10" replacement speaker (for a combo)

Discussion in 'Amps and Cabs [BG]' started by Giraffe, May 23, 2005.

  1. I have an old Roland Super Cube 40 Bass amp that I got in a trade. It is a solid state, one 10" combo with a semi-parametric and bass and treble shelving filters. It is about 12.5" square and pretty lightweight. This amp seems to have potential. I patched it to an Eden D-115 and the head seemes fairly clean and toneful, but the internal speaker sounds fairly shot and beyond nasal as well!

    I think it is worthwhile to replace the 8 ohm internal speaker. The enclosure is an infinite baffle (no vents) and the internal volume is only about 1,035 cubic inches (without accounting for the volume taken up by the speaker itself). That's a pretty tiny enclosure (12"x11.5"x7.5")!

    What do you think I should look at for a replacement? I believe the output is 40 watts RMS, so handling capacity is not much of an issue. I am looking for a wide, fat bottom and as little distortion as possible. Any suggestions?
  2. Petebass


    Dec 22, 2002
    QLD Australia
    Not to be nit-picky but "infinite baffle" means the speaker has no cab. If the speaker is in a cab with no ports, it's simply "Sealed".

    And herein lies your problem. Very few Pro audio drivers are designed to be used in sealed cabs. I won't bore you with the science of it all unless you ask me to. But IMO you'll have a better chance of finding a good replacement speaker if you're prepared to buy a port from Parts Express, cut a hole for it, and transform it into a vented enclosure.

    Here's your third problem. Fitting a port into a cab that size means you may not be able to tune it as low as you need to.

    For example, the Beyma 10LW30/N might be a good choice for a small cab, but it needs to be tuned to 38Hz. The only way that can happen in a cab that small is a 1" diameter port that's 3.39" deep. That's a small hole and you might get "whistling" and making chuffing noises. To make the hole any bigger means the port has to be deeper, too deep for your cab.

    If you're prepared to try it, other speakers to look at are the Eminence Kappa Pro 10, B&C 250AMX, RCF L10/568H, Beyma 10M250, B&C 10HPL64, Beyma 10G40, B&C10PS26, or Eminence Delta 10. This list is order of ascending prefered cab size, so the Kappa Pro 10 for example likes a smaller cab than the Delta 10.

    Please not none of these will produce bottom end in any magnitude.
  3. Nedmundo

    Nedmundo Supporting Member

    Jan 7, 2005
    Maybe try Carvin. They sell a decent 200 watt 10" driver they use in their PB100-10 combo, which I have and sounds excellent -- for a 100 watt 1x10" combo, that is.
  4. First, thanks for the suggestions! It is a little surprising how little help the speaker manufacturers are in providing recommendations for cabinets for their own speakers. This seems like an essential spec, but it is not readily provided on most of the websites. Additionaly, a lot of the different manufacturer's lines change often, so getting info on speakers that are currently available is tough.

    I'm planning on using this amp for ultra-quiet applications, "acoustic" music played with a fretless Rick Turner Renaissance. I'll try a five string, but I suspect that the power and size limitations of this amp will restrict me to using the four. Since The top end detail becomes very important in that setting, I considered a tweeter, but this enclosure is too small. Eminence has a 200 watt tenner in its Legend series that features a whizzer cone, and it costs less than $100, so I may try that one out. The enhanced top end might bring this unit to life a little. The nasal, midrange honk of so many smaller, cheaper amps drives me nuts. The Carvin is an appropriate replacement price-wise, but their cabs have always sounded lifeless to me, so I will try to find a more hi-fi alternative.

    I like the suggestion of adding the port. This cab is probably too cramped for the port to work properly, but I am going to check this option out for future reference.

    "Infinite baffle" is a term commonly used in the U.S. to describe any enclosure that prevents the back radiation of a speaker from meeting the front radiation in a detrimental manner. This could mean a flat board 50' by 50' if the speaker is mounted in the center, or a totally sealed box. Unless I can figure out how to fit a working port in here, I'm afraid that's what I'm stuck with! I'll report on how the Eminence (I think it is a BP-102) works out.
  5. Petebass


    Dec 22, 2002
    QLD Australia
    That's a nice 10" speaker, but it's T/s parameters indicate a cabinet of around 60 litres (2.19cu.ft). That's a larger cab than what you've got.

