Pros and Cons to under powering subs, and other design info

[graham0599]

I had two Kicker 15" L7's on 300rms for a while bc the Audiopipe 3k had crapped out and I had the amp laying around, and I didn't wanna not have any bass while I waited for it to get fixed. I no longer have that system but the amp was just fine

[Krakin]

Increasing resistance isn't what kills amps.

[scooter99]

But if someone is budgeting a system, say they have 8 subs at 1500 "rms" and plan on multiple amps. If they're putting a single 2000 watt amp per sub in their plans but have 4 amps right now that's one per pair. If they plan on adding 4 more later on then the original 4 would play the system just fine right?

I understand what you're saying on running at rated power, I get it. But I'm thinking about the guys who want to run bigger subs, but don't have the budget for full power at first. Not everyone can get subs and amps rated at 50k watts.

So at that point what would the effects be of running say half power or three quarters power. Ive always read that you should plan for overhead in a system. Is a sub rated for 1500 watts going to overtax an amp rated for 1000 watts?

.

What does the bold mean? Are you under the impression subs pull power from amps?

The only con would be less output. How much depends on box design, driver efficiency, and a few other things.

No I wasn't I was just trying to think as someone with little to now knowledge and ask those types of questions.

If an amp is rated for 1000 watts at a certain ohm rating, usually the max is 1ohm, then that's really all you can expect out of that amp. Obviously it's a general area, not 1000 watts and that's it. We've seen numerous tests where a 2,000 watt amp is putting out 2200 watts plus on proper electrical etc. The other exception is the impedance it's wired at, if wired lower to say .7 or .5 ohms. However, I've seen very few companies that will even give a rating for an amp wired lower than the "recommended" lowest ohm load.

No what I was basing that sentence above (bold) was I've also seen people around here saying stuff to the effect of - these subs are power hungry, or they can take so much more, my amps are struggling to keep up with the subs. Stuff like that. I've always wondered on those comments what they mean. Just my inexperience of not having larger set ups, and being able to tell those things. But if I'm questioning that as someone who's been around a while, then what would someone as a newer person to the hobby be asking. I'm just trying to get some things out there. For my own benefit as well as others. You all know how I work by now. I like to be informative.

I see what you mean now. It's absolutely fine to under power a sub until you can afford more power.

It's no different than playing at 1/2 volume (1/2 rated power if rated powers match)

This was actually my thoughts on it. I know that music doesn't hold a certain wattage, i.e. max or min etc, because the demand in the signals are always changing. That makes complete sense. Which is why we do the set up's with the dd-1 setting them to max unclipped volume, and max unclipped gain. Because at max volume and max gain, the highest demanding note in the song should not theoretically go above that clipping point. The other signals are well below that point throughout the song, so there's nothing to worry about. Plus, there aren't many people out there that listen to their music at max volume anyway.

Half rated power at max volume and max gain un clipped is going to be well under what that sub can handle so there wouldn't be any worries about if the sub can handle it or not. It would more likely be, can you turn it up loud enough to get the best potential out of the sub at the half rating? Then the second half of the rating is added later, then it doesn't have to be turned up as loud to get that same performance out of it, but there's so much more ability at max power vs half power. If I understand it correctly.

Thank you.

Buy the subs to handle the power you will eventually run and don't worry about what you are putting to them in the mean time. You won't hurt anything. A sub cannot overtax an amp. Only you can do that.

Buy the subs to handle the power you will eventually run and don't worry about what you are putting to them in the mean time. You won't hurt anything. A sub cannot overtax an amp. Only you can do that.

I agree with what he said. The only way you could really "overtax" an amp would be wiring below rated impedence. Running subs under rated power isn't going to hurt anything except possible loss of volume. Typically higher power subs have stiffer suspensions and more mass, therefore needing more power to reach "full potential". Not going to hurt anything by running half power till you can afford more power.

Thank you everyone for your input.

