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March 2nd, 2017, 4:12 pm
So I have four of the same wookers
is there any performance difference in wiring them as two in series in parallel with two in series or
two in parallel in series with two in parallel
March 2nd, 2017, 4:18 pm
same - same
combined impedance will be equal to that of one woofer.
March 2nd, 2017, 4:31 pm
My guess is that you are talking about the Carvers. Shouldn't they be wired the way they were when originally manufactured?
The Carvers do march to the tune of a different drummer. Normal conventions do not apply.
March 2nd, 2017, 5:18 pm
Factory was 2 in parallel in series with two in parallel
I just wanted to ask "if there was a better way"
Hey Walt when have you ever followed the factory ( other than the Quads)
March 2nd, 2017, 5:32 pm
Speakers measure (DCR) 3 ohm each the array measure 3ohm maybe I will hook up the other set the other way just the fuck with Walt
March 2nd, 2017, 5:35 pm
It's always better to drive speakers, especially those with voice coils, in parallel. Speakers are motors and direct connection to the amp will give the amp a better chance of keeping the driver under control and give the drivers less chance to interfere with the other(s) it is in series with. If you are using a passive crossover this will make the components much larger. This will also lower the impedance to the amplifier so you will need an amp able to drive the lower impedance. If the Carver woofers are 16 Ohm, then it's no problem to series all four.
March 2nd, 2017, 5:43 pm
same-same in this instance
March 2nd, 2017, 5:44 pm
The problem is how closely the speakers are acoustically coupled to one another. Since the Carvers are open baffles the acoustic coupling is not that strong. If the speakers were in a closed box the acoustic coupling (low frequency) would be very strong and modify the equivalent circuit of the speakers (they wouldn't only be a resistor and inductor in series) with an analog mutual inductance or capacitance (I don't know which). Mechanically there would be an air spring coupling the speakers in a sealed enclosure that is not present in an open baffle.
March 2nd, 2017, 6:03 pm
Impedance and amplifier capabilities aside, wiring drivers in series can sometimes cause problems. If you look at a dynamic driver impedance curve, with increasing frequency, below resonance the phase is leading. At resonance the phase is 0, that is neither leading or lagging. Above resonance the phase shifts to lagging. If you put drivers in series and the resonance is different (no two drivers are exactly the same) you will have one driver with a leading phase and the other with a lagging phase. At that point the impedances of both drivers are high so the amplifier has the minimum control of cone motion. You can actually get the two drivers out of phase. I have seen this with a stroboscope and what happens is that you get a dip in the response at resonance due to out of phase cancellations. At last year's Midwest Audiofest, one of the speakers had dipole woofers in series and the builder did not understand why he got the dip when both drivers measured flat when used individually. It was a perfect example of what can happen with drivers in series at the point of resonance.
When wiring them in parallel assuming you have a good amplifier than can handle the load, that situation will not happen. If the output impedance of the amp and also the impedance of the low pass section of the crossover is reasonably low, any phase differences will be immaterial.
This is primarily of concern with woofers because with mids and tweeters you do not normally use them in the range around resonance. However with woofers you always go through the resonance region. I'm attaching a typical woofer impedance curve to show what is happening. Note that although the stated impedance is 4 ohms, at resonance it rises to around 42 ohms, severely limiting the ability of the amp to correct any problems. If two were in series that impedance would rise to 84 ohms further complicating the issue.
- Typical driver impedance curve.pdf
- (89.87 KiB) Downloaded 196 times
March 2nd, 2017, 7:19 pm
Thanks for all the info
Since I am not designing something new and I am not going to replace drivers I have to stick with what I have. If I wired all in parallel I would be down to 1.5 ohms so I am forced to go the series- parallel or parallel route.
I was just curious if there would be a best way. The factory went with parallel-series route. Supposedly this was Bob Carvers baby but I doubt I will be impressed with them, its just the latest "hit" I am injecting
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