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How Do You Get 4-Ohms out of a SVT 6x10"?

Discussion in 'Amps and Cabs [BG]' started by Bongolation, Aug 23, 2005.

  1. Bongolation


    Nov 9, 2001
    No Bogus Endorsements
    A guy's trying to sell me one of these and according to the Ampeg site, it is indeed a 4-Ohm cab...

    But I've been sitting here trying to figure out how you can get four Ohms out of SIX typical 8-Ohm or 16-Ohm drivers.

    Anybody know what's in these things? Are they non-standard impedance drivers (which I would want to avoid), or what? Am I just missing some non-obvious arithmetical solution in my head? :confused:
  2. jiant.


    Jul 3, 2004
    Fort Mill, SC
    I have no clue, this is a complete guess, but maybe 4 of the drivers are 32 ohm and the other two are 16 ohm, or somthing like that.
  3. Kael


    Dec 26, 2004
    Oklahoma City
    If parallel then...

    1/Rt = 1/R1 + 1/R2 + 1/R3 +...
    Rt = R (t)otal


    1/4 = 6*(1/x) = 6/x
    x = 24

    so I guess they could be 24 ohm drivers?
  4. Matt H

    Matt H

    Jul 30, 2005
    Ithaca, NY
    well, speaker impedance varies by frequency ANYWAY...

    so the difference between a "nominal 2.6 ohm" and a "nominal 4 ohm" cab would actually be very minimal under most circumstances.

    (keep in mind the average DC resistance of a "4 ohm" speaker is generally around 3ohms anyway)

    however- 24 ohm drivers DO seem like they might be the ticket if the cab is ACTUALLY 4 ohms.

    also, they could wire up 4 4ohm speakers in series/parallel for 4 ohms (call it unit 1), then run a pair of 8ohm speakers (which are themselves in parallel) (call it unit 2). Then run unit 1 and unit 2 in series.
  5. Or they could be 6 ohm drivers. 2 in series= 12 ohms

    Three sets of those pairs in parallel would be 12/3=4 ohms.

  6. Masher88

    Masher88 Believe in absurdities and you commit atrocities

    May 7, 2005
    Cleveland, OH
    More than likely Ampeg gets custom drivers with special impedances made for them. Alot of companies get drivers made specifically for only them to use.
  7. Petebass


    Dec 22, 2002
    QLD Australia
    OR, they're 6 x 8 ohm speakers which comes to 5.3 Ohms, and Ampeg marketing department has decided it's close enough to 4 ohms.

    The easiest way to solve this is to ask the guys who's selling it to you to pull out one of the speakers and read what's on the back.
  8. Fuzzbass

    Fuzzbass P5 with overdrive Gold Supporting Member

    The Bergantino NV610 uses 24 ohm speakers. The Ampeg 8x10 cabs use 32 ohm speakers, but I don't know what's in their 6x10. Nor do I know what speakers are used in the 4-ohm SWR Goliath Sr. 6x10.
  9. Matt H may have nailed it. I'd heard that the center 2 speakers have a tendancy to distort in advance of the up and lower pairs.
  10. 12bass


    Jan 2, 2003
    Victoria, Canada
    The Eden D610XLT uses six 8 ohm drivers and is 5.3 ohms. There is a good chance that Ampeg simply called the cabinet 4 ohms, even though it is probably 5.3.
  11. Jerrold Tiers

    Jerrold Tiers

    Nov 14, 2003
    St Louis

    Nope, both wrong .....

    The cabinet uses 6 ohm speakers, as steveksux suggested.
  12. Hey, just a lucky guess. Just trying to figure ways to do it where all speakers get equal power (unlike the asymetrical hookups some mentioned, with some of these hooked up like this, and some of those hooked up like that...).


    And they said high school algebra would never come in handy! :D
  13. Petebass


    Dec 22, 2002
    QLD Australia
    Out of curiosity, why do you want to avoid non-standard impedance drivers?
  14. Matt H

    Matt H

    Jul 30, 2005
    Ithaca, NY
    probably because in the event one (or two) blow/s, it's a lot harder to get a replacement, and MUST go through the company you bought the cab from...

    possibly even years down the road, when the warranty is no longer valid.

    additionally, you can't swap out speakers for different tones and mix and match. this seems to be less of an issue in the bass world, but it's very common for lead guitar to mix and match speakers within the same cabinet.
  15. Petebass


    Dec 22, 2002
    QLD Australia
    With Thiele-Small parameters being what they are, swapping out speakers not a viable option most of the time anyway. You can swap one 8 ohm speaker for another, but that's only one out of a dozen T/S parameters accounted for.

    Not all 10's ar equal. Put the wrong speaker in the wrong sized cab and/or with the wrong port tuning, and even a brilliant speaker will sound and perform like garbage. Even with standard 8 ohm speakers, getting original replacements (or recones) is often the best way to go.
  16. Bongolation


    Nov 9, 2001
    No Bogus Endorsements
    Ah, thank you Jerrold! My man! :p

    OK, so I'm not crazy and my arithmetic still works!

    OK, here's one for a bonus point, while I have your attention:

    Do you know what the power handling capacity was of the circa-1975 SVT 2x15" cabs? A guy's trying to sell me one of these, but I'm afraid these old '70s drivers are too low-rated. The current SVT-215E only claims 400WRMS handling.

  17. Probably in the event one or two blow, you need to replace them with stock speakers.

    The "quality" of the replacement speakers doesn't matter much at all compared to how well it matches the cabinet, i.e. the small Thiele parameters effect on the sound.

    You could put a "way better" replacement speaker in that would sound like absolute crap because it doesn't match the cab tuning.

  18. timv

    timv Supporting Member

    Jun 7, 2000
    Chandler, AZ
    The swr 6x10 cabinet uses 8 ohm speakers so it isn't an actual 4 ohm cabinet. I know, I had to replace one that was blown when I got it.
  19. jasonbraatz


    Oct 18, 2000
    Oakland, CA
    Good thing I stumbled across this thread, I was just about to post to ask this!

    Thanks man :)
  20. Jerrold Tiers

    Jerrold Tiers

    Nov 14, 2003
    St Louis
    No I do not, at least not off-hand. it might take some serious digging..........

    But I would be willing to bet that it isn't as high as current 15" speakers.....

    With no other info to go on, I'd suspect around 50 to 100W per speaker.....

    What size are the voice coils? I don't have a comparison unit.