They can be, I suppose, but that adds a LOT of complexity for the sound samples, because if you're synth-ing the effect instead of allowing it to occur naturally because the fundamental is there, then not only do you need a sample of each note, you then need a separate sample for each note with every other note..so you have to add a mathematical "power".
I.E C on the choir sample would then require a sample for C alone, then for what C sounds like with low A, with low B, with low C, etc etc.
Edit: orrrr...maybe I'm crazy, idk. There might very well be a shortcut in DSP, but when I try to imagine it, I'd think it would be extremely difficult...I think the dsp doesn't currently account for path length differences, so...idk.
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Some napkin physics. A small blower motor of 20 hp =15000watts. Efficiencies of 30% (guessing this and making it similar to high efficiency speakers, but I don't imagine that much heat comming off the organ. ) so a ballpark for power amp is 15,000 watts. Depends Huge on organ efficiency. If it's 60% you'll need 30,000 watts. A large organ needs 300,000 watts. So large low end in a large space needs large power, no surprise there. These numbers suggest a large PA rig. Are a couple of subs really going to cut it?
Cbdb,
Your numbers are based on all the blower air going to the low pipes, which is not the case, the blower is sized to provide enough wind to blow multiple ranks all at once.
A couple of fractional horsepower Thigpen rotary fan subs were considered adequate for Cameron Carpenter's Telarc recording, though they could do 110 dB, 105 dB from 7 Hz to 25 Hz was considered to be tonally balanced with the rest of the system.
If you limit the LF extension to 16 Hz, those levels do not require a large PA rig or rotary subwoofers, but do require one or two high power, high displacement, low Fs woofers.
Art
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Yup, and it's a good suggestion.
People are suggesting that the 16 hz box needs to extend up to at least 200 hz though, to cover the whole rank of pipes and all the pipe harmonics (I haven't done the math myself to see how high it actually needs to go for this) and I'm just pointing out that these high inductance subs won't measure as simulated.
The HT18 has much milder inductance effects than the HST though, so it's a lot easier to work with.
Accurately simulating high inductance is pretty easy, I worked out a method for it and it's not 100 percent accurate but it's pretty close. Compared to measurements of sealed, ported, tapped horn and front loaded horn, mostly done by Josh Ricci (so you know they are accurate measurements), my high inductance sims are almost right on the money.
If I was shooting for 16hz for real, there's no way I would carry it up to 200hz... mist likely I would use a shallow sloped lopass (6-12 db/octave) around 50hz. As shown in Dr dynasty post, the 32Hz harmonic almost 20 db hotter... flat response of 143 db up to 200hz would clear the congregation VERY quickly.
Don't forget, 143 db at 1m isn't 143 db out in the room. I'd think 120db/1m would be more in line with what would sound decent and not be under any stress.
And no, I didn't shoot JR.
Numbers aside, a system capable of 143 db in passband at 1 meter is sufficient of providing "rock concert" levels of bass for venues up to 2k people.
I've never been to a "mega church" but most people I know over 30 years of age (this forum aside) find bass levels over 100dbc to be intimidatingly loud
I've never been to a "mega church" but most people I know over 30 years of age (this forum aside) find bass levels over 100dbc to be intimidatingly loud
Oh, true...but a speaker doing 120db near-field falls off pretty quickly out in the audience. The truth is, we won't know what's needed until we see some kind of measurement, but I can almost guarantee you, with the volume pedal pegged and all the stops out, at 1 meter from the pipes, that organ is probably hitting 110 or higher, at least.
At least a couple people have mentioned the box for this rank has to extend up to 200 hz minimum. So it doesn't matter how you do that, either a wideband driver or a 2 way.
But I'm with you, I wouldn't try to get a single driver playing 16 - 200+ hz. I'd split that up over 2 drivers.
Basically what the organ guys are saying is they want almost full range boxes (several octaves at the very least) for EVERY rank, and they want multiple boxes for EVERY rank so they can acoustically interfere with each other.
This seems really odd to me, and it's not how I would do it, and I can pretty much guarantee I'd get a better result in a much smaller package for a lot less money, but these guys want what they want...
I don't know, maybe the bigger box and all 8 little(r) boxes are all for the same rank. In that case those 8 little boxes shouldn't have any problem hitting 200+ hz.
Since the bigger box is crossed at 177 hz I just assumed the small boxes were playing a whole different range, but honestly I have no clue how he has it set up. Maybe he mentioned the details of this, I don't remember it.
