The problem with front and rear speakers is the stage. The stage is where your brain perceives the 'sweet' spot when listening to music. Rear speakers are fine in an SUV where you have a large cabin, but in a Vette, with a small cabin, the rear speakers move the stage back behind you and this confuses your brain. Do you ever go to a nice big concert and sit backwards? That's the effect of rear speakers.

Now, you mentioned putting the 6.5" or keeping the 6x9" speakers in the rear for bass. The simple truth is that adding more small drivers will not add more low frequencies when the cone surface and linear travel are not enough to generate nice low frequencies to begin with.

Bass is not directional which is why subs are best used out of the way, behind everything, and out of sight. Mids and highs are very much directional, and are best suited for front listening.

The Polk 6.5" speakers will indeed fit in the kick panels with no modifications to the birdcage...just holes in the kick panels for the speakers, and external grills.

The 4 channel amp is ideal because it's a singular unit capable of powering both the front speakers and the sub, saving room, and giving the speakers the much needed boost in wattage over what the head unit could not provide.

You will be very happy with just a single set of coaxials in front, and a sub in the rear. You'll have lots of low frequencies, punchy bass, and clear mids and highs.

 

Excellent...6.5" DB651 speakers are ordered. I'll get all the parts then drop you a line. One final question...where do you buy (or do you even need?) the adapter box to hold the Excelon HU after chopping the bezel? I have an old link to millionbuys but I can't find the item?

Thanks as always for your help and insight, S

 

You won't need to order anything else for the gauge bezel you have. It's a flat surface so once you cut the DIN opening, you install the cage that comes with the head unit. I can help you with all of that when the head unit arrives.

 

Here is what my set up looks like installed in my 77 with a little help from Matt.. ..
Alpine head unit. Infinity Kappa series 6.5 front and a MB Quartz 10in sub with a 4ch Cadence amp

Good luck and lets see some pics when done.

 

Nice! Did you build the box for the sub or buy it retail? Plans or links appreciated...

DB, the Cadence amp arrived yesterday...looks like a great unit. The installation book recommends direct wiring to the + post of the battery with gauge 4 wire. Is this gauge really needed? Any advice on the actual wiring/installation greatly appreciated. I was planning on getting one of those posts that you screw into the battery terminal to add electronics so I can get the proper contact.

I'll keep ya posted as more parts arrive, S

 

I like the box too... It was built for me by a forum member....He did a great job on it.

 

Yes, you want both the ground an the power wire to be located at the battery. The shorter the better so there is nothing better than the battery being right there in the back. Make sure you have a good fuse between the amp and the battery. I have a battery with both top and side posts and I recommend using the side posts for amp and head unit, so you can use a power disconnect at the top posts for the car and not lose your memory.

 

I only have a battery with side post so i'll have to see how I can rig it. I know you can buy some neat blocks that you screw into the post that have screws for inserting accessory wires. Do you think a Gauge 4 wire is needed? I was looking at a chart on Crutchfield that point to an 8 - 10 gauge being adequate (600W equalling ~90amps).

 

A good rule of thumb is to always respect the MANUFACTURER'S recommendations. If the manual for that amp says 4 gauge, then that's what I would install. Sure, according to averages 8 - 10 might work fine, but Crutchfield didn't make that amp, and MOST of the amplifiers they sell are over rated name sellers that use high MAX watt ratings to sell amps and have very low actual RMS values.

Go ahead and run 8 gauge if you like, as it's your stereo and it's for you to use your own discretion. I personally would run gauge.

 

Thanks DB...I'll follow their instructions to the letter.

Any thoughts/general tips on noise reduction? My current install has pretty nasty whine when I play anything that draws directly from the cars power (ie the HU's cassette deck, a portable CD player plugged into the lighter...) but if I use an iPod plugged into the auxiliary input line from the HU I get little or no whine. The iPod is running on its own battery. I have an aftermarket alternator with no filters inline. The HU does have an in-line noise filter and I have a ground loop isolater hooked between the amp and the HU which actually helped a lot. Thoughts?

Again, all your insight and advice is greatly appreciated an I expect this install will be awesome.

BTW...Polk speakers arrived yesterday. I'll be starting the mods on the kick panels this weekend and get them in place. Just waiting on the Kenwood HU for now.

