Page 1 of 1
all in the interest of science
Posted: Mon Nov 23, 2009 11:01 am
by Aladinsaneuk
following on from the first top gear of the new series, I went out and got a DB meter for my iphone -
http://www.studiosixdigital.com/spl_meter.html
(Cost a whole 59 pence!)
now I wanted this to check roughly what my exhausts are sound wise - apparently it is accurate to +/- 2db
so... the results
on my falco with its twin high mount mille renegade exhausts.... 103.9 db with the baffles in
just thought i would share as it would seem i am right on the edge for my local track....
bugger!
Posted: Mon Nov 23, 2009 11:19 am
by D-Rider
At what distance did you measure? - sound pressure reduces according to an inverse square law based on distance.
Also what angle did you measure from?
+/- 2dB is fairly significant - it's a logarithmic scale with every 3 dB representing a doubling of power.
Posted: Mon Nov 23, 2009 12:09 pm
by Paulh
Most tracks will measure in accordance with ACU regs which stipulate revs and distance / angle from exhaust.
For a 1000cc twin this is at 5000revs, at an angle of 45° measured from the centre-line of the exhaust end and at the height of the
exhaust pipe, but at least 20 cm above the ground. If this is not possible, the measurement can be taken at 45° upwards.
I've always found my bike reads more on a trackday than when measured on a race day - no use complaining though as its their track and their rules.
Posted: Mon Nov 23, 2009 12:10 pm
by Aladinsaneuk
approx 3 feet from tail cluster, at tick over
and i know it is not exact but gives an idea....
Posted: Mon Nov 23, 2009 12:16 pm
by Paulh
Aladinsaneuk wrote:approx 3 feet from tail cluster, at tick over
and i know it is not exact but gives an idea....
Too far away and revs too low - might be worth checking in accordance with ACU guidlines to see what it it might read at a trackday.
I bought a cheapish (£9.99) meter from Maplins which seems pretty accurate compared to the track ones.