I have a Pioneer DEH-11 & a Jensen 500W powering 2 8'' Rockford Fosgate Subs. Now I am wondering what to replace the stock speakers with, I got two 6 1/2 Pioneer 80W but I dont know the quality of them.. So I figured they will work as front speakers am I correct? What my real question is what size do I need to replace the rear speakers? one of them is totally shot. Do I just need tweeters or what?

Thanks

 

IF I REMEMBER CORECTLY THE REAR SPEAKERS SHOULD BE ABOUT 4X6. I REMEMBER THEY WERE AN ODD SIZE IN MY FRIENDS 92 F150, , BUT TO BE SURE I'D PULL THE PANELS AND FIND OUT. SORRY I CANT BE OF MORE HELP.

 

check out crutchfield.com they will be able to tell you what speakers fit your truck

 

There are several things to consider when you replace speakers in a truck or car. You do not want to buy tweeters. And the rear speakers you have now are probably not a good choice to put in the front for at least 3 reasons. 1. Age - the cone material dries out with age and you lose some high-end response. 2. They are probably single core type - meaning good performance in a narrow range of frequencies and 3 they are probably too large physically to fit in the front. The quality of any sound system is not based on the total "watts" of power. That is a commercial sell-point. It is better to hear the detail than the loudness of sound. You should have multicone speakers in front and rear. The larger the surface area, the better it produces low frequencies. A small cone is good for higher frequencies. A muticone speaker combines the best of both. A large surface for lows and a built in smaller cone in the middle for the high sounds.
You will probably have more available space for the 6x9 or whatever size you fit in the back. If your front speakers go in the door - they will have to be smaller to fit. Probably 4" or 5" round.
Be sure that the door speakers do NOT get wet when it rains. Your window molding should be in good shape. Also be sure to observe polarity. Home installers often get this messed up and the end performance suffers. Here's the secret. If you touch the two speaker leads to a battery and hold it for a moment - the cone will either have moved outward or inward. If you reverse the battery, the cone will reverse. Now check your other speaker and assure yourself that it moves the same way as the first one. Chances are real good that the OEM did it right and your two speakers are in correct sync/phase. If they are not - just reverse the wires on one to match the other. DO NOT attempt to unsolder the cone wires... that's a kiss of death for the speaker. Any reversing should be done to the wires that attach from the amplifier. Another real important point for a good installation is this --- the air on the front of the cone must never touch the air on the back of that cone. In other words, the air in front of the speaker must be isolated and sealed from the air behind it. You do this by being sure the metal on the truck is smooth and clean when you mount the speakers. Then be sure to bolt them tight but not overly so. You do not want ANY lose screws. What I do, when I have everything the way I want it.. I apply a small amount of silicone seal to the flange of the speaker. It really blocks the air from mixing. Mixed air gives a muffled sound to the finished job. I have seen many professional installers fail to understand this critical point. Another thing is to pay attention to what is around the mounting hole itself. It defeats your whole purpose of air-blocking if two inches away from the edge of the speaker is a significant hole in the sheet metal. At the very least, cover as any holes as you can find with 3 or 4 layers of duct tape on each side of the hole. Stiffness is important. You do not want a thin strip of tape to resonate with the back air.. because it will produce air compressions in the front. By the way, this is the technology for blocking sound... It's like when you hear a sound, your ear also is struck by the phased reversed image of the original sound... thus you hear nothing. When the back air and front air mix.. you get a smaller degree of this sound blocking effect. There are other things to consider such as impedance matching the speaker to the amplifier. Just be sure that your speaker is matched to the output of the amplifier. That way it will deliver the maximum fidelity and output. One more thing, don't rely much on what your ear hears in a store speaker rack where you can switch from one to another speaker. Use that as only a general guide or indication. Why? Your truck acoustics will be far different than the store environment. Most of the major brands today produce fairly good speakers. Let price and specs guide you as much the sound you hear in the store. If you do these things, you will end up with a properly phased system that produces good qulity sound at even low levels. Good luck... sorry for so much info.. my fingers get on a roll :-) Rolling Thunder Rick the wolffybear

 

Hey man welcome to FTE, and thanks a ton for all the info!

 

Thanks for the welcome and glad to be of some help. I'm already finding other topics that are of help to me. It's great to have such a broad range of knowledge available.

Good luck with your speakers...
Rick

 

If you can't tell the polarity, try switching them w/ the sys on...you can hear the difference on the low end- If Bass DISAPPEARS, you've got 'em wrong...

 

I dont agree with switching the speaker wires with the system power on. Sounds like a good way to tear something up.

 

I agree about the risk of switching the speakers wires while hot.
Speakers are an inductive load (though very low Z - impedance). When unhooked hot, the field collapses and rushes back into the power amp output at just the moment when the wire is just slightly off the terminal.

This is part of what makes the spark as you remove the wire while hot. As long as the wire is physically touching the terminal, the field will not collapse. But as soon as the wire is ever so lightly off the terminal the field will wildly fall, jump the air gap between the terminal and the wire and rush madly back into the output circuit. If it is fused, and the wire is pulled off playing music loudly it is possible the fuse will blow. Many are not fused.

