Return-Path: X-Processed-By: Virex 7 on prxy.net X-Real-To: stagecraftlist [at] theatrical.net Received: by prxy.net (CommuniGate Pro PIPE 4.2.6) with PIPE id 10426606; Sat, 25 Dec 2004 03:01:17 -0800 X-ListServer: CommuniGate Pro LIST 4.2.6 List-Unsubscribe: List-ID: Message-ID: From: "Stagecraft" Sender: "Stagecraft" To: "Stagecraft" Precedence: list Subject: Stagecraft Digest #238 Date: Sat, 25 Dec 2004 03:01:01 -0800 MIME-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1" Content-Disposition: inline X-Spam-Level: X-Spam-Checker-Version: SpamAssassin 3.0.1 (2004-10-22) on prxy.net X-Spam-Status: No, score=-5.3 required=5.0 tests=ALL_TRUSTED,AWL,BAYES_00 autolearn=ham version=3.0.1 X-TFF-CGPSA-Version: 1.4f2 X-prxy-Spam-Filter: Scanned For info, archives & UNSUBSCRIBE, see --------------------------------------------------- Stagecraft Digest, Issue #238 1. Re: Snow Machines by "Josh Wirtz" 2. Re: "at LEAST an ATF permit" by CB 3. Re: DMX512 Question (long) by Mitch Hefter 4. Re: How much does scrim stretch? by MPTecDir [at] aol.com 5. Re: How much does scrim stretch? by James Feinberg 6. Re: How much does scrim stretch? by Bill Sapsis *** Please update the subject line of your reply to use the subject *** line of the message you are replying to! Please only reply to *** one message subject in each reply. ---------------------------------------------------------------------- Message-Id: Date: Fri, 24 Dec 2004 09:20:27 -0600 From: "Josh Wirtz" Cc: snowmaster [at] mindspring.com Subject: Re: Snow Machines Brandon, I have worked with snow machines from several manufacturers and have only had one company provide a machine that did not leak. Snowmasters not only provides machines that work and have a lifetime warrantee, but they have incredible service. They cost more than competitor's models, but if you have a problematic machine, they will send you a new one. Things to keep in mind about snow machine operation: Keep your nozzles clean, keep the fan running after you turn the pump off until no more snow falls - this cleans the solution out of the nozzle, and keep the pumps properly primed during storage - do not let your pumps dry out. Francisco Guerra at Snowmasters can address your individual needs. www.snowmasters.com Josh Wirtz Auditorium Technician Stillwater School District/ISD 834 I am sick and tired of dealing with hit or miss snow machines. Either too much snow, or not enough snow, either covers too great of an area or not enough of an area. I need to be able to control the size of the flakes, the rate at which it falls, and the area it covers, hopefully it will be relatively quite too. Any ideas, what do you like? ------------------------------ Message-Id: <3.0.6.32.20041224115722.0180a7b8 [at] pop.west.cox.net> Date: Fri, 24 Dec 2004 11:57:22 From: CB Subject: Re: "at LEAST an ATF permit" >we've probably all got files somewhere. I >figure mine will be boring reading for someone 50 years from now: "She went to >college a lot, got married, had a kid, drank rarely, laughed often, loved music >and theatre, opened a small business to make ends meet, and shared her >knowledge with others." Riiight. It will more than likely read: Suspiciously long and varied college carreer. Studies included too much chemistry and political material. Subversive associate, progeny and legal ties as cover. Subject drinks, suspicions of illegal narcotic use (this is a standard phrase for anone that thinks and laughs often, Kristi, not a personal attack. Think of it as a compliment...). Associated far too frequently with 'artist' types and other miscreant undesirable socialists. Started a small cover operation to disseminate propganda and thought-crimes. Chris "Chris" Babbie Location Sound MON AZ Delete key training and post trimming done by appointment. Rates negotiable, will trade for typing lessons/ADD treatment... ------------------------------ Message-Id: <6.1.0.6.2.20041224121831.02cc1d70 [at] mail.DesignRelief.com> Date: Fri, 24 Dec 2004 13:30:22 -0600 From: Mitch Hefter Subject: Re: DMX512 Question (long) In-Reply-To: References: At 05:00 AM 12/23/2004, Greg Persinger wrote: >Mitch, we don't know each other so I say this so there is no >misunderstanding and you don't feel as though I am trying to pick a fight, I >would like to hear your perspective on this as you sit on the USITT DMX 512 >subcommittee. I know you're not picking a fight. There are multiple opinions out there based on multiple experiences. There is always some disagreement. I want to make sure we all have the best info to make the best decisions. >In your opinion, other than pin 4 and 5 not being connected, how are the >DMX rules being bent and broken? OK, it's an opinion (which I share with lots of people). DMX512/1990 says: 9.0.2 CONNECTOR PIN DESIGNATION Connector Pin Designations shall be as follows: PIN 1 - Signal Common (Shield) PIN 2 - Dimmer Drive Complement (Data 1 -) PIN 3 - Dimmer Drive True (Data 1 +) PIN 4 - Optional Second Data Link Complement (Data 2 -) PIN 5 - Optional Second Data Link True (Data 2 +) 10.0 CABLE Cable shall be shielded twisted pair approved for EIA-422/EIA-485 use. Examples of suitable cables are: Belden 9841 Alpha 5271 (one pair, no spares provided) Belden 9842 Alpha 5272 (two pairs, one as a spare) In my mind (no wisecracks please), this says that if you put 2 pairs in, you wire them. The PLASA/USITT Recommended Practice for DMX512 echoes my belief. The RP also recommends the use of 2-pair (or more) cable in permanent installations. The current draft of the Portable Cabling Standard for DMX512 systems (BSR E1.27-1) also says 2-pair cable (obviously subject to change as it is a draft). As