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post #1 of 41 Old 07-31-2013, 10:49 PM - Thread Starter
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THE TEXT BETWEEN THE LINES IS THE SAME IN BOTH HERE AND THE DEDICATED ROOM BOARD - this is to explain the project, even though I expect each thread of discussion to be completely different. Here it's primarily for a discussion on the subwoofers, amps, electronic problems, there it will be for the room design.

After several recommendations of others, i'm finally moving the discussion over to... what I hope is the right board.


Original threads were http://www.avsforum.com/t/1477487/if-you-needed-4-hz-in-room-but-could-pick-the-room-how-would-you was the original topic, as well as posts on another board DIYaudio http://www.diyaudio.com/forums/subwoofers/232978-i-need-infrasound-seeking-advice-sub20hz-bass-budget.html (PS I still haven't caught up with every post in both places, i'm just starting this thread, so I can post a thread closer in each place directing future followups to here on AVSforum)

Unless you want to read everything there i'll bring anyone here up on the brief factoids:
- I'm aware infrasound may not be "audible", but it is perceivable
- I do not only want tactile bass transducers/bass shakers though I also plan to have that, the perception is interesting but not the same as infrasound waves
- I am not crazy, seeking self injury, colon rupture, cerebral hemmorage, or death of guests. Designing a system for too much doesn't prevent me from turning it down, most of this is about reserve capacity, dynamics, and extremely low response. My interest is more for DEEP bass than the loudest bass. (far more interested in 4hz reproduction at 130db than I am 160db at 45hz, even if a system may technically be capable of either) By deep bass I mean AC3 LFE .1 worship stuff, i've seen the waterfalls go down to 4hz on some movies. Some of those maybe were blind mastered (I don't know if anyone actually listened to them on a 4hz capable system) but since I want to do that myself, I want to be sure I can hear what i'm putting in.
- Yes i'm serious and this isn't a trolling post. Although i'm aware people elsewhere just can't control themselves, filling the thread with dozens of 'humorous' commentary doesn't really help the project. :-/ By what I can tell AVSforum may be the only place I can have this discussion with actual enthusiasm and sincerity so maybe that comment isn't even necessary... i'm just frustrated at how off topic some past conversations got..

Aka in brief yes i'm planning on building this and am seeking advice from others on how to do so rather than suggestions on why I should not or why they don't think I need to, even though it's probably 1-2 years off and early in the design phase. Which is good because it means the plans can still be totally changed without loss.


WHAT IS THIS?

I'm trying to create an all purpose audio mastering room capable of incredibly low "infrasonic" bass response on what's actually a fairly low budget relative to the performance. I'm an ambitious film student that wants to master LFE worshipping audio tracks not only for film, but possibly/ideally for Location Based Entertainment projects where the budgets or specifications can be even higher than what THX can reproduce for db limits or low frequency response. My first goal was to at least equal the performance of a Thigpen Rotary Subwoofer on alot less budget which apparently puts out 110db at 3hz. (and lower but not 'audible' below that) Other infinite baffle subwoofer projects seem to be able to reach 7-8hz routinely enough, so I was curious what would be involved in extending that response down even further. I picked 4hz just because it's one octave lower and i'm not sure how obtainable 2hz is. smile.gif

Because efficiency drops off so much at low frequency and because of budgetary limitations "billions of watts and square kilometers of cone area" is actually NOT the primary focus, but rather room design. From my understanding (which others have told me/I am totally new to this and don't even understand how this works yet) if you can create an effectively air-sealed, extremely solid room, the efficiency at low frequencies actually goes UP between the two closed off chambers. Scientific experiments seemed to show responses to sub 1hz levels anyways. However I probably don't want to sit in a solid concrete room just listening to infrasound all day, it has to reproduce all frequencies well, which is where the design challenges come in. I'm willing to compromise a few db here or there (on a system that by all accounts should already be able to play way too loud) for quality, but not give up the chart which shows room gain going up massively with each dropping octave into forever with a sealed room.


