Amp Setup

[3340TH]

Hi just wondering what all the the features on a amplifier mean...i understand Low Pass and High Pass but Crossover and Gain?

I have (what i believe) a 400w RMS Alpine amp, and running 2 x Apline type R 12" subs....

Also are these subs just single coil, as i don't feel i am getting enough bass out of these subs as i have been in a car with a cheap stereo setup and were pumping a lot harder (at least 3 x times more)

note : The rca are connected from 2 cables into Y adapters that is why it is 1/3 2/4

[3340TH]

anyone??

I'm guessing that the sub is only single coil because it doesnt have the 4 ports at the bottom of the sub, but when researching the sub its says they are dual coil....

I know gain pumps more power into the sub, but what is safe?? and crossover; someone told me it should be set around 50hz...is this right, if this is where it should be set where would you use 200hz/400hz??

Thank you!

Edited September 16, 2008 by 3340TH

[DRD-00F]

single voice coil

gain is amperage (volume)

crossover is what hz the amp will allow through to be played. 50hz is a little low for a 12, if you can, go about 80 to 120 or so.

The safe gain level can be found by clipping. Clipping is the maximum the sub will put out, it is bad for it and if you never hit it then that's good... if you do, you will hear a distorted noise, like a piece of paper in a fan (hard to describe, but you'll notice)

What kind of car were you in with the other sound system? Each car sounds different, and a 33 skyline is especially bad for sub acoustics as the sub sits in the boot, cut off from your ear, and there is a battery, some other shit, a plate of steel then a seat it has to get through before it gets to you...

[3340TH]

it was a mazda 3, ive heard the clipping b4 as i had swapped amps over and the other was making that noise with one sub with higher volume, so swapped them back, so the amp that was popping over the bridged channel is on the speakers now, but am noticing a static noise in the front (not sure about the back) speakers. Subs are working fine though, just not as loud as i wanted...

So what would be good hz for 6" splits and componets?

cheers

Edited September 16, 2008 by 3340TH

[SLY-25T]

i guess ill just give you an example of how mine is set up.

oh and +1 with doof for everythign he said. lol

ive got a 15 inch sub in the boot of my 33. my amp for the sub is set at half gain (i think thats the safest setting if you dont really know what the sub can handle) and the Hz i just set it at near 80 on amp and put the closest setting to that on my head unit. not ure if thats wat ur meant to do but it works for me.

but i guess all subs and amp set ups have diff combinations. i just turn the stereo up to a bit over where i like to listen to it every day, change the Hz to where the sub sounds good and turn the gain up to where it sounds good.

give it a try but dont push the system too far or u will stuff it

[DRD-00F]

I personally put the gain on the amp up fairly high and controll it from the touch screen, but I trust my digital crossover signal from the headunit more then the amp, the crossover on the amp is an extra piece of safety... I probably shouldn't

Also, the boxes are a major part in how a sub sounds, don't under-rate them...

As for your splits and components, they will need a tune, fiddling with them til you're happy with the sound. The best piece of advice I can give is to overlap the frequencies a little bit. If the sub is cut off at 100, cut off 80 or so hz from the speakers. The sub will do that and you will hear better sound from your other speakers and they will last longer...

[mikel]

I personally put the gain on the amp up fairly high and controll it from the touch screen, but I trust my digital crossover signal from the headunit more then the amp, the crossover on the amp is an extra piece of safety... I probably shouldn't

Also, the boxes are a major part in how a sub sounds, don't under-rate them...

As for your splits and components, they will need a tune, fiddling with them til you're happy with the sound. The best piece of advice I can give is to overlap the frequencies a little bit. If the sub is cut off at 100, cut off 80 or so hz from the speakers. The sub will do that and you will hear better sound from your other speakers and they will last longer...

6" will struggle at 80Hz and more likely to pole at high volumes (ie hit the limit of their excursion). Better to keep the crossover Hz the same on both at 100Hz - the sub will cope with 100Hz better than the 6" will cope with 80Hz.

I agree completely with Doof regarding the importance of the box for subs - especially if ported (ie they have a tube or port allowing air in/out of the box). A badly tuned ported box can sound very ordinary.

Ideally you should set the gain on individual amps so that a reference signal (such as a test CD with a pink noise track) gives the same volume from each amp (ie have only the sub amp turned on, run the test track, and measure the volume on a sound level meter, then do each amp in turn and adjust the gain to the same reading on the sound meter).

This is difficult to do without the sound level meter, as each amp is producing a different frequency range and the ear will have difficulty comparing. I use the Jaycar unit ~ $100.

Given the fact that the sub is in the boot, and the other speakers are in the car, and the car itself provides "gain" at different frequencies, it's very difficult to predict what gain settings you should use to get the smoothest response across the frequency range....

....or just crank up the sub until it's too boomy then back it off a bit

[3340TH]

righto thnx for that i will give it a try, the boxes aren't ported, i have a ported box in my vl for a sony xplod, and it goes a lot harder than both R's together, so im used to more bass Umm i will have to search through my headunit for that other stuff, i had a look but wasn't sure wat most of meant so i haven't touched it.

I was going to make fibreglass sub boxes for these subs, would this be recommended? when you say the box is important, do you's basically just mean thick walls and the cubic measurements on the inside of the box??

[mikel]

righto thnx for that i will give it a try, the boxes aren't ported, i have a ported box in my vl for a sony xplod, and it goes a lot harder than both R's together, so im used to more bass Umm i will have to search through my headunit for that other stuff, i had a look but wasn't sure wat most of meant so i haven't touched it.

I was going to make fibreglass sub boxes for these subs, would this be recommended? when you say the box is important, do you's basically just mean thick walls and the cubic measurements on the inside of the box??

yes - sub boxes need to be strong and the correct size for the speaker/driver. Decent drivers usually come with a spec sheet that will tell you the right size for either a sealed or a ported enclosure. If you're putting 2 drivers in the same box just double the volume, assuming you wire the drivers the same way (recommended). The least risk is to mount the 2 drivers on the same side of the box as close to each other as possible (but try to include a brace to strengthen the box in between the drivers). Getting fancy and mounting the drivers at each end of a box can lead to un-predictable results - could sound great, could sound cr@p. It's the same for mounting the drivers on either side of the boot facing each other, they could add to each other (constructive interference) or cancel each other (destructive interference or "suck out").

You mention it doesn't sound as good as cheaper systems you've heard - they may have been working against each other.

Getting the box size right for a sealed enclosure is not as critical as a ported box