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HELP 210+115 bass enclosure problem. Maybe over-excursion?

Discussion in 'Amps and Cabs [BG]' started by TijlT, Jan 20, 2018.

  1. TijlT


    Jan 20, 2018

    My name is Tijl. I'll probably need some engineers to help me out.
    I make cabs occasionally. Mostly guitar cabs which I found quit simple.
    As for bas cabs I made 2 great sounding cabs before. But now, my 3th bass cab is giving me some troubles.

    The problem:
    It is most common with the 2x10" speakers. It sounds like over-excursion. Or.. it actually sounds as the voice coil is hitting the magnet (or any part behind the voice coil).
    The cab itself actually sounds amazing! It is a true pleasure to hear it at lower volume or with a normal electric guitar. I tested the cab with my Orange CR120H (transistor amp) and the cab make its sound like a tube amp. It even has very clean and bright clean tones.
    As for bass guitar it sounds amazing to. But when you go up in volume the speakers have over-excursion. I tested it with an Ampeg SVT classic and with an Ashdown EVO II 500. With both amps the same problem.
    I already added a 4" bass port but by now I'm not sure if this would have helped (in case it needs to be sealed I can do this)

    How can I get rid of this extremely annoying over excursion?
    The cab sounds amazing in all it's ways. These words have been confirmed by a professional sound engineer who own a studio that runs well.

    The cab:
    - 2x10 + 1x15 in one cab.
    - speaker on top Ampeg 86-510-04. There is not much known about this speaker atm.
    it is the same speaker as in the Ampeg SVT 410HLF cabinets. It is 4ohm, 100watt and a 2" voice coil.
    - second speaker an Eminence Legend BP102 4ohm, 200watt, 40-2000Hz
    - speaker at the bottom an Eminence Delta 15 8ohm, 400watt, 48-4000Hz
    - speaker wiring is connected with a Plug and Play jack plate such as Jack Plate - Plug and Play, Mono/Stereo for more info about it scroll down.
    - But most of the time I use the 4ohm output. Which means the two 10" speakers are wired in series resulting at 8ohm. And this circuit is wired in parallel with the 15" 8ohm speaker. Which gives us 4ohm.

    - Made of 15 millimeter thick birch plywood
    - Made with box joints
    - outside dimensions height: 1020mm / width: 660mm / depth: 415mm
    - inside dimensions: height: 975mm / width: 630mm / depth: 355mm
    At this moment there is a wooden block glued on the bottom back as counterweight so the cab would be perfectly balanced. This block's dimension is (I'll write it in the same directions as the cab's dimensions) height: 170mm / width: 500mm / depth: 65mm
    - the cab is completely glued together and air tight. (I am a very precise working carpenter. So assume there are no leaks in the construction)
    - the cabinet is on wheels
    - has 2 handles holes (with handles in of course)

    Please help! I know I still have to learn a lot about bass enclosures. But I think I'm not doing a bad job.

    photo's info: I detached the bass port for testing. It is 4" and about 145mm long and normally the speakers are mounted with all screws instead of just 2.

    A BIG thank you to the man or woman who can help me out!

    Schermafbeelding 2018-01-20 om 19.47.55. IMAG0915. IMAG0916.
    IMAG0917. IMAG0919.
    Last edited: Jan 20, 2018
    alaskaleftybass likes this.
  2. First off, you have 3 different speakers ALL sharing the same airspace inside the cab.

    How can you build a cab around speakers without knowing the T/S parameters ?

    Bass cabs are a completely different animal then guitar cabs. You cannot just stuff speakers in a box and expect great results (as you are now finding out).
  3. Stevorebob

    Stevorebob Well... I Am Here, Aren't I? Supporting Member

    Sep 29, 2011
    Los Angeles
    Welcome to TalkBass!

    Ditto the mixed drivers and design points for an optimal speaker cab. The aside, you might want to fully secure those drivers. Bass freqs create some movement — might be that the drivers are simply rattling on the baffle.
  4. BassmanPaul

    BassmanPaul Gold Supporting Member

    Aug 25, 2007
    Toronto Ontario Canada
    Sorry @TijlT but you have built a cabinet that is all wrong for use with a bass.
  5. Raf Seibert

    Raf Seibert

    Dec 16, 2013
    Yes, with only two fasteners per driver that may we’ll be the source of your noise.

