Mixer or multiple speakers

[ddoppke]

I'm interested in others opinions when using multiple radios do you find using multiple speakers better or routing them through a mixer to a single speaker? I currently have devices running into a 4 channel mixer/amp (Rolls MA255) output to one set of speakers. I like that I can easily control the volume of either device from a central location. If others have done this I'm curious which way is better for listening quality.

 

[a417]

I'm interested in others opinions when using multiple radios do you find using multiple speakers better or routing them through a mixer to a single speaker? I currently have devices running into a 4 channel mixer/amp (Rolls MA255) output to one set of speakers. I like that I can easily control the volume of either device from a central location. If others have done this I'm curious which way is better for listening quality.

search for "zetron speaker" here, the model 27 comes up a TON.

here's the most recent.

 

[mmckenna]

If others have done this I'm curious which way is better for listening quality.

I don't know what's better for hobby use.
Dispatch centers usually have two speakers:
Select Audio - primary working channel
Unselect Audio - everything else.

The spacial difference between select and unselect audio lets the dispatcher know which source the audio is. The speakers are on separate sides of the console, makes it easy to differentiate.

Again, not sure if that's what a scanner listener would want. In my work truck I've got two radios, one on my 800MHz system, and one multiband on everything else. I put the two speakers in opposite corners of the back of the cab. Easy for my ears to know which radio it is without taking my eyes off the road.

I've heard of some that use mixers using the pan function to float the audio to one side or the other, and allowing mixing some stuff in between. I think that's probably a personal preference.

 

[a417]

It's going to end up being highly individualized opinions about what works for each person.

 

[RFI-EMI-GUY]

I am looking for same solution in my vehicle for multiple radios. Need a 12V audio mixer, balanced input, 4 or more inputs. Considered using a bridge of 70 volt transformers but the isolation to sources might be problem.

 

[mmckenna]

I've used these guys in the past, but most of their stuff is 24volts, if you wanted to deal with that:

Mixing - RDL®

Microphone-level and line-level audio mixers and passive audio divider / combiner products

rdlnet.com

 

[Ubbe]

I am looking for same solution in my vehicle for multiple radios. Need a 12V audio mixer, balanced input, 4 or more inputs. Considered using a bridge of 70 volt transformers but the isolation to sources might be problem.

Use a ground loop isolator for each radio. There's plenty of signal from an external speaker output so no need to use a powered mixer, a passive one are enough if it has a pan function. You can even do your own with a potentiometer with the middle wiper connected to the audio in and the ends of the pot goes to each stereo channel, then you can pan the sound between two speakers. The ground of each ground loop isolators output are tied together and goes to the ground of the aux audio in the car or of a separate external amp.

Either connect to the vehicles aux audio input if you can be without your car stereos radio and music function, or get a cheap 2x10watt amp and two speakers.

Aux input or a separate amp will have some 10k-50k input impedance so if you have 4 radios you use four 50k linear potentiometers in parallel but their wipers goes to each individual radios ground loop isolator. Or get a passive mixer and reconfigure its level pots to instead be pan pots to work as explained earlier. There are some small pan controller modules that also could be used.

Ground loop isolators are usually stereo but if they use one 3,5mm stereo plug for inputs they use a common ground and some with RCA connectors also have a common ground, although inside it is two separate isolation transformers but will require some circuit board modifications to separate their grounds to be able to be used with two radios if their speaker outputs do not use ground.

You can have the balance/pan module hidden once it has been set to your preference and have a passive mixer between ground loop and pan controller as the level control and have it more easily accessible to quickly be able to adjust sound levels from each radio.

There are USB powered mixers that have everything needed but are not so easy to use in a vehicle.

/Ubbe

 

[RFI-EMI-GUY]

Use a ground loop isolator for each radio. There's plenty of signal from an external speaker output so no need to use a powered mixer, a passive one are enough if it has a pan function. You can even do your own with a potentiometer with the middle wiper connected to the audio in and the ends of the pot goes to each stereo channel, then you can pan the sound between two speakers. The ground of each ground loop isolators output are tied together and goes to the ground of the aux audio in the car or of a separate external amp.

Either connect to the vehicles aux audio input if you can be without your car stereos radio and music function, or get a cheap 2x10watt amp and two speakers.

Aux input or a separate amp will have some 10k-50k input impedance so if you have 4 radios you use four 50k linear potentiometers in parallel but their wipers goes to each individual radios ground loop isolator. Or get a passive mixer and reconfigure its level pots to instead be pan pots to work as explained earlier. There are some small pan controller modules that also could be used.

