So...we have a brand spanking new QSC 3002 (3000 Watt, bi channel amp)
intended to power 4 500w speakers each running with an impedance of 2
ohms. Only thing is that the amp doesnt advise powering a comibned load
of 2 ohms. I really want to be able to use all 3000 watts for this
cluster of speakers which i could do if i could bring the impedance
down to a total of 4 ohms. problem is i dont know how i can do that.
Does anyone have any ideas?

Thanks

M

So...we have a brand spanking new QSC 3002 (3000 Watt, bi channel amp)
intended to power 4 500w speakers each running with an impedance of 2
ohms.


** So each 500 watt speaker box is 2 ohms ????

2 ohm boxes are rare things.


Only thing is that the amp doesnt advise powering a comibned load
of 2 ohms.


** Gobbledegook.

What is being "combined" ?

Do you actually mean bridge mode ?


I really want to be able to use all 3000 watts for this
cluster of speakers which i could do if i could bring the impedance
down to a total of 4 ohms. problem is i dont know how i can do that.
Does anyone have any ideas?


** Do you ?



......... Phil

On 2 May 2006 03:28:15 -0700, wrote:

So...we have a brand spanking new QSC 3002 (3000 Watt, bi channel amp)
intended to power 4 500w speakers each running with an impedance of 2
ohms. Only thing is that the amp doesnt advise powering a comibned load
of 2 ohms. I really want to be able to use all 3000 watts for this
cluster of speakers which i could do if i could bring the impedance
down to a total of 4 ohms. problem is i dont know how i can do that.
Does anyone have any ideas?

Thanks

M

Your options are 0.5, 2 and 8 ohms. Nothing else. Sorry.

Your only other option is to spend money on a transformer - probably
quite a bit more than you spent on the amp.

d

--
Pearce Consulting
http://www.pearce.uk.com

yep we are talking about bridge mode. The speakers impedance are 8 ohms
each. The amp doesnt advise a combined load of 2ohms or less...i think
thats fairly straightforward - combined means putting multiple speakers
together either in series or parrallel.

On 2 May 2006 03:41:30 -0700, wrote:

yep we are talking about bridge mode. The speakers impedance are 8 ohms
each. The amp doesnt advise a combined load of 2ohms or less...i think
thats fairly straightforward - combined means putting multiple speakers
together either in series or parallel.

No, you can't reach 4 ohms with these speakers. If they are 8 ohms
each, you can have 2, 8 or 32. Unless, that is, you are willing to run
them with different amounts of power to each. Put two in parallel for
four ohms, then the other two in series for 16 ohms. Finally put those
two combinations in parallel for a total of 3.2 ohms.

If you are putting all four in one box as a vertical line, you can
actually make a decent radiation pattern this way. Put the two higher
powered (parallel) units in the centre of the line, and the lower
powered series pair at the ends.

d

--
Pearce Consulting
http://www.pearce.uk.com

** Please post properly for usenet.

Click on "options" NOT reply.

Quote some text and leave the name of the other poster VISIBLE!


yep we are talking about bridge mode.


** Shame you did not say so.


The speakers impedance are 8 ohms
each.


** Shame you previously suggested they were 2 ohms each.


The amp doesnt advise a combined load of 2ohms or less.


** WRONG !!!

The PLX 3002 does not run a load of less than 4 ohms in bridge mode.

Even then there are serious qualifications involved.

READ the spec sheet !!



...i think

** No you don't.


thats fairly straightforward - combined means putting multiple speakers
together either in series or parrallel.


** Yawn ......

Just wire a pair of 8 ohm boxes to each channel.

The amp will give almost 1000 watts /ch into 4 ohms.




........ Phil

hmm, will give it a try but the qsc people dont recommend loads of less
than 4 ohms and besides this amp is just powering the front cluster (in
a horizontal line as you suggest) and has satellites on the side anyway.

On 2 May 2006 04:11:02 -0700, wrote:

hmm, will give it a try but the qsc people dont recommend loads of less
than 4 ohms and besides this amp is just powering the front cluster (in
a horizontal line as you suggest) and has satellites on the side anyway.

A vertical line - *never* a horizontal line.

d

--
Pearce Consulting
http://www.pearce.uk.com

yep yr quite right, my mistake, i did incorectly suggest the boxs were
2 ohms each, and yr right about the 3002, the lower limit is, as i
posted later 4 ohms. The point is im trying to get more than 500 watts
per channel.

** HEY ASSHOLE

I SEE YOU HAVE REAL TROUBLE READING

Post properly for usenet.

Click on "options" NOT reply.

