98 XJ Infinity Premium Sound Components

[Dirk Funk]

One final note since you seem to be interested: It will sound better if you install the new crossovers. Without them here is what the system is doing:

A channel of frequencies is sent to your woofer. It will try to reproduce all of them, but due to the nature of the speaker, it can't and will produce low and mid tones; high tones will be produced, but the dBs will be so low you won't hear them - the point is you are wasting power (Amps) recreating sound you can't hear.

The same channel of frequencies is sent to the tweeter, but a cheap "crossover" is built in to keep low frequencies from reaching it and damaging it. Really, this crossover is a sharp cutoff on the spectrum and low tech.

What the new crossover will do is send the appropriate frequencies to each driver; woofer and tweeter but with a 6 or 12dB rolloff which will ease the transition between which frequencies make it through and which don't = better sound. Better components are also used.

I hope I have helped, and I hope it sounds how you want it.

 

[bbolander]

The new Infinity Reference crossover has two terminals for the tweeter power. One of them is to reduce the tweeter output level, and inside it says -3dB at this terminal.

Anyone have recommendations on whether I should use the reduced output terminal?

Thanks,
Bruce

 

[Dirk Funk]

Since the tweeter is going to be higher up near your ears, instead of say in the door, it might be a good idea. Plus, if it were me, I would want the woofer/midrange doing most of the playing; the tweeter in my opinion is just there for the really high range stuff. And if it doesn't work out right, you can always change it right?

Sounds like this is gonna work out for ya.

 

[bbolander]

The new Infinity Reference Speakers are in now and they sound absolutely great, so much better than the original speakers. I'd highly recommend them to anyone who is staying with the stock head unit and 100 watt amp and just replacing a blown speaker.

Dirk Funk was absolutely right on the crossover not being close to the woofer. On my first test I laid the crossovers inside the door just under the woofers and got sound distortion in both woofers (that was depressing). When I mounted the crossovers with velcro on the doorskin inside the door just past the power window motor the woofers worked fine. That position is probably 6"-8" away from the woofer. That's about as far away as I could get on my XJ inside the door since there's so much stuff in the way with power windows.

I tried the tweeter positive wires on both the full power terminal and the reduced power (-3dB) terminal on the crossover and listened to them both ways. It depends on how much you like to hear the highs. With it on the -3dB terminal most of the highs I heard were from the rear 2-way speakers. I ended up putting it on the full power terminal because I like hearing the highs a little stronger up front.

The Crutchfield speaker harnesses worked perfectly, clicked right in. I did all my wiring and soldering on the kitchen table so the wiring was all complete before I took the door apart to put it in. I'm glad I did, it's a lot less stressful than trying to do it as you install them. I soldered and heat shrunk all the joints since I have had crimped terminals relax after a few years and create a loose connection. I connected the crossover to the Jeep power connection at the woofer and left the Jeep power connection to the tweeter unused. The XJ wiring has the woofer and tweeter wired in parallel since there is no crossover in the amp.

Mounting the tweeters on the flat mirror covers for a 2-4 speaker XJ turned out very nice. I have pictures if anyone is interested.

I think I'm hearing a little base rattle in one of the rear speakers. But they are easy to replace under warranty if I have a bad one. We'll see how it goes.

We CANT turn the volume up nearly as high as we used to or it is too loud for comfort.

My wife just came home from work and heard them - she was blown away! It looks like we're going to be riding around tomorrow listening to CDs!

Thanks to everyone for their help - especially Dirk,
Bruce

 

[Dirk Funk]

I am glad I could help
It sounds like everything worked out how you wanted it to.

 

[phaythe]

One of THE best tips I can offer you is to choose speakers that are rated at least 20% above the outputs you plan to connect them to (remember this for future planning) and if you replace one, try to replace all of them before you lose the rest.

I stumbled across this thread looking for info about replacement tweeters for the system in question (although I have a '97, essentially the same thing, just a few different part numbers).

Wouldn't have had anything to add, since I tend not to like reviving old threads, but I had to correct this misinformation as it is quite important...

NEVER buy speakers using this "logic." You will end up with damaged voice coils in a hurry. If anything it should be the other way around. You should always match your speakers and amps such that the amp can deliver at LEAST if not MORE power than the speaker's RMS rating. Otherwise you risk "clipping." This is far more harsh on a speaker than delivering too much power ever is. Well, unless you toss 100W at a 10W speaker, but then you are probably the type of person who either ends up with a Discovery channel series or a Darwin Award...

This is not as much of a factor in a confined space like a car since you usually can't crank it up all the way anyways, lest your ears begin to bleed. But, it can happen. Clipping occurs most often in systems that have extremely underpowered amps, due to the listener wanting the system to just that much louder...and then just that much louder...and eventually they have the output of the deck and amplifier cranked up so high that your sound signal becomes a DC signal!!! NOT good for the voice coil of the speaker as it essentially is beating the poor thing from "wall to wall"... For those who don't know much about speakers, if you have ever watched a large subwoofer with a large amount of excursion (how far the cone can move in and out), you can see the cone physically moving. If it were clipping, you would literally see it in two positions, fully extended outwards, and fully compressed inwards. This makes the coil heat up, and fail...

However, bbolander, it sounds like you will not have a problem like this, as you complained about it being too loud before the head unit is at full output, but if you ever do manage to go deaf enough that you can get it all the way up (this is my problem, hehe), resist the temptation! With the stock 100w amp, you will damage the speakers you have purchased, which is not fun... If you want more sound, get more amp...

 

[Gridikal]

I disagree, although most speakers could handle a liitle over, it is for a good reason they are rated the way they are. Manufactures have a min and max rms rating... ex 7-35 watts rms. While the speakers could handle the extra power, you have to take into account heat as you said. Extended listening yeilds more heat if you increase the wattage. So insted of killing the speaker quickly as you will with clipping, you will still kill the speaker in the long run.
In a sense I do agree with you though, above that only holds true if that is the actuall rms rating, I feel there is nothing wrong with say, buying a 175 watt rms mono block amp to push a 150 rms sub. The typical audio system will not see the 175x1 rms. So in a sense, youd be matching the amp to the speaker better. The are pittfalls either way, every system has its limits.

 

[phaythe]

I am not suggesting that anyone attempt to power a speaker at more than it's RMS wattage. That is also a definite killer. However, having the power to go all the way to that point, will ensure that you NEVER encounter clipping. For the most part, as I said, especially in a car, if you're inside, your ear drums are going to pop before you can reach even 75% of the RMS power of your speakers...

The other benefit involved in this, as an amp reaches 100% of it's power, it's THD goes nuts. If you purchase an underpowered amp, not only do you risk killing off the $300 pair of speakers you just bought with your $70 amp, but for the time it does work, it is going to sound like crap. You are far better off spending the money on a good high powered amp and buying cheaper drivers, and using common sense when hooking up your speakers.

And of course, properly installed, you will set the output level on the amp, with the input from your head unit at max (assuming that the head unit is designed properly, IT won't clip at max volume, unless what is being played is not properly mastered), as close to possible to the speaker's RMS wattage (duh). But practically NO ONE takes the time to do this. Sadly, I've encountered a couple stereo installers that don't even do this :/ I've ended up fixing a few friend's stereo setups after they've had them "professionally" installed...

And it is easy to do! Get a power resistor that matches the impedance of your speakers. Hook this up in place of the speaker. Get out a voltmeter and read the voltage across the resistor, square it and divide by the impedance...Congratulations, you now know how many watts RMS your amp is delivering to that channel, use the trim on the amp to adjust accordingly...