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Room analysis shows large 64hz peak - details + pics - any advice? Studio Monitors
Old 22nd December 2010
  #1
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Room analysis shows large 64hz peak - details + pics - any advice?

Hi guys

I'm trying to treat my new room. It's a mix and production spot, but i want the mixing area accurate. I did some room analysis using a Peluso 2247LE in omni, with FuzzMeasure Pro. I used a 10sec sine wave sweep, and used the Adam S3A's. (DanDan, they are staying horizontal for a while, too much to contend with at once heh). I followed DanDan's primer and turned the mic to face the speaker.

I've taken some unflattering pictures of the room to show the current treatment, along with frequency & waterfall plots. I've done a room mode calc and am not sure how to interpret the results, but the curve generated at the bottom of bob's page looked very close to the 'good' example. I've also attached the barefoot wallbounce calc results. It seems that my setup is not too bad, according to the wallbounce.

Nothing i have done, in terms of moving panels, speakers or listening position around, has done anything to budge that 64Hz-ish peak. I've tried playing a 64hz sine wave (out of both speakers) and walking around the room, and can hear the variations.

I've been doing one speaker at a time, moving the mic roughly around mix position, and getting pretty identical results. I seem to have improved the 90-100hz null as that was rather extreme earlier (a narrow dip). To be honest i'm not entirely sure how i did that, trial and error really. When i make very small movements, i create pretty extreme nulls. What i did had no effect on the huge peak, however.

The room dimensions are: L: 7.15m x W: 5.3m x H: 2.2m

Some notes:

- Front corners are floor to ceiling 4" traps, filled with RS100 (everything's RS100 other than the small, thin, square panels which are Wickes high density insulation, the orange stuff). The four, 7' uncovered panels at the back are intended to become two hinged partitions for vocal recording, and also double up as some back wall bass trapping.
- Past these large vocal traps on the back wall the large open plan room wraps round to the kitchen area. There's no partition.
- The stairs section obviously goes up very high, giving some flutter echo.
- The 'bin-bag wall' helps to stop quite a lot of sound from leaking outside as the 4" RW5 in there really does a decent job of heat and sound insulation. This is a work in progress and will be covered in fabric.
- The walls are all stone. The one to the left of the mix position has plasterboard with some insulation on it. Front and rear of mix position is merely plaster on top of the stone/brick.
- The plasterboard ceiling is quite thin as you can hear everything that happens downstairs quite clearly. I intend to make a cloud with two, two inch, 2' x 4' panels above mix position.
- The wooden stairs section is all hollow. It's just got empty gear boxes in it and the wood is quite thin. I plan to hang some thin panels on the underside of the slanted bit, behind where the big cream 4" panel currently is.
- I planned to build a plasterboard plug with handles for the window to the left of the mix position. The gap in the wall on the right, is filled with rockwool too, and i'll put some fabric or something over it.
- The 2'x'4 panels will be raised 30-50cm off the ground, as soon as i figure out how to make some stands for them. Some of the thinner panels will be hung on the walls, obviously things aren't quite finalised yet.

I understand there's a huge amount of information here, but i'd really appreciate some advice on how to tame that 64-ish-Hz bump. I'd be more than happy to try out any suggestions you might have, or answer any questions. I hope i didn't forget anything heh

Thanks for any advice you can give!

Eddie
Attached Thumbnails
Room analysis shows large 64hz peak - details + pics - any advice?-studio1.jpg   Room analysis shows large 64hz peak - details + pics - any advice?-studio2.jpg   Room analysis shows large 64hz peak - details + pics - any advice?-studio3.jpg   Room analysis shows large 64hz peak - details + pics - any advice?-studio4.jpg   Room analysis shows large 64hz peak - details + pics - any advice?-studio5.jpg  

Room analysis shows large 64hz peak - details + pics - any advice?-studio6.jpg   Room analysis shows large 64hz peak - details + pics - any advice?-studio7.jpg   Room analysis shows large 64hz peak - details + pics - any advice?-studio8.jpg   Room analysis shows large 64hz peak - details + pics - any advice?-studio9.jpg   Room analysis shows large 64hz peak - details + pics - any advice?-studio10.jpg  

Room analysis shows large 64hz peak - details + pics - any advice?-studio11.jpg   Room analysis shows large 64hz peak - details + pics - any advice?-studio12.jpg   Room analysis shows large 64hz peak - details + pics - any advice?-freq-impulse300hz.png   Room analysis shows large 64hz peak - details + pics - any advice?-waterfall300hz.png   Room analysis shows large 64hz peak - details + pics - any advice?-wallbouncecalc.png  

Old 22nd December 2010
  #2
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Eddie, set up FM like this for better results on the waterfall.

