Subwoofer help

[jaylah]

Hey guys,
I've just purchased a RF 15" P3 sub (http://www.rockfordfosgate.com/products/product_details.asp?item_id=91829&locale=en_US) and i was wondering is it possible to wire it so it's in a 2ohm load? According to the "wiring wizard" on the link, i can only have 4ohm and 1ohm. Sorry i'm new to this stuff
Thanks! :)

[arverson]

yup only 4/1ohm

why do you wanna run it at 2? your amp makes more power at 2? if so, see if you can swap the sub for a dvc 4ohm one, or svc 02ohm if they have it.

what amp/s do you have?

but really whatever amp you have, you'd probably be happy enough with the juice provided at 4ohm

[jaylah]

oh that sucks :(
i don't have an amp for it, i've been researching and ~500wrms @ 4ohm is usually more expensive then ~500wrms @ 2ohm so i was seeing if the sub could go into a 2ohm load. Also it's hard finding ~500wrms @ 1ohm stable amps :(
i bought the sub off somebody, so i can't swap for the DVC 4ohm :P

[2MPRS]

my amp runs at 820watt rms at 1ohm i got it for 280 from autobarn http://www.optionaudio.com.au/amplifiers_oax801.php

[jaylah]

my amp runs at 820watt rms at 1ohm i got it for 280 from autobarn http://www.optionaudio.com.au/amplifiers_oax801.php

i've never heard of Option Audio, is it any good? and would all Autobarn retail stores sell it?

[2MPRS]

i got mine from autobarn for 280 on special they are a bit of a rip there pretty sure one of the traders sell it here for 290ish

[cc1206]

Jaylah - Option Audio is a reliable but budget brand. In future you should always test out the audio equipment you like first. For example, head over to a car audio (ICE) specialist and have a listen to each subwoofer you're interested in. Heck, ask for some opinions while you're at it as most car audio specialists want you to buy the gear that is right for you, not what gets them the most money.

In any case, you have already purchased the RF sub. From the link you have given, the sub is rated at 500wrms (1000watts peak) with dual 2ohm coils. NEVER look at the peak rating, it will be useless as it's more of a marketing gimmick than anything. What you want is the RMS rating. This is what you require as you will be needing an amp to power that rating.

As mentioned before, you have dual 2 ohm coils. This is the impedance of the sub, dual just means you have 2 sets of coils (ie. 2 sets of positive and negative terminals). To wire these to an amp, you have 2 choices as follows:

1. Wire in series (positive -> positive -> positive of amp, negative -> negative -> negative of amp). This will show a load of 4ohms to the amp.

2. Wire in parallel (Negative -> positive -> positive of amp, positive to negative -> negative of amp). This will show a load of 1ohm to the amp.

There is a diagram somewhere on the net, lemme see if i can find it*

It is important for you to know that each wiring configuration is different. Some amps do NOT "support" a 1ohm load. Hence the reason you will be using a 4ohm load.

The main difference in these loads is the damping factor. The higher the impedance (higher the number) means a better damping factor. Dampin factor : Time for the sub to excurse (brain block hahaha) back in time for the next subfrequency beat. Usually lower loads than 2ohms are for people who want to achieve high SPL db scores. Don't think you need to know that yet :P

Anyway, set a budget for your amp, and then have a look around. Remember you also need a wiring kit (ground + power cables, RCA for signal from headunit -> amp, that wire that tells the amp to turn on but i forgot what it's called cause it's 3am....). Set aside a budget for that too. Also a box for your sub :D

Have a look at MEA (mobile electronics australia): http://www.mobileelectronics.com.au/forums/index.php?showforum=41
They have some good sales, just research it before you buy it :)

Hope i've helped somehow

[jaylah]

Jaylah - Option Audio is a reliable but budget brand. In future you should always test out the audio equipment you like first. For example, head over to a car audio (ICE) specialist and have a listen to each subwoofer you're interested in. Heck, ask for some opinions while you're at it as most car audio specialists want you to buy the gear that is right for you, not what gets them the most money.

In any case, you have already purchased the RF sub. From the link you have given, the sub is rated at 500wrms (1000watts peak) with dual 2ohm coils. NEVER look at the peak rating, it will be useless as it's more of a marketing gimmick than anything. What you want is the RMS rating. This is what you require as you will be needing an amp to power that rating.

As mentioned before, you have dual 2 ohm coils. This is the impedance of the sub, dual just means you have 2 sets of coils (ie. 2 sets of positive and negative terminals). To wire these to an amp, you have 2 choices as follows:

1. Wire in series (positive -> positive -> positive of amp, negative -> negative -> negative of amp). This will show a load of 4ohms to the amp.

2. Wire in parallel (Negative -> positive -> positive of amp, positive to negative -> negative of amp). This will show a load of 1ohm to the amp.

There is a diagram somewhere on the net, lemme see if i can find it*

It is important for you to know that each wiring configuration is different. Some amps do NOT "support" a 1ohm load. Hence the reason you will be using a 4ohm load.

The main difference in these loads is the damping factor. The higher the impedance (higher the number) means a better damping factor. Dampin factor : Time for the sub to excurse (brain block hahaha) back in time for the next subfrequency beat. Usually lower loads than 2ohms are for people who want to achieve high SPL db scores. Don't think you need to know that yet :P

Anyway, set a budget for your amp, and then have a look around. Remember you also need a wiring kit (ground + power cables, RCA for signal from headunit -> amp, that wire that tells the amp to turn on but i forgot what it's called cause it's 3am....). Set aside a budget for that too. Also a box for your sub :D

Have a look at MEA (mobile electronics australia): http://www.mobileelectronics.com.au/forums/index.php?showforum=41
They have some good sales, just research it before you buy it :)

Hope i've helped somehow

wow, almost wrote an essay :P
explained things very detailed and well, i know have a better grasp on what to buy/do
cheers!

[cc1206]

no worries :)

[Joe Bellissimo]

The Option Audio gear is definitely good value for money. Most of my customers buy the higher quality European stuff from me but when someone comes to me on a budget the Option Audio gear definitely performs very well for the money.

This would be the most appropriate model for you IMO: http://www.shoppingsecure.com.au/index.php?_a=viewProd&productId=35

[2MPRS]

agreed i got that runs my 2 12inch subs nicely :)

[amurray]

im not sure about the 800 w amp but if u wanted to run it at 2 ohm and had your hart set on it you could run 1 channel to each of the coils. but i cant remember if its internaly bridged i know you can do that with there bigger amps

also the 800w rms is true it makes 800rms at 1 ohm. but on full gane to maek the 800wrms u will have clipped signal u only really need 500w so turn the gain down to half and no clipped signal = no cooking woofer and finding big flat spots in your music

also when i comes to a box u can not go past the DD audio designed boxes. mostly there boxes are made for subs that move hi volumes of air, so with a sub that size maybe use the box for 1 size smaller like the 12" box for your 15 ", i find these boxes are awesome. i did a 151 db with a single 12 in the dd design box off a Atomic 5000.1

http://www.ddaudio.com/BoxDesigns/highEfficiency/fullSize.htm

try the 12 inch box with the hole in the top so you can fit the sub.

i have this in my car atm its VERY loud and sounds good there tuned to roughly 35hz so can hit some good lows

hope that helps

remember the box is EVERYTHING