The biggest compromise i'm willing to make so far has been room size. One possibility was literally me sitting inside the speaker enclosure. Others had the suggestion that infinite baffle was the way to go. Because infinite baffle speakers are mounted between two rooms, I potentially can have it play bass into both rooms, so I proposed having a small (like minivan sized maybe?) back room as a single seat mastering room, with a 32" HDTV and some nearfield monitors, so that the bass level in that room would play as low and loud as possible. The same subwoofers would also be the home theater bass, just assumedly not as loud since it's a larger area, and inverted in phase for the signal obviously. It would be NICE if I could have the same monster bass to share with others, but it's most needed (at least at the beginning/I can always expand later) in just the mastering room, which can be the backroom of the IB subs for now.

The other design spec i'm willing to plan is having a room with effectively no air leakage to the outside world. Ignoring the needs of ventilation to like, not die from lack of oxygen (for which i've got several ideas to design around) it sounds like the tighter I can make the listening room, the more "room gain" I can rely upon keeping, similar to how car subwoofers seem to be capable of playing phenomenally low. (12hz with the sealed system in my car seemed audible anyways and that's merely a dual 12 inch) I don't know whether that has to be on both sides of the infinite baffle, or just the side you want the deepest bass in though.

I'm also aware that I will need a solidly engineered room because very low frequencies at 125db is normally house breaking bass, I don't need to be re-re-re-warned. smile.gif That's why the room will be a custom construction.

I'm hoping to use "poor boy bass traps" of lots of strawbale inside the constructed room (not a hard rule, just an expedient idea at hand/suggest alternatives) - I don't care if the room smells like straw, since the proposed home theater/mastering room will be built inside a barn anyways, they're pretty comparable to an STC of 55-60 by what i've heard. smile.gif However i'm wondering whether this will negatively impact infrasound efficiency all that much. The wavelength of infrasound is too long to be attenuated, but the room may not "appear" as solid to the speakers if there's lots of thick squishy acoustically absorbent material on every surface.

Room SHAPE can be anything - I was considering a room with nonparallel walls to eliminate most of the potential for room modes to begin with so I mostly have to dampen higher frequencies with room treatments. I'm not sure whether the infrasound cares what shape the room is though..?

I don't mind alot of speakers in the long run (8-20 subs in IB manifolds) but if possible i'd prefer to keep total sub wattage under 2kw because of wiring demands to the barn, but if I understand "room gain" properly this shouldn't even be a problem. I may wish to run stereo subs, or even three - stereo either IB or more conventional subs plus a separate IB LFE subwoofer channel with alot more cones. Lexicon's designer whose name I forget is a believer in stereo subs plus LFE for more immersion anyways and i'm hoping to eventually have an MC-12 in the signal chain.


I will add more information as I go (including some already in those threads i'm moving over from) but for now I just wanted to post this to see who else I can seriously discuss the project with.


That's the intro text (same as the room design board), but here i'm asking for insight and commentary into the speakers, amplifiers, electronics and similar side of the equation. Case in point - i'm told many normal electronics will not work well under 20hz, and perhaps not work at all at 5hz (or such was suggested as one of the hurdles the Thigpen sub had to overcome), and others had suggested using servo amplifiers for the LFE channel to get around it...

Also the decision for infinite baffle is still not set in stone, but i'm assuming that it will give me the best efficiency at 4-8hz or so. Horns I assume would be impossibly large, even tapped horns, and extended bass shelf sealed speakers are basically AFAIK just like a poorer version of an infinite baffle.
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post #2 of 41 Old 08-01-2013, 06:04 AM
 
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You're going to want basically the smallest room you can work with. Ideally you should just make a concrete box that is 100% sealed, and like 1 ft thick walls so they won't flex at all. Room gain will start at the 1/2 wave length of the longest dimension in your room, so the smaller the better. Gain is 12 dB/octave as you decrease in frequency, assume no air leakage or wall flexing. You want all your room dimensions to not be multiples of each other, to prevent standing waves. I'd just go with a bunch of sealed 18" subs, unless you can design the IB really well so there is no way for flexing of the walls, or air leakage. You need to check very carefully about the electronic components you buy. Lots of components roll off at 5-10 hz, so you have to find specific components designed for like 2-3 hz roll-off.
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post #3 of 41 Old 08-01-2013, 06:27 AM
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Originally Posted by JWagstaff View Post