Also appears you are not using the auto device correction due to the long delay.

Old 22nd December 2010
  #3
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That 64hz peak is almost dead on your room's main mode, according to my room mode calculator.

I suspect you need more bass traps to squash that hump in the low end, probably resonating or membrane traps, as you have a buildup in a specific area, one which probably can't be as effectively treated with broadband absorbers like those you already have installed.

Your measurement software will help get you there-- a great tool. I hear fuzzmeasure is a good one; dunno, as I'm using SMAART 6.1.

I'm astonished the Church of Room Treatment's ministers have not already chimed in to help...


PS - that gear setup looks like it's going to be sweet....
Old 23rd December 2010
  #4
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Hey.

I want to congratulate you on a very good post! You are being very specific which helps alot when others try to help!!

So my ideas would be as follows.
your 65hz mode is caused by the width of your room. Play a sine at 65Hz and check around the room.
It should be loudest on the sidewalls, in the corners between side and front/back walls, corners between side and floor/ceiling wall!
It should also be very strong in the middle of the room from front to back!

Try to trap a few of these areas with as thick absorbers as you can! That should help a bit!

oh and ps. do what tonio suggested. If you want to compare if your treatment is helping, you will have to setup your graphs way better!
Old 23rd December 2010
  #5
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Thanks guys!
Quote:
Originally Posted by tonio View Post
Eddie, set up FM like this for better results on the waterfall.

Also appears you are not using the auto device correction due to the long delay.

That's great, i'll do that tonight!

Boschen & Nixoblivion, i can see the figure come up on the mode calculators, but have no idea why this particular mode seems to be kicking my ass heh. The calculators always come up 'green' and/or never highlight any issues. But today i'll definitely move some panels around to the side walls and see if i can budge that 64hz bump at all. I don't yet know anything about resonating or membrane panels to target specific areas...

That 90-100hz null was really quite bad (a narrow but extreme dip) before i started moving the panels around. But this 64hz bump is flattering everything massively.

Thanks for your comments, would appreciate some more!!

Eddie
Old 24th December 2010
  #6
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Hi guys

Playing a 64hz sine wave and walking around the room is really mad. It's also quite disheartening because of all the time and money i've spent building traps etc, and to have such a huge peak that i don't know how to fix. I added some of the panels from the back of the room, to the sides. I re-did some tests with the left speaker, and basically got a similar peak - do you think it's improved?. Obviously there are now some dips due to removing some panels from the back walls (i assume).

I think the peak is still peaking at the same value, but the rest of the graph seems to have shifted 'up', effectively meaning the peak has been reduced. Er, right?

Maybe i didn't add enough, but the side reflection points are over 8 inches, and i know the thin panels won't do much at 64hz, but i am not sure what to do at this point. I think raising the panels up off the floor will have them more central, and they could possibly be more effective at that height. Any suggestions are welcome!

I also have a graphics card glitch so i can't get the histogram to display without glitches. I think i need a new graphics card for my mac So i've put the graphic up 4 times, there's a glitch on each of them, but you should be able to get a good picture of things, overall.

I will also move the 7', 4" thick vocal panels to the sides and re-test to see if there's any change... obviously the response from the back of the room will degrade further because they're moved. Some more advice would be great!

Eddie

Edit: i removed waterfalls as they were glitchy. Please see correct ones attached at the bottom. Thanks!
Attached Thumbnails
Room analysis shows large 64hz peak - details + pics - any advice?-studio131.jpg   Room analysis shows large 64hz peak - details + pics - any advice?-studio132.jpg  
Old 24th December 2010
  #7
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Before and after frequency response graphs, after adding some extra insulation on the sides (shown in the pics above)

Old here
New here
Old 24th December 2010
  #8
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Seriously, your waterfalls are terrible :D
I dont know whats going on there, but there seem to be quite a few bugs and all!
What you need to do. Adjust the settings until you can see the lowest Freq. ring out (that will probably be your 65Hz. So in your case make the time longer (choose 500ms for instance). Then you will see how long that frequency is ringing!
Take a print screen of just the waterfall, so we can see it clearer.

