4x8" speaker options

Discussion in 'Shock Brother's DIY Amps' started by NSB_Chris, May 9, 2021.

  1. NSB_Chris

    NSB_Chris Tele-Meister

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    For some time now I have contemplated experimenting with some different speaker cab options. This thread has pushed me forward: https://www.tdpri.com/threads/four-5”-micro-bassman-build.1070972/

    I have decided to make a 4x8" speaker cab. First order of business is to purchase the speakers. I don't see many options in the 8" size. I think I want 8 ohm so that the assembled impedance is 8 ohm.

    Options that I see:
    1. Weber "Ceramic Signature 8" (15W)
    2. Jensen C8R (8 ohm, 25W)
    3. Celestion "Eight 15" (15W)

    I think the price is pretty similar for all 3, but I am leaning toward the Weber. They state that the Signature 8 is intended to have earlier breakup than the 8S.
    Any thoughts, advice, experience to share?

    Cabinet will probably be made from 1x12 pine walls with maybe a 1/2" plywood baffle. So probably about 9" or 10" deep from the back of the baffle. Was thinking of making it so that it could be both closed back or semi open back. Inside dimensions will likely by 20"x20" so the size will not be much larger than my existing 1x12 cabs. You can go mad trying to make sense of all the information on what internal volume is appropriate for closed back. For closed back it would have 3600 to 4000 cubic inches internal volume.

    I saw one recent post that had the info that the semi-open back area should be about the area of the speaker, so for four 8", that will be about 20" wide by 10" tall opening in the back. More to come on that.
     
  2. PhredE

    PhredE Tele-Afflicted

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    Just a suggestion: I think you'll get optimal feedback if we know something about what amp(s) it is to be paired up with.

    I'd also add the WGS G8C to the list just in the interest of completeness.
    https://wgsusa.com/8-g8c-20-watts#specs

    Also, I'd also recommend giving serious consideration to mixing say, one pair of speakers with a second pair of a different speaker type (can be tricky, but results can be uniquely interesting).

    The pine box with ply baffle sounds good to me. I think you're right on track with the basic design.
     
  3. Phrygian77

    Phrygian77 Friend of Leo's Gold Supporter

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    I also like the G8C. I put one in a '66 Champ that had an oddball non-original speaker in it. I was impressed.
     
  4. nojazzhere

    nojazzhere Doctor of Teleocity

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    GREAT IDEA!
    In general, I prefer Jensen (or Eminence copies) for my amps. The cab I built (seen in the thread you linked) is a combination of three Celestion (Vox) eights and one Jenson C8R......and they sound good together. My construction was very like what you propose, but I prefer open back cabs, like a Tweed Bassman.
    People (other guitarists) have been surprised at how good and "punchy" mine sounds, with the Vox Pathfinder 15R chassis. Good luck! ;)
     
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  5. VintageSG

    VintageSG Friend of Leo's Ad Free Member

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    I'm not familiar with the Weber. The Celestion Eight-15 is a good speaker. It finds its way into many low powered combo amps and 1x8" companion cabs for micro heads because it offers acceptable performance for not much money, plus, it's a 'name' speaker made in China, so no additional shipping.
    Whilst it's sound is OK in isolation, it's when you compare it to the Jensen MOD, their ceramics or their Alnico offerings that you realise there are better offerings on the market. It's a good speaker. It helps make a good noise, but it has as much character as cheap, sliced white bread. As a platform, it'll do. If you've ever played a small valve combo with one, you've thought it OK. Then you swap it for a Jensen MOD ( in my case, fanboi alert ), and the whole amp wakes up. 7x5" colour print compared to 7x5' Kodachrome projected in a darkened room onto a lenticular screen.
    While it's often not worth swapping them out, personally, I wouldn't build with the Celestion. However they, along with their 10" and 12" brethren that also get maligned, do sound rather good with solid state, highways of pedals and modellers .

    The Jensen MOD 8-20 has nicer lows and the real upper end has a sweetness the Celestion can't match. The Celestion may well be more accurate, but the Jensen sounds nicer. The Jensen P8R is warmer still, and its relative lack of clarity is most pleasing. The C8R ( to me ) works best when driven by a small valve amp on the verge of blowing up. Otherwise, meh. It is crystal clear, which may appeal.
     
  6. bottlenecker

    bottlenecker Friend of Leo's

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    I've been planning to do this for a while, and coincidently, a friend just contacted me about some speakers he wanted to get rid of just as I was reading the mini bassman thread.

    So I currently have nine 8" ceiling speakers with little transformers on them (for daisy chaining in original application). 4 of the speakers are JBL 8120. The others I forget the branding of, but I'll start with the JBLs first. They are 8 ohm.

    Here's a random pic from google.

    fJBL_8_Full_Range_Model_8120_Speaker_Perf_598ff6a750f49.jpg

    I will probably try to rebaffle an existing 1x12 cab, or convert an old ss combo, and power it with a champ.
     
