Erm...my receiver has two impedance settings and my speakers have two impedances.

thurber

Active Member
I imagine it's not a big deal but I don't want to bust the receiver, or the speakers.

This Pioneer VSX-D1S has a switch which I can't be the first person on earth to find confusing (below from manual):

Screen Shot 2018-06-24 at 9.36.27 AM.png
Screen Shot 2018-06-24 at 9.36.34 AM.png

Then the speaker (EPI 100V) has a DC impedance and a nominal impedance:

Screen Shot 2018-06-24 at 9.40.59 AM.png

So...anyone know how to switch this?
 
8ohm speakers. Do you have the impedance graph for the speakers? If it says 8ohm nominal, then go with that.

Mode 1
 
It's hard to read on my phone, but no it does not look like an impedance graph. You want frequency on the bottom and ohms on the side.
 
(Hal Douglas voice) "One speaker. Two impedances. Two switch settings. And the urge to get things just right. Here's the story of a man, a set of wires, and the decision that would confound him temporarily for a half hour or so. From director Z. Adamson, it's...Audio Karma. Summer 2018"
 
(Hal Douglas voice) "One speaker. Two impedances. Two switch settings. And the urge to get things just right. Here's the story of a man, a set of wires, and the decision that would confound him temporarily for a half hour or so. From director Z. Adamson, it's...Audio Karma. Summer 2018"

Not sure I follow, but think of it this way.

Nominal impedance is an approximation. It is the "designed impedance" of a device....In this case the speakers voice coil. It is an approximation because it will vary with frequency.

But, you don't need to worry about that. All you need to know is that you have 8ohm speakers and you need the amp set up as such and from the looks of it, that is mode 1.
 
I imagine it's not a big deal but I don't want to bust the receiver, or the speakers.
The switch balances power from the mains and rears to the center. It all depends upon the sensitivity of the center.

When you choose to connect two sets simultaneously (via A+B switching), you must use higher impedance models. Running two 8 ohm speakers results in 4 ohms. Ok. Two four ohm speakers result in 2 ohms. That will overheat and smoke the receiver.

Most speakers have a "nominal value" since it varies by frequency. In your example, you chose graphs of other parameters.
 
thurber: Well, what's the complete set-up? Do you only run one pair of these EPIs (and neither a center nor rear speakers)?

In any case, in mode 1 your receiver obviously wants to see at least 8 Ohm on each power-amp channel. Whereas in mode 2 it can drive one or two channels (i.e. either the center or the fronts) with a 4 Ohm load, while the other channels would still want to see a minimum load of 8 Ohm. And on those channels with two terminals in parallel the minimum for each terminal would of course double for simultaneous use. So it's actually not too difficult to understand.

Greetings from Munich!

Manfred / lini
 
Then the speaker (EPI 100V) has a DC impedance and a nominal impedance:

index.php
Something is wrong here. Each speaker has a DC resistance (aka DCR). This is usually 80% of the nominal impedance. So 8 Ohms impedance should calculate to 6.4 Ohms DC. OR..... if the DCR is truly 4 Ohms, then you would multiply it by 125% to get the approx. nominal impedance, which would be 5 Ohms. Did you actually measure the DCR?
 
Something is wrong here. Each speaker has a DC resistance (aka DCR). This is usually 80% of the nominal impedance. So 8 Ohms impedance should calculate to 6.4 Ohms DC. OR..... if the DCR is truly 4 Ohms, then you would multiply it by 125% to get the approx. nominal impedance, which would be 5 Ohms. Did you actually measure the DCR?

Nope. Nominal impedance is a made up number, typically provided by the manufacturer based on the impedance over the frequency range of the speaker. Using a factor of 1.25 is strictly a convenience that should not be relied upon for any specific speaker. The DCR is only the resistance in ohms at dc. The impedance can, and does, change a lot based on frequency.

The graph below shows the impedance curve for an EPI 50, which varies between 4 and 20+ ohms over its frequency range. The EPI 50 is rated as a nominal 8 ohm speaker.
epi%2050%20impedance%20curve.png
 
Well. if the Human Speakers data is to be accurate, I would believe the DCR, which places the system impedance as 5 Ohms in my book. I would drive them from a 4 Ohm transformer tap.
 
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