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Probably not of interest to most, but - major audio overhaul

Posted: Fri Jul 22, 2011 1:04 am
by defiancecp
I've been tweaking design documents on how to put together a major audio system in my leaf since about 4 months before I got it, and now I'm actually finally getting some time to start working on it. Yay!

So quick summary of the design goals:

DESIGN GOAL 1: <10% reduction in range in most conditions, even if system cranked continuously

If we maximize time in-car driving, say 25mph average (city driving), that's 4 hours. It's possible to be in-car driving on one charge longer, but unlikely. Most other conditions will be less time, so very rarely will we pass 4 hours of usage.
Ok, so we have 4 hours, and the total pack is 24kw/h. Therefore, it's using 6kw/h per hour: 6kw continuous while driving.
With that in mind, if the stereo consumes 660w, that brings consumption in this scenario to a total of 6.66 kw consumed when driving with stereo blasting. 24kw/h consumed at 6.66kw gives us 3.6h - 10% down. from the initial 4hr figure.

Therefore, limit of additional consumed pwer is 660w. Converted to amperage at 12v, that's 55A
Of course, the system will rarely constitute that much of a continuous drain, so range impact should be much less than 10%.

DESIGN GOAL 2: minimal increase in weight

This one is pretty self explanatory, and also contributes to the idea above about not reducing range.

DESIGN GOAL 3: Minimum long-term impact on interior

Another self-explanatory one - I want to keep the interior looking as close to stock as possible.

DESIGN GOAL 4: retain stock head unit

So the main control unit is integrated with charging systems, climate systems, etc.etc.etc... Extracting it without losing functionality is implausible. Thus, I'm stuck with it.

So those all relate to the car's specific design goals, now my personal design goals (taste, preference, etc.)

DESIGN GOAL 5: stealthy install- that's just the way I like it.
DESIGN GOAL 6: <$3000 budget
DESIGN GOAL 7: Focus on front stage sound quality
DESIGN GOAL 8: retain functional rear speakers (but have them faded off when no rear passengers)
DESIGN GOAL 9: Still want nice sub system

The design I settled on involves:

-Front outputs from the stock player disconnected from speakers, and instead connected to speaker level inputs of the factory integration unit
-Alpine imprint factory integration unit converting the speaker inputs to line level, equalizing them to compensate for the relatively low quality output, controlling crossover points and time delays, and outputting to the amplifier
-JL xd700/5 5-channel amp routing 300+ watts to the subwoofers, 100x2 to the midbass, and 100x2 to the mid-highs
-Precision Power 3.65c 3-way components with active crossover between midbass and mid, passive between mid and tweet
-Midbass mounted in front factory locations
-mid-tweet mounted custom fiberglass pods in small 'door window' areas
-Rear outputs from the head unit driving polk coaxials (can find the model number if needed) with external crossovers in the factory location in the rear door

So the components have been here for weeks waiting for me to start, but when I first tried to get started I just couldn't do it - it's been 100+ just about every day for over a month, and the garage was bar studs & rafters with siding/roof... meaning it was 5-10 degrees HOTTER than ambient.

So I spent about 2 weeks insulating and drywalling. No I've got r13 in all walls, insulated garage door, r49 in the ceiling, and drywall all around. I got a small portable A/C (12,000 BTU, which is just a bit small for 550 sqft), and it doesn't quite cut it, but it brings the internal temps down from 100+ to <80 - quite workable.

SO - I finally got started tonight! Woo!

I got main power wire run (4gauge from battery with ANL 60A fuse 11 inches of wire from batt), I got the head unit wiring done (used a pair of aftermarket/factory harnesses to make a super-short tail I can cut into so I can access wires at the HU without altering factory wiring), installed the rear coaxes (a pair of polk 2.77 ohm coaxials with an external crossover) and installed the midbass in the front doors (basically just made quickie MDF baffles in the factory locations, nothing special.

None of that is really pic-worth...

But then I decided to put a few more hours in and put together the skeleton of the trunk:


So hooray for progress!

What you're seeing is both the top of the box and the trim panel all dummied up. The bottom of the box is an exact duplicate in shape of the hard plastic panel that sits in the bottom of the hatch, and the top will rise 10" from the bottom of the trunk to sit approximately level with the 'hump' and the back end. Then the trim panel pieces will be fiberglassed together and smoothed out to fit exactly out to the sides and will sit atop everything somewhat like what's shown here - but there won't be the gaps between pieces, that'll all be 'glassed. Once it's all completed it'll be sanded and painted in a dark grey.

Now I gotta get up in about 4 hours and get ready for work, and with conversion starting in less than 24 hours, it'll probably be a week before more progress :(

Oh well. I'll post more when I can get to it.

Re: Probably not of interest to most, but - major audio over

Posted: Fri Jul 22, 2011 9:46 pm
by rwherrick
Wow - can I assume you are a professional sound system designer? Or do you just spend all your time reading up on the subject ;-)
My other question is, are you likely to use 300 Watts only when the system is cranked up enough that it would blow you out of the car, or would it use quite a bit of power even at modest volume levels?
I'm very interested in the tradeoff between audio performance and power consumption. I told a Nissan engineer that one of the things I found disappointing about the Leaf was the poor bass response of its audio system, which is the worst of any car I've owned in the last 25 years. I am NOT an audiophile, but it did still not meet my expectations. The engineer told me that putting a "normal" stereo for a car of this price (larger door speakers and a subwoofer on the dash or rear parcel shelf) would significantly reduce the range, which I thought was surprising. If anybody has collected power consumption data from typical car stereos, please share it here!

