Batboard

I am looking to install two speakers off of one W4 Spectra radio head. Think split cab on a fire truck.
Motorola says it can't, (or shouldn't) be done. Their answer, of course is dual head option at $750 or so.
Does anyone know how to do this? I am running two (8 Ohm factory speakers) now in series with little issue. Haven't lost much volume. Am I damaging the Audio PA?
I tried them in parallel but it raised the radios current draw which scared me.
Is there any way to use amplified, or 12 Volt powered speakers? Someone suggested the HSN1000 speakers from the XTVA kits are 12 Volt powered.
Any suggestions are greatly appreciated.

Wiring two 8-ohm speakers in parallel makes the circuit's resistance about 4 ohms, which allows more current to flow. Wiring them in series, as you have done, has the exact opposite effect.
Yes you can use powered speakers but odds are they will require almost as much power to drive them as you're now providing directly to the speakers. If you change from paper-cone speakers to small, 8-ohm, horn/trumpet speakers you probably would get somewhat louder results without the bother and expense of adding powered speakers.

You can use two 8 ohm speakers in parallel which is 4 ohms. The Spectra audio amp will drive the two speakers just fine and save you a lot of money too!

Yes the Spectra radio will draw a little more current with the two speakers in parallel. About 3 amps at normal volume.

You done good patriot. I don't have a problem with what you did.

If he is is uisng a remote setup wouldn't it be better to install the second speaker from the accessory port instead of loading the speaker output at the head?

I've done this on one radio they use on the flightline. Needed an external speaker while they were outside working on the runway lights.

misawatech wrote:If he is is uisng a remote setup wouldn't it be better to install the second speaker from the accessory port instead of loading the speaker output at the head?

I've done this on one radio they use on the flightline. Needed an external speaker while they were outside working on the runway lights.

Yes, That is a good way to do the second speaker.

patriots1 wrote:I am looking to install two speakers off of one W4 Spectra radio head. Think split cab on a fire truck.
Motorola says it can't, (or shouldn't) be done. Their answer, of course is dual head option at $750 or so.
Does anyone know how to do this? I am running two (8 Ohm factory speakers) now in series with little issue. Haven't lost much volume. Am I damaging the Audio PA?
I tried them in parallel but it raised the radios current draw which scared me.
Is there any way to use amplified, or 12 Volt powered speakers? Someone suggested the HSN1000 speakers from the XTVA kits are 12 Volt powered.
Any suggestions are greatly appreciated.

Moto is full of S***, the second head does not add a second audio amp on the Astro Spectras.

Jim

n7maq wrote: Moto is full of S***, the second head does not add a second audio amp on the Astro Spectras.

Jim

Jim,

I thought (and maybe it is an option only with a handset) that the second speaker have it's own volume control and is amplified. So technically, the second speaker would then have it's own amplifier. It won't be in the radio, but....

Maybe I am thinking MCS.

-Alex