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Old 21st September 2009, 12:27 PM   #1
speedie is offline speedie  Australia
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Location: palmyra fremantle western australia
Default db meter

I was wondering if crossover verification could be achieved by the use of only a sound pressure meter
Would this idea work?
With testing for db drop in xo area could we say remove the minus lead from each driver to get readings i.e. check woofer only followed by each driver in order
It seems to me that db should be similar to say series or parallel concepts
I guess what I am trying to say is that if there is a db variation then the crossover is not a flat response?
Would anyone like to shed a little light!
Cheers speedie
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Old 21st September 2009, 01:08 PM   #2
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Quote:
Originally Posted by speedie View Post
I was wondering if crossover verification could be achieved by the use of only a sound pressure meter
Would this idea work?
With testing for db drop in xo area could we say remove the minus lead from each driver to get readings i.e. check woofer only followed by each driver in order
It seems to me that db should be similar to say series or parallel concepts
I guess what I am trying to say is that if there is a db variation then the crossover is not a flat response?
Would anyone like to shed a little light!
Cheers speedie
Would work in princliple, your reasoning is spot on.
But to get meaningfull results you must do it in free field (unless you have an anechoic chamber in your cellar), and make sure that you don't change anything to the speaker pos and mike pos between measurements.

You can also do it with the complete speaker, just take readings at small freq steps through the xover to see how it looks. Separate curves from each driver do not always add up algebraically because there's phase shift between them that you won't see with the SLM. So, come to think of it, only the last method is usefull.

jd
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Old 22nd September 2009, 12:55 AM   #3
speedie is offline speedie  Australia
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Thanks JD
It is an interesting concept, if we look at a crossover response graph, the intersection is always at a lower point than the flat line that we are tring to achieve so having said that where does the extra level of noise come from?
as one rolls off the other picks up, graphically there is a lower db rating
cheers Speedie
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