>

>

> Dan,

>

>

Not usually, once the response is averaged a bit. All I usually see is

increased grass in the response - the general shape is still there. In the

initial 3 mSec, especially in a car, you'll get 99% of the actual response

curve. Anything beyond that distance really won't impact you too much. At

least, that's been my experience.

My oh my, where to start...:) For starters, the car is a 1987 Ford

Thuderbird TurboCoupe. Two door. Front midwoofers located in stock door

locations, tweeters in the dash locations. Subwoofer in the rear deck, firing through the rear (shaved the underside of the deck carpet and removed the padding directly over the sub).

Anyway, I put in new drivers: front is a full set of drivers from some

Paavanis. Use to be some Focal 6K218 woofers (real nice bass and lower

mid, but bad breakup around 2.6 kHz), with some Focal TN46 tweeters (nice

sounding, just a bit zingy. Still, I only got rid of them because I wanted

to play with some new drivers).

In the rear, I tossed the old JL Audio 10W5 (operating in free-air; don't

listen to those JL guys! The 10W5 works wonderfully in free air!) for a

pair of Morel MW224s. Really didn't gain any more bass, but reclaimed

about 4" of depth below the deck (those Morels are 2.125" deep, as opposed

to the 6" for the JL). Stuck the Morels under the stock 6x8 speaker

openings, mounted the amps, XO, and EQ between them, under the rear deck.

Covered all with a nice little cover, so that you see nothing when opening

the trunk.

Anyway, I upgraded from an AudioControl EQL to a HiFonics Plato. I really

like the variable center frequencies of the Plato - came in quite handy!

Also went to a tri-amped solution: from a single Hafler MSE100 amp with

passive XOs to a custom active XO driving three KLW/Carver XA50 Broadway

amps.

The goal of the redesign was to claim back some trunk space, clean up the

upper mid, improve imaging, and not lose any of the bass. The new

midwoofers really helped in the upper mid department. The Morels kept all

the bass, but gained trunk space. And the custom active XO (6th order slopes) really helped the imaging - but then, you know I advocate high order slopes for superior imaging...:)

Also got a chance to fix a few EMI nigglies (the T-Bird has the ABS and

ride control computer mounted against the back of the rear seat. When the

ride control or ABS would engage, I'd hear quiet clicks in the stereo).

Pulled out some bad power wires, replaced with quality welding cable (don't

drop the money for the brand name crap. Welding cable is MUCH better, and

a LOT cheaper!). Also ran new RCAs, made with Phoenix Gold connectors

(from the previous cables - really nice connectors!) and some Belden 8412

cable.

All permanent connections are soldered and covered with liquid vinyl - no

heatshrink or crimp connectors (too much corrosion from the sea air in

Seattle). Temp connections and RCA connections are covered in

anti-corrosion gel for battery terminals. Direct 7 GA wire (twin 10 GA

runs) from the battery to the distribution points in the back. Four 47,000

uF Sprague 88D caps for filtering (I wish those caps were still available!

Some of the best I've ever seen).

All in all, ended up with a system that has better sonics, more reliability

(no more green ground cables!)

From E.N. Murray. A buddy of mine works at Paccar, in the Seattle area.

They build the Kenworth semi trucks - big monsters! Anyway, they line ALL

their trucks with padding from E.N. Murray. So, I got their catalog and

ordered some 0.110" thick asphalt damping sheet. Better than Dynamat

(heavier), with a better adhesive (rated from -30 deg C to +80 deg C). And

the cost was around $13 per sheet (32" by 54"). Of course, I had to order

12 sheets, minimum... I used a total of 4 sheets in my car, and sold the

rest for a bit of a profit...:)

They sell all KINDS of absorptive foams, too. I was tinkering with the

idea of replacing my headliner with a nice foam-covered asphalt sheet, but

the cost ($33 per sheet) was a bit prohibitive. Looke really close to stock, though.

> -----Original Message-----

>

>

Mounted on small panels in the original 3.5" diameter speaker holes.

>

Well, the JL 10W5 has a small signal Qts around 0.46, as I measured it (I

believe the datasheet they supply to dealers stated a Qts of 0.5). The higher Q is the reason I bought it - wanted to do free air.

>

I don't think HiFonics has the Plato anymore... You may find one for sale,

used, though. I purchased my used for $75.

Well, you could just build a custom EQ, and leave the EQ resistors on little

header strips, for ease of adjustment, if needed. A full custom solution

would work great; in fact, I would probably do that, but I'm lazy, and have

the Plato...:)

>

The slopes ended up being anywhere from Qs of 0.4 to Qs of 0.85. Mainly

designed then XO to cure some larger equalization problems I had, and used

the Plato to cure the many small ones.

And yes, especially when the drivers are widely separated, the imaging will

improve with steep slope XOs. If for no other reason than the Franssen

Effect (locking in of localization (delaying the midwoofer a bit WRT the

tweeter will cause your brain to interpret the midwoofer's output as coming

from the tweeter location!). Net result: with the tweeters in the dash of

my car, the image is all right up there, too. Not down in the middle of the

dash or the footwells, as it often is with the current "kickpanel" location

trend.

>

Yes, 8412 is twisted shielded pair (20GA conductors). I run the two

conductors to the center pin, the shield to the grounds. The reason I use

it is that it's EXTREMELY flexible, VERY tough, and I've got access to

around 10,000 meters of it at BioSonics...:) We use it for some SONAR head

cabling. Has very good noise rejection/shielding (we've run 800 meter

lengths on top of dams, with lots of HV stuff around. Typical signal levels

for SONAR are around 10-20 mV. We still maintain S/N of around 95 dB).

>

I believe so. You can purchase the liquid vinyl at most marine supply

stores. It's a little thinner than the handle coating stuff, and comes in a

little bottle with a brush attached to the lid. Just brush it on to the

connection, and let it dry!

>

>

Hey, I figure that if I want/need something, SOMEONE else must, too! :)

AND A BIT ABOUT MB QUART

----------

> From: Jason Cuadra <JasonCuadra@-stec-power.com>

> To: bass@mcfeeley.cc.utexas.edu

> Subject: MB Quart tweets

> Date: Sunday, December 27, 1998 1:21 AM

>

> Dan wrote:

>

> Speakers? Well, MB Quart were considered the finest in car stereo for

> many years (we're talking back in the early to mid 80s). "Accurate" high

> end. Detailed. Everyone who heard them said the same thing. Of course,

> that's how the speakers were described to them - detailed and accurate!

> Compared to a good pair of A/D/S/ units, though, and the shrill nature

> was revealed (heck, one need look no further than the output of an

> AudioControl SA3050 for proof of the shrill/peaky nature of those

> tweeters). Yet people expected they'd sound a certain way, and by golly,

> that's what they did.

>

> OK, so it's not just me. Those things bite!

In more ways than one...:) I never could understand $150 for a pair of

zingy tweets that sounded bad, and couldn't reach below 5 kHz without

extensive breakup...

> Say Dan, it's not just that their levels aren't set too high? What

> does its f/r look like?

Well, back in the late 80s, all I had was an AudioControl SA3050 RTA.

Good, but not quite LAUD, or IMP, or MLSSA. As far as the response of the

1" units, Fs was around 4 kHz. Q around 1.2; real second order drop-off

from about 3.3 kHz on down. Above about 8 kHz, they rose at a nice 6

dB/octave rate; almost 10 dB of peak at 20 kHz. All together, a near-smile

response, with around 2 dB peak at Fs, and 10 dB at the high end.

> Cheers,

> Jason

Dan