O, Hai!

[madmat]

Hello again kiddies it's me, the mad one. Today I'd like to talk about car audio, more importantly, yours truly and car audio.

First, let me give you all some background. I kind of fell ass backwards into computers. I never really cared about them, indeed, up until I bought my first PC I never gave a rat's ass about them. The only computers I'd ever been around were either IBM's that ran DOS and just had crap on them for work and C64's. Neither of which impressed me, at all. At that time I had two consuming passions, car audio and going fast.

I started my love of going fast when I was born, most likely, because the first words out of my mouth were "race car". I'm kidding, all babies first words are mama but race car wasn't far behind in my vocabulary. I drew cars on everything, built car models, had every Hotwheel car from their inception, watched every race known to man, started reading Hot-Rod magazine at the age of four and dreamt of nothing less than driving on a track flat out. I never made it to the track. Along the way I bought a used hifi receiver when I was eight. I became enamored with audio shortly thereafter. In my teens (14 or so) I began designing and building my own speakers. I joined an audiophile club and hung out the local uber hifi shop, the owner was also the founder of the club. At meetings we could all bring media and listen to it on a system he'd assemble for the meeting. We had uninterrupted quality time with the state of the audio art equipment of that time.

I moved into car audio when my older friends would get stuff for their cars and we'd install it. Since I was such a gearhead and into audio in general I was a shoe-in to help them tear their cars apart to put in new tunes. When I got my first car I set about making it as fast as possible (got it up to 160mph on a country road) and as loud as possible.

I literally went through dozens of stereos in that car. My last and best setup was a pair of infinite baffle Peerless 8's, a pair of Focal 5.25" mids, a pair of cheap solid state tweeters and a Coustic 120W amp. Added to that was a 12" infinite baffle subwoofer running on an Alphasonik 65W mono subwoofer amp. It sounded quite good. That was in '85.

I went on to more cars, more stereos and in '89 I moved into the pros, I began installing for money. I did that for four years. In '92 I ended up getting screwed by an employer for about $5000. I also got in a bit of a sticky wicket that cost me my motorcycle and ultimately my license. As a result I didn't have a car until '97 and no car audio. In '97 I ended up getting my license back and got a van. I got back into car audio as a direct result.

I kept upgrading vehicles and upgrading my audio systems until I peaked at a 10 speaker 1120W system in a 1988 Firebird. It was loud. Insanely loud. That was when I decided to break down and buy a PC. I bought it with the intent of using it to design speaker enclosures to get even louder.

Something happened though. I ended up tearing the PC down and upgrading it. More ram, more hard drives, better GPU, faster CPU, etc, etc. Before I knew it I gave all my car audio stuff away (except one lone surviving Orion Co230) and started dumping every penny into my PC and devoting all my spare time to being on it. This continued until recently when I bought a new ride. I bought it and found an abandoned Eclipse deck in the trunk.

Naturally I put in the car, this meant it needed new speakers. I replaced them but it still had no bass. This meant I needed a sub/amp. I got that but it still lacked. It's been ongoing ever since.

Now, I'd be more than happy to share what I've been doing since along with all the gory details but I need to know: Does anyone care? Is there any interest? Anyone else want to share? I've discussed doing car audio related articles with Rob and I'd love to but I want to make certain anyone cares. What would you like to see? Any ideas of subjects to cover?

That's about it, thanks for reading and thanks in advance for any input.

 

[Rob Williams]

Thanks for the back-story, Matt. My enthusiasm for audio has been refreshed just by reading it, hah. I am the furthest thing from being an audiophile as I've mentioned in the past, but I do sometimes feel like I want to study up and learn more about the ins and outs. I know good audio when I hear it, but to explain it to someone... I'm stumped. Heck, my inept audio knowledge is partly the reason we have Rory on staff, haha.

I have to ask though... what was your first car? You've told me before, but for some reason I can't remember. Must've been one hell of a build to go 160MPH on a country road... I can just imagine the growl that thing must've made.

I wish I could input more, but I'm even less familiar with car audio. I guess partly the reason is because I don't drive, so when I do end up getting a ride, I'm sure my enthusiasm for it will grow exponentially over time. I'm also interested to 'gage' other's interest in this area... so let's have it, folks.