Now the same with your frequency stuff. We are looking at modal work here, no need to attack the impuls response, especially not if your zoomed out THAT FAR! So just attach the freq. response and zoom in a little more (y axis), to show more detail.

But what i can tell your right now, the panels on the side have helped quite a bit already. If you can get a few more it would be better. Also as i said in my earlier post, have the 65Hz sine going and check where its really loud. then you will know where to treat!!

greets!
Old 24th December 2010
  #9
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Yes, my graphics card must be on the way out. OpenGL stuff makes it glitch like that. Hopefully though, you get the idea. I'll make those adjustments on the graphs on the next round of testing

I'm not sure if there's a more efficient type of trap or something i can build? At the moment, it looks like i'm going to have to lose everything from the sides and have 8" (or thicker) traps all along the side walls, which isn't really practical or in any way desirable for me! The 'office' machine gets a lot of use and i need that table there, or thereabouts.

Anyway, i'm sure everyone is busy with Christmas and doesn't want to worry about room modes and stone walls for a few days, so Merry Christmas and happy holidays to all!

Cheers

Eddie
Old 24th December 2010
  #10
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Quote:
Originally Posted by The Beatsmith View Post
i can see the figure come up on the mode calculators, but have no idea why this particular mode seems to be kicking my ass heh. The calculators always come up 'green' and/or never highlight any issues.
the 65hz is the 2nd axial mode and the problem is possibly the 32.5hz 1st axial mode and the very dense wall space you have - the S3A can drive that low pretty well and it will confuse the readings even if you don't see it on the chart. does the bass seem "oppressive" in the sense that you're driving the 65hz sine wave and yet there is no ability to localize it? you may need quite a bit more trapping in that room... a simple test is to bring in some bales of pink insulation and set them on the outside of the monitor stands and see if you get some relief.
Old 24th December 2010
  #11
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Hi!

What do you mean by localized? I can hear that it's at it's highest point in the center, then dies off as you get closer to the wall - then is loud again near the wall. I think this is similar to the 'axial' mode diagrams i've seen on the eigenmode calculator.

I will try placing some of the RW5/RS100 panels to the sides of the stands, and i'll see if that does anything.... I am unsure what pink insulation is!

Thanks!

Eddie
Old 25th December 2010
  #12
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what i mean, do you get a sense that there is other bass energy in the room but you cannot seem to identify it? i just had a problem like this a few months ago and it turned out to be way too little absorption in the high isolated room to treat the 32hz and it was really the very low end that was problematic and the resonances we were seeing higher were throwing us off. we ended up adding another 400lb or so of rigid insulation absorbers throughout the room, not just near the listening position. "pink" "yellow" normal wall insulation in a roll is pretty well compressed and is almost the right density. so if you don't have enough, it's easy enough to run over to the building supply and get a couple of rolls.
Old 25th December 2010
  #13
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Pressure like the attached?

To add to Glenn-65hz is the harmonic (fundamental 32.5hz) of width axial.
Attached Thumbnails
Room analysis shows large 64hz peak - details + pics - any advice?-screen-shot-2010-12-24-6.19.58-pm.png  
Old 25th December 2010
  #14
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The peak is one thing, but the nulls ( 90-120hz) your missing the bass gtr/body.

How does it sound-no low end / twangy?
Old 25th December 2010
  #15
jdg
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ceiling cloud stat.
cover your entire ceiling if you can
Old 25th December 2010
  #16
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Room analysis shows large 64hz peak - details + pics - any advice?

Quote:
Originally Posted by jdg
ceiling cloud stat.
cover your entire ceiling if you can
Hey John, how would this help my main issue when it's a width room mode? I will put a 2 inch cloud up above mix spot as I mentioned but as it's rented, covering the entire ceiling isn't really feasible. I don't see how it would help the bass? The ceiling's pretty thin anyways.

Cheers
Old 25th December 2010
  #17
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Room analysis shows large 64hz peak - details + pics - any advice?

