If there isn't room for a set of pipes, there isn't room for a speaker. What makes anyone think that a speaker that can produce enough ocatve 0 to keep up with ocatve 1 will be any smaller than the pipes they replace?
You need to think about creative places to put the speakerS, that you may not be able to put physical pipes. In the crawl space/plenum space/attic? Under the foundation? In the walls?... You may be able to fit a full size horn in there somewhere out of sight. If you don't want a horn, it will take an equivalent cubic footage of standard reflex boxes.
The limit on output here is cone size and excursion . . . QTS is not really the issue:
Piston Excursion calculator
That's not quite true, but it is why you are seeing so many recommendations for a ported alignment (and if there were space a "corner horn" would be better still) . . .
Simply untrue. A rank of pipes that sounds from 16 to 64 (or 128) Hz. is HUGE. And (relatively) small subwoofers make (relatively) big sounds all the time.
It's nice to see the topic slowly getting more votes on the side of common sense and no more votes for sealed boxes.
From what I've been able to infer the budget is approximately $250, he was willing to buy an extra driver and four $35 PRs. That budget isn't going to do much considering the fact that 16 hz is completely inaudible at this point.
A port in the existing box is the best option by far, it will gain approximately 12 db at 16 hz for free, resulting in a bit more than doubling the perceived loudness at 16 hz. Adding another identical ported box and fully powering it will add another 6 db, for a total of + 18 db, almost 3x louder than the current situation. And that's still not even close to enough.
If OP doesn't have the construction skills to add a port to the box (he's mentioned several times that it's too difficult) I don't think horns are going to be in the cards.
I have not inferred that size is any issue here, even if it was he could ditch all those antique reconed woofer boxes that are completely useless at 16 hz and use the space for something that can actually make bass.
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Right, I agree that using the suggestion of adding the port will make it so that this cabinet can produce 16 hz. The problem is, at what level, 80-90 db nearfield?
So, then we realize that we're brick-walled right up against what's probably the maximum output of this subwoofer a few feet away from the cabinet, what does that mean for people sitting out in the room?
And then what's going to happen when the organist is suddenly filled with the spirit and flattens the volume and stomps on that 32' pedal?
RAGGETYGAHGAHGAHRAGGARRRRAGGGG......
Edit: Just so we're clear what we're talking about, this is the subwoofer in question, in case anyone missed the link.
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I've shown sims a few times, most recently just a couple of posts ago. About 105 db at 1 meter at xmax, a bit more if you ignore xmax and shoot for xlim.
Not 80 - 90 db for sure, but even 105 is still barely perceptible at 16 hz.
105 is a bit better at 1m...but what is that compared to the first real air driven pipe ..and then out in the middle of the room?
I think the volume would have to be so low comparatively that it might not be worth the electricity to run it.
Edit: I apologize, I have a terrible habit of pulling numbers out of thin air for dramatic purposes.
It's impossible to say what the room acoustics are going to do but sound decays at 6 db per doubling of distance outside with this type of speaker.
If this is corner loaded and the entire structure is built like a concrete underground bunker, that's a big difference from having it sitting in the middle of large room with drywall on 2x4 on vinyl siding.
All we can do is offer 2 pi predictions of performance and let OP sort out the room acoustics and number of subs required.
But I would tend to agree, even though porting the sub is overwhelming the best option considering all the different options that could be applied to this box, a single ported box is going to be vastly inadequate. A wind box feeding a massive pipe is more than a bit different than a relative small, relatively low xmax driver in a ported box.
If this is corner loaded and the entire structure is built like a concrete underground bunker, that's a big difference from having it sitting in the middle of large room with drywall on 2x4 on vinyl siding.
All we can do is offer 2 pi predictions of performance and let OP sort out the room acoustics and number of subs required.
But I would tend to agree, even though porting the sub is overwhelming the best option considering all the different options that could be applied to this box, a single ported box is going to be vastly inadequate. A wind box feeding a massive pipe is more than a bit different than a relative small, relatively low xmax driver in a ported box.
Speakers are air pumps (basically) and pipe organs have air pumps running through tuned pipes (basically) It CAN be done but--is the juice worth the squeeze?
I was in Italy around 25 years ago and stumbled across a pipe organ and that thing was LOUD! The organist would pull the stops and it shook the stone building. It did not have the 64 foot pipe, I think around 32 feet or 10 meters.
How much would it take to get a 16Hz level to work well with a pipe organ at full tilt? Using THX IMAX standards of 121dB at 20Hz at the seated position--switch it to 16Hz at around 121dB at the seated position. Consider the church is 100 feet long so a 30dB loss due to distance... 151dB at 16Hz.
I pity the fool sitting on the front row 10 feet away! 141dB at 16Hz would be very detectable.
I'd mount the massive sub array that could do that as high up the front wall as possible so to not blow out the front rows.
Getting out of theory and into reality--the SPL required to pressurize a 100 foot x 75 foot x 30 foot room at 16Hz is staggering. At that level, one must be concerned with the building getting damaged and a host of other issues.
Here is a thread about building four 18" SI subwoofers tuned to 16Hz. It will give you an idea of what they will do. One of them at around 1,000 watts is 116dB to 118dB at 16Hz. Each box is 40x44x20 inches or around 20 cubic feet external. My guess is four of those at 4,000 watts would be around 130dB?
