How do you know that? You've never posted the spectral distribution and total SPL of a single 32' organ pipe . . . (or of any of the other pipes in that rank).
Again, what you're saying is technically correct on paper, but not nearly as cut & dried in reality.
Of course the 1/4 wave rule is there, but it describes a continuum. The more we spread out our many boxes, the longer the wavelength (i.e. the lower the frequency) at which the rule begins to apply. Conversely, the more we smoosh them together, the less fun it sounds. But here's the thing: Even when they're jammed together fairly tightly, there remains a significant portion of the upper spectrum where the 1/4 wave rule does not apply, and this is important.
Remember that we're dealing with a very dense, complex sound, with myriad overtones and noises (yes, the wind noise gets sampled too!). It can be very "busy" in the upper register to say the least. When you take all these hundreds or thousands of sounds and mix them together electrically, the summations & cancellations are absolute and unflinching, all the way up the band - and it is precisely this difference that makes the whole thing sound like refried crap when you do this.
Obviously we want to spread out our boxes whenever space allows, but this isn't always the hand we're dealt. And while it certainly isn't optimal to stack them closely, I can tell you from personal experience that it isn't pointless or ignorant either. It does make a difference.
-- Jim
I know that because OP says it's inaudible at 16 hz unless he stands right in front of it and puts his hand on the box. Adding a port will add about 12 db, which is a bit more than a doubling of perceived level.
Perhaps you skipped the first 20 pages of this thread but this has been mentioned at least a couple dozen times. It's kind of the whole reason for this thread in the first place.
Even if it hadn't been thoroughly discussed to death it should be pretty obvious that a single 15 inch driver with 8 mm xmax in less than 10 cubic feet can't possibly compete with a real 16 hz pipe.
Also, who said a single pipe was appropriate for OP's organ? If it's a large organ several 16 hz pipes might be required to keep up with the higher frequency pipes. This little 15 inch driver can't compete with a single 16 hz pipe, it certainly can't compete with several.
Just a couple hours ago you said "Even the best speakers have very high distortion when driven at “organ” levels . . ."
Even though this isn't even remotely true if the speaker is sized appropriately this tells me that you know very well that you know a 15 inch woofer in less than 10 cubic feet (and most speakers used in this type of application) isn't going to be anywhere near adequate. Inadequate speakers lead to high distortion, adequate speakers don't have that problem.
If you want to prove I don't know what I'm doing you have to try a LOT harder than this. It appears you are arguing just for the sake of arguing. Please point out the errors I've posted and the concepts you think I don't understand that would prevent me from designing a system.
Perhaps you skipped the first 20 pages of this thread but this has been mentioned at least a couple dozen times. It's kind of the whole reason for this thread in the first place.
Even if it hadn't been thoroughly discussed to death it should be pretty obvious that a single 15 inch driver with 8 mm xmax in less than 10 cubic feet can't possibly compete with a real 16 hz pipe.
Also, who said a single pipe was appropriate for OP's organ? If it's a large organ several 16 hz pipes might be required to keep up with the higher frequency pipes. This little 15 inch driver can't compete with a single 16 hz pipe, it certainly can't compete with several.
Just a couple hours ago you said "Even the best speakers have very high distortion when driven at “organ” levels . . ."
Even though this isn't even remotely true if the speaker is sized appropriately this tells me that you know very well that you know a 15 inch woofer in less than 10 cubic feet (and most speakers used in this type of application) isn't going to be anywhere near adequate. Inadequate speakers lead to high distortion, adequate speakers don't have that problem.
If you want to prove I don't know what I'm doing you have to try a LOT harder than this. It appears you are arguing just for the sake of arguing. Please point out the errors I've posted and the concepts you think I don't understand that would prevent me from designing a system.
It's not a paper vs reality situation, the reason the rule is written on paper is because it accurately reflects reality. The 1/4 wave rule ALWAYS applies, what you mean to say is that once you space further than 1/4 wave apart the desired effect begins to apply, and that's going to start at a fairly low frequency (around 200 hz) even with a close stack. Still 16 - 200 hz neglects the first 4 octaves.
All I pointed out was that stacking 8 boxes tight up in the pipe room is not going to sound like spread out organ pipes.
It should also be noted that at some distance all these sounds blend together and what the all the acoustical interference adds up to at the audience distance is simply different frequency response, not an essential effect. ESPECIALLY when all the pipes and speakers are in a smallish room with close reflections off the walls and ESPECIALLY when the shutters are closed to damp down the spl.
Anyway, I'm pretty sure it's the spacious sound you like here, not the acoustical interference. Toole talks about this spacious sound quite a bit in his book, and advocates multi channel system over mono or stereo for exactly this reason. I'm pretty sure you are well aware of the sound you like, but not which actual attributes are causing the sound you like.