Quote:
Originally Posted by tonio
The peak is one thing, but the nulls ( 90-120hz) your missing the bass gtr/body.

How does it sound-no low end / twangy?
Everything sounds quite flattered and smooth because of the huge peak. The nulls are worse because I took some traps from the rear wall and placed them on the sides to do some of the secondary tests that I posted pics of. To be honest I haven't done tons of listening to music because I know that what I'm hearing is so wrong. I don't really feel I'm able to work much like this.

Quote:
Originally Posted by tonio View Post
Pressure like the attached?

To add to Glenn-65hz is the harmonic (fundamental 32.5hz) of width axial.
Yes i think so, but i will do some more tests tomorrow. This was the diagram i was referring to.

Thanks & Merry Xmas!
Old 25th December 2010
  #18
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Quote:
Originally Posted by The Beatsmith View Post
To be honest I haven't done tons of listening to music because I know that what I'm hearing is so wrong. I don't really feel I'm able to work much like this.
Its not THAT bad actually. There have been way worse problems in this forum

But seriously, if you can put absorbers between floor and side wall you will probably get a lot better results than you have right now. If you can then also put some between side wall and ceiling you'll do great! This will help more than just putting absorbers against the whole side wall (or at least it will be easier and more efficient! )
Old 26th December 2010
  #19
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Room analysis shows large 64hz peak - details + pics - any advice?

Thanks!

What thickness are we talking for side panels? 4 inch RW5/RS100? Thicker? I read something about membrane traps being effective very low, and not having to be 10inch thick etc?

I'm severely restricted in drilling anything to the ceiling, but I'll see what I can do. I'll borrow a joist detector and see what I can see.

I'm going to take the other 4" 7 foot panel, and place them near the corner panels, on the side Walls. I'll also experiment with placing panels along the floor/wall corners. I'll see if covering all that area with 4" makes enough difference. Then I can have the wooden ones in front of them too, but more towards the side reflection points.

However maybe a 4" broadband panel doesn't go low enough to really make a difference on 64 - or worse - 32 Hz.

I'll report back after I put the 7' panels on the sides, but am interested in if I should just stick with broadband absorbers?

Thanks! Hope you all had a merry christmas/holiday.

Eddie

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Old 27th December 2010
  #20
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Hi,

I've spent all evening testing. I have put tried floor to ceiling (front wall) 8 inch traps, i've tried floor to ceiling on the side walls, i've tried nearly everything i can think of. 12" of traps on the side and in the corners, spreading a load of traps around the room on teh side walls, etc.

Changes are observed elsewhere, but nothing i do is taming that 64hz peak/bump.

If i put my head near that window on the left while playing a 64hz sine, the bass is outrageous. I've tried to trap it as much as possible but it doesn't have much effect. Putting traps along the floor/wall corner made no difference. Listening there, there does not seem to be more building than just the wall.

I would bore you all with the millions of combinations of things i've tried, then tested, then tried, then tested. But it's not really getting anywhere. Having 8 inch corner traps and 8inch side reflection points, with some 4inch traps all around the side walls basically has done bugger all to tame it.

I'm really desperate, can anyone suggest anything else? A different kind of trap?

Many thanks.

Edit: I also have some freakiness going on in other frequencies also. For example, around 160-170hz. If i am 30cm behind my realistic mix position (earlier, i had the mic about 30cm behind where i'd realistically sit), there is a 10-15db drop in the level of this frequency. However sitting in the 'realistic' mix spot creates a null at around 130hz, as you can see in the freq plots. Here's a waterfall plot of the left and right speakers with my current setup, which i've set back to 'normal'/before as all the changes i made didn't do much
Attached Thumbnails
Room analysis shows large 64hz peak - details + pics - any advice?-freq-left.png   Room analysis shows large 64hz peak - details + pics - any advice?-freq-right.png   Room analysis shows large 64hz peak - details + pics - any advice?-waterfall-left.png   Room analysis shows large 64hz peak - details + pics - any advice?-waterfall-right.png  
Old 27th December 2010
  #21
SAC
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Just a quick comment.

