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Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => LAB: The Classic Live Audio Board => Topic started by: Nick Tims on April 27, 2024, 07:03:40 AM
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Hello, I would like to make a configuration on the stage, namely: 4 speakers with 2 subwoofers will be on the stage and 4 subwoofers in the middle of the stage, I will have to add delay, but what do you think it will sound ok? Is it okay to place it like this?
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Hello, I would like to make a configuration on the stage, namely: 4 speakers with 2 subwoofers will be on the stage and 4 subwoofers in the middle of the stage, I will have to add delay, but what do you think it will sound ok? Is it okay to place it like this?
What is the purpose of placing them in this configuration? Have you modeled the coverage yet? I don’t see the purpose of the subs up on the stage having the line in front of the stage if properly delayed in an end fire configuration, can be steered to achieve certain coverage goals.
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What is the purpose of placing them in this configuration? Have you modeled the coverage yet? I don’t see the purpose of the subs up on the stage having the line in front of the stage if properly delayed in an end fire configuration, can be steered to achieve certain coverage goals.
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Because the tops will sit on the rod directly in them that's why I want to do this.
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Because the tops will sit on the rod directly in them that's why I want to do this.
If you are just using the subs on stage as a stand it will probably sound better if the stage subs are turned off.
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If you are just using the subs on stage as a stand it will probably sound better if the stage subs are turned off.
My thoughts exactly a last time I checked speaker stands are cheaper than subs.
If appearance is an issue a couple of sticks of truss, baseplates and top plates plus a couple of truss warmers (triangular LED lights that fit inside the truss) give a very sophisticated look.
To the OP are you delaying this subs individually?
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Hello, I would like to make a configuration on the stage, namely: 4 speakers with 2 subwoofers will be on the stage and 4 subwoofers in the middle of the stage, I will have to add delay, but what do you think it will sound ok? Is it okay to place it like this?
What speakers are you going to delay and why? What are you trying to accomplish?
Delay can both help and hurt at the same time, it depends on what is most important.
Do you understand what different delays on different speaker can do? Do you have the tools and knowledge to properly measure the results?
Delays for subs and delays for tops to subs are done for different reasons.
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What speakers are you going to delay and why? What are you trying to accomplish?
Delay can both help and hurt at the same time, it depends on what is most important.
Do you understand what different delays on different speaker can do? Do you have the tools and knowledge to properly measure the results?
Delays for subs and delays for tops to subs are done for different reasons.
That was why I suggested to get some stands or truss segments for stage. That would be a complicated array. I don't think the OP knows about controlling pattern with delay because he hasnt responded to my questions in any detail.
Merlijn free spreadsheet is a great way to play with different configs.
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That was why I suggested to get some stands or truss segments for stage. That would be a complicated array. I don't think the OP knows about controlling pattern with delay because he hasnt responded to my questions in any detail.
Agreed; this is no longer a simple 2D issue, but 3D. Not only that, but ground bounce from the subs on the stage is another negative variable into the mix that will change based on distances to various surfaces.
Since the subs on the stage are merely expensive speaker stands - do like others have suggested and invest in some type of stands (tripod or truss), put the subs on the floor, space no more than 6' apart center to center, and use a delay calc to set per-sub delay times.
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Good advice above. If you are mixing ((by this meaning using) different brands of subwoofers together, without measuring equipment to determine phase relationships between the brands, you are asking for trouble. At one time (for a long time) a positive voltage in a JBL sub caused the cone to move inward when with almost every other brand sub, a positive voltage caused the cone to move outward. With two subs side by side, the bass would be mostly canceled due to the 180-degree phase differences. It is even more complicated now due to the digital processing in most active subwoofers. Phase relationship can vary greatly with frequency causing strong comb filtering when mixing brands. More subs isn't always better.
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That was an idea, and yes I can measure distances, nothing is active, everything is passive, subwoofers are Void Stasys all. The array tops are made by me , but I was curious if anyone had tried this placement.
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That was an idea, and yes I can measure distances, nothing is active, everything is passive, subwoofers are Void Stasys all. The array tops are made by me , but I was curious if anyone had tried this placement.
Being passive doesn't bring anything to the table, nor does all being the same. Home built tops I will reserve judgment on but it's hard to be an acoustic engineer and structural by yourself, then tune the boxes and produce something better than the usual suspects.
