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3x 8 ohms drivers into 2 ohms amp
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Author:  fero [ 22 Jan 2020, 07:59 ]
Post subject:  3x 8 ohms drivers into 2 ohms amp

Good day everyone. I'm total zero at electronics and i'm a little confused i was googling all day but still no clear idea.
Is the impedance written at the left corner of the attached image is correct in that wiring scenario?
Does this setup actually draws a total of 2.6 ohms or 8 ohm??

Author:  Joegtech [ 23 Feb 2020, 22:52 ]
Post subject:  Re: 3x 8 ohms drivers into 2 ohms amp

impedance calculator agrees with you. ... calculator

If you need a higher impedance, try a serial-parallel combination, however, notice the effect on the power going to the speakers ... calculator

Author:  gofar99 [ 24 Feb 2020, 21:56 ]
Post subject:  Re: 3x 8 ohms drivers into 2 ohms amp

Hummm... I'm not so sure. Within the given band pass of each of the three ranges it is possible to get an 8 ohm effective load on the source. For example at very high frequencies the series capacitor on the tweeter will have little reactance so the the source will only see the actual tweeter impedance. At that frequency the other two sections will have rather high impedances due to the frequency variable nature of the capacitor and inductor and will essentially be out of the circuit. At the very low frequencies the inductor in the woofer will have low impedance and the source will see mostly the 8 ohms of the woofer. At those frequencies the other drivers will have much higher impedances because of the reactive nature of their inductors and capacitors. So at any given frequency there should be only "about" 8 ohms seen by the source. In the crossover regions if the components have been properly selected one section will be going up at the same time the adjacent one is going down. This is naturally in a ideal situation. Often speaker designers will alter the overlap frequencies and cause deviation from the desired load. Typical speaker systems are generally not all that linear in impedance across their entire range. You will see peaks and dips. The better ones may only deviate by about 25-33%, some not so good will be off by 50% or more. The value a manufacturer sets for one is nominal and not exact. A good reference on speaker design (and will put you to sleep with the math) is the LDC7 Design Suite (for speakers). It comes with a group of programs that will compute most common crossover alignments like you show in the diagram. It does boxes and driver parameters as well. Not easy to use, but IMO invaluable for answering questions like the one you posed.

Good listening

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