Bach On,
No, since the overtones, partials, and wave shape are different, the bandwidth can't be the same.
Art
Hi Ben, another post completely devoid of anything technical, I see. Are you ever going to answer the leaky sealed box question or has that got you completely stumped?
The only difference between PRODUCING and REPRODUCING is that reproducing generally requires a faithful reproduction of the signal and producing generally does not want anything close to a faithful reproduction. BOTH producing and reproducing systems work with the same physics and acoustic science.
Sound IS sound. There is not a separate physics handbook written by God that only applies to pipe organs. Just because you don't understand the principles doesn't mean that pipe organs are magical. Sound IS sound. The same physical rules ALWAYS apply.
I already explained to you IN DETAIL in a different thread a year or two ago why your system doesn't sound real unless you are tightly glued to the sweet spot. At the time you had massive timing errors between the different drivers and cabs (some of which has been fixed now), AND your 1 meter square mains have absolutely horrid dispersion characteristics AND the mains cause an incredible amount of interference with the tweeter panels.
There's absolutely NO WAY your system can sound realistic at any point outside the sweet spot, and the sweet spot is extremely small, much smaller than the sweet spot in most well engineered systems. If you move your head an inch freqeuncy response is going to change.
You ignored this in the past, you are going to ignore it again. But I just gave you a bunch of technical reasons why your system is badly engineered and will NEVER pass the "down the hall" test.
I even pointed out to you that Toole's book DISAGREES with almost every single aspect of your system. You might want to go back and read the book and the thread where we discussed this again.
You've made it exceedingly clear that you either cannot or will not hold a technical conversation. You keep saying I'm wrong but you can't even quantify the performance of a leaky sealed box in technical terms. You are WAY out of your depth on this forum.
And you can change that "probably" into a "definitely" or "definitely not" with a drill and $0.45 worth of pipe.
The bass response of that cabinet can only be improved by doing this, so there's nothing at all to lose.
There's no problem with that. You know a lot about organs.
But you are not an acoustic engineer by any stretch of the imagination, and this conversation is all about acoustical engineering. Take that for whatever it's worth.
You already said the differences were SUBTLE. So the differences really matter NOT AT ALL.
What's important here is the speakers are all playing mainly the same freqeuncies, they will interact, interfere, and sum.
If the pipe spacing in real life is completely random acoustically, the interaction and interference will be random so you can't possibly say a random interference pattern is a necessary requirement. Clumping a bunch of boxes together is also random.
The interaction amounts to nothing other than altered frequency response so it doesn't really matter if you sum the signals electronically or sum them by clumping a bunch of boxes playing ALMOST the exact same signal. They two methods of summing will sound different, but the difference is just an altered frequency response, not a required sound effect.
Think about it this way. If you played a single note through a single pipe of a pipe organ, would it stop sounding like a pipe organ?
Of course not, that's absolutely ridiculous.
In this case there's only one pipe playing so there's no interference at all except if you want to include Allison effect which is just reflections. If a single pipe STILL sounds like a pipe (and there's no way it won't, I don't think ANYONE can argue something that dumb) then there is NO requirement to set up a random interference pattern with loudspeakers that will only amount to a slightly different frequency response anyway.
Of course not, that's absolutely ridiculous.
In this case there's only one pipe playing so there's no interference at all except if you want to include Allison effect which is just reflections. If a single pipe STILL sounds like a pipe (and there's no way it won't, I don't think ANYONE can argue something that dumb) then there is NO requirement to set up a random interference pattern with loudspeakers that will only amount to a slightly different frequency response anyway.
I'm getting a little old to go dumpster diving for 6 inch abs pipe - though I may decide to try it anyway. Lowe's wants $35 for a 10 foot length of it.
I'll probably do the port. But it has to wait until I have the pipe and the time. And if the driver needs to be changed, the specs on the port will probably need to be changed too.
Bach On
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6 inch abs pipe is a very bad idea anyway. How are you going to cut a hole that it will fit tight into? If it's not a tight fit no amount or type of glue is going to hold it in place. There are ways to get it to stay if the hole isn't tight but they are not easy or pretty.
