Home Studio Treatment - Measurments and Questions

[fiskmaas]

Hi AVNirvana!

So I'm looking to do some upgrades to my home studio in terms of acoustic treatment. At the moment I only have some 1 and 2 inch cheap foam at first on first reflections on the walls and ceiling, and a bookshelf in the back right corner. I realize they don't do all that much and I'm thinking I will make some 4" DIY absorption panels for the first reflections, and some alternating diffusers.

I've just received an UMIK-1 and have done some measurements and I've attached the results. Am I to understand that the decay times look descent, at least for mids and highs? There are also some inconsistencies between the right and left, I'm guessing it might have to do with the front window that has some depth to it (23cm deep), but would love to get you guys input on this as I'm fairly new to this.

The buildup at ~130hz I think is partly due to the speakers: but I'm guessing also the desk and side first reflections aren't helping.

Edit: btw the ceiling is sloped and the dotted lines are just there for the drawing and my calculations. There's not actually anything there.

Advice and input welcomed!!

 

[ddude003]

Hello @fiskmaas If you look at the Klippel charts that are available (https://www.audiosciencereview.com/...ali-spektor-1-review-bookshelf-speaker.25063/) for your Dali SPEKTOR 1, your speakers seem to be right in that ballpark... I averaged your 3 Left and your 3 Right responses and and looked at what the Klippel expected in room response might be and your averaged Left and Right responses seem about right... I would recommend the, more or less, standard base traps in the corners and some wide band absorbers on the walls... Cover the window with some heavy curtains or a wide band absorber... If you do EQ/DSP with your kit then you could create yourself a house curve and wrap some EQ/DSP filters around that... It looks like your room is in control below the Schroeder frequency and your speakers are in control above, which is normal...

Maybe you could elaborate on your use of this system and how it currently sounds...

 

[fiskmaas]

Hello fiskmaas If you look at the Klippel charts that are available () for your Dali SPEKTOR 1, your speakers seem to be right in that ballpark... I averaged your 3 Left and your 3 Right responses and and looked at what the Klippel expected in room response might be and your averaged Left and Right responses seem about right... I would recommend the, more or less, standard base traps in the corners and some wide band absorbers on the walls... Cover the window with some heavy curtains or a wide band absorber... If you do EQ/DSP with your kit then you could create yourself a house curve and wrap some EQ/DSP filters around that... It looks like your room is in control below the Schroeder frequency and your speakers are in control above, which is normal...

Hi @ddude003, thanks for the reply and looking into my measurements. The measurements are done on my monitors, the Presonus Eris E5s, not on the Dalis. I attached a SPL graph in the main post of those, unfortunately that's all I could find on them.

I will look more into house curve and treatment. Would I need bass traps in all corners, or would a couple in the front suffice?

 

[ddude003]

Here are the Klippel charts for the Presonus Eris E5s... https://www.audiosciencereview.com/...s/presonus-e5-xt-active-speaker-review.13436/... Pretty close to the Dalis... Maybe a little less mids & treble...

For best results place base traps where 3 surfaces, 2 walls and floor and/or two walls and the ceiling, come together... Then 2 surfaces, a wall and ceiling etc... See http://arqen.com/bass-traps-101/placement-guide/ for some examples... How much and how many depends on how thick, big, materials and where your placing them... Thicker is better, think 6 to 8 inches... And how flat and dry you are trying to get your room... Again, what is your use? Listening, mixing, vocals???

 

[fiskmaas]

Here are the Klippel charts for the Presonus Eris E5s... Pretty close to the Dalis... Maybe a little less mids & treble...

For best results place base traps where 3 surfaces, 2 walls and floor and/or two walls and the ceiling, come together... Then 2 surfaces, a wall and ceiling etc... See for some examples... How much and how many depends on how thick, big, materials and where your placing them... Thicker is better, think 6 to 8 inches... And how flat and dry you are trying to get your room... Again, what is your use? Listening, mixing, vocals???

Those are for the XT's, they're similar but not entirely the same, although maybe good enough for this purpose.

I see. Yes they will have to be pretty big, which is my main concern. I'll have to do physical measurements to see where I could fit them.

Oh sorry, didn't see that you had asked. My main use is mainly mixing/mastering and producing.

