help with rms vs peak watts

[luckyj86047 10+ year member]

if i have 3 subs in a ported box does that mean they require less power then in a sealed box?and if i put too much power too them in a ported box won't that make them distort?

Click to read more...

 

[USAFbro 10+ year member]

nope. as long as the amp is putting out "clean" power, you will be just fine. and dont look at peak ratings, theyre BS, just focus on RMS

what is the box tuned to?

 

[Phoenix Risen 10+ year member]

a lot of the answer to your question depends on the specs of the box and the subs. we need more info.

 

[luckyj86047 10+ year member]

well they are cheap subs 3-pioneer 303 12 inch subs and the box is 1.60 cubic feet per chanmber

 

[Imtjnotu 5,000+ posts]

How muc power do u have on each?

 

[THATpurpleKUSH 5,000+ posts]

Just give them the rms power they are rated for and you will be fine. Peak or max power is all a marketing trick to get you to buy their product.

 

[luckyj86047 10+ year member]

i have 410 watts going to each one

also should i face the slot ports toward the front of my my truck or should they be faced up toward the roof of the truck?

 

[THATpurpleKUSH 5,000+ posts]

It appears they are rated for 250rms so I wouldn't go over that.

 

[luckyj86047 10+ year member]

should the ports be facint up toward roof of truck or forward toward front of vehicle

 

[zako 10+ year member]

There is ABSOLUTELY no reason to match subwoofers RMS wattage with amplifier power exactly. Sometimes, you can run a 600watt RMS subwoofer off a 250watt amplifier with no problems. In other cases, you should have those 600watts available in full.

One good rule of thumb is to give your subwoofer just enough RMS wattage so that at this wattage in the given box configuration, the subwoofer reaches its xmax limit at say 30Hz. If this wattage is higher than subwoofer's own RMS rating, then take the lower number. The logic behind this is that there is no point to provide more continuous power than what's allowed by essentially mechanical xmax limit. Of course, the cone usually can excurt way beyond its xmax, but in that region it's non-linear, and we basically don't know what's going to happen, specially in SQ area. One way to answer this question is to download the latest WinISD alpha. Load into it the T/S parameters of the woofer, switch to excursion plot, and keep adding wattage until the excursion exceeds drives xmax limit at say 30Hz.

You can ignore this rule of thumb if you can also predict from the modeling software that you can reach the necessary SPL with a much lower RMS wattage than what's necessary to reach a subwoofer's xmax limit. Example: I know very well that my 300wrms RE Audio SRX12 subwoofer will play louder than necessary in my car while running off my 250wrms amplifier. So I can use this subwoofer as a yardstick in the modeling software. To reach 103dB SPL at 50Hz, this sub needs 90watts according to WinISD. Loading into WinISD (in their respective sealed box configurarions) subwoofers RE Audio SE/X12, Infinity Kappa12 120.9w (2ohm), and Image Dynamics IDQ12 (dual 4 ohm), shows that each one of these subwoofers will reach exactly the same SPL with 90watts or less power. Based on this analysis, I can conclude that I can run all of these three subwoofers off a 250watt rms amplifier, even though they're rated for 600watt, 350watts, and 700watts RMS respectively. To make a second illustration, I load into WinISD Dayton Reference HO12 (DVC) and Alpine Type-X12. To reach the SPL of 103dB at 50Hz, both of these need over 200watts. Based on this analysis (ignoring xmax for the monent), it is clear to me that to run these subwoofers I probably need at least 250watts time 3 = approximately 700-800watt amplifier.

 

[THATpurpleKUSH 5,000+ posts]

I was saying just to run recommended rms, because its an entry level pioneer, pretty sure its a 1.5in coil with kapton former, so its not gonna handle much at all.

 

[shizzzon 10+ year member]

if you use winISD for car audio only then you will never learn more than what you might know now...

WinISD cannot predict car audio environment, NO software can!

Only L.E.A.P. can. I own it but requires a massive amount of measuring tools to calculate the entire vehicle's acoustic properties.

Here is a real interesting fact to take into account-

If one graph in WinISD is off, it will effect most to all others!

WinISD CANNOT accurately calculate the impedance curve of a model in a car.

I have personally compared more than once to prove to others to stop relying on speculation..

WinISD is not to be used for car audio performance speculation!

When my impedance curve is different than what winISD says it will be, guess what happens?

The xmax, xmech(winisd doesnt have a graph for this) and power consumption are ALL wrong.

The only real reason to use winisd is to calculate port length.. that's it.

WinISD is no where near as advanced as L.E.A.P. is therefore cannot be used as such.

 

[zako 10+ year member]

if you use winISD for car audio only then you will never learn more than what you might know now...
WinISD cannot predict car audio environment, NO software can!

Only L.E.A.P. can. I own it but requires a massive amount of measuring tools to calculate the entire vehicle's acoustic properties.

Here is a real interesting fact to take into account-

If one graph in WinISD is off, it will effect most to all others!

WinISD CANNOT accurately calculate the impedance curve of a model in a car.

I have personally compared more than once to prove to others to stop relying on speculation..

WinISD is not to be used for car audio performance speculation!

When my impedance curve is different than what winISD says it will be, guess what happens?

The xmax, xmech(winisd doesnt have a graph for this) and power consumption are ALL wrong.

The only real reason to use winisd is to calculate port length.. that's it.

WinISD is no where near as advanced as L.E.A.P. is therefore cannot be used as such.

My arguments still stand. I do not propose using WinISD or other box modeling software to model in-car audio frequency response. I am telling you that it's pointless to run an amplifier more powerful than what your subwoofer allows mechanically. This is something that box software can help you to calculate. The answer to this question does not seem to depent on in-car frequency response. I also propose using WinISD to calibrate the size of amplifier to a subwoofer based on in-car response of a subwoofer that you HAVE ALREADY USED with success, based on what your ears tell you, in your car. Read carefully.

 

[OldSchoolRF 10+ year member]

Just run the subs at their rated rms and you'll be fine.