Hi,
I'm setting up a parallel configuration of 23 sets of Sony SRS-A205
active speakers in work to be fed from a streaming radio feed from a
PC. The input impedence of the amp in each active speaker is 4.7kOhms
(at 1Khz). The speaker wire runs approx 400 meters in total. I gather
that I don't need a substantial power amp between the PC and the
speakers considering the speakers have amps present within the speaker
boxes, but do I need any kind of amplification function between the PC
audio out and the collection of active speakers or will the PC sound
card be able to handle sending adequate signal levels to the 23 sets of
active speakers over the 400 meters of speaker cable. The speaker
cable is ordinary # 16 gauge multistranded. Any ideas would be
appreciated. Anybody know the maths to solve this question?

Chris.

wrote in message
oups.com...
Hi,


** Google Groper .........

I'm setting up a parallel configuration of 23 sets of Sony SRS-A205
active speakers in work to be fed from a streaming radio feed from a
PC. The input impedence of the amp in each active speaker is 4.7kOhms
(at 1Khz). The speaker wire runs approx 400 meters in total.


** Huh - why "speaker wire".

Audio signals need to use shielded cable.



I gather
that I don't need a substantial power amp between the PC and the
speakers considering the speakers have amps present within the speaker
boxes, but do I need any kind of amplification function between the PC
audio out and the collection of active speakers or will the PC sound
card be able to handle sending adequate signal levels to the 23 sets of
active speakers over the 400 meters of speaker cable.


** Using unshielded "speaker cable " is a bad idea.

It will pick up hum, bussing noises from fluoros, mobile phone buzz, radio
signals etc GALORE.


The speaker
cable is ordinary # 16 gauge multistranded.


** Is this cable already installed ???

Do you have no option but to utilise it ?

There is a slightly expensive way if you must.





........ Phil

Phil,
Its is indeed shielded wire, I forgot to include it in the post. Do you
know if I need to include a power amp of any sort, in the setup between
a PC streaming an audio signal to the 23 sets of active speakers in
parallel? Any advise would be appreciated.

Chris.

wrote in message
oups.com...

** Google Groper .........

No context - no reply name visible .....


Its is indeed shielded wire,


** Then describe it PROPERLY !!!!

Has it one core or two ?

What sort of cable is it?

Is it already installed or not ?

If so - what was the purpose.





....... Phil

In article .com,
wrote:
I'm setting up a parallel configuration of 23 sets of Sony SRS-A205
active speakers in work to be fed from a streaming radio feed from a
PC. The input impedence of the amp in each active speaker is 4.7kOhms
(at 1Khz). The speaker wire runs approx 400 meters in total. I gather
that I don't need a substantial power amp between the PC and the
speakers considering the speakers have amps present within the speaker
boxes, but do I need any kind of amplification function between the PC
audio out and the collection of active speakers or will the PC sound
card be able to handle sending adequate signal levels to the 23 sets of
active speakers over the 400 meters of speaker cable. The speaker
cable is ordinary # 16 gauge multistranded. Any ideas would be
appreciated. Anybody know the maths to solve this question?

Long low level unbalanced runs might cause you problems, depending on the
environment. However, if you want to try it you need a DA with a low
output impedance to feed all those rather low impedance inputs. Something
like the TDA2822M chip should do. It's stereo, so fine if your system is
too, or could have its inputs paralleled and the outputs driving half the
number of speakers each. Use a 9 volt supply and terminate the outputs at
8 ohms using 2 watt resistors.

Personally, I'd use a balanced distribution system.

--
*Cover me. I'm changing lanes.

Dave Plowman London SW
To e-mail, change noise into sound.

"Owain"


(2) It is likely in a work scenario with this sort of distance that you
premises have 3-phase electricity (415V between phases) and you would be
supplying different sets of speakers from different phases. This has
electrical safety implications.


** Absolute bunkum.

All 3 phases have a common neutral which is linked to ground at the distro.



(3) Unscreed untwisted cable is unsuitable for line-level audio
distribution at these distances.


** Not if properly transformer balanced at the drive end and each take off
point.

Running the audio line at a level of say 10 volts would help a lot too.




........ Phil

On Tue, 23 May 2006 23:19:19 +0100, wrote:

Hi,
I'm setting up a parallel configuration of 23 sets of Sony SRS-A205
active speakers in work to be fed from a streaming radio feed from a
PC. The input impedence of the amp in each active speaker is 4.7kOhms
(at 1Khz). The speaker wire runs approx 400 meters in total. I gather
that I don't need a substantial power amp between the PC and the
speakers considering the speakers have amps present within the speaker
boxes, but do I need any kind of amplification function between the PC
audio out and the collection of active speakers or will the PC sound
card be able to handle sending adequate signal levels to the 23 sets of
active speakers over the 400 meters of speaker cable. The speaker
cable is ordinary # 16 gauge multistranded. Any ideas would be
appreciated. Anybody know the maths to solve this question?

Chris.


Looks like no-one has really answered the question although Dave gave you
a big clue when he mentioned DA. DA stands for distribution amplifier
which takes your output from the soundcard and buffers it into a number of
outputs suitable for sending to your active speakers. People like Drawmer
and Sonifex make them.

You can usually get away with paralleling 2 or 3 inputs together and
feeding them from a single output if the connections are short but you
probably need a dedicated DA output for each speaker with a long cable.

Cheers

James.

"James Perrett"
:



Looks like no-one has really answered the question


** That would be because the OP has done a runner and refused to supply
relevant details.

That would be because the cretyn was yet another lying troll.

( snip rest of your irrelevant drivel )




......... Phil