Dammed

Tell your father this, if he's a mechanical engineer he should feel a little bit embarrassed by stating that question. No hard feelings. I'm also studying to be one actually. When your bass starts hitting really hard the amplifiers in the back will take power from the battery in the back, the alternator does not see this at the moment. Your front battery starts to charge the battery in the back becuase the battery in the back has a lower voltage since it's discharged. The alternator sees this and starts charging the front battery. This happens in a fracture of a second. Since the cables on the front battery are contacted to the top, the electricity can flow around the front battery, in a way it will almost bypass the front battery and it will charge the battery in the back. Meaning after the first discharge of the back battery, the alternator will charge it almost directly. You can compare electricity to water. The batteries are buckets and the wires are pipes, the alternator is a pump. When you take out some water in the back "bucket" the water pressure gets lower here, the front "bucket" will then send some water back in an atempt to equalize the water pressure, the pump will then notice the loss in water pressure and starts pumping more water into the system. This is really simplified, but in a way it's how it works. And no you will not destroy your front battery, but you will over time (very long time) damage it if it's a normal OEM battery, becuase those can't handle the abuse of the car stereo. That's why I recommend you to buy a Shuriken front battery since this is meant for daily car stereo abuse. edit: And if he does not believe the "punk ass teen" on the forum, ask him to ask a car electrician. They will probably say this: Your car stereo system will use more power then the alternator can replace, this may damage the alternator over time becuase it runs at 100% almost all the time, but your alternator will not damage your front battery. This is a fact, that's why people buy HO alternators so that the alternator can charge the batteries back up. For you the cheapest way to solve this is to buy a good INTELLIGENT battery charger that can charge AGM batteries, and then you plug the charger in to charge your batteries when your car is off. Maybe you don't need to do this, but it is advised.

Yeah I thought about that to. But what about the resting voltage, isn't it pretty low on batteries like that? In the setups above, the most expensive battery is the XS Power 2700 at $299, so no $400/700 batteries here. No I'm not a show guy, but I will try to make the stereo look really good. The batteries will be under the enclosure, I was thinking about making a big plexi window to show them, but if they are ugly then I'll just skip the window. Hmm, I was expecting more replies then one. Nobody has some advice regarding this?

If you have very little money, buy the smallest one. if you have a ok amount of money, buy a battery with the same ore more AH rating as the starting battery you are using now. if you want the best, buy the biggest battery you have room for under the hood.

If you want to keep the starting battery in the front and use the Shuriken in the back then you should use a isolator since the resting voltage is much lower on your starter battery. What will happen is that Shuriken battery in the back will start charging the starting battery until it's discharged to the resting voltage of the starter battery when your car is off. Now this will be a problem in the long run, since AGM batteries don't like resting at a low voltage. If you replace your starting battery with the Shuriken BT-120 you bought, then I think you'll get a bit low voltage at the amplifiers int he back. And you will loose some AH since you're not using the battery in the front. The best thing you can do is to buy another Shuriken battery to replace the one in the front and use the BT-120 in the back close to the amplifiers. This way your ESR will be about the same and the batteries will not charge each other (to some extent). You will get a higher Ah rating in the system, and your voltage at the amplifiers will be higher.

I have to resurrect this thread from the dead. Is this a real problem or some BS? In Norway where I am from the Kinetik batteries have a bad rep becuase some, quite a few actually, say that the Kinetik batteries can't hold their voltage. Odyssey batteries are quite popular, and most people recommend using those batteries. I started to search for "battery" in this forum and found this thread and I started thinking, is this maybe the source for the bad reputation that Kinetik has in Norway? And I use a Ctek XS 25000 intelligent charger that I have noticed has charged up to 15V sometimes, these chargers are quite expensive and most workshops here use these chargers, will it be a problem to charge a Kinetik with this charger? Charger Link I have a HC800 in the front and a HC1800 in the back and I'm going to be running a Iraggi 180A alt as well so this info is quite valuable for me. edit: I have also noticed that almost all battery manufactures recommend maximum 14.4V charging on their batteries.