  6. Rick James

    Rick James

    Feb 24, 2007
    New Jersey
    Three drivers with different specs all in the same air space, a port that's way too small to not chuff, no damping material in the cab, no cross bracing in the cab, and a cab size and port dimension that who knows how you arrived at. You're lucky it works at all. The workmanship looks pretty good, but you didn't do the necessary research to learn how to design a speaker. Chalk this one up to lesson learned. You might be able to salvage it, but you need to learn the basics of how speakers work first. This is a very good resource: The Speaker Building Bible - Techtalk Speaker Building, Audio, Video Discussion Forum
  7. TijlT


    Jan 20, 2018
    As I said in my first post. On the photo they are only mounted with 2 screws. Normally with all 8 screws. So that is not the problem!
  8. I believe that different sized drivers in the same air space can be problematic.
    Aside from all of the other comments, you most likely need to divide the cab so the 15 is not interacting with tHe tens. But as others gave said, without modeling the cab to work with the speakers, AND that bass cabs are a more critical build than guitar or stereo cabs, it's all just a roll of the dice.

    Also, are you running it with those rectangular, open holes on the side, that appear to be for handles? I don't think that's going to help the cause either.

    BTW, Welcome to Talkbass. I hope you don't feel like you've bitten off more than you can chew.
    Take to heart, what all the others have said, they only want to help. Get back to the drawing board and see what you can do as a follow up. Don't be afraid to ask for help here. There are some really smart people here who know a lot about building bass cabs.
    Last edited: Jan 20, 2018
  9. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    This is probably time to take a "rest stop" and learn a bit more about speakers and their enclosures, and how/why speaker systems work. It will make whatever your next step is more productive.
  10. Stevorebob

    Stevorebob Well... I Am Here, Aren't I? Supporting Member

    Sep 29, 2011
    Los Angeles
    Sorry. Missed that.
  11. theduke1

    theduke1 Supporting Member

    Dec 22, 2010
    Manitowoc WI
    Peavey made a 1510 cabinet back in the 80s
    I played through one a few times sounded good at the time
    Point is if you look around you should be able to find a drawing of it somewhere
    alaskaleftybass likes this.
  12. BadExample


    Jan 21, 2016
    Welcome here bro!

    Egads! I'm going to go sit on my bed a cry now.
  13. theduke1

    theduke1 Supporting Member

    Dec 22, 2010
    Manitowoc WI
    My mistake Peavey made and still makes a 1516 bass cabinet
    A 15 with 2x8s
    eriky4003 and alaskaleftybass like this.
  14. smogg


    Mar 27, 2007
    NPR, Florida
    I'm not crazy, I'm just a little unwell
    Peavey did make the 1820 (18+210) & 3620 (2x18 + 210) back in the day. The tens were in a separate compartment IIRC. I did a show with a 3620 back lined and admit it was thunderous.
    SunnBass and alaskaleftybass like this.
  15. Yep - all the 2X10 sections were loaded with matching drivers (not mismatched as in the OP) and were separate and sealed. The 15's or 18's were ported.
    BadExample and smogg like this.
  16. lz4005


    Oct 22, 2013
    They sure did. As well as a cab with 1x10s and 1x18. In both cases the different size speakers were in separate internal chambers and there was an integral crossover. [edit: oops, two other people said the same thing while I was typing]

    Going full range into three different speakers in the same chamber is bad design.
  17. BadExample


    Jan 21, 2016
    3 Random speakers in a box ain't gunna cut it. I'm done crying now and onto binge drinking. Scrap this idea. Take the @agedhorse advice.
    kesslari, mohrds, bassmeknik and 2 others like this.
  18. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    Drinking sounds refreshingly inspiring right now ;)
  19. BadExample


    Jan 21, 2016
    I've diverted from my usual X-stout to cans with the nitrogen widget. If I can find an IN->CA wormhole, I'll send one your way.
    agedhorse and alaskaleftybass like this.
  20. Well, as others have said, it's not the best design going - you've got a good couple things wrong. It's okay though, it happens. If I may say, though - you put some good work into building the cabinet, and it shows.

    If I recall, the Ampeg svt410hlf drivers are remarkable similar to the eminence bp102. It's been a long time since I think I've heard that though. However, the eminence likes sealed chambers, in all honesty. At least from what I've been able to figure out. And if the Ampeg is anything like the eminence, it'll probably also want a sealed chamber. So maybe plug the port, and install a panel between the 15 and the 10s. Getting another eminence driver and dropping that in place of the Ampeg would also be a step in the right direction. From there, you could possibly run the Delta on a high pass at maybe 100-200 Hz. It has a very high sensitivity and power handling, but not so much excursion, so it'd be a great mid driver compared to the legends - but wouldn't handle as much low end. Or at least, it wouldn't handle the low end as well as you'd think compared to the two 10s.

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