As I mentioned a few dozen times, 4 lengths of 3 inch abs is equal in cross sectional area to a single length of 6 inch abs. 3 inch abs is literally everywhere I look for free, and a 3.5 inch hole saw is very common, common enough that I can easily borrow one if I lose mine.
Also, it's really easy to make a port out of wood, and wood scraps are free too.
As I mentioned a few dozen times, 4 lengths of 3 inch abs is equal in cross sectional area to a single length of 6 inch abs. 3 inch abs is literally everywhere I look for free, and a 3.5 inch hole saw is very common, common enough that I can easily borrow one if I lose mine.
Also, it's really easy to make a port out of wood, and wood scraps are free too.
I'm getting a little old to go dumpster diving for 6 inch abs pipe - though I may decide to try it anyway. Lowe's wants $35 for a 10 foot length of it.
I'll probably do the port. But it has to wait until I have the pipe and the time. And if the driver needs to be changed, the specs on the port will probably need to be changed too.
Bach On
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At our local store they have them in 5 foot pieces as well, probably cheaper.
But yeah, the port can also be made out of wood...or something like round concrete forms.
Sonotube (concrete form tubes) works fine, and is a lot cheaper. If you make a mounting flange for it it's very easy to mount, and modify, as well. You'll probably want to staple a bit of hardware cloth across the opening, though, to keep the church mice out . . .
A box tunin frequency depends on the volume of air inside the box. Not the driver. The proper volume of air for a river is the important part.
Creating the largest ent size that is practical will give you the cleanest output from the enclosure.
You will hear pipe resonances fom four pieces of 3 inch pipe.
This is a tough ask for a normal loudspeaker design.
I know this because I have designed electronic divisions for pipe orans.
If you are married to a ported enclosure the biggest bang for your buck will be using the concrete pier forminng tube. I have used the effectively before.
If you want a hand in the best balance for a ported design drop me a line.
Creating the largest ent size that is practical will give you the cleanest output from the enclosure.
You will hear pipe resonances fom four pieces of 3 inch pipe.
This is a tough ask for a normal loudspeaker design.
I know this because I have designed electronic divisions for pipe orans.
If you are married to a ported enclosure the biggest bang for your buck will be using the concrete pier forminng tube. I have used the effectively before.
If you want a hand in the best balance for a ported design drop me a line.
The only reason we went there in the beginning was because it'd be easier considering the cab already exists.
By far the best solution would be a gjallerhorn, right? Just far more complex / expensive of a suggestion.
By best I mean replacing that one cab with one other cab of comparable size.
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Josh Ricci's design is well known. It is a comprimise in terms of box complexity and efficiency. I would shoot for efficiency. Josh designed to a box size.
In terms of ultimate output I have designed 4 18 inch driver horn loaded subs that could cracked 140 db in 4 Pi space.
It depends on the size of room that you want to get up and boogie in!
In terms of ultimate output I have designed 4 18 inch driver horn loaded subs that could cracked 140 db in 4 Pi space.
It depends on the size of room that you want to get up and boogie in!
If it'll fit into a 14 foot by 16 foot room and there's still room for a person, I'd definately put it into my "maybe someday" book, haha.
If you change the design from a 15 inch driver with 8 mm xmax and the design already has high(ish) velocity to an 18 inch driver with 20+mm of published xmax, velocity is going to go through the roof. THAT is the important part.
No you won't. I already showed a sim of the design, the resonances are up around 120 hz and higher and are very benign. If the resonances are audible at all (they won't be) a bit of stuffing in the right part of the cab will make the response curve smooth as a baby's butt.
This has already been discussed to death. Sims have been shown. Resonances are not a problem. Look at the info already published and don't cloud up issues that have already been resolved. If you want to disagree post your own sim that shows problems. Mine didn't have any problems.
Four pieces of 3 inch pipe is basically the same as one piece of 6 inch pipe (ignoring boundary layer resistance issues that are not really all that relevant).
This is not a tough job for a loudspeaker. This is about as simple as enclosure design gets.
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