You're going to want basically the smallest room you can work with. Ideally you should just make a concrete box that is 100% sealed, and like 1 ft thick walls so they won't flex at all. Room gain will start at the 1/2 wave length of the longest dimension in your room, so the smaller the better. Gain is 12 dB/octave as you decrease in frequency, assume no air leakage or wall flexing. You want all your room dimensions to not be multiples of each other, to prevent standing waves. I'd just go with a bunch of sealed 18" subs, unless you can design the IB really well so there is no way for flexing of the walls, or air leakage. You need to check very carefully about the electronic components you buy. Lots of components roll off at 5-10 hz, so you have to find specific components designed for like 2-3 hz roll-off.

If components roll off near 5-10hz, would a minidsp be sufficient to compensate?
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post #4 of 41 Old 08-01-2013, 07:02 AM
 
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If components roll off near 5-10hz, would a minidsp be sufficient to compensate?

Maybe a bit, but you should still try to get components with the lowest roll-off possible. I believe the miniDSP rolls off around 5 hz too. The problem is that if each component is -5 dB at 5 hz, and you have 6 components, you're -30 dB at 5 hz and I don't think you can compensate it enough, because you're going to want to be boosting that low quite a bit already to get it flat, because subwoofers roll off way higher than 5 dB. The room gain will also make up for the roll off, but if you are wanting really strong bass at 4 hz you will have to carefully pick your components. I know BassThatHz has spent a lot of money and time getting low roll-off components. Here's his dedicated room/theater build thread http://www.avsforum.com/t/1436049/bassthathz-theater-build
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post #5 of 41 Old 08-01-2013, 07:45 AM
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Thanks for the confirmation on when the miniDSP rolls off, I was going to start a whole thread to ask that smile.gif

I presume the miniDSP is like the BFD, in that you can apply a boost at a set frequency and then set how 'wide' the boost is?

So you could, in theory, apply a +3dB boost at 5Hz and have it 2 octaves wide, which I think would make it boost from 2.5Hz to 10Hz?

(If my understanding is correct???)
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post #6 of 41 Old 08-01-2013, 07:50 AM
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I'm trying to create an all purpose audio mastering room capable of incredibly low "infrasonic" bass response on what's actually a fairly low budget relative to the performance.

This is the part where I say, you are getting into something you will need some coin to accomplish. Just look at a few of the megabuilds around here, and still, they are not getting to 3hz at over 110dB's. Yes some of the graphs may show that, but only guys running aco-pacific mics like Bossobass would effectively be able to measure that low. REW and UMIK-1 are not going to be close to accurate that low. Some good examples of a direction to head are JapanDave's 8x REXXX18 IB build, Notnyt's 8x LMS Ultra sealed build, Andreas' slow rotary build (which hasn't had an update in a while, so I don't know about progress made there), or if you want to really look at a design if you are going to build a room around it, look no further than here:

http://www.youtube.com/watch?v=Zbf3bzpgml8

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post #7 of 41 Old 08-01-2013, 08:02 AM
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Quintuple rotary subs in a refrigerator sized room maybe......

Or, Quintuple XXX18s or LMS18s in an enclosure helmet that you can stick you head into, seal and wear should get up there too.... Call it the Dub Hat.

JK, man Do it! Might have to take on a second mortgage to do it though.....
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post #8 of 41 Old 08-01-2013, 08:21 AM
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What about a wall of LMS? Section a part of the room (length) for a wall to accomodate 16+ LMS speakers? Of course the wall (baffle) would be made out of something mega tough - as a proper baffle would be incredibly important... Maybe a few metal beam supports filled with concrete to avoid resonance. Then of course the 19" rack with a couple power amps with enough bang to provide that SPL level at 5Hz. I really just can't immagine the amount of pressure felt in a room +110dB @ 5hz.

