I was at a store talkin to a salesman about amps and he was pushin kicker pretty hard. So i asked him why he thought kicker was better? So he told me to hang on while he went and got one in a box. He opened the box on a 150.2 amp and there was a tag in the box that showed that it was fctory bench tested before it left. It also had the amount of power that it put out at 2ohms and the signature of the tech who tested it. On this particular 150.2 it produced 232 watts on the bench bfore it left. Maybe its normal for all of them i just thought it was intersting. The salesman said that on all kicker amps they rate them lower than what they actualy put out. Just thought that was cool.

Moto

 

Rockford fosgate does that too. I bought a Punch 360 a2 about two years ago and it came with a certificate. On the certificate it said at full power it pushed 552 watts @ 4 ohm. That pretty underrated.

 

There are many amp manufacturers that send a certificate with each amp. You will find that all high quality amps will be rated lower than what they will actually put out.
That helps immensely if your competing in competitions.

 

Most of those measurements are for short periods, called duty cycle in the electronic testing trade.

If the 150.2 is rated for 150 watts RMS, that rating means it is capable of delivering that level of power output for 100% of the time it is operating.

If you were to drive that amp at 232 wattts RMS for an extended period of time, it would overheat and shut itself down. Of course, if you can force air cool it, you can run it above it's 100% DC rating.

That 232 watt measurement was probably done for a very short period of time, something on the order of 5 seconds or so.

Truly high performance amps are rated by their full output power, in watts RMS, at 100% duty cycle.

The secondary rating the sales guy showed you on the Kicker amp would be a different rating on a high dollar amp. It would be listed as the "dynamic headroom" and would be expressed in db's. It is usually accompanied by the duty cycle it can provide that power output for as well.

3 db's of dynamic headroom means an amplifier can output TWICE it's rated RMS power, without significant distortion.

For what it's worth, you would be hard pressed to hear the difference between 150 and 232 watts anyway...

I know it's not truck related, but:

If you want to see some truly impressive amplifier designs, go to a dealer that sells McIntosh home stereo equipment.

For the past 50 years or so, they have built amps that deliver full output power into any load from 1/2 to 32 ohms. Expensive, but designed to last for the lifetime of the owner.

Audition them with some good CD's of music you know. Watch the output power meters of the amp while you play the CD's. I'll bet you will be surprised at just how loud a true 100 watts RMS signal can be.

 

 

Huhtjats good toknow thaks.

 

Quite a few companies are including bench'd power ratings with their amps these days. Its great marketing when someone goes in and buys what they think is a 300w amp, hook it up, and it is louder than their old X brand 300w amp. What they really bought was a 450w amp that is 'mislabeled' as a 300w amp. It is very common practice to grossly underrate amps.

As far as the power # on the bench being false, I will disgree. They are typically rated at 13.8v which can provide a realistic output number. Some amps are bench'd at 14.4v which gives a slightly elevated number than what it would do when hooked up in a vehicle (due to voltage loss in the power wire and from current draw from other accessories). If the heatsink can handle the 'additional' power it will be fine. Besides, they probably miss labeled it.

What I find to be the best salesman inspired rating of an amp is the 'stand on it and jump up and down' rating. More common with subs but you will find some salesmen more than happy to show you that the amp he is selling is jump certified.

 

I haven't been fortunate enough to find manufacturers that are willing to lose a marketing war by under-rating their amps. There is a huge difference between under-rating an amp and designing an amp that has a high level of dynamic headroom...

Again, I haven't been exposed to this practice yet. If anything, I see the trend going the other way. I was recently looking at Kenwood amps, just because I was in Atlanta and they have a Kenwood "outlet" store. Without exception, every single amp had a label that was approximately 20% higher than what the true RMS capability of the amps were.

All of those #'s are meaningless and they have done nothing but ruin the audio market. As I said before, truly good hardware is rated the way the FTC designed many years ago: RMS power, into a known impedance, from 20-20KHZ, at ??% THD, with ??db of dynamic headroom, at a specific voltage. Period. No guessing, loopholes, etc.

Funny, they came up with the spec to eliminate this exact rating problem.

Again, the using of 14.4v for a rating is exactly opposite of the under-rating game. It is a stretch tactic to get the absolute highest output measurement possible from the amp.

Pioneer (I'm sure others do as well) likes to play a little game with their home stereo equipment: They rate the amplifier's output from 40 to 20KHZ instead of the standard 20 to 20KHZ. Know why? A huge portion of an amplifier's load is in the very lowest frequencies it is required to reproduce. Remove the lowest and the amp's apparent power output increases (with respect to distortion). Again, not having an enforceable standard to measure against has done nothing but make audio gear a liar's paradise.

Remember the "400 watt" EQ / Amplifiers you used to get at the flea market years ago? 1 inch tall, 6 inches wide, 5 inches deep. You'd be lucky to 50 watts RMS out of 1 of those, but they could deliver a 400 watt peak for 5 milliseconds into a 16 ohm load at 1KHZ so that made them a 400 watt amp, right?