 

I'm just very happy to help and I hope your install goes well. Take picks of your kick panel modifications and install.

RFI can be a pain in the butt for sure. Aside from the noise filter to the head unit, ways of avoiding it are to power and ground the head unit to the battery to avoid a ground loop within the birdcage as a grounding source. Also, a distributor filter and maybe an alternator filter will help.

A good head unit and a good amp will probably not pick much up. The better the head unit, the higher the line voltage signal to the amp. The higher that voltage, say 4V, the less of a chance it will pick up interference.

Also, spiral core spark plug wires can help a lot to reduce ignition noise.

 

Hey Matt,

I got my Excelon 591 in the mail yesterday so I'm ready to roll. I was reviewing your system design paper and was wondering if you ever did the install follow-up? First step will be to pull and cut the bezel, then mount the cage. Any tricks here? Also, it seems I will be using very few of the original harness wires to make the connections, in fact just the remote antenna out and the yellow 12V constant. Would you recommend bypassing the original harness fittings completely?

Thanks again, Steve

 

Just trace the cutout pattern onto some paper using the included head unit cage and a Sharpie. Cut the opening to small st first, and file the opening out until the cage fits snug. Then install the cage, and bend the little tabs around the edges until the cage is firm in the bezel and will support the head unit. That's all there is to that.

I would bypass most of the factory wiring all together. For best results, run a dedicated power and ground wire from the head unit to the battery along with the remote wire, RCAs, and front speaker wires that will connect to the amp and run to the speakers.

Run the 12V switched source from the fuse panel. There should be an open ACC terminal which will switch on when you turn the key to IGN or backwards to ACC.

The power antenna wire will be the only one you connect to the head unit harness, which should be a blue or blue with a white strip.

 

Awesome...I'll take pix and keep you posted. I'm pretty confident I shouldn't run into any major issues. One final question before I start: what gauge wire would you use for the deicated lines to the battery and how would you install them? Ideally I would want the wires running to a dedicated post so they are always attached and my HU memory is retained but I'm afraid I'll drain the battery (not an issue???). Right now I have a quick disconnect on the negative terminal that I would like to keep to pull the battery off line while it sits. Is it kosher to install accessory posts directly to the terminal then attach the disconnect to this post? I've read that you want the main wires attached directly to the battery with the accessories linked to the terminal and not the other way around like I'm proposing. Any links to sites with the proper gear to use with a side-post battery greatly appreciated.

S

 

The head unit doesn't use much power so 14 gauge is plenty for power and ground. I would run them right up through and under the center console, and drill a hole through the bulk head that will be covered by the E-brake handle. That's where I ran all of the wires for Curt's system, as well as mine.



The head unit, when connected to the battery will not drain it. The memory and clock would draw such a small fraction that it would not even light a small bulb if using a test light. Maybe not even an LED.

I personally like using batteries that have both side post and top post. Any parts store like Oreillys will sell posts that have a small stud the screws into the side post and gives you a post that a standard post terminal would fit on, and many even have a threaded stud on the tip for ring terminals.

If you have a top post only, just find a way to connect the wires to the post before the cutoff.

 

Hey Matt...got the install underway and wanted to place the order for the sub. I found these enclosure pretty cheap on flea-bay. There are also enclosures on the sub site where I'm getting the sub. The eBay ones state they are 0.85 cubic feet while the sub recommends a box of 0.65 cubic feet. Woofersetc doesn't give the specs. Any preferences or thoughts?

Thanks, Steve

http://cgi.ebay.com/ws/eBayISAPI.dll...tab%3DWatching

http://cgi.ebay.com/Single-10-Sealed...QQcmdZViewItem

http://www.woofersetc.com/index.cfm?...roduct_ID=3521

 

Just get the box with the smallest volume, and decrease it even more by gluing in some wood blocks in the inside corners. Get that volume down a bit a little closer to .65. If you want to build one, or know someone who can build it I can email you a box design that I use when I build boxes for C3s. I can also recommend you to a box builder who will make a custom enclosure, high quality, for the same as those Ebay boxes shipped.

 

Please, send the plans (and any other you may have for handling the amp in a '79??) and let me have your contact as well...time allowing I'm certain I could put one together, I expect for a reasonable price.

Thanks again, S

 

Sure thing, I will email that later today when I get home.

 

Cant Wait to see pics on this install....... =)