Latency

    Actually the System boot does nothing else then resetting the system data cache. Looking at the number of bugs (monitor out, return volume, pops...) resolved by this simple operation, the problem could be there....the cache not resetting by shutdown and multiple addressing by the following boot...just thinking out loud here... :huh:

    "Music is enough for a lifetime, but a lifetime is not enough for music" Serghei Rachmaninoff


    Maybe my ears are tricking me, but after I have upgraded my unit from 1.0.0 to 1.0.5 the latency did not decreased automatically. I had to do a system initialisation. I have not had enough time to test or measure it, but this was my impression.

    Quote from DanielRigler

    Maybe my ears are tricking me, but after I have upgraded my unit from 1.0.0 to 1.0.5 the latency did not decreased automatically. I had to do a system initialisation. I have not had enough time to test or measure it, but this was my impression.

    Yes, your ears tricked you. There is nothing that can be "resetted" regarding latency.


    Timo

    Quote from Guitartone

    There is no latency.
    Next question


    this is an arrogant answer.


    There is a noticable minimal latency. And now its 6 months later now.
    You will recognize it especially when you play clean jazz or blues solo tones.
    The feeling when you play is just not there, the sound is good though


    If you play heavy chords it is not as annyoing

    Quote from Guitartone

    Yeah, right, it feels terrible. :rolleyes:


    You like to post "clever" replies, or what?
    Ok, you got thousands of posts...well well


    Maybe other players have a different sense for "feeling".
    So please, no need to get sarcastic.


    No one says the Kemper Amp feels "terrible", but it does not feel as good as a real amp.
    Its great for you if you don't "feel" a difference, but others do,
    Accept it !

    My Kemper has the same exact feel as my Marshall tube amp so maybe something is wrong with your setup?

    No, I feel a difference between my KPA and my amps too, it's ever so slightly less immediate, I'm not sure if there can be a solution as you need a certain amount of time for ADC, processing and finally for DAC, but it is there. The KPA has a measured latency of around 3.75ms however I've not tested that on the latest firmware to see if that's changed any. To put that in perspective it's the equivalent of putting the amp about 4ft further away from where it is right now, so it shouldn't really feel substantial, but I can concur that yes to me too there is a difference in feel and immediacy between the KPA and the real amp.

    Don't get so upset.


    In various previous threads about the same subject scientific facts about latency were posted.
    Like Per says, 3.75ms is like the amp being 4ft away from you...yet when playing 'live' guitarists don't complain about the latency of their amps, or the latency of the instruments of the other members of the band being 20 or 25 ft away.


    I agree, we must accept it, but it's not a bad/negative thing that needs to be discussed over and over again.

    When I'm in Profile Mode then I feel a difference too - as soon as I switch to Browse Mode all is fine here.


    Some use the KPA via a soundcard, digital mixer or digital studio monitors (with inbuilt DSP) - which may add additional latency.


    And yes, for the test switch off the noisegate.


    I found that sometimes my profiles sounds like having more latency - in some cases is then the bass part not captured good enough - try another mic or mic placement.

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    Quote from Armin

    When I'm in Profile Mode then I feel a difference too - as soon as I switch to Browse Mode all is fine here.

    This makes sense. Like it had been stated several already, don´t underestimate the additional latency the the digital conversions will add. Since every conversion will add 1 to 2 ms of latency, this can quickly build up to a chain of minimal latencies which might get noticable. The ideal signal chain regarding latency would be:
    Guitar - > KPA -> SPDIF -> Interface -> Speakers. This way you would only have two conversion in total, one at the KPA input stage and one at your interface output stage before your speakers.
    In Profiling Mode you add additional conversions. It even gets worse if you use the KPA analog outputs which add another 2 conversions at the KPA output and the interface input.
    I did a quick test once, if the SPDIF conncetion of the KPA will result in a lower latency. Please check this screenshot:
    [Blocked Image: http://dl.dropbox.com/u/5902643/latency.jpg]

    Quote from tylerhb

    don´t underestimate the additional latency the the digital conversions will add.

    Yep! Guitar > KPA > active speaker is only two conversions - no problem with that. Now if you hook up a digital effect into the effects loop this will add up to 6 conversion stages in total!

    www.audiosemantics.de
    I have been away for quite a while. A few years ago I sold my KPA and since then played my own small tube amp with a Bad Cat Unleash. Now I am back because the DI-profile that I made from my amp sounds very much convincing to me.

    Quote from Per

    The KPA has a measured latency of around 3.75ms however I've not tested that on the latest firmware to see if that's changed any. .


    Having been in contact with support months ago about the now fixed bug of unnecessary high latency that 3.75 seemed a bit high a number. So for the hell of it I did some measuring with the latest public beta FW. [Blocked Image: http://kemper-amps.com/library/wcf/images/smilies/wink.png]


    Disclaimer – BORING AND REDUNDANT STUFF


    I recorded 3 tracks simultaneously:
    - from KPA direct out to analog in of my interface
    (only one AD conversion in signal path),
    - from KPA SPDIF out to SPDIF in of my interface
    (one AD conversion + KPA processing in signal path)
    - from KPA analog main out to analog in of my interface.
    (AD + KPA processing + DA + AD in signal path)


    Using the direct out track as a baseline the track using SPDIF was delayed about 1.65 ms and the track using analog outs was delayed about 2.5 ms. So these numbers don't include the one AD conversion that's common to all of these - that could be maybe around 0.5 ms looking at the difference between analog and SPDIF signals? Anyway, quite low numbers I guess. And I feel all nerdy now.


    So what does this mean? Not much else than maybe I could have spend my time better and maybe I did this measuring all wrong.
    If it feels good or bad is what matters, not these numbers. [Blocked Image: http://kemper-amps.com/library/wcf/images/smilies/smile.png]


    BTW this was with just the stack on – no gates, stomps delay/reverb. Don’t know if that would change anything.


    I have no issues with latency or feel.