wcbjr Posted March 17, 2006 Share Posted March 17, 2006 Although, it doesn't say much about driving a single coil being damaging. What about driving just a single coil, and leaving the other open? Well, as you would guess, the push is weaker. The system has a peakier resonance (for the techie types, Qts increases because Qes increases). BUT - let's drive one coil, and short the other. I forgot what I was supposed to remember. Link to comment Share on other sites More sharing options...
Boulderguy Posted March 17, 2006 Share Posted March 17, 2006 Great article! Quote (this is totally new to me): "What about driving just a single coil, and leaving the other open? Well, as you would guess, the push is weaker. The system has a peakier resonance (for the techie types, Qts increases because Qes increases). BUT - let's drive one coil, and short the other. Guess what? Things change from the original (both coils driven) situation, but they also stay the same. The driven voice coil is pushing and pulling, as normal. But what about the shorted voice coil? Well, it's trying to keep things at rest - it's trying to resist ANY motion! The net result is the overall peakiness of the resonance is the same as it was when both coils were driven, even though we are only using half the motor (driving one coil). The other coil helps "tame" the driven coil, so that the system basically behaves the same as before. Say you want to use our Shiva driver. Say you like everything about it (especially the massive Xmax!), but for your intended application, you want a higher Q. Well, this is the way: drive one voice coil. But rather than just shorting the second coil, or leaving it open, terminate it with a resistor. The result? The Qts of the driver will change from the open to the shorted Qts as the resistance is decreased. That means you can tune the Q of the driver, with nothing more than a potentiometer!" This is really MS's terrain - it's his gear. But what this is saying is you can wire the DVC - 2ohm using only a single VC & short the other two together for a 2 ohm load with no ill effects or power loss. You could even add an adjustable knob to vary the resonant (loudest) frequency. Cool beans - turns out I don't know everything after all - - who knew? Link to comment Share on other sites More sharing options...
msmith Posted March 17, 2006 Share Posted March 17, 2006 You won't break the speaker by running only one coil, but you are radically altering its operating parameters. With only one coil connected, the motor woofer's motor force is cut in half and the Q goes way up which messes up the recommended enclosure applications and throws all the parameters out of whack. Read all about DVC woofers here: http://mobile.jlaudio.com/support_pages.php?page_id=163 You need a dual 4 ohm with coils wired in parallel or you can run the dual 2 ohm wired with coils in series. Link to comment Share on other sites More sharing options...
rtp Posted March 18, 2006 Author Share Posted March 18, 2006 Ok, what the installer said (or I heard) and what I've got were two different things. I've got the D4. The sub he just replaced was a D2. Whew... glad that is settled. So, how do you tune a custom FB box? Why would things start to sound muddy when I turn the gain up much past dead center? Link to comment Share on other sites More sharing options...
jim malach Posted March 21, 2006 Share Posted March 21, 2006 I have been running into front imagine problems up front but back to my real question I am running 2 jl amp 1 1/1000&1 4/450 with 0 gauge and 200 amp jl fuse ohio alternator and two caps and it's an 5eat I told them that they had to upgrade the grounding system in the car because when the music is kicking my trans is messing up bad so there going to go with 2 gauge grounding kit one to the chassis one to the alternator one to the engine and on to the trans should this stop the bucking oh yea forgot about the yellow top do you think any other wires you know would be a great help Link to comment Share on other sites More sharing options...
PGT Posted March 21, 2006 Share Posted March 21, 2006 So, how do you tune a custom FB box? Why would things start to sound muddy when I turn the gain up much past dead center? gain isn't a technically volume knob....it's to match the input voltage the amp sees upstream. There's a point where your amplifier reaches it's max headroom capability - you never want your gain set past that. Seems like you found out the limitation of the amp. Link to comment Share on other sites More sharing options...
msmith Posted March 21, 2006 Share Posted March 21, 2006 Jim, What size alternator is that Ohio Generator unit? Are you sure it's working properly? The key wires are: Battery ground Alternator or engine ground strap Alternator pos. feed to battery You may also need to augment your chassis ground in the back with another connection and you need to make darn sure you've got a really solid, clean ground connection... are you using the JL Audio grounding lug? Link to comment Share on other sites More sharing options...
jim malach Posted March 22, 2006 Share Posted March 22, 2006 the ohio generator is 160amp and thanx fo rthe other info I will make sure that it get done 4th time around going to this guys hope I don't have to take them to court I just wish I was not so far away from my other option to take it to goodmans audio 35 year in the car audio field. Link to comment Share on other sites More sharing options...
Sponge Posted March 31, 2006 Share Posted March 31, 2006 Did/do you have any heat issues w/the amp covered in spare tire comparment? I have an old A404.2 that I will be using and was planning on a side of the trunk mount but might try that first.... My vB Gallery Link to comment Share on other sites More sharing options...
rtp Posted March 31, 2006 Author Share Posted March 31, 2006 I've had no problems at all with heat. Although, it isn't really warm out yet... we'll see what happens when it's 95 out! Link to comment Share on other sites More sharing options...
fweasel Posted April 1, 2006 Share Posted April 1, 2006 I've had no problems at all with heat. Although, it isn't really warm out yet... we'll see what happens when it's 95 out! Me too, I have a similar set-up. I think the additional volume of air in the tire well helps also. My amps don't get much above warm, but we'll see this summer. If need be, I'll just install a vent, something similar to Manville's. ignore him, he'll go away. Link to comment Share on other sites More sharing options...
Boulderguy Posted April 2, 2006 Share Posted April 2, 2006 You can always vent it if necessary. I vented mine with two fans & have had no problems - these are particularly hot-running amps. Most people have left it closed with no trouble. I guess what I'm saying is I'd start with it not vented & adapt if necessary. Link to comment Share on other sites More sharing options...
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