Home » Uncategorized » I’ve located a portable sound-proofing booth, and I need an audio engineer to comment

I’ve located a portable sound-proofing booth, and I need an audio engineer to comment

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I’ve identified a potential sound-proofing unit, with a base price of about $7400.00.


The booth reduces 125 Hz sound by 30 dB, which is rather good for such a small unit, but what I need to know now is, what exactly can be done increase the noise reduction? Foam panels? Rubberized mats? Putting the booth on stilts?

I need an experienced audio technician or audio engineer to help this move forward. Once I’m satisfied with these answers, then I will purchase the unit as soon as the funds become available.





  1. Mike says:

    Hey Glen,

    Couldn’t you just to one of those music studios and ask them if you could utilize one of their sound proof rooms?

    You could go near the studio before you speak with them and listen for the hum (you may also be able to use google maps to list recording studios in places where your huminfo map has reports of the hum occuring).

    If you do hear it, you could contact them & explain the situation (and that you don’t actually need to record a demo, you just need to be escorted into and out of a sound proofed booth for a few moments).

    Tell them about how you’re trying to figure out how to stop the pain from the hum, give them links/information so they can understand that you’re not just trying to prank them, etc.

    I’d recommend you do this via e-mail if possible (maybe start with a phone call if you can’t find an e-mail or if you get no replies) so you can fully state your case and present them with evidence – it’s hard to do something like that over the phone.

    Maybe if/when business is slow for them they’ll humor you, or maybe you could just pay $100 to spend a few minutes in one of those booths.

    I’m sure there’s got to be some music/sound studio out there that doesn’t always have someone using those booths.

    Now…finding a studio exactly where you’ll also be hearing the hum may be an additional challenge; however based on how widespread it may be possible.

    That way you can at least establish if soundproofing is a viable option before you spend lots of money.

    Oh and I’m sorry I don’t have enough time to read all of your blogposts, but I did find the ones on VLF & Demming boxes. Perhaps a more economical “2nd box” could simply be a steel helmet? You mentioned that “1.2 mm layer of mild steel should do the job” in one post.

    If you can at least lower the intensity while standing inside of a soundproofed booth in a music studio while wearing a steel helmet, that may validate your hypothesis a bit more so that you can be sure you won’t be spending money on things that won’t work.

    Never the less, if you’re looking to enhance the soundproofing capabilities of a soundproof booth, just look at how they do it in the music industry.

    According to http://www.sonicscoop.com/2012/11/29/soundproofing-the-small-studio/ only mass and trapped air can do the trick, and those are only obtained through solid construction.

    This is part of the reason why I recommend appealing to a big recording studio if you hear the hum near the studio – they already have the infrastructure there.

    I believe this is the last posting I’ll make.

    I hope I haven’t been too much of an annoyance and wish you the best of luck.

    • This all sounds good, but the “helmet” concept will not suffice, because that will simply not block VLF from entering the body. As for using a professional music studio, that’s an interesting idea, and might be useful as a pilot investigation, but won’t suffice for anything approaching a blinded controlled study. Because the booth is portable, it and its VLF-blocking counterpart can be transported to different Hum locations.

  2. Gridlocked says:

    If any vibes/hum sufferers are anywhere near Hendersenville, TN (Nashville area), you can take a free tour of the Trinity Music City (TMC) recording studio. If more time is needed, they rent recording rooms beginning at $40/hour, not bad.

    If you wanted to explain the hum (& LF vibes) of many sufferers, they should be more compassionate than the “average bear” as TMC is a Christian entity. They’d probably even offer to pray for all of us! (I realize not every vibe/hum sufferer would appreciate that gesture, but I would!) Here’s their site link, the contact lady’s name is Bonnie: http://tmcrecordingstudio.com

    • Yes, but I urge caution with this. We all know that sufficient levels of ambient noise can mask the Hum. A person would need to establish that s/he can hear the Hum within that building before stepping into the studio. With all the surrounding hustle and bustle that goes on in most buildings during the day, this might be quite a problem.