64 Hz is almost 17.6 feet long! The quarter wavelength is almost 4.4 feet!

Are we really expecting a 4" broadband trap to do anything to this? Heck, my guess is that the 4' trap is not even large enough (not in thickness, but in the length and width as most are made only 2'x4' based upon the commonly available panel size!) - at least 4.5 feet in any dimension - to even be 'seen' by the energy! So in noting that a 4" broadband trap positioned to minimize early reflections is not particularly effective in mitigating the mode - are we, or better, should we be surprised if it is not as effective as we might wish??? heck, i would literally be Amazed if it was effective!

And a 8 " corner trap, even straddled and moved out, say, 20 inches from the wall is going to be minimally effective.

So, before you just busily rearrange everything and try everything you have, stop for a moment and think of the SIZE of the wavelength at issue and what you have with which to treat it! And THEN remember that you can optimize your efforts by mapping the distribution of the behavior and placing traps in the regions o maximum velocity and/or pressure depending upon the traps employed.
Old 27th December 2010
  #22
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Hi SAC, thanks for replying.

I've just been following what i've been advised to do so far. I've mentioned that i don't think that 4" broadband traps would be thick enough, but don't currently have any alternatives that i'm aware of. I've placed 8" traps, even 12", to the sides while there's 8" in the front corners, and conducted all manner of tests. I've actually used some 7', floor to ceiling traps at the side (4" thick), then put 2 2'x4' panels (also 4" thick each) in front of that, so 12inches at the sides, 4inches in the front corners, and other 4inch panels along the wall. Made it come down a db or two.

As i stated, i thought i perhaps need to build a membrane trap - is this more likely the case?

"And THEN remember that you can optimize your efforts by mapping the distribution of the behavior and placing traps in the regions o maximum velocity and/or pressure depending upon the traps employed."

Surely i have been placing the traps in regions of maximum velocity/pressure, and doing the best with what i have, however they are simply too thin/ineffective for such low frequencies?

And if this is the case, what kind of trap or alternative could you think of that might help?

I would love some concrete advice, if you have any based on the information at hand. If you need any more information, please let me know.

Many thanks

Eddie
Old 27th December 2010
  #23
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64 Hz? Do a search here for the BBC Type D2 and BBC Type A10 if you want to DIY. See RPG Modex Corner and Modex Plate for a safer solution. Not cheap, but thats that. Making tuned absorbers by yourself can be quite frustrating. I don't think porous absorption is effective at handling specific modal issues without taking away half the space available to you. Good luck.
Old 27th December 2010
  #24
Gear Guru
Whoa...

Beatsmith. With respect, I am seeing here, an information overload at the bottom of a learning curve here. Let's add in some faulty equipment or software and, well, some confusion may be expected.....


Some of the Waterfalls look somewhat credible. In my opinion not too shabby either. Never seen a pretty one.
I am uncertain as to what is causing the 65Hz bump. When I speak of playing sines and all of that, the game is to positively identify the mode.
A second width will have a peak at the centre, and at the walls, but it will also have nulls. The pattern will uniquely and positively prove which peak is in action. The tangential at 69Hz may make this process difficult. Tune very carefully. SignalSuites is very good. Identify both and make a mode map. It may be quite difficult isolate the 65 and 69 but you need to. That close, they can start to work together and 'blend'. Masking tape on the floor is useful. Sound Levels at the peaks and nulls are useful to prioritise.
When you have utterly proved the source(s) of the 65Hz bump, only then start to plan treatment.

So if it is mostly the width/65-
You would need to go 300mm or more with a similar or larger airgap to hit this frequency well. You will also need a decent surface area as SAC has said, although note the very different views on thickness needed. For more on thickness and airgap, read Q4Avare.
The performance of these side panel/gap devices can be significantly enhanced by spraygluing FRK on the back.
A perforated system, tuned to 65 Hz may be the best option. You will need to position these carefully or include a HF killing front layer to maintain your RFZ. Take a look at JohnlSayers.com for angle slatted ideas here.

Moving to the Tangential 69. Take a look at hunecke.de | Room Eigenmodes Calculator
This will show a build up in the corners, SuperChunks or Modex. There is also some other interesting info. The centres of the side walls are areas of High Particle Velocity, Low Pressure, absorption works there too, thus the 65Hz treatment would do double duty. Also the front and back walls have action.


DD
Old 27th December 2010
  #25
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Hi Dan Dan, thanks for your reply.

