Are watts cumulative?

[SicAudio 5,000+ posts]

yeah i have read the same thing, but it does say quality as well. some but not near enough of the decks out there boast Hi-volt preouts and are just marketing.. my 690UB deck has true 4 volt outs and so does my older Alpine but they are few and far between so you would be correct saying that it truly doesn't matter these days.

cookie cutter products and marketing have made this become a misconception when it really used to be a truth..

 

[SicAudio 5,000+ posts]

i use the 25% rule..

meaning I go up 25% on an amps power over the speaker/subs needs..

 

[Lowrdr 10+ year member]

I will, thanks for the link!

 

[whitedragon551 5,000+ posts]

yeah i have read the same thing, but it does say quality as well. some but not near enough of the decks out there boast Hi-volt preouts and are just marketing.. my 690UB deck has true 4 volt outs and so does my older Alpine but they are few and far between so you would be correct saying that it truly doesn't matter these days.
cookie cutter products and marketing have made this become a misconception when it really used to be a truth..

Agreed. Like my previous link states some HU's start clipping before you reach the highest volumn and thats where you see your preout voltage at its highest rating. My 9887 is different. O Scope testing shows you can turn it all the way up to 30/30 and the preout voltage NEVER sends a clipped a signal through the RCAs. Somehow Alpine limits it internally. I havent seen any testing show clipping on the speaker outputs through the internal HU amp.

i use the 25% rule..
meaning I go up 25% on an amps power over the speaker/subs needs..

Im a fan of overhead. However Im going to leave that out of here until the OP can read up.

 

[daboyfrumdabx 10+ year member]

Underpowering a speaker doesnt damage a speaker EVER. Clipping damages speakers.
Clipping (audio) - Wikipedia, the free encyclopedia

I would also strongly suggest you read through this site:

Basic Car Audio Electronics

Section 29 is the section about underpowering and clipping.

That^ Think about it this way. If underpowering speakers could kill them, you'd need an amp any time you wanted to run aftermarket speakers as more often than not, they will be underpowered off HU power. Read those links and you will be well on your way to putting together a proper system and making it last.

 

[Lowrdr 10+ year member]

Oh, and I surmised that strapping means something like daisy-chaining the amps, yes?

 

[SicAudio 5,000+ posts]

yes daisy chaining //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

and very good points WD //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[Lowrdr 10+ year member]

You must lose more newbs with that link, why come back. Seriously what a wealth of information, it is obvious the author is passionate about his craft. I spent most of last night reading through it, much to my wife's chagrin.

Parts I had to read a couple time but I feel I have a firm grasp on clipping, what it is, how it happens, how the amp plays into it and the potential fallout from it. One question on clipping I didn't see specifically addressed is how do you know when it is happening w/o a scope? Trained ear? What would you listen for to know if your signal is being clipped?

So now I understand about under powering, but what about overpowering your speakers. Is it as simple as don't turn the volume past the capacity of the speakers? And if so how do you know you are approaching that threshold?

Thanks again for that link I know I will reference it often in my install. I particularly like the parts on fuses/wire gauge and amplifiers. Still lots more to discover.

I'm Chester BTW, from Boston. Thanks again.

 

[whitedragon551 5,000+ posts]

You must lose more newbs with that link, why come back. Seriously what a wealth of information, it is obvious the author is passionate about his craft. I spent most of last night reading through it, much to my wife's chagrin.
Parts I had to read a couple time but I feel I have a firm grasp on clipping, what it is, how it happens, how the amp plays into it and the potential fallout from it. One question on clipping I didn't see specifically addressed is how do you know when it is happening w/o a scope? Trained ear? What would you listen for to know if your signal is being clipped?

So now I understand about under powering, but what about overpowering your speakers. Is it as simple as don't turn the volume past the capacity of the speakers? And if so how do you know you are approaching that threshold?

Thanks again for that link I know I will reference it often in my install. I particularly like the parts on fuses/wire gauge and amplifiers. Still lots more to discover.

I'm Chester BTW, from Boston. Thanks again.

Sometimes you can hear clipping, some times you cant. You can use the DMM method which reduces your chances of clipping, but its not 100% as nobody knows all the points where every amp starts sending a clipped signal. Heres a tutorial on that:

How To: Set your Amplifier Gain - SSA Car Audio Forum

And again depends on the speakers. Some can take more than rated, some cant, all depends on the quality of the equipment and the install. There is a way to tune your amp with the DMM method so you can put rated power to the speakers. For example lets say you have an amp that does a true 75wrms per channel, 4 channels, and your going to run all 4 speakers on their own channel. The speakers are rated at 50wrms per speaker. When doing the math just substitute the speaker rms rather than the amps rms power.

Examples amp rms

Voltage = sqrt(75W X 4 ohms)Voltage = sqrt(300W*ohms)

Voltage = 17.32V

Speaker rms

Voltage = sqrt(50W X 4 ohms)Voltage = sqrt(200W*ohms)

Voltage = 14.14V

I mentioned earlier in the thread. Headroom:

Amplifier Headroom - SSA Car Audio Forum

 

[daboyfrumdabx 10+ year member]

You can sometimes notice clipping by ear, it will translate to audible distortion. So basically when the sub starts sounding like ish, you're likely clipping. Some amps and bass knobs actually have a clipping indicator on them in the form of an LED that will light up/change color to indicate clipping is happening.

Most subs can take fairly more power than they're rated for, as long as the signal is clean. If you're not getting any distortion, or stinky smells, the sub is likely taking the excess power like a champ. However, it's not necessary to worry about it taking excess power. Just don't turn the gain up too high, this way you can still put the volume up and not worry about overworking your subs/speakers.

Biggest indicators that you have a problem will be audible distortion, burning smells, and amplifier cutting out. If any of that happens, you either have the gain set too high, too low of an impedance presented to the amp, or faulty wiring.

 

[Lowrdr 10+ year member]

Thanks for the previous responses, I understand. The indicator light seems like a cool function.

Any comments on my second query:

"So now I understand about under powering, but what about overpowering your speakers. Is it as simple as don't turn the volume past the capacity of the speakers? And if so how do you know you are approaching that threshold?"

I understand about tuning the amp as proffered above but barring doing anything like that if your amp is higher powered than your speakers (the 25% + rule mentioned) how do you ensure you do not damage the speakers? Is the answer simply not to turn it up too loud?