[Ali-E90]

Hi, quick question about using high vs. low quality amps to power a sub.

I know that a sub and amp should be matched as closely as possible by looking at RMS Wattage the amp gives, and the sub can handle.

However, I also know that good quality amps are more efficient at producing louder volumes than low-end amps, despite having the same wattage rating (a JL amp rated at 500W will pound much more than a Thump amp 500W).

If I have a 500W sub, which will be well suited for a 500W JL amp, will it handle 700W from Thump (theoretically) to obtain similar volumes, given that the Thump is less efficient at creating volume from Watts?

Hope my question is clear. Thanks for the help!

[bmw325i]

500watts rms is the same regardless of what amp it is. There are differences between different quality amps like efficiency and dampening factor.

The problem is quite a few low quality audio companies overrate their equipment and usually list max wattage which is usually some made up number that the amp will never produce.

Your sub can handle any size of amp as long as your gains are set properly.

[Ali-E90]

What if the low-Q amp is rated at 500w RMS, just like the high-Q amp? Even though both ratings are the same (RMS), the high-Q will still produce higher volumes (likely from efficiency and dampening factors you mentioned).

If this is the case, does that mean a 600W RMS low-Q amp can damage a sub (at peak volume), even though it produces less volume than a 500W RMS high-Q amp?

[bmw325i]

Originally Posted by Ali-323i

What if the low-Q amp is rated at 500w RMS, just like the high-Q amp? Even though both ratings are the same (RMS), the high-Q will still produce higher volumes (likely from efficiency and dampening factors you mentioned).

If this is the case, does that mean a 600W RMS low-Q amp can damage a sub (at peak volume), even though it produces less volume than a 500W RMS high-Q amp?

No 500 watts rms is the same regardless of the brand and will be the same volume. As long as the amp is truly 500 watts. Usually higher quality amps will come with a birthsheet that shows exactly how much power it can cleanly produce.

You can power any subwoofer with any amp as long as the impedance isn't too low and your gains are set properly.

[Ali-E90]

Thanks, very helpful!

[ctuna]

It doesn't mean they will sound the same.
Power is only a one dimensional measurement.
There are bunch of other specs like distortion at a particular frequency.
slew rates and other stuff.

[bmw325i]

Originally Posted by ctuna

It doesn't mean they will sound the same.
Power is only a one dimensional measurement.
There are bunch of other specs like distortion at a particular frequency.
slew rates and other stuff.

Sure the sound quality might not be the same. RMS ratings are usually measured at a certain amount of distortion, especially if the amp is cea 2006 compliant. Usually if a company isn't cea 2006 compliant you usually shouldn't trust their ratings anyways. The frequency it is measured at does make a difference since amps don't put out as much power at lower frequencies. If an amp isn't cea 2006 compliant there is just no way to know how they got the number they got.

[makkan00]

One example is
Alpine PDX 1.1000 = produced hardly 1000W. Max clip free was approx 950W.
Jl Xd 1000/1 = produced around 1250W clip free sound.

My 12W7 worked way better with JL Xd 1000/1 than alpine PDX.1.1000.

[ctuna]

Marketing always trys to make the specs look better.
That's why they always quote peak power and no distortion specs
in mass marketed crap.
There are a few good company's that are actually conservative about there specs better to stick with them if you want a quality trouble free product.

[mathematics]

not likely that you'd ever push your amp at max RMS wattage anyway. just buy the highest quality amp you can afford. you will have it for a long time and it will give you years of enjoyment and have a higher re-sale value.

[bmw325i]

Originally Posted by makkan00

One example is
Alpine PDX 1.1000 = produced hardly 1000W. Max clip free was approx 950W.
Jl Xd 1000/1 = produced around 1250W clip free sound.

My 12W7 worked way better with JL Xd 1000/1 than alpine PDX.1.1000.

That pdx should have produced over 1000 watts. They are always a little over what they are rated and even come with a birthsheet. I had a pdx m12 that did like 1350rms.

Rockford Fosgate really underrates their amps. A 1500 watt amp will produce close to or over 2000 watts. A 2500 will do 3000 easily.

[mathematics]

provided the electrical system can actually handle it. you're not going to see 2000 watts. that would be full output of a 140amp alternator at 13.8V. you'd be lucky to be close to that at 7,000 rpm. people need to stop harping over wattage and focus on the install. hell, proper sound deadening can give you the equivalent to adding more powerful amps just by silencing noise.

Originally Posted by bmw325i

That pdx should have produced over 1000 watts. They are always a little over what they are rated and even come with a birthsheet. I had a pdx m12 that did like 1350rms.

Rockford Fosgate really underrates their amps. A 1500 watt amp will produce close to or over 2000 watts. A 2500 will do 3000 easily.

[bmw325i]

Originally Posted by mathematics

provided the electrical system can actually handle it. you're not going to see 2000 watts. that would be full output of a 140amp alternator at 13.8V. you'd be lucky to be close to that at 7,000 rpm. people need to stop harping over wattage and focus on the install. hell, proper sound deadening can give you the equivalent to adding more powerful amps just by silencing noise.

It could be done, I wasn't really talking about the e90 specifically though just amp ratings.

The stock alt is 185 amps who knows what rpm's it produces that at though. Music is very dynamic and with enough batteries they'll be able to handle the peaks in the music and recharge on the not so bass heavy parts of the song. I'm using close to 3kw on the stock electrical with just an xs power battery. Although I could use at least 1 more battery just to be safe. It sucks that nobody makes a high output alternator for our cars. I've been looking for one of those since I got the car.

[mathematics]

i agree, with A LOT OF WORK, it could be done lol, but most people just wanna throw thousands of watts in and think they'll actually achieve rated output with a stock electrical system. =) plus, you won't see 185 amps at 13.8V until you're high revving. you won't be cruising at 2k rpm and getting extreme output.

Originally Posted by bmw325i

It could be done, I wasn't really talking about the e90 specifically though just amp ratings.

The stock alt is 185 amps who knows what rpm's it produces that at though. Music is very dynamic and with enough batteries they'll be able to handle the peaks in the music and recharge on the not so bass heavy parts of the song. I'm using close to 3kw on the stock electrical with just an xs power battery. Although I could use at least 1 more battery just to be safe. It sucks that nobody makes a high output alternator for our cars. I've been looking for one of those since I got the car.

[Ali-E90]

Thanks for all the info... personally, I was just asking hypothetically. I already have 2 Fostgate Punch amps installed in the car, but they're both 2 channels and I need to add more channels to the car. I have a handful of idle amps from cars passed, and was just trying to figure out what might work best.

In the end, I think my setup will look like this:
Sony 4x75 - front doors and rear deck
Punch 2x100 - underseat
Punch 2x150 - bridged to mono sub enclosure in trunk

I have other amps as well as access to some quality, but really old amps (HiFonics Zues and Jupiter amps), but I think I'll stick with the newer stuff... probably a bit more efficient on power consumption.

[mathematics]

Sounds good