30 inch speaker?

Discussion in 'Amps and Cabs [BG]' started by jim nolte, Aug 1, 2019.


  1. Vintage-Blue

    Vintage-Blue Gold Supporting Member Commercial User

    Feb 13, 2008
    Cincinnati, OH
    Owner, Vintage Blue (repro cabinets)
    Ampeg (or one of it's employees) built a 30" cabinet as what was surely just a one-off. It was loaded with an EV 30W. The first photo show it next to a B18N. The cabinet appears to have slotted ports much like the double baffle B15N & B18N.

    2ly0buv.jpg keb403.jpg
     
  2. Rick James

    Rick James Inactive

    Feb 24, 2007
    New Jersey
    Modern drivers made servo drive obsolete. Even Thomas Danley doesn't do that anymore, and he invented it. That B&C is a joke, for $1250 you can get a bunch of eighteens that would blow it away. Eminence has a soon to debut 21 that's a lot better, but at a grand it's not all that cost effective either.
    dB v2
     
    2tonic likes this.
  3. I think currently obsolete drivers made the 30" driver obsolete way back when, but here we are poking the turd.;) All that's old isn't necessarily gold.

    I use some horn loaded Lab 15s in my subs, and they move a lot of air with a minimal amount of power, but they certainly wouldn't be suitable for a full range bass guitar cab.
     
    Last edited: Aug 1, 2019
  4. Wasnex

    Wasnex

    Dec 25, 2011
    This data sheets specifies sensitivity of 99db at 2.83V and 8 ohms; so 1W. Xmax is a paltry 15mm.

    https://www.parts-express.com/pedocs/specs/294-6030--bc-21ds115-spec-sheet.pdf
     
  5. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa Boogie, Development Engineer-Genzler (pedals), Product Support-Genz Benz
    2 different drivers. Look at the sensitivity graph, averaging over their specified bandwidth of 37Hz to 1kHz is just about 90dB/1W/1M average broadband sensitivity on the 1 ohm driver.

    Now the one that you linked has a specified bandwidth of 30Hz to 1kHz and if you work out the average sensitivity it's also right about 91-92dB/1W/1M

    They could increase the calculated average sensitivity by specifying the frequency range to be say 100Hz - 1000Hz, but that's NOT what the intended application of the driver represents. So, either they are using a very limited and select frequency range for the sensitivity spec or they didn't correct for the impedance, but either way the sensitivity graph matches what I would expect.

    One giveaway that hints to this sensitivity is the Mms, the cone assy. plus air mass is about 1 pound!!! Same goes for the Eminence version so it's not a manufacturer specific thing, it's the natural consequences of this kind of moving mass and the limitations of the motor.
     
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  6. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa Boogie, Development Engineer-Genzler (pedals), Product Support-Genz Benz
    Do you know what the specified bandwith is for the sensitivity spec? That's another 1 pounder Mms.

    The challenge is that in order to get the desired performance, a lot of wire sits outside the gap at any one time which also hurts sensitivity. Pick your poison.
     
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  7. seamonkey

    seamonkey

    Aug 6, 2004
    After all these decades of minuturization it turns out a modern mini 18" can easily out perform a 30" of the past.
    ;)
     
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  8. keyboardguy

    keyboardguy Supporting Member

    May 11, 2005
    ...I just GOT to hear this thing !........:jawdrop: Isn't that the workplace of "Aged Horse"? :smug:

     
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  9. [​IMG][​IMG][​IMG][​IMG][​IMG][​IMG][​IMG]
     
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  10. Is that your shop? :)
     
  11. 2tonic

    2tonic

    Dec 22, 2015
    Yes. Rickenbacker brought him an amp with two 1x30" cabs to try during tour rehearsals, in '71 or '72, IIRC.
    He toasted 'em within 15 minutes, but commented that they sounded pretty "round" right up to the point where they seemed to emit smoke!
    Probably said "meh" and plugged back into his Acoustics. :thumbsup:
     
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  12. Wasnex

    Wasnex

    Dec 25, 2011
    Yeah, I don't know where they get the 99dB from. If you look at this page:B&C Speakers it shows a frequency response chart in a 130 liter box tuned to 40 hz and the sensitivity looks to be around 97dB up at 400hz. (click the third dot under the charts)
     
  13. 2tonic

    2tonic

    Dec 22, 2015
    I seem to recall Pink Floyd utilized 8 or 12 of these 60" subs in their mains, but solely for a special effect, not through the whole show. I'll have to search my reference materials to recall the specifics.
     
    Last edited: Aug 2, 2019
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  14. 2tonic

    2tonic

    Dec 22, 2015
    L'audace, l'audace........toujours l'audace!! :D
     
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  15. Robscott

    Robscott

    Mar 20, 2017
    Tonbridge UK
    I thought you guys had a few of those pointing at Moscow?
     
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  16. BtaylorTheRogue

    BtaylorTheRogue

    Nov 14, 2016
    You heard it here, folks, AgedHorse officially says smaller is better: all 10 inch speakers are better than any 15 inch speakers.

    /popcorn
     
  17. SteveIII

    SteveIII

    Jul 11, 2019
    Oshawa Ontario
    They show a different graph if you download the spec sheet. Still only looks like it hits 98or so in two spots. Perhaps marketing writes the blurbs and stuff from the charts the r and d dept. Provides?
    Curiously enough I checked the math about the 99db driver producing 128 db at 800 watts, why then would winisd model my 99db/1m 15s from b and c hitting 128 db at 400 watts from my 2x15. As in 200 watts per driver? Are b and c s efficiency numbers just all over the map maybe? Maybe they just like the number 99?
     
    Wasnex likes this.
  18. But it seemed like a good idea at the time. :laugh:
     
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  19. wmhill

    wmhill Inactive Suspended

    Aug 20, 2012
    upstate NY
    MTD basses endorsed artist Bartolini pickups emerging artist TECAMP bass players gear endorsed
    I did some gigs with a guy that had a pair of 30" EVs, mounted in the ceiling of his rehearsal space/living room. I made it a point to avoid standing below them.
     
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  20. Rick James

    Rick James Inactive

    Feb 24, 2007
    New Jersey
    The Eminence magnet is 45 ounces of neo, compared to 11 ounces in the Kappalites, so that overcomes the high Mms. In 7 cu ft net tuned at 30 Hz it has 95dB/w (2.44 volt) sensitivity with a 30 Hz F3. Maximum calculated displacement limited SPL is 130dB, but you can get that with a pair of eighteens that cost a lot less. Bigger isn't always better, but so long as some people continue to think so there will be products out there for them.
     
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  21. 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.

     
    Jul 26, 2021

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