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1x15 Cab Re-Build

Discussion in 'Amps and Cabs [BG]' started by jtrom, Jan 4, 2016.


  1. jtrom

    jtrom

    Nov 22, 2008
    Kelowna BC
    Over the last week I took the liberty to rebuild my bass cabinet. I have used the same bass cab for about 10 years now and it was in dire need of some fixing up! The original cab was from a 1x15 Fender combo. I took out the head and nailed a piece of plywood for a new top. I gigged that for a lonnnng time.

    My uncle has an awesome shop set up with Festool gear and boy was it fun to build!

    I basically took out the speaker and the hardware. I used 1/2" Birch plywood and a 3/4" face (for where the speaker is mounted). All I did was copy the internal dimensions and build a box to suit. This bad boy is fastened together with dominos and wood glue. This thing is bang on square and friction fit. There was no need to brace anything. It is solid! The original cab had a large vent on the bottom, which I haven't cut out yet. I'm going to gig with it a bit and see if I need to cut anything out.

    The first photo is my old cab haha, which weighs more than my new one and the speaker.

    :)

    IMG_3564.JPG IMG_3560.JPG IMG_3561.JPG IMG_3562.JPG IMG_3571.JPG IMG_3573.JPG IMG_3575.JPG IMG_3576.JPG IMG_3577.JPG [/ATTACH]] IMG_3578.JPG
     

    Attached Files:

    Old Garage-Bander and andruca like this.
  2. Oren Hudson

    Oren Hudson

    Dec 25, 2007
    Gastonia, NC
    That is some seriously good work. Tell us about the sound when you get to use it.
     
  3. Very nice project. The finished cab is so much nicer looking and lighter too. Did you use anything for damping inside the box?
     
  4. You need to ensure that not only do you duplicate the cabs internal volume, but it's porting as well.

    Anything less is nothing more then a crapshoot.
     
  5. normally you're right, but it looks like this cabinet was sealed, and it sounds like they made it to imitate the old cab's internal volume. On the whole I really dig the vibe coming from that cab!
     
    Last edited: Jan 5, 2016
  6. This line in the OP sounds like it had a shelf port, could be wrong though.

     
  7. Ahh, good eye, I just took a quick look at the photograph, the first one is from the old combo, and didn't really see it, but on a second look, you're right - and he also mentions the shelf port too. That should definitely be copied into the new cabinet.
     
  8. jtrom

    jtrom

    Nov 22, 2008
    Kelowna BC
    No I didn't dampen anything. I'm not sure, exactly, how or what that would look like... I can alway pop it open and add stuff later.

    Do you have any suggestions for damping the box?
     
  9. jtrom

    jtrom

    Nov 22, 2008
    Kelowna BC
    I was planning on cutting some holes for the venting/porting. I wanted to see what it sounded like without any ports... at the moment it sounds pretty similar, but that's just me practicing in my room. I'm sure once I'm on a stage at stage volume there might be a noticeable difference.

    In all honesty, it doesn't look like the original cab makers put a whole lot of thought into making the original cab a "sonic masterpiece" so i'm going to play around and see what sounds best.
     
  10. I have used un-backed fiberglas insulation, it works but a lot of people prefer other things that don't cause you to itch after handling. There are many ways to go about this and I'm not an expert. If you are interested I suggest the search key as there is a multitude of discussion on the subject.
     
    jtrom likes this.
  11. Turnaround

    Turnaround Commercial User

    May 6, 2004
    Toronto Canada
    Independent Instrument Technician, and Contractor to Club Bass and Guitar - Toronto
    Most often the bracing in a cabinet has nothing to do with the strength of the cabinet, but is there to keep the panels from vibrating, causing uneven response in the cab's performance. So you might want to consider some internal bracing.

    Also, the ports were there to control the resonant frequency of the system, so you won't get the same frequency response without them. That's not to say that you won't like it without a port, but it's behaviour will be different. I used to design and build custom speaker systems, so I do know about these things.
     
  12. jtrom

    jtrom

    Nov 22, 2008
    Kelowna BC
    Thanks for the tip! It's my first build so I'm wanting to get as much info as I can.
    Considering the design of the cab do you have any suggestions for a bracing technique? Also, would it make a huge difference if the port wasn't the same size? I'm considering drilling holes instead of having a huge rectangle cut out of the bottom. If I'm covering the same amount of square inches in the holes does it really matter? And do they have to be at the bottom?
     
