Bunno77 Posted April 26, 2020 Share Posted April 26, 2020 This has been a great read Did any of this get off the ground? Were good codes found/written? Is the bloke in Singapore still operating? Link to comment Share on other sites More sharing options...
almikel Posted April 26, 2020 Author Share Posted April 26, 2020 nothing got off the ground Chris @hochopeper wrote the code to generate the sequence for 2D BAD panels Mike 2 Link to comment Share on other sites More sharing options...
Bunno77 Posted April 26, 2020 Share Posted April 26, 2020 Just now, almikel said: nothing got off the ground Chris @hochopeper wrote the code to generate the sequence for 2D BAD panels Mike A friend of mine owns a workshop with a plasma cutter so metal ones might be possible. If there is a bit of interest and the code to make them I can try organise something? Link to comment Share on other sites More sharing options...
almikel Posted April 26, 2020 Author Share Posted April 26, 2020 I'd be interested - @hochopeper - Hi Chris any interest from you? Link to comment Share on other sites More sharing options...
hochopeper Posted April 26, 2020 Share Posted April 26, 2020 (edited) 4 hours ago, almikel said: I'd be interested - @hochopeper - Hi Chris any interest from you? Yeah no interest from me at the moment. I think I need to buy a usb caddy for the old nvme drive that code was sitting on - I was planning on doing that soon. Unless maybe it is sitting in an old email to @almikel or @acg maybe? If you guys proceed then I should be able to dig the code out I guess. I'm a bit hesitant handing the code out to folks I don't know (there have been a few PMs over time) because I'd rather support DIYers than provide that work to someone starting a business - I'm not that smart and it took me a couple of evenings and a copy of the right book and a few cans of beer. I have no idea what info a plasma cutter takes as an input .... my code was calculating the hole centres on a sheet. That would be enough for someone suitably motivated to use some cad software and probably scriptable to lay out in the right cad software and export whatever it is that's needed by the plasma cutter. Edited April 26, 2020 by hochopeper 1 Link to comment Share on other sites More sharing options...
Bunno77 Posted April 26, 2020 Share Posted April 26, 2020 44 minutes ago, hochopeper said: Yeah no interest from me at the moment. I think I need to buy a usb caddy for the old nvme drive that code was sitting on - I was planning on doing that soon. Unless maybe it is sitting in an old email to @almikel or @acg maybe? If you guys proceed then I should be able to dig the code out I guess. I'm a bit hesitant handing the code out to folks I don't know (there have been a few PMs over time) because I'd rather support DIYers than provide that work to someone starting a business - I'm not that smart and it took me a couple of evenings and a copy of the right book and a few cans of beer. I have no idea what info a plasma cutter takes as an input .... my code was calculating the hole centres on a sheet. That would be enough for someone suitably motivated to use some cad software and probably scriptable to lay out in the right cad software and export whatever it is that's needed by the plasma cutter. Thanks for the reply. Sounds like a bit of trouble to find it. I know it isn't worth much via text but that isn't the intention at all for it to make money. I am interested in them for myself and thought it may help others here too around Brisbane. Definitely wouldn't be starting a business, he is flat out doing fabrication for farms, machinery and building trailers. I don't even know how long it would take before he could get to it as it may take months. I have some DIY absorption panels and spare Polymax that these could be glued to. Also doing a First Watt build soon It would be good to meet some more people from here that are in the Brisbane area when the madness is over. Anyways I did a bit of searching this afternoon and found the patents online but no real files that could be used for manufacture and I am very PC illiterate. I am not even sure if the thickness of metal would be suitable? The thicker ply or MDF seems like a better solution to me....??? 1 Link to comment Share on other sites More sharing options...
almikel Posted April 26, 2020 Author Share Posted April 26, 2020 Hi Dan, just build a 1D using timber slats - no code required, just a random sequence Mike Link to comment Share on other sites More sharing options...