  3. Gridlocked says:

    True. Hopefully, anyone who might come close to visiting any recording studio for hum purposes would be aware of the steps to take before, during, after such a visit, & take good detailed notes. Maybe a “late night tour” could be arranged (less background noise). 🙂


    Question re blocking ELF in Deming Box:

    Since all Sound is Vibration/Frequency & all Vibration/Frequency is Sound, does it matter if it is caused by Ionosphere, Power Grid, Military, Machinery, etc., as far as soundproofing/vibration-proofing the Deming Box? Is Machinery LF different than EMF-LF (as far as solutions go, that is).

    In other words, would the same industrial anti-LF-vibration solutions work for the Deming Box?

    I may have posted here last Fall or so that I originally thought Vibes/Hum were due to ground/dredging or machinery, so spent the first 1.5-months at anti-vibration forums/blogs, building construction websites, etc. I collected a lot of comments/suggestions from the web & may have posted 1-or-2 previously, such as that “Sorbothane” product used by NASA & NASCAR.

    If Deming Box could be guaranteed not to vibrate, then maybe that would also guarantee ELFs would not be heard(?) I’m just guessing, I have no idea. But here’s 1-product I had read about that specifically mentioned LFs. Maybe prop Deming Box on coils to stop vibes = sound(?):

    Spring Isolators – supposedly work better than rubber mats for LOW FREQUENCY vibrations:
    “IMF Simple Spring Mounts – Unhoused”:

    And speaking of recording studios, I’ll include this one as well, though they did not mention LFs specifically:

    “What you want is these neoprene rubber sound isolation pucks. You don’t need a full layer under your plywood, just enough to support it, so maybe a grid every 18 inches. Or get the pad shown at the same link. Not cheap, but very effective. This material is used in industrial situations to isolate equipment from building structures and works better than anything else you’re going to find:
    Those rubber isolation pucks work great, that is what they use in a lot of recording studios to keep sound from transferring through the floors from one room to another. The thing about them, though, is that you have to use the right amount for the weight they will be supporting. To reduce the sound levels transferring to your floor, you want your material to act like a shock absorber. If it is under too much load, it won’t work (imagine standing on a tiny spring, it will squish down all the way and not be springy any more). Alternatively, if it is not under enough load, it also will not work correctly (imagine you have a spring designed to hold up a car, and you are tapping in it lightly with a hammer. The spring won’t be squishing down at all because there isn’t enough force, so it will be acting like a rigid object and transferring the hammer blows to the surface below). So, if you do decide to go the rubber puck route, make sure you talk to the person selling them to you and find out what their optimal operation load is, and buy accordingly.

    Hardcore bass (LF?) music/automobile nerds use Anti-Sound Anti-Vibe mats called “Dynamat,” “FatMat,” & “RaamMat,” all of which include aluminum in them (good for RF but maybe not ELF!)

    • Just to zero in on one point: my suspicion is that VLF radio energy can be interpreted by the central nervous system as sound. The experiment aims to sort out whether the Hum is indeed a sound in the usual sense of the word, or the type of bodily interpretation I mention above.

      • citrique says:

        I don’t understand where is involved an anti-VLF booth for this experiment. The only way to prove that it is bodily interpreted would be to do a test with someone whose ears do not work “mechanically” and see if he can feel something in presence of the hum, “heard” by someone else…. Did I missed something ? I mean every vibration is a sound, so if you cut all vibrations in a booth, there is no experiment to do.

        In what I feel concerning the hum, I see it like an unusual sound (because of its power mainly) and so our ears are triggered by unusual ways (by bones vibrating around ears or by the skull itself ?), but still I feel that the ear drum is in action.

      • jimvandamme says:

        I’m still trying to understand how this is going to determine definitively what causes the Hum. Why not spend all this money – actually a smaller amount – on VLF analysis hardware and try to correlate that with Hum? As Deming pointed out, there was no correlation between detectable LF acoustic emission and Hum. He proposed 3 boxes: a control, a concrete “soundproof” one, and an EM shield. Why not do the EM shield first?

