hzA too and maybe the intense in the new measuries is different caused by a different mic position just some cm... Wow. The right speaker has not the 190 drop anymore too. Looks good. This frequency is a candidat that can be absorbt with > 45cm rockwool very fine instead the 110 mode. I can not guarantee that a thinner absorber can be as effective for 190hz but you might try 15cm of 60kg rockwool as a kind of big additional hanger bags in the center of the rearwall, close to the slot wall. Pic2: Rockwool at the left corner. Both corners must be mode maximas for the 110hz cause it looks much better if you place the rockwool bag there. 8db better on the right speaker and what is going on with the left speaker? I guess it does not have a big effect for the left speaker placing the bag there. it seems to have something to do with the wall mounted speakers that they push the sound pressure more to the diagonal corners. Testing this could be tuning a sinus wave 110hz out of the left speaker and listen at the diagonal right corner if there is a louder max than at the left corner. Pic3: Rockwool at left corner. Hey, here you hit the bulls eye again i think. This is looking good on both speakers. Funny to see that the 190 hz drop is there again on the left speaker but not even as much on the right. So i think the 190 hz must be a mode coming from the center-right part of the rear-wall. The 110db are only 6-7db on both speakers. Nice. But as i wrote i think you have an additional room mode at 2,85m width that makes your peaks on the measures wider, nice to see on lspkr_3 pic.

Could i build panel trap or traps tuned to 100-120 Hz and place them on problem spots?

Yes, this is what i actually going to do in my room. Our problem is the space and that we have to fight with modes that absorbers usually need alot of space :) so in theory panel absorbers and helmolz kind resonators should be the way to go to save space and getting the room response nearly flat. As slot walls are some kind of helholz resonators i think it is not bad going with it but they also reflect a lot and need to be deeper than Johns standard slot wall. Thats the reason i asked about the frequency you tuned yours. If you did not tune the rearwall slot wall to your mode you may should consider using this space for a new slot wall around 20cm deph from wall and 15cm slats 3mm slots 22mm thick slats. Maybe a mix for 110hz and 190hz. I still think the 120hz is a mode of the room width. You can see on your actual measuries there is a low dip at around -9db that does not even change on the graphs. So usually you should add a 120hz slat to your sidewall slotabsorbers. Hard to check but try to put a big bag on the sidewall and we will see if there is a change on 120hz then. Panel absorbers are not easy to build and they are big reflecting surfaces. I think it would be more effective to build a Heavy-weight-foil absorber. This is the same like the vibrating plate but with a 5-6kg /qm foil instead. You might wait till i am done with my 100hz tuned slot wall that i can tell you if it makes sense to overwork yours :wink: It would also be interesting now making a measuring with two or three bags placed at the corner between the door and center part of the rearwall. If the theory is right the 190drop must be away on both speakers and the 110drop must be similar to your last measuring :) Best regards Aaron

"Panel absorbers are not easy to build and they are big reflecting surfaces. I think it would be more effective to build a Heavy-weight-foil absorber. This is the same like the vibrating plate but with a 5-6kg /qm foil instead." If by panel you mean membrane, what is the difference between a panel and a foil membrane? Either one can be difficult to figure...but you still have to figure either one and you still have to build it.

xSpace wrote:

If by panel you mean membrane, what is the difference between a panel and a foil membrane? Either one can be difficult to figure...but you still have to figure either one and you still have to build it.

Hi xSpace, good question. I also did not see people build foil resonators here... in german forums they are compared and discussed more often ...instead of other more importand things like very nice people you might better find here :) membrane and foil works the same principLe in theory but for a 0,3-0,4 thick heavy-foil you need less deph for the resonator. The front is also not as flat and stiff like a plywood 4mm panel and wood panels tend to post vibrate some ms. Mdf more than pressboard or plywood. http://62.75.219.232/safranedriver-p18h ... 2db97e34a0 This foil is not a pond foil. It is most times heavier and commonly used for cars to avoid vibrating of the thin metals. I often read people build panel resonators they are not effective. There are also VPR resonators with a thin steel sheet onto a basotec that could be considered for this low frequency range but i most often readed people have had good sucess with these foil resonators. As you say we must try it at least. Maybe a panel resonator is just good as a foil resonator if it is build well and good in place but with a wood panel there will still be the big flat reflecting zone that may could bother in context to the small room size. Again, all theory. I did not build this foil absorber myself yet but reading good things about it. Best regards Aaron

aaronsommer wrote:

