Bass cabinet wattage?

[toejam]

I'll be getting a bass cabinet with 15" speaker that's rated at 300 watts. I've got a THD Univalve head right now (15 watts) going into a Boogie cab with 12" Celestion G12H 70th anniversary 30-watt speaker. The bass cab has two jacks... so if I run the head into that cab and then piggyback from the other jack into the 12" cab, am I correct that I'll need to set the amp for 4ohms? The amp's got a switch for 8/16 or 2/4 ohms.
Also, it seems the bass speaker would be pretty underpowered. Would it be wiser to find a 15" speaker that handles less wattage?

Edit: Both cabs are 8 ohms.

[rjohnstone]

Wattage is not really an issue.
It's the ohms you need to worry about.
Also, a bass speaker is going to be voiced differently than a guitar speaker.
It will tend to be a bit darker sounding.

[toejam]

Sorry, I just edited to add that. The cabs are 8 ohms each.

And darker is cool, as the Uni is a little bright anyway.

[rjohnstone]

Yea... if they are 8 ohms each and you run them in a series (out of one and into another), set the head to 2/4 ohms setting.

[toejam]

Cool. Thanks.

[zeegler]

Hey wait a second. If you run two 8 ohm cabs in series, that equals 16 ohms.

Series = add
Parallel = divide

[rjohnstone]

Shit... yep... you're right.

Sorry Joe... was going off of memory and forgot to take into account for how the jacks were wired.

One thing you will need to check is how the output jack is wired on the bass cab.

[toejam]

Ah, okay. I'll have to check it out. Thanks, guys. I know the Univalve can handle mismatches and all, but I just don't want to mess up the speakers.

[zeegler]

I wouldn't worry too much about the speakers Joe.

[CharvelRocker]

I wouldn't worry too much about the speakers Joe.

Yeah. IN GENERAL, the only thing that can really damage speakers are one of two things; Using them for something they shouldn't be, (IE bass or keyboard into guitar speakers), or putting too much wattage into them. Also, yes they do sound dark, but its an interesting tone, I was actually given a Peavey bass amp with a Sheffield 15" Black Widow in it. I accidentally recreated the scene from back to the future

[toejam]

Cool beans! I did have a Peavey bass combo with 15" speaker that an old friend gave me back in the early '90s. I used to have a crap Gorilla practice amp and would hook them both up with an OD and stereo chorus pedal. It definitely gave my sound some warmth. In the late '90s when I got married and moved, I wound up throwing it away because it was pretty beat up. I want to create Back To The Future now! :ROTF:

[Rsmacker]

IN GENERAL, the only thing that can really damage speakers are one of two things; Using them for something they shouldn't be, (IE bass or keyboard into guitar speakers), or putting too much wattage into them.

The worst thing for ANY speaker, doesn't matter what wattage or what amp you are driving it with, apart from the amplifier delivering a nice DC fault spike up it, is clipping. It's the easiest way to destroy a driver, and is the number one cause of blown speakers (even though no-one ever owns up to clipping the shit out of them).

You can easily wreck a 1Kw driver with a 150w amp by square waving it, though it will sound fucking awful so you'll know you are doing it. Also remember that some speakers NEED to be driven hard to make them sound any good, like the Bose 802 cabinet, 8x 5" ish drivers, total 240w, sounds best driven by something sticking about 600watts up it (NB. 600 CLEAN watts, no clipping)

Your amp will be working hard delivering frequencies to the bass cab that can't be reproduced by the driver, though I think for what you'll be doing with it, it's no great problem.
I used to be in a band with a guitarist who used a 4 x 12 for the "normal" sound you'd expect from the guitar, and also had a 1x15 cab to get the extra "darkness". We used to throw the signal through an active crossover unit and separate power amp so that there was just bottom coming out of where bottom should come out (oo-er!).

I countered that by using a Fender 2 x 15 cabinet, I think from a Dual Showman set-up, loaded with some tasty JBLs, and that did get right up there on the frequencies range, but I have no idea what model they were, or the Thiele Small Parameters. Sounded fucking awesome though.

(Shame about the shit I was playing through it! )

[horns666]

Joe, get a bass cab with a port or glory hole. Stick your pud in there while you spank the bass..it's nice!

[Rsmacker]

And they say that we Brits are filthy bastards who bring the conversation down to base level (bass level?)!

[toejam]

Joe, get a bass cab with a port or glory hole. Stick your pud in there while you spank the bass..it's nice!

LOL It's got two ports!