As a rule I would stay away from any manufacturer who did not list their equipment via acknowledged engineering recognized measurements.

Just my $.02...

 

Great stuff B-man. That's the kind of info the young guys need to hear. Heck, even some of the experienced guys. There is definitely a numbers game being played, and the reason is to gain an upper hand with the consumers, by making a product seem to be something it's not, to some degree. I've worked for 30 years for General Electric and I know the way it is when it comes to deceiving the consumers with BS and fluff.

 

Thanks, 97 -

I get really irritated by all this horse***** everyone is trying to call "marketing". True marketing is both about getting attention and about FACTS, some of which should include how your product works in the REAL world.

The audio world is overly complicated because of all of this. I routinely get asked why I use those big power amps when I could have bought a so-and-so HU that has 50 watts per channel x 4?

As far as marketing goes, the best demonstration I've seen as to a power amps' output current capability was done by no other than Frank McIntosh.

He took a signal generator, set it @ 60HZ, connected it to the input of 1 of their big monoblock amps, and then connected a Hoover upright vacuum cleaner to the amps' speaker terminals. He then turned it all on and vacuumed the store for 10 minutes or so. The amp barely got warm to the touch.

That's true power...

 

Considering McIntosh makes/made some of the highest quality amps ever built, that's not too hard to believe.

With a vacuum like that you're looking at about 10 to 15 amps depending on the model.

My Phoenix Gold amps came with a test certificate tested to 280.71 watts at 14.4 volts.. my truck provides a steady 14.2 volts, I dont expect to get a steady 280 watts out of them but I wouldn't doubt that its at least around the 250 watt range as Phoenix Gold has rated it at.

 

OK I agree with b-man and from past tips and converastions with the man I feel that he really knows his stuff. If he says Some guy vacuumed a store with a car amp I would say that is 100% possible so if that's true then what he says about market fluff is true too. From my recent car audio purchases I would say he is dead on track. It's a nightmare trying to figure out who has a good product anymore when everyone rates the crap different. Then you have everyone from salesman to owners swear up and down that their stuff is better than gold itself. Lot's of times I just wanted to pull out my big BS flag, take the flag off the stick and beat the person with the stick from the flag and then wrap their body in the flag. I'm just an amaturer and can out talk some of these guys on the specs.

If you wanna get into car audio I have come to learn it pays to learn and know your stuff before you blow your cash on fluff...

 

Last time I was at the shop the owner showed me an interesting bit of info. It was a sheet that showed 11, yes 11 different ways that power can be rated! rms, peak, voltage, it was all there. The real bitch of it was that all 11 ways were right!
You could use any method to skew the numbers for your specific application.

How is that for confusing!!!

 

twistedfinn -

Please try to get a copy of that sheet and post it here for us all to see.

Although mathematically it may be possible to make different numbers "work out" for the result you are seeking, reality says that ratings truly work one way.

For example: 1000 watts RMS, the FTC rating method =

89 volts across 8 ohms impedance with 11 amps of current flow.

Period. No guesses. No hype, it is what it is.

Ohm's law states P=IxE, P=I2xR, I=E/R, etc. You CAN skew numbers if you ignore one of the variables, but that does not make it true. For example:

I was in a audio store where a customer was asking why one amplifier was way more expensive than another. The sales guy responded:

Power (P) equals voltage (E) times current (I).

This is true.

He then stated that it is harder to create an amp that delivers high current than it is to make an amp that delivers high voltage. He then stated that one of the amps made lots of voltage (E) and a little current (I); while the expensive amp made lots of current (I) and little voltage (E).

Now, mathematically this can work. 100 volts (E) x 2 amps (I) = 200 watts (P) and 100 amps (I) x 2 volts (E) = 200 watts. So, what's the difference?

The critical missing part of the equation is the load (speaker) usually defined in Ohms (R).

Voltage is the force that causes current flow to occur. The higher the resistance, the more voltage required to make current flow at the same rate. So, if you plug the load into the math, it is not possible to have 2 different amps delivering the same power at different voltage levels.

100 watts, into a "normal" load (8 ohms), will always be 28.5 volts with 3.5 amps of current flow. You cannot have 3.5 volts (E) with 28.5 amps (I) of current flow into an 8 ohm load (R). Won't happen electrically.

For the rating to be accurate, you have to plug the variables into EVERY variation of the equation and have it work. If the numbers won't work in every combination, there are 1 or more of the numbers that is wrong. Math doesn't lie, only people do...

This is why the FTC spec is so important to measuring (and reporting) electronic specs.

Please try to post that sheet. I'm curious as to the contents...

 

Dang b-man what are you a audio expert or a math teacher, jk LOL

ON OTHER NOTES:
I've started on the install. So far I am about 16 hrs in and still have some left to do. I have really taken my time and have ran into a few hitches. All that is left is to ground the amp, run the remote wire, and I have chosen to run new wire into the doors if at all possible, I tried for about 1 hr today but no luck and it got dark on me. I 'm hoping this really rocks and I took a few pics to post later.