[GregS[_3_]]

In article , Chris Hornbeck wrote:
On Wed, 3 Dec 2008 06:20:58 -0800 (PST), Mark
wrote:

For four identical speakers in series-parallel, the load
to the amplifier is the same as that of one of the speakers,
and each speaker gets 1/2 the voltage and 1/2 the current
from the amplifier, so sees the same source impedance as
a single speaker.

the question is not about what load the AMP sees, you are correct what
you said about what load the amp sees but that is not in question, the
question I am discussing is not what load that the amp sees but rather
what does each speaker see as a source Z driving it...this is what
determines the damping factor for the speaker..

in the case of one speaker, the speaker obviously sees the output Z
of the amp.

The question at hand is what does each speaker see as a driving Z when
two speakers are connected in series.. and it is not a simple
question as it first appears.....

It's certainly interesting, and Don's analysis assuming perfect
similarity is great. Duh, the guy's solid.

But I think that the key to the puzzle is contained in the identity
of the series-parallel quad load and a single speaker load. The
amplifier cannot distinguish between the quad and the single. It
operates exactly the same with either load at any particular
electrical output level.


I find they can add acoustically very nicely. You simply have to use
any gain incorporated into a design, else things will not add up right.

greg

[Mark]

On Dec 4, 8:36*am, (GregS) wrote:
In article , Chris Hornbeck wrote:





On Wed, 3 Dec 2008 06:20:58 -0800 (PST), Mark
wrote:

For four identical speakers in series-parallel, the load
to the amplifier is the same as that of one of the speakers,
and each speaker gets 1/2 the voltage and 1/2 the current
from the amplifier, so sees the same source impedance as
a single speaker.

the question is not about what load the AMP sees, you are correct what
you said about what load the amp sees but that is not in question, the
question I am discussing is not what load that the amp sees but rather
what does each speaker see as a source Z driving it...this is what
determines the damping factor for the speaker..

in the case of one speaker, the speaker obviously sees the output Z
of the amp.

The question at hand is what does each speaker see as a driving Z when
two speakers are connected in series.. *and it is not a simple
question as it first appears.....

It's certainly interesting, and Don's analysis assuming perfect
similarity is great. Duh, the guy's solid.

But I think that the key to the puzzle is contained in the identity
of the series-parallel quad load and a single speaker load. The
amplifier cannot distinguish between the quad and the single. It
operates exactly the same with either load at any particular
electrical output level.

I find they can add acoustically very nicely. You simply have to use
any gain incorporated into a design, else things will not add up right.

greg- Hide quoted text -

- Show quoted text -

Greg,

by the way, I was able to find a copy of Part 1 of the papaer you
quoted on the web as well as this related paper:

http://www.diyspeakers.net/Articles/...G%20FACTOR.pdf

but I was not able to find the Part 2 that you mentioned.

Can you post a link to Part 2?

thanks

Mark

[GregS[_3_]]

In article , Mark wrote:
On Dec 4, 8:36=A0am, (GregS) wrote:
In article , Chris Hornbeck =
wrote:





On Wed, 3 Dec 2008 06:20:58 -0800 (PST), Mark
wrote:

For four identical speakers in series-parallel, the load
to the amplifier is the same as that of one of the speakers,
and each speaker gets 1/2 the voltage and 1/2 the current
from the amplifier, so sees the same source impedance as
a single speaker.

the question is not about what load the AMP sees, you are correct what
you said about what load the amp sees but that is not in question, the
question I am discussing is not what load that the amp sees but rather
what does each speaker see as a source Z driving it...this is what
determines the damping factor for the speaker..

in the case of one speaker, the speaker obviously sees the output Z
of the amp.

The question at hand is what does each speaker see as a driving Z when
two speakers are connected in series.. =A0and it is not a simple
question as it first appears.....

It's certainly interesting, and Don's analysis assuming perfect
similarity is great. Duh, the guy's solid.

But I think that the key to the puzzle is contained in the identity
of the series-parallel quad load and a single speaker load. The
amplifier cannot distinguish between the quad and the single. It
operates exactly the same with either load at any particular
electrical output level.

I find they can add acoustically very nicely. You simply have to use
any gain incorporated into a design, else things will not add up right.

greg- Hide quoted text -

- Show quoted text -

Greg,

by the way, I was able to find a copy of Part 1 of the papaer you
quoted on the web as well as this related paper:

http://www.diyspeakers.net/Articles/...G%20FACTOR.pdf

but I was not able to find the Part 2 that you mentioned.

Can you post a link to Part 2?

