Has anyone tried this?

Hooking up the left speaker to the left and surround left channels, hooking the right speaker to the right and surround right channels, and running the thing in 5channel stereo mode. Should work, and there should be benefit (or not) depending on how the reciever is designed. But, sounds like a fun thing to try so I'm gonna play with it a bit.

Perhaps you mean to run an extra set of speaker cables and split the input wiring to your loudspeakers, as in the "bi-amp" of your topic title. I'm not sure you'll experience true bi-amped stereo with the 5-Stereo signal matrix modified for an active center speaker. Certianly something you might experiment with if you got the time. The speaker delay/distance settings for all channels involved in the bi-amping might need to be adjusted to the same value.

If you're talking about having two outputs wired in parallel to a single speaker while in a surround mode, you might want pull the reins in and shout "Whoa!" Why?

1) Most receiver output stages simply are not meant to be tied together!

2) Even output stages in some pro gear that will tolerate such wiring must be practically guaranteed to be outputting the same signal at the same amplitude and, ideally, perfectly in phase.

Imagine this scenario: a "whoosh" sound is designed by the audio production team to travel from the front speakers, then envelope the whole area without localization, then sweep out the back.

In the first third of this scenario, the front outputs begin to produce a signal while the surround outputs are by design absorbing any back EMF present thus providing damping to the surround speakers. But wait! The front outputs are supplying a voltage directly to the surround outputs which will "absorb" this voltage into a very low impedance - the fronts are driving a near short comprised of the surround output transistor stage! All output stages are stressed.

In the middle third of this timeline, the front and surround channels are actually attempting to output through shifting phases, including 180° out-of-phase. At some moment in time the fronts are attempting to output 12 volts "positive" while tied to the surround outputs attempting to output 12 volts "negative." If you've got independent power supply stages feeding the output stages, this is akin to using jumper cables on two cars but with plus-to-minus and minus-to-plus - read massive currents! If you are feeding all output stages from the same power supply, this is akin to placing four or more output transistors in a row between the positive and negative terminals of a car battery.

Your output stages had better be "dead short" protected or better.

Third section of this scenario is like the first, except the fronts are at their 'zero point' while tied to the surround channels trying to achieve an output.

I highly doubt you'll hear pleasing sound during such an event.

If you've already tried this, I hope you've kept the volume at very low levels. If not, you will likely need to saddle up and head for either Repairsville or Replacementown.

I doubt you mean to try the output channels tied together, but just in case someone does get that idea, I thought I'd mention these problems.

One problem with this scenario (aside from the engineering concerns that bestbang has touched on) is the fact that most (or all) surround receiver users are likely to want to play some Dolby Digital or DTS material at some sort, at which point (1) 5 Stereo is no longer an option for most receivers and (2) your surround speakers' signals are going to your mains right along with the main signals, creating a very weird mix of noise.

My speakers are biampable so it does not matter if the two signals are exactly in phase. One signal goes to the high crossover, one goes to the lower crossover, so there is no risk. I woud never attach the same piece of metal to different outputs.
Down the road I may be using this 7 channel receiver as a stereo receiver, so I am wondering whether the best performance comes from just using speaker mode, or doing what I have described above.

I'd be wary of doing it, partly because the only way to guarantee that you have the option of running 5 stereo with all sources is to only accept PCM or analog inputs - I believe that even a Dolby 2.0 source (such as any DVD or many cable and satellite broadcasts) will rule out the option of 5 Stereo and leave you with either your low or high frequency range out in the cold.

Well, the first thing I did was set my DVD player to PCM output only. You guys arn't very supportive of tinkering
Ideally it should double my power!

MAYBE you could POSSIBLY do this using 'direct' with the stereo signal y'd to inputs,then speaker outs to appropiate speakers,but,i would NOT do anything discussed in this post(even what i just explained).and i am a fan of passive biamping.

Well, I don't understand everyone's hesitance, espicially since it works fine. The circuitry of it is perfectly safe. It sounds good, though it is not dramatic enough of a difference to notice right away, so I can't say if it is actually better. Changing wiring takes a few minutes so theres no way to A/B the setup quickly.

My hesitance is because it is an idea that, while feasible, comes with a number of limitations that the average user might not recognize when perusing this thread (even aside from the debate that bi-amping can often generate). Speakers must be bi-wire/bi-amp capable, receiver must support a "5 stereo" mode (which the 1070 does, of course), sources must be restricted to PCM or analog, and once it is set up no other mode can be used. Leave any of these out, and the approach either can't be used (speakers that aren't bi-wire/bi-amp ready) or will result in modes where the resulting sound is "broken." If the individual understands those limitations and is willing to accept them (as you appear to do, although I was not familiar enough with you to know that at the start of the post), then it is a "safe" experiment. Would I recommend it as common practice for a surround receiver and a typical user? Absolutely not.

By the way, I assume you've set the speaker distances the same for both mains and surrounds (I'd actually set both to zero if it were me). That just occurred to me as I was typing this post - thought I'd toss it out there just in case.

well, i just got my PE order,and since my amp is still out front(not in the rack),it took me about 10 mins. to be back up in running in passive biamp(been about 6 months) and yes,it does sound better,no i'm not doing a/b,blind,dbl.blind,just me and my ears.

if nothing else,the four bananas sure look cool comin' out the back of the speakers(one's in plain view when entering the room)

lanion,if you like it,do it,it's your system!but you made a comment that 'it doesn't matter if the signals are exactly in phase,where my understanding is that out of phase signals tend to have cancellation(sometimes desired) and i can not see that being a benefit in one pair of speakers.maybe i'm missing something.