And it should also be mentioned that having 8 speakers closely stacked isn't any different than having 8 speakers in a single box, AND that unless each of the 8 channels is playing distinctly discrete and different information it makes no difference if you have 8 channels or 1 channel.
This is all pretty basic stuff.
I'm going to restate the fact that there are probably VERY few well designed church systems so it's likely that you've never heard a properly engineered system. It can be done fairly easily but it's going to take a large budget and a very good engineer.
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What is "pretty obvious" is that you don't know what you're talking about, and not much about "science" either. When you find out the spectral distribution and SPL of a real organ pipe in a 32' rank you will at least have learned something.
All of this should be fairly obvious to anyone that's played around with a good crossover simulator. The effects of interference at different frequencies and distances can easily be seen. At acoustically significant distances it's not an essential sound effect, it's just an altered frequency response.
Again, no facts, no technical info, no content at all except for a personal statement.
The question was "How do you know that?" (That it's not loud enough.)
This doesn't even require a technical answer. If you need to stand in front of it and put your hand on it to even perceive that it's on, it isn't loud enough.
You're stuck like a broken record on this question that I've already answered. There are several reasons why I know it isn't loud enough. OP said so and started a thread about it. How much clearer could it possibly be?
Now you add in spectral distribution to the mix too. How hard do you think it is to calculate pipe harmonics? And what does that have to do with anything? If you are just going to bring up random points and expect me to write a book for you on acoustics that isn't going to happen.
If you can't hold a technical conversation that's fine, but don't expect to ride this point to victory, this question has been answered dozens of times over by several different people already. I asked you to please point out the errors I've posted and the concepts you think I don't understand that would prevent me from designing a system.
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That, or many drivers since to do 16 Hz 'right' requires a total pipe diameter = ~1130/pi/16 = ~22.48 ft or a good size factory chimney, but obviously is impractical for any church, etc., though for what the OP wants to accomplish, i.e. just a 'fuller' bottom end, a SI HST15 end loaded 18" sonotube TL with 1500 W on tap sims 120+ dB/m at 16, 32 Hz should suffice and not having a very large footprint or be very expensive and made to blend in with a decorative cloth covering or even marble/whatever wallpaper, maybe could add a few more over time scattered around if budget permits to get the 'butt kicker' impact of a 'Voice of God' system.
GM
seriously guys. Hand me 8k and I will do this for you.
16 Stereo Integrity HT18s. 400 liters per box (yes, we are going to make a whole "wall" of woofers). tuned to 16 hz in a simple bass reflex and we are looking at 143 db at 1 meter, assuming we stick to the drivers RMS rating of 600 watts. considering 16hz is the only frequency of interest, and it is the excursion minima, as much power as you'd like can be applied (until you smell coil).
Lets look at cost of materials shall we
16 x 176 for the drivers = 2816
24 sheets of 3/4 baltic birch at 55 dollars, which is 15 more than I pay per sheet(overkill as hell) = 1320 dollars
pick your favorite 2 amps that can do 90 volts per channel into 2 ohms and have a ball. subs can be painted white and you've spent 4200 plus cost of amps, assuming you will *only* be feeding it the digital organ sample, you dont even need to process the box...
Now, truth be told, you dont need the bandwidth of a bassreflex box. you can build a simple 4th order bandpass for a massive peak at tuning (16hz) and likely get the same results from half the boxes and power.
16 Stereo Integrity HT18s. 400 liters per box (yes, we are going to make a whole "wall" of woofers). tuned to 16 hz in a simple bass reflex and we are looking at 143 db at 1 meter, assuming we stick to the drivers RMS rating of 600 watts. considering 16hz is the only frequency of interest, and it is the excursion minima, as much power as you'd like can be applied (until you smell coil).
Lets look at cost of materials shall we
16 x 176 for the drivers = 2816
24 sheets of 3/4 baltic birch at 55 dollars, which is 15 more than I pay per sheet(overkill as hell) = 1320 dollars
pick your favorite 2 amps that can do 90 volts per channel into 2 ohms and have a ball. subs can be painted white and you've spent 4200 plus cost of amps, assuming you will *only* be feeding it the digital organ sample, you dont even need to process the box...
Now, truth be told, you dont need the bandwidth of a bassreflex box. you can build a simple 4th order bandpass for a massive peak at tuning (16hz) and likely get the same results from half the boxes and power.
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Hello? That's pretty much exactly what I already said?
Again, it's not so cut & dried - it's another continuum. The more individual sound sources you use, the closer you get to the way the individual pipes sound. 2 speakers are better than 1, 4 better than 2, etc. But of course it's not going to sound the same. If you want it to sound the same, you stick with pipes. In lieu of that, you find a point on the continuum where your musical & practical requirements balance out.
