*Bump*

Also interested in the final details. Even a general rap up would be great. Especially, I'd like to hear how your harness is doing. Any resitence burn or signs of potential for failure? I truly hope not. I ask because the size wire you used for the pass through wires is smaller than recommended by some other MINI DIY projects. So, as I am just getting to the harness construction part....I wanted to see if 10 gauge or 12 gauge wire is overkill or right where I want to be for those four pass through wires.

Also, Do you notice not having the rear speakers?

Cheers!

 

Tom,

Excellent write up. I have been reviewing your thread multiple times over the course of several weeks and after long research went ahead and purchased same components for my system. However, I will do one thing different.

Your wiring design will feed amplified speaker signal back into stock harness which will carry the signal to the speakers. Thing is, OEM wiring is only about 22 gauge and, I am afraid, way too thin to handle 40+ AMPS produced by Alpine amp per channel. Thus, I will be running a separate 16 gauge wire to all speakers.

 

That's because most people that are "car enthusiasts" don't even have a basic grasp of electronics. 10 or 12 gauge is overkill for most subs, let alone a component set. The OEM wiring is fine, even if you're running a larger, aftermarket amp for one reason, the amp doesn't dictate how much power is flowing, the speakers do. Realistically, his speakers will never see more than 15-20 Watts on anything resembling a regular basis. If you REALLY feel a need to redo the wiring, anything more than 16 AWG is a MONSTER waste of money.

 

Thanks for pitching in and bringing some clarity. I came to the conclusion that 16 gauge is more appropriate than 22 gauge by studying charts dealing with wire length and power loads (do not have link handy right now). I am definitely not looking to pump loud music loud through the new speakers, just want more clarity and better response at higher volumes. So you believe 22 gauge is adequate to handle amplified signal? I also wonder whether cars equipped with HK use same gauge of wiring.

 

The problem with most of the charts are what they're assuming the wire will be carrying. A speakers will be receiving almost entirely AC Voltage. Of course there is some current but it's far less important in this case than the Voltage.

Whether 22 gauge will handle it will be determined by the volume levels you seek and ultimately that's what will dictate how much Voltage your amp will send out. Even a 2000 Watt amp driving your speakers will only put out 50 Watts if that's what your listening habits require.

I'm sure the HK system is probably upgraded to 18 AWG or so but at the power levels it's making it wasn't necessary.

What I'd do, unless you REALLY feel the need to run new wires all the way into the doors would be to run new wires to the connector in the kick panels and use the OEM wires into the door and then go from there. The shorter the run the more capacity a cable has.

 

A couple additional points.....

First, the factory speaker wiring is actually 0.75mm, which is ~20AWG. The factory speaker wire is the same guage in all MINIs regardless of factory system (the 2010+ HK's use a smaller gauge than previous systems for the run from HU to amp, but that isn't relevant here).

Second, there are three possible areas of impact of wire size - Voltage Drop (power loss), a reduction in Damping Factor (the ability of the back EMF to control the speaker cone movement, especially around the natural resonance frequency), and an impact on Crossover Frequency Points for passive crossover networks.

In this case, Voltage Drop is the least of your worries. Assuming (for the MINI) 15 feet of 0.75mm wire and a 4 ohm minimum load, you are looking at about 5% reduction in voltage, or only 0.2dB. You'll never hear that.

The other two items are bigger concerns, and may or may not be significant depending on the amplifier, total amount of wire, location (if any) of passive crossovers, and the details of the speakers in question. Unless you know the output impedance of your amp you can't calculate the Damping Factor. However, with the assumptions above you are looking at about 0.2ohm of series resistance in the wire, which is going to reduce ANY 4 ohm system to below the recommended DF of 200, which will start to have a significant impact on total system Q. If you are designing the speakers you can allow for this....otherwise, the speakers will either be underdamped (boomy and muddy) or overdamped (taught and flat with minimal bass) to varying degrees, depending on the specifics of the installation.