Yes, i know there's a lot to take in both for me and anyone reading this, but i was just trying to provide information that i was inevitably going to be asked. I also apoligise the issues with my waterfall plots, however i have now fixed the problem of the glitches by transferring the FuzzMeasure file to my laptop and screenprinting from there. As you can see in the last ones i posted, there are no issues with glitching. I think the latest freq/waterfall plots are 'safe' to look at as i now understand how to display them.

With regards to the 64hz bump, i have said that i can hear that it reacts identically to the eigenmode diagram for that mode, which shows high pressure at the walls and center, but nulls in the side 'thirds'. What i will add is that in the 'middle' of the room (both length and width ways), it cancels out and gets light.

I will also try to observe the 69hz issue and have neglected it a little. I am able again, to see patterns in the distribution similar to eigenmode diagram. I have noticed that on the front wall, in the middle, there is a build up when i play the 64hz sine, which could be to do with the 69hz issue. I am able to change this 69hz bump slightly with front/backwall absorbsion, but it obviously doesn't do anything with the 64hz.

I appreciate your help on the thickness etc required. I will have to look into these new types of traps. However due to the nature of the stone wall to the right of mix position, it would be very difficult to 'flush fit' a panel to the wall. And the window bay on the left is quite problematic too.

I am open to the idea of superchunking the corners and using the current front corner traps elsewhere. I'll have to look into the threads on the effectiveness of straddling panels as i currently have, vs superchunking.

I will also read the Q4Avare thread. I've looked at it a few times, but some of it was a bit complicated for what then understood. I'll have another go at it now.

Thanks again for your reply and sorry for any confusion.

Eddie
Old 27th December 2010
  #26
Gear Guru
Weeding

Hi Eddie.
Quote:
With regards to the 64hz bump, i have said that i can hear that it reacts identically to the eigenmode diagram for that mode, which shows high pressure at the walls and center, but nulls in the side 'thirds'. What i will add is that in the 'middle' of the room (both length and width ways), it cancels out and gets light.
No comprendo amigo. 'High pressure at the walls and centre' and 'cancels out and gets light in the middle of the room' seems contradictory.

DD
Old 27th December 2010
  #27
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I too am a little confused by it but i hope i can clarify, as i just re-tested. I think it 'sort of' makes sense because the walls do not run the entire length of the space! Some notes:

- When playing a 64Hz wave the side walls exhibit a lot of energy, which lessens as i move towards the back of the room.
- There is a central boost along the length of the room, which is strongest at the front wall, then as you move towards the back of the room it lessens. In fact as i'm at the end of the coffee table, around 475cm back (2/3 back into the room) the intensity decreases quite a lot), but then the walls basically end not far from there! If i go to the back wall and put my ear to it, there is some build up there.
- Around mix position, the 'eigenmode calculator' pattern seems to be correct,

The peak seems to be strongest in between the speakers/front wall, and lessens as you move back. Remember the side walls do not run the length of the space!

I'm going to play a 69hz tone and listen to see what i can hear.

Many thanks

Eddie
Old 27th December 2010
  #28
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When playing a 69hz tone i get quite a different response, and it's not what the mode calculator displayed. For example in the front corners, the sound actually vanishes, and is not more intense. It is more intense at the middle of the side walls, and in the middle of the room. It is also very intense at the front wall, between the speakers. This is where it is the most intense.

I would say it stays quite consistent along the walls and center, more so than 64hz.
Old 27th December 2010
  #29
Gear Guru
Convinced

Eddie, that is clearing up for me now.
Just a couple of points which might kick this in goal.
The actual numbers of the frequencies on a Waterfall are not meant to be taken too literally.
The same may be true of Signal Generators. As I say, Signalsuite is good, I tested it.
Modecalcs need good dimension measurements to work well.
If you have a concrete room, the real modes will be very close to predicted.
If you have drywall and insulation lining a wall, where is the real boundary?
You might have to guesstimate here to get a more useful result.
Are you checking vertically? Does the action get stronger at the floor and ceiling or that their corners with the walls?