      • I am. Today I found a local source for 4ft x 10 ft mild steel (0.050 thousandth, which is even a bit thicker than 12 skin-depths for a 10 kHz radio wave wave). Each sheet is about $90.00, and I think I can do a decent box with two or three sheets. The welding shouldn’t be a big deal, but the door/hatch is a concern. I’m not sure yet how to handle that. I’ve Googled endlessly on advice for welding VLF-proof containers but all I ever get either my own blog entries, or links to people selling mu-metal. Any thoughts?

      • citrique says:

        Door should not be a big deal, in the worst case, put a wood frame around the hole outside with metal screws from inside, make a door a litlle lager than the hole with a thin wood sheet in / steel sheet out, from inside you can set some hinges across the steel screwed in the wood frame. You’ll need some spacers of course, then with appropriate fasteners (like those we often see on tool boxes…) fixed around the frame from inside you should get enough pressure to maintain a solid contact between the door steel and the wall steel. This is a basic idea but talk with some builders and I’m sure they will easily find some smarter solutions.

        But… +1 to invest first in some VLF analysis hardware + travels. First thing, before doing experiments, would be to get a real idea of what is (or are) the hum. I’m even not sure that we all hearing the same kind of hum.

        Like I previously said, I now suspects that the wind turbine parks create this hum beacause in my case some facts are matching. Those giants creates VLF, this is known, and VLF are travelling long distance, this is also known. I heard the hum at more or less 80 km from the park (the farest place I went since I hear it), so let say that the hum can be heard in a 200 km circle for 1 park, it means that 25 parks could cover from Vancouver to Montréal…, 5500 km, and so, almost the whole canadian population.

        This is an example of course, but if we can get a hum map based on analysis, we could cross it with a map of other potential sources like wi-max or cell towers etc etc… and if it’s not matching, then we can imagine that it is a more global issue.

  4. citrique says:

    Hi. Sorry for my english… I’ll try to be clear but please be kind ! I worked in studios and saw some of the install of a double booth in a 100% concrete building. Have to say that the booth quality seems to be higher that the one you plan to buy. There were no springs to insulate from the floor but the principle was to get rooms into a room, with an air trap around the booth. The result was good for musical purposes of course, but the low frequencies were still passing in the building when the speakers volume was “moderately high”. This to say that you can forget about foam panels or rubberized mats, this will be a total loss of money and effort. The best option to tame VLF are springs, but for what I heard about, it needs to be installed in a concrete floor and in a large number, still in the concept of a room in a room… So, knowing a little about soundproof booth after I worked in, I doubt that it will be enough to stop the VLF I hear, they are not so different than a well insulated house, like mine, and I hear the hum more from inside than outside because outside noises are blocked, but not the hum VLF… I don’t want to be too much affirmative but I’m really septic about a soundproof booth against the hum, you may obtain the opposit result ! Otherwise, in my concern I supect a wind turbines park located at 50 km from my house to generate this VLF I hear, they started to run this project in the same period I began to hear the hum (sept 2013) and the rare days I don’t hear it seems to match the days they are doing maintenance or stop the turbines because of weather matters, from what I know. Did you searched about wind turbines ?

  5. Lisle Daverin Blyth says:

    Hi, Thanks Glen. I have contributed $100. Please remember the rand (our local currency) is taking a drubbing; one of the worst performing currencies in the world. There’s every indication the Deming box experiment is our way forward. Hum sufferers should be first and centre in this research. If we show willing – put money where our mouths are – it strengthens our position. An effort on our part to do the suggested experiments will press home the point. The hum is real, it has robbed many of us of our former lives. After two and a half years of the ‘hum’ mine is a shadow. And as for the medical doubters who say it’s a bad case of tinnitus…. there are no decent words. I’ve had tinnitus for most of my life and the hum is NOTHING like it. Even Deming’s paper says it’s not the case. I equate it to having a raging, debilitating condition and so-called health professionals pat you on the head and suggest a nap. More thoughts: It’s not what I want from life; it’s what life wants from me (Victor Frankl).It has been my life experience that once one shows willing and takes action, all forces, invisible and seen, step in to help if the cause is right and just. Yesterday I walked past two fund raising tables en route to a grocer. One was Doctors without Borders (MSF) and the other was on behalf of the National Sea Rescue Institute (NSRI), both were raising funds for their respective humanitarian organisations. It sets an example for us in terms of helping ourselves help others. Take good care of yourselves, Lisle PS Spell check’s dropped off the twig so please overlook any bloopers. Date: Fri, 27 Mar 2015 20:10:09 +0000 To: pangaban@hotmail.com

