I have a slim mount 10" Rockford Fosgate P3SD410 Dual Voice Coil 4 ohm Sub that I'm using in a custom enclosure built into the rear seat of my Wrangler. It will fire downward, at a slight angle. I think I'm good on the box, but not sure how to wire it the amp I already have. The amp is an older 2 channel Rockford Fosgate 150s. I picked it up cheap from a buddy, but would like to use it unless you guys tell me I really shouldn't. The sticker on the amp says it has 37.5 x 2 watts RMS at 4 ohms, and 75 x 2 watts RMS when run in 2 ohm. RF says the sub can run 300 watts RMS, 600 peak... so it seems I'm underpowered. I do not, however, want something that's super loud and kicks a ton. I'm just looking to round out a system with some more bass. How can I optimize this combination...or can I? Thanks in advance!
Replies (6)
cplkittle on 03/12/2008 23:29:26
You can either wire one coil to each channel or wire the coils parallel at 2 ohms to a single channel.
I would recommend wiring both coils parallel at 2 ohms to a single channel because it is almost impossible to set both channels identically. Either way, you get the same output.
The older Fosgate amps are a little underrated, so you will actually be getting a little more than 75 watts RMS. As long as the gain is properly set and you don't overload the sub with alot of distortion, this is ok to do. Don't get greedy with the gain settings. If all you want is a balanced low end from this sub, I would say that this setup will work ok for you. If you feel you need a little more on down the road, I would go for an amp that is rated the same as the sub.
ttocs on 03/13/2008 02:03:01
that amp will not like a 2 ohm mono load. I would wire one coil per channel as most bass is recorded as a mono signal, and I really don't think that amp will last on a 2 ohm mono load.
How old is this 150?
ttocs on 03/13/2008 02:03:02
that amp will not like a 2 ohm mono load. I would wire one coil per channel as most bass is recorded as a mono signal, and I really don't think that amp will last on a 2 ohm mono load.
How old is this 150?
Raghu on 03/13/2008 08:33:06
Well, I wouldn't recommend underpowering a sub. I am NOT saying "underpowering will harm your sub." From my experience, I have seen better quality in sub when it is powered to around 70% of sub's RMS power handling capacity.
The problem with underpowering are:
*Subsonic effects will not be sugnificant
*Bass won't be deep
*Frequencies below 40Hz, will sound feeble, as they require more power to push the diphragm hard in order to produce "long wavelengths"
In your setup, you are powering it to 50%. You can expect you sub. to give just a fill bass to your music.
rockclimbersh on 03/13/2008 09:21:24
So you're saying that the safest way to run it is just one channel to each voice coil in the sub... but that will underpower the sub significantly. My main concern is, I want to wire the sub inside the box once, and not have to take it apart again once it's all screwed together. Maybe I should just cut bait with this amp and get something else? What are your thoughts? I'm not looking to spend a bunch. Thanks for the replies, folks!
Raghu on 03/13/2008 09:59:56
No... no.. in any case, irrespective of whether single coil or both in parallel, the power handling would remain same. Basically, you have to decide on
"Whether you really want "best" performance out of your sub."?
- or -
"Whether you are not a bass freak, and just a fill bass, is okay for you"?
If you say yes to second statement, you can go ahead with existing amp.
Or else, to get best possible performance, you need a different amp. so that you can sufficiently power your sub.
May be, other experts can add their opinion to mine.
Replies (6)
cplkittle on 03/12/2008 23:29:26
You can either wire one coil to each channel or wire the coils parallel at 2 ohms to a single channel.
I would recommend wiring both coils parallel at 2 ohms to a single channel because it is almost impossible to set both channels identically. Either way, you get the same output.
The older Fosgate amps are a little underrated, so you will actually be getting a little more than 75 watts RMS. As long as the gain is properly set and you don't overload the sub with alot of distortion, this is ok to do. Don't get greedy with the gain settings. If all you want is a balanced low end from this sub, I would say that this setup will work ok for you. If you feel you need a little more on down the road, I would go for an amp that is rated the same as the sub.
ttocs on 03/13/2008 02:03:01
that amp will not like a 2 ohm mono load. I would wire one coil per channel as most bass is recorded as a mono signal, and I really don't think that amp will last on a 2 ohm mono load.
How old is this 150?
ttocs on 03/13/2008 02:03:02
that amp will not like a 2 ohm mono load. I would wire one coil per channel as most bass is recorded as a mono signal, and I really don't think that amp will last on a 2 ohm mono load.
How old is this 150?
Raghu on 03/13/2008 08:33:06
Well, I wouldn't recommend underpowering a sub. I am NOT saying "underpowering will harm your sub." From my experience, I have seen better quality in sub when it is powered to around 70% of sub's RMS power handling capacity.
The problem with underpowering are:
*Subsonic effects will not be sugnificant
*Bass won't be deep
*Frequencies below 40Hz, will sound feeble, as they require more power to push the diphragm hard in order to produce "long wavelengths"
In your setup, you are powering it to 50%. You can expect you sub. to give just a fill bass to your music.
rockclimbersh on 03/13/2008 09:21:24
So you're saying that the safest way to run it is just one channel to each voice coil in the sub... but that will underpower the sub significantly. My main concern is, I want to wire the sub inside the box once, and not have to take it apart again once it's all screwed together. Maybe I should just cut bait with this amp and get something else? What are your thoughts? I'm not looking to spend a bunch. Thanks for the replies, folks!
Raghu on 03/13/2008 09:59:56
No... no.. in any case, irrespective of whether single coil or both in parallel, the power handling would remain same. Basically, you have to decide on
"Whether you really want "best" performance out of your sub."?
- or -
"Whether you are not a bass freak, and just a fill bass, is okay for you"?
If you say yes to second statement, you can go ahead with existing amp.
Or else, to get best possible performance, you need a different amp. so that you can sufficiently power your sub.
May be, other experts can add their opinion to mine.
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