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  7. NSB_Chris

    NSB_Chris Tele-Meister

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    Thanks!
    • I have several home grown heads that could be used depending on which ends up sounding best. JCM800 preamp with dual 6V6 power section.
    • Deluxe AB763 with dual 6V6
    • Single ended vibro champ
    Really nothing over 25W and even if I did put my 50W JMP2204 on it, I would never drive the speakers hard enough to get into trouble. Loudest I get is 90 to 100db in a reasonable size studio room standing 10 to 12 feet away. Not even close to getting a 12" speaker into compression territory I suspect. I am either playing through two amps and cabs in the studio or at bedroom levels with a clean little amp and pedals. The guy that owns the studio I play in has a 4x12 cab that sounds huge with a tone of low frequency growl at reasonable volumes. I am not going to lug a beast like that around and don't want to store it if I have to bring it home. At best a cab like the 4x8 will be an improvement over my 2x12 or at worst I expect it will provide some character being driven next to another 12" speaker cab.

    I also now see the Weber 8VF (60W) option. I will check out the speaker you referenced.
     
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  8. PhredE

    PhredE Tele-Afflicted

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    Don't want to derail the thread, but I also like smaller JBL type speakers too -- :)
    (I've posted about this one at least once before, but this little guy was made by the JBL subsidiary in Brazil. It's technically a midrange PA speaker. It's popular among guitarists/bassists -- not a loud one, but a very sweet response curve. No longer in production.. :cry:

    DSCN0941.JPG
     
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  9. PhredE

    PhredE Tele-Afflicted

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    OK, got it. Here's a quick list to summarize Power/Efficiency for the 4 speakers mentioned so far:
    (spacing might get hosed due to auto-formatting.. )

    -----------------SPL Power---------

    Celestion 8-15 95db, 20w
    Jensen C8R --- 93db, 25w
    WGS G8C ---- 95.6db, 20w
    Weber 8" ----- N/A, 15w
     
    Last edited: May 9, 2021
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  10. bottlenecker

    bottlenecker Friend of Leo's

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    That's a lot of power handling and a big magnet. What do you power it with?
     
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  11. PhredE

    PhredE Tele-Afflicted

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    https://www.tcelectronic.com/product.html?modelCode=P0DI5

    I'm more partial to jazz/clean tones of late. So, I've ditched the tubes (minus my BK Butler 901 Real Tube and Behringer VT999 with the 12au7..) and play mostly with Joyo emulators in front with a delay and reverb pedal -- that's about it these days. Powerful, small, simple.

    Edit: Oh, I have 3 other speakers to choose from. That's just the small one. :)
     
  12. marshman

    marshman Poster Extraordinaire Silver Supporter

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    I scored a pair of Eminence 820Hs for ridiculously low money on eBay in the last year and was hoping to convert a 1x12 into a 2x8, but all my cabs have glued-in baffles. Just mentioned it for your shopping/
     
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  13. printer2

    printer2 Poster Extraordinaire

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    Hate you. I have a number of 8" speakers pulled out of ceilings, not JBL though. The line transformer could be used for a low buck Push-Pull tube amp.

    A quick search found this.


    "Looking at the JBL data:
    - the Q is pretty high at 1.57;
    - The fs is high at 95Hz
    - there appears to be a 10dB rise in output above 2kHz

    I would not expect too much from them though, loading (box / reflex) willstruggle to deal with the T/S characteristics, and you will likely find the rising response is a lot messier than the graph JBL provide!"

    Sounds like it would be ideal in an open back cabinet.


    On to the OP's search. I would also mix two sets of speakers as long as they are reasonably close to the same SPL for both. Give much more of a surround sound effect.
     
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  14. NSB_Chris

    NSB_Chris Tele-Meister

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    While I was typing others were typing also!
    Also finding more options as I look further.

    So now I have:

    Weber "Ceramic Signature 8" (15W)
    Weber 8VF (60W)
    Weber 8F125 (20W or 30W)
    Jensen C8R (25W 93db)
    Jensen MOD 8-20 (20W 93.2db)
    WGS G8C (20W 95.8db)
    Celestion "Eight 15" (20W 95db)
     
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  15. Boreas

    Boreas Friend of Leo's Silver Supporter

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    I have always wanted to try an 8" and a 12" in the same cab. Or possibly an 8x8x12". Awaiting your results! Also waiting on wood prices to come back down...
     
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  16. NSB_Chris

    NSB_Chris Tele-Meister

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    Started looking up some more information. Never figured the Celestion was going to be an option and I think I am not going to strongly consider the expensive versions, which may be a mistake, but I think for this test I would like to keep the cost down.

    In consideration:
    • Weber "Ceramic Signature 8" (15W) $42
    • Jensen C8R (25W 93db) $41
    • Jensen MOD 8-20 (20W 93.2db) $40
    • WGS G8C (20W 95.8db) $50

    Not now:
    • Weber 8VF (60W) $87
    • Weber 8F125 (20W or 30W) $87
    • Celestion "Eight 15" (20W 95db)
     
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  17. ThermionicScott

    ThermionicScott Poster Extraordinaire

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    If you haven't started cutting any of the boards yet, have you considered making it a slant cab? I've always thought a little slant cab with 4x8" speakers would be cool, but never got around to building it. ;)
     
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  18. NSB_Chris

    NSB_Chris Tele-Meister

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    Cab dimensions are wide open at this point!
     
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  19. jsnwhite619

    jsnwhite619 Friend of Leo's

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    The Jensen C8R sounds great as a full range speaker. I have two in an old acoustic cab right now with a 20W stereo hooked up to my iPod on the back porch. Best sounding stereo I've ever owned. One of the guitar magazines did an 8" speaker shootout and you can find it online for the results.
     
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  20. printer2

    printer2 Poster Extraordinaire

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