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New speakers for Ampeg V-4 cabinet

Discussion in 'Amps and Cabs [BG]' started by davelowell2, Dec 15, 2006.


  1. davelowell2

    davelowell2 Uhh... FaFaFooey is BaBaBooey... Supporting Member

    Apr 20, 2006
    NYC via StL
    Let's have a little hypothetical moment here...


    My guitarist leaves his cab here at my house, and long story short, I played my SVT through it AT LOW VOLUME. I really like the sound and it matches my amp's cosmetics.

    So assuming I can find one of these cheap (I can), what would be some nice bass speakers to put in there to make a 4 ohm load? The cab is sealed. What info would you like to help figure it out? The measurements of the cab are 30 in wide, 27 in tall, and 14 in deep. The front baffle is inset about 2 inches, so let's say that the depth is 12 in, on the inside.

    Thanks for all of your help in advance.

    Dave
     
  2. BillyB_from_LZ

    BillyB_from_LZ Supporting Member

    Sep 7, 2000
    Chicago
    Well..let's see. If you know the volume (which you can calculate) and you know the Thiele-Small parameters of potential drivers you can plug the data into WinISD and see what happens.

    As for potential drivers...look at Eminence Delta 12LFs (the LFs are designed for smaller cabinets...don't know about sealed ones though, but it's worth a try). Other suggestions might be WeberVST Michigans which are modeled after EV SROs, another WeberVST if they are similar to Altecs since I read here on TB that Ampeg offered a bass version of this cabinet loaded with Altecs and maybe even EVM 12Ls (didn't/doesn't Steve Harris use EVM loaded Marshall 4x12s for bass?).

    Having typed all that I re-read you 4 ohm requirement which would mean that you need either 4 ohm or 16 ohm speakers. The WeberVST Michigan12s come in 4, 8 and 16 ohm impedances. https://taweber.powweb.com/weber/ in the high power series.

    It looks like Avatar uses 4 ohm Neos in the SB112. Not sure how that speaker would perform in a sealed box.
     
  3. Ben Clarke

    Ben Clarke Liquidating to fund a new business. Buy My Gear!

    Jan 6, 2005
    Western NY
    How about Altec 414? Pretty much any 4 decent 12"ers in a sealed box should take 300W - it's only 75W per driver. JBL D-120 would probably be nice and punchy.

    I had the old big Ampeg 4x12 when I was a kid. The one that's about 4 feet high. The seller said it had Altecs in it originally but he loaded it with Peaveys. Heavy pig... Coulda sounded OK, but I really didn't know what I was doing at the time...
     
  4. davelowell2

    davelowell2 Uhh... FaFaFooey is BaBaBooey... Supporting Member

    Apr 20, 2006
    NYC via StL
    Thanks for the suggestions, fellas!

    The problem I have is, I can put all of these numbers into WinIsd, but I don't have a clue about what they all mean. That's why I am looking for some guidance about what could work.

    Thanks, anyone know a lot about speakers and stuff that wouldn't mind donating some of their expertise?

    Dave
     
  5. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
  6. davelowell2

    davelowell2 Uhh... FaFaFooey is BaBaBooey... Supporting Member

    Apr 20, 2006
    NYC via StL
    Anyone else wanna help a brother out?

    Dave
     
  7. BillyB_from_LZ

    BillyB_from_LZ Supporting Member

    Sep 7, 2000
    Chicago
    Back in 2003 when I was reading The Bottom Line, a similar scenario came up... Here's what happened.

    "A couple weeks ago I came to TBL dreaming out loud about assembling a cab to match my old Ampeg V-4B head, which I "unretired" for a weekly blues jam we're now hosting; a "Mini-SVT" using 2-12's. Something smaller than the old V-4 bass cabs, which were a true roadie's nightmare in their day. I got
    some good suggestions from you, and thanks in particular to help from fellow TBL'er Bill B, it was much easier to realize than I expected.

    Bill suggested that there might be some "unloved" V-4 guitar cabs living in obscurity, having passed out of fashion, and he even sent a link to a picture of just the thing I had in mind. It's sized similar to the smaller 2X15 cabs some of us grew up with. He suggested that w/some rebaffling it might work well for bass. This one in particular had been on E-Bay at $199 to start and got nary a bid. When I contacted the seller he was eager to
    move it out at a very reasonable priceand happy to keep the '76 CTS 30 watt guitar speakers it was loaded with, considering them the better end of the deal. W/out the speakers it was not as much of a beast to ship and was on my porch within a week. It turns out that '76 is also the vintage of my amp, so not only do they look like litter mates, but they even look a bit like they've been through hard-knock school together. And like other '70's Ampeg gear, it's built like a tank w/heavy birch plywood.

