Help with putting 3.5mm plug to MOTO speakers

[LFN]

Hi. Is it possible to damage something when you´re mounting a 3.5mm plug to un-amplified Motorola speakers if you don´t know how to solder the wires correct on to the new 3,5mm scannerplug?
I don´t know which cable is positive and negative.
How do I know if it´s correct?
Is the speaker quiet with the cables wrong way or what? (sorry for my bad English)

 

[CCHLLM]

Your English is better than most of us here. Audio isn't really "positive" or "negative" since it's actually alternating current, but you still have to have a "positive/negative" reference for consistent wiring of connections and such, so that's why you get into the "+/-" thing.

The simple answer is that it will make no difference for a single external speaker connection. "Zip cord" or speaker wire is usually marked for polarity with a ridge or a series of ridges, or a paint stripe or dotted line, or even "+" and "-" symbols to indicate one side from the other. If not, you can always trace the wire length or use a test light or volt/ohm meter to determine the correct polarity end-to-end and mark the ends for yourself.

The usual thing is for the marked side to represent "Positive", and the smooth or unmarked side as "Negative", but since the radio audio is Alternating Current and the speaker terminals are isolated from ground, there's really no reason to specifically worry which is which. Yes, polarity does make a difference which way the speaker coil oscillates as the audio current alternates and does make a difference in "speaker phasing" for stereo equipment, but for a single speaker, it will make no difference that you can detect without test gear. Some speaker terminals are marked as "+" or "-" for the convenience of applications that do require correct phasing, but for the usual external speaker connections, it makes no difference.

With all that being said, if the audio output of the radio is not isolated and one side is referenced to ground, there's the chance that a polarity conflict could occur if you're connecting the radio's audio output to another device whose audio input is also not isolated and is referenced to ground or positive. So, a good rule of thumb is to make it policy to always make your connections referenced the same way. The usual reference is that the marked side is always "positive" (center conductor or tip of the connector), and the unmarked side as always "negative".

Did that help or make things worse?

 

[LFN]

Did that help or make things worse?

Thanks for your answer. Of course it helped me very much

 

[iMONITOR]

This might be of some help.

MOTOROLA EXTERNAL (AMPLIFIED) SPEAKER MODS​

Accumulated over time by: Tom Hammond, NØSS

http://www.n0ss.net/motorola_amp_spkr_mods_10jan2008.pdf

 

[Roach112683]

All I did was I bought the Radio Shack Amplified Speaker and mounted it in my vehicle. It is the same as the motorola speaker which is in my police car just designed for scanners and other 3.5mm not a hardwire like the motorola radios.

 

[LFN]

On the Motorola RSN4001 spekear, one cable has a white mark. Can it be + or - ?

I have also a HSN4038A and that speaker has some text on one of the cables, could that be + or - ?

 

[CCHLLM]

As stated in the second post, the standard on any zip cord style speaker wire pair is that the marked line is usually the "+" side. In fact, it's the industry standard. It can be marked with a rib or ribs on that side or a color stripe, or it could be actually labeled as "+" or "positive". This is the standard used by Motorola and all other vendors unless marked otherwise. If the speaker is an amplified unit, it will have more than just a pair of wires attached. There will be wires for power and wires for speaker input, and there should be at least one shield wire. The actual number of wires and the color/marking codes for those will depend on the manufacturer's circuit choices.