Birch ceiling? In a car? I've never seen that before... This build could get interesting, can't wait to see more- nice!

 

Subscribed!
I like the way of thinkin when it comes to the birch in the celing. And the Mark Audio fullrange looks amazing!

Are you gonna use the OEM Headunit? If yes, are gonna have a DSP hooked up to it?
Any ideas for amplifires?

 

OEM headunit is the plan for now (and the expected future) - it has all the functionality I really want (usb in, steering wheel remote, etc..). I know a processor will eventually make its way into the car, but only after I get a substantial portion of the build finished. I'm currently toying with the idea of using a carputer for my processor, but am yet undecided.

The amp I'm thinking of running is a Memphis Big Belle. Though I'll see if the deal goes through (local used sale), otherwise I'm leaning toward ARC Audio suff if I can afford it.

 

Ok.
How is the prices in the US for like DLS, Mosconi, Sinfoni or McIntosh? Compard to Arc or Memphis?
Read some test of Arc Audio amps, compard to european amps. And almost all euro-amps beat them in terms of depth and musical preformance.

Have you looked on B2 Audio Quattro? Great sounding amp, for a reasonable price.

 

Hmm, not sure what any of those amps sell for in Canada, but I also can't find a dealer for them here and am not really interested in importing heavy electronics, paying the excess taxes and import duties, etc...
Does anyone know of a great mobile audio dealer in Canada?

Also, you mentioned that those Alpairs look sweet - I just wanted to go on record stating that if I had a couple hundred bucks more I would have different speakers in my hands right now. CSS just put out a pair that work amazing together - a very wide range mid-bass and a beautiful silk dome tweeter that both run the XBL2 motor technology for low distortion. I listened to the pair when I visited. Not to take things away from the alpairs though - they are still sweet.

 

How did you bend the birch to match the contour of your roofline?

 

Small pannels glued together to custom fit the gentle slopes and curves. I imagine a single piece would be a serious pain to construct and install.

On another note, I just bought a Memphis Belle amp that should be able to power the whole system.

 

This update is merely a hardware/planning update, I've yet to do much more in the way of install or fabrication - bad weather outside is preventing it, but in the coming days I'm itching to get my roof finished - so now I just plan.

First step was to check what the output voltage of my factory headunit is as this is a piece I don't plan on replacing any time soon (too many nice features, plus the added security benefit of having OEM looks). I pulled out the HU and reffered to the manual on the electrical system, plugged in my multimeter and turned the volume up. The most I registered on the multimeter was just over 4V peaks in an excessively loud sound test. You'll notice on the diagram that there's no sub-out on my HU - this is a tricky pickle I need to work around (more on my stereo-to-mono box design below).

I did decide on an amp. It was a local used Memphis ST-1300D (or Big Belle as it's often called). Very pleased with the look, specs, and deal I got on this one. 5 channels total, four@75W, one@300W - THD>0.03% S/N<92db This amp will take care of the whole system, two channels for the Alpair full range drivers, two channels for my rear-fill, and one sub channel with built in LPF and sub-sonic HPF - problem is that it's a mono input for that channel.

(keys in the pic for scale)

I was cleaning the chrome heatsink, so I took the guts out and washed the heatsink, so for anyone interested in what the amp guts look like:

I plan on mounting this beast in the trunk/boot in the shelf just above the spare tire. Since this area has no air flow (as it's covered by the floor of the trunk) I picked up two quiet 12VDC fans to push air through the cavity - I plan on putting slotted vents on either side of the amp to allow this air flow.

The only piece (other than wiring and box building) that's required is a means of hooking the sub into the system. My current plan is to design (or get someone else to help me design) a proper stereo-to-mono sum box. A Y-cable is no good as if a drum hits on the far left, the signal will travel through all points on the Y including a path back toward the right out on the head unit. A single channel input (i.e. just using the left channel output) is no good since I need to split off the signal from the four outputs that are all being used - this will create a 6db (or half power) reduction in the channel I split off from. In the end I realize I need to get some circutry made, and since a proper rear-fill centre removal and time delay is required anyway, why not plan to put it all in one tidy custom box?

