Can any mufflers pass 90 decibels ?
07-30-2006, 11:46 AM
#11
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Re: Can any mufflers pass 90 decibels ?
had my boat tested after a ticket. and the gil switchalbes did not past read a 96. so i set up some down pipes to pass.
todd
todd
07-30-2006, 11:53 AM
#12
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Re: Can any mufflers pass 90 decibels ?
Originally Posted by Ratickle
Here is most of SAE J2500 testing procedures. It actually doesn't say transom, it says vertical projection. Does the NY law say SAE J2500 or 1 meter/1 meter? There is a huge difference when in court or testing under a strict set of rules set up by SAE Engineers.
Excerpt from SAE J2500
(copied and pasted from pdf)
4. Procedure
4.1 Measurement Site—A suitable site is a body of water free of large obstructions or reflective surfaces such as
buildings, boats other than those involved in this procedure, large embankments or breakwaters, etc. for a
minimum distance of 8 m (25 ft) from the boat being measured. The boat being tested shall either be moored
to a dock or lashed to another boat. If moored to a dock, the dock shall be of open construction so that it
presents a minimum of reflecting surfaces. If the measurement is made in open water, the boat being
evaluated shall be lashed to the measurement boat to prevent relative motion and to allow positioning of the
microphone in the prescribed location. The measurement boat shall be positioned to minimize reflected
sound.
4.2 Boat Operation—The engine shall be operated at low idle speed within the engine manufacturer's
recommended operating range, in neutral gear if so equipped. For motorboats without a neutral gear, the
engine shall be operated at its lowest operational speed. The engine shall be operated for a sufficient amount
of time to allow water to flow through the exhaust system before taking measurements.
4.3 Measurements
4.3.1 The microphone shall be placed at a distance of 1.2 to 1.5 m (4 to 5 ft) above the water and no closer than
1m (3.3 ft) from the vertical projection of any part of the boat in the area adjacent to the exhaust outlet(s).
4.3.2 The meter shall be set for slow response and the A-weighting network.
4.3.3 The observer reading the meter shall not be closer than arm's length from the microphone to minimize sound
reflections.
4.3.4 The applicable reading shall be the average sound level measured during a period when the background
sound level is at least 10 dB lower than the measured sound level. Background sound level includes wind effects, noise from boats other than the one being measured, wave action, boat wakes, and other extraneous
noises.
Peak readings of intermittent sound levels created by wave slaps or changes in sound level due to
wave action and/or engine speed variation shall not be included in the applicable reading.
4.3.5 The observer shall record the applicable reading and the background sound levels taken immediately before
and immediately after the applicable reading.
5. General Requirements
5.1 The measurements shall be conducted only by persons qualified by training to perform these measurements.
5.2 Proper use of all test instrumentation is essential to obtain valid measurements. Operating manuals or other
literature furnished by the instrument manufacturer should be consulted for both recommended operation of
the instrument, and precautions to be observed.
5.3 Proper acoustical calibration shall comprise the complete measurement system including extension cables,
etc. Field calibration shall be performed immediately before and after each test sequence.
5.4 A measurement shall be invalid if changes in the background sound level affect the applicable reading.
5.5 The use of the word "shall" in the procedure is to be understood to be mandatory, while the word "should" is to
be understood as advisory.
PREPARED BY THE SAE MARINE SOUND LEVEL SUBCOMMITTEE OF THE SAE MARINE TECHNICAL COMMITTEE AND THE SAE SPECIALIZED VEHICLE AND EQUIPMENT SOUND LEVEL COMMITTEE
Excerpt from SAE J2500
(copied and pasted from pdf)
4. Procedure
4.1 Measurement Site—A suitable site is a body of water free of large obstructions or reflective surfaces such as
buildings, boats other than those involved in this procedure, large embankments or breakwaters, etc. for a
minimum distance of 8 m (25 ft) from the boat being measured. The boat being tested shall either be moored
to a dock or lashed to another boat. If moored to a dock, the dock shall be of open construction so that it
presents a minimum of reflecting surfaces. If the measurement is made in open water, the boat being
evaluated shall be lashed to the measurement boat to prevent relative motion and to allow positioning of the
microphone in the prescribed location. The measurement boat shall be positioned to minimize reflected
sound.
4.2 Boat Operation—The engine shall be operated at low idle speed within the engine manufacturer's
recommended operating range, in neutral gear if so equipped. For motorboats without a neutral gear, the
engine shall be operated at its lowest operational speed. The engine shall be operated for a sufficient amount
of time to allow water to flow through the exhaust system before taking measurements.