I'm just speculating here... I have zero experience with infrasonic.
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post #9 of 41 Old 08-01-2013, 08:25 AM
 
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Originally Posted by MemX View Post

Thanks for the confirmation on when the miniDSP rolls off, I was going to start a whole thread to ask that smile.gif

I presume the miniDSP is like the BFD, in that you can apply a boost at a set frequency and then set how 'wide' the boost is?

So you could, in theory, apply a +3dB boost at 5Hz and have it 2 octaves wide, which I think would make it boost from 2.5Hz to 10Hz?

(If my understanding is correct???)

Haha don't take my post as confirmation, I just remember reading that it was 5 hz somewhere, I am not sure though.
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post #10 of 41 Old 08-01-2013, 08:59 AM
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Let's start with what exactly you mean by 130dB at 4Hz, and how you will determine whether you have met this condition or not.

If 4Hz is an arbitrary goal as you say (octave lower than 7-8Hz), you might as well just make it 3Hz and match the 3-120Hz LFE spec.

Doing this on 2kW is not really the best plan- fix that constraint and give yourself some options.

I'm just thinking out loud here, but here goes:

A room with the largest dimension of 23.5ft gives you gain starting at 24Hz. Theoretically you'll be +12dB at 12Hz, +24dB at 6Hz, and +36dB at 3Hz.

Sitting 4m back in the room (~13ft from the subs) will lose -12dB. Being in a corner, eighth space, should net you +12dB over ground plane (half space), and then -6dB if you want to look at 2m ground plane numbers which are common.

This leaves you roughly +30dB at 3Hz at the 4m away listening position in this theoretical room versus 2m groundplane measurements. This means you need a system capable of at least 100dB at 3Hz 2m groundplane.

If we look at Ricci's experiment here, it seems to jive in his 10 x 17.5 x 24ft example: http://www.data-bass.com/data?page=content&id=80

I'm making assumptions here without all of the information- like the fact that you would find CEA-2010 Max Burst acceptable to meet your 130dB mark?

Taking a decent cheap ($/displacement) 18" driver as an example, the Stereo Integrity HT-18D2, I'm figuring you'll get about 65dB at 3Hz 2m groundplane cleanly.

This means you'll need a wall of 64 of these with enough power to drive to full excursion to hit 130dB at the LP. So clearly, this is an ambitious endeavor.

Now, we're also talking about +15dB over reference LFE spec with a theoretical full 0dBFS signal burst at 3Hz. No film has ever had or ever will have this (likely).

So let's say you wanted to be able to hit 115dB (reference) at 3Hz for that theorietical 0dBFS signal burst that is unlikely to happen, just because you want to say you can. Now you only need 16 of those SI 18's, an entirely realistic build.

8 of course, powered capably, would give anyone enough horsepower to reproduce reference infrasonics that actually do exist. cool.gif

I'm making the assumption that electronics are flat down to 3Hz feeding the system properly- only to set that aside as an obvious need for this solution, the rest is more of a head scratcher to me. 3Hz 130dB at LP is insane. biggrin.gif
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post #11 of 41 Old 08-01-2013, 09:13 AM
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Believe it or not the hard part of this is getting electronics that do not roll off until below 3Hz. The more pieces you have in the signal chain the worse it will get. Often you will have the media player, the processor or avr then an EQ unit which is basically required for a shelf boost to bring up and flatten the low end. Finally you will have the amplifier. So you end up with the collective roll off of 4 units. There are ways to drop this down to three or even two units but they often involve compromising somewhere else. The best way may be to use a HTPC with a built in DSP suite which is then sent straight to amp. Or HTPC to amp with DSP built in...either or. My system will come close to 130dB at 5Hz but because of my electronics the output dives off a cliff after 7Hz. Eventually I want to improve my signal chain but it isn't a huge priority at this point.

From there it is a matter of sizing a bass system of either IB drivers or sealed bass modules and plenty of power for the desired space and output levels. Depending on the size of your room
8 Mach5 FTW21's in 6 cubes each with a pair of good power amps with robust ac lines to operate from should get you in the ballpark.

For a boost circuit or LT you should look at the marchand bassis. You will also require some decent measuring equipment for system verification and tuning.

