Running a crap stereo H/U in mono

[Ae92typeX]

ok, so Im installing a cheap stereo into one of the cars, but will be running it in mono through one speaker (dont ask).
The headunit is stereo, mentions nothing about mono (like thats a surprise).
Is there any easy way (and cheap) I can do this without damaging the stereo?
Cheers

[cespenar]

If you wanted to be rough put the L/R balance all the way to one side, and only hook up that side to the speaker, leaving the other disconnected but with no bare wires so it can't short.

[Ae92typeX]

I could do that, but stereo being stereo- I dont want to loose out on half the music i.e. sometimes you have say drums in one and singer in other.
I'd like to hook up mono, but getting it all.
Before anyone suggests bridging the two together is not the thing to do.
I could get a twin voice coil speaker, but thats an expense thats not worth doing for this exercise.

lol, is it difficult cos it is so lame

[10speed]

surely you can find one more speaker somewhere?

[pidge]

One possibility:

Get four 1 ohm 5 Watt (or so) resistors.

Connect one lead of Resistor 1 to the headunit LH +ve output
Connect one lead of Resistor 2 to the headunit RH +ve output
Connect one lead of Resistor 3 to the headunit LH -ve output
Connect one lead of Resistor 4 to the headunit RH -ve output

Connect the free leads of resistors 1 and 2 together. Connect this join to the positive terminal of the speaker

Connect the free leads of resistors 3 and 4 together. Connect this join to the negative terminal of the speaker

YMMV, IANAL, Others may disagree etc.

[Blackrazor]

It would work fine if it wasnt for the fact that a speakers impedance (in this case 4 ohms) is only a nominal value - in reality it will vary anything from 3 ohm all the way up to 100ohm or more, depending on input frequency and crossover points, etc.

So while that would nominally make it an 8ohm speaker, it would also completely mangle the impedance curve - for example, the portions of the curve that were 3 ohm will now be 7 ohm (133% increase) whereas the portions that are 20 ohm-ish will now be 24 ohm-ish (an increase of only 20%).

Translation - it'll work, but i wouldnt want to listen to music on it

The other problem with it, however, is that when you bridge, the amp effectively has to change to a push/pull mode (i.e one set of terminals flips phase). Now unless the headunit is designed to do that (90% arent) you'll run into serious issues

[Ae92typeX]

surely you can find one more speaker somewhere?

lol, theres no issue with getting/buying another speaker.I usually have fair quality sound systems in my vehicles...its just something Im doing.

One possibility:

Get four 1 ohm 5 Watt (or so) resistors.

Connect one lead of Resistor 1 to the headunit LH +ve output
Connect one lead of Resistor 2 to the headunit RH +ve output
Connect one lead of Resistor 3 to the headunit LH -ve output
Connect one lead of Resistor 4 to the headunit RH -ve output

Connect the free leads of resistors 1 and 2 together. Connect this join to the positive terminal of the speaker

Connect the free leads of resistors 3 and 4 together. Connect this join to the negative terminal of the speaker

YMMV, IANAL, Others may disagree etc.

Cheers, sounds like just what I was looking for. Any other opinions/confirmations?...I should really get out my old auto electric books and re-learn the ohm stuffs

[Blackrazor]

To help you understand what i'm talking about, this is the 'actual' impedance (vs frequency) of a real 6 ohm driver. Frequency (Hz) on the X axis, impedance (ohms) on the Y axis. Note that this is a '6 ohm' driver, but the real load varies between as little as 4.6 ohm and as much as over 20 ohm, depending on load

[Ae92typeX]

Cheers for that.Makes sense when explained.
Well...maybe the crappy stereo will run one sided. not what I wanted...but its not really important or the end of the world.

[Blackrazor]

Just a note - many headunits actually have a mono mode you can activate in a submenu on the headunit that will combine the stereo channels and feed the resulting mono channel into each channel anyway It may pay to look-see through the manual

[Ae92typeX]

cheers