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Author Topic: Surround speaker wiring Sam D. Chavez Film God Posts: 2153 From: Martinez, CA USA Registered: Aug 2003 posted 02-01-2010 08:49 PM                       I'm humbled by having Steve Guttag agree with me. My life is now complete.  |  IP: Logged Sean McKinnon Phenomenal Film Handler Posts: 1712 From: Peabody Massachusetts Registered: Sep 2000 posted 02-02-2010 12:33 PM                        Thank you guys, What you say makes perfect sense!  |  IP: Logged Tony Bandiera Jr Film God Posts: 3067 From: Moreland Idaho Registered: Apr 2004 posted 02-02-2010 04:57 PM                     quote: Paul Mayer Doing series or series/parallel plays havoc with damping and phase issues. While the damping could be a (minor) issue for surrounds I don't think the phasing issues matter at all, especially since you are NOT supposed to be able to locate surround information to any given individual speaker (or point source if you prefer), in fact it is remotely possible the phasing effect could enhance the surround field. quote: Paul Mayer ....Also, if you have enough cable, home run 'em, that is run each speaker's feed back to the rack. Makes it much easier to work on things later on. And even if you don't have enough cable, go buy more and home run those speakers!! If a speaker is ever blown out, it makes it easy to bypass/disconnect without having to take speakers down. Any installer who doesn't home run those lines is a hack and not worthy of being called professional. quote: Sam D. Chavez I'm humbled by having Steve Guttag agree with me. My life is now complete. LOL That's one sign of the apocalypse!! (Steve agreeing with Sam that is..)  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 02-02-2010 05:57 PM                     That is not true...I agree with well over 95.83% of what Sam says.  |  IP: Logged Phil Hill I love my cootie bug Posts: 7595 From: Hollywood, CA USA Registered: Mar 2000 posted 02-02-2010 06:01 PM                  I always agree with 98.6% of what Sam and/or Steve sez...unless I have a fever.  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 02-03-2010 01:21 AM                     Tony said "I don't think the phasing issues matter at all, " hmm phasing is probably the single most important issue in designing a good surround coverage pattern  |  IP: Logged Tony Bandiera Jr Film God Posts: 3067 From: Moreland Idaho Registered: Apr 2004 posted 02-03-2010 10:48 PM                     Gordon, I am referring to the very subtle shifts that MIGHT be introduced by the series connection of the speakers. Obviously a deliberate out-of-phase connection of any part of the surround array will introduce problems. Methinks you sometimes read more into posts than what is meant. I stand by my theory that any phase shifts from the series connection of the speakers is NOT detrimental and can, given the right conditions, actually enhance the idea of a diffuse sound field that is the intention of a surround array.  |  IP: Logged Scott Norwood Film God Posts: 8146 From: Boston, MA. USA (1774.21 miles northeast of Dallas) Registered: Jun 99 posted 02-04-2010 08:49 AM                        It still seems to me that a 70v system would solve all of the above-mentioned issues. It also makes the math easier, reduces wiring costs, and can make it easier to meet some electrical codes. Yes, I know that this has been discussed before and, yes, I know that it isn't very popular in modern cinema systems due to the cost of the transformers.  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 02-04-2010 10:38 AM                     No I was not reading more in Serries/Parrallel is in my book fine and I also home run everything but that said my biggest issue is usually with phase issues due to delays from bad placement The big issue with 70v is it is expensive to do right  |  IP: Logged Gordon Bachlund Jedi Master Film Handler Posts: 696 From: Monrovia, CA, USA Registered: Aug 1999 posted 02-04-2010 11:50 AM                        Gord is quite correct. The speed of sound (1,125 feet/second at sea level) must be considered in speaker placement. As the speed of current flow in copper conductors is about 186,000 miles per second, the method of circuitry is immaterial.  |  IP: Logged Sean McKinnon Phenomenal Film Handler Posts: 1712 From: Peabody Massachusetts Registered: Sep 2000 posted 02-04-2010 02:23 PM                        The North Conway Twin in North Conway N.H. uses a 70 volt system for the surrounds. As I recall that was the ONLY theatre in my service territory that did  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 02-04-2010 02:37 PM                     70v is expensive if one wants to buy quality transformers that will have a decent frequency response and powerhandling One can buy new amps for less  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 02-05-2010 09:45 AM                     70V also can actually ADD to one's electrical code issues as 70V is not considered low-voltage. With amps capable of driving 2-Ohm or less, well, the desire for 70V or similar constant voltage system diminishes. With QSC's DCA 1222 able to drive 5 speakers on each channel...again, the desire for 70V diminishes to about zero as the sound quality will likely be higher on the 5-paralleled speakers. Steve  |  IP: Logged Jonathan Bodge Film Handler Posts: 83 From: East Dorset, VT Registered: Nov 2006 posted 02-05-2010 09:36 PM                     Agree, I usually put the softer speaker up front in this situation.  |  IP: Logged Louis Bornwasser Film God Posts: 4441 From: prospect ky usa Registered: Mar 2005 posted 02-06-2010 06:47 AM                        A "quick" measure of a power amp and its overall quality is whether or not it has a seriously good power rating at 2 ohms. Good amps do and bad amps do not. I have personally driven 8 JBL 8330 on a string across one amp output times 6 for a one-night rental (48 speakers). As regards series parallel; National Amusements for years used 7 speakers for sides. 4 in parallel, 3 in parallel, then series for the 4 and 3. We put the loud 3 in front where they could better compete with the louder screen speakers. I only use Ashly FTX 2000 amps. Louis  |  IP: Logged

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