Want to re-use some old sets of speakers we have around with a new receiver
(model to be determined, but a used, fairly inexpensive model). The
speakers are mixed resistance - one set is 8 ohm, another 6 ohm. The third
might even be 4 ohm, it came off a mini-component system and I've only ever
used it for high-range fill in sound.

I'd like to run two of these sets of speakers off the receiver, but realize
almost all receivers in this range would expect 8 ohm speakers. I've
checked a few web sites that explain wiring strategies and resistance
calculations, but they're a little beyond an audio-phobe like me.

Wondering if anyone can venture a guess as to whether I'll be jeopardizing
the receiver amp by mixing speakers?

Help appreciated.

If the receiver is loaded with a lower impedance than what it was
designed to handle, it may be damaged.

--

Jerry G.
======

"Gwood" wrote in message
...
Want to re-use some old sets of speakers we have around with a new
receiver
(model to be determined, but a used, fairly inexpensive model). The
speakers are mixed resistance - one set is 8 ohm, another 6 ohm. The
third
might even be 4 ohm, it came off a mini-component system and I've only
ever
used it for high-range fill in sound.

I'd like to run two of these sets of speakers off the receiver, but
realize
almost all receivers in this range would expect 8 ohm speakers. I've
checked a few web sites that explain wiring strategies and resistance
calculations, but they're a little beyond an audio-phobe like me.

Wondering if anyone can venture a guess as to whether I'll be
jeopardizing
the receiver amp by mixing speakers?

Help appreciated.

In article , "Gwood"
wrote:

Want to re-use some old sets of speakers we have around with a new receiver
(model to be determined, but a used, fairly inexpensive model). The
speakers are mixed resistance - one set is 8 ohm, another 6 ohm. The third
might even be 4 ohm, it came off a mini-component system and I've only ever
used it for high-range fill in sound.

I'd like to run two of these sets of speakers off the receiver, but realize
almost all receivers in this range would expect 8 ohm speakers. I've
checked a few web sites that explain wiring strategies and resistance
calculations, but they're a little beyond an audio-phobe like me.

Wondering if anyone can venture a guess as to whether I'll be jeopardizing
the receiver amp by mixing speakers?

Help appreciated.

You'll have to work out the impedance on each amplifier output. This
isn't only a matter of sound quality. Lower impedances draw more
current. Too low of an impedance can cause the amplifier to overheat,
shut down, or distort loudly.

The formula for parallel resistance is:
1/(1/r1 + 1/r2 + 1/r3 ...)

That's not entirely accurate for impedance but it's close enough for
keeping the amplifier within its proper operating load.

A 6 Ohm and 8 Ohm speaker in parallel is then about 3.4 Ohms. That's
probably OK for a 4 Ohm rated amplifier but not an 8 Ohm rated amplifier.

The speaker off the mini-component system might be as low as 1 Ohm. You
better check it first.

Safest bet would be to put the 4 and six Ohm speakers in series. This gives
10 Ohms which is close to 8. If you play them at higher levels, this will
spread the dissipation out in the speakers as mini system speakers may not
be rated for high power use (you should open the speaker cover and see what
power the driver is rated. I've seen speakers rated for 100 Watts RMS, but
the woofer driver has 15 Watts max stamped on the magnet!

Someone's going to say you'll throw of the crossover and damping off by
putting these speakers into series, but hell, these ARE mini system
speakers! Sound quality is apparently not a priority here.
John

"Gwood" wrote in message
...
Want to re-use some old sets of speakers we have around with a new
receiver
(model to be determined, but a used, fairly inexpensive model). The
speakers are mixed resistance - one set is 8 ohm, another 6 ohm. The
third
might even be 4 ohm, it came off a mini-component system and I've only
ever
used it for high-range fill in sound.

I'd like to run two of these sets of speakers off the receiver, but
realize
almost all receivers in this range would expect 8 ohm speakers. I've
checked a few web sites that explain wiring strategies and resistance
calculations, but they're a little beyond an audio-phobe like me.

Wondering if anyone can venture a guess as to whether I'll be jeopardizing
the receiver amp by mixing speakers?

Help appreciated.

In article
,
"JohnR" wrote:

Safest bet would be to put the 4 and six Ohm speakers in series. This gives
10 Ohms which is close to 8. If you play them at higher levels, this will
spread the dissipation out in the speakers as mini system speakers may not
be rated for high power use (you should open the speaker cover and see what
power the driver is rated. I've seen speakers rated for 100 Watts RMS, but
the woofer driver has 15 Watts max stamped on the magnet!

Someone's going to say you'll throw of the crossover and damping off by
putting these speakers into series, but hell, these ARE mini system
speakers! Sound quality is apparently not a priority here.
John

True, and cheap mini-system speakers have wild impedances. Putting them
in series should be interesting. It could sound horrible or it could
sound like a concert hall. It's worth a try.


"Gwood" wrote in message
...
Want to re-use some old sets of speakers we have around with a new
receiver
(model to be determined, but a used, fairly inexpensive model). The
speakers are mixed resistance - one set is 8 ohm, another 6 ohm. The
third
might even be 4 ohm, it came off a mini-component system and I've only
ever
used it for high-range fill in sound.

I'd like to run two of these sets of speakers off the receiver, but
realize
almost all receivers in this range would expect 8 ohm speakers. I've
checked a few web sites that explain wiring strategies and resistance
calculations, but they're a little beyond an audio-phobe like me.

Wondering if anyone can venture a guess as to whether I'll be jeopardizing
the receiver amp by mixing speakers?

Help appreciated.

Not sure if my wiring will allow for this, but it's worth a try.
Thanks for taking the time.

p.s. If it sounds like a concert hall, I'll let you know ;-)

True, and cheap mini-system speakers have wild impedances. Putting them
in series should be interesting. It could sound horrible or it could
sound like a concert hall. It's worth a try.