Tweeter location, where and why?
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07-22-2004, 01:10 AM
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#17
07-22-2004, 09:02 AM
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Re: Key to good imaging.
Originally posted by StruckBy99
The trick to imaging is to get the speakers an equal distance apart from your ears. If the left is only 20" away from your ears and the right is 40", your going to hear the left one first and it going to pull the soundstage to the left. It has nothing to do with volume, its all timing. You need to find a spot to mount the speakers that is closest to an equal distance apart from the drivers listening position.
The trick to imaging is to get the speakers an equal distance apart from your ears. If the left is only 20" away from your ears and the right is 40", your going to hear the left one first and it going to pull the soundstage to the left. It has nothing to do with volume, its all timing. You need to find a spot to mount the speakers that is closest to an equal distance apart from the drivers listening position.
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07-22-2004, 11:17 AM
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DO NOT POINT THEM AT HTE WINDSHIELD
a tweeter handles very high frequency and thus the wave length is very very tight.
Remember that the human ear can hear to about 20,000 hz. anything above that is making dogs howl. Many tweeters are advertised of going to 50k or higher. NO need for them!
Now bouncing a tweeter frequency off a hard object (such as a windshield) shatters the wave length. While it may sound like the tweeter has more presence, the overall quality is GREATLY DIMINISHED. and I'll argue with anyone regarding that point!
As a former car audio installer and former part owner of a high end car audio shop, I know what I'm talking about. Whereas, that was about 10 years ago, sound wave lengths never change.
Example.
Picture a heart monitoring machine. it has a steady pace, up and down.
That is what a wave length would look like for a low signal (bass)
now a tweeter one is very close together, up and down, righ tnext to each other.
by bouncing that off a windshield you shatter that wave length. A los wave length (bass) doesn't shatter becuase you have to be a 1/4 wave length away to hear it. That is why with low bass, you fel it, but to actually hear it you ahve to go stand 15' in front of your truck. Becuase that is where a 1/4 wave length would be.
Lastly,
How any pro-cars on the audo circuit bounce tweeters off a windshiled. ANSWER --> NONE!
there is a reason for it.
do not bounce it off the windshield, if you are going to do so, you may as well buy a $10 set of tweeters becuase you don't car about quality.
a tweeter handles very high frequency and thus the wave length is very very tight.
Remember that the human ear can hear to about 20,000 hz. anything above that is making dogs howl. Many tweeters are advertised of going to 50k or higher. NO need for them!
Now bouncing a tweeter frequency off a hard object (such as a windshield) shatters the wave length. While it may sound like the tweeter has more presence, the overall quality is GREATLY DIMINISHED. and I'll argue with anyone regarding that point!
As a former car audio installer and former part owner of a high end car audio shop, I know what I'm talking about. Whereas, that was about 10 years ago, sound wave lengths never change.
Example.
Picture a heart monitoring machine. it has a steady pace, up and down.
That is what a wave length would look like for a low signal (bass)
now a tweeter one is very close together, up and down, righ tnext to each other.
by bouncing that off a windshield you shatter that wave length. A los wave length (bass) doesn't shatter becuase you have to be a 1/4 wave length away to hear it. That is why with low bass, you fel it, but to actually hear it you ahve to go stand 15' in front of your truck. Becuase that is where a 1/4 wave length would be.
Lastly,
How any pro-cars on the audo circuit bounce tweeters off a windshiled. ANSWER --> NONE!
there is a reason for it.
do not bounce it off the windshield, if you are going to do so, you may as well buy a $10 set of tweeters becuase you don't car about quality.
Last edited by l-menace; 07-22-2004 at 11:26 AM.
#20
07-22-2004, 12:05 PM
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Re: Key to good imaging.
Exactly what I have done with my truck. I run MB Quart speakers, the tweeters are 3.5" from the midranges in the doors, and my Alpine DSP does time-correction for my listening position.
Creates a great sound.
Daniel
Creates a great sound.
Daniel
Originally posted by StruckBy99
The trick to imaging is to get the speakers an equal distance apart from your ears. If the left is only 20" away from your ears and the right is 40", your going to hear the left one first and it going to pull the soundstage to the left. It has nothing to do with volume, its all timing. You need to find a spot to mount the speakers that is closest to an equal distance apart from the drivers listening position.
