Very small iso booth solution, reflexion filter?

Hi, I rent a space where the previous owner convinced the landlord to build a small iso booth (stretch of the word...). It's roughly 1.5 x 2 x 2 m. As expected it has lots of reflections issues and works at the moment pretty much like a resonance box. So far I have only used it to lay down guides and not been overly concerned as I mostly track elsewhere however for an upcoming project I'd like to be able to do lots more work at my place. What's the most practical thing to do here. There isn't much space to put traps and I'm not sure how far I'll get with putting acoustic foam all over, I reckon I'd still have low frequency issus, no? It's also a rented space so I can't (and don't want to) start messing with the frame construction or the floor. Is the easiest option just to get a se reflexion type filter? Cheers Johan

if you can get away with the reflexion device, why not?

Sorry, I strongly suggest that you treat your room. or use a gobo/reflexion filter in a treated room. Their marketing for this 'reflexion' filter is bullshit. (I honestly do not believe that these people even know anything about acoustics - only marketing...) You can not use something like that in an untreated room and get good recordings. This is due to the resonances in the room which the filter can not remove because the wave lengths are too long. The resonance you mentioned is the problem. ;) Cheers, John

OK, I guess I'm just showing my ignorance here, but what on earth is a "reflection filter"? Sounds like marketing hype to me... how can you "filter" reflections anyway? Does someone have a link to such a device? - Stuart -

JHB - i think he's referring to the isolation booth issues - we don't really know anything about the room outside it... but agreed, for the reflexion to have any chance to work the room is used in has to be acoustically viable for the most part. Stuart - http://www.seelectronics.com/rf.html

Soundman2020 wrote:

OK, I guess I'm just showing my ignorance here, but what on earth is a "reflection filter"? Sounds like marketing hype to me... how can you "filter" reflections anyway?

Glenn gave the link. In acoustic terms it is a small absobently treated semicylindrical device effective down to about 1 kHz due to its size, that is put in the middle of the area of lowest sensitivity of a cardiod microphone. Andre

Thanks for the link, Glenn. I'm seeing but not understanding: curved perf panel with foil, foam and an air gap inside? All contained in a thin little thing like that? How on earth is it supposed to work? :!: The perf panel itself looks to be something like 80% :shock: , and I'm more than a little perplexed by the statement: "The sound waves then hit a layer of Aluminium foil which helps dissipate energy and break up the lower frequency wave-forms,"... Maybe it's just me, but I'm having a rather hard time figuring out how aluminium foil is going to "break up" low frequencies... Unless somebody change the laws of physics last night, low frequencies wont even SEE a thin sheet of aluminium foil that is maybe a couple of square feet, maximum! Then curiously they show a graph and a photo of the device being tested in an anechoic chamber, where the two lines on the graph ("with" and "without" the device in the room) are almost identically superimposed on each other, and somehow this "proves" that the device is working? The say that this shows the thing does not "color" the sound, but to my point of view, it appears to be showing that it does nothing at all! Plus, since this thing is billed as a "reflection" filter, it seems rather pointless to test it in a room which, by design, has NO REFLECTIONS AT ALL! That kind of is the purpose of an anechoic chamber, last time I checked: a room with no reflections. Why would you test a device that kills reflections in a room where there aren't any reflections that can be killed??? That would be like testing a fantastic new waterproofing product in the middle of the Atacama desert, and then when the product doesn't get wet claiming that it works really well.... :) How come they didn't test it in a reverb chamber? I wonder why.... Can you say "hype"!? If that thing works at all, it is just the little remaining metal plus the foil reflecting some of the highs, and the foam absorbing a fraction more. It might well do something for the highs, but I simply cannot see it doing a damn thing to the lows, which as we all know is where the REAL problems are in most rooms. So the only conclusion that you can come to from perusing the add, is that if you happen to have an anechoic chamber on hand, then it is the perfect device for you, since it won't change anything at all! :shock: I sure can see why every studio needs one! :) - Stuart -

i think the idea is to put a bit of isolation (think Micro Gobo™ 8) ) around a mic to cull off any extraneous reflections. does it work? maybe. GIK Acoustics and Real Traps have their variations on the theme and i'm sure there are others. http://www.gikacoustics.com/gik_screen_panel.html http://www.realtraps.com/p_pvb.htm i just use a simple frame and packing blankets or other heavy textile when needed. http://sketchup.google.com/3dwarehouse/ ... =0&safe=on the point of my original response was to query the OP on what was its use in the room outside the isolation booth... Eric Desart had some interesting info on thin foils and thin sheets used for absorption and the range was fairly wide if memory serves me correctly.