  6. citrique says:

    The more I think about your project of buying a soundproof portable booth and the more I think it is useless… To be more precise I will give some facts I experienced in case of you are not aware of what you can really expect from a booth. From outside a booth, we can hear a piano playing inside the booth, really damped, but we can hear it clearly. Also, as I told in my previous comment, the studio I worked in had 2 booth (one for the control room, the other for the takes), they were distant by more or less 10 inches. All doors closed and mics down, I was able to hear a male singer singing not so loud, no need to say I was in the control room and he was in the other booth… So really, make some tests before spending money in a booth, you may be very disappointed. And I only speak about “normal frequencies”, under 100 hz, the challenge is multiply by ? !!!

    Also, I think that the VLF of the hum (the one I hear…) is different from other LF sources because it is conducted by the air and not by the ground like industrial engines or other noise sources. That’s why even sophisticated systems using springs will not work because the vibration hits the walls. I can compare my house to a soundproof booth, when my wife is playing the piano I can hear it the same way I was able to hear the piano from a booth, and like I said before, the hum I hear is present at the same level inside or outside the house, if there is wind outside it is difficult to hear the hum from outside because the wind is masking it, but once inside the house I no more hear the wind but I hear the hum…

    I still work around sound and wanted to build my little studio outside my house, I’m now hesitating to spend money in this project because I know I will hear the hum even with double walls etc… I’m more and more thinking about selling the house and moving away, sadly because I have everything I can dream of in this place…

  7. Tobypaws2002@aol.com says:

    Dear Glen, Thanks for your interesting news about a sound proof room…. I have seen something similar, recommended to keep sound IN ! As in music practice…. When I was suffering greatly from LFN, I think due to the prescription drugs I was having (Diazepam, Lorazepam, Temazepam : Benzo-diazepines), I triedlining a small bedroom with roofing felt (strong, rubberised material) , then a polystyrene layer, then I think, wallpaper to improve its appearance…it was a long time ago, but I remember , while it did cut down outside noises a little, e.g., cars, motor-mowers, motor bikes, it did not block The Hum’. This I think was because I could not line the room completely, to include ceiling and floor. We did have double glazing, but as I always point out, that reduces outside general noise, but LFN sails stright in, due to its long wavelength. So this is what you’re up again with low frequency noise. I went into the anechoic chamber at Southampton University, courtesy of Dr. Flindell and 2 students. The chamber was made of brick, with a lining of foam ‘cones’, that made the acoustic quite ‘dead’. BUT I noticed that LFN was still getting in. And it showed on the computer graph / monitor present inside the chamber.I think the frequency was in the low 30’s Hz. Very faint, (the students could not hear it, but I could, because of my super-sensitive hearing at the time). I later tried listening in a much smaller sound proofed chamber (claustrophobic,like a small cupboard : I was glad to get out ), and there was not as much LFN in there, suggesting that my ears were not what was causing the impression of LFN. Plus, at the same time I was able to find several places that were silent, which showed to me that what I was picking up was an external noise, not tinnitus. So the point is, as I think I say in my long document , the ‘Information Pack’, to be found now at _www.healthwatchgloucestershire.co.uk_ (http://www.healthwatchgloucestershire.co.uk) that it is notoriously difficult to block LFN. The ‘room’ you mention seems very expensive? Could someone build a multi-layered ‘room, isolated from the ground / floor? Suggest different densities of materials, e.g., foam, cement, roofing felt / rubber/ slate, etc., because every time a noise has to get through a different layer, it loses some of its energy……. Also as I say in the Info-Pack’, air would have to be ducted in, because the smallest hgap could let airborne noise in…. Sorry to ‘go on’, but there is another important point, if you made a sound-proofed room as suggested above, then a person’s ears might try to hear ‘ more, i.e., if the brain thinks deafness has set in, because it can’t detect ordinary sounds, then it will ‘turn the volume up’, and then probably notice any remaining LFN all the more….so it’s a big puzzle.

