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I'm getting the install done on Saturday by a reputable guy at Tweeter here in VA. 4080's custom box looks absolutely incredible, and I can't wait until the work is done. I will definitely post pics! Here's my question:
For the sub itself, I'm putting in a JL 10W6v2, which I am told is a great sub and fits the box well. However I'm holding off on an expensive amp because my friend is giving me his for free. It's an off-brand...Prestige 500W 4-channel with a crossover and it will only be driving the sub. My technical knowledge is sub par in this realm so I'm looking for advice. I have the Bose system so I'm running the amp out of the rear speakers with the line-out converter I believe.
How much will this off-brand amp affect sound quality? If it doesn't sound optimal I will splurge for a better amp but I want to try this out first. I want to get some thoughts from you audiophiles on this one!
Thanks. :D
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I'm not sure how this will work since it's a 4-channel amp. 4-channel amps are mainly used to run the speakers in your car and not your subs. Since your are only running one subwoofer, I'm not sure how you would wire a 4-channel amp to it. It might be possible, but Iyou might not be pushing enough wattage to the subs. Maybe you should look into buying another amp. Anyone of you audiophiles care to help out on this one?
when an amp is bridgeable, you can join two of the channels together to form one channel with more output. The sub needs only one channel. You'll have to check the amp to see if this is possible. Most do, but the prestige amp is junk. You can try it out to see how it sounds. If it's tolerable until your buddy gives you a better quality one, do that.
Amp wattage is very misleading. What you really want to see is RMS (continuous) power wattage, not peak (like advertised). The 10w6v2 requires 300-500 rms wattage. There's no way that Prestige amp outputs that, not to mention the sound quality coming out of it.
I also have the 4080 box with a 10w6v2 and I splurges for jl 500/1 amp. It's worth the money,imo. There are pics of the set up here somewhere.
Napboy explained it well. What a crossover does though, is split a signal into a high and low. So, for instance, you can take a signal from a head unit and separate it into a tweeter and a woofer.
If you can, just get a new amp. The sub will only be as good as the sound coming into it. RMS power is key, but so is distortion. You want an amp with a low THD (total harmonic distortion)...preferably around .05%
I am one with vast amount of audio knowledge. For more pertinent info, PM me or even better is to post on www.the12volt.com in the car audio forum. I have the same user name there. The Prestige is an off brand amplifier. The power claim that it makes is highly exaggerated. The dangers of using a 4 channel amp to drive a dvc sub are well documented. First off the crossover points need be identical (the little hash marks on the end cap are within 20% of the indicated value usually). The next issue is the gains also need to be identical. Any difference here (or difference in the efficiency between the bridged channels) is a recipe for disaster. This is due to the fact that unless a oscilloscope is used to set the gains, there is always going to be a difference in output levels between the bridged channels. For lack of better words that are easily understood, this will cause the coils to work against each other instead of with each other.
The use of a underpowered amp on a sub is fine, PROVIDED that the gain is set properly. You can underpower a sub (or speaker) all day long and it is totally safe to do so, just as long as the gain is set correct. The gain is not a volume control, it is designed to be turned down and not up. With a small amplifier on such a large sub, the tendency is there to increase the amount of gain, this in turn causes the ouput stage of the amp to clip (distort) and throw a clipped signal into the sub for it to reproduce which it will do faithfully until the sub dies.
Next up, do not use the ligh level input leads on the amp. You unfortunately need to invest into a proper line output convertor. In this vehicle I would look to a Audio Control LC6 + bass remote or a 6XS. Both of these units will afford you a far superior interface with the factory Bose amp in the rear center parcel shelf and afford you the capability to control the subwoofer indipendent of the main volume control up front. It will also allow you the capabilty of expanding the system in the future without replacing the factory head unit.
Thanks everyone - that is some kickass advice forbidden, and I didn't get that from the install shop. I hope they know what they're doing and set the gain level correctly. I am already looking into a JL 500/1 amp. I'm assuming they would be easy to swap, like a "plug and play" type situation after the crappy amp is already installed?
Yes and no, you will have to go through the gain setting again and right now I would be on the phone ensuring that they run power and ground (4 gauge minimum) from the battery for the new amp to come, otherwise you will be paying again to replace the wire and the time to do it. You heard correct as well, the ground return in this car is absolutely crappy, upgrade all ground from the battery at the same time, battery to chassis, battery to engine block and battery to amplifier ground direct. DO NOT USE THE CHASSIS OF THIS CAR AS THE GROUND RETURN. In a basic system you will be fine, in a high power system that draws current like the 500/1, a small problem at low volume becomes one huge nasty water retaining sea cow of a problem at high volume. Read my grounding sticky on my home forum. www.the12volt.com in the car audio forum for a better understanding on why this needs to be done. 99% of installers do not check the most important wire in the system, the ground.
I am using a six channel amp, and I am using the two sub channels on a dual voice coil sub, as the two sub channels on the amp are MONO, therefore I do not have to worry about output levels as there are no adjustments to adjust the impedance or if you are an electronics engineer like me, Z is referred to as impedence, sure you can use an oscilliscope to adjust your output levels, but if you want to adjust it with some authority you will use a spectrum analyzer., what is that you ask?> well if you have to ask what a spectrum analyzer is..........then you probably better hire an engineer to install your system, like me!
I did my system with a six channel infinity amp, it is not super high power, medium if best, but it works, and I considered weight, so one 6 channel amp, and one dual voice coil sub, and of course a 1 farad cap, farads, henries, Z, kerchoff, series, parallel,
and yes I did use 4 gauge power and ground, and of course a line level input conditioner as that dude mentioned, unless you change out your BLOSE head unit and have pre outs and shielded rca speaker cables and yes when I threw away the mazda battery and installed the optima yellow top I replaced both cables to the batter and used 4 gauge gnd.....to the chasssis!!!!! MUHAHAHA
Last edited by Purple Helmet; 05-02-2005 at 11:49 AM.
Thanks everyone - that is some kickass advice forbidden, and I didn't get that from the install shop. I hope they know what they're doing and set the gain level correctly. I am already looking into a JL 500/1 amp. I'm assuming they would be easy to swap, like a "plug and play" type situation after the crappy amp is already installed?
Installed over the weekend...will post pics shortly! it looks awesome, and for having such a crappy amp it sure does thump quite a bit. I did just win a bid on eBay for a slightly used JL 500/1 amp which I couldn't pass up for less than $200, so I will be swapping them out soon and I'm hoping there is a difference!
Any predictions on what the difference will be? The crappy Prestige amp is definitely working.
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