so i removed the 12's from the hyundai....got a good deal on a jbl p1022 in a 3cft tuned at 30hz for $100 new from my cousin... i am amazed that this sub hits just as loud as the 12" but cleaner...but since it is a 2ohm dvc and im using an alpine mrp-m450 to push it...im only running one coil in order to get 2ohms from the amp to meet the 400rms the sub is rated at....anyone ever hear of a sub being damaged after running one coil for a while?? my cuz says it shouldnt hurt it and he knows his audio...did he just tell me that to make a sale? can this sub be affected by this method?? i hope to have pics of the setup in this car soon as it is a lot nicer lookin than the stuff i have in my truck...heres a link to the sub
http://www.jbl.com/car/products/product_detail.aspx?prod=P1022&Language=ENG&Country=US&Region=USA&cat=SUB&ser=POS
heres the specs on the amp.
http://www.alpine-usa.com/US-en/products/product.php?model=MRP-M450&lang=en&tab=F
Replies (3)
swez on 09/30/2007 16:24:11
Nice score trunk! Glad you asked before taking the plunge and frying the sub.
RDO is a possible option here. This is when one uses a variable resistor across the unused coil set. It has to be "tuned" as there is always an electrical voltage passing through the passive coil. (Reverse EMF) The variable resistor absorbs "R-EMF" and can be used to tune the "Q" of a sub when a variable resistor is used. (Low power resistor is OK here too)
The sub is rated at 200 Wrms/coil. If you run one coil here, you will risk frying the coil if pushed much above 250 continous watts RMS. To be on the safe side, I would recommend wiring this sub at 4 ohms.
This sub is very efficient in a ported box and the high sensitivity will still give you solid bass. The SPL difference at 220 vs 400 watts is only 3dB less and absolutely safe for the sub and amp.
Swez
trunkisloud on 09/30/2007 17:31:29
word...makes sense to me ...except what is rdo....and emf...whats the meaning behind this madness./?? and so the only reason that it would hurt the sub is the power rating on the coil?
swez on 10/1/2007 10:04:13
EMF is short for Electro-Magnetic Force. In a nutshell, whenever we have a coil of wire in close proximity to a magnetic field, electrical energy is created. (Voltage and a limited amount of Current too)
In this case, the sub has 2 coils. If one coil is fed audio voltage, the cone moves in/out of a magnetic field and produces sound. The passive coil, (One not connected to amplifier) will also move in/out of the magnetic field and "produce" a voltage of its own. The RDO method is used to cancel out this passive coil energy. (Resistive Dampening)
Adire Audio had mentioned this on their site as a method to use when only using one coil on a DVC woofer. Unfortunately, Adire is now defunked and that info is no longer available off their web site. I don't recall the specifics of their methodology, but it seems to me, they recommended a common variable resistor, (Potentiometer) between 10K - 47Kohms to dampen the passive coil energy and can actually adjust the "Qts" characteristics of the woofer, (Tuning or calibration) to a desired affect.
That's the best I can offer you on this subject.
Swez
http://www.jbl.com/car/products/product_detail.aspx?prod=P1022&Language=ENG&Country=US&Region=USA&cat=SUB&ser=POS
heres the specs on the amp.
http://www.alpine-usa.com/US-en/products/product.php?model=MRP-M450&lang=en&tab=F
Replies (3)
swez on 09/30/2007 16:24:11
Nice score trunk! Glad you asked before taking the plunge and frying the sub.
RDO is a possible option here. This is when one uses a variable resistor across the unused coil set. It has to be "tuned" as there is always an electrical voltage passing through the passive coil. (Reverse EMF) The variable resistor absorbs "R-EMF" and can be used to tune the "Q" of a sub when a variable resistor is used. (Low power resistor is OK here too)
The sub is rated at 200 Wrms/coil. If you run one coil here, you will risk frying the coil if pushed much above 250 continous watts RMS. To be on the safe side, I would recommend wiring this sub at 4 ohms.
This sub is very efficient in a ported box and the high sensitivity will still give you solid bass. The SPL difference at 220 vs 400 watts is only 3dB less and absolutely safe for the sub and amp.
Swez
trunkisloud on 09/30/2007 17:31:29
word...makes sense to me ...except what is rdo....and emf...whats the meaning behind this madness./?? and so the only reason that it would hurt the sub is the power rating on the coil?
swez on 10/1/2007 10:04:13
EMF is short for Electro-Magnetic Force. In a nutshell, whenever we have a coil of wire in close proximity to a magnetic field, electrical energy is created. (Voltage and a limited amount of Current too)
In this case, the sub has 2 coils. If one coil is fed audio voltage, the cone moves in/out of a magnetic field and produces sound. The passive coil, (One not connected to amplifier) will also move in/out of the magnetic field and "produce" a voltage of its own. The RDO method is used to cancel out this passive coil energy. (Resistive Dampening)
Adire Audio had mentioned this on their site as a method to use when only using one coil on a DVC woofer. Unfortunately, Adire is now defunked and that info is no longer available off their web site. I don't recall the specifics of their methodology, but it seems to me, they recommended a common variable resistor, (Potentiometer) between 10K - 47Kohms to dampen the passive coil energy and can actually adjust the "Qts" characteristics of the woofer, (Tuning or calibration) to a desired affect.
That's the best I can offer you on this subject.
Swez
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