Thats the reason i asked about the frequency you tuned yours. If you did not tune the rearwall slot wall to your mode you may should consider using this space for a new slot wall around 20cm deph from wall and 15cm slats 3mm slots 22mm thick slats. Maybe a mix for 110hz and 190hz. I still think the 120hz is a mode of the room width. You can see on your actual measuries there is a low dip at around -9db that does not even change on the graphs. So usually you should add a 120hz slat to your sidewall slotabsorbers. Hard to check but try to put a big bag on the sidewall and we will see if there is a change on 120hz then.

Sorry I forgot to answer that tuning question.. Actually rearwall angled absorber is not hemholtz type resonator at all. I didn't seal it's cavity. It's just an absorber and I added slats in front of it to keep a little high frequency energy in the room. Whereas side wall absorbers are hemholtz slot resonators. I didn't tune them any specific frequencies. I should have calculate room modes before I cutted those slats :oops: Slats sizes are 120mm, 70mm and 30mm, slots are 2,5mm, 5mm and 10mm. Cavity behind it changes from 70mm to 250mm. I'm thinking that my side wall resonators don't go low enough to handle that problematic frequency 120 Hz... I'm gonna test it like you said. Putting a rockwool bag against the right wall and taking new measurement. If there's a remarkable improvement then I could tune half of the right wall to handle 120 Hz? Let's say hight of the speaker soffit starts to the ceiling. How's that sounds to you?

aaronsommer wrote:

Panel absorbers are not easy to build and they are big reflecting surfaces. I think it would be more effective to build a Heavy-weight-foil absorber. This is the same like the vibrating plate but with a 5-6kg /qm foil instead. You might wait till i am done with my 100hz tuned slot wall that i can tell you if it makes sense to overwork yours :wink: It would also be interesting now making a measuring with two or three bags placed at the corner between the door and center part of the rearwall. If the theory is right the 190drop must be away on both speakers and the 110drop must be similar to your last measuring :)

I was wondering the same thing as Brien but at the meanwhile I wrote this post you already answered us :D But yeah! I've got no rush. I'm waiting that you finish your slot wall. Then we both are wiser about this subject :idea: I'll also do this other measurment as you said at the end of your post. Let's see what happens. This is definitely getting interesting :-D Thanks! -Janne

limsa-terry wrote:

Sorry I forgot to answer that tuning question.. Actually rearwall angled absorber is not hemholtz type resonator at all. I didn't seal it's cavity. It's just an absorber and I added slats in front of it to keep a little high frequency energy in the room.

Hmm yes and i guess the measures would look much better if there were tuned. Maybe you have to take use of your great carpener skills again and put in just tuned slot walls.

Whereas side wall absorbers are hemholtz slot resonators. I didn't tune them any specific frequencies. I should have calculate room modes before I cutted those slats :oops: Slats sizes are 120mm, 70mm and 30mm, slots are 2,5mm, 5mm and 10mm. Cavity behind it changes from 70mm to 250mm. I'm thinking that my side wall resonators don't go low enough to handle that problematic frequency 120 Hz...

Do you think or did you a calculation? Your slat panels are looking really thin but if they are 2cm thick you have 111hz on the deepest side and 200hz on the small angle. This is not as bad... Or how thick ware your slat panels? :)

If there's a remarkable improvement then I could tune half of the right wall to handle 120 Hz? Let's say hight of the speaker soffit starts to the ceiling.

Maybe this could improve something but you really need to re calculate your slot wall if it really can be modified to hit this frequency and check if the mode comes from the width but i still guess it. Everything makes sense so far that 120hz comes from the room width.

I was wondering the same thing as Brien but at the meanwhile I wrote this post you already answered us :D

those foil resonators seems to be interesting for small rooms even not as nice looking as slot walls :)

I'm waiting that you finish your slot wall. Then we both are wiser about this subject :idea:

yes this is a good idea. I finished the border yet and tomorrow i will cut the slats.