    Bill also recommended Eminence Delta LF's as drivers, and steered me to Avatar Cabinets. The 12" Deltas are very rugged and their response fairly flat from about 45 Hz to about 3k, w/a nice little peak at 3k, which works for me. Avatar's price was great and their responsiveness excellent.

    As Bill had suggested, I worked w/a number of the free speaker cabinet design tools on the web to decide whether and how to port the cabinet. It was a bit of a crash course for me, but w/lucky results. It turns out that theinternal volume of V-4 enclosure is large enough accommodate the Delta LF driver specs in a sealed cabinet w/a -3db frequency of right around 58 Hz.

    Given the gradual low end roll-off of a sealed enclosure below that, it seemed worth a try for starters, rather than various porting schemes, all of which seemed to involve one trade-off or another. in order to achieve low end from smaller boxes.So I installed the drivers in the 10 o'clock and 4 o'clock holes, and covered the 2 o'clock and 8 o'clock holes w/some 1/4" lexan countersunk and screwed in place; no baffle mods at all.

    I was a little worried about adequate volume and low end w/the
    sealed box, but was pleasantly surprised with the results. The box is even and punchy right down to low-B, very clean in fact, and tremendously powerful. A/B'd with my Eden 210 XLT, the house shook noticeably more at the same amp volume. It's a beast! Which of course is it's downside, too.

    W/68 lbs. of cabinet and 26 lbs. of speakers, it's definitely not a
    "compact" (nor is the V-4 head, for that matter). Put in perspective, though, it's about the size and weight of a heavy-duty 4X10, and I think it probably covers most of thesame sonic territory. Without a crossover and tweeter it's probably better for blues than for tap-n-clankin', though
    there's plenty of room left over for such devices if one wanted to get creative w/design. All in all, a very fun and effective "vintage" cabinet for right around $300 plus just a little sweat equity.
    "

    So it sounds like using two 8 ohm Delta 12LFs and making filler plates for the other two holes is a workable solution.
     
  8. davelowell2

    davelowell2 Uhh... FaFaFooey is BaBaBooey... Supporting Member

    Apr 20, 2006
    NYC via StL
    Billy, thank you for that. I have not read anything like that, so now I have more to think about. :)

    I guess finding 4 proper speaks, short of guitar speaks, is out of the question for the size of this box... Well, it was worth try anyway.

    Dave
     
  9. BillyB_from_LZ

    BillyB_from_LZ Supporting Member

    Sep 7, 2000
    Chicago
    Out of the question...no not really. It's a relatively small box so you need speakers that will perform well in a small box. An equally important issue is that you want the box to have a 4 ohm impedance. In a 4x configuration, that means that you'll need speakers that are either 16 ohms (all connected in parallel) or 4 ohms (series-parallel). That automatically rules out 8 ohm speakers , which are the most common.

    If you can live with a 2 ohm cabinet, then 8 ohm speakers are back in... A cabinet for a modern SVT with 4ohm /2 ohm selector switch could be wired 2 ohms mono. For an older SVT with two speaker jacks looking for 4 ohms each (plugging into the Ext. speaker jack automatically switches taps on the output transformer), you could wire a 4x cabinet in stereo (two paralleled 8 ohm speakers per jack) and the amp would be happy.

    More to consider!

    I know (or I'm pretty sure) that Lemmy, Steve Harris and Dusty Hill have all had guitar sized 4x12s as their bass cabinets. Perhaps a little research in that direction would turn up some choices. I believe both Steve Harris' and Dusty Hill's cabinets were loaded with Electro-Voice EVM 12Ls. While technically guitar speakers, they really sound good for bass (really good to my ear) if you're not looking for bowel loosening low end.

    Having typed all that, I seem to recall that there's a particular Eminence 12 that is modeled after the EVM 12L. I'll have to see if I can track that down. Mike Holland, of guitar amp fame, used to sell a private labeled version of them on his site, I believe he sold his amplifier business to another company.

    Bill Fitzmaurice...if you know which speaker I'm referring to, please let us know.
     
  10. BillyB_from_LZ

    BillyB_from_LZ Supporting Member

    Sep 7, 2000
    Chicago
    Looking at www.Eminence.com and then at www.harmony-central.com in the user reviews for guitar amps...several reviewers mentioned the EVM 12L - Eminence Delta Pro 12 connection.

    So...you might want to consider Eminence Delta Pro 12 (available only in 8 ohm impedance).
     
