GolfGTIforum.co.uk
General => Car audio => Topic started by: B-chi on 18 June 2009, 20:52
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Well i've finally got off my ass & have uploaded the latest install pics, so thought I'd do a build thread.
First up the front.
(http://i369.photobucket.com/albums/oo137/B-chi/Golf/IMG_0461.jpg)
(http://i369.photobucket.com/albums/oo137/B-chi/Golf/IMG_0463.jpg)
(http://i369.photobucket.com/albums/oo137/B-chi/Golf/Picture286.jpg)
6.5 inch comps running off 180wrms a side. Alpine HU running 3x amps & ipod ai net box.
Couple of pics of cable running & such.
(http://i369.photobucket.com/albums/oo137/B-chi/Golf/Picture256.jpg)
(http://i369.photobucket.com/albums/oo137/B-chi/Golf/Picture257.jpg)
(http://i369.photobucket.com/albums/oo137/B-chi/Golf/Picture258.jpg)
(http://i369.photobucket.com/albums/oo137/B-chi/Golf/Picture259.jpg)
(http://i369.photobucket.com/albums/oo137/B-chi/Golf/Picture269.jpg)
(http://i369.photobucket.com/albums/oo137/B-chi/Golf/Picture270.jpg)
(http://i369.photobucket.com/albums/oo137/B-chi/Golf/Picture272.jpg)
I've run uprated knukonceptz speaker cable throughout. 12awg from amp to crossovers behind the glovebox & 16 awg from crossovers to doors. Tweeters in standard location & mids in standard location but I will be fibreglassing the back to add strength.
If anybody wants to know how to do the big 3 or run cables let us know & i'd be happy to help. I've also fully deadened the inner & outer door skins with loudboy (from TA) sound deadening.
Next up the boot.
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The boot!
(http://i369.photobucket.com/albums/oo137/B-chi/Golf/Picture285.jpg)
(http://i369.photobucket.com/albums/oo137/B-chi/Golf/Picture281.jpg)
(http://i369.photobucket.com/albums/oo137/B-chi/Golf/Picture288.jpg)
(http://i369.photobucket.com/albums/oo137/B-chi/Golf/Picture283.jpg)
This is the second boot build, wasn't happy with the first so redid it.
The rails are gripfilled to the boot floor. The battery floor is attached via the spare wheel stud. Then I screwed the amp floor down to the rails, fitted the amps & dizzy blocks, & wired the 2 batteries up together.
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Nice, must do something like that with mine, I`ve still got the original, and it`s sh*te!!!!!!!
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Nicely done mate.
Did you gain anything from doing the big 3? Any pictures or tips to do that?
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Keep this updated chap, I'd like to know how it turns out, I have a lot of free time on my hands this summer so was going to do some sort of boot build for my car :)
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Well its been a while since of updated so here goes.
The electrical tape is only temporary, but shows what ive done. I do feel I have seen an improvement. Playing music loud & i mean loud she doesn't drop to below 13v. Batts float between 12.8-13.1v. So there hardly being touched.
(http://i369.photobucket.com/albums/oo137/B-chi/Golf/IMG_0488.jpg)
In this pic it shows the battery earth in the standard location. I wasn't completely satisfied so drilled a new one just next to the battery.
(http://i369.photobucket.com/albums/oo137/B-chi/Golf/IMG_0484.jpg)
(http://i369.photobucket.com/albums/oo137/B-chi/Golf/IMG_0487.jpg)
(http://i369.photobucket.com/albums/oo137/B-chi/Golf/IMG_0486.jpg)
(http://i369.photobucket.com/albums/oo137/B-chi/Golf/IMG_0485.jpg)
Ideally I could run another run of 0awg straight from the alt to the batt as well. I've run out of 0awg though.
I've also changed what I'm running now. 1 of the monos has gone & all 4 powerplants are up for sale & i'm building a monster box for 1 12inch nv. The box is inch thick with a double baffle, subs recessed, 30inch long slot port, neutrik speakon connections. It's going to drop. Will get pics up as soon as the box is finished.
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Nice clean work in the boot mate, nice to see you have taken your time on this and got the results that show all your hard work.
A few questions and pointers about your wiring though, I hope you dont mind some advice :wink:
What batteries have you used on this? I ask as they look like marine batteries, marine batteries are not really suitable for this application as unlike automotive batteries they are designed to take long slow discharge until nearly flat and then recharge, they are not really suitable for heavy duty discharge and charge like this.