    How handy are you with power tools and plywood? Is making a cab for it out of the question?

    BTW the reason manufacturers don't release too much data is they like to keep their trade secrets.....well.... secret.
  6. I don't think this little 40 watt head warrants building a new cabinet, especially when I see visions of an Acoustic Image head in my future. Additionally, the size of this combo is one of its best features!

    I took a look at the Parts Express web site. I think maybe a vent, maybe in the rear, might make some more options available, but the most current info I have on cab design and port size and depth is from the seventies. How would I go about getting up to speed on this subject? I've got some other cab projects in mind, but I'm unprepared upstairs!
  7. Petebass


    Dec 22, 2002
    QLD Australia
    Short cuts are for people who know what they're shortcutting. There's no "quick" way to leard about cab design. I've been going at it for years and I'm still learning.

    The quickest way is to Download Winisd! It's basically a push-button cab design program and it's free.

    Ask lots of questions here, but try to keep them specific. There's lots of guys here who know their cab design theory, but they won't design a cab for you from scratch. There's too many variables for that.

    Read Vance Dickason's "Loudspeaker design Coockbook". It's the bible of cab design, but it's a heavy read so you mioght want to use one of the many ispeaker building websites as a supplement.
  8. Thanks for the advice. I'll find some sites and get started. I just stumbled across some 18" wide, 3/4" clear pine lumber, and I have been thinking of building some guitar cabs with it. Then maybe putting a nitro lacquer tobaccoburst finish on them. You know, for your living room!
  9. Rick Turner

    Rick Turner

    Jul 14, 2004
    If I've learned anything about loudspeaker design in 40 years it's that a wide, clean midrange is more important than anything else. I'd rather sacrifice a bit of deep low end than have a muddy mid. My faves are three way cabinets with very wide mid-range drivers covering between about 500 Hz and 3.5 K Hz. That's the inttelligibility zone, and it shouldn't be sullied by a crossover. Just my opinion, your mileage may vary...
  10. That makes sense to me. A muddy midrange is hard to ignore (especially in acoustic music), no matter how beautiful the bottom is. That sound reminds me of the underpowered, low quality amps and speakers of my youth. Take a good amp, plug in a short scale Gibson EB-3, bury the speaker under a pile of mattresses, and turn it up loud! Gives me chills.

    So maybe I'll think about building a three way cabinet with a twelve, a crossover at around 200 to 250 Hz, a high end ten to handle the all important mids, and a tweeter on top. Sounds like a light version of a Bergantino HT322. I know players who swear up and down that the 322 is the definitive answer to all the world's problems, so maybe this is worth noodling with. I could finish the cabinet in nitro lacquer over a faint amber blond, make a retro "tv" style baffle for it, put an Acoustic Image head on top, and plug in my Renaissance. Clear, lightweight, and loud. I just hope the piano player doesn't get too frightened when that bass starts to growling like three angry, inbred dogs!
  11. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    In some circles I've seen this definition used also, but Tom is correct that the classic definition of infinite baffle is one where the front wave and rear wave never meet. That can be done by installing the driver in the ceiling or floor, letting the attic or basement be the enclosure, or in a wall, letting the room abaft be the enclosure, or a simple sealed box. It works the same way in each instance, it's just a matter of scale, and having the correct T/S specs for the particular install.

    I'd recommend against the combination of a twelve and a ten. The difference in their relative responses is too slight. A twelve with a good bottom, like the Delta 12 LF, along with a closed-back eight or six like the Alpha 8 MR will give a far better midrange than any ten, especially when it comes to dispersion, which is limited by cone size. Crossover at 500 to 800 Hz, there's no reason not to take a 12 that high. Depending on your taste a tweeter may not be necessary, as an Alpha 8MR will run to 3.5-4kHz quite nicely with good dispersion. Above that a piezo tweeter will do, they're very smooth above 4kHz, and a dynamic tweeter just complicates things with the need for a proper crossover, but if you do go dynamic use one with a 90x90 dispersion pattern, not the 90 x40 usually seen in PAs, so that you can hear your axe as well as you audience does.
  12. Bill, could you tell me who manufactures those speakers? Visiting your website has piqued my interest. Maybe I would like to try a Tuba 24!