The series resistance of the wire also affects the crossover point. Adding resistance DECREASES the crossover point. Using the assumptions above, and assuming you are mounting crossovers outside of the doors (mounting in the doors presents a whole different set of problems), you could easily move crossover points by 250Hz. With a first order (shallow 6dB/octave slope) crossover on a tweeter this can be a very significant impact, and not in a good way. The higher-order harmonic distortions (the ones your ears really hear) can increase dramatically. There can be other meaningful impacts in terms of lobing, cancellation, etc. This is probably one of the most overlooked yet significant issues in high end car audio. I can't tell you how many times I've seen high end "installations" where the crossovers are mounted in the trunk in some "showy" location and a long runs of wire are required to get to the speaker. Even with larger gauge wire this will add .2 to .5 ohms of series resistance, moving the crossover points by 250-500Hz. The only way to do this correctly would be to rebuild the crossovers with new capacitors and inductors.

This is another example of why speakers, amps, and components are not really modular, as prevailing wisdom (pushed by aftermarket manufacturers) would have you believe. The series resistance MUST be considered in any complete system. Any engineer working for any of these manufacturers makes assumptions when designing a particular product, basically a one-size-fits-all (or most) approach. But there is a big difference from one vehicle to the next - the length and gauge of wire in a Ford F-150 pickup might be significantly different from that in a MINI or a long sedan. What's worse, you'll never find the assumptions listed on any spec sheet or product literature, because doing so would limit the potential customer base for a given product, so the manufacturers keep silent, and the vast majority of installers and virtually all of the general public don't know any different. If you are spending a few hundred bucks on a modest upgrade, these issues aren't a big deal. But if you are spending $1000 or more these are real issues that have meaningful impact. Getting them right can have a bigger impact than spending several hundred dollars more in higher quality components, and getting them wrong can make your $1000+ system sound more like the few hundred dollar modest upgrade.

A car system is NOT like a home system, where the components themselves are to a large extent modular. This is not least because the components are in larger chunks. Speakers, for example, are complete units where location (relative to each other), type, number, specifics, and crossovers are all one complete, controlled, coherently designed unit (at least if they are done correctly). This is decidedly NOT true for cars. The only way to get a comparable system is to design it specifically for the vehicle. This is what we are doing with our Soundstage upgrades, the first of which is for the MINI. It's not shipping to the general public yet, but hopefully by or around years end.

 

I hope someone can help me with this. I looked through the thread but didn't find this info.

On the connector behind the kick panel, not the speaker wire one but the one that has the power/ignition wire, does anyone know which wire is the accessory wire?

I just had an amp installed and it was wired to the ignition based on the info the threadstarter provided but after driving around with it for a bit, I'm starting to realize that I'd like the amp wired to the accessory 12v instead of the ignition one, otherwise the amp only turns on when the car is running. Sometimes I like to have the radio on for a few minutes without the car running.

Can anyone help me with this? The car is a 2011 Mini convertible, R57. Thanks.

 

I'm not sure what you've actually connected to, but you want to tap pin 1 of the X15 connector, which carries the Rad_On signal. This signal is +12V whenever the speakers may be called upon to produce sound: on unlock, when a door is opened, etc. the wire is 20 ga solid black.

You can find more detail in the installation instructions for our subwoofer system (or upcoming soundstage) on the Integral Audio website.

 

Cool, thanks. I'm going back to the shop some time tomorrow or next week and I'll have them take care of it. Is it the only solid black wire on that connector?

Also, do you have any idea why I am getting some engine/alternator whine coming through the amp? They tried putting in a noise filter attached to the line level converter but it didn't take the whine away.

 

Sometimes while I was asleep last night I had a thought.... Is it possible that the engine whine I'm getting is caused by whatever ignition wire he tapped into as the turn-on wire for the amp? I'm tempted to take the panel off and see if I can fix it myself.

