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Silver Member Username: Jwbulger79Florida Post Number: 527 Registered: Nov-04 | i'm looking to power a set of 6.5" comps with an old school Orion amp which has no internal crossovers. I will have no sub or rear speakers for a few months, but will add a mono amp and sub in the future. i'm keeping my factory head unit, and hooking up a line output converter. What would you recommend for a HPF solution for my comps? I don't mind building my own. This seems like a good resource to learn about that: http://www.the12volt.com/caraudio/cross.asp I'm thinking that when it's all said and done, my sub (probably a single 8" in sealed enclosure) should be crossed over at 80Hz w/ 12dB slope. And the high-pass filter on the comps at 100Hz w/ 12dB slope. Is that what you would recommend? In the meantime, before I get the sub, would 100Hz for the HPF be recommended, or should i go lower? slope? i'll read up more on how to build my own HPF's, but is it as simple as putting a capacitor(s) in-line with the positive speaker wires coming out of the amp? is there any disadvantage to doing this over buying an external crossover unit? I don't know enough to get crazy with EQ's and fine tuning systems, so would this be an ok solution for now? thanks! |
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Platinum Member Username: GlasswolfColumbia, SC USA Post Number: 12979 Registered: Dec-03 | use the tightest tolerance caps and coils you can get your paws on, and go with a 2nd order (12dB Q) HPF. You'll want a steeper slope for the LPF on the sub. probably 3rd order only drawbacks to passive filtering are phase shift, power loss (minimal), and the chance of inducing noise if the XO is close to the power lines for the stereo system. when building your filters, heatshrink them when done, and use good solder technique, and you'll be all set. |
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Silver Member Username: Jwbulger79Florida Post Number: 536 Registered: Nov-04 | Thanks GlassWolf! I'll build it as spec'd here...http://www.the12volt.com/caraudio/cross12db.asp and use the calculator here with 4 Ohms and 100Hz... http://www.the12volt.com/caraudio/crosscalc.asp#ccc |
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Platinum Member Username: GlasswolfColumbia, SC USA Post Number: 12984 Registered: Dec-03 | yeah by tolerance I mean you can get capacitors with a 10%, 5%, 2%, and 1% tolerance (how close to tha actual capacitance stated, they really are.) spend the extra cash and get close (high) tolerance caps and chokes. It makes for better matched filters when you build them. I had an 14 speaker setup in one of my cars that used hand made passive filters for all but the two subs. It worked well. |
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Silver Member Username: Jwbulger79Florida Post Number: 537 Registered: Nov-04 | For a 4 ohm 2nd order HPF, the calculator said i need a capacitor that is 281.31466 µfd, and a coil that is 6.36639 mHy. would this work for the caps... http://www.mouser.com/ProductDetail/Vishay/600D287G040DX4/?qs=IojMgTCMkEdaSk5vyE 3nqQ%3d%3d i wasn't able to find a coil, but i will read up more on it. anything specific to look for on those? thanks again for all the help GlassWolf. I really do appreciate it. |
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Silver Member Username: Jwbulger79Florida Post Number: 538 Registered: Nov-04 | i found this on PartsExpress.com. Do youthink it's of good quality? I can't tell what the tolerance is. http://www.parts-express.com/pe/showdetl.cfm?Partnumber=266-460 |
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Platinum Member Username: GlasswolfColumbia, SC USA Post Number: 12990 Registered: Dec-03 | the parts express filter is good. the Mouser cap won't work. you need non-polarized caps for crossovers, and those can be hard to find in small quanities. I used to use Jameco to get some parts, and PAC for others. air core coils and non polarized electrolytic caps are ideal for these things. |
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Silver Member Username: Jwbulger79Florida Post Number: 539 Registered: Nov-04 | nice. i'll just go with that then. soldering skills are a little rusty. or i could get an xtr... btw, would an xtr's 150w on those CDT 61a's be overkill? would the benefit be marginal over 75w, or would it just be badass? |
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Silver Member Username: Jwbulger79Florida Post Number: 540 Registered: Nov-04 | and thank you for the vendors and specs. |
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Platinum Member Username: GlasswolfColumbia, SC USA Post Number: 12998 Registered: Dec-03 | going from 75W to 150W would add about +3dB, which is "noticeable" but it takes an increase in power of 10X to double the audible volume, so if that gives you an idea.. I guess if you have the option to get a 2150XTR (the XTR series is what became of the SX series) then go for it.. both are great amos though, and that 275SX would do just fine for the CDTs. When I had my festiva, I used all passive filters to run a 2125SX driving 4 orion hard dome tweeters (dash) 2 orion (peerless) soft dome tweeters and 1 5" orion midrange in each front door, and two more 5" mids in the back. The hard domes were filtered @ 15KHz+ and ran @ 8 ohms. The soft domes were also @ 8 ohms, and ran 5-15KHz, while the mids ran 5K down to the subs @ 4 ohms. I had an Orion 280GX XO'ed by an Orion 200CRX electronic XO driving two Cerwin Vega LE12D 12" subs @ 2 ohms stereo @ about 55Hz down. The setup worked outstandingly. That was the car I ran in IASCA in the early 90s On a different note, try this for soldering leads of caps and coils: tin the wire lead on the cap tin the wire lead on the other cap, or coil to be joined to teh first cap. lay the two leads together, and just lightly tin the tip of the soldering pen, then touch it to the leads. the solder should flow almost instantly, and join the two wires together straight down the wires where they touch. Then just tape them up, or before joining them together, slide some heat shrink tubing in place to shrink wrap the solder point. |
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Silver Member Username: Jwbulger79Florida Post Number: 541 Registered: Nov-04 | man, that sounds like a SWEEET setup! thanks for the soldering tips. i needed that! dude, i just realized that the crossovers in the CDT-61A's have a built in 100Hz HPF. Would i even need another HPF, or could i just hook up a 275SX and be done with it? |
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Platinum Member Username: GlasswolfColumbia, SC USA Post Number: 13008 Registered: Dec-03 | just use the integrated HPF |
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Silver Member Username: Jwbulger79Florida Post Number: 542 Registered: Nov-04 | awesome. thanks Glass! |