I'll also do this other measurment as you said at the end of your post. Let's see what happens. This is definitely getting interesting :-D

I'm curious too and am looking forward to see the measures. You might do one reference measure next time without rockwool that we can compare more easily :wink: Best regards Aaron

Have you tried swapping L and R speakers?

Bill Pillmore wrote:

Have you tried swapping L and R speakers?

Hi Bill, what do you think should happen then? :wink: Best regards Aaron

aaronsommer wrote:

Again, all theory. I did not build this foil absorber myself yet but reading good things about it. Best regards Aaron

I guess I am saying this. In order for a membrane to work it has to be tuned from the start. So if you use a steel plate or an aluminum veneered product or plywood, you still require the numbers on either of these materials to make an accurate panel, right? So, rather than deviate with unknown properties, stick with what you can verify. Unless you can verify the properties from the start, it's all guess work. And aluminum is highly, highly reflective in the high end, so while you could get lucky and produce a panel that actually resonates at the low frequency desired, the high end reflection might introduce more treatment issues than typical measures would produce.

aaronsommer wrote:

Do you think or did you a calculation? Your slat panels are looking really thin but if they are 2cm thick you have 111hz on the deepest side and 200hz on the small angle. This is not as bad... Or how thick ware your slat panels? :)

My slat panels are only 15mm thick. If I played correctly with hemholz calculator my resonators are still going to low enough 117Hz. But is that sufficient? That's a another question. Maybe there needs to be more of 120mm slats and 2,5mm slots.. I have now 120mm slat, 10mm slot, 30mm slat, 10mm slot, 120mm slat, 2,5mm slot, 70mm slat, 5mm slot, 30mm slat, 5mm slot, 70mm slat, 2,5mm slot, 120mm slat etc etc... That's the pattern.

aaronsommer wrote:

yes this is a good idea. I finished the border yet and tomorrow i will cut the slats.

I can't wait to see it finished and measured :wink:

aaronsommer wrote:

I'm curious too and am looking forward to see the measures. You might do one reference measure next time without rockwool that we can compare more easily :wink:

I'll take new measures today including the reference measure without rockwool bats :D

Bill Pillmore wrote:

Have you tried swapping L and R speakers?

Actually I did, just for curiosity if there's any differences between the speakers.. No there isn't :D Thanks, -Janne

xSpace wrote:

aaronsommer wrote:

Again, all theory. I did not build this foil absorber myself yet but reading good things about it. Best regards Aaron

I guess I am saying this. In order for a membrane to work it has to be tuned from the start. So if you use a steel plate or an aluminum veneered product or plywood, you still require the numbers on either of these materials to make an accurate panel, right? So, rather than deviate with unknown properties, stick with what you can verify. Unless you can verify the properties from the start, it's all guess work. And aluminum is highly, highly reflective in the high end, so while you could get lucky and produce a panel that actually resonates.

Brien, Yes i know that it has to be tuned from start. The foil i talked from is detailed descripted onto the page i linked and the kg/qm that is needed to calculate the resonance of the foil/plate is also standing there - 6kg/qm instead of 4mm plywood 2,4kg/qm. I did not talk from aluminum. The formula to calc this foil resonator is the same as the one of the plate resonator. And like you say an aluminum plate is high reflective cause of its material stiffness and the converse argument is that foil wound be as high reflective. Summary this Foil resonator is actually the same as the plate resonator but using a resonance calculated acoustic foil instead of a resonance calculated plywood plate. In German it is called "Folienschwinger". Literature resource about the foil resonator (sorry, german): Book - Die Audio-Enzyklopädie: ein Nachschlagewerk für Tontechniker From Andreas Friesecke Position: 1.6.4.1. http://books.google.de/books?id=r8G1oDG ... er&f=false Best regards Aaron

aaronsommer wrote:

Bill Pillmore wrote:

Have you tried swapping L and R speakers?