Oh sorry I thought I quoted you too Krakin. By your comment do you mean like what Triticum said, wiring below rated? A question based off of that for you would be, if you're wiring to .5 ohms vs 1 ohm, but still running at the max unclipped volume and gain, is that still harder on the amp? My guess is yes because even though it's still unclipped, the lower impedance is still harder on the amp, makes it work harder, and thus gets hotter, and has potentials of failures. Is that about right?

If not, could you elaborate a little more?

I'll tell you this much guys, I'm sure you already know where I'm going with all this besides learning. I'm planning my first biggest ever build. I know that in a short amount of time I'm going to have the money to buy all the subs, but not all the amps I want. I'm probably going to be able to pick up half of them. The problem I'm also facing is that if i do that, I'll be running at a 2 ohm load vs a 1 ohm load when I do pick up the rest of the amps. But at the end of the day, the beginnings will help to break in the subs, and by the time I'm able to pick up the rest of the amps, my thought is, that a little rewiring and they'll wake up pretty damn well.

I appreciate everyone's input. I'm learning some stuff. Hopefully someone else will benefit from this as well.

[Krakin]

So lowering your resistance can increase your power consumption by your subs. That doesn't mean more power equals louder either. You will also increase your losses when lowering resistance as you increase the heat (power directly mean heat)

To answer your question, yes whenever the amplifier is producing more wattage it is "working" harder. Things become bad whenever your output voltage is being pushed to where it is trying to cross over the point where it wants to be a higher potential than the voltage rails of the transistors.

You get instantaneous wattage from the RMS of the voltage. This will describe it the best (page 11ish)

https://www.google.com/url?sa=t&source=web&rct=j&url=http://www.ee.ic.ac.uk/hp/staff/dmb/courses/ccts1/01400_AcPower.pdf&ved=0CEAQFjAKahUKEwjstaO75PTGAhWT74AKHVkkBzE&usg=AFQjCNGjK0cEt_ttyXnGR8OK4dVk-u3TsQ&sig2=sxwKKYUITHTYbvMfh0j3Ww

The goal for electronics that are in the consumer level right now is to stay cool. Generating heat is against that, obviously. However in our hobby it has been thought that you can only get loud by how much wattage you have. While it is true that wattage adds decibel output (1000W is going to be louder than 10W) most people refuse to look into acoustics. Acoustical loading is a free way to gain an astronomical amount of decibel output. This however takes time to both learn and start to get right in your build. My best bet for you learning acoustics is by first learning enough about electrical signals that you understand it easily as acoustics, in my simplified explanation, is just 3 dimensional voltage and amperage.

After that the most I can recommend is reading, as reading is 'free', you can also do some experiments on your own, but without measurement devices it is fairly useless as your brain isn't good enough to tell you what decibel something is.

[gckless]

I suggest you do some reading about electricity and amps. This is a good place to start: http://www.bcae1.com/

Not putting you down, many people are in the same boat you are. But once you understand the fundamentals, a lot of things fall into place. You'll suddenly realize things people have been saying (and possibly saying incorrectly), and you'll have a bunch of those "well this should have been common sense" moments. For as much as we deal with it, it surprises me how little the fundamentals of electricity are talked about.

[scooter99]

Thanks man. I've got it up and getting ready to read now.

[Krakin]

I'm pretty sure at the beginning of that link it states to not move on through it without understanding what it just said. FOLLOW THAT SUGGESTION.

[scooter99]

I'm pretty sure at the beginning of that link it states to not move on through it without understanding what it just said. FOLLOW THAT SUGGESTION.

I will. I'm actually going to restart it at home. I already have some questions. I'm a questiony type of guy. It helps me understand things better. It helps calm my ADHD too. LOL SQUIRREL!!!!!

[Krakin]

Literally don't move to the next page until you understand it.

[Broke_Audio_Addict]

Efficiency of the driver plays a big part in it too, a lower power handling higher efficiency driver can be louder than a higher power handling driver with lower efficency.

Also most people don't realize how little power they are actually Using and how much is being lost as heat.