General SPL General discussion of Sound Pressure Level topics.

some interesting findings

Old Feb 23, 2005 | 08:16 AM
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has anyone ever played with the tracks on the end of the DB Drag CD? yes, the clipped signals?

well here is what I have found

the hard clipped signal was loudest(almost 3db over a sine wave) at low volume, but when used at full volume or as a burp for your highest SPL, it was actually quieter than a clean (slightly clipped)tone burp... Im still not sure if this is because the clipped recording is too short to get a full reading...and the TL requires a longer burp to measure your score.

has anyone else come across this?

be carefull when testing with hard clipped (square waves)signals as they have high DC content and can damage the coils alot faster than a clean signal
Old Feb 23, 2005 | 08:24 AM
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Peter why dont u try this, get 3 head units and hook them up to your amp, get 1 to play your peak note, another to play the note before it and the 3rd the note after it.......tell us all how much your spl gona go up (anywhere from 3 to 6 db's)

this was the problem with the euro guys last year, they would play the pink noise from their HU and use some special xover that would filter it down to the 3 HZ and then would input the signal into the amp, they got some crazy scores that way.
Old Feb 23, 2005 | 08:58 AM
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One box I had was louder using the clipped tone bursts...Every other box I have built has liked a straight sine wave burp better. Not sure why, but I would gain 1.2 ish by using track 87 instead of just 50 Hz.

-Rick
Old Feb 23, 2005 | 04:59 PM
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Originally posted by Prolifik:
Peter why dont u try this, get 3 head units and hook them up to your amp, get 1 to play your peak note, another to play the note before it and the 3rd the note after it.......tell us all how much your spl gona go up (anywhere from 3 to 6 db's)

this was the problem with the euro guys last year, they would play the pink noise from their HU and use some special xover that would filter it down to the 3 HZ and then would input the signal into the amp, they got some crazy scores that way.
I don't understand. Could you explain a little more.

X
Old Feb 23, 2005 | 07:51 PM
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Originally posted by Prolifik:
Peter why dont u try this, get 3 head units and hook them up to your amp, get 1 to play your peak note, another to play the note before it and the 3rd the note after it.......tell us all how much your spl gona go up (anywhere from 3 to 6 db's)

this was the problem with the euro guys last year, they would play the pink noise from their HU and use some special xover that would filter it down to the 3 HZ and then would input the signal into the amp, they got some crazy scores that way.
yeah Ive heard about that...I know how to do it...you just have to pretty well custom build a crossover..they have IC chips available to do that digitally filter even at slopes of 96db/octave..thats crazy concept..but yes it does work..and that is why mr harris has it stated somewhere in the rules that only a single head unit may be used

they are pretty well similating a square wave...but a square wave cannot be clipped at all as it is already a square wave..yeah i know it sounds f'd up...but hey...its phisics at its best...thats why we love the sport so much..inst it? the good challange
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