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Post by Hexspa on Apr 28, 2017 17:51:52 GMT
Good advice from Nigel.
You can also search the forum for "flat gap method" to see how I hung my panels vertically.
-m
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Post by rock on Apr 30, 2017 21:10:38 GMT
Exactly! I suggested spacing your panels off the wall because it seemed it may be the easiest, not because it was the most effective. Traps in the corners along the side walls and the ceiling are generally more effective. For those use FRK facing the room. Nigel and Hexspa are correct that it's not easy but without sufficient bass trapping it's even more difficult! A demonstration you can do is to manually sweep a sinewave and you'll notice the level change. Set it at a given freq. say, 100Hz then walk all around your room and you'll notice it's different from spot to spot. The idea is that since the peaks and nulls are caused by room modes, eliminating the room modes would eliminate the peaks and nulls. OK, so you're not going to eliminate the modes, so you do the best you can to minimize them. Corners are places where 2 or 3 boundaries come together so you get more "bang for your buck" when you treat there. Another thing you may want to do is to verify the freq response of your speaker(s) at the typical distance of 1 meter. Test them one at a time (not both together... you probably only need to do one but since you'll be all set up, you might as well test both...just to see how well matched they are). The best place to do that is actually outside if it's quiet. Even better if you're on a slope so the ground falls away and will not interfere (much) with the measurement. As you should probably know/assume/guess, outdoors is the approximation of an anechoic environment...or vice versa Cheers, Rock
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Post by rock on May 1, 2017 21:57:21 GMT
Yes, but in the corners first then more on the ceiling, sidewalls and backwall.
The following has been repeated here many times:
A rectangular room has 12 corners not only 4. To reduce room mode peaks, nulls and modal ringing, treat as many of the 12 corners as good as you can. Wideband absorbers on the flat walls and ceiling help too, but since corner traps are built with FRK, paper or plastic facing the room, they are more effective bass traps while at the same time, reflecting some mids and highs (which is not what you want for RFZ absorbers).
Cheers, Rock
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Post by rock on May 3, 2017 18:46:17 GMT
Yes, and as many other corners as you can fit them. Since you are handy with REW, you can test as you go. Don't worry about RT60. See recent threads re. this subject.
Yes, paper or thin plastic sheeting lightly spray-glued, yes, before fabric. No, not if it is acoustically transparent fabric...which it should be.
Symmetry is not that important for bass traps just do the best you can. As long as they are not in the path to cause a reflection from the speakers to your ears, you are fine.
Cheers, Rock
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Post by Hexspa on Oct 19, 2017 19:12:23 GMT
Ya man, looks good. You can definitely work in that room. If you want to improve further then lower the min value of your waterfall to more clearly identify your ringing. Your SPL is sorted but the ringing is the last emperor, so to speak. Good job.
Thanks.
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Post by Nigel Spiers on Oct 19, 2017 20:30:33 GMT
Hi Pasim,
That's a great result - congratulations.
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Post by Hexspa on Oct 20, 2017 7:59:34 GMT
Ya man, looks good. You can definitely work in that room. If you want to improve further then lower the min value of your waterfall to more clearly identify your ringing. Your SPL is sorted but the ringing is the last emperor, so to speak. Good job. Thanks. Now its showing 65db so 5db more then enough Hopefully, I didn't make it sound like I'm crapping in your garden. It's just that I know all too well that further improvement is always possible. If I can issue you a challenge, go ahead and analyze your waterfall for decay rates. That's something I did in my most recent room thread. My targets were +-10dB SPL within the broadest spectrum possible and 20dB decay within 150ms above 40Hz. Should you choose to accept this mission, just open up your waterfall, ID potentially problematic frequencies, set the rear reticle at those peaks then drop your low display limit parameter 20dB down from there. You'll be able to see exactly how long each frequency range takes to decay. The spectral decay display also helps a lot with this. Of course, I don't know if you're interested in that level of detail but I feel it helps to know what your treatment efforts have and have not accomplished as well as exactly how well your room is performing and where. The downside is that, as soon as you add and/or subtract objects from a room (or open and close doors), the response changes. And ya, maybe I'm reading your graph wrong but it looks like you've achieved that target and have even done better in most ranges. I'd like to know the details, though Hope that helps.