The Official Stone Hammer Thread 4-20cubic foot boxes - AVS | Home Theater Discussions And Reviews
The SI HT18" drivers are around $800 for four of them shipped and throw in another $400 for the iNuke 6000DSP amp to power them. The wood and PL Premium glue (etc.) is extra.
Doing the math, that would be around 100dB at 16Hz at the back wall of the church. Figure around 120dB at 16Hz at the front row 10 feet away.
All rough guesses but it shows how wimpy subwoofers are compared to pipe organs running off compressors! If I was stuck in this project, I'd get a sound level meter and takes some readings during the performance to get an idea of the SPL required. Then figure out how much more SPL is required at 16Hz VS say... 32 or 64Hz and go with that.
As far as PRs go, I have one for my home theater. A single 12" driving a single 18" PR. The Sd of the 12" is 511 sq cm and the 18" PR is 1,182 sq. cm. The Xmax of the 12 is 15.5mm and the PR will hit 15.2mm at tuning.
That would be around 2.3 times the active driver in total displacement. The PR peaks at 20Hz and the 12Hz high passed 12 peaks at 16Hz. I was instructed years ago to go with 3 times the displacement of the active driver when using PRs for low tuned subs--good advice.
If you really want a sub system to match up with a pipe organ, I'd call Danley Sound Labs as they tend to lead in the field of LF. They might give you an idea of what would be required to meet your requirements.
I was just having a senior moment, I didn't imagine organs had electrical outputs and was imagining a midi controller glued to the side of the pedals or something.
Enclosed space acoustics is extremely unpredictable, there's no way to know how the room with affect the acoustics and all the rules go out the window. Sound does not decay at the usual rate of 6 db per doubling of distance in an enclosed space due to a lot of factors. Unless you know a LOT about the room, the room leakage and construction, the sound system and the sound system's placement in the room it's futile to even guess. Unless the room is large enough to approach acoustically open space for the frequencies at play it won't act like an acoustically open space.
If they know the budget is $250 I seriously doubt they would even return your call. Even if they did they couldn't offer any serious recommendation without knowing a LOT about the building, construction, and available locations to place the system.
Yep. Ballpark maybe, though. That said, there is a LOT of idle speculation going on here about how loud real organs in the real world actually are (especially the longer pipes, which actually radiate sound only from the openings at their ends). Amplified bands on stage can (and often do) simply overwhelm the installed organ . . . think about the implications of that . . .
Amplified bands on stage don't try to reproduce the 16 Hz. And they only try to get to 32 Hz if there is a very big budget for the speakers.
A couple of 2x15 full range to cabs going full tilt above 80 Hz will render anything coming out of a single subwoofer cab at 16 Hz completely inaudible. You might hear it if you turn off the rest of that racket 🙂.
A couple of 2x15 full range to cabs going full tilt above 80 Hz will render anything coming out of a single subwoofer cab at 16 Hz completely inaudible. You might hear it if you turn off the rest of that racket 🙂.
My math was a stab at giving an idea of what is required
It is not exact, when you have little to no information--just use known standards (IMAX THX for example) then go with raw numbers. The point is to get an idea of what you are dealing with as a "go/no go" situation.
To put it in a language everyone will understand, it is going to take a LOT of money to build a subwoofer system to mesh up with a pipe organ to produce 16Hz in a large church.
Danley Sound Labs provides free software to model the building and get an idea of what you'll end up with.
Danley Sound Labs Direct files | Danley Sound Labs, Inc.
Cameron Carpenter went on tour with a "virtual pipe organ" and you can get those notes with subs that weigh no more than 75 pounds--just takes quite a few of them but it can be done. Cost? If you have to ask....
It is not exact, when you have little to no information--just use known standards (IMAX THX for example) then go with raw numbers. The point is to get an idea of what you are dealing with as a "go/no go" situation.
To put it in a language everyone will understand, it is going to take a LOT of money to build a subwoofer system to mesh up with a pipe organ to produce 16Hz in a large church.
Danley Sound Labs provides free software to model the building and get an idea of what you'll end up with.
Danley Sound Labs Direct files | Danley Sound Labs, Inc.
Cameron Carpenter went on tour with a "virtual pipe organ" and you can get those notes with subs that weigh no more than 75 pounds--just takes quite a few of them but it can be done. Cost? If you have to ask....
It will do the same to the output of a single organ pipe (or two, or three . . .).
The typical goal in a hybrid organ is (usually) to make the electronic part sound appropriately proportional to the wind part (to which the synthesized low frequency stops will usually be coupled when played anyway).
What's really needed here is a single measurement of the SPL produced by one of the pipes in the lowest register of the existing wind organ. That might ground everyone's speculation about what is needed for the "electronic" register(s).
It's not really the same thing with those huge pipes, though. That 16 hz pipe, while generating that note, is also causing massive vibrato to other notes.
If you swap in a speaker to take the place of a gigantic pipe, it should be able to manipulate the air pressure in the room in close to the same manner, or a large part of the experience will be missing.
Edit: But yes, a spectrum of what's going on with spl would be a huge step forward in figuring out what's needed.
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What about a large (2 horsepower) electric motor geared down to 16rpm directly coupled to the floor and driven by a relay (or scr if you want more control) that clicks in when there's a low note. If that dosnt shake the place, try a bigger motor.
And the harmonics generAted will sound similar to a pipe. Everything in the church with a 16 hz or harmonic resonance will vibrate. If you want to shake the place then Literaly shake the place.
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