By the way this leads me to another but related problem with modern IC (chips) especially in car stereos, car/truck computers and all digital computers and devices (radar detectors, alarm systems etc)

The speed of the chip is the direct result of how small and how "close" together the tiny transistors, resistors and capacitors inside are together inside the chip.

In older chips the parts were bigger and farther apart. Thus the electrons had farther to travel and took longer to make the trip. This was the limiting factor on how "fast" the chip was. It's expressed as the "frequency".

As technology improved the parts got smaller and could be placed closer together.. thus the path was shorter for the electrons to travel and the trip took less time. The "speed" went up. We see this in advertisements all the time - especially in computer ads. It used to be 1 Gig Hertz (one billion cycles per second). Then things got smaller, the electron travel time got shorter and the speed went up... 1.5 GHtz... 2.0 GHtz etc.

Sometimes we are dazzled by all of this digtal talk and high speed performance. It all comes from just one main thing... the physical size of the tiny componet parts inside the chip. That's it. Of course there's more to it but that's the main event.

But a real problem happened. As the parts got closer, the gap between shrunk and the voltage required to jump the gap went down too. Simple static electricity in your hand makes enough voltage to "jump" that gap and fry modern chips.

Lucky for us that static build up in our body produces only extremely small "current". The voltage is way up in the 1000's of volts but there is almost no "current" behind it. Wow - if there was we would be leathal to each other and everything alive.

Car/truck stereo output amp cuircuts are very low impedance and can handle most heavy zaps. But if you get inside the radio case and have to check or replace anything be sure you are VERY well grounded to bleed-off any static charge from your hands. Same is true for TV's, your desktop PC, home alarms, video camcorder, car/truck emission computers etc.

Otherwise you risk frying high impedance chips with just a touch of your finger. Or worse yet, you risk damaging it but it will still work.. sort of. Then one day when you are on a trip in Death Valley or The Bad Lands 100 miles from nowhere... the truck stereo or ignition computer or whatever was worked on will give a final sputter and flat out die.

In fact you should ask a few questions of your repair shop --- "do you have and use wrist grounding straps when you are working with the "case-off" on my electronics?" If they chuckle... leave and find another shop.

OEM's design electronics to be static-protected when the case is on. When it's opened up... that protection is gone.

It's best to wear a static-grounding strap on your wrist. Don't try to make your own from wire. Not a good idea. You can buy them at Radio Shack or other stores for a couple of bucks.

It's one of the problems we have with spacecraft. But the worst part is that the static zap does not always fry the chip completely. It might still work and pass tests but have greater "uncertainty". It can fail easily from just normal use.

Not a good thing to happen when the spaceship is already "on-orbit" or heading to Mars. We found that even a piece of scotch tape when removed produces enough static electricity to fry modern chips. Not a slam at scotch tape - it's great stuff. They did finally figure out a way to make scotch tape that makes almost no static electricity. But the regular kind you buy in stores makes ESD (electro-static-discharge).

In older am/fm models I have also seen blown power output transistors caused by accidently shorting the output leads together.

The idea that improperly phased speakers will produce a somewhat muffled sound is very correct. The amount of muffling you hear depends on speaker placement and distance apart. And reversing the leads "of ONLY one speaker" is the right thing to do to test it out and correct the problem... It does not matter which speaker you reverse - just don't reverse both of them or else you will not correct the phase problem.

If you have four speakers in the rear... the phase problem is a little more complicated to solve. In that case, use the DC (battery) technique I described previously. You want to have all four phase-matched together. No 180 degree shifts in phase. However if you have a good ear.. you can do the dynamic phasing as I just described above.

What is phase matching? Boiled down it just means that when a certain tone of music makes the speaker cone move outward... you want the other speaker to also move outward when it produces that same tone. Reversing the speaker lead wires will also reverse the way the cone moves.

In any case of dynamic-phasing, I would just suggest turning the stereo off first and waiting a few seconds for bleed-off before removing the leads from the speaker. Then reverse the leads and power up again.

Good luck to everyone. So sorry for the rambling... need to work on writing shorter... :-)
Rolling Thunder Rick Wolffybear

 

If you listen closely, you should be able to point at a speaker out of phase...but then again I did tune cars for quite awhile...

Maybe I should have clarified- Don't tap the speaker on and off when testing, and keep the volume DOWN. Today's stereos can handle a lot of abuse- won't be an issue...

Wolffybear is correct though in everything he said- especially when working with chips directly! But w/ car stereos, again- It won't be an issue...

 

navymac is correct about modern car stereo system taking a lot of abuse. I also have many years of experience. I even remember vac tubes!!! :-)

My advice was directed more at folks who have good skills and like working on their own equipment but lack a lot of experience with the subtle points.

Good luck to you guys..
Rolling Thunder Rick Wolffybear

 

Vacuum tubes aren't so old- I still have 'em in my truck