Installing JL 10tw3 with Kenwood x501-1

You reduce the power handling when you do this. Something to keep in mind. Might as well go with the 8 ohm setup if thinking this way.

 

No, more power is not necessarily better - especially if you don't know when to back off. And again, a 2 ohm config does not void the warranty all other items aside - overamping does. There is no inherent risk with either impedance choice. The only risk is that you will void your warranty or physically damage the sub by feeding it too much power without knowing when to back out of it.

A 2 ohm load here will ask the amp to make more power than the sub is rated. An 8 ohm load will ask less of the amp - probably around 250W or so under normal conditions. All things considered it is the safer bet.

 

I hear ya, but easier said than done. There's no way to cap the output at 28.3V as output voltage relies on input voltage. You can set gains for this target, but all it takes is a track or portion of a track outside of that 'cap' and you go over that voltage. And it still voids the warranty.

 

It’s normal to exceed that voltage anyway. It’s the difference between RMS and peak. With a 0dB reference signal, if he sets output at 28VAC with the truck running, he won’t have any more headroom than he would with a 400W RMS amplifier.

 

I hope this displays normally. My last post appears backwards to me.

OP, your post, #24, the question how many watts is 8 ohms is an apples and oranges question.

Watts is a measure of power. Ohms and impedance are measurements of resistance.
Ohms is straight resistance. Impedance is the total resistance in an alternating current circuit. Inductors and capacitors are frequency sensitive components and change their resistance in accordance with the frequency being applied.

For an inductor, it's resistance increases as the frequency increases. Capacitors, just the opposite. This is why inductors are used in crossovers for low frequency (woofer) applications and capacitors for high frequencies (tweeters).

Rather than me type and type and type; Google ohms law, watts law, and Impedance for more info than you wanted on the 3. If nothing else, you'll gain a better understanding of electricity.

 

Okay, even after reading what you all said 3 times I still got it wrong .
Now I fully understand
I’m going to wire this sub up 8ohms first and see how it sounds. I will set the amp to 8 ohms. There’s some other knobs I will take a picture of and post here to ask for the correct settings. I will also Google it. I have some extra braided 12 gauge wire I will use to wire the sub then tie into the amp wires. I read 28 vac for amp settings at 2 ohm but what VAC should
I set the amp at for 8 ohms?

 

Here is amp settings

 

Where is this, "8 ohm" setting? Amps usually work with what they're given and usually need no adjustment for speaker impedance?

Looking at the 3 adjustments in your last pic; three left most knob is for setting the crossover frequency. Anything above the listed/selected frequency starts being attenuated.

The middle knob, level,... I'm having a hard time trying to describe this one. someone, anyone (with accurate info) throw us a bone here.

The sensitivity knob matches the amp input to the head units output. You want to keep this setting as low as practicle. The amp will run cooler.

 

So this morning I went with what I have learned! I wired the sub at 8 ohms and mounted it in the enclosure put the grill on and plugged it in. I left the amp settings as is because I can’t tell what way the knotch in the knobs is pointing too. I realized I was seeing things when I thought I saw a ohms setting on the amp.. now the only problem is the seat has to be pressed in to get it to latch with the grill on the sub.

 

Here’s the sub behind the seat

 

And I left a screw out in the top left side of the sub because the smallest drill bit I had was
Too big for the screw so I just drilled it in without pilot holes.

 

Also the sub fits
Behind the seat now I took out the plastic panel

 

You don't "set" an amplifier for 8 ohms. You simply apply the 8 Ohm load by configuring your speaker wiring to get an 8 ohm nominal impedance. What kind of power your amplifier puts out is simply a consequence of the electrical values in the circuit.

1. The low pass filter setting.
Where you set this depends on a few things, like the frequency response and power handling of your door speakers. You may also choose to use the low pass filter in your stereo for subwoofer rather than the one on the amplifier. Normal out of the box starter setting for this is 80Hz. If you are using your stereo's low pass filter, set this to its highest setting.

2. The low frequency boost setting.
I never use this and always leave it all the way down. You may choose to use this, just remember that any boost that you apply will increase the amount of energy the amplifier is sending to your subwoofers. In your case especially, since you don't want to overdrive the subwoofer, leave it down.