Karl Ruling pointed out in Friday's digest, there are a number of manufacturers implementing the second pair and uses for it, although not necessarily well documented. Most are incompatible with each other, but as long as they are EIA-485 data, no damage would occur. If you don't have 2-pairs "in the wall" you can never make use of the potential. As for the "In/Out" method - while it may be compliant with the standard, I don't believe it is in the spirit of the standard, and your growth potential is lost. Also, unless you use the "pass-thru" method that Ken Romaine describes in Friday's digest (or some of the buffered products described in an earlier digest), you are likely causing problems with the EIA-485 data link. This data link is to be one single line, terminated at each end. Any "taps" in the middle are limited to just a few inches, and devices on these taps are not terminated. This is not because DMX512 says so, it's physics and described in EIA-485-A (the physical basis of DMX512) and its accompanying Telecommunications Systems Bulletin TSB-89. These say daisy-chain -- Star, Tree, and Branch configurations are not OK. Short stubs are OK (and are discussed) - "short" being the key word. For example, lets' look at an input connector at one end of the line (the booth), another in the middle (house tech position), and the other end at the dimmer rack (with its built in termination). When the console is plugged into the booth, you have one transmission line with termination at both ends. If you plug the console in at the tech position, which is using a single connector (not a pass-thru design), you now have termination in the middle of the line and at one end, and a nice noise antenna from the tech position to the booth. As we've noted before, DMX512 is very forgiving and sometimes this noise won't affect the system, but you have no guarantee that the extra reflections on the line won't corrupt the signal and give you a disco effect when you want a slow sunset fade. (If your console lets you "un-terminate" it, you could put a termination plug in the booth and everything would be fine. However, most consoles do not give you that option.) For a more technical discussion on EIA-485, I would defer to others of the DMX512 Task Group. I am summarizing what I have learned from the beginnings of the standard back in 1986 and the 6 plus years of the revision process we just completed. DMX512 works, and when you don't take shortcuts, it is solid and works well. Happy holidays, . . . ------------------------------------------------------------------------ Mitch Hefter mitch.hefter [at] DesignRelief.com ESTA / USITT DMX512 Revision (ANSI E1.11) Task Group Chair USITT Engineering Vice-Commissioner, DMX512 Subcommittee Chair Office: Entertainment Technology / a Division of the Genlyte Group mhefter [at] genlyte.com +1-214/ 647-7880 x 7967 (Direct Line 214/ 647-7967) +1-214/ 647-4738 Fax http://www.etdimming.com http://www.lolcontrols.com http://www.vari-lite.com http://www.genlyte.com ------------------------------ Date: Fri, 24 Dec 2004 16:09:26 -0500 From: MPTecDir [at] aol.com Cc: mfpowers [at] theater.umass.edu Subject: Re: How much does scrim stretch? Message-ID: <1DA75075.0229C9BB.00740ECC [at] aol.com> "Frank E. Merrill" writes: << I need to sew a sharkstooth scrim ......... How much should I allow for the stretchy nature of sharkstooth scrim? .......... >> Frank, Bill's advice is on the money. Having done this once myself, I would also advise you to have 3" to 4" of chain between the top webbing and the carriers. The scrim will continue to stretch over time and the chain will allow a bit of adjustment as needed. -- Michael Michael Powers, Technical Director U Mass Amherst, Dept of Theatre 112 Fine Arts Center West 151 Presidents Drive Ofc 2 Amherst, MA 01003-9331 Phone: 413-545-6821 Fax: 413-577-0025 http://www.umass.edu/theater/ mfpowers [at] theater.umass.edu mptecdir [at] aol.com ------------------------------ In-Reply-To: References: Message-Id: From: James Feinberg Subject: Re: How much does scrim stretch? Date: Fri, 24 Dec 2004 13:15:40 -0800 What about a scrim on a working lineset with a bottom pipe? Should I be flying it in to the deck each night to prevent stretch instead of flying it out to prevent damage? --jamesf On Dec 23, 2004, at 3:04 PM, Bill Sapsis wrote: > Frank. Scrim tends to stretch as much as it is allowed to. Keeping > the > weight down by using jack chain in the bottom is a good idea. I'd > hang it > about 1.5" above the deck. It will probably stretch that much, hit > the > deck and then stop. ------------------------------ Date: Fri, 24 Dec 2004 22:20:40 -0500 Subject: Re: How much does scrim stretch? From: Bill Sapsis Message-ID: In-Reply-To: on 12/24/04 4:15 PM, James Feinberg at feinberg [at] sandiego.edu wrote: > What about a scrim on a working lineset with a bottom pipe? Should I > be flying it in to the deck each night to prevent stretch instead of > flying it out to prevent damage? Back in the day......I normally did not store a scrim in the air. Up for a show and then down and into it's storage hamper/bag, whatever. If you have to leave it in the air for long periods of time I would pull the pipe. But pulling the pipe means it will float around more when the HVAC goes on and it might snag on something. Many scrims have a chain in a pocket in addition to a pipe pocket. Does yours? And why are we having this discussion on Christmas eve? Be well Bill www.sapsis-rigging.com 800.727.7471 800.292.3851 fax 267.278.4561 mobile We stand behind, and under, our work. ------------------------------ End of Stagecraft Digest #238 *****************************