Since the bigger box is crossed at 177 hz I just assumed the small boxes were playing a whole different range, but honestly I have no clue how he has it set up. Maybe he mentioned the details of this, I don't remember it.
Somewhere between a third and half right . . . (you're improving). More like "appropriate partial range boxes for as many ranks as might sound at any given time" and "distributed boxes within a rank if spacing better replicates the sound of separated pipes". For the more commonly played stops separate speakers for the rank's octaves gives a richer sound.
The speaker that sounds the 32' stop will sound notes with fundamentals ranging from 16 to 64 Hz (it's unlikely to be more than two octaves, there are other stops for that) and will only rarely sound more than two notes at a time, never more than three. If it's coupled only to the pedal more than one is unlikely. Since one generally wants up to at least the fifth harmonic (higher for a reed stop) that speaker needs to reproduce a frequency range from 16 to at least 320Hz . . . a range easily covered by common bass drivers. The large pipes in particular sound with more energy in the harmonics than the fundamentals, something to keep in mind when looking at SPL and excursion limits.
At the upper end the lowest note in a 4' rank is 128Hz and the highest maybe 2048 but probably 1024, but the higher harmonics are unlikely to be masked so a somewhat more extended high frequency response is desired . . . those speakers should be good to 10kHz. but don't need much on the bottom.
For those of you with delusions about how loud an organ is, remember that in churches it supports the choir, it doesn't overwhelm it. In concert a single stop on a small baroque organ playing continuo about matches a bassoon or string bass, and the "trumpet" stop is no louder than a real trumpet (and maybe not as loud). When Mozart wants attention in the C minor Mass it's the trombones and trumpets that get it, not the organ.
The purpose of the organ is not to drive people out of the hall . . . in the real world they're not as loud as hi fi nuts like to play their recordings.
Ps. for a little gedankenexperiment . . . generate two sine waves, equal amplitude and frequency, 180 degrees out of phase. Combine them electrically and send them to one speaker. Then send them separately to two speakers. Sound the same?
Well I never claimed to be an expert on traditional organ pipe electronics, I only said that I understand acoustic science and I could make a system to electronically produce the sound. I still say the traditional way of doing things sounds pretty dumb and I think you guys are seriously misunderstanding the importance of this acoustic interference.
What does "richer" mean? More spacious? If so, that's no surprise, spread the sound and it sounds more spacious.
Yeah, good luck with that. OP has a driver that easily covers this range, and it has 8 mm xmax. At full tilt he has to stand in front of it and put his hand on it to perceive it's even on. If you want a driver with enough displacement to actually be usable at 16 hz it's not going to be a common bass driver and it's not going to be cheap if you want it to cover more than 4 octaves. There are VERY few drivers that can do both and they are VERY expensive. You can use multiples of regular drivers of course, but box size and budget is going to get out of hand very fast.
Who is that exactly? My old church had an organ and it wasn't that loud, you could communicate over it in a loud whisper. That has nothing to do with the fact that OP has to stand right in front of his box and put his hand on it to perceive that it's even on.
What's the point of this little experiment? I don't have to perform it to know what happens in both situations. Doesn't the fact that I know one cancels perfectly and the other doesn't tell you that I understand very well the concepts at play?
Try a little experiment yourself. Take two drivers, doesn't matter if it's a couple of mids or a mid and a tweeter. You can even use the drivers in your home speakers if you want if you remove the crossovers. Pick a frequency that both drivers can produce well, and at approximately at the same spl level. Play a sine wave of equal amplitude and frequency IN phase. Listen to it from a bunch of different angles and distances. Does it sound more spacious than a single driver? Does it sound like a sound effect that an organ pipe NEEDS to sound realistic (apart from just sounding more spacious), or does it just sound like altered frequency response? At close distances do you get a big notch in response at certain frequencies related to your listening angle? At large distances does it all just mix together into a single blob of sound that doesn't change much regardless of listening angle?
If you answer no to the sound effect question and yes to the others you're improving.
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I source my delusions from an article posted by the Archdiocese of Washington.
The Inner Life of the Pipe Organ – King of Instruments! Archdiocese of Washington
"When I was young and in high school I was a rock ‘n’ roll fan. It had to be loud and in your face. Then one day I walked into a large church and the organist was practicing with all the stops pulled. The loud organ shook the building and resonated through my very body. I was hooked! I said, “I have to learn to play that!” And I was off on my adventure. Alas, I am no virtuoso but I can play hymns well and I do all the footwork. I love to play the organ and make the whole build shake with the big 32 Foot in the pedal."
