If your rack back is closed you should think about thermodynamics. Have at least a 1u vent hole in the bottom and top of the rack.
As the heat builds up in the case the hot air will escape through the top vent. At the same time it will suck cold air from the bottom vent creating a constant cooling air flow inside your case.
This should eliminate the need for fans, at least for low powered devices like this...
x32, x32-rack, s16, p16, iNuke 6000dsp, deq2496, dxc2496, src2496, misc other behringer gear, StudioLive 24, StudioOne Pro, Cubase 4, Ableton Live 8 Suite, Reaper 4
I have mounted a 1U vent grille above and below the S16. I've considered leaving it open, but I expected someone to use this to store something in that hole sooner or later - for example, sheet music -- which would effectively insulate the top of the S16.
There's also a vent grille in the bottom slot of the case, below the 4-channel amp, and a big hole above the amp where the speaker cables go because I was a) too lazy to make a speakon patch panel, b) already over budget, and c) thought the less connectors in the speaker cable the better.
We've already been running with the back closed for some sessions in the practice room, but of course then the case is not in direct sunlight, and I hadn't checked it for temperature, either.
Leaving the back lid ajar would allow for some cross-ventilation as well. The challenge here is to fix the lid in place. On this gig, we're playing open air from a stage that is built from a trailer. Only this time the event organizer didn't provide the usual stage, but a smaller one, so the band had to rearrange things, and one of things we did was put one of those long folding tables to hold two monitors for the singers and the S16 rack case. If I had opened the lid and not fixed it somehow, it probably would've fallen off, because the table wasn't very wide. Next time I'll be prepared.
How hot does your S16 get when you've been using it for a few hours? above the power supply?
I usta use the 3" fans that one would find in the large racks of corporate computers to cool of power amps.
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First, let me apologize for the lengthy post but I feel that the discussion is warranted.
Michael, we have all had electronics that tend to run rather warm but from what you are saying, you feel that your S16 was running considerably warmer than you expected. Instead of pointing to the S16 as the problem, perhaps something else is going on. From past experience with switching power supplies, I know that those power supplies are completely dependent on adequate mains power (proper voltage & current to those devices with switching power supplies).
You stated three things that I would be concerned about before I pointed my finger at the S16 as the source of the problem:
1) Was this a one-time problem or do you also have the same problem at other venues where you are running your system at your normal operating SPL?
2) You stated that your band was performing " . . . on open air from a stage that is built from a trailer. Only this time the event organizer didn't provide the usual stage, but a smaller one, so the band had to rearrange things . . .." It sounds like this was a "make-shift" setup by the event organizer, meaning that a number of things were thrown together at the site without any real concern for your system needs (I'm thinking about power distribution here!)! On too many occasions, I've seen adequate electrical power for the sound system was never properly considered by those putting on the events. I'll talk about this later in the post.
3) You stated that there is a 4-channel power amplifier in the same rack as the S16. Not only can 4-channel power amplifiers generate considerable heat but, more importantly, they require considerable electrical power. I assume that all the devices in your rack are connected to the same electrical source which in on too many occasions an extension cord plugged into an electrical circuit that is shared with additional devices.
It sounds like you might want to consider the lack of available electrical power as the reason for your problem, that is, consider that the lack of proper power distribution as the reason for the heat buildup and that would be a problem that would, in time, lead to equipment failure. More times than not, current (and voltage) limiting in more often than not the reason for equipment running at temperatures higher than normal operating temperatures. Production companies almost always include an adequate power distribution as a necessary component of their sound systems--it has become a necessity, not a luxury!
I am not saying that power is your problem but that I would check out your electrical power requirements first. One of my clients is an 8-piece funk band with a large sound system (large for a band but small compared to those of a sound company). Their main PA rack included 8 power amps in a real tall road case powered by 2 power strips rated at 15 amps each. Also in the rack were numerous effects processors, eqs, power cord for their mixing console, and similar electronics. On one occasion, when troubleshooting their system, I notices that both power strips were plugged into the same wall outlet. Essentially, their entire sound system was running on 15-20 amps of available. In that scenario, I would EXPECT the electronics would run "hot" and that their equipment failure was NOT out of the ordinary. Their solution was to put an adequate power distribution system in place and they really did not want to do that. Finally, after many discussions and numerous service calls, I assembled a power distribution (PD) for them and those problems went away. They were amazed at the difference it made--electronics ran much cooler and their system had real dynamics. Simply stated, sound systems (and power amplifiers in particular) require adequate current or there will be problems like those you are experiencing.
Unfortunately, many bands dismiss implementing power distributions for a number of reasons--technical expertise in connecting them, cost, takes up more space in their truck (or trailer), cost, cost, and cost--they tend to get expensive! If there is any way possible, I would suggest that you borrow a PD (or configure your electrical power in a more thoughtful manner) to see if your heat problem goes away. If your problem is related to electrical power then adding vents and/or fans will not be a solution.
Last edited by Anthony Martin; 05-20-2014 at 08:19 AM. Reason: wanted to add a statement apologizing for the length
Anthony, thank you for taking the time to be so thorough. Your post contains many points worthy to be pondered.
Before I go into a detailed reply, my motivation for this thread was that while the S16 is warmer than I expected, I have no idea how warm the S16 usually gets; it may be that with the passive ventilation through the small slots at the side, it is normal for it to get as warm as it did. If that is a regular operating temperature for the device, I'll expect that from now on.
The obvious heat source was the sun. There were no problems with the dynamics of the sound.
My gut feeling is that power wasn't the problem. This is a small setup, putting out ~90dB SPL from each of two main speakers; I would be very surprised if the amp (which is rated at 1200W electrical) puts out more than 200W, and it remained cool. (Its -20dB light barely blinks.)
Add to that S16:45W, X32 Rack 60W, Rack DI-Box 10W, plus 4 active speakers used as floor monitors, plus one small bass amp used as monitor, plus a guitar effect, laptop, WiFi router, radio headphones (unneeded precaution). Make that 1500W on a bad day, probably considerably less. We don't have lighting. We're running off a 220V/16A power cord. (In fact, the setup usually works best when everything runs of a single outlet; using different outlets, we often pick up hum on the floor monitors.) I can tally up (or even measure) the electrical power consumption of the devices next time I'm in our practice room, but we've never had any electrical problems that I'm aware of. I could also measure the voltage at the next gig, with everything connected and running. I doubt anything abnormal will surface, but you never know.
Could the switching power supply of the amp be interacting with the power supply of the S16?