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Post by patate91 on Jul 17, 2018 14:36:48 GMT
I ordered a pack of roxul comfortboard (2"x36"x48") yesterday, so I'll have to wait 1 or 2 weeks before I can experiment.
I re-read an Ethan's article and I'm puzzle if it's better to do several panels or less panels but thicker.
I think there's six panels in a roxul pack so I can do 12 2"x36"x24" or 2 4"x36"x48".
I already have 2 thick panels on ceilling and 4 in corner. Walls have foam as temporary solution. Note this is for a listening room.
What's your thought about that?
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Post by Deleted on Jul 17, 2018 15:10:04 GMT
Better to do more panels, and get more surface area covered!
I think that's what Ethan recommends too.
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Post by Michael Lawrence on Jul 17, 2018 16:34:43 GMT
Patate91-
Welcome. Depends on what you're trying to accomplish. General taming of reverberant conditions benefits from as many square feet of absorption as possible.
If you're concerned with specific early reflections, you want to cover specific locations. The thicker the absorption, the further down in the frequency range that treatment will be effective. For early reflections in particular, getting down to 125 Hz isn't the goal and reflections aren't specular (bounce like a laser beam) that low anyway.
If your goal is bass trapping, treat the corners and go as thick as possible.
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Post by patate91 on Jul 17, 2018 16:50:21 GMT
Bass is pretty good now, so I'm at guetting rid of reflexions.
Yesterday I tested with spleeping bags and kids and correcting early reflexions improved bass a little bit more.
I currently have a superchunk bass trap in one corner only. Adding stuff in other corners never gave me good results. Note that my room is "L" shape with stair case. Another thing is that I only need to correct acoustic for my listening spot only. My wife doesn't care about audio and kids are too young too.
I'll post some pics and graph later.
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Post by patate91 on Jul 17, 2018 16:53:33 GMT
My superchunk corner is made with 4 - 4"x24x48" comfortboard panels. I put laid them on the flour on the corner next to the couch. Speakers are pretty big and close to corners. I experienced a lot with speaker placement and I think I get the best balance I could get.
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Post by patate91 on Jul 17, 2018 18:46:24 GMT
Here's my room. Note that my drawing is not scale, but it's pretty close. The big X is where is sit. It's centered between speakers and speakers were aligned and toed in with a laser level Location : Basement Treatment : 4 panels in the corner next to the couch. There is a pile of cushions on top of it and a DVD rack on the wall. 2 panels on the ceiling. For now, egg crate foam on walls at first reflexion points and on the door next to the couch. A bed cover on a curtain rod on the back wall. It's easy to remove since we see this part when I enter the house. A pillow at first reflexion point on the aquarium. 4 big chair cushions between right speaker and wall. 3 bean bags in the corner behind left speaker. Audio rack is full of audio gear, CD and LP. It is the same height as the speakers (16'' woofer + comp driver and wood horn) Shag carpet, and I put kids foam mat under it (puzzle shape) to cover the entire floor between couch and speakers. Like I said earlier there's still a lot of place where I can add panels. I tried to place panels and fiberglass pack and it didn't give me good results (freq, impulse, decay, etc). I marked in red where I'll add the next panels. Sleeping bags gave me good results on bass, mid. Impulse a lot more cleaner. Back wall is challenging to treat since there's stairs ( above the aquarium too), and this is what I see when I enter the house. The distance between back wall and seating spot is ~101''.
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Post by patate91 on Jul 17, 2018 19:00:54 GMT
These are old measurement from september 2017. I'll do new measurements when I'll get my new panels. No smoothing, Blue door next to couch open, Red door closed Impulse, yesterday I got higher peaks, that first I can removed easily at firts reflexion points. Egg crate foam is not a good solution, my sleeping bags setup gave me similar results RT60
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Post by patate91 on Jul 17, 2018 19:02:50 GMT
Waterfall Note that the 60 hz decay is no more present. kids were in the house when I did most of my measurements. But it gives a good idea on what it lokks like right now
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Post by Hexspa on Jul 17, 2018 19:17:15 GMT
Hi patate. Your measurements look good to me. Pasim is right regarding Ethan's findings and Mr. Lawrence gave you specifics. What are you trying to accomplish?
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Post by patate91 on Jul 17, 2018 19:29:44 GMT
I want to gwt the flatest response I can without EQ.
My next move will be a minidsp to get an active crossover. The current one cross at 800hz and horn can go to 600hz. I then plan to use a little bit of EQ to get the maximum out of my room and setup.
I'm having fun doing this and i learned a lot about acoustic.
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Post by Hexspa on Jul 17, 2018 22:46:20 GMT
I want to gwt the flatest response I can without EQ. My next move will be a minidsp to get an active crossover. The current one cross at 800hz and horn can go to 600hz. I then plan to use a little bit of EQ to get the maximum out of my room and setup. I'm having fun doing this and i learned a lot about acoustic. Ok, so you're a geek lol. I say that lovingly, as a geek myself. No shame there, brother. 'Minidsp' sounds like you're into hifi. We're officially out of my knowledge garden. Even so, maybe I can squeeze some relevant juice out of my lime. Please season my advice with a grain of salt.
