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piezo in acoustic style bridge to blend with mag?

Discussion in 'Pickups & Electronics [BG]' started by dlmarquez, Apr 10, 2009.


  1. I have a custom RGW bass, see the photo below: Rod built this as a very fun and interesting project. It has a single Dark Star Magnetic pickup and an LR Baggs AB4 peizo transducer mounted in an acoustic style bridge. We have a Cafe Walter PZP-1 buffer/mixer to do the blending duties. However we (Myself, Rod from RGW, and Walter from Cafe Walter) have never been able to get the 2 pickups to blend properly. We believe we have found the cause and unless Baggs support has some really creative ideas I am going to be having to change to a different piezo.
    I'd appreciate any suggestions on Piezos for the bass that will mount in an acoustic style bridge without huge modifications
    I do not want to switch to a mechanical type bridge (hipshot or Gotoh or???) so I need some ideas and directions in case Baggs can't solve the issue:meh:
     

    Attached Files:

  2. Marcus Willett

    Marcus Willett Supporting Member

    Feb 8, 2005
    Palm Bay, FL
    Endorsing Artist: Bag End - Dean Markley - Thunderfunk
  3. dave251

    dave251 Wendler Instruments

    Feb 5, 2004
    Lawrence, KS
    The problem with an "active" mixing system between mags and a piezo is that the mags can't have the correct "effect" on the piezo. When mixed passively, the mags act as a "shock absorber" to the spikey attack transient response that a piezo produces....the MagPi passive system not only reduces the out of whack transient from the piezo, but also introduces a phase response that more aligns with the "analog" response our ear wants to hear. The result is a much more natural tonality, and probably more importantly, touch response.
     
  4. SGD Lutherie

    SGD Lutherie Banned Commercial User

    Aug 21, 2008
    Bloomfield, NJ
    Owner, SGD Music Products
    And meanwhile the piezo loads the crap out of the magnetic pickup, and there goes your tone from the mag!

    The problem with piezo transducers is they are listening to the string at a location where people don't normally stick their ear. It's not the response you would get if you were listening to the sound from a flat top acoustic instrument, because there is no top! Also the piezo is picking up both the up/down as well as the side to side motion of the string, while an acoustic's sound board will only do the up/down motion.

    So while piezo bridges don't sound bad, they don't sound like acoustic instruments, because they aren't. The real solution is to redesign the pickup system, such as on the NS Double bass, or use some type of electronic realignment of the sound, like in the D/TAR system.

    Piezo pickups are so high impedance they should never be used passively unless you like a clacky scratchy tone.

    Back to the original post..what's going on when you try and mix the two signals? Are they out of phase?
     
  5. Marcus Willett

    Marcus Willett Supporting Member

    Feb 8, 2005
    Palm Bay, FL
    Endorsing Artist: Bag End - Dean Markley - Thunderfunk
    This is not the case with my Wendler...not remotely.
     
  6. SGD Lutherie

    SGD Lutherie Banned Commercial User

    Aug 21, 2008
    Bloomfield, NJ
    Owner, SGD Music Products
    You are hearing a composite of the two pickups, not really both pickups blended. It's not bad sounding, but it's not the same thing either IMO.

    Physics dictates that the piezo will load down the magnetic pickup and remove much of its top end, but of course that will be replaced by the piezo.

    it still sounds like a piezo system to me.
     
  7. Marcus Willett

    Marcus Willett Supporting Member

    Feb 8, 2005
    Palm Bay, FL
    Endorsing Artist: Bag End - Dean Markley - Thunderfunk
    Well, I'm not equipped to argue the physics of the system, but it sounds far more organic, warm and woody than any peizo equipped system I have heard...and I've heard quite a few. I don't claim to know why it works, only that it does and it is invariably complimented on that fact every time I use it.

    As long as it results in a good tone (and in the case of Wendler, it does) the particular method used to achieve that end doesn't concern me outside of mere curiosity.
     
  8. SGD Lutherie

    SGD Lutherie Banned Commercial User

    Aug 21, 2008
    Bloomfield, NJ
    Owner, SGD Music Products
    Yes, it would sound warmer and woodier. I like Wendler's instruments and I think it's a clever idea. And they do sound good. But it depends on the tone someone is looking for.

