Scirocco Register

I've had a pair of JBLs in the front since I got the car on the road (2 or 3 years ago) ... I've never liked them, but since getting a new sub, I've found them less than useless.
So I had a look to see why.
Turns out fitting them in the dark in my Dad's garage may not have been the smartest move... Made sense at the time though - it was warm, dry, the original speakers were still in, so I popped the grilles off, unscrewed standard speakers, disconnected, plonked shiny new JBLs in. Job done. (after the well documented removal of the spacer rings)

This morning, Iwhipped the grille off in daylight, and for the first time noticed the MAHOOSIVE gap between the speaker basket and the surround.

I know it's not screwed in in the pic, but it's in the position where it sits when screwed in... and that's a 4mm drill wedged in!

So, that'll explain the lack of bass then; phase cancellation.

So I made a couple of these:


Not the most elegant - Just a lash-up in 6mm MDF to see what it sounded like.

Better... but there's then this gap (where the pencil is):


Next plan is to chop another bit of MDF to fit that gap, then glue on.

Updates to follow...

oh, with the speaker in, you see the point of the MDF:

It still needs the corners radiusing, but basic wedge's done:

And then I notice VW's useful vent. (between door card and speaker pod - below my efforts)

Why, why, why would they do that?
Easy life solution is to fill that with silicone. Just as a means of getting it air tight.
I'll do that before I put it back in the car.

fonzooorooo wrote:And then I notice VW's useful vent. (between door card and speaker pod - below my efforts) Why, why, why would they do that?

to allow airflow thru the door to prevent condensation and rusting.

Nate wrote:

fonzooorooo wrote:And then I notice VW's useful vent. (between door card and speaker pod - below my efforts) Why, why, why would they do that?

to allow airflow thru the door to prevent condensation and rusting.

But it's inside the membrane, and effectively only ventilates the speaker pod itself. The only metal in there is the basket of the speaker. The drain holes and ill fitting window rubbers take care of ventilating the door cavity. Or am I missing something?

Progress:
I've now got both front speakers back in the car, sat in their MDF baffles. It's better. Lots better. Before, you could hear the speaker working, but the amount of bass cancellation was incredible. Also, with the new baffles, I can lower the crossover point significantly, as the driver is now supported by the air, hence lower excursion. Success.

If the baffles were made in steel or ally sheet, the thickness could be reduced enough that the standard grilles would fit back on.

What I still don't like though, is the "shouty" quality that the 4x6"s seem to have. Admittedly, they now have a bit of bottom end, but they'd need a lot of EQ to sound anything like flat. (boost around 400 Hz, and cut in the 1-2.5k range)

So I've got hold of some 5 1/4"s to play with.
They're only bass/mids, but I've got some tweeters which I'm happy to run high pass on rather than running seperate crossovers. (for the time being - I can always retrofit some crossovers. All they'll do is roll off the top from the 5 1/4"s, so for the moment, I may end up with some frequencies around 4k being reinforced as both drivers play them.)

updates to follow when the 5 1/4"s arrive.

fonzooorooo wrote:

Nate wrote:

fonzooorooo wrote:And then I notice VW's useful vent. (between door card and speaker pod - below my efforts) Why, why, why would they do that?

to allow airflow thru the door to prevent condensation and rusting.

But it's inside the membrane, and effectively only ventilates the speaker pod itself. The only metal in there is the basket of the speaker. The drain holes and ill fitting window rubbers take care of ventilating the door cavity. Or am I missing something?

iirc, there are vents that let air enter the door from inside the car (nice toasty warm air from you having the heater on) then leave to the outside world thru the vent on the end of the door

Nate wrote:

fonzooorooo wrote:

Nate wrote:

fonzooorooo wrote:And then I notice VW's useful vent. (between door card and speaker pod - below my efforts) Why, why, why would they do that?

to allow airflow thru the door to prevent condensation and rusting.

But it's inside the membrane, and effectively only ventilates the speaker pod itself. The only metal in there is the basket of the speaker. The drain holes and ill fitting window rubbers take care of ventilating the door cavity. Or am I missing something?

iirc, there are vents that let air enter the door from inside the car (nice toasty warm air from you having the heater on) then leave to the outside world thru the vent on the end of the door

but theres still a plastic sheet between the two halfs!

...john hows the build going? I'm looking at stating mine soon!!! (christmas day i seem to be doign nothing!!!)

update:
the 5 1/4"s arrived. (I hate paying more for postage than goods!)
I've chopped some holes in a piece of MDF, (to fit the speakers) marked out some approximate outlines (for the pods) , and won't get any further till I take the door cards off the car. Weirdly, I've hd a few guitar jobs in, so car audio's on the back burner for a few days.

Popped the old-skool Pioneer 12" in the car (in a sealed box that's too small, but wadded, and sounds pretty even on test) ... Had the radio on yesterday and roughly set it up. Fished DJ Shadow out today... It's fantastic. Clean, clear, every note spot on, with none of that "bloom" you tend to get on the bottom end of a lot of modern subs. Think I may even prefer it to my Rockford Fosgate - sounds more natural. More importantly, knocks the 10" I was running before out of the water.

The door builds are now complete. I'm playing with paint finishes to save vinyl work. Pics later today.

They look like this:

After being painted with this:

See where I'm going with this?:

Then rattle can black:



Pic fitted to car to follow...
I made some MDF rings/holders for the old PG tweeters, and gave them the same paint treatment. I've mounted these directly above the woofers, angled up/back slightly.
Bear in mind this isn't about ultimate sound quality - just something that doesn't annoy me...
The whole system's pretty old skool... The speakers are Longmills (!)

Now that lot's in, it's a built-in sub box next - get rid of this horrid autoleads box

The "build shots" of the sub box. 2 sheets (2'x6') of 18mm chipboard went into it.
The box is small, but is designed to be wadded. That increases the "perceived volume" of the box by 10%.

VERY nice bass box... I'm guessing that's going to be living in the boot where the tool holder bit is?

it stands in the nearside of the boot, with the funny bulbous bit on the back sitting over the chassis leg and under the parcel shelf support. Pics to follow once I get round to pointing the camera at it...

As promised...
Front speakers look like this:

Only a quick job on them - but look pretty good considering it's a paint finish!

And the sub:

The carpeting isn't the finest (foam backed black cord from the carpet shop - £8 for 6 feet off the roll) but it's going to have a cover which'll box in right up to the seat back and up to the back of the car and will incorporate a grille for the driver and tidy things up nicely.