I just so happened to have a sweet looking box that likely has enough room, and some excellent feeling potentiometers on the front - my Altec Lansing NT1201-8a crossover (from a woofer I have in storage and don't plan to use anytime soon). I figure there's enough free space in there to leave the somewhat valuable Altec circutry in place but also hide my own custom board on the opposite interior wall. If anyone knows a good audio electrical guy that enjoys projects, send him my way

While I was at the electronics stores planning some of this stuff out, I came across this sweet looking retro fader control (and I mean the box was even unopened from the 60's sorta retro). I already have a fader control in the HU, but I'm sure I can use this plate for some delay control.

Also, I got the brilliant notion that as I'm planning to soundproof the firewall, I'll need to take the dash apart. During that time it'd be really nice to add in some VU meters in my instrument cluster - there's some space for them just below the tachometer and spedometer. I'll need to back-light them some how and create a nice looking way of mounting them there, but I love VU meters, they're sexy even when they're tiny.

 

Oh, and here's a better pic of the exterior of the car. Just took this on a recent trip.

 

Subscribed, looks like an interesting build! I found a bridging module tonight when I was going through some boxes, it is an Audiobahn one, but it should work for your setup. PM me and I will get it to you, if you want.

R

 

i just found out that it is now posible to get a coat put on beneath the car to prevent rust, in adition they can also put on an sound deadening layer aswell.. maybe an option for not pulling out seats and carpet?

 

I'd rather pull seats and carpet than mufflers and fuel/brake lines before having the underside sprayed. Might be different if I was doing a ground up build, tho i'd probably do both.

The birch on the ceiling idea intrigues me.

Jay

 

Quick update: I've gotten my headliner back in the car now. Upholstered after stage 1 of design. I'm now calling this stage 1 because it was about a 4/10 on the success scale. This post is going to concentrate mostly on the issues I had along this stage of the process. I'm already working on solutions because I love how it sounds.

I finished the diffusion in the headliner, finished the absorption roof, reupholstered the headliner, and re-installed.

The diffusion pattern has three binary sections of various sizes, and three free-hand MLS-style diffusers (yes, I know free-hand diffusers are a silly idea but I needed to open the space up to the absorption more to prevent causing a helmholtz resonation.

When I went to apply the fabric that I originally picked out, I noticed that the fiberglass bumps, cracks, frayed-ends, diffusion holes, etc... all showed through as texture on the very stretchy (think swimsuit) material. It had been the most breathable, and looked very 'stock' for the car so I had purchased it without this consideration in mind. I did quickly run to the fabric store and get a very thin stretchy black layer that I thought might fix the issue, but in the end it did essentially nothing but waste money. I'm thinking a dark color of a less stretchy fabric will hide these issues better. I'm toying with the concept of lengthwise pinstripes. This stretchy fabric also had a handful of glue bleed-through points where the fabric got wet with the glue during the application process and is noticeably discolored though most of these are hidden by complex curves and shadows around the sun visors and passenger handles.

The birch suspended interior was finished off and I glued some 1" thick slabs of roxul fiberglass insulation onto it. This is acoustic absorbent that hopefully won't see moisture sucked into it over the years (I may end up installing a dehumidifier in the car if it becomes an issue - I'll probably be getting a deep-cycle battery eventually anyways). My neighbour commented at this stage as he stuck his head in the open car "It'll be like listening to music in a giant earmuff!"

In the end, after installing back into the car the centre large diffuser obviously took too much structure out of the headliner. The middle of the headliner buckled and is now 'installed' but collapsing above the rear middle passenger (it's stable and could probably remain there for a number of years if I didn't care how it looked - but I do).

The positive is that the sound in the car (keep in mind I'm still using 100% stock equipment on this install - the aftermarket stuff has yet to be put in) is absolutely miles above what it used to sound like. There is a widening of the soundstage by about 6" on either side of the front door windows and the overall area of the interior sounds more spacious. I feel like there's a crispness in the upper-mid range (say 6KHz-ish) that certainly had never been there before. No measurements have been taken, so this could be a placebo, but it's my ears that I care most about on this build.

