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Do I need a DI? / What Kind?

Discussion in 'Amps, Mics & Pickups [DB]' started by Akashamitra, Dec 16, 2013.

  1. Akashamitra


    Dec 16, 2013
    Hi Folks,
    sorry if this sounds daft - I'm a software based musician and am new to all this. I bought a dB a couple of weeks ago with a realist pickup fitted. Lovely sound acoustically.
    I want to plug the bass straight into my studio set up (into mixer then into soundcard then into computer). Currently when I do that the signal is almost non existent ie very very quiet and weak. I think the pickup is fine as we tested it with an amp when I bought it.
    I'm guessing I need some kind of DI box? But I don't know where to start - does it need to be passive or active? Can anyone recommend an entry level DI box to use with double bass?
    Excuse my ignorance on this matter - any advice gratefully received.
  2. I haven't used the realist pickup, but it's a little surprising that it wouldn't have enough level for a mixer as long as it was plugged into an input expecting mic level signal. So, there may just be a problem with your adjustments to the mixer. Someone more familiar with the pickup may be able to clarify about it.

    As far as DI boxes (in case you actually do need one), they are all "active." Their usual purpose is to take an unbalanced two wire signal, raise the level of the signal (if necessary), and convert it to a balanced signal which can travel a much longer distance without picking up nearly as much extra noise. Most are able to run on either an internal 9v battery, or phantom power supplied by the mixer. There are cheaper ones available, but sort of the industry standard is the Countryman. It's quiet, simple, reliable, and pretty much indestructible. It's the only one I use, but I know there are other options out there.

    If you are running a very short distance into a mixer, you may well not need one, but there will still probably be times in the future where you will need it at other performance places.

    Edit: Okay, I looked up the pickup. You should actually be getting plenty of signal level for a mixer BUT it's an ultra-high impedance piezo pickup, so it's not going to sound right going right into a mixer. Most people apparently use a bass preamp that has a 1 Mega ohm (ultra-high impedance) input between the Realist and a mixer, or a bass amp. The Realist site says it has 10 "mg" impedance, which would be 10 milligrams, but, since that makes no sense, I'm guessing they've just used a very odd abbreviation for "Mega." ;)
  3. drurb

    drurb Oracle, Ancient Order of Rass Hattur; Mem. #1, EPC

    Apr 17, 2004
    While I'd sure choose an active DI box, they are not all active. For example, look here. Here's a useful summary.
  4. My apologies, I've only dealt with actives in my work. Passives cannot do some of the things we need them for in our theatre.

    This is another nice comparison description. It specifically recommends actives for piezos like the Realist:
  5. run it through a clean mic preamp, roll off some of that bottom end, use a little over 2:1 compression ratio with fast attack and slow release, you should be good.
    Run the signal through anything that says Manley on it.
  6. drurb

    drurb Oracle, Ancient Order of Rass Hattur; Mem. #1, EPC

    Apr 17, 2004
    Given that the sonic characteristics of the DB are very much related to the attack/decay envelope, I tend to abhor compression of any kind. The Realist, like many other piezo pickups (except for the Ehrlund), do a poor job of reproducing that envelope. Because of their location on the instrument, they tend to compress the envelope compared to what would be transduced by a microphone or by the Ehrlund mounted on the table, or what is experience acoustically by a listener. All the more reason to avoid compression with the Realist-- unless, for some reason, it is absolutely necessary.
  7. 10cc


    Oct 28, 2013
    If I was you I'd buy a radial jdi . You can find them used for as little as $125 and for acoustic instruments they sound very good. It is a passive DI with a Jensen transformer in it. They make a bunch more that I'm sure are better but I love mine. If your ever looking for one with stereo radial makes a duplex with the Jensen as well, this is cool when working with keyboards.
  8. bkbirge


    Jun 25, 2000
    Houston, TX
    Endorsing Artist: Steak n Shake
    Radial makes a DI specifically for the needs of piezo pickups. It'll convert the signal from high impedance to low impedance which is what your mic pre on your laptop needs.
  9. Either use a DI box with a high input impedance (at least 1 MegOhms) or get a preamp or impedance buffer (with at least 1 MegOhms, better 10 MegOhms) input impedance.
    Then you can use the output of it into the line input of your mixer or put any kind of DI box AFTER the preamp/buffer.
    So the line is either
    pickup -> preamp/buffer -> mixer line input or
    pickup -> high input impedance DI box -> mixer mic input or
    pickup -> preamp/buffer -> DI-box -> mixer mic input
  10. Don Sibley

    Don Sibley

    Jun 27, 2005
    Fort Worth, TX
    Or skip the pickup and just use a mic. You'll get a phenomenally better sound. Direct piezo is about the worst thing you can record.
  11. M0ses


    Sep 11, 2009
    Los Angeles
    Also, your soundcard sucks. They all do. I don't know of any in-computer card that can come close to sounding like a studio. You're not going to get anything above "meh" sound, no matter how good your bass, your microphone, your preamps, your DI, without a box that has a REAL A/D converter in it. There's a reason people still love analogue recording: cheap A/D sounds bad.
  12. My card's an M-Audio Delta 66.

    What's yours?
  13. Maybe look into a Fishman Pro EQ Platinum II. DI and a preamp all in one made for piezo type pickups.
  14. The Fishman peramps all colour the sound (even with neutral EQ settings).
    Get a FDeck HPFpre series I or II. Cheaper and you can dial out infrasonic mud that happens with piezo pickups. You can shape the sound with an analog mixer or software mixer after recording it.

    If you only record the single instrument at a time, a condenser microphone is the best you can use. Either on a stand in front of the top (if you don't move) or in foam in the bridge or between top and tailpiece. (With a small diaphragm condenser microphone you might also want to try the rubber band mounting through the afterlengths like described somewhere here on talkbass.)
    But since it is not th natural sound of the bass a few meters from the instrument, dial out some bass around 70 to 100 Hz, even when using a microphone. And don't place the mircophone close to the f-holes. The low air resonance is too large there compared to the dissipation of the higher frequencies.
  15. Akashamitra


    Dec 16, 2013
    thanks very much for your help everyone - much appreciated!
  16. drurb

    drurb Oracle, Ancient Order of Rass Hattur; Mem. #1, EPC

    Apr 17, 2004
    Well, not all. Look here.