4.3 Measurements
4.3.1 The microphone shall be placed at a distance of 1.2 to 1.5 m (4 to 5 ft) above the water and no closer than
1m (3.3 ft) from the vertical projection of any part of the boat in the area adjacent to the exhaust outlet(s).
4.3.2 The meter shall be set for slow response and the A-weighting network.
4.3.3 The observer reading the meter shall not be closer than arm's length from the microphone to minimize sound
reflections.
4.3.4 The applicable reading shall be the average sound level measured during a period when the background
sound level is at least 10 dB lower than the measured sound level. Background sound level includes wind effects, noise from boats other than the one being measured, wave action, boat wakes, and other extraneous
noises.
Peak readings of intermittent sound levels created by wave slaps or changes in sound level due to
wave action and/or engine speed variation shall not be included in the applicable reading.
4.3.5 The observer shall record the applicable reading and the background sound levels taken immediately before
and immediately after the applicable reading.
5. General Requirements
5.1 The measurements shall be conducted only by persons qualified by training to perform these measurements.
5.2 Proper use of all test instrumentation is essential to obtain valid measurements. Operating manuals or other
literature furnished by the instrument manufacturer should be consulted for both recommended operation of
the instrument, and precautions to be observed.
5.3 Proper acoustical calibration shall comprise the complete measurement system including extension cables,
etc. Field calibration shall be performed immediately before and after each test sequence.
5.4 A measurement shall be invalid if changes in the background sound level affect the applicable reading.
5.5 The use of the word "shall" in the procedure is to be understood to be mandatory, while the word "should" is to
be understood as advisory.
PREPARED BY THE SAE MARINE SOUND LEVEL SUBCOMMITTEE OF THE SAE MARINE TECHNICAL COMMITTEE AND THE SAE SPECIALIZED VEHICLE AND EQUIPMENT SOUND LEVEL COMMITTEE
Seems to me if you took pictures or video of the LEO conducting one of these tests you'd be able to find enough mistakes to beat the ticket in court. I don't see how they can accurately perform the test with so many procedures and variables.
07-30-2006, 02:44 PM
#13
Registered
Re: Can any mufflers pass 90 decibels ?
Originally Posted by Ratickle
Here is most of SAE J2500 testing procedures. It actually doesn't say transom, it says vertical projection. Does the NY law say SAE J2500 or 1 meter/1 meter? There is a huge difference when in court or testing under a strict set of rules set up by SAE Engineers.
Excerpt from SAE J2500
(copied and pasted from pdf)
4. Procedure
4.1 Measurement Site—A suitable site is a body of water free of large obstructions or reflective surfaces such as
buildings, boats other than those involved in this procedure, large embankments or breakwaters, etc. for a
minimum distance of 8 m (25 ft) from the boat being measured. The boat being tested shall either be moored
to a dock or lashed to another boat. If moored to a dock, the dock shall be of open construction so that it
presents a minimum of reflecting surfaces. If the measurement is made in open water, the boat being
evaluated shall be lashed to the measurement boat to prevent relative motion and to allow positioning of the
microphone in the prescribed location. The measurement boat shall be positioned to minimize reflected
sound.
4.2 Boat Operation—The engine shall be operated at low idle speed within the engine manufacturer's
recommended operating range, in neutral gear if so equipped. For motorboats without a neutral gear, the
engine shall be operated at its lowest operational speed. The engine shall be operated for a sufficient amount
of time to allow water to flow through the exhaust system before taking measurements.
4.3 Measurements
4.3.1 The microphone shall be placed at a distance of 1.2 to 1.5 m (4 to 5 ft) above the water and no closer than
1m (3.3 ft) from the vertical projection of any part of the boat in the area adjacent to the exhaust outlet(s).
4.3.2 The meter shall be set for slow response and the A-weighting network.
4.3.3 The observer reading the meter shall not be closer than arm's length from the microphone to minimize sound
reflections.
4.3.4 The applicable reading shall be the average sound level measured during a period when the background
sound level is at least 10 dB lower than the measured sound level. Background sound level includes wind effects, noise from boats other than the one being measured, wave action, boat wakes, and other extraneous
noises.
Peak readings of intermittent sound levels created by wave slaps or changes in sound level due to
wave action and/or engine speed variation shall not be included in the applicable reading.