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I'm going to guess this if for a DJ gig so low-frequency directivity is probably not the highest priority, in which case, I'd say just make a pile with your four subs in the middle (2 over 2). This will give you the most even coverage across the space and eliminate the need for multiple channels of DSP to do a virtual arc delay.
If your other two subs that were being used as risers for your mains are also the same model, then go ahead and throw them in the pile (3 stacks of 2, all touching and in the center) and use something else on stage to get your mains up in the air (stands, scaffolding, stage decks, whatever).
You'll get a lot of LF spill back on to the stage but in my experience that's typically a positive thing for modern DJs (not so good for old-school vinyl setups).
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At one time (for a long time) a positive voltage in a JBL sub caused the cone to move inward when with almost every other brand sub, a positive voltage caused the cone to move outward. With two subs side by side, the bass would be mostly canceled due to the 180-degree phase differences.
I learned that the hard way.
Many moons and decades ago, at my first "big gig" I brought out my whole system. The subs were 4 W bins that half were EV and half were JBL loaded.
When I fired it up there was almost no bass, so I turned it up. After a little bit I had no subs, they were all blown.
THe guy doing the lighting (who also had his own sound company) help me swap drivers (I had brought some spares just in case) and he said "did you know your JBL speakers were wired up backwards?" I said they were wired up correctly (thinking that red meant positive).
He said "when you get them reconed, check the polarity with a battery".
That was an expensive lesson, but it put me on a better path.
Oh what I have learned since those days------------
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Being passive doesn't bring anything to the table, nor does all being the same. Home built tops I will reserve judgment on but it's hard to be an acoustic engineer and structural by yourself, then tune the boxes and produce something better than the usual suspects.
I havWhy do you find it impossible to make line array systems I often see people who comment that it doesn't sound like it doesn't work, before array I used and built various enclosures, I never failed with them, I have over 300 live festivals, only now I started working with line array and studied them, Special horn deflections etc After all, the line array is not so special compared to classic systems, but you have to have a lot to make the array to be at 100 Hz. So they won't sound unless you put something weak in them and the construction is bad.
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I havWhy do you find it impossible to make line array systems I often see people who comment that it doesn't sound like it doesn't work, before array I used and built various enclosures, I never failed with them, I have over 300 live festivals, only now I started working with line array and studied them, Special horn deflections etc After all, the line array is not so special compared to classic systems, but you have to have a lot to make the array to be at 100 Hz. So they won't sound unless you put something weak in them and the construction is bad.
Stacking two speakers, as shown in your drawing, does not make a line array.
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Stacking two speakers, as shown in your drawing, does not make a line array.
Line? 2 boxes doesn't even make hyphen or a dash, let alone a line array.
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Who said that? I said tops are array And yes you need minimum 4 pieces, but how jbl vrx or l acoustics kiva They sell systems like that and nobody complains about the sound. Especially even 2 charts throw more than point source, comparison made with ev Eliminator, Qsc, Jbl, RCF NX etc
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Who said that? I said tops are array And yes you need minimum 4 pieces, but how jbl vrx or l acoustics kiva They sell systems like that and nobody complains about the sound. Especially even 2 charts throw more than point source, comparison made with ev Eliminator, Qsc, Jbl, RCF NX etc
You really dont know much about pa do you? You need to do a lot of study, and then maybe come back.
Or hopefully your study will give you the answers you need. Several people here have given you good answers, but no, you dont listen and learn.
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Especially even 2 charts throw more than point source, comparison made with ev Eliminator, Qsc, Jbl, RCF NX etc
I assume this is a typo-or else I don't understand what you are trying to say.
But multiple boxes will not "throw" (in the classical sense of intelligibility/clarity at a distance) as well as a single box (assuming they both start out at the same level) because of the interference that happens with more than one device covering the same area, ie comb filtering.
The interference of multiple boxes is what causes the sound to fall apart at a distance, NOT add together or "throw" better.
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For example, Martin Audio W8VDQ combines line array and differential dispersion technologies to provide an advanced solution to the requirement of even coverage over wide angles and throw distances. Short throw horizontal dispersion is 120º, narrowing to 100º as throw increases. Let's see what you have to say, there is also QSC KLA, L Acoustics Kiva, Jbl VRX etc
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For example, Martin Audio W8VDQ combines line array and differential dispersion technologies to provide an advanced solution to the requirement of even coverage over wide angles and throw distances. Short throw horizontal dispersion is 120º, narrowing to 100º as throw increases. Let's see what you have to say, there is also QSC KLA, L Acoustics Kiva, Jbl VRX etc
This sounded like marketing material copy/pasted. If so, it should be taken with a large measure of salt.