Quote some text and leave the name of the other poster VISIBLE !


----------------------------------------------------------------------

yep yr quite right, my mistake, i did incorectly suggest the boxs were
2 ohms each, and yr right about the 3002, the lower limit is, as i
posted later 4 ohms. The point is im trying to get more than 500 watts
per channel.

-----------------------------------------------------------------------


** The PLX 3002 spec sheet indicates over 900 watts rms with 4 ohms per
channel, both driven.

Stop being a PITA.

Take advice.



........ Phil

Phil Allison wrote:


Dude,
Chill out man. Im sorry for not using the correct etiquette - im lazy.
If it bugs you noone is forcing you to hang around on this thread. Ill
make an effort but there is really no need to be such a dumb kid about
it.

Grow up a bit.

M

hmm, will give it a try but the qsc people dont recommend loads of less
than 4 ohms and besides this amp is just powering the front cluster (in
a horizontal line as you suggest) and has satellites on the side anyway.

Wire the four 8-ohm speakers in series-parallel -- you'll still have an
8-ohm load.

wrote:
yep yr quite right, my mistake, i did incorectly suggest the boxs were
2 ohms each, and yr right about the 3002, the lower limit is, as i
posted later 4 ohms. The point is im trying to get more than 500 watts
per channel.

Will the speakers take it?

There's an optimum impedance for the speaker for maximum power transfer
from the amplifier. It's not the "matched" impedance (connecting an 8
ohm speaker to an 8 ohm output), it's related to the maximum current
and voltage output of the amplifier. There is probably a table of
values in the manual for the available power at various loads.

When operating in the bridge mode, you're putting the output stages in
series so the minimum load impedance will be higher - you get more
voltage but no more current. That's why each channel can drive a 2 ohm
load but it isn't recommended with the bridged arrangement.

You may need to use different speakers, or perhaps more speakers, to
get the full power capability of the amplifier into the load. And when
you do, remember that all of that power has to come from somewhere.
Don't plug it into a wimpy AC circuit.

wrote in message
oups.com...


Dude,
Chill out man.


** **** off - imbecile.


Im sorry for not using the correct etiquette - im lazy.


** **** off - GG imbecile.


If it bugs you noone is forcing you to hang around on this thread.


** **** off - GG imbecile.

Ill make an effort but there is really no need to be such a dumb kid about
it.

Grow up a bit.


** **** off - GG imbecile.

Don't come back.



......... Phil

In article .com,
wrote:
So...we have a brand spanking new QSC 3002 (3000 Watt, bi channel amp)
intended to power 4 500w speakers each running with an impedance of 2
ohms. Only thing is that the amp doesnt advise powering a comibned load
of 2 ohms. I really want to be able to use all 3000 watts for this
cluster of speakers which i could do if i could bring the impedance
down to a total of 4 ohms. problem is i dont know how i can do that.
Does anyone have any ideas?

I am assuming the speakers are each eight ohms?

Parallel two speakers to each channel. Each channel now sees a four
ohm load, so it's happy.

If the speakers themselves are four ohms each, you COULD run them in
series. to give you eight ohms per channel. In general, this is a
bad idea because you now have a weird varying impedance (the other speaker)
in series with your speaker loads.

If you have had any thoughts about bridged mono, don't.
--scott


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

wrote:
yep we are talking about bridge mode. The speakers impedance are 8 ohms
each. The amp doesnt advise a combined load of 2ohms or less...i think
thats fairly straightforward - combined means putting multiple speakers
together either in series or parrallel.


Bridged mode is NOT appropriate for low impedance loads. Bridged mode
doubles the VOLTAGE the amplifier can put out, but it does not increase
the CURRENT at all. This means the effective output impedance of the
amp is raised, not lowered.

Run two speakers on each side, and drive both sides with the same mono
signal.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

wrote:

yep we are talking about bridge mode. The speakers impedance are 8 ohms
each. The amp doesnt advise a combined load of 2ohms or less...I think
thats fairly straightforward - combined means putting multiple speakers
together either in series or parrallel.

Actually in bridged mode QSC state the load should be *4* ohm minimum.

Wire them as 8 ohms.

Actually it amkes more sense to run the amp in mom mode and run 2 cabs off
each channel. It'll do the same.

Graham

Pooh Bear wrote:

wrote:

yep we are talking about bridge mode. The speakers impedance are 8 ohms
each. The amp doesnt advise a combined load of 2ohms or less...I think
thats fairly straightforward - combined means putting multiple speakers
together either in series or parrallel.


typo correction


Actually it makes more sense to run the amp in mono mode and run 2 cabs off
each channel. It'll do the same.

