long throw

[widowgobo]

"line arrays offer a 3dB loss at twice distance compared to 6dB from conventional systems"

horn loaded systems are preferable in large halls as they have a much longer throw

[paulears]

... er, and the question is, what?

[Sound In Gloucestershire]

I think hes implying that thomann are silly

[widowgobo]

... er, and the question is, what?

 

 

yeah it was my 3rd time writing out the post every time getting smaller,but is it true I suppose? line arrays having twice the throwing ability.

 

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I think hes implying that thomann are silly

 

 

wel no, but it does look like that, I have heard many I debat regarding this,in my internet travels, and it seems to end in people saying its a myth.

dont think these figures are made up,I was wonerding where they came from?

[Brian]

dont think these figures are made up,I was wonerding where they came from?

 

 

 

Line arrays create a cylindrical wave front in the near field, providing a 3 dB drop off per doubling of distance due to frequencies combining in phase. This is more prominent at high frequencies because they create more interference than low frequencies, due to the shorter wavelengths. But eventually the cylindrical field will transform into a spherical one, this is known as the far field. When the far-field boundary is crossed, the interference has diminished enough for the SPL to decay at the normal 6dB for doubling of distance. This is opposed to the point source which radiates in a spherical waveform which equates to a 6 dBSPL drop.

[Jivemaster]

Usually with a "rock stack" of speakers it's easier to do a reasonable job by eye and ear. With a line array it will usually take a some detailed planning but with that planning (maybe using the proprietry software) the sound can be very good and well distributed and may not have too much spill onto other areas.

 

Either system may suit the job in hand, the skill is making the right choice.

[widowgobo]

dont think these figures are made up,I was wonerding where they came from?

 

 

 

Line arrays create a cylindrical wave front in the near field, providing a 3 dB drop off per doubling of distance due to frequencies combining in phase. This is more prominent at high frequencies because they create more interference than low frequencies, due to the shorter wavelengths. But eventually the cylindrical field will transform into a spherical one, this is known as the far field. When the far-field boundary is crossed, the interference has diminished enough for the SPL to decay at the normal 6dB for doubling of distance. This is opposed to the point source which radiates in a spherical waveform which equates to a 6 dBSPL drop.

 

 

ahh.. thank you

I thought that all speakers had -3dB per doubling.

[Simon Lewis]

A true acoustic line source will propagate with the intensity dropping 3dB per doubling of distance (as long as it remains a line source).

 

Loudspeaker line arrays may approximate to something like a line source, but this is highly dependent upon the length of the array, the degree to which individual elements couple and the frequency that is being reproduced.

 

It could be argued that some loudspeaker arrays achieve better results because they deliberately try to reduce the comb filtering normally inherent in multiple driver systems.

 

"Long Throw" is essentially a misnomer. Directivity and efficiency are better terms to consider when looking at horn loaded loudspeakers.

 

Simon

[widowgobo]

well that makes more sence,but as for the one speaker going ferther than another?

[Simon Lewis]

well that makes more sence,but as for the one speaker going ferther than another?

 

If the sound source is constrained into a smaller solid angle, then the intensity will increase. Think of a hose pipe set to spray in all directions, and then set to squirt in just one. We can argue that there's the same flow of water but that the dispersion's changed.

 

Simon

[Chappie]

Line arrays create a cylindrical wave front in the near field, providing a 3 dB drop off per doubling of distance due to frequencies combining in phase. This is more prominent at high frequencies because they create more interference than low frequencies, due to the shorter wavelengths. But eventually the cylindrical field will transform into a spherical one, this is known as the far field. When the far-field boundary is crossed, the interference has diminished enough for the SPL to decay at the normal 6dB for doubling of distance. This is opposed to the point source which radiates in a spherical waveform which equates to a 6 dBSPL drop.

Different manufacturers have different explanations to what happens exactly, which can be dependant on product, use and marketing. "Can Line Arrays Form Cylindrical Waves?" on Meyer Sound's site is an interesting read and can be found here.

[Rob_Beech]

It's not louder at the back. It's quieter at the front at a given reference point. 1 acoustic watt is exactly that. The sound comes from an 18inch driver or from a very large horn mouth, you measure each and you're measuring a smaller percentage of the source with a horn loaded box thus it appears to "throw the sound". It doesn't. It's no louder at the back unless the cabinet is capable of being louder at source.

[TimmyP1955]

In a properly deployed line array, the farther you are from it, the more of the (very narrow vertical dispersion) boxes you hear, thus the SPL drops off more slowly than with a "point source" box. However if the line is too short, the "line array effect" decreases as the reproduced frequency is decreased. This is (in part) why a proper array has so many boxes. (Additionally, the longer the line, the tighter the pattern control at lower frequencies.)

[Dave SA]

''Line arrays'' bug me. All of the above is the reason why. I've encountered so many badly applied and thought out ''line arrays'' it isn't funny. Keep coming with the science.

[Stan Hope-Streeter]

In a properly deployed line array, the farther you are from it, the more of the (very narrow vertical dispersion) boxes you hear, thus the SPL drops off more slowly than with a "point source" box. However if the line is too short, the "line array effect" decreases as the reproduced frequency is decreased. This is (in part) why a proper array has so many boxes. (Additionally, the longer the line, the tighter the pattern control at lower frequencies.)

 

That may be true of the tweeters in some line array systems, but it is not a correct general explanation for how a line array is meant to work.

 

 

 

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''Line arrays'' bug me. All of the above is the reason why. I've encountered so many badly applied and thought out ''line arrays'' it isn't funny. Keep coming with the science.

 

This is more a reflection on the state of education and competence of the people setting them up, than on the principle itself. *

 

The science is available to anyone who takes the trouble to study basic acoustics.

 

Trouble is, nobody seems to be taught Science any more, and they all think everything can be handed to them on a plate by some computer predictions.

 

* Oh, and on the ethics of modern business, especially as regards marketing, hype, and the God of Immediate Profit.