There are some sound system topics I didn't touch on in All Mixed Up. Others were treated in a compacted way. This page is a compendium of these things, your suggestions and comments, and new information and equipment.
The Great Piano Mic Secret
I figured the same thing with an omni-directional mic would really sound good, and tried it at Pinewoods, where I was running sound. It sounded great; completely natural, very well balanced, and cut out a lot of background noise to boot. I used a Crown PZM mic, and just duct-taped it to the inside of the kickplate. Radio Shack has a similar mic for about $60 that you can try this with (and if you don't like it, they have a good return policy).
If you're going to do this a lot in the same venue, you can use adhesive velcro strips on the pzm and on the inside of the piano kickplate to make installing it easier and more reliable. And the same concept works on grand piano: just slide the mic in under the strings; I find it easiest to reach a good-sounding spot if I slide it in from the bass end, near the edge of the lid closest to the keyboard.
JBL EON Speakers
There are several versions available, with differing wattage and speaker size (10" vs 15"). The 10" size seems fine for most venues, as well as being slightly cheaper and more manageable.
Because one issue is carrying these suckers: while the per-item weight is far less than you'd carry in a single heavy amp used in a conventional system, the handles are less than ideal, making portage a bit clumsy. The overall shape and balance are a bit odd, as well. Bob got a couple of sports-type bags at Kmart, in which they fit perfectly, neatly solving that problem.
Since there's no need to carry a big amp or mixer-amp, any compact lightweight mixer will do. And because the amp and speaker (two of each actually, it's a bi-amped system) have been carefully matched, they also sound a lot better than most unpowered PA speakers.
They connect to your mixer via balanced line-level signal cables; in this case an XLR cable just like you'd use for a mic (if your line outputs are 1/4"-only, you'll need an adapter). These can be extended as far as you'd ever want without the loss of power you get from long speaker wires. It's a far more flexible and professional way to wire a system.
However, it means you need a power cord for each speaker, and ideally (if you want to hear anything) a power outlet to plug the power cord into! So making sure there are outlets near the speaker placement and/or carrying looooong power extensions come along with the territory. And if you use a power outlet far from the mixer, there's an added chance of ground loop hums or shock possibility from mis-wired outlets.
But overall, EONs are wonderful: compared with the usual mixer-amp and unpowered speakers, they are cost-effective, portable, flexible for positioning, and sound great. If I were starting from scratch on a system now, there's no doubt this is the way I'd go.
In a pinch, you can even use one of these without a mixer - plug a single mic in the back and go. Makes an interesting idea for small one-nighters that don't need much sound.
I've seen these as low as $700 for a pair of the EON 10 model (AMS: 1-800-458-4076), which is fine for acoustic music. That's less than a pair of EV 100Sx speakers, and of course the EONs include an amp and a lot more, so you can use an unpowered mixer, or use your powered mixer for monitors.
Here's a link to a reseller's page on the EON speakers. There should be more information soon on the under-construction JBL page.
Update on Powered Speakers
But the best speakers in this general price range (currently, anyway) are now the Mackie SRM450. The first time I heard them my jaw *literally* dropped; these things sound so good that I absolutely had to buy a pair. Their most important attribute, besides sheer quality of sound, is the dispersion pattern, which is 90 degrees horizontally and only 45 degrees vertically. This means that very little of your sound goes up to the ceiling and high on the walls, the sources of most "mud" in the hall.
Unfortunately, they cost even more than the EON G2's. The best deal I've been able to find was $676 apiece at Full Compass (see below). Shipping adds a lot to the cost. Since I bought them a year ago, Musician's Friend has dropped their price to $699, so the Full Compass price might be lower now.
The other downside to the Mackies is they weigh a lot, close to 60 pounds. Add that you need to lift that pretty high in the air to put it on a stand, and find the stand hole in the bottom of the speaker while you're doing it, and they require more muscle than some of us can safely muster.
But once they're paid for and on the stands, they're worth every penny and every ounce.
Update on monitoring
If you have a small band, then I think the advice in All Mixed Up is right on the money: use small 'hot spot' type monitors, mounted on stands, ideally one per musician.
Where this advice falls down is for larger bands. The desirable thing about the hot spots is that their 'beamy' narrow dispersion greatly decreases feedback potential. And if each musician can stand in front of one, they can largely control how much volume they get.
However, this same beaminess makes hot spots useless for larger bands. Even if you have an unlimited supply of them, that just turns the stage into a morass of power cords and monitor signal cables. At this point I think you have to go to a wider-dispersion speaker. The EV-100 series works well in this capacity either as a floor wedge or on stands tilted down. I prefer them to the floor wedges designed as monitors that I've tried, because the EVs have a nice wide, even 110x110 degree pattern. Unfortunately, they're not made anymore -- can anyone suggest a good alternative?
Speaker stand tilt adapters
Where to Buy Stuff
Sound links: Please let me know if you find any other useful ones!
I can't believe you forgot...