 

[ddude003]

I missed the difference with the E5s and XTs... And for this comparison purpose we don't need to split hairs... The real point here is that you are doing a near field mixing and mastering kit and room... If you haven't already read up on the subject, I would suggest you have a look around at some reference materials...
http://arqen.com/acoustics-101/room-setup-acoustic-treatment/#reverb-time... Look at his "cheat codes" for coverage
Master Handbook of Acoustics, Seventh Edition 7th Edition by F. Alton Everest... Some chapters on absorber designs
Recording Studio Design, Third Edition (Audio Engineering Society Presents) 3rd Edition by Philip Newell

 

[fiskmaas]

I missed the difference with the E5s and XTs... And for this comparison purpose we don't need to split hairs... The real point here is that you are doing a near field mixing and mastering kit and room... If you haven't already read up on the subject, I would suggest you have a look around at some reference materials...
Look at his "cheat codes" for coverage
Master Handbook of Acoustics, Seventh Edition 7th Edition by F. Alton Everest... Some chapters on absorber designs
Recording Studio Design, Third Edition (Audio Engineering Society Presents) 3rd Edition by Philip Newell

Thanks a bunch, I will look into it and come back with updated measurements!

 

[fiskmaas]

Allright I've done some measuring, and I think I've come up with something somewhat reasonable. What's your opinion on placement?

The absorption panels are too thick to be placed vertically and not hit the desk, because they need to be above the desk to get the first reflection. Made a quick 3D drawing to scale.

I'll probably fill the back of the side walls with another vertical panel, or maybe a diffuser, but this will be my first step.

I'm also considering putting basstraps in more corners, but it will be hard to make them symmetrical, would that be an issue if I for instance put a panel on only one of the back corners, and not the other? Say where the bookshelf is positioned.

First reflections:

12  cm deep - 95mm of which is rockwool
75  cm wide
175 cm long

Bass trap:

20  cm deep - 2x 95mm rockwool
50  cm wide - leaves 25-30 cm behind to corner - could maybe go up to 60 and get even more space behind it.
190 cm long

 

[ddude003]

It looks like you are off to a good start @fiskmaas... The depths of your absorbers looks good and standing off the walls/corners by several inches helps, even tunes depending on the stand off... You will want to try and get your front wall and first reflection points as symmetrical as is reasonable given your restraints... Just keep in mind that you may need more coverage to meet your reverb (0.2 to 0.4 sec) and bass control goals... Meaning still more absorption at and near the rear wall(s) if that's possible... First steps look good... With next steps in mind...

 

[fiskmaas]

Ok so I've gotten the first two panels made (finally), for first reflections. Made 100 x 50 x 12 cm panels and filled them with 100mm rockwool. It made a big difference, especially in reverb time and things sound a lot clearer when mixing. Success!

I've also added a thick curtain over my window, but there seems to be some difference between the channels still, so I'm wondering, is this within an acceptable difference range? I do hear differences when mixing at times, but I don't know if it's normal or not. Most noticable in the lows 80-200 hz

 

[ddude003]

Hello @fiskmaas, Nice work so far... I would go ahead and make another pair of absorbers, bass absorbers... They need to be much thicker, at least as thick as your above 20cm and even more, 25 to 30cm thick... Once you have those in hand you may be able to adjust the placement of all the absorbers to adjust for some of the asymmetry your seeing and hearing... An inch or two adjustment of the speakers and absorbers can make a lot of difference... As you are the mix, master and producer, it is up to you how you want things to sound and how things will translate to the various systems your listeners will have...

 

[fiskmaas]

Hello @fiskmaas, Nice work so far... I would go ahead and make another pair of absorbers, bass absorbers... They need to be much thicker, at least as thick as your above 20cm and even more, 25 to 30cm thick... Once you have those in hand you may be able to adjust the placement of all the absorbers to adjust for some of the asymmetry your seeing and hearing... An inch or two adjustment of the speakers and absorbers can make a lot of difference... As you are the mix, master and producer, it is up to you how you want things to sound and how things will translate to the various systems your listeners will have...

Hi @ddude003, thanks!

Yes bass traps are next in line. These first reflection absorbers were only 12cm thick, of which 10cm is rockwool.

I have wood that's around 20-25 cm, would that do well you think, with some room behind in the corners or should I shoot for 30cm right off the bat?

 

[ddude003]

Hi @fiskmaas... Your latest .mdat attachment showed a low frequency peak at ~140Hz... So I would shoot for something that would cut that a bit... I don't think "wood that's around 20-25 cm" would work out to well... You want 25 to 30cm of absorbent... You could add a thin (1/8 to 1/4) ply or pegboard in front as a "strike plate", thin plastic or even thick butcher paper to the front of the absorber to reflect the high frequencies and still absorb the lows... Maybe play around with this acoustic modeling application at:

Multi-layer Absorber Calculator

and see what combinations might help...
You might also look at the designs of these bass traps from GIK https://www.gikacoustics.com/product-category/bass-traps/ the 5.25 and 7.3 inch get you in the ball park...

