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      09-01-2011, 11:09 AM   #67
John Tanglewood
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Cool argument, I'm learning a lot that I didn't know before about sound waves!
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      09-01-2011, 11:38 AM   #68
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Quote:
Originally Posted by dizzyj View Post
lol, he was probably right.

Saw an M5 with an aftermarket exhaust. I was fully expecting to see some honda civic with a fart can come around the corner then saw the m5. I had the same reaction. What a waste of a car.
So you cant hear the difference between a 5.0l V10 and a 4-cylinder??
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      09-01-2011, 11:45 AM   #69
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Quote:
Originally Posted by Smokey View Post


Its funny cuz I've been there, LOL.
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      09-01-2011, 11:48 AM   #70
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Oh and as far as Sound Waves goes, my knowledge ends here:



Do not mess with him.
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      09-01-2011, 12:35 PM   #71
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whenever someone older than me talks shit on my car i just say "half your age, double your money"
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      09-01-2011, 12:49 PM   #72
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Quote:
Originally Posted by John Tanglewood View Post
Cool argument, I'm learning a lot that I didn't know before about sound waves!
^^^this.

So, if a tree falls in the woods......
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      09-01-2011, 02:40 PM   #73
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Quote:
Originally Posted by Dave IV View Post
this "simple-minded dolt" is currently collecting a generous pension from his police service and a salary from his current employer, who also offers a pension and 401K.
Ugh...pensions. Good for you but bad for our budget deficit. Private sector companies are all doing away with defined benefit pension plans....the same should be done with all civil/teaching/municipal/govt. jobs.


OP, people say some weird stuff out of nowhere. Shrug it off...he's just mad at life.
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      09-01-2011, 02:49 PM   #74
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Quote:
Originally Posted by Edward View Post
Ugh...pensions. Good for you but bad for our budget deficit. Private sector companies are all doing away with defined benefit pension plans....the same should be done with all civil/teaching/municipal/govt. jobs.


OP, people say some weird stuff out of nowhere. Shrug it off...he's just mad at life.

Least he worked for his pension. Put a limit on welfare and unemployment collection.
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      09-01-2011, 06:52 PM   #75
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Quote:
Originally Posted by Dave IV View Post
Refraction! Really? Refraction is the change in direction of a wave due to impedance changes in a medium or between mediums. For acoustic waves in the atmosphere refraction is typically be due to a temperature lapse (decreasing temp with increasing altitude) or temperature inversion (increasing temp with increasing altitude), which will cause an acoustic wave to bend upward or downward. It will not cause the wave to bend vertically (front to back). Reflection dwarfs refraction in the context we are discussing and it will never cause the wave to “wrap around” the motorcycle.

Your statement about point sources and parabolic reflectors is the first semi-correct statement you have made. Given a point source I can direct a wave in any direction I desire by manipulating the reflector. I can also widen or narrow its beam and manipulate its amplitude (again, search EIRP).

It seems that the fundamental mistake you are making is that you believe the source of the acoustic wave is at the opening of the motorcycle’s exhaust pipe. This is wrong. The source of the wave is the combustion that takes place in the engine. For the purpose of this discussion we will consider the combustion to be a point source that radiates an acoustic wave equally in all directions. Ahh, now we introduce the reflector…the combustion chamber acts as a reflector, directing the wave in one direction; through the exhaust valve. The wave then enters the exhaust pipe which acts as a waveguide. As the exhaust (an acoustic wave) exits the pipe it is directed toward the rear of the bike.

As mentioned earlier, acoustic waves in air travel by compression and rarefaction of the air molecules in the wave's direction of travel. Put your hand near to the opening of the exhaust pipe. You can feel the acoustic wave (the exhaust). As you move your hand further from the pipe opening the intensity of the wave decreases. If you place your hand to the side of the pipe, adjacent to the opening, you will not feel an acoustic wave (take care not to touch the pipe and confuse the vibration of the pipe with the acoustic wave).

In short, the acoustic wave travels in a conical straight line from the exhaust pipe, to the the rear of the bike. There is no magical property causing the wave to “make a U-turn or wrap around” the bike. If you are observing the bike while you and the bike are stationary you will hear the loud exhaust while standing in front of the bike. This is due to reflections (NOT refraction) of the wave from objects near the bike. Once the bike is moving the effect of the reflections is minimized and the loud exhaust will be almost entirely noticeable only from the rear of the bike.

The argument that a loud bike is a safe bike is a load of crap, unless someone is going to run you over from behind. On the other hand someone may intentionally run you over from behind for having a loud, obnoxious bike.
Unbelievable.
You win. Everything you've said is technically correct and not applicable to our discussion. I'm guessing you're very popular amongst your staff.

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      09-01-2011, 07:13 PM   #76
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Wait, so now it's not cool on M3post to have an exhaust any more?

Dang
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      09-01-2011, 07:49 PM   #77
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Quote:
Originally Posted by Radiation Joe View Post
Unbelievable.
You win. Everything you've said is technically correct and not applicable to our discussion. I'm guessing you're very popular amongst your staff.
This has nothing to do with me winning. I have described the physical principles that govern propagation of acoustic waves and I am correct. I have described some of the science behind the principles and provided some real-life examples.

On the other hand the best you could come up with is a variation on ‘yes it does’ or ‘no it doesn’t’ and a few amateur attempts at insults. Sort of childish.

If, as you stated, you are “no amateur in the field of acoustics” and “have been presenting the results of acoustic resonance calculations and showing the empirical evidence of same within the nuclear industry for years” you should be able to call on some of that knowledge and present a defense of your position with a little technical support.