I plan on taking the headliner out, re-enforcing the structure with some steel mesh bent into shape, adding some thin foam to the underside to smooth things out, and probably choose a different fabric.

 

Try passive de-humifying...works great for me.

I always have a bunch of packets, stuffed under my seats (I collect them at work, before they get thrown out in the trash)

http://www.silicagelpackets.com/sil...ckets.com/silica-gel-packets/silica-gel-packets-cotton-tyvek-sachets-dry-packs/

 

Very interesting build. I am anxious to see more.

 

I picked up some clear flexible 1/4" vinyl tubing at the hardware store and ran it through my door weather stripping. I picked this idea up from UNBROKEN on diymobileaudio.com and thought it would be a great way to increase the STL (sound transmission loss) at a clear weak point in the car. The door clasp now pops open when opened, but that's a minor issue that I expect will slowly disappear with time (as the tubing gets more squished into place). Update: Sure enough, a week or so after install essentially all effects (other than the reduced sound transmission) have disappeared - though if the door is closed too lightly it does not fully close (as is common amongst most cars, just slightly more so).

The car comes with a false floor storage area above the spare wheel already and my amp fits nicely into the lower section, leaving space for a processor and carputer. It also happens to fit my cooling fans quite nicely. The only problem is that it's made of moulded styrofoam and an amp that's bolted into styrofoam can easily be ripped out. So I need to add in a layer of wood, and probably some means of securing it to the vehicle itself.

I came up with a design where I upholster the styrofoam in some black cloth I have lying around, then put a birch ply floor in the insert, then a chrome trim around the birch to match my chrome amp. I'll figure out how to secure it to the body of the car later, but probably won't post it here for the world to see due to obvious security reasons.

I took some time to sound deaden the hatch. I also found large cavities of space in the rear corners of the car that would work perfect for bass traps (yes I plan on soaking up the excess bass that cabin gain gives me) or for a sub enclosure if the centre console idea turns out to be a bust/too complex/etc...

I also happened upon some heat and noise reduction paint on sale at the local tool store. Made by Al's Liner, which makes products for truck bed liners and is designed for hot-rod applications for firewalls - similar to the Second Skin Spectrum paint that others might be familiar with. So as I was changing the tires from winter back to summer, I lathered a good coat on each wheel well interior. It's tough to judge the effectiveness as summer tires are normally quieter than the winter tires, but yeah there was a reduction overall in noise transmission. I'll take a look later to see if I can reach my firewall with this paint - though maybe I can tackle it from the interior when I go to put in mass loaded vinyl.

Oh, and I fixed the headliner by putting some 1/4" steel gardening mesh on the upper-side to re-reinforce the weakened structure, some vinyl-coated polyester mesh on the lower-side to smooth out the speed holes, and finally re-upholstered with thicker cotton to hide more of the modifications. It doesn't look perfect, but I can live with it for the life of the vehicle. Next time I won't destructively edit any pieces of the original vehicle - lesson learned. Too much work for what that was worth. I'll post a pic of it installed when I can.

 

Wow.... some really interesting stuff here!! Like what your testing/experimenting with on this build. Keep up the good work.

 

Thanks for the invite. Lol
Wood roof treatment...would've never considered that. Great job!
Look forward to your results.

 

There are essentially two simple ways to combine the L and R signals and do it without using a "Y adaptor" which, as you know, is a passive device designed exclusively for splitting an RCA signal and not combining two different signals into a common cable. Bravo to you for understanding that it's not the way to do it. Okay, you can do it easily by using a summing transformer. I recommend the Edcor SM2. You'd simply use a Y adapter on the front L and R cables, sending one lead into the amplifier, and the other into the summing transformer. The transformer's mono output would go into the amplifier's mono input. Simple.

If you were looking to construct a summing circuit, you could do it by very easily by wiring (1) 1/8w 10k-ohm resistor from the "+" lead of each the L and R signals to the "+" lead on a single RCA cable. For maximum cleanliness in the wiring, you could construct a project box with a L and R input jack and a L, R and C (combined) output.

I hope this helps.

