Noob here | How do I connect 4 Kemper Kone speakers ?

  • Hey all,

    So I went and had my 4x12 Kemper Cab re-wired for 4 ohms through a tech and tested it out tonight. I wanted to test it at high volume and was around the 250 watt mark and after about 30 minutes, it started to cut out and I am not sure why.

    I posted a video of the sound cutting out so you can hear when it happens and what it sounds like.


    The cab is 800 watts (4 Kemper speaker), the Kemper Power amp is 600 watts. I had the power Amp boost at +6 to add a bit more volume and figured, this should be fine since I am well below 600 watts use of the power amp and well below 800 watts in the cab.

    Is there perhaps a specific setting in the output section or anything that might not be set correctly? The cab itself is wired correctly, so it must be the Kemper. I also haven't updated the Kemper yet to latest software. Could this fix the issue?

    Thank you for your help!

  • From the Main Manual:

    "At 4 ohms, the wattage is electronically limited to 600 watts. If these 600 watts are exceeded, the power amp is deactivated for a moment, which will result in a short dropout. It would require insane volumes for such dropouts to occur — however, if you are connecting a 4-ohm cabinet, you should test it carefully to ensure that your loudest signals stay below that critical level."

  • Right, so the wattage meter was around 250 watts when it dropped out, not 600 watts so this is why I’m not sure I understand .

    The manual says 600 watts for sound to drop out, not 250 watts.

    also how can the sound ever go more than 600 watts when it’s designed for 600 watts max?

    what is the point of the power amp boost if that function can potentially put our amp in danger over 600 watts?

  • Ah ha.. The wattage meter I believe is calibrated for 8 ohms so you are probably pushing 500 watts and occasionally exceeding the amp's power rating just by the odd brief spike that isn't showing on the meter.

    Dude, seriously turn your amp down unless you want to be another old rocker with hearing aids :wacko:

  • Well that explains a lot! 😂

    The main reason for me wanting to push the volume is our guitarist is going through a 120 watts 2x12 mesa , turned up only half way and he is always louder than me even when I am close to max volume on the kemper .

    I’m wondering if I increase the rig volume a bit and leave power amp boost off, that I’ll still be at a safe volume and still get a bit more volume if needed.

    I’ll test things out again tomorrow and see what happens.

    I noticed that cut out only happened during clean tones and not distortion with power amp boost at half way.

  • Makes sense, remember 100w tube volume equals roughly 1000w or more solid state volume (not sure on the exact ratio there, but that's about right)

    1 watt is 1 watt no matter what the source (tube, solid state, steam power.....)

    The reason people often say tube watts are louder is simply the way max power is measured. Power is measured at the point of distortion. I think it might be 5% THD but I’m not sure. Anyway, tube amps start distorting long before they reach maximum level. On the other hand solid state amps stay clean until very close to max output then clip badly. Therefore, a solid state measuring 100w is pretty close to maximum volume while a tube amp typical has more volume left after distortion becomes measurable. The difference shouldn’t be anything like 10:1 though.

    i would guess the volume difference between Derik’s Kemper and his bandmate’s Mesa 212 is down to speaker sensitivity rather than power amp output.

    I can’t find a sensitivity number for the Kone but the K12H which it is based on is 98dB. Whereas the V30 in the Mesa cab is 100dB. That 2db extra efficiency will make a significantly greater difference than a fe hundred watts power output.

    As Derik already found out, the meter is calibrated at 8ohms so he is really putting out around 500w average and peaking well above this. If that isn’t loud enough everything else needs to turn down instead of the Kemper turnIng up. At that level you should be well into the range of serious permanent hearing damage. Take that from someone who spent years thinking it was cool to blast a dual rectifier at stage volume even when practicing at home on in rehearsals. The constant ringing from tinnitus isn’t funny of cool. By the way, I even wore hearing protection for much of that time but that only reduces damage it doesn’t stop it completely. Plus there was already some damage done before I started wearing Custom fitted ear defenders.

  • Hi Wheresthedug, I'm referring to perceived volume vs watts, not watts vs watts. I think it's more like 100w tube volume requires 2000w solid state actually, I believe it's a case of more headroom required to avoid unwanted distortion iirc.

    Here's a link for an interesting interview with the guy responsibe for Blackstar amps where he mentions the topic:

    This is a 4 part interview, I believe it is part 2 where he discusses the relative differences in volume

    Agree about telling your band mates to turn down, going deaf isn't cool

    Edit: it seems I may have exaggerated slightly, according to the video I just linked it's more like 250w solid state would be required to match 100w tube volume for a similar frequency but with plenty of other variables

  • From an article

    Doubling Power vs. Doubling Output

    A common misunderstanding when it comes to audio is that doubling power (watts) will make it sound “twice as loud.” Doubling the power (or cutting it in half) actually provides very subtle changes to SPL levels. It will take a significant increase in power to sound "twice as loud". Lets take a deeper look into what increases in power are needed to make changes in SPL.

