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Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => Installed Sound/Contracting => Topic started by: Michael J Forbes on May 29, 2014, 05:03:26 AM

Title: speaker zoning via relays
Post by: Michael J Forbes on May 29, 2014, 05:03:26 AM
Hi im designing a complex system, although the sound side of things is uncomplicated, however its only a single zone amp and i wish to split the classroom into two areas in respect of the ceiling speakers (100v), -the system will have a central controller and touchpanel- i have four spkrs in the main area which will more or less be active all the time, there are a further two speakers that i wish to isolate, can i run a feed from the last of the four into the relay port of the central controller then program the system to close the relay thus activating the isolated two speakers, if this is the way to go...... do i have to make it all in series? or (saving cable runs here...) can i run a separate feed to the relay and have in effect 4 speakers in series with a further 2 in parallel switched via relay?

Hope im making sense ppl!!

Thanks for looking.

M
Title: Re: speaker zoning via relays
Post by: Ray Aberle on May 29, 2014, 09:49:39 AM
Hi im designing a complex system, although the sound side of things is uncomplicated, however its only a single zone amp and i wish to split the classroom into two areas in respect of the ceiling speakers (100v), -the system will have a central controller and touchpanel- i have four spkrs in the main area which will more or less be active all the time, there are a further two speakers that i wish to isolate, can i run a feed from the last of the four into the relay port of the central controller then program the system to close the relay thus activating the isolated two speakers, if this is the way to go...... do i have to make it all in series? or (saving cable runs here...) can i run a separate feed to the relay and have in effect 4 speakers in series with a further 2 in parallel switched via relay?

Hope im making sense ppl!!

Thanks for looking.

M

Hi, "M," first of all, please pop into your profile and change your Display Name to reflect your full first and last name. Unfortunately, we're not permitted to assist you until you do!

Thanks,

Ray Aberle
Title: Re: speaker zoning via relays
Post by: Ivan Beaver on May 29, 2014, 12:45:57 PM
Hi im designing a complex system, although the sound side of things is uncomplicated, however its only a single zone amp and i wish to split the classroom into two areas in respect of the ceiling speakers (100v), -the system will have a central controller and touchpanel- i have four spkrs in the main area which will more or less be active all the time, there are a further two speakers that i wish to isolate, can i run a feed from the last of the four into the relay port of the central controller then program the system to close the relay thus activating the isolated two speakers, if this is the way to go...... do i have to make it all in series? or (saving cable runs here...) can i run a separate feed to the relay and have in effect 4 speakers in series with a further 2 in parallel switched via relay?

Hope im making sense ppl!!

Thanks for looking.

M
Why are you wanting to run the speakers in series-that is THE HARD AND COMPLICATED way to do it-lot so room for polarity issues and so forth.

Since you are running 100V line (I assume you are licensed to run HIGH voltage?) parallel is the simplest and least complicated way.

The actual wiring will depend on the wattages you are looking at and so forth.

If it were me-I would run the main speakers all in parallel then to a relay (it could be remotely located) use a low voltage (12 or 24V) to trigger it and put the other speakers in parallel with the first ones.

Why make it more complicated than it has to be.
Title: Re: speaker zoning via relays
Post by: Hal Bissinger/COMSYSTEC on May 30, 2014, 08:42:13 AM
Since you are running 100V line (I assume you are licensed to run HIGH voltage?) parallel is the simplest and least complicated way.

If you are using a constant voltage system (100v), series connection of speakers with line transformers to the 100v line is not done. But I don't think that's what you are saying. What I think you are asking is if you can extend the line feeding the four speakers that are "always on" to the controller then to the remaining two "switched" speakers rather than run a separate "home run" back to the amp? Sure. The only thing I would suggest is that your controller switch both sides of the line (DPST contacts) not just one (SPST).

-Hal
Title: Re: speaker zoning via relays
Post by: Frank Koenig on June 03, 2014, 01:37:01 PM
One three occasions I've tried to use relays to switch speaker-level audio and all ended in disappointment when the contact resistance went up over time. Aware of this, the third time, I went through some effort to select a relay with gold plated contacts, low specified initial resistance, and a 5A current rating. It still had problems after a while.

I guess speaker audio falls in a middle ground where the current is high enough to require a "power" relay but not high enough to weld the contacts on each closure, which is how power relays achieve low on-resistance. Maybe there's a good relay out there (can't get the Hg-wetted ones anymore), but I haven't found it. I stay away from relays now.

--Frank
Title: Re: speaker zoning via relays
Post by: Hal Bissinger/COMSYSTEC on June 03, 2014, 06:54:06 PM
One three occasions I've tried to use relays to switch speaker-level audio and all ended in disappointment when the contact resistance went up over time.

Shouldn't cause a problem with a 100v system. Low current/high voltage.

-Hal
Title: Re: speaker zoning via relays
Post by: Ivan Beaver on June 04, 2014, 07:34:36 AM
One three occasions I've tried to use relays to switch speaker-level audio and all ended in disappointment when the contact resistance went up over time. Aware of this, the third time, I went through some effort to select a relay with gold plated contacts, low specified initial resistance, and a 5A current rating. It still had problems after a while.

I guess speaker audio falls in a middle ground where the current is high enough to require a "power" relay but not high enough to weld the contacts on each closure, which is how power relays achieve low on-resistance. Maybe there's a good relay out there (can't get the Hg-wetted ones anymore), but I haven't found it. I stay away from relays now.

--Frank
I like to use 30A for switching speaker levels.

It also depends on "how/when" the relay is used.

If you are switching while there is signal on the line there could be some arcing.  But is switched when no signal is present-there should be no arcing.