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Author Topic: Amp rack positions: top or bottom? David E. Nedrow Master Film Handler Posts: 368 From: Columbus, OH, USA Registered: Oct 2008 posted 10-17-2010 08:55 PM                        We just moved a new sound rack into the booth and I'm going to start mounting equipment. We'll have a new USL sound processor, DTS XD10, SDDS unit, 5 amps, and a huge honking UPS I have leftover from my computer days. Assuming the amps will put out the most heat -- haven't checked the specs yet -- should they be mounted up top? This rack does have a fan in the top pulling air through the unit. Having them in the top makes accessing the processors a little less convenient, but assuming they've been set up properly I shouldn't have to touch them very often. My other option is to put all of the processors in the new, enclosed rack, along with LD, DVD, and Blu-Ray players, satellite box, etc. The I would mount the new amps in the old rack. Or, just put the amps on the bottom with the processors on top in the new one. Any guidance? -David  |  IP: Logged Manny Knowles "What are these things and WHY are they BLUE???" Posts: 4247 From: Bloomington, IN, USA Registered: Feb 2002 posted 10-17-2010 09:03 PM                     if i had a choice to separate the amps, that's what i'd do. if u have a mixed rack -- one that contains your amps as well as your processors -- u want the amps on bottom for two reasons -- they're heavy so u want the center of gravity to be lower -- and also u want the processor and monitor, etc around eye-level since u handle those more in the course of a day -- the amps are turned on and left alone, so u dont really have a need to have them at operator-level  |  IP: Logged Randy Stankey Film God Posts: 6539 From: Erie, Pennsylvania Registered: Jun 99 posted 10-17-2010 09:21 PM                     So long as the amps and all the other equipment have sufficient air flow, I don't think it matters much. Most amps I have seen, lately, have fans that draw air horizontally, across the components, usually in the front and out the back. Don't block the air ducts. Keep the filters clean. Don't let wires and junk pile up around the top and bottoms. Make sure the racks, themselves have enough air vents to let the air out. After that, I don't see much that will cause problems. Assuming ventilation and cooling are taken care of I think you can let design considerations be the main factor in locating equipment.  |  IP: Logged Louis Bornwasser Film God Posts: 4441 From: prospect ky usa Registered: Mar 2005 posted 10-17-2010 09:26 PM                        Avoid the bottom 7 inches of the rack for any use. That's where the dirt is and you don't want the amp-fans to inhale the sweepings. Louis  |  IP: Logged Sam D. Chavez Film God Posts: 2153 From: Martinez, CA USA Registered: Aug 2003 posted 10-18-2010 01:11 AM                       I agree with Manny and Louis but you should leave room at the very bottom for the amps yet to come 9.1, 11.1, 13.1, 15.1. Also, leave some room in the middle as well for the future.  |  IP: Logged Richard Hamilton Phenomenal Film Handler Posts: 1341 From: Evansville, Indiana Registered: Jan 2000 posted 10-18-2010 05:56 AM                     Here is a pic of a rack I did about 10 years ago, no problems with the amps. I was cramped for space and had to stack the amps. This is a planetarium and I had another small rack in the console at the back of the auditurium. Here is a typical rack layout that I did. The Dolby is placed at eye level. Rick  |  IP: Logged Manny Knowles "What are these things and WHY are they BLUE???" Posts: 4247 From: Bloomington, IN, USA Registered: Feb 2002 posted 10-18-2010 06:00 AM                     yeah, i'd say that's about what i'm used to seeing -- where's that planetarium? -- i've never been to one who's still using the fostex 24 track recorder?  |  IP: Logged Richard Hamilton Phenomenal Film Handler Posts: 1341 From: Evansville, Indiana Registered: Jan 2000 posted 10-18-2010 06:33 AM                     Manny, The planetarium is here . I know I've posted pics on here before. The other rack layout is at an amusement park in China. movie wonderland . I installed 3 systems there. They use the Fostex as the primary sound source. The soundtracks come on tape and are recorded onto the Fostex. The Tascam is used as a back-up if needed. They chase timecode generated by the projector. These are all MegaSystems 8/70 projectors. Rick  |  IP: Logged Samuel Hynds Film Handler Posts: 50 From: Riverside, CA, USA Registered: Aug 2004 posted 10-18-2010 10:43 AM                     Would put processor at eye level & amps below. Just don't put the amplifiers on the UPS - it could starve the power supply when the sound track gets busy.  |  IP: Logged Monte L Fullmer Film God Posts: 8367 From: Nampa, Idaho, USA Registered: Nov 2004 posted 10-18-2010 08:02 PM                     ..UPS the processor instead since they do contain memory that could be erased on accident - which I've seen and done with CP500's.  |  IP: Logged Tom Sauter Expert Film Handler Posts: 163 From: Buffalo, NY, USA Registered: Sep 2000 posted 10-19-2010 10:53 AM                        Amps at the bottom makes delivery and setup of prewired racks much less complicated as top-heavy racks can be dangerous to maneuver. Heat dissipation is not just about where the devices are installed in a rack, its about proper airflow management. Middle Atlantic has an excellent whitepaper on the topic  |  IP: Logged Scott Norwood Film God Posts: 8146 From: Boston, MA. USA (1774.21 miles northeast of Dallas) Registered: Jun 99 posted 10-19-2010 11:51 AM                        One thing that I would like to see in more cinema racks is a power sequencer or other method to ensure that the amps are powered on last and powered down first. Older processors (at least CP50 and CP200) make nasty pops at powerup, which can easily blow speakers if the amps are powered up first. As an operator, I generally prefer racks that are in this order (top to bottom): - power distro/sequencer(s) (alternatively, this can live in the bottom space) - CD player (for non-sync) - DA20/DTS/SDDS unit - cinema processor (at more-or-less eye/shoulder level) - booth monitor - mixer for guest inputs/microphones/etc. - guest inputs - other stuff that doesn't normally require operator attention (e.g. crossovers, microphone preamps, etc.) - amps - power distro/sequencer(s) (if not at top) Having the processor at eye/shouler level is less necessary if remote boxes for format and fader setting are installed on the front wall of the booth (which almost no one does, for some reason). Conceptually, I prefer to have video stuff go in a separate rack from cinema sound equipment, but lots of installations seem to commingle the two systems. This will result in some messy-looking racks in a few years when the video equipment gets upgraded. The only sound rack that I have wired from scratch is for my home system, and it consists mostly of scavenged equipment. It is semi-portable (it's a 20-space Anvil rack case with wheels), and the amps pretty much had to be at the bottom for stability. The exercise gave me an appreciation for the art involved in putting together a well-designed sound rack, with consideration given to electrical, mechanical, servicing, and human-factors issues. Here's a shot from the picture gallery (we used this for a video setup at a festival): from top to bottom: CD player custom rack panel to toggle between decoded non-sync and L/R non-sync (for video) processor monitor guest inputs/outputs microphone preamp amps  |  IP: Logged Jeffry L. Johnson Jedi Master Film Handler Posts: 809 From: Cleveland, Ohio, USA Registered: Apr 2000 posted 10-21-2010 12:26 PM                        If there's room place a filtered blower in the bottom, below the amplifiers. McLean Cooling Technology standard packaged blower web page  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 10-21-2010 01:40 PM                     In wall mount racks i put the processor at the bottom since heat rises in floor racks i put the amp s at the bottom with a signal path flowing down the rack i also preferr fan cooled that is like QSC back to front so it doesn't heat up the interior of the rack  |  IP: Logged

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