Sound level meter on offer at cpc - Drifting forum

djbolf · 07-05-2008, 03:31

Digital Sound Level Meter

Is a good price , and might come in handy for someone...

MJG · 07-05-2008, 07:05

It's half as accurate as most common units seem to be though. This is +/- 3.5dB but most of them are 1.5dB. I thought about getting one but since I only plan on building the one e30 for a long time I don't think it'd warrant the spend. Would definately save some anger at the track though if the car was a bit over!

skylineslider · 07-05-2008, 14:31

+1 db is a doubling in volume sothats a large error range imo,it cost me nearly 300 to buy a decent db meter setup,i cant see how these are that useful

fwiw my 140db stereo measured 103db on one of these

jason b · 10-05-2008, 01:35

Quote:

Originally Posted by skylineslider

+1 db is a doubling in volume sothats a large error range imo,it cost me nearly 300 to buy a decent db meter setup,i cant see how these are that useful

fwiw my 140db stereo measured 103db on one of these

FAIL

dB sound pressure levels operate on a logarithmic scale, +3dB is a doubling of actual energy, +10dB is a perceived doubling of loudness by a human ear. Sound meter readings also depend on the weighting coefficients that you are using and averaging settings etc etc. A perfect human ear can only just detect a 1dB change in sound pressure level and I seriously hope you didnt spend £300 on a sound meter if you dont have a clue about acoustics! - I also doubt your stereo is 140dB (maybe at one or two tiny impulses)- equivalent sound pressure to sub 100 feet from a jumbo jet engine at full thrust, or to put it another way, the maximum recommended sound pressure whilst wearing ear defenders!

skylineslider · 10-05-2008, 01:56

yeah ok you got me on the 3db thing
ive made 140.2db at 55hz,so yes at one frequency but does that matter? i used a known quantity againt the cheap meter and it didnt come close,unless im really to believe that a 30 pound meter is going to be better than a pro sound level meter?

or is measuring sound in atmospheric conditions different from sound pressure measuring in a cars cabin?

jason b · 10-05-2008, 02:08

Depends if you know how to use the professional sound level meter

, for example it is possible to make sounds appear louder or quieter than they are by changing the averaging settings i.e. a "fast" setting will give the impression of a greater sound pressure level than actually exists due to faster averaging times and the impulsive nature of many sounds. It is easily possible to hit those kind of decibel levels as peaks (a balloon bursting for eg), but it must be a very hefty sound setup to maintain an average of that kind of pressure (i.e. a really good amp with high rms output not peak rating!)

skylineslider · 10-05-2008, 02:13

i can play at that level for about three minutes,the coils get a bit whiffy after that.
afaik i can only alter the sample rate of the display itself so you can see the waveform over a longer time and detect clip better

07-05-2008, 03:31	#1 (permalink)
djbolf BMW 24v Tramp Join Date: Dec 2005 Location: Manchester Posts: 1,348	Sound level meter on offer at cpc Digital Sound Level Meter Is a good price , and might come in handy for someone...

10-05-2008, 01:56	#5 (permalink)
skylineslider tail slider Join Date: Apr 2007 Location: swansea Posts: 81	yeah ok you got me on the 3db thing ive made 140.2db at 55hz,so yes at one frequency but does that matter? i used a known quantity againt the cheap meter and it didnt come close,unless im really to believe that a 30 pound meter is going to be better than a pro sound level meter? or is measuring sound in atmospheric conditions different from sound pressure measuring in a cars cabin? Last edited by skylineslider : 10-05-2008 at 02:06.

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07-05-2008, 07:05	#2 (permalink)
MJG Most wanted Join Date: Oct 2004 Location: Derby, England Posts: 9,624	It's half as accurate as most common units seem to be though. This is +/- 3.5dB but most of them are 1.5dB. I thought about getting one but since I only plan on building the one e30 for a long time I don't think it'd warrant the spend. Would definately save some anger at the track though if the car was a bit over!

07-05-2008, 14:31	#3 (permalink)
skylineslider tail slider Join Date: Apr 2007 Location: swansea Posts: 81	+1 db is a doubling in volume sothats a large error range imo,it cost me nearly 300 to buy a decent db meter setup,i cant see how these are that useful fwiw my 140db stereo measured 103db on one of these

10-05-2008, 02:08	#6 (permalink)
jason b doughnutter Join Date: Mar 2008 Posts: 56	Depends if you know how to use the professional sound level meter , for example it is possible to make sounds appear louder or quieter than they are by changing the averaging settings i.e. a "fast" setting will give the impression of a greater sound pressure level than actually exists due to faster averaging times and the impulsive nature of many sounds. It is easily possible to hit those kind of decibel levels as peaks (a balloon bursting for eg), but it must be a very hefty sound setup to maintain an average of that kind of pressure (i.e. a really good amp with high rms output not peak rating!)

10-05-2008, 02:13	#7 (permalink)
skylineslider tail slider Join Date: Apr 2007 Location: swansea Posts: 81	i can play at that level for about three minutes,the coils get a bit whiffy after that. afaik i can only alter the sample rate of the display itself so you can see the waveform over a longer time and detect clip better