My thoughts on the homemade bass speaker was to let it carry the low sounds for anything sent to it. I'd probably define that with the crossover to anything below 64 hz.(2 octaves). I've mentioned that one or two Allen HC12s would probably be assigned the task of handling pedals too. These speakers are full-range with woofers, dual mid-range speakers and a dome tweeter. The evidence is that they can handle sounds down into the range of 30-40 hz., but with at least some roll off. Remember that the bass speaker and the HC12 (one or two) operate on different amps. and different stereo channels. So the signal to the HC12 could be sent via the crossover with only pitches above 64. Or, another frequency could be selected. It may turn out that no crossover is used for the box or boxes on this channel. This project is not plug-n-play.
The sound module operates using software that allows note-by-note adjustment of every voice. So a hump at 20 hz. could be handled using the software. Some slight increase where sounds are lost are also possible - but clipping, distortion and cone excursion may limit this.
I remind you that the overall plan is to send specific sounds to no more than two speakers at the same time for most of the sounds. That means there will be no time in which more than one stereo pair of speakers are actually playing the same samples. One pair might be playing an 8 foot flute at 200 hz. And another pair might be playing an 8 foot principal at 200 hz. But the same speakers won't be playing both the Flute and the Principal. There may be some exceptions to this. But that is the overall goal.
The speakers will be in a relatively compact area. There's no disagreement that being able to space them further apart would be better. I HOPE to be able to angle the drivers off center (at different angles - L & R and UP & Down) to achieve at least some dispersion. Justaguy has made the point that using smaller boxes would allow the speakers to be spread out within the pipe chamber. We got some additional speakers with the HC12s. These have the same Peerless 4 inch mid-range (1) and the dome tweeter (1). We have eight of these units.Putting them inline OR in place of some of the HC12s is possible. Such decisions will be made in voicing the organ. Some channels might have one of these. Others may not need them.
Frankly, I feel some of you are imagining that the sonic levels of the 16 hz. "sounds: need to be as loud as the other sounds. My unscientific approach is to first get the mid-range and high sounds balanced. Then I gradually begin to add the lows. I know people who do the bass first. And I know people who do both at the same time. I also know people who like a lot more bass than I do. And I know people who like a lot less.
I'm struck by the use of the words Interact and Interfere. Pipes interact with one another. It is planed and is part of the design goals. Our hope is to have the speaker sounds also interact with all the sounds produced in the pipe chamber. Out of phase issues would cause speakers to interfere. I'm hopeful our connections will not suffer from that. I'm hoping for healthy and lively interaction.
Justaguy has looked at pics of organ pipes in their pipe chambers. He's noted (ahem) that the arrangement of individual pipes within a rank seems somewhat haphazard. There is truth in that.
Let's take a few notes on a keyboard, reading from left to right:
C, C#, D, D#, E, F, F#, G - I'll stop there. Each of the pipes in a rank for these notes have a different lengths. Remember that all the pipes of one rank sit in one or more receivers full of air. There are solenoid valves beneath each pipe. Wires connect to each solenoid valve. Some pipe builders seem to favor one arrangement of the pipes in their receivers. Other builders seem to favor another arrangement.
Example: Bubba B. Organ favors this pipe arrangement:
C on far left (it is the longest pipe in that rank). The C# sits right next to it (next longest) so the pipes appear from longest to shortest like stairsteps from left-to-right.
He likes this because it is the same as the notes on the keyboard. He finds it less confusing in doing the wiring from the keys to their corresponding solenoid valve. It also helps when he and his technician come back to tune the organ.
Jerry J. Jorgana uses a different pipe arrangement.
He puts C on the far left. Then he puts C# on the far right. Going back to the left, Jerry next puts the D, the D# is on the other side, just left of the C#. He's used that method for years..
Marvin M Morgan uses yet another approach:
He puts C in the middle of the receiver. C# is the next pipe to the left of C, Then D is placed to the right of C. So the pattern alternates both sides from the tall C in the center to the shortest pipes of the rank on the ends.
Sometimes one approach is used by these builders is consistent throughout the organ. But sometimes it isn't.
