[SOT] Testing Speakers

[gatesj at mailblocks.com (John Gates)]

I'm fairly sure I remember that a high pass passive crossover contains 
capacitors inline with the speaker and inductance coils in parallel 
with the speaker for high pass.  I believe it's just the opposite for 
low pass, coils inline and caps across.  A 6db/oct crossover would 
simply have a cap or coil inline.  A 12db/oct crossover would have the 
cap or coil and then the opposite component on the speaker side of that 
first component, e.g. a cap inline on the amp side and then a coil 
across toward the speaker from the cap.  Polarity is reversed however 
through that setup.  Only an odd number of components retains polarity 
IIRC, i.e. an 18db/oct setup is one component inline, then the other 
type of component across, then the first type of component inline 
again, this is the favored setup.

Of course we're talking about passive crossovers here also.

Therefore, low pass would show continuity but high pass would not.

Or I could be completely wrong on this, It's completely from memory.

John Gates
--
'97 Jetta GLX
'85 Scirocco

-----Original Message-----
From: T Berk <bayareaberk@yahoo.com>
To: Brad Sterling <bgsterling@bluebottle.com>; scirocco-l@scirocco.org
Sent: Wed, 5 Oct 2005 12:24:53 -0700 (PDT)
Subject: Re: [SOT] Testing Speakers

--- Brad Sterling <bgsterling@bluebottle.com> wrote:
<A story of failing stereo (re)installation>


Divide and conquer my friend. Swap the Left for the
Right components, one at a time until you have
revealed the trouble;

- Temporarily swap the leads from the Head Unit, Left
for Right. Does the problem follow or remain on that
same side?

- Swap a speaker at the end of the chain, does the
problem follow? (btw, a 9v battery makes for a decent
speaker verify-er: it's got enough juice to push or
pull the 'cone' one way or the other.) Great for
verifying Phase also. (As in having all your speakers
pushing 'out' together vs fighting each other.

- Bypass the x-over, just on low power, and see if the
Head Unit to Speaker connections are OK.

All of these check basic function. If you want to
break out the meter you are going to want to check
Voltage w/ the power ON and Continuity (and/or
Resistance [or lack there of]) w/ the Power OFF.

Off the top of my head checking for Cont through a
x-over should work but running signal down the thing
sounds like a win/win to me.


hth,
TBerk



		
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