I didn't have time to read through it, looks like little more explanation.

http://zekfrivolous.com/sub/usenet/pierce/damp2.txt

greg

[Mark]

On Dec 4, 10:14*am, (GregS) wrote:
In article , Mark wrote:





On Dec 4, 8:36=A0am, (GregS) wrote:
In article , Chris Hornbeck =
wrote:

On Wed, 3 Dec 2008 06:20:58 -0800 (PST), Mark
wrote:

For four identical speakers in series-parallel, the load
to the amplifier is the same as that of one of the speakers,
and each speaker gets 1/2 the voltage and 1/2 the current
from the amplifier, so sees the same source impedance as
a single speaker.

the question is not about what load the AMP sees, you are correct what
you said about what load the amp sees but that is not in question, the
question I am discussing is not what load that the amp sees but rather
what does each speaker see as a source Z driving it...this is what
determines the damping factor for the speaker..

in the case of one speaker, the speaker obviously sees the output Z
of the amp.

The question at hand is what does each speaker see as a driving Z when
two speakers are connected in series.. =A0and it is not a simple
question as it first appears.....

It's certainly interesting, and Don's analysis assuming perfect
similarity is great. Duh, the guy's solid.

But I think that the key to the puzzle is contained in the identity
of the series-parallel quad load and a single speaker load. The
amplifier cannot distinguish between the quad and the single. It
operates exactly the same with either load at any particular
electrical output level.

I find they can add acoustically very nicely. You simply have to use
any gain incorporated into a design, else things will not add up right..

greg- Hide quoted text -

- Show quoted text -

Greg,

by the way, I was able to find a copy of Part 1 of the papaer you
quoted on the web as well as this related paper:

http://www.diyspeakers.net/Articles/...DAMPING%20FACT...

but I was not able to find the Part 2 that you mentioned.

Can you post a link to Part 2?

I didn't have time to read through it, looks like little more explanation..

http://zekfrivolous.com/sub/usenet/pierce/damp2.txt

greg- Hide quoted text -

- Show quoted text -

ok he is saying again that the output Z of any typical amp these days
is so low compared to the DC resistance of a voice coil that the amp Z
has very little impact on the damping factor of the actual speaker...

and this is true for one speaker or two identical speakers in series..

I agree.

Mark

[Scott Dorsey]

Mark wrote:

ok he is saying again that the output Z of any typical amp these days
is so low compared to the DC resistance of a voice coil that the amp Z
has very little impact on the damping factor of the actual speaker...

and this is true for one speaker or two identical speakers in series..

I'll buy that, but the problem pointed out _wasn't_ a damping issue.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[GregS[_3_]]

In article , (Scott Dorsey) wrote:
Mark wrote:

ok he is saying again that the output Z of any typical amp these days
is so low compared to the DC resistance of a voice coil that the amp Z
has very little impact on the damping factor of the actual speaker...

and this is true for one speaker or two identical speakers in series..

I'll buy that, but the problem pointed out _wasn't_ a damping issue.
--scott

The factor has little effect but it does have effect. When designing a speaker
system one can inject some resistance to get different alignments
from a box, usually needing a larger box as a result. Typically you need
1 ohm or more. I think that generally increases Qes losses or increases Qes and Qts.
I have fulled around with this. I must have had a program to change the
series resistance for the plot. Of course I only wanted the resistance
in the woofer chain.


greg

[Eeyore]

Scott Dorsey wrote:

genericaudioperson wrote:

Is there a common technique for hooking up more than the standard two
speakers to a power amp? If you had a powerful amp, you could run
four speakers. But I'm not sure if you use a simple Y cable, or if
you need a signal conditioning device of some sort to do it properly.

This is discussed in the Yamaha Sound Reinforcement Handbook.

There's a preview on Google Books.
http://books.google.com/books?id=d7f...ement+Handbook

It's a bit slow to load. Don't know how much of it is there either.

Graham

[Eeyore]

Mark wrote:

Really?

I could see this might be true if the speaker coils were like the
windings of a center tapped transformner, but I don't think they are,
they are not magnetically or acousticaly closely coupled to each other
and the winding resistance is high compared to the self coupling of
each coil...

They're ACOUSTICALLY coupled and the manufacturing tolerances mean that 2 units
will have virtually identical impedance curves to the point of no consequence.
Hence both speakers will always see half the input (simplifying it to a 2
speaker series example).

Graham

[GregS[_3_]]

In article , Eeyore wrote:


Mark wrote:

Really?

I could see this might be true if the speaker coils were like the
windings of a center tapped transformner, but I don't think they are,
they are not magnetically or acousticaly closely coupled to each other
and the winding resistance is high compared to the self coupling of
each coil...

They're ACOUSTICALLY coupled and the manufacturing tolerances mean that 2 units
will have virtually identical impedance curves to the point of no consequence.
Hence both speakers will always see half the input (simplifying it to a 2
speaker series example).

When in phase the two in series will play just as loud as one, but
with 1/2 the power. I always like to point this out. At a cost and being bigger,
but a driver will only have 1/4 the power and if done right will never blow out.
Kind of a fail safe, but not what you want necessarily for portable PA. Its also a way
of using cheaper drivers.

greg