All in you are probably looking at $8k to $10k for this type of bass system.
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post #12 of 41 Old 08-01-2013, 09:55 AM
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ALL of your questions have been answered already 3 or 4 times at least. Read the post above by Ricci (which has already been addressed several times) and the info below, which I posted in the diyaudio thread back in the beginning of May (which has also been addressed several times), and you will see all the answers you continue to seek. (I added some bold to the last paragraph since you really need to do some research and simulations on your own or you aren't going to learn anything. I also added some details in italics that were addressed in previous posts but not specifically in this one.)

post from diyaudio, May 4, 2013

I know you don't want concrete walls and ceilings but you need them. Do you know what a paper bag looks like when you put it up to your mouth and breathe into it? That's what your walls and ceiling are going to be doing if they are not thick concrete. Do you know how much energy it takes to accomplish that? That is all energy that your system is losing, in other words, it's using a huge amount of energy to move your structure instead of making clean bass sounds. You can make a room within a room if you want but the outside shell absolutely needs to be as solid as possible if you have any hope at all of being able to even perceive 4 hz.

The rigid fibreglass I am referring to is Owens Corning 700 series. Here's an example. Owens Corning 703 1 inch acoustical panels - 12 Panels at best prices - www.TMsoundproofing.com
It's very expensive and very effective. I have no idea how straw stacks up in terms of sound absorbtion and I don't care to research it, so that's up to you.

You only need to absorb through the modal region to take care of the room modes. The lowest modal frequency of the room is determined by the room's longest dimension. It's probably not cost effective or size effective to try to damp the lowest mode, for a large room it could be at 30 hz or lower. No matter what you do, you won't be able to fit enough straw in the room to affect 4 hz (unless you pack it so full you can't enter the room), so don't worry about that.

added details already addressed but not specifically in this post - you might want to use helmholtz resonator traps to absorb room modes (at least the lower ones) since they will be much more effective and space efficient than straw

quote from doggyboy - I've seen some designs that for instance the front of the room is 10ft wide the rear is 13ft wide, the front is 7ft tall the rear is 9ft tall, so that there is no "resonance" even essentially possible.

This is simply not true. There are always resonances. Making irregular shapes will break the resonances up so they don't all occur at the same frequencies. A circular shape is worst, it will have all equal dimensions and the resonance will be a narrow spike at only 1 frequency. Using irregular shapes will break that one strong resonance into many weaker resonances.

quote from doggyboy - For room size (from "what a guy") that under 20hz room size doesn't matter so much anymore if it's airtight...



That's the pic I posted earlier. The frequency range of interest is 4 to 20 hz, so as you can see, it doesn't matter how large the room is, in the range of 4 to 20 hz the room needs to be huge to make any difference at all.

(Graph 1 and 3 are rooms with a longest dimension of 6 feet, the second graph is a room with longest dimension of 20 feet.)

The room dimensions affect the room gain, and since the most important frequency is the lowest frequency, and since the room gain at 4 hz is the same whether the room is 6 feet long or 20 feet long, the dimensions don't really matter all that much.

By 20 hz you can see we've already lost 6 db in the larger room (comparing graphs 1 and 2), so it's not like the dimensions make no difference at all, but at single digit frequencies the dimensions don't make much difference (1 db at 10 hz).

I hope that is more clear now.

added details not included in original post, these details were explained in previous posts - graph 3 shows the effect of having an airtight room with perfectly rigid walls, the first 2 graphs show 50 percent leakage and therefore not nearly as much room gain

On a final note, it is absolutely essential that you get a working computer up and running. We can answer questions about IB response, sealed box response, horn response, room gain, pressure gain, etc, all day long and you aren't going to understand anything until you see and experience it yourself. Simulators are the best education you are ever going to get, it will bypass a lot of reading and conversational misunderstandings. You need to see for yourself how excursion is affected by tuning, how spl is affected by having an airtight room, how a 21 inch low excursion driver compares to an 18 inch high excursion driver. We can answer those questions with 100 percent accuracy but you won't really get it until you see it on a graph. The alternative is to learn the equations and do the math but the simulators make it so much easier.
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post #13 of 41 Old 08-01-2013, 10:07 AM
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i suppose that it should not be asked why one would want to master in content to 4hz when all the customers' systems will roll off before that.

one thing that you may wish to do is find somebody with a system as capable as you are shooting for and listen/sense it. that might help dial in how low and how loud your system needs to be.

also, having a "lossy" floor such as a suspended wooden platform hovering over the concrete slab may increase dramatically low bass sensations.

anyways, sounds like an interesting project...i'll be following along.