You have access to some really seasoned and well-educated pros on this forum, but your tone is coming across (to me, at least) as challenging and dismissive of their expertise. If you actually want to learn, you have to be open…genuinely open… to the possibility that your preconceptions are wrong. If you don’t want to learn, then you probably don’t need to ask questions here.
PS - sincere thanks to the many professionals here who share their hard-won knowledge with people like me who know just enough to be dangerous and are liable to fall into the Dunning-Kruger trap.
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I mean I get a lot of spl with 4 tops having a total of 8 HF drivers than the point source, I do rock and metal concerts and outdoors even compact as it sounds very good. Even the sound engineers who come up with those bands are happy with the sound.
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Let's see what you have to say, there is also QSC KLA, L Acoustics Kiva, Jbl VRX etc
KLA and VRX are NOT a line array, and they both suck, badly. Yes I have heard and deployed them personally. Trying to prove your endeavors are better than the worst wanna-be "line array" doesn't instill any confidence. Kiva/Kilo I've used (our company designed, installed, and tuned a system), it's a line array at some frequencies, but it's not like the other two.
Threads like these simply prove why trusting someone's DIY project speakers is a bad idea.
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KLA and VRX are NOT a line array, and they both suck, badly. Yes I have heard and deployed them personally. Trying to prove your endeavors are better than the worst wanna-be "line array" doesn't instill any confidence. Kiva/Kilo I've used (our company designed, installed, and tuned a system), it's a line array at some frequencies, but it's not like the other two.
Threads like these simply prove why trusting someone's DIY project speakers is a bad idea.
And worse, believing the bullshit. Nick has been placed in my Iggy Bin.
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KLA and VRX are NOT a line array, and they both suck, badly. Yes I have heard and deployed them personally. Trying to prove your endeavors are better than the worst wanna-be "line array" doesn't instill any confidence. Kiva/Kilo I've used (our company designed, installed, and tuned a system), it's a line array at some frequencies, but it's not like the other two.
Threads like these simply prove why trusting someone's DIY project speakers is a bad idea.
I'm curious what sound systems sound good if they don't. I listened to line array L Acoustics V Dosc. Kara, Jbl VTX, Funktion One, Adamson, RCF HDL, TT, Alcons That it's an aspect doesn't interest me, but that you do your job with them and you hear it clearly. What do you find impossible to achieve a sound system?
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For example, Martin Audio W8VDQ combines line array and differential dispersion technologies to provide an advanced solution to the requirement of even coverage over wide angles and throw distances. Short throw horizontal dispersion is 120º, narrowing to 100º as throw increases. Let's see what you have to say, there is also QSC KLA, L Acoustics Kiva, Jbl VRX etc
It is very simple. When you have more than one box covering the same area, you WILL have interference (I don't care what the marketing dept says).
That interference is called combfiltering, and varies with freq based on the different arrival time of the different boxes.
That is what affects "the throw". The more boxes you have, the more interference (now at more freq) you have.
That is the physics, and the marketing dept can't get around it, no matter what they say.
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I mean I get a lot of spl with 4 tops having a total of 8 HF drivers than the point source, I do rock and metal concerts and outdoors even compact as it sounds very good. Even the sound engineers who come up with those bands are happy with the sound.
Yes, more drivers can produce more SPL, all thing else being equal.
However unless the drivers are designed to work together (and multiple boxes of the same model are NOT going to sum together as well as a single source that is designed to).
I'm glad the guests are happy, but that does not change the science and the problems. You have to remember that MOST people are use to hearing interference, and they think it is "correct", simply because they don't have a good reference.
When you take a "proper point source" and one limiting point (it could be price, or size, or weight etc) the multibox solution is generally going to lose in either SPL or sound quality.
But if you are simply comparing 1 box to a pile of other boxes, and SPL is the only thing that matters, you will come up with different results. But that is not a fair comparison. Something has to be equal to even begin to compare.
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That's what I wanted to say that I need spl and it helps me a lot, I didn't want to attack anyone but the discussion was different.
https://files.fm/u/s8tm5qkdu8 A demo as an idea what this system made by me sounds like. I amplify them with Gruppen Lab old Lab series.