::edit:: Ok, took care of rewiring it. Was easy enough. Ironic that 20 years ago car stereos was a hobby of mine and I'd spend entire weekends installing stereos in my car and friends' cars and now as I've gotten older I'm afraid of working on my own car. It's not so much that I can't take it apart and do the work, my biggest worry is not being able to put the car back together!!!

Anyway, I rewired it to the black wire on pin 1 of the connector and now the amp turns on whenever the radio is on whether the car is running or not.

But unfortunately, it didn't fix the alternator/engine whine. Any clues about that? BTW, if it helps, the amp I'm using is a rockford fosgate Punch P400. I have it set to 2-channel input and I'm feeding it from the head unit's front channels using a line to RCA converter. From the amp I'm running some pioneers on the amp's front channels and the sub on the amp's rear channel bridged. The car's stock rear speakers are still running off the stock head unit.

 

The alternator whine could be a few different things. It's NEVER fixed with a filter. It can be band-aided, but that doesn't fix it.

Which amp do you have and how exactly was the signal tapped for the amp?

 

The amp is a rockford fosgate punch p400.

The power cable is running straight from the battery with an inline fuse. It's grounded to a bolt under the rear seats.

The inputs are running from the front channel outputs of the head unit. They used a speaker to line level/RCA converter. So head unit > line converter > inputs on amp.

 

Check this out.

http://www.rockfordfosgate.com/scrip...%3Afaqs.faq_id

Looks like the inputs are differentially balanced so the LOC isn't needed and is probably causing your issue. Some Arc Audio amps will do this as well. Remove the LOC and solder RCA ends on and plug straight in and I'll bet the noise goes away.

 

Hrmm...interesting. So from what I'm seeing in that diagram, the RCA negative has to be connected to the head unit chassis? Can it be connected to anything else like a ground somewhere? I have no idea how I'd even access the head unit chassis without taking the dashboard apart.

 

I'd go the radio chassis. You can just use the chassis for the CD player. Sure, it won't be easy, but it's the right way to do it.

 

Ok cool. Thanks a lot for this info! Very helpful. I think what I'm going to do is print it out and take it to the shop that did the install and suggest they try this.

 

Any time. Let me know if that does the trick for you.

 

Ok, I tried it myself and couldn't get it to work. The biggest problem I had was trying to figure out how to ground it to the head unit's chassis. Tomorrow I'm taking it back to the shop that did the original work and hopefully they'll be able to figure it out.

 

Does anyone know which wires in the X15 harness are the power and ground wires for the head unit?

 

Neither of those go thru the X15.

Ground is thru the X9331 Pin 9 and then to the X13812 Pin 15on the back of the radio.

+12 VDC is directly from the Junction Box Electronics (fuse box) connector X11009 Pin 9 to the X13812 Pin 12 on the radio.

 

Thanks. Good to know. Is there some kind of schematic that shows this that I might be able to get my hands on or did you figure it out yourself?

btw, I got the car back from the shop and while they did reduce the whine, it's still not 100% gone. I guess it's tolerable for now. If the radio is on, even at low volume, you can't really hear it.

And when the radio is off the only time you hear it is when accelerating.

I think that rather than have them keep using my car as a guinea pig I'll leave it as is and maybe later on see if I can fix it myself.

Also, I showed them the service advisory from rockford fosgate that Quality Sound pointed me to. Hell, I even made them the cable they'd need but they didn't want to try it and said they didn't think it would work.

I was a little annoyed with that but since I wasn't 100% sure it would work, I didn't want to insist that they do it in case it didn't work and then they'd be annoyed with me for making them waste their time. I think if I want to try that solution I'm going to have to do it myself. I'll have to figure out how to get to the back of the head unit though.

 

Oh that's garbage I would NEVER have returned a car with noise. You paid them to do a job, they need to do it, without bitching about it.

