QuestionQUESTION: i'm trying to find the hardest hitting subs that i can put into my expedition. i have 2 rockford p3002 amps and alot of space to fill. Could you please give me some insite and opinions on what, how many, what size subs i could put together with these amps?
ANSWER: I don't make equipment recommendations. Why? Because the choosing is very subjective. And, the most subjective of all are speakers. Further, what sounds really great in one vehicle may not sound good at all in another. How they acoustically couple into the cabin of a vehicle is related to the acoustic loading effects. Example, one of the best low frequency, hard hitting systems I have had are two 8 inch jbl drivers in small cabinets in a 4 door Audi. Those same speakers when transferred over to a Pontiac Firebird did nothing extra at all.
I suggest you study the reviews and opinions online but make your purchase from a retailer that has a liberal return policy in case you wish to exchange them for another model.
JL and Kicker are good for the money.
Alpine are good, Infinity, --- and well, many others.
In fact, there is nothing wrong with Rockford subs, as well.
I would be curious to know what you decide.
C
PS: For simple and easy installation, easy to take out when you need the room for other things, take a look at Bazookas. Some of them sound really good in SUVs.
Two of these
http://bazooka.com/products/mobile/Passive-Bass-Tubes-Subwoofers-C7/BT-Series-S6
one on each amp will do good because they are 4 ohm and would get a maximum transfer of power from the amps you already have....... But this is not a recommendation; just a thought.
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QUESTION: C-
would 2 rockford p3002 amps have enough power to run 2 rockford p3 subs? from my exp. with rockford amps I think they are rated way lower than what they actually put out. I would greatly appreciate your advice.
Thanks-Link
AnswerI disagree. Rockford amps put out good. I would not be afraid of using them for the system you describe.
We have a tendency to get too power or wattage anxious, especially in mobile installations. We, as consumers, have been too quick to just read the advertised specs and get all worked up over the flimsy list of technical items offered by the marketing department of the products we are considering to purchase. The reality is as follows:
- Power ratings for speakers is primarily a cleverly prepared work of fiction. There is no universally accepted standard to measure the power ratings for a speaker. (But there is for sensitivity; see below.)
- Whereas, power ratings for amplifiers are based on a very specific set of scientific documents and is a very objective piece of data. If an amplifier is tested by 5 different testing laboratories for power output under specified conditions they will all get the same results. There is no guess work or subjective factors involved.
- The power figures are illusive and misleading anyway. Let me explain. It is easy to assume that a power amplifier that is twice the power of another will sound much louder. Take, for example, an amp rated at 100w. Then replace it with an identical amplifier that is rated at 200w. It will play twice as loud. Right? Wrong. Here is why: The human ear hears non-linearly. Twice the power input to a speaker is a 3db increase in level. If you test a human for loudness change by asking the respondent to indicate when an increase or decrease in level is just enough to detect the answer will most often be 2db. Remember twice power is only 3 db. SO: Increasing the wattage of a system from 100w to 200w will produce the capability of increasing the perceived sound by just a little more than barely noticeable. NOW: Lets say we want to test the human hearing this way: We increase the power until the respondent says it sounds twice as loud; or conversely, we decrease the loudness until it sounds, to the ear, half as loud. The answer? In most humans it is very close to 9db. HOWEVER: 9db is very close the 10db which is a power factor of 10! What this means is that for our system with a 100w amp which we want to increase the sound pressure output level so that it sounds twice as loud we would need an amplifier of almost 1000w!!
- Therefore, the easiest way to get a greater sound output from a system is to use loudspeaker with a higher sensitivity (a figure that IS quite objectively tested and reported fairly accurately by the manufacturers) by 3 or 4 db. If a speaker has a sensitivity of 88db and it is replaced with one that has a sensitivity of 93db it will sound much louder - with the same amount of electrical power going in.
- However, in order to get more sensitivity from a loudspeaker it must be designed with lighter parts and stronger magnetic fields, etc. This changes its performance and alters the sound quality. As a very broad and general rule, the lower the sensitivity the better low frequency response it is capable of. Thus, there becomes a trade-off between sensitivity and low frequency thumping power. That is why the big show cars use huge power amps - to compensate for speakers with very low sensitivity - but better super low frequency response in the bass.
- Finally, how the speaker is mounted in a box and how that acoustically couples into the listening space is a very complex mathematical equation, but the subjective result is drastically different for different spaces; especially this is so in the mobile environment where the cavity cubics and shape are so different from one vehicle to another.
Sorry for the big lecture, but I thought this would help you understand the dynamics of your system.
Best wishes,
C