 

[madmat]

My first car was a1973 Pontiac Grand Prix. I built the stock 6.6 up with an Edelbrock Torker intake topped by an 850CFM ThermoQuad, Crane Blueprint series Ram Air IV regrind, Rhodes lifters and headers. I put Competition Dynamics springs and retainers in and the top end was good for making power to 7000RPM. A rough estimate was about 450HP to the wheels. It'd do 70MPH in 1st, 120 in 2nd and the top speed wasn't ever officially reached, I wasn't brave enough to try past 160.

 

[Merlin]

Ah HA....So that was you over on Moon Station Rd.......I wondered who that could be going that fast
Art and Computers are my deal.
And when I merged them together, well, it was limitless at the thoughts of what could be done.
Even my Art on Computer cases. much less using one to create.
As far as work, for 23 years I built aircraft, now I'm in the entertainment field...lol
I provide entertainment to thousands ( Comcast ).
Lately, I have been taking care of family, my brother is up here from FLA, no work down there. We got him a 99 Mitsubishi Galant for 17 hundred, now we need to change his license over to Ga. It's a delima, not much proof he resides here, as yet.
He has taken care of our Mom for the last twelve years, now she is in a nursing home in FLA. We call every other day and holidays.
Not much of extra money to accomodate my habits of computers right now.
But I have rebuilt a few engines, not content with stock parts, I gave each a little boost, even went to the Dallas Drag strip a few times, Racing is in the blood, Dad used to race and my uncles, R C Hazlitt raced at Dayona back in the 50's, most of this info I gained only after finding my Dad and then going camping, all the stories came out around the late campfire.
Every now and then I go gold panning in the creeks nearby, but nothing like when Dad and I went to Yuba, Ca. The original gold rush area in Californeee.
I don;t think I could go rock climbing like I used to in north Ga, pigeon mtn around the Tenn / Ga line, I'm so out of shape...( ha )

that's my story....Anyone Else ?


Merlin

 

[madmat]

Nope, I never drove much over the speed limit here. I've outgrown that foolishness. It was on March Lane in between Lodi CA and Stockton CA in 1984. I only got the engine up to around 6000RPM doing it but I sustained it long enough to spin all the rod bearings. The engine was basically stock at that time.

 

[Rory Buszka]

My interest in audio began as a teenager in high school. I'd often enjoyed going into stores like Best Buy and Circuit City, and checking out the fascinating variety of speakers and audio systems on display. I naturally gravitated toward the speakers, because they were the most 'mechanical' of the audio system components (except, perhaps, for compact disc and DVD players), and because there was such a wide variety of designs available.

Later, at a Radio Shack that was selling off their inventory of technical and hobbyist books, one in particular stood out to me as I pored over the titles: Advanced Speaker Systems by Ray Alden, a book that detailed the process and considerations for designing and building custom high-fidelity loudspeakers, starting with raw drivers. My first design based on the book's information - a subwoofer - was a flop, but I had made several poor assumptions in my design -- chiefly among them the assumption that a driver that was visually similar to another driver could be substituted for that driver with no ill effects. After shoring up my knowledge and plugging the holes with information from internet resources (appropriate shout-outs given to the Subwoofer DIY Page and DIYAudio.com forums), I attempted another subwoofer using a brawnier driver, having in the process learned to use computer simulation programs (like WinISD), and was considerably more successful. I proceeded to annoy my parents with rattling dishes and glasses in the cupboards downstairs as I enjoyed the best bass I'd ever heard.

Following the success of that early project, I turned my attention toward full-range speaker designs. About that time, Parts Express had acquired overstock inventory from a high-end speaker manufacturer called Definitive Technology (http://www.definitivetech.com/), so I selected four competent-looking 5.25" midbasses (originally from Def Tech's BP8 loudspeaker) and a pair of aluminum-dome tweeters made by the Norwegian manufacturer Seas (from the company's BP30 loudspeaker), and designed a textbook second-order filter network to divide midrange and bass frequencies to the midbass drivers and high frequencies to the tweeter. I built my first pair of medium-density fiberboard boxes (the earlier efforts had been made from 3/4" plywood), and lined them with open-cell foam, installed the drivers and crossovers, and suddenly my ears were opened to a new world of detail and clarity that I hadn't heard from most of the electronics store speakers. (I should note that since then, Best Buy picked up the Athena and Klipsch brands and seems to have dropped KLH, greatly improving what you can find there.)

Since then, I've designed and built two more full-range speaker designs and one more subwoofer, all three designs for a friend of mine, as well as a few experimental designs that have met with varying success, and a super-high-power 500-watt powered subwoofer for my own use, using a driver I won in a contest to redesign the logo for a small-batch driver maker, AE Speakers (http://www.aespeakers.com/). I've got several other designs waiting to be built, and countless sketches, as well as drivers on hand to build six more designs. And, of course, my interest in audio and loudspeaker systems shows no signs of waning.

