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Is there a way to measure speaker sensitivity?

Discussion in 'Amp Central Station' started by Jakedog, Jan 18, 2021.

  1. Jakedog

    Jakedog Telefied Ad Free Member

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    I have a Supro Blues King 12. I don’t mind the stock speaker. It’s harsh at first, but as it breaks in it really gets pretty cool. I’d like to use the amp a lot for gigging but I’m not sure it has the guts to do some of the stuff I do.

    The best possibility for making it louder with minimally invasive modding would be a more efficient speaker. But I don’t know what that is. If the stock unit is a 90-94db speaker that’s easy. If it’s already got a 99db speaker I may not be able to get any more out of it.

    There are no sensitivity specs listed for this speaker anywhere that I can find. The only information I can find is that it’s 8 ohms, 75 watts RMS, and is designed to sound like a 50’s field coil speaker while having modern construction.

    I don’t want to spend money on a speaker unless I can guarantee it’s gonna be louder.
     
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  2. northernguitar

    northernguitar Friend of Leo's

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    Do you have an efficient speaker to test it?
     
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  3. Jakedog

    Jakedog Telefied Ad Free Member

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    I don’t have another 8 ohm speaker. I have a 16 laying around, but that won’t work.
     
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  4. northernguitar

    northernguitar Friend of Leo's

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    It was a dumb question.
     
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  5. Chiogtr4x

    Chiogtr4x Doctor of Teleocity

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    Very dumb! ( kidding!)

    Why was it a dumb question?
     
  6. Jakedog

    Jakedog Telefied Ad Free Member

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    It definitely wasn’t. I’m famous for not thinking of the obvious. Just ask my wife. lol. It’s got me thinking maybe I can borrow one to experiment with...
     
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  7. VintageSG

    VintageSG Friend of Leo's Ad Free Member

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    There is a way to measure the sensitivity, but you'll spend more doing it than the cost of a different speaker. Accurate dB meters cost a lot, baffles are easy to build, but cumbersome and not much use afterwards. Signal generators are cheap enough to build, and a basic, true 10 Watt ( no clipping, hence 10x the required power ) Class D amp can be had for chump change.
    Write to Supro.
     
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  8. Musekatcher

    Musekatcher Friend of Leo's

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    I bet there's a sound meter app for your smart phone. Sensitivity may can be measured, if you can provide the input signal, which I think from memory is a 1000 Hz signal at 1 watt? And I think you read the noise floor first before you send the signal, then measure with the signal and take the difference and that's the sensitivity in db? On the 1 watt, I'm thinking you can measure the voltage and the current, and do a P=IV=watts? And there may be some conversion factors involved. Its doable with a multimeter.

    Or..

    You can compare with a known speaker with a published sensitivity. You probably can't scale a number, but you can tell if its less or more efficient/sensitive. Needs to be the same resistance speaker.
     
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  9. Addnine

    Addnine Tele-Holic

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    Let it watch an Oprah rerun: see if it gets all weepy.

    Well, anyway. I have one. The inbuilt speaker does improve markedly over time. But it is a very simple circuit, and the sound is a little unrefined. I'm not sure a different speaker would change that. Maybe I'll try to hook mine up with a 2x12 to see what the diff is. I'll get back to you if i do. (not sure, tbh, if there's a way to hook it up w/o a little rewire.)
     
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  10. Jakedog

    Jakedog Telefied Ad Free Member

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    Unlike myself, it had absolutely no reaction to “The Notebook”.
     
  11. suave eddie

    suave eddie Friend of Leo's

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    Maybe a dumb question, but have you tried contacting Supro to ask if they have any specs from the speaker manufacturer?
     
  12. Jakedog

    Jakedog Telefied Ad Free Member

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    I have an email out. They’re pretty tight lipped about most stuff though. So I’m not entirely optimistic.
     
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  13. Chiogtr4x

    Chiogtr4x Doctor of Teleocity

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    As you know, I have the BK 10 with same speaker design, just smaller
    What is the attraction/ characteristics of duplicating ( or similar) the old-style field coil speaker?
     
  14. Addnine

    Addnine Tele-Holic

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    Nope. It's my understanding that sensitivity ratings vary with testing protocols so much that comparing brand-to-brand is very iffy anyway. I'd hook it up to something you've got on hand and judge it that way. I'm actually pretty happy with mine after a lot of break-in, but I do undertsand your reservations. The sound is not as open and limpid as some amps. I do intend to set it up w/an external spkr jack. Not here at the moment, but I don't think it has one as it is. Easy to install one, but I haven't done it yet.
     
  15. schmee

    schmee Doctor of Teleocity

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    One of the problems with speaker sensitivity ratings (according to Ted Weber) is they dont all use the same standard.

    The best thing the OP can do is get someone he knows to test with with a known speaker I suppose. The fact that Blues Kings says they are wanting to emulate a field coil may mean that is an inefficient speaker, but it's just hard to know really. It could just be sales bru hah hah.
     
  16. Addnine

    Addnine Tele-Holic

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    I THINK (don't know) that they tried to mimic the sound, but that it is not actually a field-coil speaker. I'm hoping it's an 8-ohm spkr, so I can use it w/ my cab after I wire a jack in there. Any idea if it's an 8-ohm speaker?
     
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  17. uriah1

    uriah1 Telefied Gold Supporter

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    I have their bd10. Loud as heck. 90 watts. Like it a lot.
     
  18. BobbyZ

    BobbyZ Doctor of Teleocity

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    Yeah probably the easiest thing to do is plug into a speaker you know the db rating on and guess.
     
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  19. nojazzhere

    nojazzhere Doctor of Teleocity

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    The reason I know it was a dumb question was it was the first one that came to my mind. ;)
    @Jakedog.....do you plan to use any pedals? Perhaps a transparent "booster" would get you where you want? I have an LPB-1 pedal that I sometimes use for this purpose....not totally transparent, but close enough for R&R.
     
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  20. Chiogtr4x

    Chiogtr4x Doctor of Teleocity

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    My BK 10 (the 5 watt 6V6 one) is a 10" 8 ohm speaker.
    I think the 12" in the BK 12 is also 8 ohm
     
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