Is it possible to get a decent sound by plugging a bass directly into a PA system without using a DI box? Could that result in any kind of damage to the speakers?
No, it actually sounds better imo. That's just me though. I love having the bass coming out of all the speakers when we play. It doesn't need to be nearly as loud, and it's feels so much more balanced in the PA
You should always use a DI box for plugging the bass into a PA. You can plug straight in, but it won't sound good, as the mixing desk is expecting a very different impedance load to what a bass or guitar supplies. The DI box matches the impedance to give the desk the load it wants (as well as electrically isolating the bass)

It absolutely won't cause any damage to any part of the PA, unless you do something stupid
Other than using a microphone in front of your amplifier's speakers, I do not see how you could do it. Your bass is a high impedance device, and you need something (like a D.I. Box) to raise the signal to line level for the P.A. Some amplifiers have a "Line Out" feature that is for doing this. But just plugging your bass straight into the mixing board? That one I do not see happening, unless I am missing something in your suggestion.

As suggested, it will not hurt anything, but even if it worked and you could hear your bass, it would sound horrible.
"Maybe this world is another planet's hell?" - Aldous Huxley
You need to match the signal from your bass, to make it balanced. As stated above, you really do need a DI box to 1). shape your sound a bit more and 2). avoid any damage to your PA system. I don't know quite what damage it would do to the PA, but a high impedance signal going in without any balancing sounds dangerous to me, especially to your speakers.

My old band used to do this, because like most bands, we were entirely self funded and paid for a small PA, in the hopes that it would double as an amplifier for both bass and vocals. The bass never sounded quite right through it, and was a nightmare at rehearsals and gigs for sound balancing. Sounds good on your own, if you have massive subwoofers, but in a band lineup, especially with vocals amplified with the same device, you'll have problems.

Buy a DI box, or a generously sized amp with the option of a lineout feature - it'll be best in the long run.
A DI box and a little compression gives the best results for us. Without these the impedance mismatch makes the instrument sound odd.
"Your sound is in your hands as much as anything. It's the way you pick, and the way you hold the guitar, more than it is the amp or the guitar you use." -- Stevie Ray Vaughan

"Anybody can play. The note is only 20 percent. The attitude of the motherfucker who plays it is 80 percent." -- Miles Davis

Guthrie on tone: https://www.youtube.com/watch?v=zmohdG9lLqY
It works just fine going bass>mixer. Like was said you loose a bit of your tone shaping, but it will not damage anything at all.

I have been gigging and running sound for 15+ years and I have never seen any time that doing that breaks/ruins any part of a PA

But a cheap DI box is $20ish for a passive ART DI box. I have 3 of them just in case someone needs them. This is the one I have www.musiciansfriend.com/pro-audio/art-artcessories-zdirect-professional-passive-direct-box
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Quote by telemaster16
Is it possible to get a decent sound by plugging a bass directly into a PA system without using a DI box? Could that result in any kind of damage to the speakers?

Depends upon the speakers. Top quality PA speakers should be specced to cover the whole frequency range but budget models often have drivers which are limited in excursion and could be damaged by the demands of bass, unless you filter the lowest frequencies. Email the manufacturer to ask.

Using a DI box rather than the high impedance line jack on the mixer won't have any real significance in whether the speakers can handle bass. You may not have enough gain to achieve full output and there may be some minor frequency response changes due to impedance mismatches, though probably none. A long unbalanced lead into the PA may cause hum and noise problems and as a decent DI is only the cost of a decent lead why not save up for one?

If you are just starting up and money is tight then you'll probably be OK in the rehearsal room but keep the volume sensible, cut the bass a little and don't try boosting it or money will get a little tighter when you have to replace those cheapy PA speakers!
Last edited by Phil Starr at Aug 3, 2014,
I started out using a Bass Pod XT (used about $80) into an existing power amp (an HD1500 Carvin) into a pair of Carvin LS1503s (PA type cab with a 15" woofer, 6" mids and 1" tweeter). The HD 1500 weighs 9 lbs, runs about $299 new (mine was used and about half that) and puts out 800W into a single LS1503, 1500W into two. The LS1503s are $269 each, new.

It was an easy transition to simply run the Bass Pod XT direct into a PA mixer.