It was audio that originally brought me to Techgage. PC hardware technology had been a fascination for me for even longer than I'd been an audio enthusiast, and I had already built my first and second PCs. I'd seen Altec Lansing's FX4021 PC speaker system in the local Best Buy, and was impressed by the quality of the bass it produced -- far above what was available in its price category. So as soon as I arrived at home, I hopped online to see what reviewers were saying about the product, and I happend upon Techgage's review, which contained some technical inaccuracies. I hopped into the Techgage forum to weigh in, and then it occurred to me that as a college student, I might be able to make the time to become a hardware reviewer as well, and get the chance to describe products' technical advantages in review articles. Rob obliged, and the rest is history.

 

[madmat]

You'll like what I've just purchased, Rory. Let me introduce you to the DMX/RE hybrid I'm going to be putting in my trunk, all 15" and 50lbs of it.

It's not a lot to look at from the front, the simple parabolic concave poly dustcap covers the cone up to the 1.5" rubber based foam surround. The cone/surround/spider are all RE pieces, it looks to be from an SE15.

The voicecoil is not an RE part from what I'm given to understand. It was made by the guy that made the recone. It's a dual 2 ohm that's super long to accommodate the huge motor on this beast. I'll get into that later though. It's an overhung design that should provide about 1.5" of one way excursion. The original DMX was designed for 30mm one way excursion but it was also a light cone (CF cone, CF dustcap) with a 40hz FS. The SE15 has a FS of 22hz.

Enough about the FS, let's move on to why I know it's not a voicecoil from an SE, it's flatwound and the SE versions are round wound. Not to say it's not based on an RE motor, the guy that reconed it seems to be associated with them so it could be wound on the same former as the original XXX which had a very similar motor to the DMX.

Since I keep blathering about the motor structure, let's look at it. It's a double slug motor (for the uninitiated out there that means it has two magnets) with twin 136oz slugs. The VC is 3" and the top plate is about 30mm thick. The VC overhangs the top plate by close to an inch and the motor will make motive force until the top of the voicecoil is halfway down the gap which is 30MM the same height as the top plate.

The spider is a fairly soft 9" diameter progressive roll unit, I dunno what material RE uses but it looks like the spider on my RE12. Except for one minor detail that is...

It has a clamp holding it down rather than adhesive. If you look at the tinsel leads, there's a felt pad between them on the side of the cone. It's to prevent noise from tinsel slap on long excursions. I'm considering breaking the sub down and stitching them to the spider though, I've seen it done on other subs and it's pretty sweet. I need to find out if they've got enough slack to do it first.

The sub was originally a quad core sub but I'm also considering doing away with the fiberglass mount for the terminals and moving them to the locations on the basket. Less stuff to worry about rattling loose.

You can also see the screws securing the clamp for the surround (it's the plastic ring where the gasket would traditionally go) and the clamp for the spider. Sadly, if this wasn't a modular sub, you could put a 10" spider on it although a 9" is still good for 30mm+ one way linear excursion.

And here's the money shot, the rear of the sub. The motor is removable, not glued and screwed and might possibly be removable without pulling the cone, I haven't looked but if it can be I might buy a couple more baskets (one 12" and one 15") and a couple of recones for them just to have more options. I think a 12" sub with a 35lb motor would be impressive, hell I'd like to try that motor on a 10" sub.

As to my other plans, my SE12 is a D4 sub, I'm seriously considering replacing the stock Logitech 8" with it and just graft the amp from the Logitech's to the enclosure it's currently in. It should sound awesome and not be prone to blowing unlike the stock Logitech unit. The SE12 handles 1200W (daily) so an unclipped 120W signal should be little problem for it.

 

[Merlin]

Holy @!*$ Cow
I could probably hear the low tones from here, with those

Merlin

 

[Rory Buszka]

Nifty.

By nearly all standards, that looks like an impressive sub driver, Madmat. The paint job on that nice 12-spoke MTX-style frame isn't quite as clean as I'm used to seeing near the spider vents, but that could just be the reflection from the flash. I'm assuming that SQ will be the goal, not just raw SPL, so I'd bet that a low-Qtc sealed alignment is what you've got planned for the car, while the enclosure to replace your Logitech sub will be a vented one.

