Parallel/Series Wiring Question

[Javachip]

I have searched this topic, read about it, and still don't quite get it.

I am considering the Aurasound NS4 4 inch, 8 ohm, 84 dB drivers for an open baffle project.

1) What would the overall sensitivity be with 2 drivers in parallel? Would it be 84 +6 (second driver) +3 (open baffle) = 93 dB?

2) How about 4 drivers? In this case, how should they be wired, in order to keep the overall impedance at least 4 ohms?

3) If the driver was available in a 16 ohm version (it currently is not), would that offer any advantages over the 8 ohm version in a 4 driver application?

3) In series wiring (positive terminal from amplifier to positive terminal of first driver, negative terminal of first driver to positive terminal of next driver, negative terminal of final driver to negative terminal on amplifier), are all of the drivers in phase?

Thank you.

[Cal Weldon]

Hi javachip,

I don't know if you searched but there are many discussions in the forums about this. You will also continue to get varying opinions on this isuue. I am happy with my conclusions. Yours might differ.

1. If you put two drivers in parallel you will get a 3dB increase from the extra driver as you now have two radiating surfaces. You will also get an extra 3 dB from the amp as the impedance is halved. So if the volume pot is set the same it will offer you 6dB more. So 2 at 84 gives you 87 and whether you take into account the extra 3 from the amp is up to you.

2. Wire two in series and the other two in series then parallel those two groupings. Or parallel two and parallel two more then series the two groupings. I prefer to series first and then parallel because if you lose one of the two groupings, your impedance goes up instead of down which can damage your amp.

3. In a four driver application, if all are 8 ohms or your final impedance will 8 ohms (or 2 or 32). The 16 ohm versions will be 16 (or 4 or 64). The 16 I would say is used most often in a two driver application to result in 8 ohms.

Other question #3. Yes that is in series and yes the cicuit is in phase. Remember, the speed at which the electrons are traveling makes it impossible for the human ear to detect that one drivers recieves it's signal infinitesimally sooner than the other. No sooner has that happened than the circuit reverses (AC) and it happens in the opposite direction.

[Doc.Doom]

Hello javachip
I agree with Cal, but to make things more exciting go to www.customanalogue.com and look at the Elsinore speaker project. This is quite a novel idea. But remember if you shoot for 4-Ohms you will pull more current from your amp as apposed to 8-Ohms. But 8-Ohms being safer if these speaker swing down be low 4-Ohms in the lower Frq. (Le) is the reading I would pay attention to.

[lndm]

Originally posted by Cal Weldon
2. Wire two in series and the other two in series then parallel those two groupings. Or parallel two and parallel two more then series the two groupings. I prefer to series first and then parallel because if you lose one of the two groupings, your impedance goes up instead of down which can damage your amp.

Not to be a negative Nellie, as this is generally a good point. The only difference I can see between the two is in the second case, the centres are connected (like an 'H').

If a driver goes open: In the first case, the impedance jumps to 16 ohms, in the second case, it jumps to 12 ohms.

If a driver shorts (surely less common?): In the first case, the impedance falls to 5.3 ohms, in the second, it falls to 4 ohms.