an you safely power just one coil in a dual-voice-coil sub? I
imagine it would be a good idea to short the terminals for the other
coil together.
Would just using one coil change the Thiele-Small parameters
of the sub? If so, would the changes be predictable?

Thanks for any input. I have a friend that had two DVC 4-ohm subs
that he was going to series-parallel into a single 4-ohm load, but
one of the speakers was irrepairably damaged in an unrelated incident.
He asked me if he could just use one voice coil of the remaining sub,
since that's a 4-ohm load, and I didn't have a good answer for him.

Scott Gardner

I've always been told by everyone I've ever talked to with more knowledge
than me that it's not good to run 1 coil of a DVC sub. It would be nice to
know why though.





Paul Vina



"Scott Gardner" wrote in message
...
an you safely power just one coil in a dual-voice-coil sub? I
imagine it would be a good idea to short the terminals for the other
coil together.
Would just using one coil change the Thiele-Small parameters
of the sub? If so, would the changes be predictable?

Thanks for any input. I have a friend that had two DVC 4-ohm subs
that he was going to series-parallel into a single 4-ohm load, but
one of the speakers was irrepairably damaged in an unrelated incident.
He asked me if he could just use one voice coil of the remaining sub,
since that's a 4-ohm load, and I didn't have a good answer for him.

Scott Gardner

I've seen it posted here before that it can be done if you short the unused
coil.


"Paul Vina" wrote in message
news:8pMzb.421028$HS4.3345794@attbi_s01...
I've always been told by everyone I've ever talked to with more knowledge
than me that it's not good to run 1 coil of a DVC sub. It would be nice
to
know why though.





Paul Vina



"Scott Gardner" wrote in message
...
an you safely power just one coil in a dual-voice-coil sub? I
imagine it would be a good idea to short the terminals for the other
coil together.
Would just using one coil change the Thiele-Small parameters
of the sub? If so, would the changes be predictable?

Thanks for any input. I have a friend that had two DVC 4-ohm subs
that he was going to series-parallel into a single 4-ohm load, but
one of the speakers was irrepairably damaged in an unrelated incident.
He asked me if he could just use one voice coil of the remaining sub,
since that's a 4-ohm load, and I didn't have a good answer for him.

Scott Gardner

What do you mean short the other coil?
Short is the most over used electrical word.

The sub is designed for 2 VC to push the sub and I image if you onl
use one VC the sub would lack control (precision).

he only thing I can figure you mean by shoring the other VC i
attaching the positive to the negative, wich would change nothing i
there was no power to the coil in the first place

-
Gma
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Yes, I meant connecting the two terminals of the unused coil together.
The reason for this is that if you don't, the induced current from the
coil that you are using will cause a voltage across the unused
terminals that could work against the speaker cone movement. Shorting
the unused terminals together is just to prevent that.

Scott

On Fri, 05 Dec 2003 02:00:06 GMT, Gmac
wrote:


What do you mean short the other coil?
Short is the most over used electrical word.

The sub is designed for 2 VC to push the sub and I image if you only
use one VC the sub would lack control (precision).

he only thing I can figure you mean by shoring the other VC is
attaching the positive to the negative, wich would change nothing if
there was no power to the coil in the first place.


--
Gmac
------------------------------------------------------------------------
Posted via RealCarAudio.com - The checkmate of the caraudio community.
http://www.RealCarAudio.com
Gmac's Profile: http://www.realcaraudio.com/forums/m...info&userid=10
View this thread: http://www.realcaraudio.com/forums/s...threadid=41004

he only thing I can figure you mean by shoring the other VC is
attaching the positive to the negative, wich would change nothing if
there was no power to the coil in the first place.


i think Mark Z. could explain it better.

OK maybye this is far fetched.... In my acoustics class we learned an
objects resonant frequency is a function of its mass (and other things)
Add mass to an object and you alter the resonant frequency, (principle
behind dynamat).

Would the Fs be lower running one coil by itself? Would the unused
portion of voice coil present more mass (dead weight) to the one active
coil? Would this lower the resonance of the assembly (IE cone), and
change the suspensions dampening characteristics?

Just thinking...
Garrett




Scott Gardner wrote:

an you safely power just one coil in a dual-voice-coil sub? I
imagine it would be a good idea to short the terminals for the other
coil together.
Would just using one coil change the Thiele-Small parameters
of the sub? If so, would the changes be predictable?

Thanks for any input. I have a friend that had two DVC 4-ohm subs
that he was going to series-parallel into a single 4-ohm load, but
one of the speakers was irrepairably damaged in an unrelated incident.
He asked me if he could just use one voice coil of the remaining sub,
since that's a 4-ohm load, and I didn't have a good answer for him.

