DIY cab 2


Senior member
Okay - thanks for the advice!  Next step - roughing a cheap cab without real regard to dimensions or quality, just for practice.  4 old 4 ohm car speakers that I replaced.  I know they will sound like crap, but could I use one or two of them to build a cabinet for practice?  I would be using my 5 watt Epi Valve Junior head to power it.  They say they are rated for 40 watts.  Any reason why they wouldn't work?

I also see 2 cut wires coming out the top of each speaker - do I just solder these to new wires connected to a guitar jack, and connect that to the speaker cable coming from the amp?  Anyone have pics of how this should look?
what is the output on the amp rated for ohms wise?

watts is a real relative term, can be rms can be peak. guitar speakers are very under rated. distortion is very hard on speakers. but being that you have 4 and the amp is only 5 watts i think your good.

do the speakers have paper cones? if the cones are thin and light they may have a decent range on them, might sound a little dark but you might be suprised at how it sounds. car speakers tend to not be a real subwoofer, sometimes not even a woofer. due to cabin gain it's just not nessisary so they might have enough highs to get by.
My amp has a 4,8, and 16 out!  The matching cab has a 16 input only.  I just want to jack around with the car speakers first to see if it is worth my time.  Should I connect to the wires sticking out the top, or should I connect new wire to where those wires connect inside the speaker?  Also, those go straight to the guitar jack?  Thanks!  I will probably just do a panel rather than an entire enclosure to start.
Lets say you have two of those speakers.  Each has two wires on it.  What you wanna do is wire from the jacks "tip" to one side of the first speaker, then the other of that that same speaker to the second speaker, then from the second speaker to the "ring" of the jack.

Two four ohm speakers, in series... result is 8 ohms.  If you use all four speakers, then daisy chain them all together... total of 16ohms.

Use the appropriate inputs.

There is something to watch for.  Speakers are marked with a + sign, or "dot" on one terminal.  That may or may not be consistent with the wire colors there - car speakers being what they are.  Its important to make the marked terminal the "input" terminal.  Think of it as from "tip" to input, then leaving the speaker to the next speaker "input", then back to the "ring" of the jack.

You wont hurt anything, but if you reverse one speaker, it will be out of phase and the whole thing will sound terrible. 

Wattage - at first glance, it appears that a 40w speaker would work on a 5w amp, no?  And two... rated now at 80w would be huge overkill, no?


In fact, those car speakers are not rated in RMS watts, but in some arcane weighted "created to fluff the numbers" rating system.  They call it "music power" or call it "program power"  or "peak" power, or all sorts of things, but its not RMS wattage, which is what your amp is rated in.  Your little 5w head probably wont destroy them, but an amp of a maybe just a bit greater power will.  The speakers probably can handle about 5w RMS each, if that. 

Given all that - the TONE you get will be pretty shrill.  Why?  Because guitar amp speakers have decent low end but max out at about 5000 to 6500 Hz.  Your car speakers sacrifice low end, and will give you extended treble for that "crisp" in program music (bells, snares, cymbals).  But... have fun with 'em.
You know, I run a Marshall plexi clone (Ceriatone) through a 10 inch woofer and the sound is really treably, like the highs are sharp and ice pick like and not much of a low end. Then I switched to a SAMMI 12 inch 100 watt speaker, and now the highs are no longer sharp and the low end is much better... I don't know if its got more to do with size than type of speaker though...