This build is great! Gives me a lot of tips on how I should build my wall. God job guys!

of course, but when the heat leaves the heat sink it will travel straight up. If you have the amp sideways then the heat will travel alongside the heat sink and block off the cold air that's around the amplifier. Now like I said this is a more technical POV, becuase air moves and when air moves around in a car then the heat will follow the air and it wouldn't go straight up. But even so, I would say the best way to mount a amplifier would be flat. But I and many others here have had no problem with mounting amplifiers sideways. so it shouldn't be a problem. But if you get heat problems, try mounting it flat or adding a computer fan or two.

heat travels straight up, so from a technical point of view you should get better cooling if you mount it with the top facing upwards and bottom down. From a practical point of view, it doesn't really matter that much. I have had a Hifonics amp mounted sideways and it never over heated.

ok, thanks a lot for the help. I think I'm going to go for a S1200 in the front and two D2700 in the back. I want to have a big battery reserve so that I can play a little bit with my engine turned off, and I want my electrical system to be ready for any huge amplifiers in the future that might come. This electrical system should be able to sustain 10.000W rms.

there are many batteries that can't be used as starting batteries. They have maybe enough CCA/CA but if the electrical reserve is not high enough you can damage the battery when you pull to much from it. Deepcycle AGM batteries shouldn't be discharged more then 50%. So if it's below 0 outside, you have a little bit weak CCA and you use the car a lot during the winter to do small trips to the store. Then you'll probably discharge it below 50% if you do not use a battery charger, this will shorten the lifespan of your battery. I have used a Kinetik HC800 as a starting battery on my 1.8l engine, it works ok, a bigger battery would be better. Especially if you have a big engine. you can read a little bit about battery types here: Deep Cycle Battery FAQ

true. But if you have to few and/or weak batteries the voltage drops quickly below the resting voltage. IF you have many enough, then they can sustain a voltage much closer to the resting voltage for a short period of time. So my question would be, how much below resting voltage will it drop if I have only those two batteries? I mean there must be a reason when people buy and use 8-10 Kinetik HC2000 batteries in the back. And one thing I have also wondered about, is it better to have 3 smaller batteries or 1 big one? The combined AH and Ampere would be the same of the 3 smaller ones and the 1 big battery.

nice, very nice. My goal is to be running above 13,5V at full power with my HO alternator for at least 1-2min, do you think this will be possible with only two batteries (D1200 + D3400)? Or is this goal achievable at all?

I bought a P800PRs from a online store, but they managed to send me the old version P880PRS. And since I live in Norway it's a big hassle to send it back to the US. Except from the black frontplate on the newer model and the copper plated chassis, are there any other differences between those two models?

I did search but I didn't see it the first time. Is it this thread you were thinking about: Pioneer 880prs vs. 800prs - SSA Car Audio Forum ? And it seems like the P880PRS is bluetooth ready even if the specs on Pioneer homepage doesn't say so. I checked the manual for the Bluetooth interface, and it does indeed say that P880RS is bluetooth capable. It is the basically the same model except copper chassis and the black frontplate. thx guys.

They don't know, the new model will be available from march. Yeah I know about the radio, the radio stations end on uneven numbers like 107,7 in the US but they end on uneven and even numbers in Europe. So you can't get some stations. But that's no problem, because I never use the radio and because it costs a lot more then the US model. I have to pay $1015 for that model in Norway. If I import it from a different EU country I can get it for a about $845. A lot more expensive then if I buy the US model. But just to check something, the seller is obligated to cover the return cost if they ship out the wrong item. Right?

Hmm, I think you misunderstood me. The new model P800PRS is bluetooth ready, but you still have to buy the bluetooth interface. The older model P880PRS is not bluetooth ready, so even if you bought the bluetooth interface it wouldn't work. It has the 24 bit burr brown D/A. Look at the 2nd line under CD player: Pioneer USA - DEH-P880PRS - Superb Sound Control and Clarity just got Better with our New CD Receiver Yeah I want to send it back as well, problem is almost no one has the P800PRS in store becuase they are discontinued. But I'll call them and check if they can get hold on one, because I simply love the new black front plate.

I called Pioneer USA and they said the difference is the two I noted above, and the older model can't have Bluetooth. The P800PRS can have BT if you buy a adapter for it. Which is kinda important for me, becuase I want to buy a adapter later on for my phone.

hehe sounds cool. So how did you connect them to the amp? And yeah, pics!!!

