GlassWolf

between the two, and not using any isolated battery just for the audio system? the XS.

aiming a sub the above link may help. also in regards to downfiring subs, this may also help: Percentage of Sag = 24,849 / ( Xmax * Fs²) If Sag% < 5%, the driver may be mounted down (or up) firing. (Xmax in milimeters.) downfiring works well in SUVs and sedans generally. just use legs or similar design to elevate the box about 6" off the floor of the vehicle.

on a side note, consider a battery backup for the alarm, or a battery backed-up siren for the alarm if you plan to use the car's starter battery for the alarm system. It's too easy to bypass an alarm a couple of ways when the starter battery is in the factory location and used to power the alarm system.

the bit on the welding was information I'd garnered from welding data on automotive work from restoring old cars, really, but it applied to this in part. The data was in regards to resistive spot welding of sheet metal (joining subframe to floor pans and such.) I've been looking around the net, but most of what I find isn't on specific measures of electrical resistance. The data I'm finding is more to do with tensile strengths of welds, and the electrical resistance changes of welds from liquid to solid during the weld process. I'm outside of Columbia, in Lexington. Just moved here last Fall.

I haven't done any personally, no. That testing was done with welding research for automobiles, but electricity is electricity, and it applies to this situation as well. I apologize for not having anything from the internet to provide a link. That data as acquired before the internet was quite so prevalent. I'll see what I can find on-line when I have the time, though. Anecdotally, if you observe the higher levels of SPL competitors however, you'll note that very rarely will you ever see anyone using a chassis ground for their amplifiers, instead choosing to ground directly to battery bus bars most of the time. I guess that's one of the problems of being older than the Internet.. haha Not everything I learned came from a computer. lol While I don't consider this valid "research" I can say that higher SPL numbers in controlled environments have been attained by using direct to battery grounding vs chassic ground in high current applications with SPL competition vehicles by myself and others, too. The same goes for using multiple ground runs vs single runs. SPL is a bit of a goofy thing.

well personally, when the engine is running, I'd be sure the alternator was up to the task for the current demands. The batteries really shouldn't play a part in thatwhile the car is running. If this is for sanctioned competition, or use while the car is shut off in parking lots and such, then I'd have a normal starter battery, a battery isolator so that the starter battery is never seen by the audio system, and dedicated batteries in the back, in parallel, with as low a Peukett Exponent as possible, and sufficient amp-hours to support the audio system demands based on current draw at the desired volumes, for the period of time required, and I'd be sure to use deep cycle AGM batteries to avoid issues with gassing if the batteries aren't going to be in a sealed battery box, vented to outside the car. When you start putting batteries in the passenger cabin of a car, you start getting into the risk of gassing, and possible health issues related to the inhalation of hydrogen gas.

the alternator charges the battery(batteries) when the engine RPM is above idle, and voltage is higher than that of the batteries themselves. When the car is running, and above idle, the alternator supplies current to the car, and the battery should be in a charging state. some notes on electrical systems check the link above, under the "Electrical" heading. Some of those links may prove informative.

yeah I'm one of the admins of CAC.

This isn't specific to Kinetik, but generally with racing batteries (I use one as my starter battery) a racing battery is lighter weight, sometimes 16 volt, and high CCA. These batteries are designed to save weight in track and strip cars, as well as being designed to give high cold cranking current for high torque starters on high compression race engines (think 11:1 or greater compression ratios on big blocks) They also typically cost a fair amount more than a typical lead acid starter battery.

No, frame is good, wire is better. This I have to agree with. With modern subframe cars (not full frame cars) your car is really held together by the subframe in the front, which is joined to the rest of the car by spot welds and floor pans and such, which have the equivalent current capacity of approximately 4AWG wire. If you're running a high current setup, the best bet is to run dedicated, isolated audio batteries (parallel, busbars) with the amplifiers connected directly to the batteries (or via distribution blocks) at both Pos and Neg terminals. Skip passing the ground through the chassis (don't confuse the terms "chassis" and "frame.") Most modern cars also do not have a single frame that runs the length of the car. Heck, my car from 1966 is even a sub-frame, or at least was until I welded in the subframe connectors to link the front and rear halves to reduce chassis flexing at launch. It had the added benefit of giving me a good place to run cables, too though, once it was all boxed.

Fuses. Understand how they work.

some notes on speaker size I jsut wrote this one recently. If anyone sees any errors, I'd be happy to hear thoughts. Anyway I thought it might help on the sub question.

