megaphone louder?
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Joined: Sep 2010
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From: Phoenix '53, '88, '09 Big Twins
megaphones disperse the sound over a wider area
straight pipes project in a more narrow line ( think line-of sight)
this is over simplified, but high frequencies travel more in straight lines and are directional, low frequencies are less directional.
which is why it is easy to track 2 stroke in traffic, but harder to tell which car has the thumping bass system ( until you see the mirrors falling off)
there is no simple answer to your question as it is dependent on the frequency you are concerned with and the positon of the listener- behind, the side, on the bike etc.
and also the surroundings- a flat wall behind will bounce sound right back at the rider
a bike with turndowns will always sound louder to the rider than turn outs/ and exactly the opposite experience for the observer
also factor in any baffing or packing, without which in a megaphone, the exhaust gasses would loose velocity and performance would be affected.
Mike
straight pipes project in a more narrow line ( think line-of sight)
this is over simplified, but high frequencies travel more in straight lines and are directional, low frequencies are less directional.
which is why it is easy to track 2 stroke in traffic, but harder to tell which car has the thumping bass system ( until you see the mirrors falling off)
there is no simple answer to your question as it is dependent on the frequency you are concerned with and the positon of the listener- behind, the side, on the bike etc.
and also the surroundings- a flat wall behind will bounce sound right back at the rider
a bike with turndowns will always sound louder to the rider than turn outs/ and exactly the opposite experience for the observer
also factor in any baffing or packing, without which in a megaphone, the exhaust gasses would loose velocity and performance would be affected.
Mike
Last edited by mkguitar; Feb 18, 2013 at 11:30 AM.
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Road Captain
Joined: Jul 2007
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From: Kansas City
Thanks. I was comparing exhaust systems from Bassani. Looking at their 2>1 with the options of megaphone or strait pipe. So sounds like the megaphone would be "thumpier" than the strait but would reduce low end performance with low restriction baffles.
Extreme HDF Member
Joined: Sep 2010
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From: Phoenix '53, '88, '09 Big Twins
"straight pipe" generally means a straight pipe from the exhaust manifold about 33" to the exit, a few bends, no steps
i am not familiar with what bassani sells.
Mike
i am not familiar with what bassani sells.
Mike
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Road Captain
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From: Kansas City
You get either a strait, evenly round muffler with baffles, or a megaphone muffler with baffles. Shaped like a tumpet.
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Road Captain
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From: Kansas City
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