I cant see a fuse on your feed to the amps where is it?
This looks like the standard alternator, in which case the cable you have used us way over the top as the standard alternator only pumps out 70 amps max and that is when it is new and only for short periods. So that cable is about 10 times bigger than you need. You would be much better connecting the alternator output directly to the battery rather than adding an extra connection to the starter, we all know how quickly the starter connection gets covered in cr_p and spoils the connection.
You did solder all the connections to your power leads didnt you?
Running the speaker wires so close to the instrument cluster is not a very good idea as you are likely feed interference to the instruments that could affect their accuracy and even the life of them.
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All those amps and only got front door speakers?
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The batteries in question are sonneschein a512s. Sealed gel deep cycle batteries. There capable of putting out 2 & a half thousand amps over 5 secs each. That's what the spec sheet says anyway!
Although the cable is over the top, the thicker the cable the less resistence thus meaning less voltage drop. That was my understanding of it! I'll also be running a seperate cable straight from alt to batt as well.
I was under the impression that soldering large cables can make them brittle when terminated via crimps. Fir this reason only I haven't soldered. Most of my other connections have been soldered.
Didn't know that about cable runs near instruments? Not sure which other way to run them.
@Len. I've now sold one of the monos & only have one sub not four. It was 2 monos for the subs & one 2 ch for the front.
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But where are the subs? I see no pics of them which is why I asked the question!
Your thread title implies its the whole car! :rolleyes:
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My laptop has died so I can't post up pics. I did have 4 powerplants but was only running 2 of them & I've now got a fusion nv in a 3cuft box tuned to 30hz. made from Inch thick mdf & a 2 inch baffle with the subs recessed in.
I'll see if I can email the pic to photobucket.
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[IMG]http://i369.photobucket.com/albums/oo137/B-chi/Golf/photo.jpg?t=1247658818[IMG]
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Thanks for the reply.
Deep cycle batteries are what some people call Marine batteries, they are not ideal for this use and not much good for starting cars on a regular basis either, I just hope this helps someone before they buy the same type.
There is a lot of missunderstanding about electrics, its not voltage drop you get from high resistances its current drop, there is a big difference between the two.
Going big on the cables does reduce resistance and allow higher currents to flow but go too big and they become too stiff and can suffer from fatigue fractures internally where the engine moves for example. As there is a maximum of 70 amps from the alternator regardless of the cable size going that big is a waste of time and money, something to remember for next time.
Regarding soldering, its an urban myth that its not a good idea to solder, all joints should be soldered, just crimping any connections is not a good idea and can cause crackling and poor performance due to the higher resistance connection - allways solder all connections, crimps are only for connectors that must be removable.
Thanks for taking my posts in the way they were intended, just trying to help :wink:
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I thought marine batteries were designed to withstand salt corrosion and that they can be deep cycle or engine start or both. How else would they start boat engines? Also these batteries are suited to large ups battery banks. Where they'll be discharged then recharged & kept floating until there discharged then recharged again.
If The current goes up, doesn't the voltage drop. If my alt puts out 70amps but has high resistence through small cable, the current getting to the battery will be less than if the cable was thicker with less resistence, surely?
Also in aerospace applications all the connections are just crimped. The vibration causes solder joints to fail apparently. Crimp connections, done properly, are better as they are pretty much copper on copper. Solder is not as good a conductor. Spoke to my old man who works with space satellites & such
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Marine batteries are deep discharge batteries, but are desiged for powering auxillary systems only, you use different batteries for starting the engines, yes I do own a boat and have 1st hand experience of this in addition to my industry training and more than 30 years of experience.
Quote "If The current goes up, doesn't the voltage drop" NO, the two are seperate, voltage remains the same throught the circuit only the current changes. Resistance causes a reduction in current flow, it does not change the voltage.
Try the following, get a multistrand cable connect it in a heavy duty circuit then cut all the strands except 1, the voltage will be the same, but it wont allow sufficient current to flow. Think of current like you would water flowing through different sizes of pipe, compare how a hose pipe and windscreen washer tubing can flow different amounts of water through them.
A lot of people are confused by this.
A few years ago I worked at Rolls Royce as a Queens Flight engineer and inspector on helecopter systems, you are correct that crimps are used in such applications, however the current requirments are lower, the cables and connectors very carfully matched, they are also subject to regular checking and testing and regularly fail and have to be repaired or replaced. A very high percentage of cables fail testing at their regular "flight hours" inspections.
