Re: Can I increase the output of a tweeter?

Posted by Hans on December 08, 1999 at 02:25:10:
In Reply to: Can I increase the output of a tweeter? posted by Cico on
December 08, 1999 at 00:57:52:

> your best bet would be to open the other speaker and duplicate what
> you see, reverse engineering.

Perhaps I should clarify something. The speakers were recently
purchased used, and these electronic parts were clearly put on by the
previous owner as some kind of a modification. So I found no such
parts on the "good" tweeter when I checked to see how it was wired. My
presumption was that the reason the parts were put on in the first
place, was to get the "bad" dome tweeter to sound as dynamic and
detailed as the "good" dome tweeter.

> 'Series' connection is when the cap is connected in-line with the
> tweeter, the current must flow through the cap before it gets to the
> tweeter.

By this, I presume you mean one end of the cap is connected to the
wire, the other end to the tweeter terminal. Does "series" connection
in ths case automatically imply the cap should go to the positive
terminal, or does it depend on the situation?

> 'Parallel' is when the cap is connected across the tweeter. There is no
> cap in the way, just the wire, for the current.

By this, I presume you mean the 2 wires of the cap are connected to
the negative and positive terminals on the tweeter, (which connect them
to the negative/positive tweeter wires). I knew it could not have been
connected this way, because the wires on the cap are not long enough
to stretch across the diameter of the tweeter magnet.

> Usually the cap is in series with the tweeter. 4.7µF gives xo at around
> 4kHz, for a firstorder xo into 8ohms. Twice the frequency into 4ohms.
> It's also common for a resistor to be in series with the tweeter, so
> this is probably where it goes.

There is already a crossover network in the speaker. Do you mean that
despite this, a 4.7mF cap connected in series to the 4ohm tweeter
will have the effect of not passing any signal below 8khz to the
tweeter? I know that a resistor has the effect of blocking the flow of
a signal to a specific degree, depending on its value. I have basically
no idea what a capacitor does, though. So before I try wiring these
two parts as suggested, do you have an idea of what sonic effect they
might have on the tweeter (so I know what to listen for)? Would they
boost the output? Or would they more likely just reduce the tweeter's
general output, or reduce a certain part of the freq. range?

> So my guess is: Connect the capacitor and resistor in series with the
> tweeter, like a chain with the three things and wire between. The
> resistor and cap goes from positive terminal, then comes tweeter which
> has it's negative straight to negative connection on speaker
> post.(sometimes they're connected opposite phase)

By this schematic, do I presume correctly that you mean I am starting
with the positive-side tweeter wire (coming from speaker post), then
the resistor, then the cap, which is then connected directly to the
positive tweeter terminal (and I leave the negative side as it is,
connected straight to the speaker post)?

> It seems the parts were poorly connected. Remember the solder is only to
> hold an already good connection firmly together. Twist the wire to the
> component leads so it's well fastened, then solder.

Actually, the reason the part or parts came off, is because the
previous owner didn't even bother to solder them, he had just taped
them on with electrical tape! So I'm quite certain it wasn't part of
Energy's original design. In fact, they aren't even the original
tweeters.

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