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Hi my bass player is in between owning a bass amp and we were thinking of plugging him into the PA system directly while he shops for the right bass amp.

Can this be done direct in, without a di box? I’ll list the mixer and speakers below. What problems could we run into? Would he have to plug into certain channel? Any settings we should consist or avoid?

Mixer: behringer xenyx 802
Speaker: mackie sa1521

Thanks in advance if anybody has any sort of information to help me :)
 

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A DI of some sort would be better than plugging in directly, but plugging in directly should be fine for rehearsal purposes. Most modern boards are fairly forgiving in terms of what signal they see. It may not sound the best, but you are unlikely to do any harm. Try it.
 

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A DI of some sort would be better than plugging in directly, but plugging in directly should be fine for rehearsal purposes. Most modern boards are fairly forgiving in terms of what signal they see. It may not sound the best, but you are unlikely to do any harm. Try it.
Pretty much what I was thinking
If a DI is used it helps, usually
 

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Many (if not most) pro touring bands have done this for years. While we were enjoying the spinning chickens behind Geddy, the FOH and understage monitors were doing the heavy lifting. But they are big, professionally run PA's with lots of bandwidth and power - and bass takes power and speaker excursion.

Smaller systems without dedicated subs would struggle to get the lower octaves and may sacrifice headroom to try and reproduce it. Some mixers have the ability to take instruments in directly (my Mackie Onyx 1602 has specific setting on inputs 1 and 2 for this) but not all mixers do. Direct boxes work better with most mixers unless you are sure you don't need them.

I have a fairly small 120 watt 115 bass amp that I take a line out of to my PA in my house. The PA is 3 way active with a 118 sub so it gets lower (and louder) than the amp will, although 'louder' isn't really necessary in my application. You just have to be careful you don't try to get too much low end extension out of your PA speakers trying to run a lot of bass through them. That is to say, you are probably OK as long as you aren't playing really loud and/or expecting really deep bass.
 

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another vote for the DI, but that mixer only has 2 xlr equipped inputs. If you are running vocal mikes in those channels you won't have a channel to plug the DI into.
 

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Hi my bass player is in between owning a bass amp and we were thinking of plugging him into the PA system directly while he shops for the right bass amp.

Can this be done direct in, without a di box? I’ll list the mixer and speakers below. What problems could we run into? Would he have to plug into certain channel? Any settings we should consist or avoid?

Mixer: behringer xenyx 802
Speaker: mackie sa1521

Thanks in advance if anybody has any sort of information to help me :)
DI Box is a must (assuming a typical Hi Z bass; Lo Z is rare and unlikely). Lots of people do this all the time. Ideally a preamp/DI box so he has some tonal control/options. Chances are he (or someone in the band) has some pedal with a DI out already. The DI needs to plug in to one of tha channels with an XLR input and a mic preamp; other settings are a matter of taste and goals. The one thing I will recommend is since, unlike a mic, there is little risk of feedback or bleed, crank the mic gain and drop the channel fader (opposite of vocal mic pretty much where you want to minimize mic gain to prevent those things). The speaker you listed is a Front of House or main; he's gonna need a monitor to hear himself (unless he stands out front, which is an option if he does not also sing at all).

That said that mixer only has 2 mic inputs - are those already used (vocals etc)? If so a DI box won't help you; you need an actual mic preamp (with built in DI; anything modern will have that) and then plug the output of that into one of the line in channels (3 and up).

Personally I don't recommend it, but a lot of people like it. Better for clean/funcky than dirty riffage. Considering most gigs at a venue (not a DIY sound situation) will do this anyway (your bass amp becomes a glorified monitor) it's not too different or weird (really surprised at the folks saying no go get an amp - guitards ;P); frankly I think it's better to hear what you actually sound like than be fooled into thinking the tone out of your amp is what the audience is hearing.

Someone above suggested renting an amp - that's a good idea to get to know a model you are considering purchasing, but not any old bass amp you're not familiar with for a show. If you ever plan to play a proper venue, the sound guy will DI the bass so may as well get used to it. I have spent the last 10 years trying to convince sound guys not to do that with various degrees of success (push to hard and they just hit the suck button) - the struggle is real. I actually prefer smaller venues where the bass/guitars aren't in the PA at all (just vox and kick) for that reason. Those shows tend to be more fun.
 