Measure the distance from the left door speaker, then mesure the distance to the right one. Its damn near twice as far away. When you turn on your stereo, close your eyes and try to picture where the voices are coming from. In a perfect imaging vehicle, they should seem to come right from the middle of the windshield. With the stock speaker placement, it'll be hard to find a definate spot where the voices are coming from but they will tend mostly to come from the left because the speaker is closer.
This is the reason why kick panels work so well. Your placing the speakers closer to an equal distance apart. Get out your tape measure and you'll see what I'm talking about. If you can get the speakers less than a difference of 8", you'll notice the "image" move closer toward the center of the windshield.
Tweeters are VERY directional. Aiming tweeters toward the center of the vehicle also helps with imaging, but there is alot of trial and error. Lower frequencies are not AS directional, especially the sub-bass frequencies which are OMNI-directional. Meaning placement doesnot matter as much due to the fact the sound waves move so slowly.
Another good thing to note:
To get the best sound from component speakers, mount the tweeter close to the mid range. The rule here is to mount them no further apart than the crossover dictates. For example: if the crossover point is 3500hz try to mount them no further than 3.5" apart. If its 4000hz, no more than 4" apart. The purpose is to keep from hearing where one speaker stops playing and the other one starts.
Ultimately your ear is the judge!!!!
Sorry for the lengthy relpy.
I hope all this helps
Jason
The trick to imaging is to get the speakers an equal distance apart from your ears. If the left is only 20" away from your ears and the right is 40", your going to hear the left one first and it going to pull the soundstage to the left. It has nothing to do with volume, its all timing. You need to find a spot to mount the speakers that is closest to an equal distance apart from the drivers listening position.
Measure the distance from the left door speaker, then mesure the distance to the right one. Its damn near twice as far away. When you turn on your stereo, close your eyes and try to picture where the voices are coming from. In a perfect imaging vehicle, they should seem to come right from the middle of the windshield. With the stock speaker placement, it'll be hard to find a definate spot where the voices are coming from but they will tend mostly to come from the left because the speaker is closer.
This is the reason why kick panels work so well. Your placing the speakers closer to an equal distance apart. Get out your tape measure and you'll see what I'm talking about. If you can get the speakers less than a difference of 8", you'll notice the "image" move closer toward the center of the windshield.
Tweeters are VERY directional. Aiming tweeters toward the center of the vehicle also helps with imaging, but there is alot of trial and error. Lower frequencies are not AS directional, especially the sub-bass frequencies which are OMNI-directional. Meaning placement doesnot matter as much due to the fact the sound waves move so slowly.
Another good thing to note:
To get the best sound from component speakers, mount the tweeter close to the mid range. The rule here is to mount them no further apart than the crossover dictates. For example: if the crossover point is 3500hz try to mount them no further than 3.5" apart. If its 4000hz, no more than 4" apart. The purpose is to keep from hearing where one speaker stops playing and the other one starts.
Ultimately your ear is the judge!!!!
Sorry for the lengthy relpy.
I hope all this helps
Jason
#22
07-22-2004, 12:39 PM
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Originally posted by l-menace
DO NOT POINT THEM AT HTE WINDSHIELD
. . . Now bouncing a tweeter frequency off a hard object (such as a windshield) shatters the wave length.
. . . As a former car audio installer and former part owner of a high end car audio shop, I know what I'm talking about. Whereas, that was about 10 years ago, sound wave lengths never change.
. . . by bouncing that off a windshield you shatter that wave length. A los wave length (bass) doesn't shatter becuase you have to be a 1/4 wave length away to hear it. That is why with low bass, you fel it, but to actually hear it you have to go stand 15' in front of your truck. Becuase that is where a 1/4 wave length would be. . .
DO NOT POINT THEM AT HTE WINDSHIELD
. . . Now bouncing a tweeter frequency off a hard object (such as a windshield) shatters the wave length.
. . . As a former car audio installer and former part owner of a high end car audio shop, I know what I'm talking about. Whereas, that was about 10 years ago, sound wave lengths never change.
. . . by bouncing that off a windshield you shatter that wave length. A los wave length (bass) doesn't shatter becuase you have to be a 1/4 wave length away to hear it. That is why with low bass, you fel it, but to actually hear it you have to go stand 15' in front of your truck. Becuase that is where a 1/4 wave length would be. . .
While I do not disagree that bouncing is a bad idea (depends on the installation--Bose made a whole company out of reflected sound), the wavelength of the sound simply does not change, whether bounced off of glass or a marshmallow. Certain materials can attenuate the sound at certain frequencies, but they cannot and do not change the wavelength of that sound. A 20 KHz wave will remain 20KHz until dissappated or absorbed, irrespective of how many times that it is bounced.