Both modes (or maybe even more of them) appear to be strong at the sidewalls, which appear to be very solid, or one of them in any case. The action increases towards the front, makes sense, more enclosed. The pressure at the back is probably being alleviated by the sudden loss of side wall. A Sound Level Meter, even a cheap one, or even a meter in a DAW are very useful to prioritise things here.
e.g. is 65 Hz louder at the corners of the front wall or is it a whole wall thing?
69Hz corner levels?

Presuming that both are strong, then more bigger corner traps seem like a good idea. The 34 inch wide Superchunks are very much more powerful than the 24, but they do consume a multiple of the fibre and cost.
You could fill behind your existing ones with attic insulation or 'nested' panels. See studiotips - tips on studio design, acoustics, and wiring
You could attempt to build or buy enhanced corner traps.
e.g. MegaTraps, MaxTraps, Modex, or a tuned corner perf design.

Similarly the side treatments may be simply not enough. Your room is big.
Your current observations are strongly suggesting perf tuned broadly 60-75Hz

Irrespective of all of that, you definitely need a Cloud. Hilti and other plastic sheetrock plugs with wings are well capable of supporting normal clouds. You don't need to find the studs, but do avoid the wires when drilling.

DD

DD
Old 27th December 2010
  #30
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Quote:
Originally Posted by DanDan View Post
Signalsuite is good, I tested it.
Thanks, so far i've been using Logic's test oscillator. I'll give this a whirl.

Quote:
Modecalcs need good dimension measurements to work well. If you have a concrete room, the real modes will be very close to predicted. If you have drywall and insulation lining a wall, where is the real boundary? You might have to guesstimate here to get a more useful result.
Good point, duly noted. The room is probably half a foot wider or so.

Quote:
Are you checking vertically? Does the action get stronger at the floor and ceiling or that their corners with the walls?
Indeed i am. With 64hz, there is no appreciable difference at the top and bottom corners that i could measure or hear.

Quote:
A Sound Level Meter, even a cheap one, or even a meter in a DAW are very useful to prioritise things here. e.g. is 65 Hz louder at the corners of the front wall or is it a whole wall thing? 69Hz corner levels?
I've been using my iPhone4 DB meter app 'Decibel'. I know that this will be restricted by the limitations of the mic, however it seems to be surprisingly accurate in terms of reflecting changes in intensity. I've tested playing the 64hz tone, and at the side walls, corners, mix position, the signal is at around 65db. In the 'nulls' either side of the speaker stands, it drops to around 45-48db. On the front wall between the speakers, it pretty much hits 70db.

69hz (same output level) i am getting 60db at the mix position and side walls, 50db in the corners and nulls, and 65db in the middle of the front wall. I am being given my friend's 'proper' db meter, i'll have it tomorrow.

Quote:
Presuming that both are strong, then more bigger corner traps seem like a good idea. The 34 inch wide Superchunks are very much more powerful than the 24, but they do consume a multiple of the fibre and cost. You could fill behind your existing ones with attic insulation or 'nested' panels. See studiotips - tips on studio design, acoustics, and wiring. You could attempt to build or buy enhanced corner traps. e.g. MegaTraps, MaxTraps, Modex, or a tuned corner perf design.
I am very interested in attempting superchunks as i think this would be the most cost effective solution, however i haven't done the maths on how much it'd cost to fill the front two corners. The 34inch would actually take up less room space than the current ones do anyway. Filling behind the current ones is also an 'easy' fix/boost. I saw the modex link - however they seem to be US based and very expensive, especially for shipping.

I will add that when trying 8inch floor to ceiling corner traps, there was no real difference in the 64hz bump.

Quote:
Similarly the side treatments may be simply not enough. Your room is big. Your current observations are strongly suggesting perf tuned broadly 60-75Hz
Indeed, as i mentioned i have tried putting a LOT of traps on the side, and it has hardly budged such a low frequency. I will have to research 'tuned' traps.

Quote:
Irrespective of all of that, you definitely need a Cloud
Yes, i intend to have two 2'x4'x2" panels above mix position. Just waiting on more RW5 to come along as it got held up by the weather/xmas.

Thanks again, i will begin to research how on earth to go about creating tuned traps, on the John Sayers forum. I posted this question there but did not receive a response yet Given my current knowledge however, i believe many of these use principles which rely on the trap being flush and firmly fixed to the wall, which i wouldn't be able to achieve here. I will keep reading.

Thanks,

Eddie
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