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post #14 of 41 Old 08-01-2013, 10:25 AM
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i suppose that it should not be asked why one would want to master in content to 4hz when all the customers' systems will roll off before that.

It's already been asked. (As has every other question you can imagine.)

When I suggested he take this project to avsforum I thought he might do that BEFORE we spent a lot of time at diyaudio answering all of his questions, not several months after. Diyaudio has been more geared towards pro style stuff lately so I thought it would be easier for the avs crew to answer the questions about ultra low (single digit) bass, suitable drivers, amps and other system gear, room gain, electronics roll off, budget considerations, etc. We did end up answering all his questions but apparently our answers were not good enough. Apparently he didn't even read them!?!
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(PS I still haven't caught up with every post in both places, i'm just starting this thread, so I can post a thread closer in each place directing future followups to here on AVSforum)
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post #15 of 41 Old 08-04-2013, 02:40 PM
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My system can play 3hz, as seen here:

This is -16db below clipping FYI.
Each 6db is a doubling of voltage and thus excursion (correct?).

My DAC is an Oppo 105 (USB mode) and the amp is a Sanway FP+ (aka LG clone amp).

So now you know what electronics to buy.... problem solved.

Now you just need to buy as many 18's and amps as possible and put it in an IB in the smallest room you can "live with".

As Beast was saying, the other problem will be the mic (aco-pacific?). I know the TermLab can 10hz and probably a good 160db, but it won't do the last 9 hz.

My system also has stereo bass + LFE channel routing (aka 7.3)
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post #16 of 41 Old 08-04-2013, 04:28 PM
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My system can play 3hz, as seen here:

)
ANY speaker can reproduce 1hz-even dome tweeters.

Just put a 1hz tone into them and watch them move in and out. No big deal.

Now how LOUD they can produce that freq is a TOTALLY different matter

But reproducing 1Hz is not big deal.

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post #17 of 41 Old 08-04-2013, 07:17 PM
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Originally Posted by BassThatHz View Post


Now you just need to buy as many 18's and amps as possible and put it in an IB in the smallest room you can "live with".

For reference, in post 1 of the diyaudio thread he mentioned a budget preference of $2000 with an absolute limit of $5000 for EVERYTHING. And later on he mentioned that he is strictly opposed to having concrete walls. Also, this is to be built inside a barn, so I'm picturing typical barnboard construction with 1/4 inch gaps between the exterior wall boards and a drywall on 2x4 frame shell inside.

I spent quite a bit of time trying to convince him that rigid boundaries (walls, ceiling, floor) and as airtight as possible is necessary. (See pics regarding room gain vs room size vs leakage in my post above.) A small room (within reason, and considering the already smallish size of average domestic rooms) is not nearly as important as an airtight room with rigid boundaries. Smaller is easier to pressurize of course, but only if it's sealed. The type of construction he wants to do is going to be almost impossible to pressurize.
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post #18 of 41 Old 08-04-2013, 07:20 PM
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Quote:
Originally Posted by Ivan Beaver View Post

ANY speaker can reproduce 1hz-even dome tweeters.

Just put a 1hz tone into them and watch them move in and out. No big deal.

Now how LOUD they can produce that freq is a TOTALLY different matter

But reproducing 1Hz is not big deal.

I think he's referring to LF roll off in most consumer electronics which is a big problem for a project like this (as per Ricci's post above).
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post #19 of 41 Old 08-04-2013, 07:28 PM
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he could probably find a used old van that could serve as a "demo room". that way no construction would be required and with the huge gain, cost could be kept low.