HdB Posted May 10, 2020 Share Posted May 10, 2020 Hi Dan, Just noticed this thread - Is it possible for your mate with the plasma cutter to either be able to change out that cutter for a sand/water jet cutter (doubtful) or know someone 'in the business' who does have a 'water jet cutter'? They preceded the laser cutters, I think. Maybe, this might be an economical way to cut the 'holey baffle' plates. I don't think any of those old multiple head miller/cutter machines would still be around - they were old when I saw them some years ago - maybe in an old marine workshop Link to comment Share on other sites More sharing options...
hochopeper Posted May 10, 2020 Share Posted May 10, 2020 (edited) On 26/04/2020 at 10:01 PM, Bunno77 said: Thanks for the reply. Sounds like a bit of trouble to find it. I know it isn't worth much via text but that isn't the intention at all for it to make money. I am interested in them for myself and thought it may help others here too around Brisbane. Definitely wouldn't be starting a business, he is flat out doing fabrication for farms, machinery and building trailers. I don't even know how long it would take before he could get to it as it may take months. I have some DIY absorption panels and spare Polymax that these could be glued to. Also doing a First Watt build soon It would be good to meet some more people from here that are in the Brisbane area when the madness is over. Anyways I did a bit of searching this afternoon and found the patents online but no real files that could be used for manufacture and I am very PC illiterate. I am not even sure if the thickness of metal would be suitable? The thicker ply or MDF seems like a better solution to me....??? Dan and @almikel I got that external drive caddy and found the files - should be easy enough to run again. Need to know size of panels and also some specifics about what info is needed to operate the plasma cutter. At the moment it can spit out a list of hole centres. The other area of tweaking is in the hole diameter vs hole spacing (effectively the ratio of reflective surface vs open). I'd love to hear more about the First Watt amps you're building too - I'm hoping to fire up a few electronics projects that have been on the back burner - hopefully have some actual progress to show on them in the coming months Chris Edited May 10, 2020 by hochopeper 1 Link to comment Share on other sites More sharing options...
Ninooe Posted September 20, 2020 Share Posted September 20, 2020 I'm keen to try make a few of these panels, what material should I be using for the 2d bad panels? Link to comment Share on other sites More sharing options...
almikel Posted September 21, 2020 Author Share Posted September 21, 2020 thin steel, thin aluminium, thin ply would all work Link to comment Share on other sites More sharing options...
TRAUMFAENGER Posted October 9, 2020 Share Posted October 9, 2020 On 10/05/2020 at 12:21 PM, hochopeper said: Dan and @almikel I got that external drive caddy and found the files - should be easy enough to run again. Need to know size of panels and also some specifics about what info is needed to operate the plasma cutter. At the moment it can spit out a list of hole centres. The other area of tweaking is in the hole diameter vs hole spacing (effectively the ratio of reflective surface vs open). I'd love to hear more about the First Watt amps you're building too - I'm hoping to fire up a few electronics projects that have been on the back burner - hopefully have some actual progress to show on them in the coming months Chris did you write your code in python as well? how did you generate your MLS? scipy.signal.max_len_seq? i'm trying to find a way to generate different panels to avoid lobing, with my script i already get the famous RPG pattern with the right mls size 1 Link to comment Share on other sites More sharing options...
almikel Posted October 9, 2020 Author Share Posted October 9, 2020 9 minutes ago, TRAUMFAENGER said: i'm trying to find a way to generate different panels to avoid lobing Based on my understanding of diffusion generally, and more specifically with QRD panels rather than BAD panels, lobing is typically ameliorated by using an "inverse" panel mixed in with regular panels...I'm not sure how you would generate the sequence for an "inverse" 2D BAD panel...but turning an individual BAD panel 90 degrees in a series of "normal" panels would likely suffice...? Keep in mind the level of diffusion of a BAD panel is not the same as a QRD - I would expect less lobing from multiple BAD panels compared with multiple QRDs... Mike Link to comment Share on other sites More sharing options...
mpearce38 Posted October 9, 2020 Share Posted October 9, 2020 On 21/09/2020 at 10:53 PM, almikel said: thin steel, thin aluminium, thin ply would all work wanting build some VRP style bass traps like the one below thinking the outer skin would be perfect application for a bad panel if I was to use metal or aluminium who/ where could i have these cut???? Link to comment Share on other sites More sharing options...
almikel Posted October 11, 2020 Author Share Posted October 11, 2020 (edited) deleted Mike Edited October 11, 2020 by almikel misunderstanding Link to comment Share on other sites More sharing options...
