Few ohm Q's

[Photonfanatic 10+ year member]

1. How exactly do you figure out how much wattage you will be pulling, at a certain ohm load? For example, my amp is 1200 watts RMS. I want to wire my dual 4 ohm sub for 2 ohms. The sub is rated at 400 watts RMS so I don't want to go too much over that. How much power would I be sending to the sub, at 4 ohms? What about at 2 ohms? Or hell, even 1 ohm? (just curious on that last one)

2. Can someone tell me if the Sundown Audio SA-8 can really take the beating that they say it can? Its rated at 400 watts RMS but there are some people out there saying they're running it at 1000 watts RMS and its doing just fine. Does that seem strange to any of you? Why would Sundown Audio say that the sub can take less than half than it really can? What do they stand to gain by that? I'm trying to figure out the best way possible to wire this thing up.

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[neo_styles 10+ year member]

Use ohms law. Square root of power times impedance will get you the voltage you need. Move the equation around to solve for other factors.

As for the Sundowns, they can take 1K no problem. Jacob just rates his equipment very conservatively.

 

[Photonfanatic 10+ year member]

Ok so you'd say I'm fine running that little SA-8 V1 (that particular sub) at 1000 watts? And if so, why? Why would a company say that their sub can take less than half? Doesn't make sens to me. You're going to get average Joes that say "Hmm, a 400 watt sub. Better run it at 400 watts so I don't blow it!" And then do just that. Run it at a mere 400 watts. Leaving 600 watts (in the case of the SA-8) on the table. Isn't that 600 watts of BOOM that the customer is going to be missing out on? Wouldn't a company want their customers to make use of every bit of their products capabilities?

That way, after having the product for some time, the customers don't say "Man, I think I want to run a bigger sub. This one is just too little now. Its not as good as I want it to be anymore". And then switch to a different brand. When instead, they could have been told the proper RMS, and been a lot happier with their purchase because they're getting more out of it.

 

[trumpet 5,000+ posts]

2. Can someone tell me if the Sundown Audio SA-8 can really take the beating that they say it can? Its rated at 400 watts RMS but there are some people out there saying they're running it at 1000 watts RMS and its doing just fine. Does that seem strange to any of you? Why would Sundown Audio say that the sub can take less than half than it really can? What do they stand to gain by that? I'm trying to figure out the best way possible to wire this thing up.

When you simply look at it as "Johnny is running his sub at more than double the RMS power rating, it must be a very underrated sub" that leaves out a whole bunch of variables. Maybe he's running a ported box with a subsonic filter set right at the port tuning frequency. Maybe he listens to acoustic folk music most of the time and the big bass beats only come on to show off.

The manufacturer rates their speakers conservatively so they don't get a flood of warranty claims when it's abuse that's the real problem.

 

[Buck 5,000+ posts]

1. How exactly do you figure out how much wattage you will be pulling, at a certain ohm load? For example, my amp is 1200 watts RMS. I want to wire my dual 4 ohm sub for 2 ohms. The sub is rated at 400 watts RMS so I don't want to go too much over that. How much power would I be sending to the sub, at 4 ohms? What about at 2 ohms? Or hell, even 1 ohm? (just curious on that last one)
2. Can someone tell me if the Sundown Audio SA-8 can really take the beating that they say it can? Its rated at 400 watts RMS but there are some people out there saying they're running it at 1000 watts RMS and its doing just fine. Does that seem strange to any of you? Why would Sundown Audio say that the sub can take less than half than it really can? What do they stand to gain by that? I'm trying to figure out the best way possible to wire this thing up.

1. If your amp is rated at one ohm, then check the rating at 2 ohms. Should be around roughly half of 1 ohm wattage, possibly more.

2. All Sundown products are underrated. They are built to last and take abuse. That woofer will do fine on 400w, perform like it's supposed to. You could maybe run 600w-750 daily. Do not run 1000 watts to that woofer, there is no use in it. If you do, might as well get a woofer that is made for that kind of power. People who run that kind of power know what they are doing and probably have the electrical to give the woofer a clean, pure 1000w, not some heavily distorted/clipped watts.

 

[Photonfanatic 10+ year member]

WoofersEtc.com - PA-1500 - Nakamichi 1 Ch 1200 Watt Power Amplifier

There's the amp itself. I'm not sure I follow you on your comment about what the amp is rated at. Says it has various impedances. Unless my newb ignorance is showing again.

 

[NASTY08IMPALA 5,000+ posts]

Well amp specs says it does 800x1@2ohms which i would say is a lil high ..id say u realistically get 6-700 @2ohms which is fine for that sub

 

---------- Post added at 03:06 PM ---------- Previous post was at 03:05 PM ----------

 

Granted u set the gains properly and dont distort the hell out of it

 

[Photonfanatic 10+ year member]

Wouldn't you set the gains at zero for this application? I have a 4v output head unit. Seems we're running this little sub right up to the edge, so it seems like you just wouldn't need the gains turned up any. Or would you?

 

[NASTY08IMPALA 5,000+ posts]

Gains at 0??? no u want to match the desired 4v output of ur hu to the gain on the amp to get the full powrr anything over this is clipping...gain left at 0 will yield 0 sound

 

[NASTY08IMPALA 5,000+ posts]

Im not sure u understand what gain is....its the input sensitivity on the amp

 

[Photonfanatic 10+ year member]

Yeah I know and the more you turn it up, the more power it sends out to the sub. Correct? If so, and we're running the little SA-8 real close to its safe max, then wouldn't you want a lower gain setting?

 

[NASTY08IMPALA 5,000+ posts]

If u wire at 2 ohms and the amp puts out 6-700 realistically @2ohms ur gona wana give it all tge amp has or close..this doesnt mean crank the gain up ..u wana match the 4v on the hu to 4v on the amp

 

[Photonfanatic 10+ year member]

What's the best way to make sure its perfectly matched? Test tones, or oscilloscope? I have oscilloscope.

 

[NASTY08IMPALA 5,000+ posts]

O scope so u can see when the amp is clipping

 

[hispls 5,000+ posts]

Over complicating the hell out of this one. Gain it up until you are happy with the level of output or you notice signs that the woofer is stressing (smell coils or approaching x-mech). Music is dynamic and everyone has different tastes and application so how much power YOU should run really depends on your needs, application, and level of knowledge.

Sufficed to say, if you don't know what you're doing and/or can't afford a couple re-cones while figuring it out, you shouldn't try to run too much more than rated power into an 8" woofer.