Man you must be on drugs or something, the only question you ever asked me in this thread was why I think 28hz is logical in a car. And I replied to it, saying that Fi recommended it, and I have stated that I have no experience with vented enclosures. So I can't 't give you any other explanation. My loss? Please, you may have some good knowledge about car stereo but to believe that someone is lost/damned without your almighty guidance that's just sad. And like a taxy cab driver said in a old classic, fuck you to my friend. bigjon, I have allways wanted one 18" subwoofer, pretty much cause it's rare and I have allways wanted a big wubwoofer, I used a 12" in sealed enclosure cause I didn't have enough money to buy something better. As A college student, money is a bit short. I'm going to make a variable slot port, so I can make my box tuned from 20hz til 40hz with a 2,5hz variable, so who knows, I'll maybe end up with a 35hz tuning, or maybe even a 25hz tuning. The reasen for 20 odd hz as you put it, is that if you tune the enclosure very low, the Q's will be having a much more flat output. Here you can see the difference between 20 and 40hz: 20hz: 40hz: I get a much louder setup with a 40hz tuning, but I believe that with a 3200W rms amplifer and two 18" in a small celica will be more then enough loud for myself. But for DB contests I'll probably tune the box to 40hz and see how loud I could play. Dude, don't believe what M5 is writing, if you looked back, I thanked all the replies I got, except M5's becuase he's trying to do a some Freud shit. So yes I care what other people think, and I consider every advice I get.

How is a statement like: "Whatever you do, don't put them in a ported box tuned to 28Hz that won't help you at all... " helpful when I don't know why you say it. I even asked you several times to explain why you think so, and you have answered 3 times without doing so. The first time you replied back I got the question thrown back at me. The 2.nd time you said you will not spoon feed be the answers. Hmm, any answer would be good. Not a spoon fed one. The 3.rd time you almost repeated the statement by saying: "28Hz won't fit your goals" The 4.th time you said I have a bad attitude. (If I understood you correctly) One or two posts in this thread from me was a bit fired up, but the rest of time I try to keep my replies as neutral as possible. And I don't have a bad attitude towards people trying to help me. I might be having a bad attitude towards you, but do you really find that so strange given your first statement and then your replies after I ask you to explain your first statement?

you know there is a thing called google you know. for the subs, take a look here: JL Audio - Car Audio Systems This is not the same link as Impious posted. Exactly what amplifier do you have? If you have the manual, then take a look inside, it should say how low impedance it can work with in bridged mode and in 2 channel mode. Then you look at the link I posted above and check out what wire setup will give you the most power without using lower impedance then what the amplifier can handle in bridged / 2 channel mode.

I will be posting a build thread when I get started, but like I said I will wait until the temperatures rises a bit since I don't have at the moment any place to work inside. I have to deaden my car first as well. I understand WinISD, I was just looking for some confirmation. But I got that from a different forum. He maybe full of knowledge, but that fact is useless for me if he doesn't share his knowledge. I'm here to take advices and to learn to make my own choices. Simply stating it isn't for me becuase he says so is not good enough. I stopped taking advices like that after I turned 10 years old. Because in the long run, it doesn't help me one bit. A ported two 18" wall is a big step from one sealed 12", and who knows I'll maybe take water over my head, but I like challenges and I'm good with tools and wood. And I'm in no hurry, I have driven my car without a car stereo for over 6 months, and I can survive at least 6 more months. I will be building a variable slot port, so I can tune from 20hz to 40hz in 2,5hz intervals. I only have to remove one subwoofer to change the tuning. So If I find out I have tuned to low, I'll just remove a section and get a higher tuning. For now it seems like it will be a 28ft3 enclosure with a flared 10" x 20" port, length will vary depending on the tuning. And before anyone starts to rant about the port, it's more then big enough. The air speed through is low enough with any tuning from 20 to 40hz. So it will not make port noise with a regular port, since I'll be making a flared one I'll should 100% safe from port noise. The Q's will be in a very big enclosure, but they like big enclosures. The Xmax is within limits so it should not be a problem. The enclosure might very well change down to 20-22ft3, I have to figure out the final design, but it will be a big enclosure.

lol, did you even click on the link Impious posted to you? It's all explained there. look at the picture below the headline: "4 DVC drivers with Voice Coils in Series / Parallel" You will then get 2 ohm to your amplifier.

M5, the time I care if a forum person laughs at something I wrote/did is the day hell freezes over. I think for myself, but since there are many aspects to tuning it's kinda hard to know what specific thing you're thinking about that will give me some problems. I understand the point to not spoon feed people. Goes under the concept of teaching someone to fish rather then giving them a fish. But can you at least narrow down the field. Should I be looking at the SPL curves in WinISD, cabin pressure, driver properties, car peak frequency, the list goes on. If you're thinking that I will not get loud at 28hz, then that's no problem, I'm not looking for loudness, it would be nice, but a good sounding system is after all my first priority. And as I see it, if I tune it even lower at 20-25hz I get a much flatter curve in WinISD, meaning that the subs will not peak and that will be giving me a better music experience. If I have understood this correctly. But if you don't want to help me out, don't get all warm and fuzzy inside, there are people out there that will.

thx guys. now, the last question: Why is a 28hz tuning a bad idea?