4.3.5 The observer shall record the applicable reading and the background sound levels taken immediately before
and immediately after the applicable reading.
5. General Requirements
5.1 The measurements shall be conducted only by persons qualified by training to perform these measurements.
5.2 Proper use of all test instrumentation is essential to obtain valid measurements. Operating manuals or other
literature furnished by the instrument manufacturer should be consulted for both recommended operation of
the instrument, and precautions to be observed.
5.3 Proper acoustical calibration shall comprise the complete measurement system including extension cables,
etc. Field calibration shall be performed immediately before and after each test sequence.
5.4 A measurement shall be invalid if changes in the background sound level affect the applicable reading.
5.5 The use of the word "shall" in the procedure is to be understood to be mandatory, while the word "should" is to
be understood as advisory.
PREPARED BY THE SAE MARINE SOUND LEVEL SUBCOMMITTEE OF THE SAE MARINE TECHNICAL COMMITTEE AND THE SAE SPECIALIZED VEHICLE AND EQUIPMENT SOUND LEVEL COMMITTEE
Excerpt from SAE J2500
(copied and pasted from pdf)
4. Procedure
4.1 Measurement Site—A suitable site is a body of water free of large obstructions or reflective surfaces such as
buildings, boats other than those involved in this procedure, large embankments or breakwaters, etc. for a
minimum distance of 8 m (25 ft) from the boat being measured. The boat being tested shall either be moored
to a dock or lashed to another boat. If moored to a dock, the dock shall be of open construction so that it
presents a minimum of reflecting surfaces. If the measurement is made in open water, the boat being
evaluated shall be lashed to the measurement boat to prevent relative motion and to allow positioning of the
microphone in the prescribed location. The measurement boat shall be positioned to minimize reflected
sound.
4.2 Boat Operation—The engine shall be operated at low idle speed within the engine manufacturer's
recommended operating range, in neutral gear if so equipped. For motorboats without a neutral gear, the
engine shall be operated at its lowest operational speed. The engine shall be operated for a sufficient amount
of time to allow water to flow through the exhaust system before taking measurements.
4.3 Measurements
4.3.1 The microphone shall be placed at a distance of 1.2 to 1.5 m (4 to 5 ft) above the water and no closer than
1m (3.3 ft) from the vertical projection of any part of the boat in the area adjacent to the exhaust outlet(s).
4.3.2 The meter shall be set for slow response and the A-weighting network.
4.3.3 The observer reading the meter shall not be closer than arm's length from the microphone to minimize sound
reflections.
4.3.4 The applicable reading shall be the average sound level measured during a period when the background
sound level is at least 10 dB lower than the measured sound level. Background sound level includes wind effects, noise from boats other than the one being measured, wave action, boat wakes, and other extraneous
noises.
Peak readings of intermittent sound levels created by wave slaps or changes in sound level due to
wave action and/or engine speed variation shall not be included in the applicable reading.
4.3.5 The observer shall record the applicable reading and the background sound levels taken immediately before
and immediately after the applicable reading.
5. General Requirements
5.1 The measurements shall be conducted only by persons qualified by training to perform these measurements.
5.2 Proper use of all test instrumentation is essential to obtain valid measurements. Operating manuals or other
literature furnished by the instrument manufacturer should be consulted for both recommended operation of
the instrument, and precautions to be observed.
5.3 Proper acoustical calibration shall comprise the complete measurement system including extension cables,
etc. Field calibration shall be performed immediately before and after each test sequence.
5.4 A measurement shall be invalid if changes in the background sound level affect the applicable reading.
5.5 The use of the word "shall" in the procedure is to be understood to be mandatory, while the word "should" is to
be understood as advisory.
PREPARED BY THE SAE MARINE SOUND LEVEL SUBCOMMITTEE OF THE SAE MARINE TECHNICAL COMMITTEE AND THE SAE SPECIALIZED VEHICLE AND EQUIPMENT SOUND LEVEL COMMITTEE
Nordic95
07-30-2006, 02:46 PM
#14
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Re: Can any mufflers pass 90 decibels ?
Originally Posted by otis311
I was tested at 68db w/o mufflers !!
Nordic95
Racer
07-30-2006, 10:28 PM
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Re: Can any mufflers pass 90 decibels ?