Remember the old Revolutionary War battle scenes where ranks of soldiers would march out onto the battlefield. The first row would kneel down, while the second row fired, then the front rank would rise and fire while the second rank reloaded. The front rank kneels to get out of the way and not "INTERFERE" with the shooting of the soldiers of the second rank.
Sometimes when there are rank after rank of pipes in one area, the pipes are arranged so there slightly larger gaps or areas through which the sounds can travel.
On historic organs, sometimes additions of pipes may be installed by different organ builders. If Bubba B. Organ has died, Marvin M. Morgan may perform the additions. He may copy the arrangement Bubba used. But he may not.
Organists are familiar with these different arrangements of pipes found on individual organs. The difference to the listener may seem slight, but it can be heard. Newer electronic organs now allow the organist to program the arrangement of the pipes by individual ranks. Our sound engine allows this.
Again, probably more than you want to know.
Bach On
P.S. Justaguy has mentioned about 10 or 15 times my statement that I could detect vibrations on the bass speaker at 16 hz by standing in front of it and placing my hand on it. Clearly, he takes this as evidence that the speaker could not adequately produce the 16 hz. "sounds".
Question: can everyone hear sounds below 30 hz. equally?
DrDyna has said, I believe, he can hear sounds well down below 16. Many other people cannot. Maybe I couldn't hear it because I'm one of those people?. Maybe the speaker was doing it, but it was simply outside MY hearing range.
The sound module operates using software that allows note-by-note adjustment of every voice. So a hump at 20 hz. could be handled using the software. Some slight increase where sounds are lost are also possible - but clipping, distortion and cone excursion may limit this.
I remind you that the overall plan is to send specific sounds to no more than two speakers at the same time for most of the sounds. That means there will be no time in which more than one stereo pair of speakers are actually playing the same samples. One pair might be playing an 8 foot flute at 200 hz. And another pair might be playing an 8 foot principal at 200 hz. But the same speakers won't be playing both the Flute and the Principal. There may be some exceptions to this. But that is the overall goal.
The speakers will be in a relatively compact area. There's no disagreement that being able to space them further apart would be better. I HOPE to be able to angle the drivers off center (at different angles - L & R and UP & Down) to achieve at least some dispersion. Justaguy has made the point that using smaller boxes would allow the speakers to be spread out within the pipe chamber. We got some additional speakers with the HC12s. These have the same Peerless 4 inch mid-range (1) and the dome tweeter (1). We have eight of these units.Putting them inline OR in place of some of the HC12s is possible. Such decisions will be made in voicing the organ. Some channels might have one of these. Others may not need them.
Frankly, I feel some of you are imagining that the sonic levels of the 16 hz. "sounds: need to be as loud as the other sounds. My unscientific approach is to first get the mid-range and high sounds balanced. Then I gradually begin to add the lows. I know people who do the bass first. And I know people who do both at the same time. I also know people who like a lot more bass than I do. And I know people who like a lot less.
I'm struck by the use of the words Interact and Interfere. Pipes interact with one another. It is planed and is part of the design goals. Our hope is to have the speaker sounds also interact with all the sounds produced in the pipe chamber. Out of phase issues would cause speakers to interfere. I'm hopeful our connections will not suffer from that. I'm hoping for healthy and lively interaction.
Justaguy has looked at pics of organ pipes in their pipe chambers. He's noted (ahem) that the arrangement of individual pipes within a rank seems somewhat haphazard. There is truth in that.
Let's take a few notes on a keyboard, reading from left to right:
C, C#, D, D#, E, F, F#, G - I'll stop there. Each of the pipes in a rank for these notes have a different lengths. Remember that all the pipes of one rank sit in one or more receivers full of air. There are solenoid valves beneath each pipe. Wires connect to each solenoid valve. Some pipe builders seem to favor one arrangement of the pipes in their receivers. Other builders seem to favor another arrangement.
Example: Bubba B. Organ favors this pipe arrangement:
C on far left (it is the longest pipe in that rank). The C# sits right next to it (next longest) so the pipes appear from longest to shortest like stairsteps from left-to-right.
He likes this because it is the same as the notes on the keyboard. He finds it less confusing in doing the wiring from the keys to their corresponding solenoid valve. It also helps when he and his technician come back to tune the organ.
Jerry J. Jorgana uses a different pipe arrangement.
He puts C on the far left. Then he puts C# on the far right. Going back to the left, Jerry next puts the D, the D# is on the other side, just left of the C#. He's used that method for years..