  8. Tobypaws2002@aol.com says:

    Dear Glen, This is my second e-mail to you today : I’m sorry, I clicked on “Send Now”, instead of “Send Later”. I wanted to make sure that the long document I sent to _www.healthwatchgloucestershire.co.uk_ (http://www.healthwatchgloucestershire.co.uk) . was still stored there. There was a problem recently when it was omitted, during re-organisation, and the incoming phone calls from sufferers increased dramatically , again. I contacted them, and they kindly reinstated the document, which is now available as a download, http://findaservice.healthwatchgloucester.co.uk/view/low-frequency-noise-suf ferers-help/3198 I have just checked it, and it is there O.K. It is not written in ‘scientific’ language, merely in my own ordinary style, but I hope that means it will be easier for ‘ordinary folk’ to follow….. Did you say you had stored it also? It would be great if you could list it somewhere, as you are more of an established scientist than I am ….. Perhaps Humforum’ might take it, so that people can read it for themselves…. If time permits, I would greatly appreciate it if you could write back saying if you have the document, or perhaps download the version now available at the Gloucester service….. I hope my comments about trying to block LFN may have been of some help. Geoff Leventhall has written extensively about LFN, and he might be able to assess it….you might like to mention that I suggested you contact him… _geoff@activenoise_ (mailto:geoff@activenoise) Yours Sincerely, Rosemarie Mann LFNS Help, England. ========================================================================

  9. Andy F says:

    Retired audio engineer: the rubber pucks are correct – the TV news studio I worked in had a concrete slab floor mounted on rubber pucks to eliminate vibration from the ground and floors below. You should be able to feel a slight bounce if a heavy person walks across the floor. (One puck actually sagged over time and the cameras would sometimes wheel themselves across the floor with the resulting slope!) The basic principle to build a room within a room with heavy material is correct. Foam panels inside don’t provide soundproofing as such, just reduce echo from sound sources within the room (sometimes known as a ‘dead’ room).

    • Exactly the type of response I needed. But my question is, what can we accomplish with, say, $15, 000.00? I.e., what is the best portable 100 Hz reduction we can expect for that kind of money? Cheers, Glen.

  10. jimvandamme says:

    You’re going to need some means of sensing and measuring both EM and acoustic energy. Shielding is secondary; you don’t need to achieve high levels of it. You just need to be able to measure it adequately and be able to correlate it with levels of hum. Attenuating it highly would be appealing to a hearer, but that’s not the purpose of your experiment: it’s to determine the cause.

    I worked for 39 years at the Air Force Research Lab and might be able to tap their resources. They have anechoic chambers; I owned one at one time, and I built a low-performance one. They’re RF sealed, but acoustically quiet….REAL quiet. They may still have screen rooms somewhere. They have lots of RF equipment, but not so much acoustic. Possibly I could get an Emeritus position (unpaid) for a well-defined set of experiments, and use their equipment and extensive library. Just a thought.

    Interestingly, there’s no hum hearers within 50 miles of the lab here, despite all the technology (and windmills).

    Oh, I also know a bunch of Deaf people. If I radiate them with a VLF signal, can they hear it?

    • Actually I don’t need to measure it at first if VLF radio is the culprit. If the mild-steel enclosure blocks the Hum, then the answer is provided. No doubt that measurements of different types would follow and would be useful (On a side note, I’m still not sure what the implications are for measurement if the Hum is caused by a standing VLF wave or an interference pattern). It would be excellent if you could do Emeritus work in this area and get access to the equipment. Please keep us updated on this.

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