Question about RMS & ohm load safety

[nomorspam]

Hi,

I have a Rockford Fosgate P1000-1bd which is 1-ohm stable @ 1000w, 2-ohm @ 500w, 4-ohm @ 250w.

The sub is currently running 2 KFCW3011 SVC 4ohm wired for (I believe) 2ohm load, so the amp RMS (500) is below the 2 subs' RMS (~800).

My question is regarding what I should do since I'm downsizing from 2 subs to 1 sub to regain trunkspace. I was looking at the Rockford Fosgate P3D2-12 or P3D4-12 -- the only difference between them being that they're 2ohm or 4ohm (both DVC). Should I go with the P3D4-12 and wire for 2ohm load, effectively making it the same as my current setup? Or should I go with the P3D2-12 and wire for 1ohm load?

My greatest concern with going with 2ohm @ 1ohm load is that the RMS of the amp will fry the coil of the sub since it's only 600w RMS/1200 peak (if I turn it up too much). Am I going to lose a ton of power by running the 4ohm sub @ 2ohm load @ 500w?

Thanks for your help in advance.

I am also open to recommendations for this wattage if you have them. I can't change the amp, but I can change the sub I buy. Willing to go to 10" for even more trunk space if anyone thinks I can get the same oomf and accuracy as I do currently. I run a sealed box, and plan to do the same with the sub I buy next.

Click to read more...

 

[LosIsATool 5,000+ posts]

budget? much better woofers out there than fosgate

 

[nomorspam]

Trying to keep it under $200 for the sub and grill. I did some more looking and saw alpine type r is ~1000w RMS and I could run the SWR-12D2 @ 1ohm load... I am more looking for quality and not as much warning people that I'm entering the neighborhood...

 

[LosIsATool 5,000+ posts]

VVX-10 V2 D4 - Skar Audio 10" Dual 4-Ohm VVX Series Subwoofer

They have a dual 2 also. That's the one you need

 

[nomorspam]

So you think it'll be plenty of power to wire this up at 2ohm load? I only get ~500w rms from the amp that way--just want to make sure I'll have enough power.

 

[LosIsATool 5,000+ posts]

So you think it'll be plenty of power to wire this up at 2ohm load? I only get ~500w rms from the amp that way--just want to make sure I'll have enough power.

Get the dual 2 and wire at 1

 

[nomorspam]

Get the dual 2 and wire at 1

That's where I'm concerned-- I'll be pumping 1000w or so RMS at the sub then... and that's 600w RMS... I'm just nervous.

 

[LosIsATool 5,000+ posts]

That's where I'm concerned-- I'll be pumping 1000w or so RMS at the sub then... and that's 600w RMS... I'm just nervous.

It will be fine. Amps only give full power for split seconds. You can also control the gain to send less power but that's not needed here

 

[Massive spl]

Do not buy skarabge junk. I'd run Rockford before skar

 

[nomorspam]

OK, Perhaps I should revise my needs then...

Primary: longevity. I don't plan on upgrading after this, I want it to last.

Secondary (but close to primary): Sound quality

Tertiary: price

I'd like to keep the box, sub, and grill (if available) under $250. I'd rather sacrifice some SQ before spending $500 on a sub or something...

I appreciate the input on subs, but can you explain why Skars are good/bad? vs RF or Alpine type-r? etc

Thanks!

 

[LosIsATool 5,000+ posts]

Do not buy skarabge junk. I'd run Rockford before skar

Lol they are built right beside your favorite.

Op a few years ago the owner of Skar did some dumb stuff. The gear has always been good.

His company was actually helped from the start by the man most in this hobby want to have butt$ex with.

There is absolutely nothing good about a RF woofer. They are more plastic than motor.

 

[Jeffdachef 5,000+ posts]

That's where I'm concerned-- I'll be pumping 1000w or so RMS at the sub then... and that's 600w RMS... I'm just nervous.

look up box rise or impedance rise. Youll never see 1000 watts out of a 1000 watt amp.

 

[MrFoca]

You would be fine running over RMS. Most good subs are sandbagged. But like Jeff said, after box rise it won't be sitting at 1 ohm. So you will see less than rated.

 

[nomorspam]

look up box rise or impedance rise. Youll never see 1000 watts out of a 1000 watt amp.

From what I understand the P1000-1bd is under-rated in terms of RMS; however, thanks for the info. What would you suggest for my setup? I'm now leaning towards the Alpine SWR-12D2 wired for 1ohm load (so ~1000w rms) due to price/ease of use. Remember I'm using the kenwood KFC-w3011's right now and I think they sound decent... so I guess I've got a lot of room for improvement?

 

[Jeffdachef 5,000+ posts]

From what I understand the P1000-1bd is under-rated in terms of RMS; however, thanks for the info. What would you suggest for my setup? I'm now leaning towards the Alpine SWR-12D2 wired for 1ohm load (so ~1000w rms) due to price/ease of use. Remember I'm using the kenwood KFC-w3011's right now and I think they sound decent... so I guess I've got a lot of room for improvement?

Its not rms or true power or anything related to that, its just physics. your sub will never see a true 1 ohm load when wired to 1 ohm, you'll be around 1.5 to 2.5 ohms depending on enclosure, hence thats why you'll never see full 1 ohm power out of any amp unless you wire to .5 ohms or overdrive the amp into clipping and distortion. Voltages also have an impact on amplifier power so if you are not at 14.4 volts, you wont see rated power either. When I say read up on it, doesnt mean you pass it off and stick to your own logic.