rockford fosgate p600.1bd to much power

speakermakers wrote: So that your suggestion. Under power? Ok! Great I guess? You go with that

It's absolutely IMPOSSIBLE to "underpower" a driver. Period. Read here. Dude, this stuff has all been gone over ad nauseum, here. TRY READING THE STICKIES! jonchos, the 325 watt option on your 400 watt woofer will be fine. As far as "what's better"? AFAIAC, running a HIGHER impedance is better as it results on lower heat, lower THD, better efficiency. Sure there's the "less power" issue in there, too, but if you are running your highs amp at 4 ohms, and your sub amp at 2 ohms, that'll be just fine. Read my sticky, here, that'll explain my opinion again.It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."

Here I am in a situation where I have to argue both sides of a debate in order to set things straight. First off, I should start by pointing out where haemphyst was right. He caught my repeated typo (it's head room not over head). Give haemphyst a rubber tortilla for his aptitude for editing. Also, even though haemphyst did not word it correctly he is fundamentally correct that you can not over heat a voice coil by grossly under powering. But I did not say that! I said “Also keep in mind that a 325W RMS amp on a 400W RMS sub does not provide you with any protection. You can still burn the voice coil if you run the sub at distortion. Clipped sign waves produce a lot of heat”. Many people make the mistake of misunderstanding what RMS power is as it pertains to an amplifiers output abilities. The Root Mean Square value describes an amplifiers output ability at a fixed load over a single cycle (usually 1Khz) of a pure sign wave input (which has a constant RMS/crest factor of its own). With a crest factor of 1.414 and a corresponding constant RMS value of .707. Music does not have a fixed RMS/crest factor even within a single track. The RMS output of an amplifier playing music over time is constantly fluctuating. It's not what the manufacturer stated it was. But the max power abilities of the amplifier is constant for a given load and does not fluctuate with the input signal, that does not change. The real question here is how much power will an amp produce on average over an extended period of time playing real world music. If you know that and you know much power it will take to over heat your sub you have a good idea of how much abuse you can dish out before failure. Scenario 1: The reason why a 325w RMS amp can fry a 400w RMS sub. According to a study conducted by JL Audio and presented by Mark Eldridge at the MERA Knowledge Fest of '07 the average crest factor of this decades recordings is an astoundingly low 9.8db. I quote “If the listener cranks it up further and clips Godsmack by 10 db, which is not uncommon, the amplifier will produce almost its full rated power as an average power level”. That means that the 325 RMS amp can produce about 450 watts over an extended amount of time. Mark Eldridge also stated during that same training, and I quote “excessive power applied over time burns coils”. A 325w RMS amp can maintain over 400w of power over an extended period of time under normal circumstances, and I haven’t even factored in the variable of the bass boost feature that is built into that amp! Scenario 2: This is the flip side of the situation. High quality recordings have crest factors that approach 20 db. This means that the RMS power reaching the speakers is about 1%. That means that with a 325w amp only 3.25w RMS is reaching the speaker! The other 99% of power is reserved for sudden bursts of sound. This is a good thing. If you have a large enough of an amp you can reproduce huge dynamic qualities in the music. This gets you closer to live sound. Even though less power is reaching the speaker at RMS the sudden transition from a small sound to a huge sound creates an impression of power. Big time. This immediately raises the question, “How much power can I squeeze by this speaker before damage brings my ever increasing performance to a sudden halt?” Technically the answer is, until the RMS value reaching the speaker exceeds the RMS value of the speaker. On the surface this sounds like we are back where we started, but now we know that the RMS output of an amp fluctuates. It is dependant on the program material and never exceeds the max power abilities of the amp. I must point out that the term “RMS power” is BS. It's short hand slang coined by the U.S. amplifier standard known as IHF A202 back in ’79. I use it here for argument sake, but it does not in any meaningful way qualify an amplifiers performance. In order to properly judge an amplifiers performance you have to factor in many more variables such as transient power, power averaged over time, and power with all channels driven. This will give you a better idea about the amplifiers power supply and response time. The answer to "how much power", is simply more than you need. It's just like deciding how much power you need for a drag racer. The answer is more than you need. Are you running the risk of damaging your speakers? You bet! The volume knob is your throttle and you have control. If you here something funny or smell something funny, TURN IT DOWN! My experience has been that enthusiasts are just that enthusiasts. They want all the performance that they can get their hands on and that performance comes with a measure of responsibility. Haemphyst you have repeatedly warned me about posting here, and you have repeatedly thrown personal insults my way. I will post here when ever I want and I will never ask for your approval. You have a lot of valuable information to share with others but your poor attitude is a disservice. Check the tude at the door. I come here to learn and share. You should do the same. Unless you are above the rest of us. I am happy that I am learning to create better posts because there are so many people on this site who know what they are talking about. The reason I post is to obtain better written communication skills. That way I can help more people better and with more efficiency.