Series/Parallel speaker circuit

[Jack N]

 

[Russdawg1]

Yep

 

[Jack N]

Thanks.

 

[HTfreak2004]

Why would you want to wire the negative binding post from one speaker to another speakers positive binding post? According to your third example. Your first picture is a series circuit meaning one path from your amp positive output to the first speaker positive input and then a second wire joining the two speaker positive inputs and then one path from the second speaker negative output to the first speaker negative output back to the amp negative input. A parallel circuit requires you to hook the speakers not to each other but directly to the main positive output of the amp directly and have a separate ground wire from each speaker back to the amp. Your basically trying to provide the same wattage to both speakers off one amp channel which drops the ohms from say 8 to 4 assuming 2x8 ohm speakers. You don’t want to do this however because your speakers may say compatible with 8 ohms but may actually average 8 ohms across there frequency response yet place a huge current draw on your amp when playing deep bass where the actual load seem by your amp is between 2-6 ohms. If your amp is not stable into 2 ohms I will not be able to drive the speaker or speakers impedance and shut down or destroy your amp and speakers. You would need a bridgible amp to do what your talking about. Most of not all home equipment is not bridgible. Using a second amp with equal gain to drive each speaker is the smart thing to do!

 

[ryanosaur]

I've seen this mentioned a couple times as I've been researching speaker design...
What is the ultimate goal here?
Is series-parallel just about keeping the impedance at, per OPs example, 8 ohms while using 4 matching drivers to increase output? Is there something else that happens in the circuit that affects performance?
Thanks!

 

[TheWarrior]

I've seen this mentioned a couple times as I've been researching speaker design...
What is the ultimate goal here?
Is series-parallel just about keeping the impedance at, per OPs example, 8 ohms while using 4 matching drivers to increase output? Is there something else that happens in the circuit that affects performance?
Thanks!

A lot of off the shelf woofers are significantly less sensitive than tweeters, for example. So for those woofers to produce the same SPL for a given voltage, you would need multiple woofers.

The only reason you don't see a lot of quad woofer designs is simply build cost. But otherwise Series-Parallel is an excellent solution to a common problem with matching driver impedances.

 

[TLS Guy]

View attachment 28855

Lets be quite clear. That is a series parallel circuit. It can be used to connect a number of the SAME individual drivers together. It can NOT be used to connect dissimilar drivers and ESPECIALLY not completed speakers together.

 

[HTfreak2004]

It’s also important to know what load the speaker imposes on the amp at low frequencies as resistance is not a constant but an average figure. My speakers say compatible with 8 ohms but the impedance graph shows 2.5 ohms at 104 hz per main channel. The compatible with number is a reference for average across all frequencies only. Usually an amp should be stable to support twice its ohm load eg 4 ohm for 8 ohm. My amp is 2 ohm at its max wattage output (180 watts into 8 ohms, 340 watts into 2 ohms) Series circuits combine all resistors in the chain like Christmas tree lights. Parallel circuits allow each resistor to see basically the same power with essentially no voltage drop. The amp on the other hand must be stable enough to support the added load since each speaker is capable of drawing closer to its max power in parallel than in series. If two speakers draw 2.5 ohms at 100 hz for example that creates 1.25 ohms seen by the amp. That won’t go over well if they share a parallel circuit!

 

[JerryLove]

Why would you want to wire the negative binding post from one speaker to another speakers positive binding post?

To add a second speaker while increasing the resistance presented to the amp.

Inside a speaker, this could be multiple drivers where you wanted to raise the resistance to better pair. With two separate "speakers", this could be because you want to drive two but lowering the resistance represents a risk for the amp.