Hi Bill, what do you think should happen then? :wink: Best regards Aaron

I am following this thread because in about a month I will be doing this to my room too. I don't know if the software eliminates the speaker from the equation or not, but because of the difference in the graphs between speakers I wanted to eliminate that as a factor. Also the point was asked if the same slot pattern is repeated over every stud cavity on all the walls does it become more of a tuned resonator and no longer a broad band resonator? Thanks

Bill Pillmore wrote:

I am following this thread because in about a month I will be doing this to my room too. I don't know if the software eliminates the speaker from the equation or not, but because of the difference in the graphs between speakers I wanted to eliminate that as a factor. Also the point was asked if the same slot pattern is repeated over every stud cavity on all the walls does it become more of a tuned resonator and no longer a broad band resonator? Thanks

Hi Bill It doesn't eliminate speaker but interface it does. I tried after the first measure I took, to swapping speakers. Left speaker to the right soffit and vica versa. Test proved that differences between the graphs is definitely coming from my room acoustics :) In my room, on a back wall there's just two absorbers. Corner absorber and angled absorber. Slats in front of them are only to reflect a little high frequencies in the room. They are not tuned devices. I could have use plastic behind the cloth to do the same thing but slats look cooler :) Side walls are broad band resonators, because they're angled and the slat pattern is changing. Your place is starting to look really cool btw!!! :D Aaron I was able to take new measurements yesterday :D Before the reference measurement I angled my front cloud a bit more. It's now about 20cm lower at the front than before. It helped a bit at the problem spots! Left speaker reference measurement. Looks quite good to me :D Right speaker reference measurement. It's getting better. There are still dip at the 110Hz but it's not as deep as it was before :!: Second measurement. Pack of rockwool in front of the right slot wall. Left speaker measurement. It got little worse. New dip at about 130Hz! Right speaker measurement. No significant improvement. Only the dip from the 110Hz moved to 100Hz. Third measurement. Two rockwool packs. One against the rigth slot wall and the other against the angled back wall. Left speaker measurement. Looks good. Right speaker measurement. No significant improvement. My front cloud is open at the back. What could happen if I put a layer of plywood on top of it?? I must try that option! Thanks, -Janne

More measurements....... if anyone is interested :) I made the quick test how a plywood layer on top of the cloud affects on my room responce. Plywood was 15mm 120cm x 185cm, allmost the size of the cloud. Here are reference measurements without the plywood layer. Left speaker: and Right speaker: And then a plywood on top of the cloud. Left speaker: got 5dB worse on a 170Hz.. Otherwise quite the same as reference. And Right speaker: 5dB better on a 110Hz but few dB worse on 170Hz.. -Janne

Hi Janne, This measures are strange, theres a peak at 450hz right speaker after the plywood that usually should not be there... I think you have used 50kg type rockwool for the cloude, did you? How thick? From room inside: Fabric-> rockwool-> plywood? The mids and highs are looking very different that i guess the mic position was changed a little bit between both a/b measures. If the 170hz frequency is really getting that bad i would drop off this sheet again. Im still experimenting too but i have good results now, almost only one -6db peak. I rebuilt the slot walls three times totaly. It was necessary cause the first time i used too low dense rockeool and the slotresonator acted like a reverbator on 100hz. It was really :horse: but they are most effective now. There is such a big difference what rockwool you use in the slot walls and how much, it is a really damn finetune work making it 8db better or even worse if there is too less rockwool. Best Aaron

aaronsommer wrote:

This measures are strange, theres a peak at 450hz right speaker after the plywood that usually should not be there... I think you have used 50kg type rockwool for the cloude, did you? How thick? From room inside: Fabric-> rockwool-> plywood? The mids and highs are looking very different that i guess the mic position was changed a little bit between both a/b measures.

You're right. I used rockwool 40-50kg/m3 of density for the cloud. 10cm thick layer. And yes, plywood was on the top of the cloud -> from room inside: fabric -> rockwool -> plywood. I marked the measurement mic stands place on the floor with tape, but yes the mic's place can vary a few millimeters between the measures. Actually that peak at 450hz is in the left speakers reference measurement also. I allways take 3 to 5 measurements at same setup and I'm choosing the best one. Sometimes that 450hz peak is there and sometimes not..

aaronsommer wrote:

If the 170hz frequency is really getting that bad i would drop off this sheet again.