almikel Posted October 11, 2020 Author Share Posted October 11, 2020 (edited) 13 minutes ago, almikel said: wanting build some .... bass traps like the one below deleted Edited October 11, 2020 by almikel misunderstanding Link to comment Share on other sites More sharing options...
almikel Posted October 11, 2020 Author Share Posted October 11, 2020 (edited) On 10/10/2020 at 9:12 AM, mpearce38 said: wanting build some VRP style bass traps like the one below thinking the outer skin would be perfect application for a bad panel if I was to use metal or aluminium who/ where could i have these cut???? @mpearce38 I've deleted my above responses - I didn't realise that was an RPG Modex panel There would be loads of tech gone into that panel - replicating its performance in DIY would not be easy given RPG licensed the VPR technology from Fraunhofer and added their own tech with a perforated front panel. Interestingly the perforations don't appear to be in a BAD sequence (which RPG invented), but the perforations aren't evenly distributed - RPG would have done this for a reason. Maybe they only wanted high frequency scattering as opposed to diffusion...maybe the VPR type plate resonances required won't work with a BAD style perforation pattern? Getting a metal plate perforated in a 2D BAD pattern by any manufacturer that does water jet cutting wouldn't be hard if you can provide them with the pattern in a standard industry format (AutCAD etc). Placing that 2D BAD pattern mask over absorption will get you a 2D BAD diffuser/absorber...I think RPG called them diffsorbers at some stage...but looking at their site they don't use that term anymore. The only thing the plate does is mask the absorption in a random way, so the sound impacting the panel is either absorbed (sound goes through a hole in the mask to be absorbed behind) or reflected by the mask (no hole) - which is where the name comes from - Binary Amplitude Diffuser (BAD). The Modex trap is an entirely different beast - where the steel plate is resonating and the material bonded to it absorbs the bass energy (which is the VPR part) - then RPG perforated it, allowing some energy straight through to the absorption - justifying their claim the Modex is a thin profile broadband bass trap. If you want to build/DIY VPR bass traps, I'd ask @acg to advise on where to purchase the same information he did. Making a 2D BAD mask to place over absorption will only have the bass response of the absorption behind, but with the significant benefit of reflecting treble back into the room with diffusion. cheers Mike Edited October 11, 2020 by almikel Link to comment Share on other sites More sharing options...
acg Posted October 11, 2020 Share Posted October 11, 2020 @almikelthe perforated front panel on the Modex plate is simply cosmetic, or diffusive, or both. The broadband Modex has the steel plate sandwiched in between two foam sheets and is thus inside the pictured unit. RPG have not added anything to the Fraunhofer patent. Because we are talking about bass frequencies anything we put in front of the VPR/CBA is unlikely to hinder the passage of the lows nor the effectiveness of the panel. One of the things that I had considered with my VPR's is a series of BAD panels screwed to the front of them (not touching the steel plate of course)...but BAD panels need distance for diffusion to be effective (circa 3m) and you cannot have a repeating pattern across a large area or they become problematic. If I were to do the entire 6m front wall in my room the pattern would need to be different all the way across or else they become a tone control. There is such a thing as a 3D BAD pattern patented by the Brisbane bloke, but they are not available unless it is a big consulting job...stereo listening rooms certainly do not fit that criteria. 1 Link to comment Share on other sites More sharing options...
almikel Posted October 11, 2020 Author Share Posted October 11, 2020 (edited) 1 hour ago, acg said: but BAD panels need distance for diffusion to be effective (circa 3m) and you cannot have a repeating pattern across a large area or they become problematic. Hi @acg BAD panels don't generate the same level of diffusion as say QRDs, hence they don't have as strict minimum listening distance restrictions as QRDs. I'm curious to where you sourced your circa 3m distance for BAD panels from?...I'm happy to use Cox and D'Antonio's rule of the minimum listening distance is > 3 x the lowest wavelength diffused, but I've never found stats/metrics on the interweb for how low BAD panels diffuse???... ...given you paid $ for the VPR tech, you may have done the same for BAD panels? I completely accept that repeating panels of the same pattern of diffusion causes lobing - with QRDs the standard practise would be to introduce an "inverse" panel in the sequence...I don't know how to create an inverse BAD panel...but turning a panel by 90 degrees would be a great start... ...or contact @hochopeper to generate a 2D BAD sequence across the entire area with no repeats... Chris wrote some code to generate a 2D BAD pattern in whatever size. cheers Mike Edited October 11, 2020 by almikel clarification Link to comment Share on other sites More sharing options...