You are also right that solder does not conduct as well as copper, however a soldered joint is more suitable for the hostile environment in a car so the benefit gained outweighs the very minor downside.
A properly soldered joint has a much longer lifetime than crimps and when done properly, without excess solder flowing outside the joint will not affect the strength of the joint, a badly soldered joint with solder flowing down the inside of the cable through capilary action is another matter. Its all about using the correct temperature for the solder being used and the correct size of soldering iron for the job.
If soldering was such an issue why are so many circuits such as ecu's and amps soldered inside? They dont use crimps inside the amps do they?
I specialise as an auto electrician and car electronics and diagnostics.
Eric
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Wow really interesting read. I'm an electonic engineer so can understand whats going on. Thanks for the info Eric, even tho its not my thread lol!
Loving the standard of installation B-Chi, its really nice to see things done properly for a change, the amount of bodge jobs i've seen is just unreal! Good work lad, look forward to seeing more :afro:
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I thought Current and voltage are linked, you cannot change one without changing the other. Ohm's law!
Can't deep cycle also be suitable for engine starting. I know optima do them. Doesn't deep cycle just mean the battery is capable of discharging more than a standard battery without damage.
My deep cycles havebeen working fine starting the car for the last few months. I also know people with proper big installs that have been starting cars with deep cycle batts fine for years.
When I start the car the voltage drops to just under 12v. When a big bass not hits that 2 can drop the voltage so isn't starting jut the same as a heavy bass note. It requires a large amount of current to start the engine. Well I've got upto 2500 amps on each of my batts for 5 secs!
I'm nit trying to claim to know everything. I like to learn about things I'm interested in & some of what your saying goes against what I've learnt so far.
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None of us know everything, I learn new things every day.
Ohms law is all about the relationship between voltage, current and resistance. What you are seeing is called voltage drop, the voltage should be the same throught the circuit, check at any two points on the system, if it varies at all you have found a high resistance in the circuit, that should be fixed.
The fact that your battery voltage drops is down to the load put upon it by the high resistance starter and the amps, the battery can only provide a limited output, that is where it all gets complicated to explain.
This is why there are different types of battery, made from different materials, there are some batteries that are a compromise between a deepcycle battery and high power battery that aim to provide a mid-way house between the two, most battery manufacturers offer them, but ask about capabilities and my experience has been that the answers become a bit vague, they normally suggest that you are better using the correct type for the purpose, but you can use these multi-purpose if you want.
My own experience is that the multi-purpose batteries tend to have a shorter life when used in a fast discharge environment such as starting and other high power uses like amps. I can only suggest you contact the battery manufacturer to get advice based upon the best type for the particular purpose you have in mind.
I bought 4 deep cycle gell filled batteries for my boat (at £225 each) that were supposed to ideal for my boat with 2 for starting and the other 2 for lighting, tv, fridge etc, the two used for starting only lasted just over a year, the manufacturer declined the warranty on the basis that they were only intended for occasional starting and as I was starting both engeines about 4 times every weekend that they had been excessively used.
I have fitted dual optimax batteries to a number of 4 wheel drive vehicles, 1 yellow top and 1 red top, one for starting the other for the winch with great sucess. I fitted split charge systems at the same time.
Eric
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Current drop :grin: ouch :laugh:
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On a serious note bichi, although I admit that I am inexperienced with car audio I am however a qualified auto electrician with city&guids etc, and have been a hifi enthusiast /modder / diyer for years and while everything you say about ohms law, voltage drop and keeping resistances as low as poss to minimse the dreaded voltage drop which is as relevant in hifi as it in car audio but where I disagree are your views on soldering. In my opinion copper to copper crimped connections are a no no as copper oxidises leading quickly to a dodgy connection as for solder it is not brittle it is soft, standard solder may not conduct as well as copper but specialised hifi silver loaded solder available on ebay and elsewhere is. Such solder and gold plated connectors are the norm in hifi. I can however see the practical problems of soldering in the car. If you must use crimped connections then silver plated cable (which does not oxidise like copper) and plated connectors although expensive are a must for high quality audio appliications. Your further views on this subject would be appreciated.
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@ Ian. What I've found from my own experience, research, etc is that cable termination comes down to preference.
A well crimped connection is better than a badly soldered one.
A well soldered connection is better than a badly crimped one.
Other than that 'all is fair'. I've heard/read argumens for both sides & they both seem valid.
The standard cabling that I replaced was crimped not soldered.
