Wich size for panel absorbers and hangers

Hello to all. I'm writing here because I have specific questions. I'm about to start the sound treatment to my studio and I want to begin with low frequecies panel and slat absorbers and build mid and hi absorbers as needed. I prefer this aproach, low treatment before and mid-hi later, as needed because I dont want to put too much hi absorption and have the room too dead. What I need to know is what could be the size of the panels and thickness/depth of the panel and what size for hangers. I want to control frequencies below 200Hz (I'll build slat resonators to control above that). Is there any calculator to tune a panel to a specific freq, like we do with the slat calculator? Thanks to all you guys.

Wow!!!! :? Well, I mesured the studio walls and did the room mode calculation with the Room Mode Calculator. These are the modes for lenght: 39 78 117 156 195 234 273 312 351 390 429 468 These are the modes for width: 56.3 112.6 168.8 225 281 338 394 450 506 How should I deal with this modes? what kind of absorbers? Thanks a lot. Ed.

AudioMedios wrote:

Hello to all. I'm writing here because I have specific questions. I'm about to start the sound treatment to my studio and I want to begin with low frequecies panel and slat absorbers and build mid and hi absorbers as needed. I prefer this aproach, low treatment before and mid-hi later, as needed because I dont want to put too much hi absorption and have the room too dead. What I need to know is what could be the size of the panels and thickness/depth of the panel and what size for hangers. I want to control frequencies below 200Hz (I'll build slat resonators to control above that). Is there any calculator to tune a panel to a specific freq, like we do with the slat calculator? Thanks to all you guys.

Perdon que interrumpa, puedes visitar este tema: http://www.johnlsayers.com/phpBB2/viewtopic.php?t=4581 Aqui mismo, Saludos!

I've been reading the posts about bass panel construction by Ethan Winer, I also read his articles on his websites. I can see there is a polemic about Ethan's aproach to handling bass frequencies and John's. Basically it's panels vs hangers/slats. I think both are ways of doing the same thing and maybe combining both is the key to a better sound treatment. I'd like you to advise me about this: Low frequency abosrbers in the corners of the room. I can't build the panels over the wall, they have to be portable. I'm thinking in putting 15mm plywood in the back of the panels, in the front there will be 1/4" plywood for deep-bass trap and 1/8" plywood for high-bass trap. Of course everything will be airtigh and the fiberpanel will be in the center leaving air gaps in each side acording to Ethan's plans. Is this OK? Hangers in the back upper side of the room (where the ceiling is higher) I have a space 1.40m High, 1.90m wide and 60cm deep to place hangers. How can I make a broadband bass absorber? I think all hangers could be 1.20m long and vary the width and thickness. What do you think? In the rest of the room I can put high absorbers, a pair of big clouds in the ceiling over the drums (the floor has light weight carpet over floating floor). As I said before treatment of low and low-mid is the key to tame a room, high frequencies are much easier to treat with foam panels or low density fiberglass panels. Tell me please what do you think. any advise will be really apreciated. Ed.

Resonant panels are TUNED treatments and as such need to be placed in very specific locations within a room to work best; they also can make things WORSE if not correctly chosen for the job. This is why everyone, INCLUDING Ethan, now recommends broadband absorbers FIRST - it's much easier to get a smoother sounding room with less "rocket science" that way... Steve

knightfly wrote:

Resonant panels are TUNED treatments and as such need to be placed in very specific locations within a room to work best; they also can make things WORSE if not correctly chosen for the job. This is why everyone, INCLUDING Ethan, now recommends broadband absorbers FIRST - it's much easier to get a smoother sounding room with less "rocket science" that way... Steve

OK!!! I get it, that's why I asked before about how to tune a panel for specific freq. I understand that broadband is the way to go. How can I build a broadband absorber? it's a frame with thicker than 1" fiberglass #703 in it and covered with fabric, am I right? What abouth hangers? they are broadband too because all that fiberglass absorbs High frequencies too. Is it safe to put the hangers and wich sizes will be better for low to lo-mid conditioning? Thanks. Ed.