hochopeper Posted October 11, 2020 Share Posted October 11, 2020 On 09/10/2020 at 9:30 PM, TRAUMFAENGER said: did you write your code in python as well? how did you generate your MLS? scipy.signal.max_len_seq? i'm trying to find a way to generate different panels to avoid lobing, with my script i already get the famous RPG pattern with the right mls size yep that's the one - the challenging parts were getting the co-prime dimension requirements etc 4 hours ago, almikel said: I completely accept that repeating panels of the same pattern of diffusion causes lobing - with QRDs the standard practise would be to introduce an "inverse" panel in the sequence...I don't know how to create an inverse BAD panel...but turning a panel by 90 degrees would be a great start... ...or contact @hochopeper to generate a 2D BAD sequence across the entire area with no repeats... Chris wrote some code to generate a 2D BAD pattern in whatever size. cheers Mike simply change an input argument ... my script at the moment assumes a single panel design so would be a little bit of rearranging to split it over a few sheets. Link to comment Share on other sites More sharing options...
Ninooe Posted November 11, 2020 Share Posted November 11, 2020 I'm in the process of giving this a go, not sure how they'll come out but if anything I'm wasting about $24 and time. I started by blowing up the 2d bad panel to 550mm X 550mm and sticking it on mdf, then drilled pilot holes before removing the paper and drilling the holes individually. I've got 3 peices of MDF clamped together because I cbf doing it 3 times. That's where I'm at now, if anyone has any suggestions I'm all for it. 3 Link to comment Share on other sites More sharing options...
almikel Posted November 14, 2020 Author Share Posted November 14, 2020 On 11/11/2020 at 9:06 PM, Ninooe said: I'm in the process of giving this a go, not sure how they'll come out but if anything I'm wasting about $24 and time. I started by blowing up the 2d bad panel to 550mm X 550mm and sticking it on mdf, then drilled pilot holes before removing the paper and drilling the holes individually. I've got 3 peices of MDF clamped together because I cbf doing it 3 times. That's where I'm at now, if anyone has any suggestions I'm all for it. wow - all by hand - props to you My only suggestion would have been if you want more panels, before you drill the big holes, use the top panel as a template to do some more... Mike Link to comment Share on other sites More sharing options...
Spike Posted July 12, 2022 Share Posted July 12, 2022 (edited) did anyone ever get these cncd? i'm also building a room & would love to do 1200 by 2400 over my bass traps with Martini CSR Im very keen & im also in Qld " in the city, Morningside ! happy to sling some one beer for the files & leads to get them cnc'd. Edited July 12, 2022 by Spike Link to comment Share on other sites More sharing options...
Silent Screamer Posted July 16, 2022 Share Posted July 16, 2022 On 12/07/2022 at 10:56 PM, Spike said: did anyone ever get these cncd? i'm also building a room & would love to do 1200 by 2400 over my bass traps with Martini CSR Im very keen & im also in Qld " in the city, Morningside ! happy to sling some one beer for the files & leads to get them cnc'd. I am attempting to understand the math (again) the cutting part I don't think would be too hard, but in order to generate the necessary G-Code I would want to write a program that automatically generates at least the basics of it automatically, dependent on entered dimensions. Something like.... Board width = x Board length = y Hole size = z Boarder A = a Boarder B = b Boarder C = c Boarder D = d Depth of board = e etc etc 1 Link to comment Share on other sites More sharing options...
Aido78 Posted July 18, 2022 Share Posted July 18, 2022 Great stuff…. I'm building some corner acoustic panels right now. I’ve gone the ultra cheap way using mdf and polyester insulation…..slots are cut with a laminate router… very jealous of those with access to cnc….. 5 Link to comment Share on other sites More sharing options...
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