Graham

wrote:

yep yr quite right, my mistake, i did incorectly suggest the boxs were
2 ohms each, and yr right about the 3002, the lower limit is, as i
posted later 4 ohms. The point is im trying to get more than 500 watts
per channel.

The ear is sensitive to volume in a logarithmic law.

500 watts doesn't for example sound twice as loud as 250watts, so don't
fret over not getting every single watt you think you might be able to
screw out of the amplifier. Reliability is *way* more important.

Graham

"Mike Rivers"
wrote:
yep yr quite right, my mistake, i did incorectly suggest the boxs were
2 ohms each, and yr right about the 3002, the lower limit is, as i
posted later 4 ohms. The point is im trying to get more than 500 watts
per channel.

Will the speakers take it?

There's an optimum impedance for the speaker for maximum power transfer
from the amplifier. It's not the "matched" impedance (connecting an 8
ohm speaker to an 8 ohm output), it's related to the maximum current
and voltage output of the amplifier. There is probably a table of
values in the manual for the available power at various loads.

When operating in the bridge mode, you're putting the output stages in
series so the minimum load impedance will be higher - you get more
voltage but no more current. That's why each channel can drive a 2 ohm
load but it isn't recommended with the bridged arrangement.

You may need to use different speakers, or perhaps more speakers, to
get the full power capability of the amplifier into the load. And when
you do, remember that all of that power has to come from somewhere.
Don't plug it into a wimpy AC circuit.



* Check this poster's IP address: 196.192.102.87

Seems he is posting from Mauritius.

An island so tiny it does not appear in my school atlas.

Might be hard to find an AC circuit that ain't "wimpy".





......... Phil

wrote:

Phil Allison wrote:


Dude,
Chill out man. Im sorry for not using the correct etiquette - im lazy.

Yeah, you didn't read the spec before buying the amp !

Graham

Scott Dorsey wrote:

wrote:
yep we are talking about bridge mode. The speakers impedance are 8 ohms
each. The amp doesnt advise a combined load of 2ohms or less...i think
thats fairly straightforward - combined means putting multiple speakers
together either in series or parrallel.

Bridged mode is NOT appropriate for low impedance loads. Bridged mode
doubles the VOLTAGE the amplifier can put out, but it does not increase
the CURRENT at all. This means the effective output impedance of the
amp is raised, not lowered.

The kids these days have just heard that bridged gives more power.

It's not cool to think either.

Graham

wrote:
So...we have a brand spanking new QSC 3002 (3000 Watt, bi channel amp)
intended to power 4 500w speakers each running with an impedance of 2
ohms. Only thing is that the amp doesnt advise powering a comibned load
of 2 ohms. I really want to be able to use all 3000 watts for this
cluster of speakers which i could do if i could bring the impedance
down to a total of 4 ohms. problem is i dont know how i can do that.
Does anyone have any ideas?

Thanks

M


A lot of people have given you advice...most of it good (the technical
part, anyway)

To reiterate the consensus: your best option--in my opinion and in the
opinions of those in here who matter--is to tie the inputs of both
channels together and run two boxes in parallel off each channel. Do
NOT use the mono bridge mode switch (if it exists) to tie the inputs
together. That will put one channel out of phase with the other (You
can remedy this by putting one *output* out of phase, but it makes
things--IMO--unnecessarily complicated given your demonstrated technical
skill level. Use a 'Y' cord at the input.)

Got it?

Wire in series. Ohms will add together.
Max Arwood

"jakdedert" wrote in message
...
wrote:
So...we have a brand spanking new QSC 3002 (3000 Watt, bi channel amp)
intended to power 4 500w speakers each running with an impedance of 2
ohms. Only thing is that the amp doesnt advise powering a comibned load
of 2 ohms. I really want to be able to use all 3000 watts for this
cluster of speakers which i could do if i could bring the impedance
down to a total of 4 ohms. problem is i dont know how i can do that.
Does anyone have any ideas?

Thanks

M


A lot of people have given you advice...most of it good (the technical
part, anyway)

To reiterate the consensus: your best option--in my opinion and in the
opinions of those in here who matter--is to tie the inputs of both
channels together and run two boxes in parallel off each channel. Do NOT
use the mono bridge mode switch (if it exists) to tie the inputs together.
That will put one channel out of phase with the other (You can remedy this
by putting one *output* out of phase, but it makes
things--IMO--unnecessarily complicated given your demonstrated technical
skill level. Use a 'Y' cord at the input.)