Originally Posted by Ratickle
Here is most of SAE J2500 testing procedures. It actually doesn't say transom, it says vertical projection. Does the NY law say SAE J2500 or 1 meter/1 meter? There is a huge difference when in court or testing under a strict set of rules set up by SAE Engineers.
from the web site
Vessel Noise Enforcement Training
Noise & Sound Theory
The Law
Using a Noise Meter
Test 1: SAE J1970
Test 2: SAE J2005
Noise & Sound Theory
The Law
Using a Noise Meter
Test 1: SAE J1970
Test 2: SAE J2005
What is test 1970? I've never heard of it.
I always thought that 2005 said transom. My bad. But that could be an interesting loop hole on a boat like a Formula with silent thunder. Where is the exhaust "really" coming out? The transom outlets, or the silent thunder outlets. 1 meter of transom compared to 1 meter off teh silent thunder is 12-15" further back, which I would think would cut out a lot of noise.
07-30-2006, 10:30 PM
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Re: Can any mufflers pass 90 decibels ?
Do I understand the part where the background noise must be 10 db BELOW the engine? So if the engine reads 95, and the background reads 86, it is NOT a valid test?
07-31-2006, 05:46 PM
#19
Registered
Re: Can any mufflers pass 90 decibels ?
Duke, It is the test from shore. Also unenforceable under the current rules. They try to make it as if you are driving by shore and a water policeman with a DB meter gets a reading and you are hit with a big ticket. And yes, the 10 DB rule you have correctly interpreted. I currently believe Wisconsin has the most restrictive rules. Soon to be passed by Michigan (next year?)if they have their way.
The SAE J1970 standard Shoreline Sound Level Measurement Procedure and the SAE J2005
standard Stationary Sound Level Measurement Procedure for Pleasure Motorboats, were both
adopted in December 1991. These standards were the second and third boat noise measurement
standards created. SAE J1970 and J2005 were developed to provide alternative field procedures
for measuring sound level emitted from pleasure motorboats. Their development sought to
create a measurement standard directly emulating the 75 dBA shoreline noise limit in the Marine
Safety Act and to avoid the requirement of a pass-by course. The SAE J1970 and J2005 are the
only two boat noise standards currently specified by the Michigan Marine Safety Act.
The SAE J1970 Shoreline Sound Level Measurement Procedure, was adopted for
measurement of sound emitted by pleasure motorboats in operation on waterways where sound
level restrictions apply. The standard requires placing a sound level meter on the shore of a body
of water, a dock projecting out from the shore into the body of water, or a raft/boat moored to a
dock or anchored so that the sound level meter is not more than 6 meters from shore. The SPL
measurement is taken after the boat accelerates full throttle away from the measurement location
for 30 seconds to emulate the Michigan Marine Safety Act's requirement for a 300 foot offshore
distance to boats operating at full throttle. The sound level meter must to be placed 1.2 meters to
1.5 meters above the water and no less than 0.6 meters above the platform, or shore, surface
[SAE J1970]. The Michigan Marine Code sets a 75 dBA (fast) SPL maximum acceptable sound
level from this standard measurement procedure.
The SAE J1970 standard Shoreline Sound Level Measurement Procedure and the SAE J2005
standard Stationary Sound Level Measurement Procedure for Pleasure Motorboats, were both
adopted in December 1991. These standards were the second and third boat noise measurement
standards created. SAE J1970 and J2005 were developed to provide alternative field procedures
for measuring sound level emitted from pleasure motorboats. Their development sought to
create a measurement standard directly emulating the 75 dBA shoreline noise limit in the Marine
Safety Act and to avoid the requirement of a pass-by course. The SAE J1970 and J2005 are the
only two boat noise standards currently specified by the Michigan Marine Safety Act.
The SAE J1970 Shoreline Sound Level Measurement Procedure, was adopted for
measurement of sound emitted by pleasure motorboats in operation on waterways where sound
level restrictions apply. The standard requires placing a sound level meter on the shore of a body
of water, a dock projecting out from the shore into the body of water, or a raft/boat moored to a
dock or anchored so that the sound level meter is not more than 6 meters from shore. The SPL
measurement is taken after the boat accelerates full throttle away from the measurement location
for 30 seconds to emulate the Michigan Marine Safety Act's requirement for a 300 foot offshore
distance to boats operating at full throttle. The sound level meter must to be placed 1.2 meters to
1.5 meters above the water and no less than 0.6 meters above the platform, or shore, surface
[SAE J1970]. The Michigan Marine Code sets a 75 dBA (fast) SPL maximum acceptable sound
level from this standard measurement procedure.
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