We've already covered this. In the real world, separate sound sources do not produce the (distinctly unpleasant) intermodulation artifacts of an electrically summed & amplified (and non-linear to some degree) point source, especially when we're dealing with as complex a sound as this. Listening distance doesn't enter into it - with individual pipes, the problem is greatly reduced, and with a single speaker or two, the damage is done at the source of the sound.
You are of course correct about the spaciousness (or lack of same) in this scenario, but that's hardly what I was talking about. I've been talking mostly about intermodulation, and very little about spaciousness. Do you not get how obtuse and/or condescending your manner tends to be?
Is this not what we're discussing? The setups I'm describing definitely have different sounds coming from different speakers. Sometimes they double up some or all of the boxes for more SPL, but the main idea is different stuff coming out of different boxes.
Again with the condescension! You don't know me, or what I've heard or haven't heard. Your prodigious theoretical knowledge apparently affords you a large helping of contempt for those of us who have some experience with how this stuff actually works down here on the ground. "This is all pretty basic stuff," indeed.
I'm done here. I got other stuff to do. If having the last word is important to you, please knock yourself out.
-- Jim
Can someone post a mp3/wave of 16hz pipe organ registered in a song situation so we can see with for example audacity, what level at what frequency through the mix we're talking about with ?
Here's the last 10 seconds of Passacaglia and Fugue in C Minor (bwv 592) from the Great Organ at Methuen, courtesy of Michael Murray.
I can't get it to let me upload audio.
Edit: https://youtu.be/qj_oUK9jSBY?t=1718
28:38, but the url should put you at the right time.
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No, you said " there remains a significant portion of the upper spectrum where the 1/4 wave rule does not apply", which is actually the opposite, not exactly the same.
I'm simply disagreeing. I don't think the acoustical interference has much to do with anything. It does provide an altered frequency response of course but not much else at a distance. And of course distance has something to do with this, the distance from the sources that are interfering with each other determines what frequency response you hear.
I can show you exactly what happens with different sound sources interfering with each other acoustically. I can show you on a graph, I can show you with any given distance between the sources and any given distance between the listener and the sources. And I can tell you that it isn't ANYTHING except altering frequency response.
What can you show me to back up your opinion?
You are starting to sound like Deward, making personal statements with no content, no technical information. I'm LOADING UP my posts with technical information and talking on point, you guys just want to call me names and assume I don't know much about anything.
This is fine, I don't mind, but I'm doing a LOT more work here than you, step up your game.
I don't know you and I don't know what you have seen. You described it yourself as a big pile of snot.
I do know DSL does exactly this type of thing for a living and I doubt anyone would call their work a big pile of snot. I know if it can be done other engineers can do it.
You seem to have a disconnect with "paper" or "theory" and reality. People with prodigious theoretical knowledge know how stuff actually works on the ground. Where do you think the theory came from?
This is an equation, just like any other. It involves spl, dispersion, spaciousness and a bunch of other things we haven't discussed. There's no aspect of this that theory doesn't cover and suggesting that "stuff down here on the ground" works differently is probably your biggest obstacle.
Talking about acoustical interference as a unique sound effect that is vital to pipe organ presentation is a good place to start learning. In this forum (and acoustics in general) we deal with interference EVERY DAY. Drivers interfere with themselves through reflections, this is the cause of floor bounce, nulls in response in boxed drivers, and it's why some people line their first reflection points in home stereos. In multi way speakers the different drivers interfere with each other in EXACTLY THE SAME WAY you describe the pipes interfering. Our crossover simulators show us EXACTLY what the effect is, altered frequency response depending on distance between the sources and distance from listener to source. There's really nothing else going on, it's not a unique sound effect that does anything other than alter frequency response. And then we add a crossover to get rid of this effect because we don't want altered frequency response.
Pointing this out is NOT condescending, it's part of a technical conversation. At this point in the conversation it's your turn to back up your opinions with technical dialogue of your own, not with name calling and calling the other person condescending. You can do those things if you like and it won't hurt my feelings, but at least bring SOME amount of technical information to the table.
DrDyna,
Averaged over the 10 seconds it appears the upper harmonics are as much as 24 db or more louder than the 8 Hz fundamental in the particular piece you picked.
At 1000 Hz, an increase of 10 dB sounds twice as loud.
An interesting perception shift occurs down low, at 20 Hz it only takes a 5 dB increase to sound twice as loud.
Once the "threshold of feeling" at very low frequencies occurs, it takes just under a doubling of speakers and power to sound/feel twice as loud. Although there seems to be a large variation in SPL level where people hear, rather than feel VLF, it takes surprisingly little SPL to get the feeling of "weight" the long pipes can produce.