My cable is currently from a nuclear research facility, so is not cheap (well it was for me lol), it was crimped with proper crimpers made to be able to crimp that size cable. All it needs is heat shrink round it & I think it should be fine.
Just read that back to myself & it seems a bit arrogant. It's not meantto be, I hear what people are saying but I've decided that there is enough evidence to justify what I've done.
If I was going for an out & out spl or sq system then I would spend more time & money investigating, but as it's a daily/Ltd competition use I reackon/hope it should be fine.
I do appreciate all the comments/criticisms/suggestions that have been made, that's how we learn/get better at things.
On a side note is anyone able to sort that link out for my sub box. I'm on the iPhone & I can't for the life of me get it to f**kIng work, bloody thing!
I've got a comp tomorrow so will post up my scores & comments on tomorrows activities!
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Hi sorry if I came across as arrogant I was only trying to be helpfull perhaps you should read this. http://cs.pennnet.com/display_article/194291/42/ARTCL/none/none/1/Electrical-connections:-What-you-can-do-to-prevent-corrosion/
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No don't be silly Ian. I'll give that a read later. Went to T17 yesterday @ my single 12inch with 1100w mnaged 142db @ 34hz. Well chuffed. I also came 2nd in 120-129.9 bassrace.
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I said earlier on that I was inexperienced with car audio but highly experienced with home audio. having said that I have experemented in the past with in my opinion poor results and being content with a "mediocre" stereo in my car. My main problem is power, you talk about many hundreds of watts and I have heard others and seen specs with similar power rating, but its the 12v and ohms law that gets me. My amp in my home puts out a modest 80w rms per chanel into an 8 ohm load, but its input voltage is 80v to develop that. In a car you are resticted to 12v. I know they try to get round this problem to a certain extent by using low impedance drive units, usually four ohms but never the less. Power (watts) equals volts x amps, ok we know the maximum output voltage of a car amp is about 10v once the dreaded voltage drop has been accounted for. All we need is the amperage to determine the maximum power that an amp can deliver into a fixed load. Lets make this fixed load really low(2 ohms) and work out the amps and finally the rms. Ok to work out the amps we use ohms law which states I=V divded by R or current = volts divided by resistance, we know the output voltage is ten and the resistance is 2 ohms so 10 devided by two is 5 or 5 amps, and power = volts times amps which gives us a maximum power output of 50watts into a 2 ohm load around half that into a 4 ohm load and half again into an 8 ohm load, so quite where these multi hundred watt power figures come from I am at a loss to understand. Perhaps your self bi-chi or someone else can explain. Has anyone experemented with higher voltage supplies and amps?
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My amp, with engine on sees 14.1v (got a voltmeter). The amp in question is a classD 1100wrms mono amp. It has 4x 25a fuses. The 1100w stated will only be delivered when the amp is at full whack & seeing 14.4v so with it seeing 14.1v the output will drop to maybe 1000-1050wrms. (figure is a complete guess).
Aren't home audio systems resticted to 16a?
Car audio (12v), is restricted to the output voltage of the alternator but the amount of amps you can use is unlimited. I know guys with over 1000ah of battery power.
Some people do run 2 seperate alts. A standard 14.4v for car & in some cases 18v for audio.
A guy at the show I went to on Saturday was running 12,000wrms (2/3rds of his power ATM) that's a lot of batteries.
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First your point about hi fi amps being restricted to 16A, no the current is only restricted by the power supply for the amp and the output transistors. You say your amps current output is unrestricted but it is as I mentioned by the amps output stage but the point I was making is that the load (or speaker) determines the amount of current used (ohms law) and at 4 ohms it aint much you would need to connect loads of speakers in parrallel to utalise all that current. I suppose the small area of air in a car (one step up from ear phones) means you dont need a lot of power as 12v 14v is neither hear nor there you need 100v for real power.
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My amp is running at 1 ohm. My sub is dual 2 ohm so gives the amp a 1 ohm load.
I'm not quite following why you need loads of voltage to get loud.
Mine is loud enough to make the boot move half inch. My car stereo has always been louder than my home audio!
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voltage is power amps go distorted when the voltage limit is reached (clipping) as I mentioned earlier it is only in the confines of your car that it will be loud, in a bigger space it would be a bit lost.
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For some reason I locked the thread. Not sure why or how but finally got my laptop back.
So heres the pic of my sub box.
(http://i369.photobucket.com/albums/oo137/B-chi/Golf/photo.jpg)