Same is true for bass. A 20 Hz sound is felt more than heard in a cab because you are in the pressure zone. Moving outside of the vehicle simply takes you out of the pressure zone. The pressure zone is also critical in that you are in the nearfield for standing waves. Standing waves are when a sound bounces off a surface and collides with another wave at the same frequency (which is where the 1/4 wavelength issue arises). That collision produces (at that spot) a very strong response at that frequency. This is why when you walk around a room, the bass gets weaker or stronger depending on where you stand (non-rectangular rooms minimize this phenomenon).
But irrespective of all of this wavelength does not change. Nor is you ear unable to hear a low bass tone because you are too close to the speaker. If a sound in the range of human hearing is felt more, it is also being heard more at the same time. The amplitiude of the wave is the determinant, not the distance from the speaker per se.
The only wavelength change that most people will ever experience is the Doppler effect, which is what causes a train to change tone as it passes by. But the wavelengths emanating from that trian never change, it's just that its movement is additive or subtractive to the wavelengths as heard from your position; standing on the train, the wavelengths stay the same.
See, e.g.,
Acoustics and vibration animations
Acoustic definitions
Last edited by Tim Skelton; 07-22-2004 at 12:43 PM.
#23
07-22-2004, 12:48 PM
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What happens to a wave when it shatters? Do only high frequency waves shatter?
"by bouncing that off a windshield you shatter that wave length. A los wave length (bass) doesn't shatter becuase you have to be a 1/4 wave length away to hear it. That is why with low bass, you fel it, but to actually hear it you ahve to go stand 15' in front of your truck. Becuase that is where a 1/4 wave length would be."
Isn't a 1/4 wavelength the crest or trough of the wave - which gives max volume? and What if the speaker is playing several frequencies at the same time and you are no longer dealing with pure sine waves?
"by bouncing that off a windshield you shatter that wave length. A los wave length (bass) doesn't shatter becuase you have to be a 1/4 wave length away to hear it. That is why with low bass, you fel it, but to actually hear it you ahve to go stand 15' in front of your truck. Becuase that is where a 1/4 wave length would be."
Isn't a 1/4 wavelength the crest or trough of the wave - which gives max volume? and What if the speaker is playing several frequencies at the same time and you are no longer dealing with pure sine waves?
#24
07-22-2004, 01:18 PM
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Originally posted by Tim Skelton
Menace, Menace, Menace. I hope that acoustics is not on the bar exam.
While I do not disagree that bouncing is a bad idea (depends on the installation--Bose made a whole company out of reflected sound), the wavelength of the sound simply does not change, whether bounced off of glass or a marshmallow. Certain materials can attenuate the sound at certain frequencies, but they cannot and do not change the wavelength of that sound. A 20 KHz wave will remain 20KHz until dissappated or absorbed, irrespective of how many times that it is bounced.
Same is true for bass. A 20 Hz sound is felt more than heard in a cab because you are in the pressure zone. Moving outside of the vehicle simply takes you out of the pressure zone. The pressure zone is also critical in that you are in the nearfield for standing waves. Standing waves are when a sound bounces off a surface and collides with another wave at the same frequency (which is where the 1/4 wavelength issue arises). That collision produces (at that spot) a very strong response at that frequency. This is why when you walk around a room, the bass gets weaker or stronger depending on where you stand (non-rectangular rooms minimize this phenomenon).
But irrespective of all of this wavelength does not change. Nor is you ear unable to hear a low bass tone because you are too close to the speaker. If a sound in the range of human hearing is felt more, it is also being heard more at the same time. The amplitiude of the wave is the determinant, not the distance from the speaker per se.
The only wavelength change that most people will ever experience is the Doppler effect, which is what causes a train to change tone as it passes by. But the wavelengths emanating from that trian never change, it's just that its movement is additive or subtractive to the wavelengths as heard from your position; standing on the train, the wavelengths stay the same.
See, e.g.,
Acoustics and vibration animations
Acoustic definitions
Menace, Menace, Menace. I hope that acoustics is not on the bar exam.
