Is this speaker wireing method parallel, series or something in between?

Question

Suppose I have 2 cabinets that each have (2) 8 Ohm speakers in them. One speaker is rated for 200W RMS/ 400 Peak, & the other is rated for 500RMS/ 2000 Peak. If I wired them like this: + & - inputs to 1st speaker (500 RMS one) and then + of 1st speaker to + of 2nd, and then - of 1st speaker to - of the 2nd, then would that be series? Would that make it a 16 Ohm cabinet? What would the RMS/ peak be on the cabinet? Would the 1st speaker recieve full power and the 2nd less? Can someone please break this down for me? Thanks.

Answer 1

For speakers, The 8 Ohm rating is NOT resistance, but Impedence.
Speakers have different resistance depending on the input frequency.

So unless your receiver/output has explicit multi-speaker outputs it is not recommended to do connections like yours. You may damage both the speakers and the receiver.

Your connection is in "parallel"

Answer 2

To calculate the final impedance is easy:

Let's suppose this:

(0+) (0-) are amplifier terminals
(1+) (1-) are speaker #1 terminals (8 Omhs, 200 W)
(2+) (2-) are speaker #2 terminals (8 Ohms, 500 W)
and ---- is a wire

Then.

PARALLEL WILL BE:
(This is what you are doing)

(0+)----(1+)----(2+)

(0-)-----(1-)-----(2-)

see this picture:
http://www.maplin.co.uk/InfoCenter/images/Speak34.gif

Final impedance is calculated as:

1 / X = 1 / A + 1 / B

Then
X = 1 / ( 1 / A + 1 / B )
X = 1 / ( 1 / 8 + 1 / 8 )
X = 4

Then final impedance in parallel will be 4 Ohms.

SERIES WILL BE:

(0+)----(1+) (1-)----(2+)

(0-)---------------------(2-)

See this picture:
http://www.maplin.co.uk/InfoCenter/images/Speak36.gif

Then final impedance is calculated as:
X = A + B

Then
X = 8 + 8
X = 16

Then final impedance in series will be 16 Ohms.

Acoording to the website I post below the final power rating will be calculated multiplying # speakers by the lower power rating. (Amplifier power will be distributed equally given that speakers combined are the same impedance)

Then

2 x 200 W = 400 W

Final power is 400 W RMS.
For peak usually to asume twice the RMS rating will be enough (and given that your lower rated speaker's Peak rating is twice as its RMS rating). So we'll have 800 W peak.

This power rating calculation will be valid only when combining speakers with the same impedance (Ohms) and when drived at the final impedance of the complete system.

So for your specific speakers you will have:

400 W RMS/800 W peak at 4 Ohms (parallel wired).
400 W RMS/800 W peak at 16 Ohms (series wired).

Answer 3

TV Guy is right, they are in parallel. What you need to find out is, what is the MINIMUM impedance rating of your AMP? Ignore all the _ _ _ watts RMS, because that has nothing to do with your question or your concerns.

If your amp is rated only at 8 Ohms, then do not hook them both up. If it is rated at 4, you can try it. There will be some frequencies that will be less than 4 ohms, but these may not bother the amp. If the amp runs hot or shuts down, you can't do this. If the amp is rated at 2 ohms, there should be no concern. It actually helps that you are using two different speakers, because they will not be showing identical impedance curves.

Answer 4

Hi there. Loudspeaker impedance is resistance that varies with frequency.If your speakers have a nominal rating of 8 Ohms their impedance will vary over their frequency range from as low as 3 Ohms to as high as possibly 40 Ohms.
Your amplifier must be able to deal with these impedance variations producing the amount of power necessary to drive the speaker at any frequency without distortion.
Your amplifier should produce a constant voltage across the speaker terminals whatever the load
In your case for your amplifier to produce 200 watts RMS into your 8 Ohm speaker your amp must be able to produce 40 Volts at the output terminals (watts equal voltage squared divided by impedance If you connect a 4 Ohm speaker (half the original load)the same 40 Volts would produce 400 watts and if the load goes down to 2 Ohms the amplifier will produce 800 watts The amp should have high current capability to do this.Therefore the amplifiers power supply must also double its current delivery to the output transistors for this to happen.

Answer 5

both speakers are 8 ohms. if you hook one set as parallel, you effectively divide the resistance. you risk blowing one set of speakers on the one channel of your amp and overloading the other one channel on your amp