  13. alaskaleftybass

    alaskaleftybass Will Hanbury, Jr. Supporting Member

    Mar 21, 2012
    Sitka, Alaska
    Nice cab! Love the new finish and the fact that it's lightweight. Please report back after live performance, I'm intrigued. :thumbsup:
     
  14. Turnaround

    Turnaround Commercial User

    May 6, 2004
    Toronto Canada
    Independent Instrument Technician, and Contractor to Club Bass and Guitar - Toronto
    First I would be concerned about the back panel. I would consider a diagonal brace, much like your old cab. The sides may not need any bracing. Pound them with your fist and see if you get a boomy drum effect. If so, you probably need to brace them too.

    You can use multiple holes rather than one slot for the port, as long as the holes aren't too small, and as long as they add up to the correct area. One-inch holes are too small - they are likely to whistle, and won't work as well as larger ones. But it's not clear from the photos if the old cab had a sort of shelf at the port - that's important as it is a component in the tuning of the cabinet. All the dimensions are critical - the volume of the cabinet, and the volume contained in the port section. Together with the resonant frequency of the speaker they determine the low-end frequency response of the system.
     
  15. jtrom

    jtrom

    Nov 22, 2008
    Kelowna BC
    Good point. The idea is not to build and speaker up a cajón! Yes, if there is any booming or resonance from the back and sides I will brace it with something.

    And yes, there was a 2" shelf protruding off the back, top, of the port. I suppose if I were to drill holes I would need to have a 2" "shelf" off of those as well? ... Hmmm. May be easier to just do a rectangular vent...
     
  16. yeah, it would be easiest just to make the 2" shelf port IMO - the length of the port is a part of its design. Have you ever held a bottle to your mouth, and blew across the opening of the bottle and heard a tone? The back end of the speaker (inside of the cabinet), is doing a similar thing to that port as you are to the bottle, except the port is tuned to a specific frequency. This helps to improve its low end capabilities.

    Changing the length, location, and format of the port can change the performance in unpredictable ways if you don't know what you're doing. I'm not saying it's impossible to tune some round ports to the same frequency, or that it would sound different or bad, it's just a lot simpler to mimic the exact shelf that they're using than to try to reinvent the wheel. Of course, logic seems to dictate that the same port area with the same port length would lead to at least a similar tuning in a different format/shape, but I really don't know that one.

    If you can, use a router to get a bit of a radius onto the outside edge of the shelf port on the baffle, this would help reduce chuffing a bit, if it ever was a problem.
     
  17. jtrom

    jtrom

    Nov 22, 2008
    Kelowna BC
    soooo here's the deal: after playing through the cab for an hour or so it's sounding a little woody and boxy. Not ideal.

    So as some of you were saying, i'm going to cut out the vent and 2" shelf and see how that changes the sound.

    THEN, i'm going to go get some insulation, probably extra thick quilting foam, and give it a good layer all around the inside... then I'll have a final consensus as to what it will sound like.

    ps. pretended it was a cajón for a couple minutes and there wasn't any vibrating or anything like that. I may still brace the back though... not sure.

    pps. i'm glad i had the foresight to make the interior of the cabinet easy to access. :thumbsup:;)
     
  18. jtrom

    jtrom

    Nov 22, 2008
    Kelowna BC
    Alright,
    I want to thank you all for your suggestions and feedback! I completed the unit today and just played through it and it sounds nice. I repositioned the speaker hole, used dado joints for bracing, and some insulation. The "woody-ness" is gone and the sound is a lot tighter. Still weighs less than the other empty cab. All said and done it cost me about $70, so I'm very pleased with it for the money.


    IMG_3580.JPG IMG_3581.JPG IMG_3582.JPG IMG_3596.JPG IMG_3597.JPG IMG_3598.JPG
     
    Last edited: Jan 14, 2016
    bearfoot and Bass_Pounder like this.
  19. Primary

    Primary TB Assistant

    Here are some related products that TB members are talking about. Clicking on a product will take you to TB’s partner, Primary, where you can find links to TB discussions about these products.

     
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