While I do not disagree that bouncing is a bad idea (depends on the installation--Bose made a whole company out of reflected sound), the wavelength of the sound simply does not change, whether bounced off of glass or a marshmallow. Certain materials can attenuate the sound at certain frequencies, but they cannot and do not change the wavelength of that sound. A 20 KHz wave will remain 20KHz until dissappated or absorbed, irrespective of how many times that it is bounced.
Same is true for bass. A 20 Hz sound is felt more than heard in a cab because you are in the pressure zone. Moving outside of the vehicle simply takes you out of the pressure zone. The pressure zone is also critical in that you are in the nearfield for standing waves. Standing waves are when a sound bounces off a surface and collides with another wave at the same frequency (which is where the 1/4 wavelength issue arises). That collision produces (at that spot) a very strong response at that frequency. This is why when you walk around a room, the bass gets weaker or stronger depending on where you stand (non-rectangular rooms minimize this phenomenon).
But irrespective of all of this wavelength does not change. Nor is you ear unable to hear a low bass tone because you are too close to the speaker. If a sound in the range of human hearing is felt more, it is also being heard more at the same time. The amplitiude of the wave is the determinant, not the distance from the speaker per se.
The only wavelength change that most people will ever experience is the Doppler effect, which is what causes a train to change tone as it passes by. But the wavelengths emanating from that trian never change, it's just that its movement is additive or subtractive to the wavelengths as heard from your position; standing on the train, the wavelengths stay the same.
See, e.g.,
Acoustics and vibration animations
Acoustic definitions
I think l-menance meant something different then the words he used.
The key to the glass and sound is how it is reflecting. It would be more involved to get the reflection correct then to direct the soundwave at you. The windshield glass will mostly reflect, absorb some and transmit (possible diffracting, based no the glass structure) the waves...this would lead to points where you have similar waves crossing at your "observation" location and may make it sound like crap.
Goes back to square one. Its about location. Move the speakers around until you find the sound spot YOU like, and thats the one to go with.
Time-base correct if you can and you can get positional sound without having to worry about measuring out the speaker distances from the point of observation.
Daniel
#25
07-22-2004, 02:23 PM
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Tim Tim Tim...
whereas Bose an many other companies have made fortunes and great sound by carefully reflecting the sound waves,, bouncing them off a solid plate (Like a WINDSHIELD) will only shatter the wave length.
Unles something changed in sound waves in thelast 10 years, the high frequency wavelength shatters.
Low and Mid you do not need to worry about. Even though some will argue that it is not directional, it is still somewhat directional. owever, bouncing it off a plate serface will not interupt the wave length as much as the highs.
I'll respond more later whenI have time.
whereas Bose an many other companies have made fortunes and great sound by carefully reflecting the sound waves,, bouncing them off a solid plate (Like a WINDSHIELD) will only shatter the wave length.
Unles something changed in sound waves in thelast 10 years, the high frequency wavelength shatters.
Low and Mid you do not need to worry about. Even though some will argue that it is not directional, it is still somewhat directional. owever, bouncing it off a plate serface will not interupt the wave length as much as the highs.
I'll respond more later whenI have time.
#26
07-22-2004, 03:03 PM
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Originally posted by Tim Skelton
Menace, Menace, Menace. I hope that acoustics is not on the bar exam.
While I do not disagree that bouncing is a bad idea (depends on the installation--Bose made a whole company out of reflected sound),
Menace, Menace, Menace. I hope that acoustics is not on the bar exam.
While I do not disagree that bouncing is a bad idea (depends on the installation--Bose made a whole company out of reflected sound),
Not to even get started in this but if you ask any Audiophile what they think about Bose speakers you'll get a pretty good laugh. Bose has an excellent marketing department. They took a mediocre product and made it world known by advertising. Walk out of the street and ask a normal person to name a brand of speaker. 9 out 10 they will say Bose.
Some of there products are decent but for the same money you can get something 3 times better in most cases. Trying to credit an argument and reference Bose Research made me laugh.
Just my 2 cents, Carry on the Debate.
#27
07-22-2004, 03:06 PM
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Originally posted by l-menace
Tim Tim Tim...
whereas Bose an many other companies have made fortunes and great sound by carefully reflecting the sound waves,, bouncing them off a solid plate (Like a WINDSHIELD) will only shatter the wave length.
Unles something changed in sound waves in thelast 10 years, the high frequency wavelength shatters.
Low and Mid you do not need to worry about. Even though some will argue that it is not directional, it is still somewhat directional. owever, bouncing it off a plate serface will not interupt the wave length as much as the highs.
