Sub Woofer Bass Guitar Amp Help

[x]

I am new to this design so I need some help. I am a luthier/music enjoyer and I need to kill 2 birds with one amp. I am going to make 3 gainclone amps and 3 speaker systems.2 for normal stereo and one for a subwoofer. The sub woofer system will also be a bass amp for testing the electronics in my bass guitars and effects pedals. Hence the need for clean sound. So first question should I design a active or passive filter for the "music enjoyment" sub woofer amp so as to get some good bottom end from my CD's? If so can you direct me to some circuits. How do I bridge left and right channels to get the input. I am a bit limited on electronic theory so I build guitars to make up for that.
Thanks,
Rob
Currently listening to:
El Danse de Moises by Roberto Rodriguez

[newmz]

So first question should I design a active or passive filter for the "music enjoyment" sub woofer amp so as to get some good bottom end from my CD's?

Though this depends on lots of things (i.e. you will need to provide a lot more information), personally I would almost always say an active crossover is a better solution, especially when you are talking about a sub low-pass filter.

You seem to say you are a bit of an electronics noob, but it isn't necessarily that difficult if you get good instructions, etc. One place you definitely do get that is ESP if you buy one of the pcb's for his projects. He specifically asks that people link to the front end of his website rather than individual projects but just follow the links to the projects pages. There's an excellent 4th order linkwitz/riley crossover, I've built one myself and it's great and not really difficult. He also has other related stuff; a +/-15v power supply for opamp based projects like pre-amps, crossover, etc, equalisers, power amps and all kinds of stuff. He also has articles which are really informative. There are two on bi-amping (use of active crossovers), one on active verses passive crossovers and lots of other relevant stuff.

When you are designing a passive for a sub, and therefore the crossover frequency is very low, the large value inductors necessary are the biggest problem. you usually have to go for ferrite cored rather than air cored inductor coil and then you introduce distortion and high series resistance (which means significant power loss).

How do I bridge left and right channels to get the input

I think maybe you mean producing a mono channel for the sub from the two stereo channels from your audio source? this isn't actually bridging, it's called summing. One of the esp projects describes this - project 71 the linkwitz transform equaliser. Fig 1 of the article is a summing mixer and a phase ajdustment.

Bridging generally refers to using two amps to drive one speaker driver and get nearly 4 times the power of one of the two amps.