I found a few videos which i thought could be helpful for some users, im sure there are plenty more videos out there so feel free to post some more into this thread.

Basic speaker parts

How to ground your amp

Bass boost demonstration

Cross over basics (HP vs. LP)

How to build a box

How to carpet a box

Gain setting

Building a kick panel

Series vs. parrallel

Big 3 upgrade

Installing ring terminals

How NOT to wire your speakers

How to make custom RCA cables

Installing component speakers

Mechancal vs. thermal power handling

very nice dude, thanks,

Anyone have links to other vids?

Interesing vids I watched most of them

In regards to the "gain setting" vid, they run a test tone at 50Hz and then use a multimeter to check the voltage output. They start off at about 14V and they want to get it to 40V. They then turn the gain up til they reach 40V.

My question is - Why 40V??

The speaker that they will be hooking in up to is a 4ohm speaker (hence the 4ohm resistor that they use). The speaker would have a power handling at around 400W. Using the rule to determine power (P=V^2/R) they determine what voltage they need from the amps output.

400/4=V^2

V=sqrt(400/4)
V=40

Ahhh ok

So, if i have a monoblock that can put out 1800wrms and that is powering 2 subs that present a 1 Ohm load...

V = sqrt(1800/1)
V = 42.42

Found a cool tool:

http://www.sengpielaudio.com/calculator-ohm.htm

Yes thats correct, but you may not need all the amps power (1800W in your case), the amps output current should depend on the power handling on your subs, and how they are wired. So as your subs have a power handling of 600 watt each, then giving it the full 1800 could cause some damage to them. Best option would be to have an output of 34.64V from your amp as it will then be producing 1200W.

Yep, good point. Altho, RF subs like taking a bit of a beating

Also, there was a slight error in your calculations.

It should be V = sqrt (P x R), instead of sqrt(P/R). You still had the V figure right tho

Just watched the one on carpeting a box, quite a good video.

for anyone watching the 'carpetting a box' one, presuming they are using a contact adhesive (which looks like they are), doing it the way they are is actually quite wrong. contact adhesive needs to dry before it becomes usable, sticking the wet adhesive together ends up with a poor adhesion, which will come apart in the long run.