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post #20 of 41 Old 08-04-2013, 07:39 PM
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post #21 of 41 Old 08-04-2013, 10:18 PM
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Quote:
Originally Posted by Face2 View Post

This thread reminds me of an episode from Dark Matters: http://en.wikipedia.org/wiki/Vladimir_Gavreau

http://journal.borderlands.com/1996/the-sonic-weapon-of-vladimir-gavreau/

I'm not familiar with Dark Matters but I am familiar with that article. It's almost purely fiction and gets more and more fantastically absurd towards the end. It's clear the author of the article doesn't understand the subject matter at all. Take this quote for example - since when is 150 hz considered infrasonic?
Quote:
The infrasonic foghorns could produce a frightening two kilowatts of infrasonic energy, at a pitch of one hundred fifty cycles per second.

Here's a more rational look at the facts - http://www.diyaudio.com/forums/subwoofers/236529-subwoofer-too-far-history-lesson.html#post3504399 - read the whole thread, Danley gets involved too (very briefly).
Quote:
"A whistle 1.3 meters in diameter produced an infrasonic pitch of 37 cycles per second. This form violently shook the walls of the entire laboratory complex, though its intensity was less than 2 watts infrasonic power."
From Deadly Sounds - Dr. Vladimir Gavreau

It is of historical interest how much overstated the effects of "infrasonic power" were by the good doctor.

2 acoustic watts is 123 dB SPL.
37 Hz is not considered "infrasonic" this century.

Josh Ricci's Gjallerhorn can do an order of magnitude louder than that indoors an octave lower.

My Keystone sub, half the size of the Gjallerhorn, can do well over 133 dB (more than an order of magnitude louder than Vlad's "deadly sounds") at 37 Hz in a small room.

In any city in the world you can hear automobiles going by with LF at much higher SPL inside than anything achieved by Vladimir Gavreau. They may be annoying, but they certainly are not deadly.

If loud LF sounds were deadly, every astronaut would have succumbed on the launchpad, where levels of 150+ dB at a few Hz are experienced on every takeoff.

Art
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post #22 of 41 Old 08-05-2013, 01:33 AM
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post #23 of 41 Old 08-05-2013, 10:45 AM
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Cool thread. Ambitious goals!

Do it man...

Building awareness for the infrasound cause!
http://www.linkedin.com/groups/Home-Theater-Infrasound-Reproduction-4991800?home=&gid=4991800&trk=anet_ug_hm

We has some interesting conversations with Marc Fishman aka Filmmixer about this over at the DB forums.

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post #24 of 41 Old 03-03-2014, 11:45 AM
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hey,

i am a journalist and very interested in infrasound in films, too. Can you tell me where I can find exactly that conversation with Marc Fishmann /Filmmixer? Thank you! :-)

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post #25 of 41 Old 03-03-2014, 12:49 PM
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I removed a floor heater in my house over the weekend and discovered a 5'x4'x3' concrete bunker. Maybe I should pick up some headphones and 4 ib318s....
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post #26 of 41 Old 03-03-2014, 01:07 PM
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homeomnimax, could you share titles and sources with this nice infrasonic sound ? 4Hz Waterfalls would be nice 🍹 Thanks !!
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post #27 of 41 Old 03-03-2014, 01:13 PM
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Quote:
Originally Posted by Bombelman View Post

4Hz Waterfalls would be nice
Here, though I don't think even these do 130dB at 4Hz:

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post #28 of 41 Old 03-03-2014, 02:36 PM
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A guy in a white van the other day, told me this would do 130db at 4hz.
I was a little skeptical at first, but he really seemed to know his boom.


"The boom is dead, long live the bass"
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post #29 of 41 Old 03-03-2014, 02:53 PM
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^^^ Lulz. Those Pyramids be bangin man.

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post #30 of 41 Old 03-03-2014, 03:59 PM
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Quote:
Originally Posted by Fats Waller View Post

hey,
i am a journalist and very interested in infrasound in films, too. Can you tell me where I can find exactly that conversation with Marc Fishmann /Filmmixer? Thank you! :-)

Low Frequency content thread on DB site:
http://data-bass.ipbhost.com/index.php?/topic/12-the-low-frequency-content-thread-films-games-music-etc/
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