If you continue to disagree with my position, please, by all means, present a logical response supported by some scientific or technical facts.

Frankly, I don’t believe you have the background to do so. I do suspect that when you state that you have “been presenting the results of acoustic resonance calculations and showing the empirical evidence of same within the nuclear industry for years” what you really mean is that you are the guy simply responsible for running the projector.

I may be wrong, because as I recall I am the ”simple-minded dolt”

See ya'
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Last edited by Dave2; 09-01-2011 at 08:02 PM.
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      09-01-2011, 07:58 PM   #78
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How about you both shut the fuck up and let us talk about awkward moments in our M's.
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Quote:
Originally Posted by ES_TRADER
Use the stick like u would a manual. If that doesn't work, put it in D mode and put both hands at 10 and 2. If that doesn't work, just sit on your right hand.
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      09-01-2011, 08:06 PM   #79
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Well, guys.., to end this discussion nicely for everyone,
(Since, we also feel a bit responsible for this public reaction and behavior),
Who else wants this awesome Meisterschaft "GT2" exhaust system for your M3?
Please call in next 5 mins, we will give out one "GT2" unit for FREE!!
Call us NOW!! NO B.S.

Qualifying Condition for this event:
You must own an E9x M3 (your own, not your dads) with stock OE system.

GTHAUS
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      09-01-2011, 08:08 PM   #80
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Quote:
Originally Posted by GTHAUS View Post
Well, guys.., to end this discussion nicely for everyone,
(Since, we also feel a bit responsible for this public reaction and behavior),
Who else wants this awesome Meisterschaft "GT2" exhaust system for your M3?
Please call in next 5 mins, we will give out one "GT2" unit for FREE!!
Call us NOW!! NO B.S.

Qualifying Condition for this event:
You must own an E9x M3 (your own, not your dads) with stock OE system.

GTHAUS
Can i has exhaust? I will pay shipping to AUS
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Quote:
Originally Posted by ES_TRADER
Use the stick like u would a manual. If that doesn't work, put it in D mode and put both hands at 10 and 2. If that doesn't work, just sit on your right hand.
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      09-01-2011, 08:09 PM   #81
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You need to call us to get this unit.

GTHAUS
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      09-01-2011, 08:14 PM   #82
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No lucky winner today. Time is up.
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      09-02-2011, 02:31 AM   #83
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Quote:
Originally Posted by Totti View Post
How about you both shut the fuck up and let us talk about awkward moments in our M's.


Yeah I had an awkward moment in my M3 just recently....I stumbled upon this thread on my iPhone and thought it was a great topic...then I wasted 10 mins of my life reading about sound waves.

Here's an oldie but a goodie...

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      09-02-2011, 04:40 AM   #84
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      09-02-2011, 02:01 PM   #85
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Quote:
Originally Posted by Totti View Post
How about you both shut the fuck up and let us talk about awkward moments in our M's.

OK, then, here is my awkward M3 moment. Earlier this summer I am driving down to our shore house in the M3 with my wife and her sister. We are all having a pleasant conversation when my sister-in-law leans forward from the back seat, sticks her head between the front seats, looks directly at my wife, and says, "I want to suck Dave's dick".

I was a dumbfounded. For the remainder of the ride my wife and her sister had a pleasant, often humorous, conversation regarding the justification and merits of my sister-in-law sucking my dick. As you might imagine I was not sure what to do, say, or think.

No, it never did get sucked. Turns out it was actually a set-up between them just to screw with me a bit.
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      09-02-2011, 02:06 PM   #86
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Quote:
Originally Posted by Dave IV View Post
OK, then, here is my awkward M3 moment. Earlier this summer I am driving down to our shore house in the M3 with my wife and her sister. We are all having a pleasant conversation when my sister-in-law leans forward from the back seat, sticks her head between the front seats, looks directly at my wife, and says, "I want to suck Dave's dick".

I was a dumbfounded. For the remainder of the ride my wife and her sister had a pleasant, often humorous, conversation regarding the justification and merits of my sister-in-law sucking my dick. As you can imagine I was not sure what to do, say, or think.

No, it never did get sucked. Turns out it was actually a set-up between them just to screw with me a bit.
You sounded so uptight in your other posts, but you just redeemed yourself
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      09-02-2011, 03:20 PM   #87
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Quote:
Originally Posted by Smokey View Post
You sounded so uptight in your other posts, but you just redeemed yourself
I'm diverse.

Those other posts... well, someone comes in here and makes an unprovoked, albeit feeble, attempt to insult me...action needed to be taken.
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      09-02-2011, 04:03 PM   #88
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Quote:
Originally Posted by Dave IV View Post
...In short, the acoustic wave travels in a conical straight line from the exhaust pipe, to the the rear of the bike. There is no magical property causing the wave to “make a U-turn or wrap around” the bike. If you are observing the bike while you and the bike are stationary you will hear the loud exhaust while standing in front of the bike. This is due to reflections (NOT refraction) of the wave from objects near the bike. Once the bike is moving the effect of the reflections is minimized and the loud exhaust will be almost entirely noticeable only from the rear of the bike...
If we were floating 10,000 feet off the ground, not moving, with no clouds or wind, and I was facing a one of these loud Harleys 5 feet in front of me, would I hear none of the sound coming out of the tailpipe? With nothing for the sound to reflect off of, would it then not make any difference what kind of exhaust the motorcycle had? If I'm understanding this correctly, I would hear some sound from the engine but not the sound directed out the exhaust pipe.

OK, I'm not challenging you on this. I'm just curious.
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