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Author
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Topic: Simplex crossover and connection help...
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analog addict
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posted May 09, 2008 01:22 PM
Got a question or two about the crossovers and connections on my W's. I finally found a little bit of time and took one of the crossover boxes apart, or as far apart as I could get them. I was told that these speakers may have had a box in the control room that allowed for remote cap changes. However, I got to the point of trying to open the lid on the crossover, and I couldn't get it open due to the wiring preventing more thsn just cracking it open and peering inside. However, I saw some big metal cans inside, and thought that they may be some sort of oil filleds. 
My question becomes, how best to wire these up to get the most out of them. The crossover box has the terminals marked "strap for 2 H.F. units" and I was thinking I would like to try wiring the 288-16G's/203b's to these connections, and then rewiring the connection marked "H.F. Attenuation db" to -4 db from -1 db where it currently resides. Do any of these changes seem unreasonable or potentially hazardous to the gear? As an initial step, I was thinking about wiring in a junk driver to the 2nd H.F. connector to start with, and seeing how that driver responded, and then trying the -4db terminal next before putting in the 2nd set of 288's. Would the -3db change in high freq loudness make up for the extra driver? Anyone have any thoughts or suggestions??? Thanks..... -------------------- Cheers! Analog Addict Jack of all Trades, Master of None
Searching for Sonic Nirvana... 
My alter ego...
 Time is an abstract concept created by carbon-based life-forms to monitor their ongoing decay. -Thunderclese
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Posts: 41 | From: Raleigh NC | Registered: Aug 2007 | IP: Logged | Problem w/ Post?
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bfish
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posted May 09, 2008 11:06 PM
The remote changeover box I mentioned earlier was strictly for house equalization and channel switching, it had nothing to do with the crossover.I don't remember now what horns/drivers your setup had originally, but the wiring would have likely been correct for that setup. All driver connections should be made only on the bottom row of terminals. DON'T connect drivers to the "strap" terminals. Those terminals are only to be used (connected only to each other = "strapped") if you are using an 8 ohm HF load (dual 16 ohm HF drivers in parallel, or a single 8 ohm driver). The choice of which "HF Attenuation" terminal to connect one of the HF leads determines the relative HF loudness, and only one of them should be connected. The lower the -dB number, the louder the HF. Yes, if you use 2-16 ohm hf drivers, rewiring for -3dB more attenuation will yield the same overall HF output as a single would before the rewire. Therfore, you gain nothing but 30+lbs per side. Unless the drivers and diaphragms are well-matched pairs, 2 might even sound worse than one.
[ May 09, 2008 11:09 PM: Message edited by: bfish ]
-------------------- bfish "We're going ALL the way, till the wheels fall off and burn!"
Bob Dylan/"Brownsville Girl"
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Posts: 1672 | From: Arkansas | Registered: Dec 2004 | IP: Logged | Problem w/ Post?
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analog addict
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posted May 11, 2008 12:44 PM
quote:
Originally posted by bfish:
The remote changeover box I mentioned earlier was strictly for house equalization and channel switching, it had nothing to do with the crossover.I don't remember now what horns/drivers your setup had originally, but the wiring would have likely been correct for that setup. All driver connections should be made only on the bottom row of terminals. DON'T connect drivers to the "strap" terminals. Those terminals are only to be used (connected only to each other = "strapped") if you are using an 8 ohm HF load (dual 16 ohm HF drivers in parallel, or a single 8 ohm driver). The choice of which "HF Attenuation" terminal to connect one of the HF leads determines the relative HF loudness, and only one of them should be connected. The lower the -dB number, the louder the HF. Yes, if you use 2-16 ohm hf drivers, rewiring for -3dB more attenuation will yield the same overall HF output as a single would before the rewire. Therfore, you gain nothing but 30+lbs per side. Unless the drivers and diaphragms are well-matched pairs, 2 might even sound worse than one. [ May 09, 2008 11:09 PM: Message edited by: bfish ]
Well, I am kinda interested in playing with my selection of drivers, including switching between horns and large and small format drivers. I have the original 288B's and 1005B's, a set of 291-16B's now reworked as 288-16G's that came with a pair of 203B's, a set of 16 ohm 806A's with 511's and a set of 802-8G's still sitting in my Model 19's. I also have a just arrived set of 1" to 1.4" throat adapters. I'm not sure I'm going to got to the trouble of pulling the 802's anytime soon, but I'd like to switch the other driver and horn sets around as able and just experiment with the sound a bit. Now if I was going to run two sets of these 16 ohm drivers, would I then connect the 2 "strap" terminals, and then just connect both sets of HF drivers to the same "com" and "HF attenuation" terminals, effectively wiring them up in parallel?
I'm sure there might be opinions on what others have experienced before, but this is a chance for me to compare drivers on a more or less even playing field. (hopefully) Yesterday a buddy of mine from AK came over and we broke out the W's. We did hook up one 288-16G and one 288B to the two 10 cells, and the 288B was clearly better in high frequency extension. The 16G's sounded almost muffled in comparison. I don't know if that's the way they spec out, but that's what we heard. I'm also wondering if it's due to the way the crossovers are set up... Any guesses?
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Posts: 41 | From: Raleigh NC | Registered: Aug 2007 | IP: Logged | Problem w/ Post?
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