Marvin M Morgan uses yet another approach:
He puts C in the middle of the receiver. C# is the next pipe to the left of C, Then D is placed to the right of C. So the pattern alternates both sides from the tall C in the center to the shortest pipes of the rank on the ends.
Sometimes one approach is used by these builders is consistent throughout the organ. But sometimes it isn't.
Remember the old Revolutionary War battle scenes where ranks of soldiers would march out onto the battlefield. The first row would kneel down, while the second row fired, then the front rank would rise and fire while the second rank reloaded. The front rank kneels to get out of the way and not "INTERFERE" with the shooting of the soldiers of the second rank.
Sometimes when there are rank after rank of pipes in one area, the pipes are arranged so there slightly larger gaps or areas through which the sounds can travel.
On historic organs, sometimes additions of pipes may be installed by different organ builders. If Bubba B. Organ has died, Marvin M. Morgan may perform the additions. He may copy the arrangement Bubba used. But he may not.
Organists are familiar with these different arrangements of pipes found on individual organs. The difference to the listener may seem slight, but it can be heard. Newer electronic organs now allow the organist to program the arrangement of the pipes by individual ranks. Our sound engine allows this.
Again, probably more than you want to know.
Bach On
P.S. Justaguy has mentioned about 10 or 15 times my statement that I could detect vibrations on the bass speaker at 16 hz by standing in front of it and placing my hand on it. Clearly, he takes this as evidence that the speaker could not adequately produce the 16 hz. "sounds".
Question: can everyone hear sounds below 30 hz. equally?
DrDyna has said, I believe, he can hear sounds well down below 16. Many other people cannot. Maybe I couldn't hear it because I'm one of those people?. Maybe the speaker was doing it, but it was simply outside MY hearing range.
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Thanks to you and others for expanding on the complex issues required to make a successful pipe organ design. I'm fortunate to have a number of various designs within a reasonable driving distance, though the large ones in the Ga. Marble constructed cathedrals are where most of my listening experience is: Atlanta AGO | Georgia Pipe Organ Catalog
FWIW and 'probably 'preaching to choir' here, if you look at a human hearing loudness curve you'll see that we can hear well below 20-30 Hz if it is loud enough, though of course you're right that we all don't hear the same, yet not so much, otherwise there would be just one universal reference speaker system; then if you were to follow my early on recommendation on how to determine the new low speaker's output it would be at the same amplitude as the next higher range existing speaker used for reference, so will be perceived as somewhat lower in amplitude in comparison, though its tactile 'feel' ['rumble' factor] would be greater of course due to the octave lower, exponentially larger, sound wave.
GM
FWIW and 'probably 'preaching to choir' here
, if you look at a human hearing loudness curve you'll see that we can hear well below 20-30 Hz if it is loud enough, though of course you're right that we all don't hear the same, yet not so much, otherwise there would be just one universal reference speaker system; then if you were to follow my early on recommendation on how to determine the new low speaker's output it would be at the same amplitude as the next higher range existing speaker used for reference, so will be perceived as somewhat lower in amplitude in comparison, though its tactile 'feel' ['rumble' factor] would be greater of course due to the octave lower, exponentially larger, sound wave.GM
Why? Speakers are more than capable of playing everything in their frequency range. If we did home stereos like this, with a track, an amp channel and a box for every single voice and instrument no one would have a home stereo. If you want spacious sound, spread speakers around, but they can all play the full range. If it's the acoustic interference you are looking for, I seriously doubt that is a requirement and don't think it's doing what you guys think it's doing.
I'm not trying to make you change your mind, just wondering why you would want to do this the way you are. There's no reason to split different signals to different channels and boxes.
The way that pipes interact when they are 1/4 wave apart or more is interference. At different distances between the sources and different distances between sources and listener the frequency response will be different. That's ALL that's happening.
Well, thanks for confirming that there's many reason to lay out the pipe in various fashions and none of the reasons have anything to do with acoustics. This kind of proves my point that the acoustic interference is not required, not planned and it's more of an oversight than a required sound effect.
Whether or not you can hear 16 hz at all or not is beside the point and I don't want to enter that debate. You should be able to easily perceive it. If you can't perceive it unless you are standing a foot away from the box with your hand on it the audience can't perceive it at all.
The fact that I've had to mention this 10 or 15 times is shocking to me. If you have someone flicking the switch for you and you walk around the church and you can't perceive any difference at all between on and off there's a huge problem.
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