It's such a shame that my own subwoofer is just taking up space in my grandparents' garage until I can find a better day job around Indianapolis (though I was just laid off from the job in Chicago, so that adds an element of urgency) and can rent a place of my own. I suppose it's just as well - I don't suppose my neighbors would appreciate that kind of bass as much as I do, so my ability to enjoy the sub would be limited.

 

[madmat]

It's not painted, it's powdercoated. You're seeing dust on the finish. Yes, my goal is indeed SQ and no, no sealed enclosure for me, I'm going with infinite baffle. With a 35 cu-ft enclosure the sub will do 125db at 5hz up at 800W. The basket isn't an MTX piece, it's used by dozens of MFG's. My RE SE12 is built on the same basket, their SX line uses it as does the MT SPL woofer and the older XXX. I've seen hundreds of woofers built on it. It's more popular than the older 4 spoke designs.

I can hardly wait to get it all installed.

 

[madmat]

http://www.youtube.com/watch?v=3gPzpsgr87s

A little free-air excursion testing. ~324W swept sine wave from 20hz-120hz.

 

[Rory Buszka]

Right, but the basket itself originated with MTX's original "Thunder" line of subs, and is referred to as the "MTX"-style basket by woofer makers. The 4-spoke basket is referred to as the "Venezuela" basket, and its 15" and 18" versions have six spokes instead of four.

The Venezuela basket doesn't see as much usage these days on the real high-powered subs as the MTX basket, since the MTX basket has better provisions for under-spider venting. The only other basket style that's common out there is the TC Sounds ultra-high-excursion basket, which accommodates 10" spiders on the 10" version and 12" spiders on the 12" and larger frames, and is recognizable by its enormous windows underneath the spider, showing that there's a tremendous amount of travel before the spider bottoms out on the top plate. TC Sounds also has another custom-tooled basket, but it didn't see nearly as wide use -- some TC Sounds woofers and Soundsplinter woofers used it.

That's certainly a nice driver there, though. I'll dig up some photos of my own home-theater sub and post them.

 

[Rory Buszka]

Ok, time for some pictures.

http://www.deathspawner.net/friends/rory/www/images/sub_grilles_on.JPG - This is the subwoofer I used through my latter four years of college. I built it using a driver that I won in a contest to redesign the logo for the company that sold it -- AE Speakers. Much of this sub's bulk is actually the 1.5" on each side that I allowed behind the grilles to protect the driver and two passive radiators. The sub weighed about 140 pounds when fully-loaded with the driver, passive radiators, and amplifier.

http://www.deathspawner.net/friends/rory/www/images/sub_driver_pr.JPG - Here's the subwoofer with two of the grilles removed. This was the first project I ever did with grilles. In addition, there's quite a bit of construction dust still around, as this photo was taken as soon as the sub was brought home for the first time. The driver is an AE Speakers AV12-MkII, with 23mm of one-way excursion and a resonant frequency of 22 Hz, driven by a 500-watt plate amplifier bolted onto the back. The enclosure is 3 cubic feet, and tuned to 19 Hz using a pair of 15" passive radiators with an inch of one-way mechanical excursion each, and massed to 1400 grams.

http://www.deathspawner.net/friends/rory/www/images/dorm_front.jpg - the front stage of my 'dorm theater' at the end of the 2007 fall semester. This is one of the better photos of my DIY main speakers, built in 2002 (currently disassembled), which use a pair of 5.25" woofers with poly cones, butyl rubber surrounds and dust caps, and cast magnesium frames (originally made for the Definitive Technology BP8 loudspeaker) and a Norwegian-made Seas H537 aluminum-dome tweeter per speaker, crossed over at 2400 Hz with a textbook second-order crossover network. The only thing I neglected in the design of these speakers was a notch filter to control a sizable 4dB peak in the woofers' response at about 3500 Hz. Feel free to rib me about the old TV and the lack of a center channel speaker.

These are photos of early projects, so the quality of the construction isn't quite what I'd be capable of today. Hopefully I'll have some new photos before too long.

 

[madmat]

Cool. Sorry I missed this yesterday, my internet was down for most of the day. I bought some Polk MMC650 coaxials for my doors as they'll fit in there without modification. They run outboard crossovers and I'm using my MM6 crossovers rather than the factory set as the MM6 set has mylar caps and tweeter attenuation settings as well as the option to run the mid fullrange. I've hooked them to my P400-2 and put them in a ghetto baffle to get an idea of how they sound and they're pretty nice, far better than my Infinity coaxials. I'm looking forward to getting it all installed finally.