stevie-thanks for the reply...when it comes to car audio, i am truly a newbie. most likely i will get the Vifas(just need to get something for the rear door too). if so, which of the Audax tweeters would be the right match sonically without too much work/mod? which is the neodymium type?

TIA

william

 

gs4 - replacing your stock bass/mid with the Vifas is pretty straightforward - you just open the baffle hole a bit and screw them in.
The front drivers have a 3.3 microfarad capacitor attached in series with the tweeter. I would definitely recommend replacing this cap with a polypropylene type. If you do this, you need to glue it to the Vifa, preferably at the side of the magnet, because you won't find any glue that sticks to the polythene cabinet material. Make sure that the leadout wires of the cap cannot vibrate, i.e. don't leave them hanging in mid air. I have found that silicone sealant does an excellent job for gluing and damping at the same time.

The wiring is pretty straightforward. You basically duplicate the wiring you see on the stock driver, running a cable from the Vifa to the tweeter output socket in the plastic cabinet, with the cap soldered in along the tweeter positive line.

If you want to replace the tweeter it gets a bit more complicated. The one I have in my system at the moment in the AudaxTMO25F7, which has a titanium/plastic dome and is in a different league to the stock tweeter. I can recommend both this and the fabric dome version. You need to cut and sand the faceplate down so that it fits in the tweeter pod. Seal the top of the tweeter - over the dome - with several layers of Scotch tape first.

You cannot use the standard fixing bracket to attach the tweeter, as there is no corresponding hole in the back of the Audax. Use silicone sealant again and leave it overnight to dry.

Because the Audax has a short horn, it doesn't mate flush with the baffle hole in the pod. To reduce reflections from this overhang, apply silicone sealant so that the horn finishes flush with the baffle.

The Audax is more efficient than the stock tweeter and you should reduce its sensitivity using an L-pad. This consists of a 3.3 ohm resistor wired after the 3.3 mF cap and in series with it, and then a 10 or 15 ohm resistor in parallel, or across the positive and negative.

from Vifa + ----[3.3 mF cap] --- [3.3 ohm resistor] --- socket

The 10/15 ohm resistor goes after the 3.3 ohm one at one end and to the negative cable at the other. Unfortunately, that's the best diagram I can do using text. Use wirewound resistors between 9 and 11 watts.

If you want to use a more sophisticated crossover I can provide details but you will have to source all the components (which are freely available) and solder them all up on a board.

Some of the above will only be clear when you have the parts disassembled.

One word of warning. Make absolutely sure that the front and back shells of the cabinet are sealed. The gasket is reuseable, but if any of it has torn or deteriorated drop some silicone on that spot. Even a small leak here has a drastic affect on the bass response of the speaker.

Stevie

 

Percy, have you experimented with aiming of rear speakers? Would they be better aimed at the front of the car or at the opposite listener rather than straight up in the rear deck? If I were to tackle rear fill at some point, I'd be up for aiming them and rebuilding the rear deck integrating pods.

 

Kyle,

I've tried it both on the rear deck (previous installation) and in the GS (lower knee area). I'd say that the main important factor would be the actual level (sound/loudness) of the rear speakers. In both installations I've had the rear speakers wired out of phase...and it sounded better for it. (Actually, the Mc processor that I have does it at a touch of a button.)

Best bet is to incorporate tweeters in the rear, but keep them well "padded" to prevent dragging of the soundstage.

I haven't tried different aiming techniques (pods), but I would guess that two different locations would count as a sort of aiming experiment. The pods sound like a VERY interesting experiment!

Percy

 

Just doing a double take on this, Percy. You recommend wiring the rear speakers in the GS out of phase?

Stevie

 

You got it! Wiring them IN PHASE will cause problems. I've had better experience wiring them OUT OF PHASE.

Percy

 

Wow! Thanks, Percy. I would never have thought of doing that in a million years.

Stevie

 

Very low level is definitely key, I'm not sure what would be better to replicate the sound reflection, speakers right at you or reflecting off the rear window; or if there would even be a noticeable difference at the level the rear fill would be playing. At least for me, I'll admit my ears aren't near as sensitive or distinguished as true audiophiles like Percy.

I've heard the idea of aiming the rear speakers thrown around before but no solid testing of it; the CEO or Arc Audio's car was in one of the mags a while ago and he had comps aimed in the rear deck with kickpanel like pods, I'd be interested to hear the results; but I'm having a hard enough time finding time to work on my front stage and subbass install, I don't think rear fill is gonna be happening anytime soon. Maybe when the car is parked for the winter.