    I was just pointing out that you wont hear the real tone of the magnetic pickup in a system like that, and that might matter to someone. So the Darkstar in the above bass wont sound quite the same when mixed with the piezo.

    I just think there are other ways to EQ the piezo then using a passive magnetic pickup to do it.
     
  9. dave251

    dave251 Wendler Instruments

    Feb 5, 2004
    Lawrence, KS
    David...The inductance of the magnetic pickup influences the piezo to the extent that the out of proportion attack transient from the piezo( ie, you hear the high frequecies being over emphasized during the attack, since the piezo acts much like a cap in series with the signal)....and if you don't want the piezo to LOAD the mag, you wire it in a series parallel configuration referencing both pickups in the circuit. Two pots, two pickups, and an output jack. THAT'S IT. Play one of my instruments and perhaps you'll begin to understand what the design does achieve.

    In addition, I don't use the traditional UST; the piezo is oriented to pick up as much sound from the solid, carved, western red cedar body as it does from the strings. So in this regard...you are absolutely correct. The location, rather, the proportion of the signal the piezo derives from the string/saddle interface and the resonance from the body itself is indeed a major contributor to overall sound.
     
  10. dave251

    dave251 Wendler Instruments

    Feb 5, 2004
    Lawrence, KS
    Using eq doesn't solve the problem of a nasty sounding piezo...rather, the problem is fixed through the use of a passive mix which emphasizes the phase relationship between the two disparate signals.

    And frankly, I don't care about the mag sound by itself, although a piezo "lockout" would take care of that....a simple $10 switch.

    My theory is if you try to build too much "adjustability" into a product, you end up with a design that has no character at all. That's just me though.....;)
     
  11. Marcus Willett

    Marcus Willett Supporting Member

    Feb 8, 2005
    Palm Bay, FL
    Endorsing Artist: Bag End - Dean Markley - Thunderfunk
    That's a legitimate point. Like anything I guess it depends on what it is you are trying to achieve. My impression with Wendler is that he is developing his own unique system with its' own unique (and I would submit great) sound...but this may or may not be what a particular individual wants.
     
  12. SGD Lutherie

    SGD Lutherie Banned Commercial User

    Aug 21, 2008
    Bloomfield, NJ
    Owner, SGD Music Products
    I agree 100%. There's nothing worst sounding than a raw UST piezo signal!

    Also your system is quite different from the UST on the bass above. I'm not so sure putting an UST on a solid body is the best thing to do. (I'm assuming it's solid). There's no acoustic buffering going on.

    But in this case he's trying to actively blend the two pickups.

    Sorry if I sounded negative!
     
  13. Koeda

    Koeda Supporting Member

    Aug 21, 2007
    Nashville
    I don't think there is much dif in any piezo as far as the signal you get from it - be it undersaddle or Ghost. I don't remember the deets on the Walter circuit, but I am using a Bartolini MPB2-918 on my Jazz and that does the job well. Am using Ghost saddle and Bart Classics in the bass. Comes with a blend pot and trim pots to adjust for signal strength of each pickup. Brian has them at Best Bass Gear.
    David
     
  14. I (with a great deal of help from 4 excellent gentlemen) finally found out what the problem is...thanks also very much to LR Baggs tech support.
    It seems that the Baggs AB4 integrated bridge saddle/piezo is actually 4 piezo elements, and LR Baggs intentionally rotates one of the piezos to be 180 degrees out of phase with the other three.
    this is done for noise cancellation purposes. The good folks at Baggs told me that the AB4 was never intended to be mixed or blended with another pickup.
    So that is the story with that!
    Thanks very much to Rick, Rod, Walter and Anthony!!!!

    As for piezo tones...running my piezo only with elixir RW strings into a dtar equinox parametric preamplifier then into my trusty ampeg b15 head driving a vintage blue B12 cabinet with a weber (damned hard to get all these specifics down) will reward me with an incredibly woody and acoustic sound. particularly if I pay lots of attention to my right hand technique and placement. the piezo is a very demanding pickup but it seems to reward with an amazing array of tones available with changes in attack, hand placement, plucking angle, etc.
    A lot of the discussion above is way over my head, but I know what I like when I hear it.
    Thanks all for your contributions. I have learned quite a bit from this thread
     

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