Resi client has around 5 zones of outdoor audio for playing music while entertaining. The current setup is very simple. Control4 matrix feeds Control4 amps, which powers 5 pairs of 8-ohm speakers. All zones are stereo, and are wired with 14/4.

One of the zones is the bar area, which is now undergoing a significant renovation. As where currently there are left and right speakers flanking the area, the renovated space will be a somewhat sprawling 500 square foot collection of seating areas.

Since there won't really be a listening stage and running new cabling from the rack won't be easy, I'm considering a 70V system powering a bunch of mono speakers. That will leave two conductors of 14ga wire free for a subwoofer.

While this seems pretty straightforward, I've never done this sort of configuration (i.e. a half dozen 70V landscape speakers playing mono with a single subwoofer placed strategically in the space.) In fact, I pretty much always do stereo 8-ohm setups.

Is there anything glaringly inappropriate about how I'm thinking of approaching this?

Nope. For larger spaces, it's appropriate. Consider multiple subs to make for more uniform sound distribution.

Don't be afraid of 70V. The physics is the same, but 70V load calculations are so much easier. Consider the complication for electricians if we specified the resistance of lamp filaments, and had a big bunch of possible power line voltages, rather than one voltage and the lamp power draw. The very simple question "can I add a lamp to this circuit without overload?" becomes much more difficult to answer.

Fred and buzz have it covered.

Once you're done you may never spec a stereo system again, even if you lay out the speakers exactly as you've done for this system. If you want music in an area, it simply makes no sense to make it possible to be close to one channel of information and far from the other... making it mono puts all the information everywhere.

With the multizone amp they possible have level control of the various subzones. I would find out if they care about tayloring the level of zones or if they are ok with all the speakers increasing or decreasing in unison. That is always my fear with 70V

Mrtristan, companies like DBX and QSC offer commercial audio matrix devices that allow end users to adjust individual zones....

If you dig around, you can find 70V Volume controls. Actually, auto transformer 70V controls existed before the versions that we use for home audio. Unfortunately, the 70V versions are mono.

In typical 70V installations we don't need the control granularity (Volume control for each speaker) that one would use in a home. Speakers designed for 70V applications typically incorporate a multi-tap transformer. Depending on the size of area covered, the installer selects an appropriate "power" tap. (Think, dining room and restrooms driven by the same amplifier.)

Actually, I used this concept to design my own room Volume controls for home audio before stereo auto transformer controls were available on the market. This was a time consuming mess, but the result sounded better and was much more efficient than L-pads.

Check out the landscape series Episode speakers from SnapAV. They have multi tap 70V options as well as 8 Ohm options. They also sell a kit that comes with a Crown amp that has a preset EQ setting for the speakers.

Yeah, I’ve been looking at SnapAV’s new hybrid amp, which can drive 70V speakers out of one channel and an 8ohm sub out of a second channel. (I think they’ve moved away from the Crown amps in favor of their own kit.)

Thanks to all for the input.

Here is the hybrid SnapAV amp I'm looking at:

[Link: snapav.com]

It has 2 channels in, which can be mixed down to mono. And, it has two channels out; one output can be set to 70V to drive the satellites and the other output set for 8 Ohm with a low pass filter to drive the subwoofer.

Functionally, it seems perfect, and it's all in a 1U package. Unfortunately, the reviews are not so inspiring.

Pick up the Crown from Fred but use the Landscape speakers.

A Crown could run 24/7 for 10-15 years.

Crown DCi to be exact. These are solid.

The CDi series, which was sold with those packages, do fail after some time (as low as 2 years in bad environments). Experienced this way too many times.