Scott Gardner

Paul, there's no reason not to. The only "safety" consideration is that the
power would be concentrated in one coil instead of two, thereby lowering the
power handling characteristics of the driver.

However, contrary to popular belief, you don't halve the power handling when
using only one coil. Not even close. It's only a slight decrease. This
makes sense because the other coil is acting almost as a sink.

"Paul Vina" wrote in message
news:8pMzb.421028$HS4.3345794@attbi_s01...
I've always been told by everyone I've ever talked to with more knowledge
than me that it's not good to run 1 coil of a DVC sub. It would be nice
to
know why though.





Paul Vina



"Scott Gardner" wrote in message
...
an you safely power just one coil in a dual-voice-coil sub? I
imagine it would be a good idea to short the terminals for the other
coil together.
Would just using one coil change the Thiele-Small parameters
of the sub? If so, would the changes be predictable?

Thanks for any input. I have a friend that had two DVC 4-ohm subs
that he was going to series-parallel into a single 4-ohm load, but
one of the speakers was irrepairably damaged in an unrelated incident.
He asked me if he could just use one voice coil of the remaining sub,
since that's a 4-ohm load, and I didn't have a good answer for him.

Scott Gardner

What do you mean short the other coil?
Short is the most over used electrical word.

Short has a well-defined meaning. In this case, it's being used to describe
tying the two terminals of the coil together.


The sub is designed for 2 VC to push the sub and I image if you onl
use one VC the sub would lack control (precision).

What do you mean by lack precision? If the coil is shorting, it's still
providing the same brake that would exist if both coils were being powered.


he only thing I can figure you mean by shoring the other VC i
attaching the positive to the negative, wich would change nothing i
there was no power to the coil in the first place

No, it changes a lot. It allows current to flow through that coil. That
is, it closes the loop. The current that flows is due to ampere's law (or
is it faraday's? I get them confused too often). A current will flow
through a coil moving in a magnetic field.

Yes, I meant connecting the two terminals of the unused coil together.
The reason for this is that if you don't, the induced current from the
coil that you are using will cause a voltage across the unused
terminals that could work against the speaker cone movement. Shorting
the unused terminals together is just to prevent that.

Quite the opposite. Shorting it allows a current to flow. This current
provides an electrical brake which works towards restoring the Qts back to
what it is with both coils hooked up.

The weight is the same in both cases though.

"sanitarium" wrote in message
...
OK maybye this is far fetched.... In my acoustics class we learned an
objects resonant frequency is a function of its mass (and other things)
Add mass to an object and you alter the resonant frequency, (principle
behind dynamat).

Would the Fs be lower running one coil by itself? Would the unused
portion of voice coil present more mass (dead weight) to the one active
coil? Would this lower the resonance of the assembly (IE cone), and
change the suspensions dampening characteristics?

Just thinking...
Garrett




Scott Gardner wrote:

an you safely power just one coil in a dual-voice-coil sub? I
imagine it would be a good idea to short the terminals for the other
coil together.
Would just using one coil change the Thiele-Small parameters
of the sub? If so, would the changes be predictable?

Thanks for any input. I have a friend that had two DVC 4-ohm subs
that he was going to series-parallel into a single 4-ohm load, but
one of the speakers was irrepairably damaged in an unrelated incident.
He asked me if he could just use one voice coil of the remaining sub,
since that's a 4-ohm load, and I didn't have a good answer for him.

Scott Gardner

an you safely power just one coil in a dual-voice-coil sub? I
imagine it would be a good idea to short the terminals for the other
coil together.

You can do that if you want to maintain the Qts of the driver. However,
sometimes people want to change it by changing the Qes. This could be done
by shorting the terminals of the unused coil with a resistor. Or "dial it
in" with a pot!

Would just using one coil change the Thiele-Small parameters
of the sub? If so, would the changes be predictable?

Thanks for any input. I have a friend that had two DVC 4-ohm subs
that he was going to series-parallel into a single 4-ohm load, but
one of the speakers was irrepairably damaged in an unrelated incident.
He asked me if he could just use one voice coil of the remaining sub,
since that's a 4-ohm load, and I didn't have a good answer for him.

The only other consideration is that the power handling can slightly
decrease by doing so. IMO, unless you want to be able to adjust the Qes
with a pot, there's no benefit to doing this, because of the power issue
(unless you're using a monster sub and it doesn't matter). But in his case,
it would probably be a pretty good idea.