I guess everybody is very busy for taking the time to answer the specific questions I'm making. I have read as much I can in the other threads and surfed the web for learning, so I can avoid asking all the time, here in this forum, questions that have been already answered. But, since I'm in the process of contruction I need quick answers, most of the time to confirm or modify what I'm doing at the time I write this message. I want to thank Knightfly, I know he's a very busy guy. I will stay in tune and l'll take my decisions based on my small knowledge about acoustics and the theory I've found about. I regret not having in any of the threads I started a true dialog with a more experienced person who could help me and advise me in every step of the construction, I suppose this cost money and that's something I can barely afford to my studio construction purpose. I'll post some pix of the finished studio, I hope not to make many mistakes. Big thanks for those who took the time to answer. Ed.

Ed, you're right about the time and money thing; John, I, and Aaron are all spread pretty thin these days; I understand your frustrations, but at the same time before I can make recommendations I need you to respond to Dan's question in your other thread http://www.johnlsayers.com/phpBB2/viewtopic.php?p=38808 about the strength of your place, which floor you're on, etc - I have to say that I really admire what you're doing, by the way... Making portable treatments is fine, Kendale has done so in his thread and they work fine. Just make the backs as solid as you can (I'd use at least 19mm backs since the formulas assume RIGID backs for both slat absorbers AND resonant panel traps. Positioning of slat absorbers isn't quite as critical as for panel traps, since they seem to act both as a passive absorber and as a resonator to some extent. Panel traps, in order to do much at all, need to be at the high PRESSURE point for their specific tuned frequency - this can end up being a place where you can't allow them to be. There are two main ways to determine WHERE these need to gp; one is to walk around the walls with a microphone hooked to a RTA, and place the panel where it's design frequency peaks. For all but first harmonic modes (lowest frequency ones for each dimension), there will be more than one choice for this. Another way is to download the Harmon mode calculator from their site http://www.johnlsayers.com/phpBB2/viewtopic.php?t=5801 And only consider wall locations where the frequency you're trying to control has a PEAK in the display - if the Long wall of a room gives a mode frequency of 90 hZ, for example, and it's a SECOND harmonic, (12'6" length will do this), then there are three places where a 90 hZ resonant trap will work; at either end of the long wall, or at its Center. IF you use the calculator and set length to 12'6", you'll see what I mean - it's very visual, and the curves represent sound PRESSURE so where they are highest is where you'd put a panel trap. For absorbent traps, you do NOT want a solid back; just a perimeter frame and some corner braces with the rockwool inside the frame, cover with cloth and make some feet so it will stand up, and you're DONE. If you make these at least 4" thick (100mm) you can place them across corners, along walls, or several FEET away from a rear wall (in the CR, for example) and they will work. No airtight seals, just put them up and listen to the difference. Before I would build even ONE panel trap, I'd build at least EIGHT of these; 4 for the vertical corners, one overhead for a "cloud", two for sidewall reflections, and one for the rear of the room - with free-standing speakers, another one or two between the speakers and the wall you'd be looking at while mixing. There is a pictorial on another member's design of a "cloud" in the "stickies" section here - and a concept drawing of a free-standing version here http://www.johnlsayers.com/phpBB2/download.php?id=2884 I drew this using pipe for a stand; the connections are what we call "floor flanges" - or you can just extend the sides downward and fasten boards at right angles to them for feet. This would be for a portable side absorber, for corners you'd do it more like these http://www.johnlsayers.com/phpBB2/viewtopic.php?t=4581 Only it's better if they are wider (like 1 meter) for corner absorbers. Again, NO BACK other than necessary corner bracing. In all these units, stay as close to 3 PCF (48 kG/m^3) as you can find, and NO RIGID FOAM insulation; it's USELESS for acoustics, period. Hope this helps some; I still need your answers on the other thread linked at the top before we can help much... Steve