As an example, I have chose to move from certain seating positions in restaurants where I have perceived (and measured) LF tones of around 8-16 Hz from the air handling system. Those tones were probably less than 70 dB, reading only just above 60 dB on the "C" scale of a dB meter, yet I find exposure to that level disturbing after just a few minutes of exposure.
So although reproduction of the 8-16 Hz range certainly adds realism and "weight" to a pipe organ, from what I have heard of them I don't believe it necessary to design the VLF section of a pipe organ emulation for equal level as the 60-100 Hz range to achieve realistic results.
Art
Oh, absolutely...one of the situations I hate is being in a car with a window cracked at highway speeds.
Makes me crazy!
The other part of this though, is that even though the lower tones might be significantly lower in level, they seem to provide a "vibrato" of sorts for the other notes..so missing them not only misses them, but leaves out that interesting harmonic effect..I'm not even sure what to call it.
Edit: The other thing too, I'm not sure because I can't read music, but we don't know for sure what the organist was asking from the volume pedal, either..it may just be that he had the pedal ..."pedal" depressed 3/4ths of the amount of the great/swell/choir.
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The 8hz fundamental is interesting, but what do you know.... the 32hz harmonic is almost 20DB!!!! hotter than the 16hz fundamental....
Which is interesting too, as I'm 99% sure that organ's largest pipe is 32', so the 8 cycle has got to be some kind of inter-modulation effect, eh?
This is a good point, but I'll take this opportunity to restate and emphasize the point that if you have to stand right in front of the 16 hz box and put your hand on it to perceive that it's even on, it's several orders of magnitude too low.
GM's suggestion would add 20+ db to the current situation, but starting from essentially nothing (as described by OP) I don't think it's anywhere near enough. It's certainly a good start though, although I don't see HST15 on the site, perhaps HST18? But it's a $540 driver, that alone is more than the entire budget.
There's a lot of good drivers up in that price range, but with the "affordable" longer excursion drivers comes (much) higher inductance and that's going to make reaching the higher frequencies a lot more difficult, requiring either a lot of eq or a 2 way solution. If you want to produce a whole rank of pipes AND all their harmonics you need to reach up pretty high.
Lots of things to consider. This is the HST native response in 4.2 cu ft sealed. The HT is a lot cheaper and doesn't perform quite as well in terms of sheer spl but it's response is a bit less inductance-y. Not a lot better but a bit. This type of long excursion driver doesn't measure anything like a pro driver, but if you want long excursion on a budget this is what you get for your money. The hump at 45 hz and the rolloff above that are inductance related, the spike and dip above that are an undamped box resonance. The spike and dip at 3 and 4 hundred hz could be easily dealt with by box design and/or stuffing so it can be ignored, the inductance issue (the big inductance hump at box resonant frequency and 10 db down at 1 khz) not so much. Eq will fix it IF the driver can handle the power it takes to bump up the higher frequencies, otherwise you need a 2 way to cover it all.
An externally hosted image should be here but it was not working when we last tested it.
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But those effects can be sythesized, can they not? Adding 8 Hz IM products to all the other content in a DSP is a whole hell of a lot easier than trying to do it with a moving coil loudspeaker coupled through the air. Perhaps the organ maufacturer knows this.
This is a good point, but I'll take this opportunity to restate and emphasize the point that if you have to stand right in front of the 16 hz box and put your hand on it to perceive that it's even on, it's several orders of magnitude too low.
GM's suggestion would add 20+ db to the current situation, but starting from essentially nothing (as described by OP) I don't think it's anywhere near enough. It's certainly a good start though, although I don't see HST15 on the site, perhaps HST18? But it's a $540 driver, that alone is more than the entire budget.
There's a lot of good drivers up in that price range, but with the "affordable" longer excursion drivers comes (much) higher inductance and that's going to make reaching the higher frequencies a lot more difficult, requiring either a lot of eq or a 2 way solution. If you want to produce a whole rank of pipes AND all their harmonics you need to reach up pretty high.
Lots of things to consider. This is the HST native response in 4.2 cu ft sealed. The HT is a lot cheaper and doesn't perform quite as well in terms of sheer spl but it's response is a bit less inductance-y. Not a lot better but a bit. This type of long excursion driver doesn't measure anything like a pro driver, but if you want long excursion on a budget this is what you get for your money. The hump at 45 hz and the rolloff above that are inductance related, the spike and dip above that are an undamped box resonance. The spike and dip at 3 and 4 hundred hz could be easily dealt with by box design and/or stuffing so it can be ignored, the inductance issue (the big inductance hump at box resonant frequency and 10 db down at 1 khz) not so much. Eq will fix it IF the driver can handle the power it takes to bump up the higher frequencies, otherwise you need a 2 way to cover it all.
See my suggestion on the last page of 16 SI HT18s JAG.
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