Got it?

tie the inputs of both channels together and run two boxes in parallel off each channel

A good suggestion. Effective, simple, powerful, etc.

Use a 'Y' cord at the input.)

The amp the OP is using has DIP switches that allow one to select
"Parallel Input" - what goes into input A will feed directly into input
B - Easy as pie, and effective.

Mineapollo - follow this suggestion and move on. Ignore the netiquette
nazis... you'll be fine.

Corey

coreybenson wrote:
tie the inputs of both channels together and run two boxes in parallel off each channel

A good suggestion. Effective, simple, powerful, etc.

Use a 'Y' cord at the input.)

The amp the OP is using has DIP switches that allow one to select
"Parallel Input" - what goes into input A will feed directly into input
B - Easy as pie, and effective.

I'll accept that...as long as the OP understands the distinction...and
the procedure.

Mineapollo - follow this suggestion and move on. Ignore the netiquette
nazis... you'll be fine.

Seconded.

jak
Corey

wrote in message
oups.com...
yep we are talking about bridge mode. The speakers impedance are 8 ohms
each. The amp doesnt advise a combined load of 2ohms or less...i think
thats fairly straightforward - combined means putting multiple speakers
together either in series or parrallel.

Un-bridge the amplifier; drive two speakers (in parallel) from each channel,
and connect the inputs in parallel. You'll be driving each channel into 4
ohms which will get you lots and lots and lots of power.

Peace,
Paul

Paul Stamler wrote:

wrote in message
oups.com...
yep we are talking about bridge mode. The speakers impedance are 8 ohms
each. The amp doesnt advise a combined load of 2ohms or less...i think
thats fairly straightforward - combined means putting multiple speakers
together either in series or parrallel.

Un-bridge the amplifier; drive two speakers (in parallel) from each channel,
and connect the inputs in parallel. You'll be driving each channel into 4
ohms which will get you lots and lots and lots of power.

I agree with the most simple, straightforward approach here.
Bridging unneccesarily complicates things. Just remember to
use good heavy (12G or better) cables and run everything in
phase.

rd

Pooh Bear wrote:

Yeah, you didn't read the spec before buying the amp !

Graham

Actually i didnt buy the amp. But thanks for yr comments helps a lot.
Guess
we'll leave it in parallel mode with 500w per speaker then and stop
trying to squeeze ounces of power out.


Cheers

M

Poopie Bear wrote:

Yeah, you didn't read the spec before buying the amp !


Actually i didnt buy the amp. But thanks for yr comments helps a lot.
Guess
we'll leave it in parallel mode with 500w per speaker then and stop
trying to squeeze ounces of power out.



** Pray it never breaks down too.

PLX amps are full SMD, one PCB nightmares.





........ Phil

RD Jones wrote:
Paul Stamler wrote:

Un-bridge the amplifier; drive two speakers (in parallel) from each channel,
and connect the inputs in parallel. You'll be driving each channel into 4
ohms which will get you lots and lots and lots of power.

I agree with the most simple, straightforward approach here.
Bridging unneccesarily complicates things. Just remember to
use good heavy (12G or better) cables and run everything in
phase.

rd

righty ho.
Cheers

Marc

wrote:

Pooh Bear wrote:

Yeah, you didn't read the spec before buying the amp !

Graham

Actually i didnt buy the amp. But thanks for yr comments helps a lot.
Guess we'll leave it in parallel mode with 500w per speaker then and
stop
trying to squeeze ounces of power out.

By far the best solution.

Graham

On 2 May 2006 22:46:17 -0700, wrote:


RD Jones wrote:
Paul Stamler wrote:

Un-bridge the amplifier; drive two speakers (in parallel) from each channel,
and connect the inputs in parallel. You'll be driving each channel into 4
ohms which will get you lots and lots and lots of power.

I agree with the most simple, straightforward approach here.
Bridging unneccesarily complicates things. Just remember to
use good heavy (12G or better) cables and run everything in
phase.

rd

righty ho.
Cheers

Marc

Right. Do it this way!

wrote:
Pooh Bear wrote:

Yeah, you didn't read the spec before buying the amp !

Graham

Actually i didnt buy the amp. But thanks for yr comments helps a lot.
Guess
we'll leave it in parallel mode with 500w per speaker then and stop
trying to squeeze ounces of power out.


Cheers

M


I don't know about this amp specifically, but on most the bridged output
is simply the sum of the two channels at twice the impedance (ie 200 wpc
stereo @ 4 ohms or 400 watts bridged @ 8 ohms).

So...you're not really losing any power, but gaining simplicity.

jak