- Bob

Re: Probably not of interest to most, but - major audio over

Posted: Fri Jul 22, 2011 10:49 pm
by drees
Nice project - FWIW - I would be interested in the pics of the "easy" stuff you did earlier as I'm sure many others would be if you have them. I expect that many will end up replacing door speakers - but a lot fewer will go as far as you are with the rear-sub setup. :)

PS - Look into adding insulation to your garage door - that's likely a major source of heat gain now that you've insulated the rest. And if you do decide to get more AC in there - look for a mini-split - super efficient and not too expensive.

Re: Probably not of interest to most, but - major audio over

Posted: Sat Jul 23, 2011 5:29 am
by defiancecp
Not quite a professional at it - I did stereo installs for a small-town shop in the late 90's, but there I never did anything serious. On my own I've done this kind of thing in most of the cars I own, but I think this is the one I've put the most pre-install design work into; most of the rest I didn't have to worry about power consumption.

95% or so of the additional power consumed is consumed by the amplifier, and at rest the amplifier should consume somewhere around 5% of its max current at idle. So, given that most music is naturally transient, I'd estimate about 20% or so of max current (so if max is 10% total range impact, that would be 2% range impact) is used on average at "relatively loud" (not 'booming') volume with normal music, and "family driving" (loud enough to listen to but still talk over) should put the additional power at something like 10% (so something like 1% range impact). Of course, Start playing the 60hz sine wave crap the bassheads play and that'll go way up, of course (not that I haven't used some sine waves for test/setup purposes, but still).

Honestly, I seriously believe the weight added will be more of an impact to the range than the power. The equipment altogether weighs about 40lbs, and that's not including the enclosure or speaker pods.

But that's OK, since I've lost 40lbs in the past couple months, and plan to keep going (I was at 260 May 14th, now I'm 220, shooting for 180). So I've already gained that efficiency back! :D

As for comparing normal factory high-end stereos, I never really payed attention to what those consumed in power, but I can't imagine how it would have a significant impact on range... I'll monitor my own range closely once everything's in and see if my math holds true in real-world application, but I'd be really surprised if it went significantly above that. And factory systems all get their power out of the main fuse panel, which is limited to 30A, right? So that puts any factory system powered that way at about half what this one will consume, meaning full blast would cut 5% of range, and most of the time a user would never come close to that...

But then again, if they're using worst-case as the basis for their 'power budget', 5% is a significant range impact on a car like this, so I can see where they're coming from.

Anyway, I'll get some pics of the front/rear speakers and any relevant wiring as soon as I get more shop time.

*edited to clarify percentages*

Re: Probably not of interest to most, but - major audio over

Posted: Sat Jul 23, 2011 10:18 am
by LEAFer
Wow ! Congratulations on the weight loss ! :P ( I don't know much about stereo upgrades ... so I can't comment ;) )

Re: Probably not of interest to most, but - major audio over

Posted: Sun Jul 24, 2011 4:19 pm
by BLUEH20
Bet no one will complain about the factory installed predestrain noise maker when you have this system fired up!

Re: Probably not of interest to most, but - major audio over

Posted: Sat Aug 06, 2011 7:19 pm
by defiancecp
Sorry to have near-zero updates for a while, it's been crazy at work and this project has sat as-is for a while. I just finished up fiberglassing the rest of the box, though, and now I'm working on the a-pillar pods (FINALLY). I'm going to try to rough-complete (complete them functionally and shape-wise) the a-pillar pods tomorrow, but I seriously doubt I'll have the time for the cosmetic finish-up. Either way I'll get some pics up tomorrow, and I'll get detailed pics of the tweeters, door speaker area, etc. as requested.

Re: Probably not of interest to most, but - major audio over

Posted: Sun Aug 07, 2011 10:43 am
by defiancecp
New update. Started on the speaker pods. First pulled the a-pillar trim:
then made some speaker mounts:
Then taped up the trim and figured out my speaker mounting position:
then layered on the bottom glass:
flip panels, top glass:
finally put in the speaker mounts and glass the gaps:
and here's the rough shaped panel:
And removing the tape, no damage to the stock panel :)
Yeah, there's some residue from the tape, but nothing that won't come off with soap and a scrub :)

Obviously far from finished. I need to get an angle grinder after them to cut the panels into the shape I want, then rough sand, then body filler, then smooth sand, prime, perfect sand, prime again, then paint. Then they can go in :)

Re: Probably not of interest to most, but - major audio over

Posted: Sun Aug 07, 2011 10:45 am
by defiancecp
btw, sorry I haven't gotten pics of the speaker mounts and stuff yet. The fiberglass staging area I have set up takes up a full bay in the garage, so no room to pull the leaf in until I complete the fiberglass projects (leaf lives in my carport; the garage is separate so it's just more convenient that way). The garage is nice & cool now, so I don't really want to work on the actual car until I can pull it in the garage :)

Re: Probably not of interest to most, but - major audio over

Posted: Sun Aug 07, 2011 11:31 am
by drees
Nice pics - can tell it's going to be great when done!