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I've done straight to PA from the bass...with low Z active pickups.
Was good enough to make noise at band rehearsal.

But if it's a typical passive pickup Bass, that option won't sound as good.
The 802 doesn't have a High Z input unfortunately, so a DI box is a necessity.

There's tons of them out there, but if money is tight; I'd recommend the Behringer BDI 21. It's a Behringer version of a Sansamp and gets some really smooth sounds, or it can operate as strictly a DI.

$48.00 brand new at L&M, less than 2 pairs of Bass Slinky's

Behringer - V-Tone Bass Amp Modeler/DI Box
 

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As a bass-playing sound guy, plug your bass into a pedal, something that's pretty neutral when it's on. It really doesn't matter much *what* kind of pedal, as long as you can live with the sound. A boost, maybe, a compressor might be best, or an overdrive with the drive turned down.

The big problem is not so much needing a DI, as that the instrument wants to see a pretty high impedance when it's plugged in; ideally 500KOhm, more is probably better. A low-impedance input being fed by a high-impedance output (most non-active instruments, with a few exceptions) will cause the sound to be thin and kinda plasticky. (Conversely, a high-impedance input fed by a low-impedance output tends to sound woofy and lifeless.)

Most pedals tend to be true-bypass or nearly so, so there's little difference between plugging into the pedal when it's off and going into the mixer directly. When the pedal is engaged, though, the instrument sees the pedal as its load, and most pedals try to appear like the front end of an amplifier.
 

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Conversely, a high-impedance input fed by a low-impedance output tends to sound woofy and lifeless.
Not sure what you mean by this, perhaps I am misunderstanding.
The pedal 'buffer' (low impedance) into a high impedance amp input would be the perfect example, it does not sound woofy or lifeless.
As a general rule, you always want to run the source into a higher impedance. 5 times higher is often referred to as a minimum.
 

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Not sure what you mean by this, perhaps I am misunderstanding.
The pedal 'buffer' (low impedance) into a high impedance amp input would be the perfect example, it does not sound woofy or lifeless.
As a general rule, you always want to run the source into a higher impedance. 5 times higher is often referred to as a minimum.
You're absolutely right; as a general rule, 5 times higher is dandy. Ideally, for best and fullest fidelity, you want to run the source into an identical load impedance. And yes, that will vary with amplitude and frequency. And no, impedance is not the same as resistance. And fullest fidelity isn't what one gets running a P Bass into an SVT.
What I should have said was that for musical reproduction, higher is better than lower, to a point. Woofy *is* an overstatement, but a low impedance source into a high impedance input will be darker, less bright sounding. Sometimes the differences need an oscilloscope.
Ever played a Les Paul Personal or Professional) (they're not the same as the Recording)?

Thanks for paying attention, and making me pay attention.
 

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IME, that was what we thought when signal connections on most equipment was transformer balanced @ 600 ohms (input and output). You needed to balance input Z and output Z or else you were screwing with freq response (and levels, which always dropped at least 3dB when terminated compared to not being terminated).

As active electronics became ubiquitous, that mentality went away. Output Z was easy to get very low and terminating it in a much higher input Z made things more predictable. The usual rule of thumb now is (as @jb welder mentioned) at least 5X higher input impedance than output impedance. As long as your output wasn't being overly loaded down (something less than 5X), it would respond as expect.

If you ran that piece of equipment into an open circuit (i.e. input Z = infinity), it would have no artifacts from loading. Running it into something that is 5X, or better yet 10X, higher Z led to about the same result. Being as it was simply a voltage transfer/connection and not a power transfer/connection, there is no voltage drop at that load impedance, either.

Of course, all of this goes away if you are talking about a power connection. But for signal connections, this has been my experience since the early 80s.

Some board do accomodate hi-Z instrument outputs. My Mackie Onyx has two inputs with a Hi-Z setting that terminates basses and piezo acoustic pickups perfectly. But a lot of boards do much better with a direct box in line to terminate things correctly.
 
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