Ground loop isolators are usually stereo but if they use one 3,5mm stereo plug for inputs they use a common ground and some with RCA connectors also have a common ground, although inside it is two separate isolation transformers but will require some circuit board modifications to separate their grounds to be able to be used with two radios if their speaker outputs do not use ground.

You can have the balance/pan module hidden once it has been set to your preference and have a passive mixer between ground loop and pan controller as the level control and have it more easily accessible to quickly be able to adjust sound levels from each radio.

There are USB powered mixers that have everything needed but are not so easy to use in a vehicle.

/Ubbe

Stereo spatial monitoring would be an ideal solution and would provide redundancy. I would need at minimum a 4 channel stereo mixer with balance controls for each input.

 

[RFI-EMI-GUY]

I've used these guys in the past, but most of their stuff is 24volts, if you wanted to deal with that:

Mixing - RDL®

Microphone-level and line-level audio mixers and passive audio divider / combiner products

rdlnet.com

They have one that has transformer balancing. a 12V to 24V convertor would be needed. Nice packaging.

 

[mmckenna]

They have one that has transformer balancing. a 12V to 24V convertor would be needed. Nice packaging.

Back before our fire department merged, we had a few VHF radios, one for monitoring local agencies, one for tone out. They were mixed into one amplifier input using one of their mixers. Simple solution that was reliable. As far as I know, it's still running.

 

[majoco]

I use a Behringer RX 1602 - each input has a level and balance control and the output has a monitor and stereo out to a small 15 watt amplifier and two speakers - works very well - maybe too complicated for a truck though.

 

[RFI-EMI-GUY]

This looks promising. Has balanced inputs and outputs. Has "PAN" adjustments for each input so that you can set stage position of each mono input with respect to stereo outputs. Requires 12-15VDC. The DC coaxial plug polarity is backwards so careful there. Use with two amplified speakers. Hoping the inputs are transformer coupled as there could be DC transients from various radios. (mobile environment)

https://rolls.com/doc/manuals/manual_MX-401.pdf

 

[Ubbe]

Yes, that one has everything, and hopefully including ground loop isolating transformers, but I would open it up and look inside for 6 small transformers. Just connect to pin 2 and 3 in the XLR connector and use the 3,5mm stereo out to connect to aux in the vehicle or separate amplifiers. It's plug and play and small enough to have in a vehicle. A bit strange that they have the polarity switched on the DC connector so that the sleeve of the connector plug will have 12V and can easily shortcircuit to any metal in the vehicle. I would rewire that inside the box to a standard configuration that scanners are using.

It's designed for mic levels up to 10mV signal but the line in level it can be swithced to are 0,7V but then it might not use the 600 ohm isolating transformers.

https://www.amazon.com/Rolls-MX401-4-channel-Stereo-Mixer/dp/B0CBL9X7P2

/Ubbe

 

[N8YX]

For shack use I have a pair of NCS-3230s. The secondary analog rigs in the setup (Icom R-7000s) feed one while the various Bearcat BC trunking-capable scanners feed the other. Each has a DSP-599xz connected to the In/Out jacks on the rear panel and each feeds to its own Denon digital audio recorder.

I'd like to find one more of each piece OR an 8-16ch mixer/amp that supports a Master Mute control line or function button.

 

[Ubbe]

I'd like to find one more of each piece OR an 8-16ch mixer/amp that supports a Master Mute control line or function button.

Look for a Solo button on each channel. When that are pushed it will mute all other channels. You pull down the level on that channel to zero or use a channel that has no input signal if you need it to go totally quiet. There are software mixers, I believe free or for a few dollars shareware, that runs on your PC and you use those small $10 USB stereo audio interfaces to get as many channels as needed.

There are companies that sell refurbished mini computers, like half a keyboard in size, and I got a HP with Win10 for $80. I use it with bluetooth keyboard and mice. I can power off my main computer and have that mini to handle surveillance cameras and any other applications that needs to run uninterrupted.

/Ubbe

 

[krokus]

I'm interested in others opinions when using multiple radios do you find using multiple speakers better or routing them through a mixer to a single speaker? I currently have devices running into a 4 channel mixer/amp (Rolls MA255) output to one set of speakers. I like that I can easily control the volume of either device from a central location. If others have done this I'm curious which way is better for listening quality.

I like having separated speakers, so you can differentiate between sources. That also helps isolate the conversations, so you can better track multiple inputs.

In a previous vehicle, I had a CB on the passenger side of the transmission hump, using the internal speaker. My dual-band ham had the 2m speaker between the driver's seat and the driver's B post, and the 70cm speaker between the passenger seat and passenger side B post. The scanner speaker was between the driver's seat and transmission hump.