 

I agree but I'm also of the opinion that the less people futz around with my car, the less of a chance there is of something bad happening to it. Every single car I've had, every time I take it to someone to have something done, it almost always comes back with something it didn't have before....a scratch, a loose panel, a strange noise, a broken panel fastener, a ding on the door, a cracked body panel, etc..etc...

Also, the guy at the shop was trying to tell me that since it's barely audible, there's not much more they can do and that this kind of noise can happen when they add an aftermarket amp to a factory head unit. I don't know that I buy that but I'm not sure what else I can do. Since you said this is common with Rockford amps, I'm not opposed to trying another amp. I was looking around earlier and came across this Kenwood.

http://www.amazon.com/Kenwood-Kac-84.../ref=pd_cp_e_4

$125 bucks, 750 watts, perfect 5 star customer rating on amazon... Any opinions on it? Do you think I'd have the same issue with this one?

Anyway, I really don't mind fixing it myself since I kind of like working on this stuff. The hard part is already done. Amp is mounted, wires are run, speakers are installed, etc..

The only issue now is how to get to the back of the head unit to ground the RCA leads there.

 

Update! The problem is essentially fixed. Fixed the damn thing myself. I had taken it back to the shop on Thursday and they tried again. I don't even remember what they said they did but it didn't do squat. They kept telling me that with the stock head unit and an aftermarket amp there is bound to be some noise. Anyway, I took it home and noticed something interesting. After I got home, I went under the dash and behind the kick panel where all the connections are and looked around. I didn't change anything but when I put the line-out converter and everything back in place behind the kick panel, I noticed that suddenly the whine was louder. Even louder than it was initially.

A spark went off between my two remaining functioning brain cells and it dawned on me that maybe the LOC and/or the RCA connectors were picking up noise from something behind the kick panel. So.........I extended the leads to the converter so that I could move it somewhere else and voila! Noise was about 90% gone and even though it's not 100% gone, it's to the point where I can live with it.

I ended up mounting it under the dash right next to the center console and I think that should finally do the trick.

If I'm ever inclined to get rid of that remaining 10% of the noise, I can always run some longer speaker leads from the head unit to the trunk and do all of the connections back there to completely eliminate any electrical noise it's picking up from whatever's around the kick panel area.

 

I agree with quality_sound - there is no excuse for them returning the car with alternator whine. A proper installation should have zero audible alternator whine. Them saying that this "just happens sometimes" is laughable. It does "just happen" - but only if they don't understand the problem. I'd be curious as to their response/explanation if you told them that an Integral Audio's system in the same car has no such noise.

Without getting into too much detail, it is helpful to understand what you are hearing. When your car is running, it doesn't have true direct current like you get from the battery. The alternator creates an alternating current, which is rectified (turned into) direct current by a bridge rectifier. This "direct current" is really a series of pulses that vary in frequency with engine speed. The variation above the DC level is called AC ripple. This is what you are hearing and why it changes with engine speed.

That's what you are hearing. The why has two possible causes. The noise is either being introduced directly into the signal path, or it is being magnetically coupled into it. An explanation of the two is more than I can get into here. The first cause is the most likely, but if moving the LOC changes the noise it would be the latter. This would be more likely if you are using a LOC that uses transformers. Did you try moving the LOC back and forth while connected and the car was running? Did the noise get worse when closer? What is the brand/model of the LOC?

Regardless, the LOC isn't necessary. However, unless I'm missing something that RF amp does not have differential nor even balanced inputs (there is a difference between the two). The MINI HU does have a balanced output - so you can not connect the signal negative to the negative on the amp - this would short the signal ground to power ground. I believe all the MINI HU's have short circuit protection, so you probably wouldn't damage the HU, but you would shut it down.

You have two options for removing the LOC. You could replace the RF amp with an amp that does accept a balanced input (and ideally is differential), like the ARC amp that we use. The easier option, though, is to remove the LOC and try connecting a 10k ohm resistor inline with each negative signal input. This will only fix your problem if the cause was option 2 from above, but if moving the LOC reduces the noise, then this is indeed your problem.