**New Tech Article*** <<>>

[E30Adam]

Kindly written for the zone by Paul Lacey (placey).

A very big thanks from the zone team, great article mate.

http://www.e30zone.co.uk/modules.php?na ... echice.htm

[Kedge]

Great Article there mate, loads of info, should answer most peoples questions aswell.

[nwmlarge]

i found it an excllent article and very well paced

[Simon]

Well done Paul, top man!

[billgatese30]

absolutly brilliant mate.

[johnono]

well funny aswell ! now i want to go out and rip out those pansy rear speakers and fit some CONESSSSS!!

[Omi]

Placey, great article... Can I pick your brains on my intended install?

[placey]

thanks everyone i enjoyed writing it. i made myself laugh a few times and believe it or not had to leave some stuff out as i thought i was going on a bit!

omi - go for it. i'm not saying i'm the world's expert on ice but i'll always try and help whereever i can.

paul

[tbmw]

have just read the article, very wel written and a good read

[Omi]

OK... I'm currently running 6.5" JBL GTO 2-ways on the parcel shelf, tweeters angled into the cabin, powered by a JBL Decade 2-ch amp... Clarion 5.5" flush-fit 2 ways with the drivers in the kicks and tweeters wedged into the heater vents on the dash. (No laughing)

I'm looking at upgrading to:

Alpine CD9812-RB MP3 h/u
JBL Decade amp (bridged) running a 10" JL Audio 4-ohm 100w SVC sub in a sealed enclosure in the boot, facing an open ski-hatch (no arm rest though)
Genesis Profile OR ST60 OR SM60 2-channel amp running a pair of either Genesis Audiophile or Dynaudio 6.5" drivers positioned in the open area of the door-card on a flat baffle, or a build into the pocket area with an angled baffle directing the speaker towards the opposite front window/seat. Tweeters on the inside panel of the wing mirror, angled across.
JBL GTOs can stay in the parcel shelf, on the rear channel of the h/u internal amp.

What do you think?

[placey]

omi

it'll work quite nicely i guess. a lot depends on how carefully you install it all.

i can't remember from memory whether the 9812 has 3 4v pre-outs or just 4v for the sub. 4v pre-outs are excellent and worth going a bit of axtra money for all 3 if you can. alpine 4v pre-outs are green cables so it's easy to tell. don't rely on the written specs - they are worded carefully to sound like all 3 are 4v when sometimes they are not.

fronts - you won't regret a build it'll sound better, you can get the speakers a lot closer to on-axis. try the tweets in different places before finally mounting them - you'll be surprised at the difference.

i don't think you'll ever hear the rears running from your head unit. go for a 4 channel amp for the main speakers if at all possible.

paul

[Ziggy]

Great article! Couple of quick questions if you have a moment though...

My car (being ancient) doesn't appear to have anywhere to cut out for the ski hatch, although I do have a later interior with a centre arm rest... Dya reckon I can still chop a hole in it? I've got a 12" Kenwood sub & amp in a sealed enclosure in the boot if you didn't remember...

Also, I've been considering getting an amp for my front components for a while - they're nothing fancy though, just Alpine 5 1/4s & tweets (think they were about Ԛ£70) so I just thought I'd check you still recommended it!... I'll make some mdf rings for em too as it sounds well worth it! Another difference on mine, is that the factory speakers were fitted with their own grills rather than the BMW covers, so there's no need to modify anything there Though when I get round to putting them in the back & getting some 6's in the front, I'll have to fill the hole with something!

Cheers

Jon


p.s: That item you sold me at the meet, worked fine; I'll add you to the list of good sellers ;)

[Omi]

Paul, the rears won't be used unless I've got passengers who want to listen too... - I'm more interested in a good image and soundstage where I'm sitting.

In your experience, do you think I'd be better mounting the 6.5" drivers low in the door with the tweets co-located, or higher in the doors to raise the soundstage with the tweets tidily in the mirror backs?

I'm thinking the JL Audio sub will be fairly competent with a solid 100w/4-ohm supply from my JBL amp, especially in a sealed enclosure, so I can set crossovers reasonably high, meaning the drivers are going to be handling less low-end and would therefore be better-off higher up?

Or if the sub would be a bit more stressed this way and I'm going for decent components driven by a Genesis, I can sit them a lot lower and have the drivers handle a lot more frequency.

This head unit definately has 3 Pre-outs, not dead cert about the 4v but I'll check... It has the advantage of sub level control and i think it can adjust crossover too... Will have to check.

[placey]

ziggy

cheers - glad it worked. i must add your name too for those articles you helped me out with.

from memory i think the rear of the rear seat has two strengthening ribs that cross in a big x shape - so long as these are not cut you should be ok to chop a 12" cone size hole in there. if in doubt than fold up some extra strengthening from a sheet of steel and weld or bolt it around where you intend to cut before making any holes. This is what i have done above my sub box as i cut straight through the ribs on the rear deck, thus giving back any strength that may be lost. Alternatively cut several smaller holes for the sound to come through. As for the amp yes go for it. any external amp is far better than a head unit powered setup. amplifying the fronts is a load of cabling work but excellent when done and there for future upgrades. i ran the budget alpine components (Ԛ£50, 'custom range' they called them) a few years back off the back of a rather large v12 amp and they sang really well. made me question why anyone ever payed any more at the time....