3. The input sensitivity.
This is where you set the potential power output of the amplifier. Normally you would want maximum power output for a 0dB reference signal, which would provide rated power with minimal distortion and noise. The procedure for setting this correctly varies between amplifier models and manufacturers so it's imperative that you at least read the manual and understand the procedure.

There are more ways to use input sensitivity on an amplifier, but it's important to never set this higher than it should be based on the recommended procedure the manufacturer provides. If you are an advanced user and understand the balance of things, how changes in the signal along the path to the amplifier can affect the resulting output, there are small deviations available to you, depending on your need.

For instance, this is a 500W @2 Ohms RMS rated amplifier and you'd rather not exceed 400W. To know what to do, you have to understand a little bit of math. So earlier I said "What kind of power your amplifier puts out is simply a consequence of the electrical values in the circuit." What this means, is that we know some of the values you are working with, the 8 and 2 Ohms for instance. We also know you want about 400W output.

The chart for amplifier output voltages that JL provides for some of their amplifiers is simply a mathematical summation of all the different Watt output values reverse engineered through using Ohm's Law to determine what you would be seeing in VAC using a multimeter on the speaker output terminals of the amplifier. You can set this voltage higher or lower by adjusting the input sensitivity while playing the necessary specific test tone through the system with your speakers disconnected.

Here is a link to their page regarding this procedure: https://jlaudio.zendesk.com/hc/en-us/articles/204374120-Amplifier-Level-Setting-Guide
There are charts as well as the test files you'd need to perform this procedure on that page.

For instance, I have a HD1200/1 amplifier and I want to set the input sensitivity per the manual, I look at the chart, determine my voltage output and adjust it accordingly while playing the appropriate sine wave, in this case the 50Hz file.



So 69.3VAC would be the setting for 1200W on that amplifier with a 4 Ohm load, which is what I have set up. But how did they get that? Essentially they took the square root of the Watts x Resistance and that gives the value of the desired voltage, so in my case, it's 1200W x 4 Ohms = 4800, which the square root comes to 69.28.

This being the case, if you take your 400W that you want, at 4 Ohms you go 400W x 4 Ohms = 1600, answer is 40 and 400W x 2 Ohms = 800 and the square root brings you to 28.28. At 8 Ohms, to get 400W your output voltage would need to be 56.57. I don't think you'll be able to get that, but you can try and measure what voltage it will put out at max sensitivity and determine what the output wattage would be into 8 Ohms using the same formula.

Obviously these values will not hold exact in the real world because input voltages fluctuate, speaker cabinet parameters vary wildly which affects their performance, and speakers do not hold a steady impedance while in use, it varies considerably so it's really really important to not run out and buy stuff and hope it will all work together when you go to assemble them into a system. Yeah it will make sound, but for how long and how well? That's kind of the art of building these systems.

I recommend that you run what you have at 2 Ohms with an output of 28VAC on the amplifier speaker terminals, set through the procedure JL lays out. Always listen for dips in performance and distortion and turn it down if you have to.

 

Since this seems to be an addition to a factory system, setting the gain at that target level doesn't make much sense. You don't have any other gains to set in this situation, so you simply need to bring the sub level up to match what the rest of the system can do. The sub will be the strongest part of the system and should easily outplay the factory system.

I think this one's a good candidate for a quick & dirty. Start with the gain (sensitivity) all the way to the left. Put on some tracks that you listen to typically at a typical listening volume. Then slowly turn the gain pot to the right until the sub fills in the low end. No need for math here.

 

You're right. Him learning about all of this stuff would be a complete waste of time and totally useless in the future.

 

Nice look'n subwoofer box

 

It’s not a waste of time. Your input and knowledge is greatly appreciated. After listening to the sub on the current settings something is definitely kinda off. Because I’m not a audio aficionado I can’t pinpoint it but after reading your reply’s several times things are piecing together in my head. After I get more experienced with the amp settings I will swap to 2 ohms and do what Dolby tone says. I will start with quick and dirty, at the moment though I am trying to figure out how to tell what the knobs on the amp is pointing at.

 

I will try this!!

 

Far be it from me to discourage any AV education. But why overcomplicate something when simple is all that is needed? I think there's a lesson there too

 

Sounds like you’re Married