Two things come to my mind regarding your situation and they are: positioning and decay time. Positioning affects your SPL response and a short, evenly-tapered decay time might be more important than a flat SPL response. I looked at your room graph and I believe you can improve your layout. If you haven't heard of the 38% rule then check it out. If you have heard of it then maybe it's time to revisit the basics.
There's no doubt that additional absorption will help you with decay. The problem arises from the fact that broadband absorption gives diminishing returns. If you're in a permanent facility then you can consider resonant absorbers to optimize your decay. As per this forum's status quo, you should only deploy this option only after maximizing your broadband effort.
Lastly, I heard you say that superchunks don't give you a positive benefit. I'm going to disagree and postulate that you either A. didn't put in a great enough quantity or B. didn't experiment sufficiently with their placement. In my room, I have 9 4'hx31.5"w superchunks and they form the basis of my bass management. The front 4 are spaced off my corners about 2.5' and have rigid angled panels angled vertically and leaning against the corners behind them. I actually took measurements of several panel-chunk arrangements in this room before settling on this current one. Like Ethan and Yngwie say, 'more is more '- more absorption and more experimentation.
Hopefully this helps.
Peace.
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Post by patate91 on Jul 17, 2018 23:01:29 GMT
Ok, so you're a geek lol. I say that lovingly, as a geek myself. No shame there, brother.
'Minidsp' sounds like you're into hifi. We're officially out of my wheelhouse. Even so, maybe I can squeeze some relevant juice out of my lime. Remember to season with a grain of salt:
Two things come to my mind and they are: positioning and decay time. Positioning will help with your SPL response and decay time might be more important than a flat SPL response.
That being said, I looked at your room graph and I believe you can improve your layout. If you haven't heard of the 38% rule then check it out. If you have heard of it then maybe it's time to revisit the basics.
There's no doubt that additional absorption will help you with decay. The problem arises from the fact that broadband absorption gives diminishing returns. If you're in a permanent facility then you can consider resonant absorbers to optimize your decay. As per this forum's status quo, you should only deploy this option only after maximizing your broadband effort.
Lastly, I heard you say that superchunks don't give you a positive benefit. I'm going to disagree and postulate that you either A. didn't put in a great enough quantity or B. didn't experiment with their placement. In my room, I have 9 4'hx31.5"w superchunks and they form the basis of my bass management. The front 4 are spaced off my corners about 2.5' and have rigid angled panels angled vertically and leaning against the corners behind them. I actually took measurements of several panel-chunk arrangements in this room before settling on this current one. Like Ethan and Yngwie say: more is more; more absorption and more experimentation.
Hopefully this helps.
Peace.
Decay time is ok now, as I said this is old measurements and kids were in the house, doing thing kids do like jumping and screaming lol. I always try to start it when no one is moving. When everyone are out, there's nothing at 60hz. As for superchunk, I'm limited by space and size of speakers. I tried to place as much as I can acoustic panels in corners behind speakers. As I said it get the spl graph worst and the effect on impulse and waterfall were not that good. I also tried with a pile of cushions, pillows, spleeping bags, bed cover, fiberglass pack etc. on every corner of the room. I even move the 100 gal aquarium lol. But anyway bass response is pretty good now. I'll do an other set of tests once I get the other panels. There's dips above 250hz that I can certainly removed with broadband panels (I guess)
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Post by patate91 on Jul 17, 2018 23:02:19 GMT
Ho and yes am a geek lol (perfectionnist too).
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Post by patate91 on Jul 17, 2018 23:16:53 GMT
For speakers placement I did some tests for at least 2 or 3 days. I tried a lot if configurations.
I think the fact that there's only one speaker in a solid/cement corner it change how both speakers are behaving in the room.
Behind the "superchunk corner" there is a storage full of stuff, under the stairs and split level.
All other walls are gyps with more or less thing behind.
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Post by Michael Lawrence on Jul 17, 2018 23:57:37 GMT
Patate91-
I see that you're using REW. When you take measurements, you can set the software to take multiple sweeps per measurement. This is useful in a noisy environment (usually by "noisy" we mean HVAC but screaming kids count, too) because the test signal will sum coherently and the noise will not, so the signal-to-noise ratio of the measurement is increased. It's basically a mathematical way of lessening the impact of noise on your measurements.
That being said, your data looks very good indeed. You're doing very well for a room of that size, far better than I would have expected based on your description. With the exception of the 68 Hz issue, your room is basically +/- 5 dB in the "modal" region (below Schroeder, if you're reading up on acoustics) so I think you should feel somewhat successful already.
Really tough to tell given the available data, but I have a suspicion that the 68 Hz cancellation is an axial mode between the floor and the ceiling. If this is the case, it's going to be at ear height regardless of where you sit in the room, and I don't think there's much to be done about it.
You can try to knock a few dB off the depth with some bass traps IF that's indeed what the issue is.
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