Someone Help me with speaker wiring?

[ritheshdsouza]

I have 2 Aiwa speakers of 6 ohms each.. and 3 LG speakers of 3 ohms each.. how to connect to amplifier correctly? I have attached amplifier pic below.. please help me...

 

[Rockingit]

Hmmm..... that's messy.

In mono, you'd probably end up with something like (1 x Aiwa 6Ω in parallel with a 3Ω) in series with an identical pair, going COM and 4Ω and then forgetting about the 5th speaker, but it'll sound awful probably.

 

[ritheshdsouza]

Hmmm..... that's messy.

In mono, you'd probably end up with something like (1 x Aiwa 6Ω in parallel with a 3Ω) in series with an identical pair, going COM and 4Ω and then forgetting about the 5th speaker, but it'll sound awful probably.

1. Can I connect in series 3Ω + 3Ω + 3Ω = 9Ω into COM and 8Ω ?
2. Can I connect one in Parallel 6Ω into COM and 8Ω ?
3. Can I connect in Parallel 3Ω - 3Ω - 3Ω = 4.5Ω into COM and 4Ω?

 

[Avo Mk8]

1. Can I connect in series 3Ω + 3Ω + 3Ω = 9Ω into COM and 8Ω ?
2. Can I connect one in Parallel 6Ω into COM and 8Ω ?
3. Can I connect in Parallel 3Ω - 3Ω - 3Ω = 4.5Ω into COM and 4Ω?

Yes to suggestions 1 and 2. With both connected you will probably get less sound out of each of the three speakers than you will out of the single one, but try it anyway!

If you do 3. that parallel combination amounts to a 1Ω load across the 4Ω output, which is not such a good idea!

 

[ritheshdsouza]

Yes to suggestions 1 and 2. With both connected you will probably get less sound out of each of the three speakers than you will out of the single one, but try it anyway!

If you do 3. that parallel combination amounts to a 1Ω load across the 4Ω output, which is not such a good idea!

Thank you much...

 

[Lucien Nunes]

It's only a 30W amplifier! Overall performance is going to be somewhat limited.

Connecting different kinds of speakers in series can produce strange frequency responses as their impedances are not constant over the audio band. E.g. a 6Ω speaker isn't really 6Ω, that's just an average for the purpose of amplifier matching. Its impedance might vary from 4 to 20Ω at different frequencies, but it won't vary in the same way as a different model. Therefore it's always best to connect different speakers in parallel across the amplifier output which has a low impedance.

My suggestion would be:
3 x 3Ω in series to make 9Ω
2 x 6Ω in series to make 12Ω
Connect those two strings in parallel to make 5.1Ω
Connect to 4Ω output.

The power delivered to each 3Ω speaker will be 3/4 of the power delivered to each 6Ω speaker which is 1.2dB difference and not very important. Their efficiencies and power ratings are likely to be much more different than this.

Not quite all of the amplifier power will be available into the 5.1Ω load but it will not be damaged or overloaded. The stated load impedances on the outputs are optimums, any variation higher or lower will decrease the available power but too much lower can damage the amplifier.

Don't forget that putting an 8Ω load on the 8Ω output and a 4Ω load on the 4Ω output at the same time will overload the amplifier. You could connect 16Ω load to the 8Ω output and 8Ω load to the 4Ω output simultaneously and get full power correctly matched.

PA amplifiers like this use an output transformer, which is how they are able to accommodate a range of different load impedances and drive 100V line from a 12V battery. The 16Ω output winding is tapped at 50% and 71% to give the 4Ω and 8Ω taps. The transformer is also the reason they have poor low-frequency response (this one only goes down to 100Hz, to save size, weight and cost) and high distortion.

 

[ritheshdsouza]

It's only a 30W amplifier! Overall performance is going to be somewhat limited.

Connecting different kinds of speakers in series can produce strange frequency responses as their impedances are not constant over the audio band. E.g. a 6Ω speaker isn't really 6Ω, that's just an average for the purpose of amplifier matching. Its impedance might vary from 4 to 20Ω at different frequencies, but it won't vary in the same way as a different model. Therefore it's always best to connect different speakers in parallel across the amplifier output which has a low impedance.

My suggestion would be:
3 x 3Ω in series to make 9Ω
2 x 6Ω in series to make 12Ω
Connect those two strings in parallel to make 5.1Ω
Connect to 4Ω output.

The power delivered to each 3Ω speaker will be 3/4 of the power delivered to each 6Ω speaker which is 1.2dB difference and not very important. Their efficiencies and power ratings are likely to be much more different than this.

Not quite all of the amplifier power will be available into the 5.1Ω load but it will not be damaged or overloaded. The stated load impedances on the outputs are optimums, any variation higher or lower will decrease the available power but too much lower can damage the amplifier.

Don't forget that putting an 8Ω load on the 8Ω output and a 4Ω load on the 4Ω output at the same time will overload the amplifier. You could connect 16Ω load to the 8Ω output and 8Ω load to the 4Ω output simultaneously and get full power correctly matched.

PA amplifiers like this use an output transformer, which is how they are able to accommodate a range of different load impedances and drive 100V line from a 12V battery. The 16Ω output winding is tapped at 50% and 71% to give the 4Ω and 8Ω taps. The transformer is also the reason they have poor low-frequency response (this one only goes down to 100Hz, to save size, weight and cost) and high distortion.

Thank you for your valuable answer.. please last one..

3 x 3Ω in series to make 9Ω into which slot of COM to 4Ω or 8Ω or 16Ω ? (This positive strings to 4Ω and Negative into COM right?)

2 x 6Ω in series to make 12Ω into which slot of COM to 4Ω or 8Ω or 16Ω ? (This positive strings to 4Ω and Negative into COM right?)

Last Two strings in Parallel right?

 

[telectrix]

In mono, you'd probably end up with something like (1 x Aiwa 6Ω in parallel with a 3Ω) in series with an identical pair, going COM and 4Ω and then forgetting about the 5th speaker, but it'll sound awful probably.

if he's listening to radio1 or any chart "music", it will sound awful anyway.

 

[DPG]

In mono, you'd probably end up with something like (1 x Aiwa 6Ω in parallel with a 3Ω) in series with an identical pair, going COM and 4Ω and then forgetting about the 5th speaker, but it'll sound awful probably.

if he's listening to radio1 or any chart "music", it will sound awful anyway.

Let's face, we're talking a very low budget PA amp here. Sound quality is going to be poor and, as Lucien says, the frequency response will be limited.

Saying that, if the speakers are reasonably efficient (which is more important than wattage) then it may do a reasonable job. I'd go with the 5 ohm configuration personally.

 

[ritheshdsouza]

This is correct na? Please anyone tell me..

 

[DPG]

This is correct na? Please anyone tell me..

Yes, that should be fine.

 

[ritheshdsouza]

Yes, that should be fine.

Thank you so much for reply.. have a great day .

 

[ritheshdsouza]

when i turned on amplifier (volume at zero) humming sound coming from speakers (around 5 seconds) and then disappears. is that normal?

 

[DPG]

when i turned on amplifier (volume at zero) humming sound coming from speakers (around 5 seconds) and then disappears. is that normal?

Is it ok apart from that? I wouldn't worry about it.

 

[ritheshdsouza]

Is it ok apart from that? I wouldn't worry about it.

yes