Gain Staging for DI Bass

Nola

Nola

Well-known member
Can a pro here tell me how they gain stage DI bass guitar?

I have my preamp (it's a pretty good one/single channel) at +25db gain, headphones at like 12 o'clock on volume, DAW at -18db. This seems pretty good, but the wave form in the daw looks abnormally tiny. When I turn up the preamp gain the wave looks like a better size, but I hear noise.

Can you tell me if I'm doing something wrong, or do the figures I'm using seem about right? I was trying to balance noise and signal, but the wave looks so small it has me thinking I might be doing it wrong.
 
Yeah, Nola. It would help to know your setup and your signal chain. I take it you mean the input gain is reading -18dB, which seems on the low side unless you're getting volume spikes. I know some don't like doing it, but I put a hardware compressor in my chain going in. It fattens up the bass and I never need to compress the track in mixing.
 
ashcat_lt said:
How are you connecting the bass to the preamp and what does "daw at -18db" mean?
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Sorry, the channel I'm recording to in the daw is -18db. That's what I meant.

The bass is connected with a short (3ft) unbalanced instrument cable plugged DI into the preamp. I use the hi-z setting with the proper impedance.

So on the preamp, it goes to +70db gain. I use +25. If I go any higher, I get noise (high frequency noise/buzzy). But at +25db, the wave in the daw looks tiny, like it's not enough signal.
 
Get a longer cable for starters. You must be pretty close to your computer, monitor, speakers. Those can create noise coming through the pickups of your bass. Moving a few feet farther back may help a lot.
 
hm, yeah i tried a long cable first.

it sounds good with pretty low noise at +25db. i guess what's freaking me out is the wave form looks small in the daw.
 
Are you plugging straight into the preamp or are you using a DI box? DI boxes can cut out any ground hum and some feedback, so that may help you.
 
That's an option. If you want to go fancy, you could get something like the Sansamp Bass DI. All my bass comes out of the DI of my Gallien-Krueger head. You could pick up something like an MB200 used for not too much money. Cool thing about those Class D heads is you can run them without a speaker load.
 
Chaos351 said:
Are you plugging straight into the preamp or are you using a DI box? DI boxes can cut out any ground hum and some feedback, so that may help you.
Click to expand...

It's straight into the preamp, but it has a DI built in, and it's known to be a good one according to reviews at least.

I guess I'm wondering how much noise is normal. Should it be completely silent? I don't have a lot of noise, but there's a little when I turn up the preamp gain. If anyone is bored and wants to record their bass DI signal just plugged into a preamp that would be awesome. Maybe I'm being OCD or something about a non issue.
 
If your bass pickups are single coil, then they're going to have at least a little hum to them. There are "noiseless" single coil pickup designs, and even humbuckers aren't totally immune to environmental interference (hold your cell phone against the pickup for an example of a worst-case scenario). So yeah, a little bit of hum is normal. Compared to the strength of the signal when you're playing, it should be totally washed out and not noticeable.

If the noise/hum/hiss is too annoying for you, then I guess the troubleshooting would start with figuring out where the noise is being introduced. If you plug nothing into the interface's input and crank up the preamp gain, do you hear noise? Or is the noise audible only when the bass is plugged in?

I'd definitely head to your local music shop and pick up an 18' or 20' shielded instrument cable. Might as well give yourself a little room to move about. a 3' cable is pretty restrictive, and as was mentioned above, it keeps you awfully close to several EMI emitting devices like your computer's power supply, your computer's monitor, and even the power cables that power your interface/computer/monitor/etc.
 
Tadpui said:
If you plug nothing into the interface's input and crank up the preamp gain, do you hear noise? Or is the noise audible only when the bass is plugged in?
Click to expand...

When i do that it's quieter than a mouse. When I plug in the xlr to 1/4 cable from the preamp into my converter, there is a hiss that sounds in the upper mid range. I only hear that when I crank my converter's monitoring (i.e. the headphone amp). When I lower that, I hear almost no hiss. Is this normal? I made the cable myself, so I wondered if I did something wrong, but I just tested it with a multi meter and it checks out fine.

I did tinker with levels tonight looking for a better signal to noise ratio, and I found a setting I'm pretty happy with. But now I'm worried that something is wrong with this cable I made..hmm. Is it normal for there to be a hiss in this setup:

1. Preamp cranked
2. XLR to 1/4 balanced cable going into the converter
3. Headphone monitor on the converter cranked = a lot of hiss, but when I lower the headphone amp almost no hiss.

Thanks!
 
Did you check the battery in the bass?

If you have both the preamp and the headphone output all the way up, I would expect noise.
 
Just reading through this, I want to clarify. You said that "The bass is connected with a short (3ft) unbalanced instrument cable plugged DI into the preamp. I use the hi-z setting with the proper impeda"

The bass is plaugged into the DI, the DI is plugged into the preamp using an XLR to jack plug? If thats the case why? The DI should be plugged into the pre with an XLR to XLR. The proper impedance from a DI output is the Mic impedance, the Di input is the proper HZ input for the bass. This is why your gain structure is all over the place.

Alan.
 
witzendoz said:
Just reading through this, I want to clarify. You said that "The bass is connected with a short (3ft) unbalanced instrument cable plugged DI into the preamp. I use the hi-z setting with the proper impeda"

The bass is plaugged into the DI, the DI is plugged into the preamp using an XLR to jack plug? If thats the case why? The DI should be plugged into the pre with an XLR to XLR. The proper impedance from a DI output is the Mic impedance, the Di input is the proper HZ input for the bass. This is why your gain structure is all over the place.

Alan.
Click to expand...

I read this as "bass is plugged in to the AI with that input set at instrument level". As opposed to line level. I may be reading between the lines, but that's what I figured from his post.
 
I'm not sure now either. Active bass? Passive? Preamp in the bass? External preamp? Preamp part of the interface?

You may need to give us a schematic Nola.
 
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