myth or true>?

[TreyE 10+ year member]

because competing isnt about being heard the furthest away just having the most sound pressure in their car....completely different things....

 

[Big Dee 10+ year member]

great explination thank you now it makes a lot of sense

That isn't even the right explanation. The real reason why bass travels further is because less energy is transfered to air molecules in low notes than in higher notes.

 

[sku 10+ year member]

The frequency is half of the equation. The other half is amplitude or basically how many db's the source is producing.

If I remember correctly...sound loses 3 or 6 dbs for every doubling of distance away from the source...

So essence...to have sound travel really,reall far away...

1) open your hatch

2) play really loud bass

Lastly, the low, low notes are harder to hear as the human ear is less sensitive to the lower octaves (Fletcher Munson)...so your best bet is to play upper/mid bass frequencies really loud instead...

Of course I'm not advocating any of this just trying to explain the mechanics of it...

Feel free to correct any technical mistakes I may have made...

 

[Thnking 10+ year member]

in terms of 30-45 hz when tuning boxes the lower the box is tuned the further the bass will travel?

Sound decays (really transfers energy to heat) in the same fashion for every frequency (given there is no sound absorption, which isn't going to happen). The largest difference in how far sound travels in the real world is energy density. Larger wavelengths have more energy - given the amplitudes are the same. So if someone outputs a single 10khz wavelength and a single 5hz wavelength at the same non-weighted amplitude, the 10khz won't travel as far. But there is nothing saying that a 10khz tone can’t travel as far as a 5hz tone. The amplitudes need to be very different.

 

[ktraughb 10+ year member]

here guys think of this: a fire alarm, a tornado warning siren, a horn on a car, a siren on police cars. all loud *** things that can be heard from far away. do you think those are playing notes below 40 Hz???? i dont think so. maybe that can answer the question a little better. will your car shake more at a low freq? to a certain extent...yes. but, if youre loud outside the car, youre not as loud in. low bass is not loud at distance, just as its not in your car on a termlab meter. the waves are larger, and they will dissipate before a high note. in a nutshell. if anyone with acoustic knowledge sees this, chime in and correct me if im wrong.

 

[sku 10+ year member]

In those examples though...what is the amplitude?

All those examples are all LOUD to begin with.

So maybe the question becomes:

If 2 given frequencies are both equally loud, which 1 will travel further?

Hmm...now I'm wondering...

 

[Big Dee 10+ year member]

the waves are larger, and they will dissipate before a high note. in a nutshell. if anyone with acoustic knowledge sees this, chime in and correct me if im wrong.

You're wrong. See my post a few up.

You just have to look at radio waves as proof, and physics //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

Low frequency radio waves (and sound waves also) always travel further than high frequency waves. ala AM vs FM radio.

Also, your point about police sirens is flawed. The whole point of it is to alarm people and give away the cars location, it would be dumb to use low frequencies because you wouldn't be able to tell where the cop car was. Also it would be impractical to make car horns loud at low notes, you think the car makers are going to spend money to put some subs in a car just to make a louder horn?

Now fog horns, those are things that need to be loud, and they use low frequencies.

 

[Big Dee 10+ year member]

So maybe the question becomes:

If 2 given frequencies are both equally loud, which 1 will travel further?

Hmm...now I'm wondering...

The lower frequency, simple physics.

 

[Big Dee 10+ year member]

One last example before I go to bed.

Ultra low frequency radio is the only frequency that can penetrate below the surface of the ocean floor. Penetration into a medium, that is all that is being discussed here, air molecules are a medium and low frequencies penetrate further.

 

[ktraughb 10+ year member]

You're wrong. See my post a few up.


Now fog horns, those are things that need to be loud, and they use low frequencies.

what do you consider a low frequency? id say those things are a little higher than the average spl burp.

 

[ktraughb 10+ year member]

by the way one more thing. remember this. we dont drive our cars under water. the fact that the sound waves are traveling through a mass of water is highly different than air.

 

[ktraughb 10+ year member]

ok im going to give in now and agree with you. low frequency sound can travel further, mainly from a a car for its reverberation factors in between buildings, houses, through the ground etc. but i would not use the ocean and whales as an example for the fact the moving particles are different in water than they are in the air. the more i read, the more i realize why i was mistaken. if you are outside of a concert, youll often only hear the lower frequencies. but, if you are inside a car on a meter, much different. the higher frequencies will play a louder decibel for a given resonant frequency. i guess if youre just trying to impress people outside your car, go for it real low. but not too low to where it cant even really be heard. i would much rather have a mid-tuned enclosure for the best of both worlds, or just a straight up spl box to show that it can actually get loud, and not just be heard from a half mile away.

 

[T3mpest 10+ year member]

Another things no ones mentioned is diffraction. Low frequency sounds tend to "bend" around objects, whereas higher frequencies will bouce off, this is a LARGE portion of why low frequencies travel so far.

 

[ktraughb 10+ year member]

yup

 

[Big Dee 10+ year member]

ok im going to give in now and agree with you. low frequency sound can travel further, mainly from a a car for its reverberation factors in between buildings, houses, through the ground etc.

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