siberian

Well, as some of you know... about a year ago I did a complete gut and rewire of my A4 stereo. I ripped out the factory head unit and front speakers, ran all new cables, rewired all the speaker cables for 12gage, ran three sets of RCA's to the trunk, and installed a Kenwood eXcelon (KDC-X915) headunit, Kenwood 10-disc changer in the trunk, and Diamond Hex 6.5" separates in the front doors (custom door pods I made). Then suddenly I got the bug to start doing other performance mods to the car so I sorta put the stereo on hold and decided to just slap in my old Clarion weak-*** 30 watt per channel amp and an old Circuit City Special JBL 10" sub in a makeshift box I slapped together out of scrap pieces of 3/4" fiberboard. (you Chicago guys have seen it... it ain't pretty!)and it sounded fine... for the time being. Well, I've finally decided to finish this beast that I started a year ago. I just received the amp (Xtant 403A)three channel 50watts stereo 4ohms, plus 200watts for the sub (at 2-ohms) and my sub (Audiomobile EVO 12" DVC) will arrive on my doorstep tomorrow. The amp is going in tonight... I'll take pictures of the little rack I made. I still have to build the box. I've already done the design work and calculated all the panel cutouts... all I have to do is hop over to Home Depot and pick up the materials and it should only take a couple hours to slap together.

I can't wait to finally finish this thing. Any Chicago area people can see it next Sunday May 6th at the Continental Audi picnic.

Here's the specs on the system... I'll take pictures soon...

98.5 A4
Kenwood eXcelon KDC-X915 head unit
Kenwood eXcelon KDC-CX85 10-disc changer in trunk
Diamond Hex 6.5" separates (aluminum tweets)
Custom fiberglass door pods for the Diamonds
Xtant 403A three channel amp
Audiomobile Evo 12" sub- 1.25 cu/ft enclosure
Rear factory speakers removed- no rearfill
Stinger Dream Series RCA's.
Streetwires power cables and 12gage speaker wire
Streetwires fuse block at battery (60amp)
Streetwires distribution block in the trunk

As you can see, the system is pretty simple.... I actually ran 4-gage wire to the trunk and into a distribution block where it splits into 8 gage for each amp. My original design for the system called for two amps, but then I decided on making it simple and going with just one amp. However, I thought in the back of my mind that somewhere down the road I may want to add another amp dedicated to the sub. So I just went ahead and pre-wired everything for two amps. I ran an extra set of RCA's too... just in case I want to add a rearfill channel. Now I have lots of flexibility and I'm not painted into a corner if I want to add on to the system later on. Even the amp I chose is changeable. As it stands right now, it will be running 50 watts to each of the front speakers at 4-ohms, and 200 watts to the sub at 2-ohms. (yes- you can do that with Xtant because they use separate power supplies for each channel). If I decide later on that I need more juice for the sub, I can convert this amp to a two chanel stereo setup by bridging the front left and right channels into a single mono at 100 watts at 4ohms, and using the sub channel at 100 watts 4ohms. This amp would just be dedicated to the Diamond components up front, then I can go out and add a single mono amp to run the sub. All the wires, including power and ground are in place for the 2nd amp so it will be pretty much plug and play from this point on.

I am using a slightly larger enclosure for the 12" sub because I am running it at the low end of the recommended power. The smaller the box, the less efficient the sub becomes because the air is "tighter" inside and it takes more power to get the full excursion out of the sub. A slightly larger box will allow the driver to move a little easier. I didn't want to go too large cuz I don't want it sounding sloppy. I think the 1.25 ft enclosure should be a good trade-off. If not, then I can reduce the internal volume by inserting solid wood blocks into the enclosure until I get the tightness I'm looking for.

like I said... I'll take some good pictures when I'm done with everything and post them here. Gimme a week or so.

analog S4

If I remember correctly.

Altersys

more power for what? At what frequency? It's more complicated than that....

siberian

in a smaller enclosure, if it is sealed properly, the air is compressed tighter and it takes more power to move the cone.... generally speaking.

The rule of thumb is the larger the enclosure, the easier it is to move the cone, however the consequence is that the tightness of the bass will be sacrificed to some degree.