Bar & Club How Fast Is Arrival Time

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What Would Determine The Fastest Arrival Time?

  • Power Of Speaker (Wattage)

    Votes: 0 0.0%
  • Size 12", 15" etc.

    Votes: 0 0.0%
  • Type/Design

    Votes: 0 0.0%
  • Volume/Loudness

    Votes: 0 0.0%

  • Total voters
    7

ahoustondj

DJ Extraordinaire
Aug 13, 2007
20,235
3,464
Texas
Speaker is at Point A, Listener is at Point B 150 feet away. What determines the fastest arrival time of the sound for that scenario? Vote in Poll!
 
The temperature of the air.
 
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With Steve somewhat, as I would say the atmospheric conditions, at a recent outside gig I went from 90 degrees and 98% humidity at set up and tune, to 91 degrees and 54% humidity at gig time. Temp only changed 1 degree, but the sound went from clear and no bounce backs off the barns and out buildings in the area, to all kinds of acoustic slap back. I had to make major changes in the DSP and minor changes in speaker location and direction. Volume was not changes between the two time lines.

Ray J.
 
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Humidity will have a minor effect as it causes the density of the air to increase, altering the transfer medium slightly.
 
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With Steve somewhat, as I would say the atmospheric conditions, at a recent outside gig I went from 90 degrees and 98% humidity at set up and tune, to 91 degrees and 54% humidity at gig time. Temp only changed 1 degree, but the sound went from clear and no bounce backs off the barns and out buildings in the area, to all kinds of acoustic slap back. I had to make major changes in the DSP and minor changes in speaker location and direction. Volume was not changes between the two time lines.

Ray J.
Ray, the temperature cannot be controlled by the Operator so that is why it is not an option in the Poll. Everything else listed could be changed by the operator. Temperature and the building would be two of the aspects that are to be considered as permanent fixtures which for this will remain constant. In this exercise we will dwell on what and when the listener in point B hears and if that can be changed at will by replacing other components. Just clarifying.
 
Other than temperature, NONE of the other items affect the speed of the arrival of the signal. The design or a set of electronics along the way may delay the signal going to the transducer, but once the signal is created, it travels at the same speed regardless of power, speaker size, volume or design.
 
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The speed of sound is the speed of sound only the whim of nature (atmospheric pressure, or humidity) or the fluid it is moving through (air is fluid too) will affect it.
 
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The speed of sound is the speed of sound only the whim of nature or the fluid it is moving through (air is fluid too) will affect it.

Yes .. temperature, humidity and also pollutants and such will have some effect, though temperature is the biggest factor unless you are in an area where one wouldn't set up a PA system to begin with (polar ice cap, atop a volcano, etc.).

The poll options do not affect the speed of the sound, so the only option that remotely can affect arrival time is design, since it is possible with a DSP or certain crossover components to delay the wave creation and it is possible with say a horn to manually delay it by the horn length.
 
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Ahhh...a question involving actual rocket science. Steve has nailed it. The speed of sound in a fluid (once that fluid is specified) is a function only of temperature. Changing the humidity changes the fluid...and is a consideration for "air" (at least the unconditioned kind). Everything else (well density and pressure are about the only other "interesting" things) are functions only of temperature (and humidity...if you are changing the fluid), and are related through the "perfect gas law." This seems to freak a LOT of people (including first and second year engineering students) out when they first encounter this.

With DRY air, the speed of sound is about 1130ft/sec (or 345m/s) at "room temperature." Using those numbers in really *any* back of the envelope audio calculations will be more than close enough. If you have some kind of finite element computational fluid dynamics code you are running...then you should already know how to figure out the speed of sound.

Outdoors, wind and air currents can/do have an effect on the sound field. An empty stadium and the same place with 50,000 warm water bags putting off a couple hundred BTUs an hour are VERY different places for sound to propagate.

With 150ft of distance between the source and the listener, I would go for "pattern control" as being the largest factor that can be easily influenced by the PA provider.

http://en.wikipedia.org/wiki/Speed_of_sound
 
If there are speakers deployed on the same plane and some may require Delays because of design eg. Folded Horns etc, then adversely we could say that some sound from said speakers do really travel from their point faster than the others on the same plane. That is why we needed the delays for those ones. (NOt referring to speakers deployed in other areas) To the average listener it will be negligent and may not be perceived. So theoretically a certain Horn design or the like can contribute to the sound being transmitted immediately at its exit point or may take awhile through the chambers before it does. All in all it may be hardly noticeable to the untrained ears but a precise measuring device may very well pick up on that difference.
I have also heard that spl may have something to do with the way sound travels. For example, if you have a note being played from a 18" speaker powered in full by a 800 watt amplifier at full blast, then it is possible that the note may be perceived faster than the same note being played from a 20 w 10" speaker and amp. Given that the listener or measuring tool is standing in the same spot. It could be artificial perception, who knows.
 