  11. BillyB_from_LZ

    BillyB_from_LZ Supporting Member

    Sep 7, 2000
    Chicago
  12. davelowell2

    davelowell2 Uhh... FaFaFooey is BaBaBooey... Supporting Member

    Apr 20, 2006
    NYC via StL
    Yeah, I have an older SVT without the impedence selector. I never thought about wiring the cab in stereo to get two 4 ohm sides. That is just awesome, I'm back in business baby!!

    Thanks BillyB
     
  13. davelowell2

    davelowell2 Uhh... FaFaFooey is BaBaBooey... Supporting Member

    Apr 20, 2006
    NYC via StL
    Ok, how about this one? Better suited for what I want, or is the Pro12A?



    DELTA 12LF







    Nominal Basket Diameter
    Impedance
    Power Rating
    Resonance
    Usable Frequency Range
    Sensitivity
    Magnet Weight
    Gap Height
    Voice Coil Diameter

    Mounting Information
    Recommended Enclosure Volume
    (vented)
    Overall Diameter
    Baffle Hole Diameter
    Front Sealing Gasket
    Rear Sealing Gasket
    Mounting Holes Diameter
    Mounting Holes B.C.D.
    Depth
    Shipping Weight

    Thiele-Small Parameters
    Resonant Frequency (fs)
    Impedance (Re)
    Coil Inductance (Le)
    Electromagnetic Q (Qes)
    Mechanical Q (Qms)
    Total Q (Qts)
    Compliance Equivalent Volume (Vas)

    Peak Diaphragm Displacement Volume (Vd)
    Mechanical Compliance of Suspension (Cms)
    BL Product (BL)
    Diaphragm Mass inc. Airload (Mms)
    Equiv. Resistance of Mechanical
    Suspension Loss (Rms)
    Efficiency Bandwidth Product (EBP)
    Voice Coil Overhang (Xmax)
    Surface Area of Cone (Sd)
    Impedance at Resonance (Zmax)
    Maximum Mechanical Limit (Xmech)




    12", 304.8mm
    8 ohm
    500Wrms / 1,000w Peak
    45Hz
    45Hz - 3kHz
    97 dB
    56oz.
    0.375", 9.52mm
    2.5", 63.5mm


    85 - 142 liters
    3 - 5 cu. ft.
    12.02", 305.2mm
    11.05", 280.7mm
    fitted as standard
    fitted as standard
    0.25", 6.4mm
    11.63", 295.3mm
    5.35", 136mm
    13.6lbs., 6.2 kg.


    45Hz
    6.06 ohm
    1.45mH
    0.45
    7.28
    0.42
    67.88 liters
    2.4 cu. ft.
    241cc
    0.24mm/N
    14.1 T-M
    51 grams

    2.27N*sec/M
    101
    4.8mm
    506.7cm2
    93 ohm
    26.92mm
     
  14. BillyB_from_LZ

    BillyB_from_LZ Supporting Member

    Sep 7, 2000
    Chicago
    I think that either one would work (although I didn't run the numbers).

    It is my understanding that the Delta 12LF is a 12 that thinks it's a 15...great low end, less high end. The LF versions were specifically designed by Eminence to work in smaller enclosures.

    The Delta Pro 12 being similar to an EVM 12L will have punchy lows and probably more upper mids. One one H-C review said it's like an EVM 12L but not as bright.

    Since you're using a sealed box and don't have to worry about box tuning, you could always use two of each and enjoy the blended response of the different drivers...

    Have fun!!!
     
  15. davelowell2

    davelowell2 Uhh... FaFaFooey is BaBaBooey... Supporting Member

    Apr 20, 2006
    NYC via StL
    Now, is xmax supposed to be a high or low number for a sealed box? I can't remember which.
     
  16. davelowell2

    davelowell2 Uhh... FaFaFooey is BaBaBooey... Supporting Member

    Apr 20, 2006
    NYC via StL
    Any xmax info or ideas?
     
  17. greenboy

    greenboy

    Dec 18, 2000
    remote mountain cabin Montana
    greenboy designs: fEARful, bassic, dually, crazy88 etc
    Bill's suggestion should not be overlooked. Failing that, model drivers you are interested in using WinISD Pro (the old WinISD won't tell you a thing about excursion in a given box). A lot of people assume that a sealed box will prevent overexcustion but that's driver- (and signal-) dependent.

    In some cases, the Eminence neo speakers will do just as well or better than applicable non-neos.
     
  18. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    All else being equal it will allow less excursion at the same input power. Less excursion= less output. That's not necessarily a positive attribute.
     

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