I'll respond more later whenI have time.
Tim Tim Tim...
whereas Bose an many other companies have made fortunes and great sound by carefully reflecting the sound waves,, bouncing them off a solid plate (Like a WINDSHIELD) will only shatter the wave length.
Unles something changed in sound waves in thelast 10 years, the high frequency wavelength shatters.
Low and Mid you do not need to worry about. Even though some will argue that it is not directional, it is still somewhat directional. owever, bouncing it off a plate serface will not interupt the wave length as much as the highs.
I'll respond more later whenI have time.
Here's some science text:
Reflection of sound waves off of surfaces can lead to one of two phenomenon - an echo or a reverberation. A reverberation often occurs in a small room with height, width, and length dimensions of approximately 17 meters or less. Why the magical 17 meters? The effect of a particular sound wave upon the brain endures for more than a tiny fraction of a second; the human brain keeps a sound in memory for up to 0.1 seconds. If a reflected sound wave reaches the ear within 0.1 seconds of the initial sound, then it seems to the person that the sound is prolonged. The reception of multiple reflections off of walls and ceilings within 0.1 seconds of each other causes reverberations - the prolonging of a sound. Since sound waves travel at about 340 m/s at room temperature, it will take approximately 0.1 s for a sound to travel the length of a 17 meter room and back, thus causing a reverberation (t = v/d = (340 m/s)/(34 m) = 0.1 s). This is why reverberations is common in rooms with dimensions of approximately 17 meters or less. Perhaps you have observed reverberations when talking in an empty room, when honking the horn while driving through a highway tunnel or underpass, or when singing in the shower. In auditoriums and concert halls, reverberations occasionally occur and lead to the displeasing garbling of a sound.
#28
07-22-2004, 03:19 PM
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Originally posted by TTA89
Just my 2 cents, Carry on the Debate.
Just my 2 cents, Carry on the Debate.
I'm just trying to figure out what he means by "shatter"... There is either a wave, interference or canceling...
The only thing happening with moving the tweeters to point at the windshield is you have to deal with tuning the reflection otherwise it will sound like crab as you hear more then one wave set.
If you put your tweeters too far away from your mids, you risk being unable to match the phase and effectively reduce your sound-stage, reducing the quality of the sound you can reproduce.
Dan
#29
07-22-2004, 04:38 PM
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ummm.....hello?....
What is shattering a sound wave. Can someone explain to me what happens to a wave when it "SHATTERS" Here's another question. Wave's are moving energy right? Sound is a compression of air molecules as it passes through a medium. Why does a wave of the "same" air get reflected/absorbed when it changes mediums? Sure frequency tends to become more directional as it increases but......HELP! I'M CONFUSED!!!
This isn't RF or Magnetic waves -and windshields aren't faraday cages!
CGORRIS - where are you?
What is shattering a sound wave. Can someone explain to me what happens to a wave when it "SHATTERS" Here's another question. Wave's are moving energy right? Sound is a compression of air molecules as it passes through a medium. Why does a wave of the "same" air get reflected/absorbed when it changes mediums? Sure frequency tends to become more directional as it increases but......HELP! I'M CONFUSED!!!
This isn't RF or Magnetic waves -and windshields aren't faraday cages!CGORRIS - where are you?
#30
07-22-2004, 04:39 PM
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doh.. still at work can't talk long.
SHATTER:
Think of it like this.
a tweeter is very directional in its sound wave. meaning you can AIM it as opposed to a sub.
Take a garden hose, put it on jet and aim it at the windshield of your car, what happens?
the direct beam of water hits the windshield and "shatters" all over hte place.
Same thing (KINDA) happens with a high frequency. the fluid wave length from the tweeter that is directed at the windshiled, hits the windshield at scatters all over the place.
I know there are diagrams of this on thei internet of the high frequency bouncing off a solid object different than a pouruos material that will absorb some of the frequency
SHATTER:
Think of it like this.
a tweeter is very directional in its sound wave. meaning you can AIM it as opposed to a sub.
Take a garden hose, put it on jet and aim it at the windshield of your car, what happens?
the direct beam of water hits the windshield and "shatters" all over hte place.
Same thing (KINDA) happens with a high frequency. the fluid wave length from the tweeter that is directed at the windshiled, hits the windshield at scatters all over the place.
I know there are diagrams of this on thei internet of the high frequency bouncing off a solid object different than a pouruos material that will absorb some of the frequency