If the amp has a really good power supply, and it's not a regulated output, you should see double the output going to half the load. In reality, some amplifiers have a regulated output so they produce the same power at both 1 and 2 ohms, while others just don't have the power supply to support that sort of load so they only put out maybe 60% more power at 1 ohm over 2 ohms. That said, the electrical differences on paper anyway would be higher distortion (THD) and lower S/N ratio, worse damping factor and less dynamic headroom and reserve power. Will you actually be able to hear these things? Very doubtful.

pretty well put. the transformer (toroid if it's a good amp) gets the power straight from the 4+AWG wire that runs to the amp, and usually directly to the power supply. (I have some pics of the guts of my Orion 2250SX amps if needed to illustrate this) The power supply converts high current 12VDC input power to what's usually 70 volt, or multistage output to the output FETs, which are where your heat comes from (at elast in a class AB amp anyway) which are generally bolted directly to massive bus bars that run the length of the amp (I can provide pics of these as well if you like) to soak that heat and transfer it to the heat sink or case of the amplifier (this is why big amps have big heatsink fins running their length, although with class T and D amps, these aren't as necessary since they are about 80-86% efficient vs an older class AB amp with like 60% efficiency) The power traces on the internals of amplifiers are suually huge, and very wide on a PCB, and higher end amps tend to stick with the old tried and true "through-hole" technology which tends to allow for a lot more power flow than smaller SMT boards and components could. That's why we still see big caps and transistor packages in amplifiers, whereas head units are all 4+ layer SMT boards these days to cram more into less space. Anyway in short, the guy was feeding you a line of crap. I can disprove him in a matter of moments with an oscilloscope, a tone generator, a dummy load, a regulated power converter/supply (110VAC to 12VDC high current) and a DMM.. or in other words, my test bench. If the amplifiers couldn't produce their rated power, sustained, they wouldn't get a CEA2006 rating that states they produce their rated power under very specific standards. Now what you could argue is that the rated power can't be produced in a car because you have an inductive load in an environment subject to impedance rise, transfer function, cabin gain, dynamic input source, and other factors like that.. but that really is a different argument, and not directly related to what the sales rep was trying to feed you. In truth, most sales people aren't electrical engineers, or even certified installers so what they tell you is what their marketing people cook up and feed them to regurgitate to buyers who aren't educated enough to shoot holes in their BS. When I worked for a shop in the early 90s, we had a PG rep come by and try to talk us into selling his stuff. Now, I like Phoenix Gold, or I did back then anyway, but he started spouting off about hte amp having no minimum load spec, so just to see if his claim was true, we wired the amp up to the test board, then proceeded to wire up 8 2-ohm 12" Orion 12" subs to the amp, in straight parallel. We cranked the volume and turned on the Alpine CD player.. The amp played! ....for about 2 seconds, then smoke poured out of it. We unplugged the amp, returned it to the sales person, and tahnked him for his time, and his new door stop, and sent him packing.

Don't rely solely on Ah as a means of measuring a battery for car audio applications. this may help: car battery sizing for audio applications I actually just posted the above page this week because I've been seeing this topic pop up quite a bit recently.

What electrical system upgrades are you using? HO alternator? Is that Optima in the trunk isolated or just run parallel to the starter battery? How are the amplifier gains set? (most common reason amps shut down like you describe is from clipping due to lack of current, of the input stage being over-driven.) The amp rack looks great.. from the front If you want some really slick fans that will help with airflow, google "PAC CF-1 FAN" You'll get a result of my favorite car amplifier fans. Give those a try.

a garage and vigilance is a good start. Additionally, Viper, Python (DEI companies), Alpine if they still do security systems. I used to love their stuff. CompuStar as well (I use their flagship model in my current car.) Here's some ideas for you, This is the system I set up in my previous Jeep. I don't really like to share details of my current security setups.

use Sirius or a digital TV tuner with a head unit offering AUX input like this: digital TV tuner

a few links that may help: Charging systems The Big 3 Battery Isolators Sizing batteries to match your audio system The ratio of power to volume explained There's no real way to tell the amount of power your amplifier is supplying based on the volume or bass knob, since a "1200 watt" amp is rated by the manufacturer with a resistive load on a test bench with a stable power supply and a full spectrum pink noise test tone input at full output, whereas you are using the amp with a dynamic input source, in a car cabin subject to factors like cabin gain and transfer function with a subwoofer that's a reactive, inductive load in a box subject to impedance rise, while the speaker itself varies in impedance based on the frequency it's producing, and where half the audible volume from full output is equal to a tenfold drop in power output, and so forth.. you get the idea. The actual power output of an amplifier in a car is typically nowhere even remotely near what it's rated power is on the amplifier case. Also of note, you shouldn't really be relying on batteries to power the audio system when the engine is running. As long as your alternator puts out a higher voltage than the batteries, it's the alternator's job to supply current. If the alternator isn't large enough to accomplish this task, then it needs to be upgraded. Good luck!

battery size calculator battery isolators I wrote these to answer your questions. I see the same questions pretty often. hope these help.