    A 1 dB change in sound pressure level is the smallest difference perceptible by normal human hearing under very controlled conditions, using a pure tone (sine wave) stimulus. A 1 dB change in level is very difficult to hear when listening to dynamic music.

    To produce an increase of +1 dB you need to increase power (watts) by a factor of 1.26. So, if you are getting 102 dB SPL from 100 watts and you want 103 dB SPL, you will need 126 watts of power. To produce a decrease of –1 dB you need to divide the reference power by 1.26, so you would reduce power from 100 watts to 79.4 watts.

    A change of 3 dB is accepted as the smallest difference in level that is easily heard by most listeners listening to speech or music. It is a slight increase or decrease in volume.

    To produce an increase of +3 dB you simply need to double power (watts).

    So, if you are getting 102 dB SPL from 100 watts and you want 105 dB SPL, you will need 200 watts of power. To produce a decrease of –3 dB you need half the power, so you would reduce power from 100 watts to 50 watts.

    Since this 3 dB plateau results in such a happy ratio, it is a very useful relationship to memorize:

    “2 times the power = +3dB...

    1/2 the power = –3dB”.

    A change of 6 dB is accepted as a significant difference in level for any listener listening to speech or music. It is a quite noticeable increase or decrease in loudness.

    To produce an increase of +6 dB you need to increase power (watts) by a factor of four. So, if you are getting 102 dB SPL from 100 watts and you want 108 dB SPL, you will need 400 watts of power (it adds up fast, doesn’t it?). To produce a decrease of –6 dB you need to divide the reference power by 4, so you would reduce power from 100 watts to 25 watts.

    This 6dB plateau also results in happy ratios that should be memorized:

    “4 times the power = +6dB…

    1/4 power = –6dB”.

    A change of 10 dB is accepted as the difference in level that is perceived by most listeners as “twice as loud” or “half as loud”.

    To produce an increase of +10 dB you need to increase power (watts) by a factor of 10. Yes, to get twice as loud, you need ten times the power!!!

    So, if you are getting 100 dB SPL from 100 watts and you want 110 dB

    SPL, you will need 1000 watts of power. To produce a decrease of –10 dB you need to divide the reference power by 10, so you would reduce power from 100 watts to 10 watts.

    The 10dB Rule should also be memorized:

    “10 times the power = +10dB...

    1/10 power = –10dB”.

    Here is a handy summary table which also lists the change in voltage and speaker excursion for each change in level:

    Increases in Power / Voltage / Decibels:

    1.26 x power (watts) = 1.12 x voltage/excursion = +1dB

    1.59 x power (watts) = 1.26 x voltage/excursion = +2dB

    2.00 x power (watts) = 1.41 x voltage/excursion = +3dB

    2.52 x power (watts) = 1.59 x voltage/excursion = +4dB

    3.18 x power (watts) = 1.78 x voltage/excursion = +5dB

    4.00 x power (watts) = 2.00 x voltage/excursion = +6dB

    5.04 x power (watts) = 2.24 x voltage/excursion = +7dB

    6.35 x power (watts) = 2.52 x voltage/excursion = +8dB

    8.00 x power (watts) = 2.83 x voltage/excursion = +9dB

    10.0 x power (watts) = 3.16 x voltage/excursion = +10dB

    Decreases in Power / Voltage / Decibels:

    0.79 x power (watts) = 0.89 x voltage/excursion = –1dB

    0.63 x power (watts) = 0.79 x voltage/excursion = –2dB

    0.50 x power (watts) = 0.71 x voltage/excursion = –3dB

    0.40 x power (watts) = 0.63 x voltage/excursion = –4dB

    0.31 x power (watts) = 0.56 x voltage/excursion = –5dB

    0.25 x power (watts) = 0.50 x voltage/excursion = –6dB

    0.20 x power (watts) = 0.45 x voltage/excursion = –7dB

    0.16 x power (watts) = 0.40 x voltage/excursion = –8dB

    0.13 x power (watts) = 0.35 x voltage/excursion = –9dB

    0.10 x power (watts) = 0.32 x voltage/excursion = –10dB

    As mentioned above, a +10dB increase in SPL is considered "twice as loud" and to do so power will need to increase by ten times.