70V/100V horn speaker question.

[rg26ce1991@hotmail.com]

Greetings group.
Is it o.k. to use 100v horn speakers with a p.a. that only has a 70v
output terminal?

Altronics sell a lot of 100v speakers, but I do not see any 70v types.

The amplifier has a power rating of 35W.
If 100v speakers can be used, would they only need to be rated at 35W?
Or would the wattage rating of 100v speakers need to be higher because
they are being connected to the 70v output terminal?

Or could the wattage rating of 100v speakers be less than 35w when
connected to the 70v output?


Thanking you,
Russell Griffiths.

 

[Phil Allison]

<rg26ce1991@hotmail.com>wrote

Is it o.k. to use 100v horn speakers with a p.a. that only has a 70v
output terminal?

** Yep - power will be down 50 % though.

Altronics sell a lot of 100v speakers, but I do not see any 70v types.

** All have multi-tapped transformers, just divide the power tapping figures
by 2 for 70 volt operation.

The amplifier has a power rating of 35W.
If 100v speakers can be used, would they only need to be rated at 35W?

** Sure - but then you can only use one.

Or would the wattage rating of 100v speakers need to be higher because
they are being connected to the 70v output terminal?

** Err - the other way around, if at all.

Or could the wattage rating of 100v speakers be less than 35w when
connected to the 70v output?

** Yes - see all those power ratings on the tappings !!

The important thing is the TOTAL power used by all speakers used must not
exceed 35 watts, in your case.




............ Phil

 

[rg26ce1991@hotmail.com]

Thanks for the reply Phil.

I was thinking about 2 c2059 horn speakers from Altronics.
http://www.altronics.com.au/index.asp?area=item&id=C2059

If I understand you right, I can use 2 of these if I set the power
selecter switch on both to 30W.

Because these speakers are 100v, and they will be connected to the 70v
terminal, the power to each speaker will be 15W and not 30W.

Amp rating is 35W.
Total power with both speakers = 30W.


Am I correct?
Or have I misunderstood?

Thanks,
Russell Griffiths.

 

[Phil Allison]

<rg26ce1991@hotmail.com

Thanks for the reply Phil.

I was thinking about 2 c2059 horn speakers from Altronics.
http://www.altronics.com.au/index.asp?area=item&id=C2059

If I understand you right, I can use 2 of these if I set the power
selecter switch on both to 30W.

Because these speakers are 100v, and they will be connected to the 70v
terminal, the power to each speaker will be 15W and not 30W.

Amp rating is 35W.
Total power with both speakers = 30W.


Am I correct?

** Spot on.



.......... Phil

 

[rg26ce1991@hotmail.com]

Thanks Phil.
When using a typical speaker (4ohm, 8ohm etc.), the wattage of the
speaker should be greater than the wattage of the amp.

But if I understand correctly, when using a 100v or 70v speaker, the
wattage should be less than the wattage of the amp.

Is this correct?

Russell Griffiths.

 

[Phil Allison]

<rg26ce1991@hotmail.com

When using a typical speaker (4ohm, 8ohm etc.), the wattage of the
speaker should be greater than the wattage of the amp.

But if I understand correctly, when using a 100v or 70v speaker, the
wattage should be less than the wattage of the amp.

Is this correct?

** Yes.

With line voltage systems, the max drive voltage is known ( 70v or 100v )
and the amp's power rating in watts is known.

Speakers have transformers attached that will allow only so much power to be
absorbed from a given line voltage depending on the tap that is used.

The whole idea is to spread the available amp power across the desired
number of speakers.

So, with a 35 watt amp you can have 7 x 5 watt speakers OR 35 x 1 watt
speakers or any combinatition that adds to no more than 35 watts.

The other really cool thing is that you can use light gauge speaker wire and
run it for long distances with little power loss.




........... Phil

 

[KLR]

On Sat, 30 Jul 2005 00:46:14 +1000, "Phil Allison"
<philallison@tpg.com.au> wrote:

rg26ce1991@hotmail.com


When using a typical speaker (4ohm, 8ohm etc.), the wattage of the
speaker should be greater than the wattage of the amp.

But if I understand correctly, when using a 100v or 70v speaker, the
wattage should be less than the wattage of the amp.

Is this correct?


** Yes.

With line voltage systems, the max drive voltage is known ( 70v or 100v )
and the amp's power rating in watts is known.

Speakers have transformers attached that will allow only so much power to be
absorbed from a given line voltage depending on the tap that is used.

The whole idea is to spread the available amp power across the desired
number of speakers.

So, with a 35 watt amp you can have 7 x 5 watt speakers OR 35 x 1 watt
speakers or any combinatition that adds to no more than 35 watts.

The other really cool thing is that you can use light gauge speaker wire and
run it for long distances with little power loss.


Cheap, common Telephone or cat 5 wire works well for this - even if

the speaker is hundreds of metres away, (I wouldn't try it for 100's
of watts though, but 30w wouldn't be a problem).


I have also had installations in the past where we have had to have
certain individual speakers in a 70v line remotely switched off, and
by putting a SPST switch in one 70v line to the speaker to only cut
one line, the speaker will still have some sound coming out of it
(through leakage to earth back to the amp obviously) so I would
speculate that even running a single wire to the 70v speaker, and
using an earth (terra firma) return (as long as the other side of the
70v line is earthed back at the amp) would probably work if only one
wire was available.

.......... Phil

 

[Phil Allison]

"KLR"

I have also had installations in the past where we have had to have
certain individual speakers in a 70v line remotely switched off, and
by putting a SPST switch in one 70v line to the speaker to only cut
one line, the speaker will still have some sound coming out of it
(through leakage to earth back to the amp obviously) so I would
speculate that even running a single wire to the 70v speaker, and
using an earth (terra firma) return (as long as the other side of the
70v line is earthed back at the amp) would probably work if only one
wire was available.

** Kiddies, do not try this at home.

Electricity is dangerous !!!




............ Phil