Can I run "Mixed" Ohm speakers on my receiver?

[tedman]

I have an Onkyo TX-8050 receiver with Bose 151 outdoor 4 Ohm speakers on the speaker "A" connections for outside patio use. The TX-8050 impedance is set at 4 Ohms for the outside speakers.

I want to add Definitive ProMonitor 800 speakers (8 Ohm speakers) to the "B" connections on the receiver for inside use.

The receiver only allows setting speaker Ohms (4 Ohm to 16Ohm) for both "A" and "B" connections at the same Ohm level.

Could I damage my receiver using mixed Ohm sets of speakers?

If I can run both sets of speakers, should I leave receiver speakers Ohm setting at 4?

Thanks!

Ted

 

[americanaudiophile]

It would not be safe to use a 4 ohm speaker in parallel with an 8 ohm speaker on that receiver. The combined resistance would be under 3 ohms. This might make the receiver go into protection or damage it. Here is how you calculate the combined resistance.
http/physics.bu.edu/py106/notes/Circuits.html
You can add an impedance matching speaker selector that would protect the receiver
http/www.amazon.com/SS4-Speaker-Selector-Impedance-Matching/dp/B002I9XKTE
Set the receiver to 4 ohms.

 

[tedman]

It would not be safe to use a 4 ohm speaker in parallel with an 8 ohm speaker on that receiver. The combined resistance would be under 3 ohms. This might make the receiver go into protection or damage it. Here is how you calculate the combined resistance.
http/physics.bu.edu/py106/notes/Circuits.html
You can add an impedance matching speaker selector that would protect the receiver
http/www.amazon.com/SS4-Speaker-Selector-Impedance-Matching/dp/B002I9XKTE
Set the receiver to 4 ohms.

 

[tedman]

Wow!
Thank You!
Just to be sure...
Purchase the switch you suggested, leave the 4 Ohm outdoor Bose speakers on the "A" speaker connection, connect the switch to "B" speaker connection, connect the Definitive 8 Ohm indoor speakers to output on the switch, leave Onkyo Ohm setting at 4 Ohms and enable protection on the switch....Grateful for your help! Ted