DIY110 practice cab...

Discussion in 'Amps and Cabs [BG]' started by Sundogue, Dec 3, 2007.

  1. Sundogue


    Apr 26, 2001
    Wausau, WI
    I'm going to build two very small 110 cabs using my BP102's, along with one Goldwood GT-1025 tweeter in each cab.

    The BP102's SPL is 92 and the Goldwood tweeters are 90. The BP102's range from 40 to 2000 Hz. The Tweeters go from 1800 to 30,000 Hz.

    From what I gather I can wire the tweeters in parallel with the BP102's without using a crossover, correct? Let me know if not.

    These cabs aren't going to be anything other than very small cabs to take back and forth to practice, or rehearsing on my own...or maybe small, coffee house type gigs.

    I am NOT going to use any other speakers, so please don't waste my thread with suggestions of other speakers, as I already have the BP102's and want to make use of them in some small cab. I also have a limited budget (read; I really don't want to spend anything, except what I absolutely need).

    For my purposes, I just want some opinions on the following...

    Tweets can be wired in parallel with no crossover? Please no reference to website info that reads like SPAM novels. Thanks.

    Would you make a ported or sealed cab with the BP102's? Remember I want these to be SMALL cabs, not necessarily loud, or low.

    If you did port them, would you tune them to 40 Hz (I play a four string), or perhaps 60Hz and get the mid bump?

    Any other info aside from suggestions for other speakers would be greatly appreciated. These are just for basically practice and I'm looking to utilize my existing speakers in something extremely portable, as I already have small, kick ass 115 neos for gigs.

    Mucho thanks.
  2. BassmanPaul

    BassmanPaul Inactive

    If the tweeter you plan to use are piezo you do not need a crossover. If the tweeters are dynamic, ie have a voice coil (read 8 ohms for example) then you do indeed need a crossover rated at the full power of your woofers. Your GT-1025 are indeed piezo and can be wired with out a crossover but you might want to put a 0.1Mfd 400V cap in series with a 20 ohm 10W resister in series with each one.

  3. Sundogue


    Apr 26, 2001
    Wausau, WI
    What do the cap and resistor accomplish? Does it force the tweeter into accepting ONLY frequencies above a select point? It appears (from what I've read) that tweeters do accept some lower frequencies, but at such a minimal amount as to not even be noticeable. Perhaps I'm wrong on that, but it's hard to get through the technobabble.

    Yes, the ones I'm looking at are Piezos.
  4. Nope. No caps in series with piezo tweeters.

    A resistor is OK, especially with any cheap amp that can go into UHF oscillation. 4 ohms, 10~20w or so will do the job just fine. The resistor provides some UHF load to the cheap amp, where the piezo by itself appears as a capacitive load.
  5. Sundogue


    Apr 26, 2001
    Wausau, WI
    What cheap amp are we talking about?

    Is it necessary to use a resistor IN MY CASE?

    I simply want to wire up a small 110 cab with a piezo tweeter. Anything wrong with wiring my BP102 with Goldwood GT-1025 in parallel?
  6. It depends on the amp. Can't tell you which do, which do not have issues. Some of the Parts Express plate amps will self-destruct without a resistor in series with the piezo.

    It is not a big deal... install it and forget about it.
  7. Sundogue


    Apr 26, 2001
    Wausau, WI
    I'll be using my Superfly head (4 ohms per side...and the BP102's are 4 ohm speakers). What the heck is a plate amp? I don't think I would ever buy an amphead from partsexpress anyway. ;)
  8. Geoff St. Germaine

    Geoff St. Germaine Commercial User

    Aug 31, 2001
    Halifax, Canada
    Owner - St. Germaine Guitars

    This is a plate amp.
  9. Sundogue


    Apr 26, 2001
    Wausau, WI
    Thank you. Makes sense for a a subwoofer in a car stereo or home theater.

    I wouldn't use one for practice though.
  10. John123z


    Jul 7, 2006
    Hershey, PA
  11. Sundogue


    Apr 26, 2001
    Wausau, WI
    Yup. In a couple of other threads I posted. I am aware of other cabs. Thanks, but I'm just looking for answers to my specific questions.
  12. Lia_G


    Oct 27, 2005
    Have you messed around with different cab volumes and sealed vs potted in WinISD? I created a couple of projects to compare, and found that by going very small on a sealed cab, around 15 litres, I got a mid-bass hump around 100-200 hz. It looked like it might help volume a bit, as the SPL in that range was up around 94. Max spl, if I remember the chart correctly was about 116 in that frequency range. However, then I realized that 15 liters is a *tiny* cab! Not sure if getting that small is feasible?
    Huge caveat: I am an extreme novice at this, having just started using winisd.

    Good luck, whatever you decide to build!
  13. I'm looking to do the exact same thing, just build a tiny 110 practice cab for my bedroom with an eminence speaker I already have and a piezo tweeter
  14. Sundogue


    Apr 26, 2001
    Wausau, WI
    Yes, I've been playing around with WinISD for this. I just like to hear other's thoughts on it. Sometimes a person relies too much on software and less on their ears, so anyone who's built small 110 cabs might offer up some opinions on what's worked and what hasn't.

    I know I can get that mid bass hump by tuning it a certain way, and BP102's have low sensitivity, so I'm messing around with all kinds of scenarios.
  15. I'm thinking I'll probably just base mine on the size of one of the popular brand's dimensions and hope it comes out ok. I'm not gonna do any serious recording or shows with it or anything, just a bedroom practice setup
  16. Lia_G


    Oct 27, 2005
    Cool. Looking forward to seeing what you come up with!

  17. Bass4LifeRS


    Oct 18, 2005
    Good luck, I'll be following the thread. :)

    (BTW, the Omni 10.5 is "huge", I wish Bill'd design a 1x10 or a 1x8 cab for use as a tiny stage monitor for low-volume gigs just to get some definition in addition to the PA, or as a bedroom speaker.

    Something like a Markbass Micromark or something, without amp but with 1 speakon connector... The MicroBill !)
  18. Sundogue


    Apr 26, 2001
    Wausau, WI
    The Omni 10.5 (110) is only 16" deep by 20" wide and 13" tall. It's half of a full Omni 10. Hard to get any smaller than that. The full Omni 10 is twice as tall...same other dimensions though (which is pretty small for a full 210 cab).

    But if I build a sealed 110, it would be smaller than that. Even a ported front loaded 110 would be quite small. Even at that, it wouldn't be much smaller than an Omni 10.5, and more than likely not as loud as that either.

    But Bill himself says the BP102 isn't the best driver for an Omni and I want to use the speakers I already have.
  19. kraigo


    Jun 21, 2007
    Minneapolis, MN
    I use a Len Moskowitz designed homebrew 1x10. The crossover schematic is here:

    The original design article is here:

    One implementation is here:

    I like my little cab. A friend and I fried the original woofer one afternoon. The woofer is probably no longer available. I couldn't find a direct drop in. What's in there now is a eight ohm (the original woofer was four ohm) woofer from Parts Express.

    It sounds good to me. It's a big box for a small woofer, which I'm sure helps. Plugging the replacement Dayton 10's T/S params into WinISD showed a pretty good modeled curve with that box anyway.

  20. The Eminence S2010 is what you are looking for. It has sufficient range for a practice amp, and can be augmented with a tweeter.

    S2010 runs optimally in 0.94 cubic feet.

    I'm building one for myself. It is 15H x 14.75W x 12D inches with a slot port. F3 is 67 Hz. I figure the weight at 19 pounds with 1/2" baltic birch and the driver. Grille and covering will add a couple more pounds.