 

[fiskmaas]

Thanks, I'll have a look.

Yeah, the 20-25 cm of wood would just be a square frame to hold the absorbant.

 

[ddude003]

Ahhh... On edge as a frame sounds like a plan...

 

[fiskmaas]

Ahhh... On edge as a frame sounds like a plan...

Mounted bass traps in front. 20cm thick rockwool with ~30cm space behind to the corner. The left one had to be a bit smaller due to the window. No real SPL change but RT60 looks a bit better at least.

 

[ddude003]

@fiskmaas that looks a little better overall... I bet that ~140Hz peak is from table or ceiling reflections... For kicks try and place a few layers of towels on the table and see if the table and/or a mixing console or workstation monitor is causing that... Maybe you can raise the monitors... You may have to resort to some room correction EQ to push that down towards flat...

 

[fiskmaas]

I tried putting down a bunch of towels and another small panel I made on the desk at the reflection points and not much changed really.

My monitors are behind the front of the speakers so they shouldnt (?) interfere...

The ceiling is sloped upwards so it shouldn't interfere either right?

 

[ddude003]

You might refer to those Klippels above... I know they are not exactly your monitors and they do show how monitors similar to yours radiate sound lol in all directions... And as Maxwell suggests, all things transmit and receive... You could always get a string, mirror and/or a flashlight and _see_ where things can reflect from and to... And low frequency is everywhere, its everywhere... The "shouldn't" seem absolute... The real question is how much do they help in the grand scheme of things... My guess is not so much...

 

[fiskmaas]

You might refer to those Klippels above... I know they are not exactly your monitors and they do show how monitors similar to yours radiate sound lol in all directions... And as Maxwell suggests, all things transmit and receive... You could always get a string, mirror and/or a flashlight and _see_ where things can reflect from and to... And low frequency is everywhere, its everywhere... The "shouldn't" seem absolute... The real question is how much do they help in the grand scheme of things... My guess is not so much...

I see. I did try removing my monitors and again no difference. I suppose it could be the window but I'll have to go hunting.

Edit: I tried putting a panel in the window and it didn't help the 135hz bump but what it did do was help a dip from the right speaker at 90hz so there's that.

I also played around in the room sim and it points to that the ceiling might be the issue so I'll try getting a panel up there today to see if it helps

 

[fiskmaas]

built another absorber (120 x 60 x 20 cm) for the back ceiling corner. I tried a couple spots, back corner and first reflection, both in the ceiling. No big spl change unfortunately.

Edit: also tried it in the window, of which it filled up about 90% of, still not much change.
Edit2: Added R, L and R+L after I have hung the absorber in the back. Not sure what happened with the left channel, I did it twice and turned out like that both times.

 

[ddude003]

Unfortunately your fighting room modes... Do you have your sub turned on? And have you tried moving the sub around the room? I would try stacking two of your 20cm absorbers to see if you can get any movement below 200Hz... What SPL are you targeting for your frequency sweeps? 80 or 85db?

 

[fiskmaas]

Unfortunately your fighting room modes... Do you have your sub turned on? And have you tried moving the sub around the room? I would try stacking two of your 20cm absorbers to see if you can get any movement below 200Hz... What SPL are you targeting for your frequency sweeps? 80 or 85db?

I have no sub, only the Eris E5s. Usually 80db but I don't always check.

I might be able to stack one of the 20cm with two 12cm. Just put them anywhere? Might be able to just put them in the left back corner, or in the middle...

 

[ddude003]

Oh, you list a JBL GTO 1014 in your More config... That is fine you don't use it... I would try the front corners and/or back corners with thicker absorbers... How high are they placed? Approximately how much of the surface area of the room is covered now?

 

[fiskmaas]

Oh, you list a JBL GTO 1014 in your More config... That fine you don't use it... I would try the front corners and/or back corners with thicker absorbers... How high are they placed?

I have used it at times but I think I'll just get a Presonus Sub 8 eventually, the JBL is a hacky setup and a hassle to set up. I don't think I'm able to fit any more in the front.

Attached an image to illustrate.

Edit: Tried to stack them on the floor at the back middle and left corner, but no change in SPL...