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Post by Hexspa on Oct 21, 2017 8:00:55 GMT
I apologize. I read the graph wrong initially. I just couldn't believe you went from waterfall flood to incredible response so fast. Maybe I need to drink more Jager Congrats.
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Post by Hexspa on Oct 21, 2017 18:03:13 GMT
Thx man! Now i also feel that bass sounds about the same where ever i am in my room. It wasn't the case until i flipped my focal twins to vertical position and did some little placement adjustments. Didn't add any more treatment(hard to fit anymore anyways , well couple places i could). So those focal's clearly work better on vertical position in my room.. I've been thinking about your results. It really surprises me that the result is so good for the room's size. The six-inch panels surely have a lot to do with it, besides placement. The panels in my room are only four-inch. The whole thing has me thinking someone could get amazing results in a cube-shaped room with eight-inch panels everywhere.
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Post by Hexspa on Oct 22, 2017 5:31:09 GMT
I've been thinking about your results. It really surprises me that the result is so good for the room's size. The six-inch panels surely have a lot to do with it, besides placement. The panels in my room are only four-inch. The whole thing has me thinking someone could get amazing results in a cube-shaped room with eight-inch panels everywhere. My whole front wall is covered with 6inch glass wool (fluffy stuff) then those wood slats pretty big ones. Then on front wall corners there are corner traps from floor to ceiling, as you see on that picture i posted time ago. But those didn't alone provide me results i wanted. As i said i been adding stuff in whole summer. I also made another ceiling cloud and made thicker the one i already had above my desk, its now 10,3inch thick. 10" thick fluffy or rigid? Also with the corner traps - are they triangular "super chunks" or "angled" rigid panels? If "super chunks" then fluffy or rigid? How wide? Maybe I missed the details in this thread. Another question I have is what is the gray material that's on your walls? Is that thin absorption? What is your ceiling made of? Is it drywall? Are your six-inch gapped panels also fluffy? The fact that you've used six-inch fluffy (and not a minimum of 8" which is often recommended) and have gotten such good decay fascinates me. Then again, you did say you increased the thickness of your cloud 60% and got better results. One detail about your room I find interesting is your dimensions. Whether or not they're a golden ratio I don't know but they are relatively staggered i.e. they are 10.8' x 15.4' x 8.5'. Since your room is smaller, it would seem those smaller offsets are more significant than they'd be in a larger room. They're ratios so the values expand with size. What I'm saying is your room isn't 10x15x8 which I'm guessing would be worse for modal distribution besides providing less volume. I mean, your room is just shy of the 1500ft3 target for "vocal production" (no sub-bass) according to BBC white papers. Ethan has also mentioned that rooms of that size can produce good results. This is just the first time I'm seeing it first hand. Another crucial question is how is the performance in a 1' radius? You said that small mic movements make a big difference. It could be that larger rooms are more tolerant of positioning but I'm not sure. I've found it difficult to accept being 100% honest with myself about how good my room actually is. While I have measured my LP in a 1' radius, I have never actually tested my "recording zone"! I just don't even want to know! Regardless, this is just a revelation for me because I was previously under the assumption you needed a bigger room to achieve results like yours. If I can work in a smaller room then I have a lot more flexibility as to where I can live and thus spend on rent. I'll review this thread but it would be awesome if you wrote a summary or provided me with details so I can make a video or something as a case study.
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Post by Hexspa on Oct 22, 2017 16:17:59 GMT
Thanks for the response, pasim. I'm going to have to return to this but I want to let you know I got your reply. This is some interesting stuff! Never have I ever seen a listening room "evolve" as yours has.