If there are speakers deployed on the same plane and some may require Delays because of design eg. Folded Horns etc, then adversely we could say that some sound from said speakers do really travel from their point faster than the others on the same plane. That is why we needed the delays for those ones. (NOt referring to speakers deployed in other areas) To the average listener it will be negligent and may not be perceived. So theoretically a certain Horn design or the like can contribute to the sound being transmitted immediately at its exit point or may take awhile through the chambers before it does. All in all it may be hardly noticeable to the untrained ears but a precise measuring device may very well pick up on that difference.
I have also heard that spl may have something to do with the way sound travels. For example, if you have a note being played from a 18" speaker powered in full by a 800 watt amplifier at full blast, then it is possible that the note may be perceived faster than the same note being played from a 20 w 10" speaker and amp. Given that the listener or measuring tool is standing in the same spot. It could be artificial perception, who knows.

To clarify, SPL has no effect on the speed that sound travel at. There may certainly be a "perception" effect if one sound can be heard and another not so easily due to SPL.

Additionallyy, a folded horn does not affect the speed of the sound, only the distance (or time to receive). The speed is still the same.
 
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Look atmosphere, humidity etc.... Play a very minuscule role in how fast sound travels. There are two major factors in line of sight sound travel.... 1. Frequency and 2 amplitude

that said...

High frequencies will travel faster and are more dependent on amplitude for how far they travel before dissipation becomes a factor.

Low frequencies travel slower due to their wave length, but amplitude isn't as big of a factor because dissipation over distance isn't as pronounced as it is for high frequencies. This is also due to the size of the wave length.
 
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Look atmosphere, humidity etc.... Play a very minuscule role in how fast sound travels. There are two major factors in line of sight sound travel.... 1. Frequency and 2 amplitude

that said...

High frequencies will travel faster and are more dependent on amplitude for how far they travel before dissipation becomes a factor.

Low frequencies travel slower due to their wave length, but amplitude isn't as big of a factor because dissipation over distance isn't as pronounced as it is for high frequencies. This is also due to the size of the wave length.

One might think so, but, UM .. NO ... frequency and amplitude have ZERO effect on the speed that sound travels. It's the medium it travels through and the temperature ONLY, as they determine how the pressure wave propagates.


For a physics lesson, see: http://www.physicsclassroom.com/class/sound/u11l2c.cfm

An extract:

The speed of a sound wave in air depends upon the properties of the air, mostly the temperature, and to a lesser degree, the humidity. Humidity is the result of water vapor being present in air. Like any liquid, water has a tendency to evaporate. As it does, particles of gaseous water become mixed in the air. This additional matter will affect the mass density of the air (an inertial property). The temperature will affect the strength of the particle interactions (an elastic property). At normal atmospheric pressure, the temperature dependence of the speed of a sound wave through dry air is approximated by the following equation: v = 331 m/s + (0.6 m/s/C)•T

where T is the temperature of the air in degrees Celsius. Using this equation to determine the speed of a sound wave in air at a temperature of 20 degrees Celsius yields the following solution.


 
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UM .. NO ... frequency and amplitude have ZERO effect on the speed that sound travels. It's the medium it travels through and the temperature ONLY, as they determine how the pressure wave propagates.


For a physics lesson, see: http://www.physicsclassroom.com/class/sound/u11l2c.cfm

So if I whisper your name from 100 yards you'll hear it just as quickly as if I SHOUT your name?

Frequency and amplitude most certainly play a major role.

in water temp, salinity level and water density all play a roll in how far not how fast sound will travel same as in open air... But frequency determines how fast and amplitude determines how far... Atmosphere just determines the level of dissipation over distance occurs
.

The question as I understood it does not account for atmosphere and in any case atmospheric conditions have a lesser affect over speed and the ability to reach its target than frequency and amplitude do. That's not to say that atmosphere has no affect just that it plays a minor role in comparison.

yes the article is correct in more technical terms but, what I state is in simplistic terms most here will understand easier.

there are a lot of factors not discussed in the article that also factor into speed of sound such as reflections and refraction off of surfaces in the path of sound. Again this was not part of the original question.