Yes maybe you're right. It got little better at 110hz on a right speaker but otherwise worse... I'm leaving it still there and finishing the backwall and door absorbers. Then taking new measurements, if it still looks bad at the 170hz. I'm taking it of.

aaronsommer wrote:

Im still experimenting too but i have good results now, almost only one -6db peak. I rebuilt the slot walls three times totaly. It was necessary cause the first time i used too low dense rockeool and the slotresonator acted like a reverbator on 100hz. It was really :horse: but they are most effective now. There is such a big difference what rockwool you use in the slot walls and how much, it is a really damn finetune work making it 8db better or even worse if there is too less rockwool.

Oh man, I can't wait your next update :D Good luck, -Janne

Hello all :D It's been a while... Finally got finished all the skirtings and other trims here and there. Very time consuming work, especially when all the walls are angled :D Pic 1. Front wall finished. Sorry about the picture quality... crappy cellphone pic. Pics 2-4. Additional backwall absorbers. Construction is simple. Frame is made of 1x4" wood. Inside filled with rockwool. In front a layer of plastic and cloth. Pic 5. Back wall finished. Pic 6. Entry door absorbers. Contruction is the same than in other two backwall absorbers. Pics 7-8. Couple of details :D Final measurement curves coming soon :D -janne

Of COURSE! Now I understand why you had those strange curves in your graphs! It's OBVIOUS! You have bagpipes in there! :) That explains everything!!! There's no telling what kind of strange, screaming, "strangled-cat" sound they are adding to your room.... Just the sight of those is scaring the hell out of the sound waves, and makes them rush around the room, bouncing off the walls, yelling and shrieking in absolute terror and extreme fear, as they desperately try to escape ... :lol: (Actually, I do have some Scottish blood in me, I love the sound of the bagpipes! I just couldn't resist the feeble attempt at humor...). Seriously, the room looks great! I love the style of decoration, and I hope those new absorbers solve your problems. I'm look forward to seeing the new graphs. - Stuart -

Hey Janne, That room looks fantastic ! you are so close to the finishing line man, Looking forward to your next post simo

Nice job, the wooden frames around the traps and your room are looking great and your picture wall is even cool :D Very huge! Aaron

Stuart, Simo and Aaron. Thanks a lot for your reeeally nice comments :mrgreen: Stuart: Bagpipes could be the reason of strange curves I manage to measure OR maybe this little furry animal: :D She's starting to get really pissed of about that sweeping sound... :lol: Ok.. Here are the final measurments: Left and right speaker 30Hz-1000Hz. Same problem spots but not as deep as before. Overall I'm now about +/- 5db at the LF range. Left and right speakers 30Hz-15000Hz. Octave smoothing is 1/12. And finally LF waterfall plots. I'm pretty happy with the results and pretty tired of measuring... I wanna mix! :D I do need to finnish my liveroom also. I'm sure everyone has forgotten this fact :D so, construction isn't over yet... What next: I need to finish a little storage room next to my control room, -finish the mixing desk, -soldering, soldering, soldering, -then continue the liveroom contruction... Thanks again! -Janne

The graphs are looking much better. Pretty darn good, actually! +/- 5 dB is excellent for a small room like that, and I doubt that you'll be able to improve much more than that. So go make music already! :) - Stuart -

Thanks Stuart Your words are music to my ears :mrgreen: -Janne

Wow! it's been awhile since my last post... I've been mostly recording and mixing my bands new album, and we are nearly finished. ...so the construction can continue... :D Drums recorded at "real" studio but everything else, guitars, basses and some vocals (we are playing instrumental space rock :D) recorded at my studio. Everything worked perfectly fine. Mixing is a lot easier nowadays, no wonder :D Mixer desk done, and my old Studiomaster mixer is fired at use also. Some cables have to be solded but mostly everthing is wired! I noticed that I'll have to buy a lot of new gear :D I now the rule here: Pics or it didn't happend :D I'll post some pics later at this evening!!! -Janne