1. "twice the number of cables per speaker to operate" - Yes maybe this is a con for plate amp systems and a pro for rack amp systems - but you can reduce total footage of AC power cable runs by having plate amps with a power-out to daisy chain these IEC power cables (or neutrik powercon) between the powered boxes - the tops or small subs which require half or less the max power from a single 15 Amp AC circuit - that'd be 800W.
Other than on the back of high-end line arrays, I haven't noticed any power outs or pass-thrus on off the shelf powered speakers (there may be some, I just haven't seen 'em). You'd still have to run at least one power cable to each stack and each monitor will have a cable even if daisy chained....the number of cables is the same....they are just shorter. As far as power consumption, I regularly run 6 subs, 4 tops, 6 monitors - driven by 4 driveracks and 6 power amps on a single 15v circuit and have never blown a fuse....and this is outside on ageing GFI outlets.
So, I'd say power consumption would be equal.
2. "If you lose an amp in a powered speaker, the speaker is rendered useless." - Maybe, unless you also install a backup Speakon speaker input - so that in the event of losing the plate amp, you have the option to run a spare rack amp to power that speaker. Or just whip out a spare powered speaker. Or spare plate amp. Anyone here ever replace a blown speaker driver with a spare during a gig? Same concept - replace the plate amp live during the gig with your spare plate amp.
Have you ever seen a Speakon on a powered cab? Certainly, you can do it, but you are adding extra expense and work on every cab.
Oh, and if you are using an amp with DSP - I'd assume you be using an active crossover in the DSP - if so, then you'd need two speakons to cover highs and lows in a top cab...which would also mean an outboard processor and two amp channels.....
As far as whipping out a spare speaker....isn't that kinda defeating the purpose? You'd have to invest in another cab and another plate amp.
Actually, because I always run two tops per side and multiple subs at every gig, I've never had to replace a driver at a gig. I've lost diaphragms, but was able to limp home on one speaker per side.
3. One thing you gotta like is having the sub push air past a Class D plate amp's heatsink in the horn path - this helps cool those transistors even more and make them extra comfortable, now you need a smaller cooling fan.
I'm sure that's true....but amps in a rack have fans.
4. Really like the idea of having one less big piece of critical gear - the amp rack box, this is a "single point of failure" in the sense that, just one unlucky misstep involving the amp rack - whether it gets dropped, falls out of a truck, rained on, falls into a body of water - no more amplification, the show's over, or it never even begins.
Yep, that chance of falling in a body of water is always a possibility - thus, I NEVER accept a gig on a barge....or a rowboat. Any piece of gear can be abused, but my amp rack is solid, lives in a trailer, is on wheels and doesn't get beat about. Rain is not an issue unless it's coming sideways - but, I always have plastic available and on-station if there is any chance of rain.
5. When you have a pro plate amp in each box, this means, when you drop/water-damage/otherwise lose one box, that's OK, there's 7, or 11, or 19 other boxes in the sound system, each with its own independent amp, and the show will go on! Most likely hardly anyone will notice - except maybe the audiophiles and sound techs in the audience!
Unless you are building a touring-sized system, I just don't see this as being applicable to 99% of the folks on this forum. I can power 16 cabs with 6 amps. I'm sure my 6 amps would cost way less than 16 plate amps. Plus, my BFMs are lighter without the amp onboard.
6. Last but not least, many many pro line array systems are class D plate amp based. If they can do it successfully, then why not us DIY people?? Pro line arrays often daisy chain the power, up to the point where the power circuit can handle it, then run a new power circuit, every 2 or 3 boxes. And they also daisy chain the audio signal in. Some line array plate amps are even individually addressable from the Front of House, with a daisy chained Ethernet port to allow individual timing delays and power volumes adjustment of the drivers to permit a finely tuned dispersion of the sound to cover only the audience and not a meter/foot beyond the edge of the general spectator area. And some also provide data back to FOH about driver power soak, or when a driver is getting close to blow, or has blown.
You are absolutely correct (and I have had the opportunity to mix on some large line arrays - it is definitely fun!). Like anything, you should use the right tool for the job. Touring line arrays are a whole different world from the typical weekend warrior....even those with large systems. Those touring systems have techs to help set it all up and they typically arrive the morning of the event that starts that night. And they only use powered arrays - the subs are almost always run from an amp rack.
Should we take some ideas from the big boys? Sure. But, I just don't feel this is one that makes sense in the world in which most of us live. I have a friend with a "powered" system. One sub, two tops, four monitors....I routinely set up my system in half the time it takes them. They have to get power cables all over the stage, then run mic cables to every piece of gear. Then they have to make sure every cab is turned on and all the settings are correct on each one....oh, and make sure the volume knob is turned up....and on and on and on......
Is it easier to design and build a system around powered boxes? Yep. But, it will also take you longer to set it up every time you take it out. I'd rather spend time up front in my leisure to build a proper rack, a well thought-out rack panel and have it wired so that it is plug and play every time it comes off the trailer.
Do powered speakers have a place? Certainly. If you are an acoustic player and just need to carry around a single or pair of small powered speakers and a 2-pound mixer, then go for it. But, once you add subs and monitors, it's time to do it right.
All that said, everyone gets to decide for themselves - especially in the DIY world. But, just because you
can do something, doesn't necessarily mean you should.