300A alternator & external regulator 300A Battery Isolator Sears DieHard 875CCA Gold starter battery Kinetik Monster 2400 isolated audio battery 1/0 AWG power distribution Pioneer Stage-4 DEX-P99RS head unit Orion 2250SX amplifier (300WRMS x 2 @ 4 ohms stereo @ 14.4VDC) DynAudio System 360 front stage (8" midbass, 3" midrange, 1" silk tweeter) mounted in custom fiberglassed kick pods Orion 2250SX amplifier (1200WRMS x 1 @ 4 ohms bridged @ 14.4VDC) Fi Q18 subwoofer, sealed @ 4 cubic feet Cooling, I Heat Ring, High Qts, Spider, dual 2 ohm coil options Compustar 2WSS-AS alarm system May go fully active soon using an Orion 2150SX on midbass, another 2150SX on midrange, and a 275SX on tweeters

Components TV/Monitor Samsung PN63C8000 - 63" plasma 1080P F3DHD HDTV (May 2010) AV Receiver Onkyo TX-NR5007 THX™ Ultra2 Plus™ Certified 9.2 Channel Network Receiver Onkyo UWL-1 - Wireless USB Audio Transport Onkyo UP-HT1 - HD Radio Tuner Amplifier on KEF mains Krell KSA-200 DVD Panasonic DMP-BD55K High Definition Blu-Ray DVD Player DVR HR23/700 DirecTV HD DVR & eSATA ext. HDD 1.5TB includes Multi-room and On Demand via 802.11n wifi LDP Panasonic LX-H670U multi-beam laserdisc player VCR Toshiba W808 6-head HiFi S-VHS recorder Turntable Ion USB belt-drive turntable Tape deck Nakamichi DR-1 Discrete 3-head tape deck Control Logitech Harmony 900 Universal RF Advanced Remote Power APC Line-R 600VA Line Conditioners APC Back-UPS 600 UPS Speakers 7.1 A/V speaker setup KEF Reference Series 104/2 Raymond Cooke Limited Edition mains, bi-amp (type SP3128 matched pair, bi-wire, rosewood finish) Pinnacle P-5.5 center-channel Polk Audio FXi3 dipole surrounds Polk Audio FXi3 bipole rear surrounds Energy e:XL-S12 powered subwoofer 2.0 audio critical listening Aragon 8008BB amplifier KnuKoceptz Karma SS 10AWG speaker wire 10' each, with eKs banana plugs Martin Logan Vantage mains, cherry finish Iinterconnects KnuKonceptz Karma SS speaker cables, 12AWG bi-wire, eKs BFA banana plugs (mains) KnuKonceptz Karma SS speaker cables, 12AWG, eKs BFA banana plugs (center, surrounds, room 2) KnuKonceptz eKs interconnects (subwoofer, RCA, optical, digital coax, s-video, HDMI) Furniture custom 5-shelf A/V rack, tempered glass shelves, spalted maple and red cedar cabinet Dayton LCD60-TM Tilting TV Wall Mount Illuminaire main speaker and Plasma TV backlighting PLX318 and PLX318-LB x2 Z-Wave full home automation via Harmony 900 remote

OK, I wrote this response recently to someone else asking a similar question, but it seemed to fit ehre, so I'm quing to paste what I wrote, then add a few notes to it. Now with that said, I'll answer two questions I saw when glancing at the responses, too. Regarding the over-EQing of the source material, the OP did state that the source signal would not be clipped. You're also still limited to the line voltage limitations of the source, which in the OP's example is 3 volts. There are physical limits to the sine amplitude that the source can produce. Anything more gets clipped. This leads me to the second thing. "What's the deal with line voltage? Why is more better?" Simply put, the higher the line voltage, the lower the noise floor, and the more resolution your source signal will have. Think of your source signal like a JPG image, and your amplifier like PhotoShop. The more you take that JPG (the source signal) and blow it up in PhotoShop (your amplifier) the faster you see how high of a resolution the original JPG (signal) really was. If your original signal is 500mA, when you amplify it, you only have so much signal resolution to work with. If the source signal was an 8 volt signal (Hello, Eclipse.) then you have a better signal resolution to work with when it's amplified 500 times. I hope that helped some.