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It is very simple. When you have more than one box covering the same area, you WILL have interference (I don't care what the marketing dept says).
That interference is called combfiltering, and varies with freq based on the different arrival time of the different boxes.
That is what affects "the throw". The more boxes you have, the more interference (now at more freq) you have.
That is the physics, and the marketing dept can't get around it, no matter what they say.
For those of us who really are here to learn, I'd like to understand a bit more about this. I realize that physics would dictate the best possible source would be a single point, but physical driver limitations* mean that you can only displace so much air per given driver. So speaker systems end up being built with multiple drivers, often covering the same frequencies. Am I wrong in assuming that when you say "When you have more than one box covering the same area, you WILL have interference," this principle also applies to multiple drivers within the same box?
An example is what I have: the DB Technologies IG4T. 4 drivers deliver the low-mid frequencies. When they are stacked, they stack so that the horns are closest together.
So (overly simplistically), although there is some destructive interference, it is taken advantage of in a way that helps create a more controlled, cylindrical dispersion pattern? And that you can make it so the inverse-square law is tricked a bit by the vertical spread of the drivers?
*barring the use of a horn to combine multiple drivers
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For those of us who really are here to learn, I'd like to understand a bit more about this. I realize that physics would dictate the best possible source would be a single point, but physical driver limitations* mean that you can only displace so much air per given driver. So speaker systems end up being built with multiple drivers, often covering the same frequencies. Am I wrong in assuming that when you say "When you have more than one box covering the same area, you WILL have interference," this principle also applies to multiple drivers within the same box?
An example is what I have: the DB Technologies IG4T. 4 drivers deliver the low-mid frequencies. When they are stacked, they stack so that the horns are closest together.
So (overly simplistically), although there is some destructive interference, it is taken advantage of in a way that helps create a more controlled, cylindrical dispersion pattern? And that you can make it so the inverse-square law is tricked a bit by the vertical spread of the drivers?
*barring the use of a horn to combine multiple drivers
Destructive interference occurs when the drivers are not located within 1/2 wavelength (of lowest frequency) of each other. Easy to achieve with subs. 100Hz is 12 feet! It is very difficult at high frequencies, needs specially constructed waveguides that reach to the extent of the enclosure to form a single waveguide. Not going to get that in a prosumer product.
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"When you have more than one box covering the same area, you WILL have interference," this principle also applies to multiple drivers within the same box?
An example is what I have: the DB Technologies IG4T. 4 drivers deliver the low-mid frequencies. When they are stacked, they stack so that the horns are closest together.
So (overly simplistically), although there is some destructive interference, it is taken advantage of in a way that helps create a more controlled, cylindrical dispersion pattern? And that you can make it so the inverse-square law is tricked a bit by the vertical spread of the drivers?
*barring the use of a horn to combine multiple drivers
Interference from the same box is dependent on frequency, driver spacing, the listener's angle off axis and distance.
The simplistic line array "wedge of cheese" cylindrical dispersion pattern and 3dB drop per doubling of distance only applies to the destructive interference in the near field, which varies with frequency.
The DB Technologies IG4T uses a vertically asymmetric high frequency horn above 1100 Hz. The horn's coverage area is directed slightly downward.
When two IG4T are stacked horn to horn, their -6dB coverage pattern results in ~ 0dB on axis constructive interference above ~ 1100 Hz.
For a stacked pair of IGT4, (75.28 inches tall, just under 2 meters) you are out of the near field on-axis destructive interference zone at ~5.5 feet (1.68 meters) at 100 Hz, and ~60 feet (18.5 meters) at 1100 Hz, using 1130 feet (344.2 meters) per second as the speed of sound (at 72 degrees Fahrenheit, 21.7 Celsius).
If it's hotter, the near field is closer, colder is further.
From:
https://www.prosoundtraining.com/2010/03/17/line-array-limitations/
The near field distance can be defined by the following relationship:
D=1.57 L squared/λ
where
D is the distance to the far field transition
L is the physical length of the line source
λ = the wavelength of the frequency in question (all lengths in identical units).
Beyond this distance the listener is in the far field and there is 6 dB drop in level per doubling of distance. The transition distance can be quite long at short wavelengths, that is, high frequencies, but it is shorter at low frequencies. For each octave lower in frequency, the transition distance is cut in half.
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