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Author Topic: How does one inject pink noise? David E. Nedrow Master Film Handler Posts: 368 From: Columbus, OH, USA Registered: Oct 2008 posted 11-22-2010 03:51 PM                        There are test points on various bits of the USL JS 105/195 sound processor, through which one is able to inject pink noise. My question is, how does one actually do that? On visual observation, the test points look like they're single pole. If I have a pink noise generator that puts out a 0 dB signal at line level, how would I input that into, for example, the JEQ-10 house equalizer module? If the test input IS single pole, what is used for the second pole? Chassis?  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 11-22-2010 04:27 PM                     the other pole is a e terminal to one on the optical preamp is easiset to reach  |  IP: Logged David E. Nedrow Master Film Handler Posts: 368 From: Columbus, OH, USA Registered: Oct 2008 posted 11-22-2010 05:25 PM                        Thanks, Gordon.  |  IP: Logged Tony Bandiera Jr Film God Posts: 3067 From: Moreland Idaho Registered: Apr 2004 posted 11-22-2010 09:00 PM                     David, when injecting pink noise through those points be VERY careful as some of them are "post-fader" which means they will feed signal directly to the amps with no level control between! Very easy to blow out speakers if you aren't careful. USL still has their plug-in pink noise card, get it if you can, it's not expensive and provides the proper levels to set room SPL correctly.  |  IP: Logged Louis Bornwasser Film God Posts: 4441 From: prospect ky usa Registered: Mar 2005 posted 11-23-2010 03:11 PM                        You know, it might be possible to assemble an adapter card to allow this pink noise gen to work in a Dolby. Voltages and levels are probably similar. Louis  |  IP: Logged David E. Nedrow Master Film Handler Posts: 368 From: Columbus, OH, USA Registered: Oct 2008 posted 11-23-2010 04:24 PM                        quote: Tony USL still has their plug-in pink noise card, get it if you can, it's not expensive and provides the proper levels to set room SPL correctly. I've been considering that, but I'm -- hopefully -- getting a new JSD-80 to replace this poor, abused JS 105/195 that I inherited. I think there may be someone locally who has the USL pink noise card. I'm going to ask our service person if he can get in touch to see if we can borrow it for a day or two. I hate to spend $250 for something I'll probably have no need for in the near future. Though, if I somehow come up with space for a "screening" room, I could use this JS and amplifiers (being replaced as well) for that, meaning I would need the pink noise card. I hate decisions like these. And I'll check the block diagrams for the test points to see where they fall in the chain. Thanks for the warning, as it wasn't something I thought of.  |  IP: Logged Manny Knowles "What are these things and WHY are they BLUE???" Posts: 4247 From: Bloomington, IN, USA Registered: Feb 2002 posted 11-23-2010 06:25 PM                     quote: David E. Nedrow puts out a 0 dB signal 0dBFS?  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 11-23-2010 10:51 PM                     Nope...0dBv. The JS series had a buss level of .775V -Steve  |  IP: Logged Manny Knowles "What are these things and WHY are they BLUE???" Posts: 4247 From: Bloomington, IN, USA Registered: Feb 2002 posted 11-24-2010 03:38 PM                     I was gonna say... (my point being...you can't just say "dB" by itself...it's not enough.)  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 11-24-2010 05:09 PM                     It was, more or less, implied. I could understand the confusion between dBv, dBV (.775V vs 1.0V) but in no way should someone think that was dBFS  |  IP: Logged Manny Knowles "What are these things and WHY are they BLUE???" Posts: 4247 From: Bloomington, IN, USA Registered: Feb 2002 posted 11-24-2010 05:53 PM                     I guess I'm just picky about insisting on a reference.  |  IP: Logged

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