Thanks guys for your replies. I've posted this on Gearslutz also and John was kind enough to reply on there too. http://www.gearslutz.com/board/studio-building-acoustics/543281-very-small-iso-booth-solution-reflexion-filter.html The iso booth is a simple wooden frame in the corner of the room, it's a good construction but it's done with little or no thought to actual isolation, it's purely cosmetic. The rest of the room is around 4 x 5 x 2.20. There are suspended tiles in the ceiling. The studio is essentially a programming room and the sound is good enough for simple mixing and editing. I usually do my tracking and mixing elsewhere so up til now the sound treatment hasn't been that much of a concern. However for an upcoming project I'd like to be able to lots more tracking in my place. Although I know that the iso booth is not ideal it does provide a "recording studio" look to the place. This might sound silly but it's psychologically sometimes an important factor and for this client it will be. For this reason I'd like to be able to use the iso booth rather then the room outside. It would probably be wise to improve the treatment in the main room but because of time issues I don't think I'll have time to do that properly. The studio is also rented and as I'm on the lookout for a place with a proper live room I'm reluctant to spend too much time and money on this place. John suggested putting trapping in the ceiling of the iso booth. Could I just put rockwool on top of the suspended tiles above the iso booth? The back of the booth have shelving so with the door there is only one corner to put a trap - you reckon it's a good thing to trap it from floor to ceiling? Cheers Johan

Johane wrote:

... putting trapping in the ceiling of the iso booth. Could I just put rockwool on top of the suspended tiles above the iso booth? The back of the booth have shelving so with the door there is only one corner to put a trap - you reckon it's a good thing to trap it from floor to ceiling?

Johan, Rock wool above the tiles will do excellent at trapping bass. and floor to ceiling is best. - Are the shelving units full? Maybe you could use empty spaces for absorbent covered with fabric...? - John

AVare wrote:

... In acoustic terms it is a small absobently treated semicylindrical device effective down to about 1 kHz due to its size, that is put in the middle of the area of lowest sensitivity of a cardiod microphone.

+1 Amazing thing, isn't it? (ok, I'm being sarcastic) - So, It's just a cute looking gobo on a stick. and it's not very effective because it's behind the mic and not behind the performer... - John

jhbrandt wrote:

So, It's just a cute looking gobo on a stick. and it's not very effective because it's behind the mic and not behind the performer...

What amazes me is that it has ANY effectiveness. :? Andre

It does read "dry" vocal, and I can see how that design could take all the reflections that came off the wall in front of the performer away, taking the room out, if you will. And possibly add some gain to the mic/voice since now less is actually escaping due to the partial enclosure. I'm just glad that Stevie finally got what he has been waiting for :)

xSpace wrote:

I can see how that design could take all the reflections that came off the wall in front of the performer away, taking the room out, if you will.

Above 1 kHz. I will add crispness, and keep the low (if you can think of below 1kHz as low) end the same. Can you say 40's studio sound? Andre

jhbrandt wrote:

Johane wrote:

... putting trapping in the ceiling of the iso booth. Could I just put rockwool on top of the suspended tiles above the iso booth? The back of the booth have shelving so with the door there is only one corner to put a trap - you reckon it's a good thing to trap it from floor to ceiling?

Johan, Rock wool above the tiles will do excellent at trapping bass. and floor to ceiling is best. - Are the shelving units full? Maybe you could use empty spaces for absorbent covered with fabric...? - John

Thanks John for some excellent advise. The shelfs are used as a storage unit so we could definitely put that stuff elsewhere and build some traps instead. Johan

Above 1 kHz. I will add crispness, and keep the low (if you can think of below 1kHz as low) end the same. Can you say 40's studio sound?

I found some audio samples on-line done using this gadget: they sure don't match the graph! And they sure do match "40's studio sound". But I'm not sure that I'd call that "crisp". Maybe "tinny" would be closer to the truth. I'm thinking that a garbage can lid with a thin blanket draped over it would produce something similar.... :) - Stuart -

Stuart, You got that right... like I said, -- I don't think the ppl that make those things are designers or engineers - just clever marketers. ..And I actually have a 'VooDoo' page on my site where I list bullshitters. hehehe. -- John

Looking over your "VooDoo" list, John, and glad to see you have some of my favorites on there! Gotta love the US$ 1,500 power cord! I always wondered how making the last couple of feet from exotic materials could compensate for the hundreds of MILES of cable on the other side of the wall, that goes all the way back to the power station... :) I reckon you could grow that list rather long without too much trouble, and I reckon the device listed above is a sure candidate! Just to make things clear here: I'm NOT knocking Ethan's portable device, since Ethan does not make any outrageous claims about it. He simply tells you what it is designed for, and how it works. I have no doubt that it works substantially as advertised. But the claims made for this filter thing are just off the chart, and "acoustically improbable", to put it politely. There's a big difference between what Ethan makes and says about it, as compared to what some other folks make and say about their gadgets. - Stuart -

Thanks Stuart. If you have any VooDoo sites that I could post.. please send me the list to check out. - You and I both see way too many innocent (well, maybe not so innocent.. haha) musicians and music lovers being taken to the cleaners. - Yeah, I'll have to give that reflexion site another look. It really should be on my list. Cheers, John

Here's a couple for starters, John: http://www.googobits.com/articles/1355- ... -free.html http://www.ehow.com/how_6633801_diy_-ch ... ofing.html http://www.ehow.com/how_6655753_soundpr ... cheap.html http://www.audimutesoundproofing.com/ba ... ctice.aspx Got more links stored somewhere, but in a hurry right now. I'm sure you'll LOVE some of the above! :) Truly excellent products! And they must be VERY effective, becuase I found them all on the internet... :lol: :shock: :roll: :!: - Stuart -

Thanks Stuart. There is a whole world of intuitive acoustics that I have forgotten! :? Andre

Thanks Andre! And I nearly forgot one of YOUR personal favorites: http://www.foambymail.com/soundproofing.html :shot: I KNOW how much you love that stuff! :) - Stuart -