Wicks

With audio being as subjective as it is, there will always be different stories, true. You can tell amp architecture difference in sound? or by the means that A/B is less efficient so the excess power affects the system? Impressive regardless. Lots of amp companies nowadays with full range Class D amps that say you can't tell the difference. Yes, running at 4 would be ideal in the fact that Class D amps at 4ohms are like 90% efficient so you save a lot on power loss at the very least. As you state, running 20-30kW at 4 ohms would get rather pricey wouldn't it.

Yes, damping factor drops with speaker impedance, by sheer definition. DF = Zload/Zsource. Half your speaker load and you half your DF. Most modern amps today have DF in the hundreds if not thousands. Half that and you're still very high. I've read tons of articles that say that with DF's in the range of 20-50 and you'll never notice a difference. Sure, an amp will technically have "less" control at lower impedance but if its designed to handle 1 ohms loads then will that lead to noticeably poorer SQ? SQ people out there? Open for discussion?

This "article" is nothing but a big advertizement for JL and Alpine, not that there's anything wrong with them. Of course if you load a 4ohm rated amp down to 1 ohm, it will be stressed, overheat and have poor SQ. An amp that's designed to run at 1 ohm should not have any issues running at that load, but that's never mentioned...strangely. A legit unbiased article should not need to advertise certain brands of equipment. It should also not need to be a big instruction manual on how to wire a sub(s). Read the comments at the bottom. The writer does nothing but suggest that the people buy JL and Alpine equipment...

My DD-1 is ordered! Hey Meade, any chance you could sign mine too...please? Also picked up a hat and beanie...gettin' cool over in Colorado. Can't wait to try it out. Order# 100000807. Jamie M. Fingers crossed for the second giveaway...

^^^ Like was mentioned above, there are MANY factors that play into this but on the theoretical note: Doubling power = +3dB Doubling cone area = +3dB You're not quite doubling the cone area by going from 12" to 15" but you might be close with either solution. Again theoretically +10dB is considered to be perceived as being twice as loud. This requires increasing power by 10x... I say do what makes you happy and go with it.

Hard to tell without a schematic, but it looks like one of the power supply FETs are shorted. Causes a large current draw when you connect power to the amp, hence blown fuses. Needs a pro to troubleshoot and repair. The FET could be swapped but its hard to tell what caused it.

Grew up to Heav in highschool. Some of the first rap I heard at the time. RIP. If this classic stuff from the 90's doesn't put a tap in your step then you got issues...

Looks like its stuck in process for a Senate vote, if ever. The website doesn't give you a good idea if when the next steps are going to happen.

^^^This! Options: 1.) Buy new equipment. 2.) Use an impedance matching transformer between the amp and speaker (not ideal and costly). 3.) Only power one of the voicecoils at 1 ohm. Not ideal either. 4.) Run equipment at lower power with 2 ohms.

Not to rain on your parade, but the FETs should probably all be replaced... Different lots of FETs could have different series resistances. More current will flow through the least resistance, so if the new part has a mis-matched resistance from the others then it could blow again...

so if i replace all 3 of those the amp should work again? and where would i even get ones to match? FETs would be the only component to produce the black residue when it fails. Resistors would show a burnt ring around it and the cap should be fine. It would be a great idea to replace all three. With one part failed, the others could be stressed. Looks like the FET shorted or blew. Look at the number on the other FETs around it and do a search on Digikey.com. Look up "resistor color code" to find out what value the resistor is. Or use a DMM and measure one of the other resistors. Look at the printed number on the cap and look that up as well although its probably fine.

Theoretically, With doubling your power from 500W to 1000W, you get +3dB. Doubling again to 2000W gives another +3dB. Doubling your cone area, another +3dB. Total = +9dB. There are MANY other factors that play into this as well. Box type, box size, cabin gain, EQ settings, etc...

Hey, its a theoretical calculation... Real life implementation is another story.

Sound energy is logarithmic and not linear (equal increase in power = equal increase in loudness). The formula for a power ratio is: PdB=10Log (P2/P1) = 10Log(2Watts/1Watts) = 3.01dB. Therefore a doubling of power equals roughly +3dB. Acoustically a gain of 10dB is perceived to be twice as loud. PdB=10Log (10W/1W) = 10dB. As you can see it takes 10x more power to reach a +10DB increase. Therefore a system with 150dB will be perceived twice as loud as one with 140dB...

There were lots of comments in Trippi's build log with the horizontal lexan box. Lexan should be chemically bonded to other lexan: http://www.eplastics.com/Plastic/Lexan_Polycarbonate_Glue Looks like IPS #40 is the way to go if they use it for aquariums. I saw plenty of comments that lexan shouldn't be screwed at all. Not sure the best way to bond lexan to MDF...? Maybe the same stuff.

Food for thought and not necessarily true. Wikipedia lists MDF with a density of 700–850 kg/m3. This converts to 0.7-0.85g/cm3. Polycarbonate (lexan) is listed with a density of 1.20–1.22 g/cm3. So lexan is more dense that MDF. If its more dense then I would assume that it should be harder to vibrate and work just as good, if not better, than MDF. Given that its braced and sealed like any normal box would be.