The idea about measuring the radius is pretty foundational, apparently. It comes down to having a good place to listen within a given area - something like 0.9x the distance your speakers are from each other (and the center of the LP is from each speaker). So, measure how far apart your speakers are then take measurements within that radius from the center of your "triangle". Or you can just use 1'. The former metric is from an EBU paper I just glossed over. I'm going to post about that now in a new thread.
Thanks.
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Post by Hexspa on Oct 26, 2017 18:29:26 GMT
Hi, pasim. I'm very interested to see your room's measurements in a 1' radius. It would be great to save a few hundos in rent until I can buy something.
Thanks.
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Post by Hexspa on Oct 26, 2017 21:20:55 GMT
Hi, pasim. I'm very interested to see your room's measurements in a 1' radius. It would be great to save a few hundos in rent until I can buy something. Thanks. Ok im gonna measure when i have the time. Just to be idiot sure, its just going 1foot for every direction from listening position ? Yes. It's what any self-respecting Acoustician would do . I didn't want to use the "I'll show you mine" bribe but, suffice it to say, I have done this. This procedure is at least important to 1. Be realistic about the room's performance (not doubting, just saying), 2. Reveal which band, Q and amount of EQ to implement, if you so choose to use corrective EQ below 150-300Hz, 3. You might find a better LP, 4. ? ? ?, 5. Profit. What especially intrigues me is how much variance there will be in a smaller room vs a larger one. Of course, we have different amounts and kinds of treatment but maybe some comparison can be drawn. Regarding #2, your SPL response is pretty flat but you might be interested in finding out how much variance there is within a normal span of movement. Like Ethan's cartoon shows, even an untreated room can exhibit flat SPL response within a 1/4" radius; just clamp your head in a vice! Like I mentioned in the EBU post, this rabbit hole is deep. It's almost as if physical acoustics is a dominatrix and we're just casual clients: we get a lot of satisfaction out of basic efforts but that doesn't mean we're fully in charge. NON FUNNY EDIT: So I've been measuring in approx. 1' radius as per Ethan (IIRC). Not "every direction" (as a radius has infinite points) but I think 1' center, forward, right, left and aft will do. However, if you want to get super anal (who doesn't?) then the EBU recommendation is for a listening radius of 0.9x the distance between the stereo speakers. That is, of course, if IIRC. (Always use an IIRC disclaimer ) Basically, use 1' for easy mode and 0.9xdistance of stereo speakers for hard mode. Please understand that I'm being as respectful as an ass like me can. I love your results and I dearly hope I can achieve them. Especially in what's considered a "small room", you have effected enormous improvement. Decay seems to be the granddaddy of measurements: can decay vary in different positions? Doesn't seem so but I haven't verified. My whole inquisition is about being able to achieve your measurement in that size of a room. If it's feasible and consistent around the room then it's worth learning everything about what you've done and making that information and procedure available to the internet. Maybe I'm blowing this out of proportion but, I repeat, I've never personally seen this so I'm inspired. Cheers 🍻
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Post by Hexspa on Nov 1, 2017 19:57:10 GMT
Man, that's incredible.
I've read through this thread a few times but, what would you say made the biggest difference? One day, I'll have to go through and take notes on what you've done. Your super chunks are rigid, I remember. Again, this is exciting news and I can't wait to try some of your implementations for myself. As far as the decay goes, I assumed it wouldn't change much. It doesn't make sense to a layman like me that decay would change like SPL based on position. Once a sound is gone, it's gone, right?
Good job man.
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Post by Hexspa on Nov 5, 2017 15:58:25 GMT
Hey, pasim: do you have a youtube channel or website I can shout out if I make a video on your room? I'm not guaranteeing I'll do a video or that it'll help either of us at all but I'd like to repay you for providing such a great example of what's possible with a little thought, time and effort despite what the establishment would have us believe. Also, do you mind if I use your pics and graphs to help illustrate the point?
Thanks.
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