--david

 

Loving the originality and thought processes going into this install! Some truly passionate work there my friend!
Sub'd for sure!

 

very cool... cant wait to see more.

 

Sub'ed

 

Have got the Australian version of this car- the I30. Keen to watch your progress

 

so whats your take on the modifications and how they have effected the noise level and standing waves?

 

Well I seriously regret not taking before/after recordings to analyze my changes, because the roof did take a few months worth of my part time labour. By the time it was installed I had come to know the new sound fairly well and it's tough to describe entirely objectively.

I think I can sum the changes into two effects:
1) The wood roof's reinforcement of the cabin gain phenomenon. The stock speakers of my Elantra are now easily sounding beefy and strong in the low frequency. They still sound muddy, so I'm still going ahead with the overall upgrade, but I'm very pleased right now with the acoustic benefit of the wood roof. It also significantly quiets the cabin from external noise.
2) The diffusion panel design added a listener envelopment to the space. I'm totally unsure if it has broken up modal standing waves in my midbass region, as I have no measurements to confirm or deny this. I do quite enjoy the fullness of the cabin's acoustics right now - though I'm not done yet

I do have a significant update or two to post, but no time just yet. Sorry to keep everyone waiting.

Have got the Australian version of this car- the I30. Keen to watch your progress

Is yours an i30cw or a regular i30? The Elantra Touring is an i30cw in all other markets. Have you visited i30ownersclub.com yet?

 

Cant wait to see how this turns out.


love the amp choice. I just picked up a few old school memphis amps from here that i really have no use for. I just remember how much i loved them back in the day and coudnt pass em up.

 

I've had a bit of time since my last update to putter away on this project. Unfortunately I'm still no where near completion, but I am making great progress and headway.

First things first, I got a little bit more gear. To join the setup is the Rockford Fosgate 3sixty.2 signal processor. For those unfamiliar, this processor will allow me to time-delay and EQ each channel individually as well as auto-correct the factory stereo's built-in EQ curve.

I also got a hand-held Sony PDA for $30 off craigslist so that I can control the 3sixty.2 through bluetooth. (the software required a Palm OS or a Windows mobile OS - and I trust microsoft about as far as I can comfortably spit a dead rat, so palm it is) It's nice, but has no real functions that I need/want other than controlling the 3sixty.2

I've been working hard on my amp rack. It's entirely upholstered and has the wood floor cut, sanded and stained. I wired up all that I could while it was outside of the vehicle. This includes a relay for the turn-on circuit, a on/off switch for the fans (they're on the turn-on circuit, but if I want them off for judging the switch allows that), and proper fusing. All of the connections are soldered on with heat shrink tubing. Now all that's left is final installation into the vehicle.

I've also mounted the bass/volume knob from the 3sixty.2 in one of my blank instrument panels just to the lower left of the steering wheel and ran the wires to the back.

Speaking of wires, I soldered together a wiring harness for my OEM headunit. It allows me to easily switch between the stock wiring and the aftermarket wiring. It also allows me to lift the turn-on wire without any cutting or splicing of the OEM wiring. Quite pleased with how it turned out, but am having a bit of troubles getting it to fit nicely in the dash's cavities with all the wires plugged in. Another afternoon will need to be spent sorting that out.

I also put the grounding wire in the hatch. Chose to use one of the child-seat anchor screws that I never plan on using (my daughter's child seat is always in the middle of the back seat, so the ones off to the side can go).

Finally, the subwoofer enclosure has progressed significantly. I have decided to abandon (at least for now) the notion of a centre console transmission line or tapped horn due to the level of modification to the car that it would entail (says the man who installed a wood roof ). There's also key safety equipment like the airbag deployment brain (I don't know the proper name for it) hiding in the centre console, that I'd rather not put under heavy vibration stress. Maybe one day I'll build the centre console enclosure, but that'll be a few years away. As a second/backup plan I chose to put the sub in a sealed stealth enclosure in the rear passenger hatch area. There's some space behind the interior body panels there that I plan on using. I'll post another update that details the sub enclosure, but for now, here's some mounting rings for my three drivers.