need advice for subwoofer upgrade

D

destroyer159753

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Mar 16, 2003
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(note: This is the old plan but contains elements that will be used in the new plan)

Hi, I want to add on another subwoofer to my home system which attaches to my computer. Right now I have a 10" rockford fosgate sub hooked up to the z-560 amplifier which supplies 188 watts to the sub. I'm thinking about getting this amplifier: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3073616887&category=14973 and hook it up to some 500 rms 1000 peak sub which, i havent decided which.

the connections: the amplifier uses standard speaker wire to connect to the subwoofer on both ends i believe. I plan to split the wire by cutting a standard rca and hooking the raw end to the amplifier, and then hook a 2 rca splitter to the rca end, then one split of it will be raw speaker wire to the subwoofer, and the other split will be either speaker wire or rca depending on what the new amp likes.

my questions are:

1. will things work, also as in will my old amp working as a preamp (i think, right?) make everything work and not screw up.

2. will it be a good setup

3. recommendations for anything including subwoofer, wiring, or any changes.

Thanks
 
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new changes: i now plan to split a 1/8 coming from front line out on soundcard, one split goes to amp 1, the other split goes to amp 2, and i plan to get probably a 12" 400 rms 800 max sub because i hear underpowering it is worse than overpowering, well i will probably try to get a 450 rms 900 max, that would be even better. the amp doesnt say rms, but most likely says peak, and rms is a little less than half so im thinking it would be 425 rms power from sub.
 
Couple of concerns:

That amp doesn't have a low-pass filter, so you'll either need to buy or build a crossover or put coils on the output. The crossover is harder to design from scratch (but you can buy them too) but won't sap as much power as the coils will. You'll need to pay close attention to the slope of the cutoff (how fast will it attenuate the higher frequencies) or you'll get the world's loudest Charlie Brown Adult noisemaker.

As to your old amp acting as a preamp, are you referring to a reciever or an actual amp? A reciever would work fine with a 1/8 to RCA cable, so you'll be fine there.

RMS ratings are usually fishy in the audio world, so take them with a grain of salt. I wouldn't sweat the 50 watt difference much - just watch the level of the bass and when you hear it distort, mark the volume knob and stay below that. Sealed boxes can help with overdriving problems to some extent, but box design is a whole different thread. You're right on the underdriving - square waveforms are evil.
 
yeah, i recently realized i need to get a low pass filter too. one thing that im curious about crossovers is that they say their wattage rating, what the hell? if i have the filter between the sound card and the amp, i wont have to worry about wattage right, because the amp would supply the wattage to the sub, and wattage rating is only important when you have it between amp and sub, right. how cheap can i get a ac current crossover with fairly good low response that will get the job done?
 
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WTF are you even thinking about buying that POS amp for use with a subwoofer?
Buy the right amp for the application and you wont have to worry about things like voltage ratings on the caps. Here is a good example of a nice Plate amp----->
http://www.partsexpress.com/pe/pshowdetl.cfm?&PartNumber=300-794&DID=7
Dont even get me started about using low quality, overpriced "car audio" components and radio shack crossovers. :rolleyes:
But then again I would just buy a nice kit like this------>
http://www.partsexpress.com/pe/pshowdetl.cfm?&PartNumber=300-760&DID=7
lets add it up.... that comes to 295$ for the amp and sub you picked out.
But you will still need a crossover, dampening material, and a cabinent. On the other hand you can pay 349$ (plus shipping) for a package that has everything.
Its a no brainer.
 
If you are dead set on that whole ebay thing check out this item ;)
 
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