A normal wall outlet is rated for 15A from the circuit breaker panel. Roughly 120VAC * 15A = 1800W (purely resistive). Verify that your power strip is rated for 15A (most are) and you should be OK. You'll probably want the amp on a separate circuit from the rest of the system (if possible). A house room would probably be on only one circuit though from the breaker panel.

Your amp does 800Wrms (rated). Its Class D so a ballpark 80% efficiency means it pulls around 1000W. Given a 13.8V supply, you're looking at 72amps of draw (not counting other amps, etc). That's maxing out your alternator. So you are using some reserve from your batteries a lot. Your 4ga wire to the amp is also rated for only about 80amps so you're at the limit of the wire too. Increasing to 0 gauge wire would help a lot, along with a bigger alternator (and the battery that you've mentioned).

Last xmas I bought an AC distribution block with a wireless remote. Used it to turn on xmas lights on my patio. Got it at Target. Its basically a power strip with a wireless remote. Pretty handy. It was weather proof too (if that matters).

No prob, glad I could help. Post up some pics when its done, curious to see how the LEDs look. Thinking about doing some similar myself shortly.

Whoa...only need a fuse at the source. If you find an open slot in your fusepanel, throw in the 10a fuse there. Then route the wire to the trunk. If I understand your setup correctly: Battery >> Main fuse >> fusepanel >> switched output >> 10A fuse >> relay >> junction box >> LEDs and amp turn-ons. The 10A fuse is meant to break the connection if a wire down stream would come loose and short to ground causing a large current to flow which would burn up the wire. These components that you're connecting themselves dont fail to a "short condition". Basically if your LED strip breaks or fails it stops drawing current, same with the amps. Therefore they don't need seperate fuses themselves.

Gotcha. So you're running the switched power wire from your headunit to a relay to turn on amps and power some LEDs. The remote wire (from the headunit) should already have a fuse inline. Usually from the backpanel of the headunit. If not, it wouldn't hurt. That turn-on wire will only be powering the coil in the relay so a 1a fuse would be plenty. The switched power wire that is running the headunit, relay and accessories should come from your car's fuse panel and already be fused. It will probably be fused for the headunit only though, so more draw through the fuse might be an issue. You're only running amp turn-ons and a LEDs so I highly doubt it but I need to throw that out there. Does your car's fusepanel have spare fuse outlets? Those should also be switched with the key and allow you to fuse that line seperately. I still don't know what the LED current draw is but LEDs draw very little power. Amp turn ons will also be low power, depending on the amp. To be safe and allow for enough expansion, a 10a fuse should be plenty. What size wire are you running from said terminal block to the trunk? 14ga like you mentioned for the remote turn-on? 14ga is good for around 20A so fusing at 10A will be safe.

Not sure I followed everything you wrote. 14ga is plenty for a remote turn-on (assuming that you're using it to only switch items on and not power anything). Remote turn-on leads should already be fused from the Headunit. Always use RMS ratings, max numbers can be highly exaggerated and lead to the wrong size fuse. Do the amps already have fuses? If not, their manuals should state what to fuse them at. Amps aren't 100% efficient so they will input more power then they output. Therefore you have to take that into consideration when fusing. Do you have a multimeter that can measure current? You could use that to measure how much current the LED strips are pulling. Depending on how many you're running, LEDs use very little current so without knowing what you have, a 5a fuse is probably fine. Where is this relay sourcing its power from? A distribution block in the trunk or a seperate power wire from the battery?

i didnt run any fuses on the jumpers or the amp turn but for the lights i would fuse them... i know when i will buy my lights and install them i am going to run a fuse. if i am wrong about not fusing the amp turn on hope someone tunes in and corrects me. edit: also you would need to fuse the relay #87 to 12volt source though All wires should be fused at their source. This protects the source in case that wire comes loose and shorts to ground down along the cable run. Power distribution wire should be fused to the gauge of the wire. It supplies many things and you want as much current through it as possible. If it shorts to ground though you want the fuse to blow before the wire heats up and causes damage. Amplifier power inputs should be fused to the rated current draw of the amplifier. You allow it to draw its maximum rated current, but if the amp fails and draws more current then its fuse blows before doing more damage to the amp itself (and anything its powering). What lights are we talking about? LEDs, light bulbs, etc. Find the power rating of all the lights in the circuit and divide by the max voltage (12-14V). This will give you the total current draw that the lights require. Match that with the corresponding fuse.

Batteries should have an output current capacity rating. If you want to run the system full tilt without the alternator running, then make sure you have enough batteries to supply the current required. Batteries also have an Amp-Hour rating which tells you how much "power" the battery holds. A battery with an Amp-Hour rating of 20AH will supply a current of 10 amps for 2 hours (10a * 2hr = 20AH). So just use that formula with your batteries to see your capacity.