Trust me, the government did.
 
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You're telling a sonar operator this?

in water temp, salinity level and water density all play a roll in how far not how fast sound will travel same as in open air... But frequency determines how fast and amplitude determines how far... Atmosphere just determines the level of dissipation over distance occurs
.

The question as I understood it does not account for atmosphere and in any case atmospheric conditions have a lesser affect over speed and the ability to reach its target than frequency and amplitude do. That's not to say that atmosphere has no affect just that it plays a minor role in comparison.

Trust me, the government did.

Sonar waves are the same from a physics perspective, though the medium is different and therefore the speed will be different than through air, and the water density, salinity levels and such will have an effect on the makeup of the water, so they will change the speed to a minor level.

Amplitude does indeed determine how far a wave will travel, but not the speed of it.

Frequency does not determine how fast it will travel.
 
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Looking for references of frequency effect on sound speed, there appears to be some very minor effect due to some molecular compression in certain non standard mediums, but haven't found anything other than some theoretical verbiage. Will keep looking.


** update ** no luck other than references to "some minimal effect" by amplitude and frequency both causing some type of micro compression which affects the propagation speed similar to air/water pressure changes, though at a much more minimal scale.
 
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Sonar waves are the same from a physics perspective, though the medium is different and therefore the speed will be different than through air, and the water density, salinity levels and such will have an effect on the makeup of the water, so they will change the speed to a minor level.

Amplitude does indeed determine how far a wave will travel, but not the speed of it.

Frequency does not determine how fast it will travel.

how can you say frequency does not factor in? It most certainly does.... Your article is incorrect in its stipulation in the relationship to frequency and speed... The higher the frequency the faster it disrupts the medium it travels on or through.

I never said amplitude affects speed. As you said it only affects distance and that I agree with.

from a submarines perspective it's easier to hide in a hot water pocket then cold because sound under water travels better in cold water than warm water due to density and selenite content. But we're not talking about water.

do this play a sample frequency at a 100hz and then one at 1khz from 100 feet with all factors being equal other than frequency which one reaches the target first?

now increase the amplitude of each and tell me if they reached you faster.

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This shows the direct relationship between frequency and speed

http://www.gcse.com/waves/wave_speed2.htm
 
how can you say frequency does not factor in? It most certainly does.... Your article is incorrect in its stipulation in the relationship to frequency and speed... The higher the frequency the faster it disrupts the medium it travels on or through.

I never said amplitude affects speed. As you said it only affects distance and that I agree with.

from a submarines perspective it's easier to hide in a hot water pocket then cold because sound under water travels better in cold water than warm water due to density and selenite content. But we're not talking about water.

do this play a sample frequency at a 100hz and then one at 1khz from 100 feet with all factors being equal other than frequency which one reaches the target first?

now increase the amplitude of each and tell me if they reached you faster.


Sorry Joker, if you play a 100Hz, a 1KHz, and a 10KHz sound at 100 feet .. all three will arrive at the exact same time .. it's physics. They may not be at the same amplitude due to the drivers, horn type, etc., but they will in fact arrive at the same time. I will bet any amount you'd like on that.

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This shows the direct relationship between frequency and speed

http://www.gcse.com/waves/wave_speed2.htm

That's not a "direct" relationship, it is an indirect relationship, as there are 2 parameters that would change on the left side of the equation : the frequency (wavelength) AND the time period, which varies with the frequency, so the "speed" will be the same.
 
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Sorry Joker, if you play a 100Hz, a 1KHz, and a 10KHz sound at 100 feet .. all three will arrive at the exact same time .. it's physics. They may not be at the same amplitude due to the drivers, horn type, etc., but they will in fact arrive at the same time. I will bet any amount you'd like on that.

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That's not a "direct" relationship, it is an indirect relationship, as there are 2 parameters that would change on the left side of the equation : the frequency (wavelength) AND the time period, which varies with the frequency, so the "speed" will be the same.
Sorry I did misspeak what I was trying to correlate, which the article I linked above does better, is that frequency of a sound wave do factor.
 
Sorry I did misspeak what I was trying to correlate, which the article I linked above does better, is that frequency of a sound wave do factor.

The frequency does affect the wavelength, just not the speed of propagation.

I think some of the problem is that in the real world, what we hear is affected by a number of parameters, including the design of the speakers, but thankfully, some, like the speed of sound, are pretty much fixed .. ain't science great. :)
 
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