omi

did you get the m-tech 1 skirts ok in the end?

rears - any cones that are in the vicinity of music but not powered will vibrate in sympathy - effectively absorbing the sound. that's why when you go into a decent home hi-fi shop their demo room only has one set of speakers in it. be wary of fitting drivers that won't be used. as with all these differences we're only talking degrees here but they all add up to make the whole.

as for front locations it really is down to the speakers you choose and your tastes. do you recall the line 'any install is to a greater or lesser degree, an experiment' ?? aesthetics and practicality also come into your equation.

personally i think that lower down looks more 'factory', but it does get in the way of gloveboxes, feet and seat adjustments unless carefully designed. there is a good argument for higher up as it's closer to ear level and easier to get on-axis. tweeters are odd things - some sound great right next to their mid cousins, some sound better far away.

the height of driver mounting shouldn't affect the frequencies you ask each set of drivers to reproduce. in practice the more solidly you install the mids and the more air you can give them to work with the lower and louder they'll go before distorting, thus freeing the sub for bass and sub-bass duties. once all and 'run in' in you can tweak crossover levels to suit.

paul

[Ziggy]

Cheers Paul

I'll start looking for an amp now then!

Here's a picture of the rear seat; not quite sure what to do with it tbh!



Jon

[placey]

hmmm my either my memory failed me regarding the design or the design changed on the facelift cars. anyhow - i'd be very inclined to strengthen that around any proposed cuts. that's what all those ribs are for - else the panel would just be a flat piece of sheet steel.

paul

[Ziggy]

I'm sure they must have changed to let people fit the ski hatch...

Might just go for some smaller holes in the non - ribbed bits? I could cover the bit behind the armrest with some acoustic carpet anyway so it wouldn't matter how it looked...
Not really so keen on getting the welder out, cos it's a bit awkward to get to, & my welding's rubbish anyway!
Had thought I could vent through the top of the box to the parcel shelf... but I've never designed a vented box before! Why's nothing simple?!

Cheers

Jon

[placey]

jon

had a good think about the design of that panel last night and remembered that the facelift cars have the two strengthening ribs but they are parallel upwards and not crossed as i said. yours being pre-facelift must be a different design.

essentially you need to remove some of the metal without compromising its overall strength. i saw an article years ago on how to make those ribs and used this method for mine - cut a piece of board to the desired size of rib, cut the board it came from out slightly and place them either side of your flat steel - then press the outer board down evenly - a press is ideal but a bigger board and decent hammer work well enough. using this method you could make up strengthening ribs to fit around any cut and bolt it in securely. helpful?

paul

[Kedge]

Just a quick one for you placey, will running my sub open air like in the pic work better than it just being in a ported box in the boot with the Ski hatch cut out.

My Sub is a Alpine Type R 12" SWR-1241D running of a 1000w 2channel Kenwood amp, if this helps.

[placey]

kedge

if you like the current sound then leave it be.

the amp looks small - too small to ever give 1000watts. therefore the sub has to make the most of the power it's got to work with. if placed in a box it's possible to tune the box to a specific frequency - this will give the sub every bit of help possible. your local dealer should be able to advise you on box and port sizes, alternatively alpine sell ready made enclosures for their subs. if you're cheeky you could measure one of their boxes carefully and then make your own design specific for your boot. taking out the ski hatch means the sound doesn't have to force its way through the metal of the seat back - making a big difference.

also how much sound deadening did you apply to the panel that your install is attached to? i'd deaden both sides of it if it were mine and do your ally plate too - that sub will vibrate hard and shift a lot of air as sound waves rather than panel shakes!!

suggestion - if you fix some battens to your chequer plate and then board over them (leaving windows to show off your amps) you could hide all your cabling. hinge it at the bottom for if you ever need to get to any of it. if you can find another boot carpet in a scrappy you can then trim it to match the rest of the boot.

paul

[Kedge]

That isn't my install, thats just a pic of www.e30.de i was using as an idea.
This is the sub and amp i am using.


At the moment i'm not getting anywhere near as much bass into the car as i should, that why i was thinking of putting the sub up on the seat backs, but would it make any difference? Should i be ok running the sub open air, i imagine it's pretty much the same as being in a ported box anyway?
I will sound deaden the seat backs and the board with some dynamat i have lying around and then carpet the board.

[placey]

it will be louder in a purpose designed ported box - simply beause the amount of air behind the cone can be optimised. it's all to do with the timing of the sound wave from behind the cone going up through the port so that it adds to the sound wave from the front - effectively doubling the volume - i used to know all about this but can't recall a lot of it now. if you run it infinite baffle (free air) and firing into the cabin then to optimise quality and volume it's important to seal the front of the driver from the rear. this will involve high density foam and/or fibreglass work. check out the alpine enclosures in your local dealer for size and fit - it will tell you a lot of what you need to know.

paul

[Ziggy]

Cheers Paul, missed your reply somehow!

Definately very useful Now I've just got to get round to it!

[Kedge]

Cheers dude.

Plenty to think about. Have my doubts about how well my box actually helps my sub as i isn't designed specifically for a certain sub so i don't know whether that makes any difference, I'll check the specs and see what i can come up with.

[CiLK_WuRM]

Great article, well done that man.

[johnono]

80 CM!



sick sick sick