snafu

Loud and linear = good Loud and non-linear = listening fatigue

No. http://www.stevemead...of-a-subwoofer/ Be sure and read Ray's reply in this thread (on page 1). Vd is really what you want to compare.

Read the whole thread guys . . .

I see Rusty lurkin' . . .

Good one . . . I thought I knew 'em all . . .

I'm going to have to take issue with this one. If the manufacturer specifies a minimum operating impedance (they all do), and they don't tell you on the phone - "well, you can actually run that amp at half of what we say . . . " (most don't), then follow their guidelines. Most all amplifiers have protection circuits that are designed to PROTECT the output devices from failure when they are asked to pass more current than they are designed to handle - such as what happens in a dead short or in cases where the amplifier is connected to a load with an impedance below what the engineers intended it to operate. In other cases, the amplifier won't actually go into protect, but it will reduce it's power accordingly to prevent failure of the output devices. I've been in and around car audio since 1983. This is one thing I will NEVER understand. Why so many people think that they can, could, or should operate an amplifier outside of the parameters set forth by the company that designed it is baffling. If you own an amplifier that is rated to produce 1,000 watts into a specified impedance and you desire to operate into half of that impedance, what you really need is another identical amplifier. But, guess what? This is widely understood at the design level at most companies that make a living selling amplifiers. Most make the assumption that the user will attempt to operate the amplifier at 1/2 of the impedance it is rated. SO, they design protection circuitry to protect the amplifier from damage when doing so. Let's make this simple - IF you attempt to operate an amplifier at 1/2 of it's rated impedance, you will likely have troubles. But, if you're one of those people that shifts well after the needle on your tach is in the red zone, I guess you'll just have to find out the hard way.

That's way cool. The instructor is Brett Farquharson, owner of AudioMotive - the South African RF distributor. He is one of the most passionate car audio dudes I've had the pleasure to meet and incredibly knowledgeable. If he endorses a product or idea, then rest assured it's best in class. Great work guys.

Now, that's a testimonial!

Both Rockford Fosgate and JL Audio have free apps that you can download via the apps browser on your phone that have all kinds of cool tools. Everyone should download both. No, their SPL features aren't the last word in accuracy, but they can be fun to play with.

Correct, you simply discharged the power supply caps by shorting the + and - power inputs. No damage should have occurred to the amp, but I bet you jumped!

Unlocking this topic so Sonic can address with the OP.

http://www.stevemeadedesigns.com/board/topic/14953-rockford-t15k-the-proto-pics-and-short-story-more-pics/ This is an excellent read for those of you that have not read it.

supercap = industry terminology for carbon capacitors The 50 Farad and 100 Farad RF and LA caps were the first to use this technology, prior only available in the power generation industry - think power generating windmills. That was back in like 2002 I believe, so it isn't a new idea by any stretch of the imagination. I ran one of the 100F caps in my Mustang for years and it worked excellent with 3,000 Watts RMS - as in ZERO [Edit: MINIMAL - lol] voltage fluctuations with music at full tilt boogie. I removed it because I wasn't driving the vehicle very often and those big caps have a bit of a parasitic draw (100 mA or so) when you let your vehicle sit. Over time, this resulted in a dead battery. Since I removed the cap, my dash and park lights look like a rolling disco (headlights are HIDs so voltage fluctuations do not affect them). The infamous T15k uses three entire boards of supercaps, but they are used to supplement the high voltage rails (I believe they are +/- 70 Volt!), which is why it behaves like no other power amplifier. Look closely at the formula for energy as it pertains to capacitors - (CV2)/2 and you will notice that capacitance is really not nearly as important as voltage . . . look what happens when you leave C the same and change V from 14.4 Volts to 70 Volts . . . So much to learn . . .so little time . . .

Likely to increase their voltage capability. For example, the old RF 100 Farad capacitor was really (6) 600 Farad caps wired in series. Why? Simple - each cap was rated at 2.6 (or 2.8 volts - can't remember . . . )

The answer is simple and it only applies to quality capacitors, of which the Rockfords are. Assuming the capacitor is properly sized for the job and located within 12 inches of the amplifier . . . would you rather have 12.6 Volts or 14.4 Volts available to your amplifier? It's just that simple. So for all you guys that say caps don't work, I would challenge you to learn more about the topic. Hint - start by learning about pulse width modulation and how the power supply of a car audio amplifier works. Hint 2 - read the sticky in regards in the RF forum. With so much good information available on this topic, ignorance is not bliss.

Wow . . . just wow . . .

Workin' on that now!

That IS a sexy beast!

Well, I don't disagree with any of it personally. Loud music doesn't offend me, but not everyone feels the same way. Cruising down neighborhood streets at 2 AM with the windows down and the system up just isn't cool. Having said that, I was constantly in trouble (and subsequently met many of the members of local law enforcement) when I drove the demo vehicles around as a rep . . . but that was a long time ago . . . It is our right to have thousands of watts in our vehicles. If we choose to abuse that right, then we have problems. I think it's important to keep in mind that those that do NOT have an appreciation for the thumping of a passing "boom car" greatly outnumber us. And honestly, we may not enjoy it too much either if we'd never experienced what that's like in the vehicle. Now, on a lighter note, enjoy the following public announcement from Chris Rock and note the part about loud car stereos . . . one of my favorites!

For many years, I used to demonstrate how to use an o-scope in my trainings, and I traveled with a lab grade scope. Even guys that had been installing for 20 years were intimidated so most said, "Yeah that's what we should do, but . . . " If ONLY we had tools like these in those days. Even some of the trainers I worked with were like . . . dude - it took me all morning to get the knobs and dials just so, DON'T MESS WITH IT - the training is in 5 minutes. This just goes to show you that you need a profound understanding of these type of tools to maximize them. Unless you're a propeller head like me, it's like magic to get a waveform to appear on a lab grade scope. The handheld scopes like those from TPI and Fluke are far superior for USE and portability as they auto range time and scale. They are not however superior as measurement devices. The DD-1 bests either because it's BETTER at the intended job. Now I got news for you, even a lab grade scope is simply is unable to do with the DD-1 & CC-1 can do as a pair. For example, when you use the DD-1 & CC-1 together to set up multiple amplifiers, you achieve something not possible otherwise. Not only are the amplifiers gain matched to the tee, you are also able to eliminate phase shift caused by the individual settings of each of the amplifiers' crossover controls. Imagine 12 amplifiers, all slightly out of absolute phase with one another. Now imagine those same 12 amplifiers absolutely IN phase with one another. Which do you think will be louder? The DD-1 and CC-1 are in my opinion the two most significant tools to be introduced to the auto sound industry in the last 20 years. Buy them. Less time trying to figure out how to use the tool = more time to smoke cigars and drink Pacificos . . . now, that's a WIN WIN.

Why do so many people use red wiring for everything? Red = 12 Volts OR Speaker (+) . . . Buy some black or clear wiring for your Grounds and Speaker (-) leads and that will save you from all kinds of heartache down the road . . .

Guys, that's a BUNCH of horsepower to the pavement - like equivalent to that of a new Corvette Z06. 'Zat bottle empty yet? LOL . . .

Steve - of course you're talking 140mph on closed roadways . . . . New technology + old technology . . . you just gotta' love it!

Get a new girlfriend.

BTW, I must say it looks like you have chosen a VERY capable shop Steve. Get a brotha' some pics of any bad-ass muscle they got around there.