Posts by RosboneMako

    I can certainly see a use for it and benefits from having it HOWEVER, I'm not sure how such a thing could be implemented.


    Agreed. Sounds like a great idea. It would be a lot of work to implement.


    And sometimes a small change in EQ makes a huge difference. Sometimes not. Like a few dB change could be huge, but may be unnoticable in the small scale EQ diagram.

    When I first got my Stage I profiled all the time.


    Sometimes I would check the sound before doing the refining stage. Occasionally I would turn down the volume to test the profile. Then I would refine. I got all kinds of weird results. It blew the Kempers mind.


    But thats me. Never doing things the correct way 8)

    I also wanted to say you can use any IR/CAB from any profile on the Kemper. You can drag and drop the CAB in RIG MANAGER. I have LOCAL folders setup to store IR/CABs in RIG MANAGER.


    So a good place to start looking for good IRs is in the free KEMPER PACKS in RIG MANAGER. These are usually the better profiles made by the better profilers with great equipment. Meaning they are done in a studio with great setups and should give you great results. And since you can search by artist, etc you can narrow down the type of IR/CAB you are looking for.

    This is a hard topic to discuss. An IR is basically an EQ setting. Since EQ settings can vary and will only apply to a certain tone, saying a certain IR is good/bad is up to interpretation.


    The intangible thing to an IR is it is NOT just an EQ. It is an EQ based on time, not just frequency. The time portion is the echoes of the sound in the cabinet, room, etc.


    1) Some IRs are calculated from a frequency sweep of the speaker/setup. These sweeps will remove some of the time portions of the IR.

    2) Other IRs are made by sending a pulse thru the speaker setup. This method captures the time portions of the IR.


    I do not know which method the Kemper uses. You can hear the impulse 'click' sound during a profiling process.


    A really good IR, will be calculated so as to remove the time portion.

    A really good IR includes the time portion so it sounds like it is in a tunnel or small room.


    These are both valid statements.


    TLDR

    To say certain IRs are good would require you to say what type of music you are playing, how much gain, and what type of speaker system you are using to hear the IR.


    IRs without much bass will fit into a mix better.

    IRs with a lot of bass sound better while playing them.

    IRs with too much highs will sound shrill and fizzy for rock but great for cleans.

    IRs with too much highs will sound good at low volumes but are ear piercing at high volumes.

    PERSONAL OPINION

    I do not play super high gain stuff. But I tend to push Clarity up to around 2.5 max on a Marshall type sound.


    As I am tweaking a sound, I ALWAYS find what ever changes I made are better. But they are not. They usually make it worse. Clarity is one I find that I always over tune for high gain stuff. Usually .5 to 1 max is better and 0 is best. But again, this is for a Marshall level tone. I have never set Clarity enough to get crackling, could maybe be clipping somewhere since Clarity may be adding dynamic range to the highly compressed tone. The change in dynamics is what makes it feel/sound better to me.


    It is best to use a Looper while tweaking. I tend to play differently after a change which tricks my brain into to thinking it is better.


    I think the key to M.Britt profiles being popular is he tunes them for high volume thru a PA (and probably has good ears). Using this method hits a sweet spot that works for most Kemper user situations. I know I tune my stuff to low volume studio monitors and assume they are probably really harsh at high volumes. So I would expect a wide variety from profiles.

    Thank you both very much! @RosboneMako Your response was great! I feel much more confident on being able to do IRs. I feel like that was a full blown lesson on them!

    The Kemper was my first experience with IRs and I went down a rabbit hole for a year or so just bathing in IR possibilities. So I am no expert, I just have a lot of experience messing with them in not so normal ways :)

    Best of luck on your adventures!

    Most profiles come off a mic'ed amp that is not producing much sound below 100-120 Hz. That is where you get the thump.


    In my studio for jamming fun, I use a STUDIO EQ and set the lowest EQ to 180Hz and dial up the gain on that band.

    For a PA you may need less freq and gain.

    For a 4x12 cab you may need much more since guitar speakers tend to peter out around 100Hz. But all the thump comes from 100 and below.


    PROBLEMS:

    1) The freq you pick will vary with the speakers you are using. What sounds good on your speakers may sound like muffled garbage on a PA with some real bass response. So you are playing a dangerous game. You have enough rope to hang yourself.


    2) As people are saying above, in a band setting the guitar sits above the bass in frequency. The thump you hear in a song comes from the bass and guitar at the same time. By adding too much guitar bass, you will be fighting the bass guitar in a mix. If you and your bassist are not super tight it may make you sound out of time and muddy.

    So, if you want to send me your profile, I'd be happy to send you the IR of the cab.

    This is the 3rd and super easy method. 8)


    Since the person making the IR can deal with the specifics like turning off the AMP, pedals, etc to get the true CAB response. And be aware that the final IR may sound different since what you hear on the Kemper may include EQs from pedals, amp model, etc.


    Jonelli Which software are you using?

    There are a few ways to convert the CAB:


    1. The method you mention above sends an IMPULSE thru the Kemper and you record what comes out the other side.
    2. You download ROOM EQ WIZARD and you do a frequency sweep of the CAB and convert that sweep into an IR.


    Both methods work but require some software and knowledge to get thru.

    Room EQ Wizard (REW) is the easier method.


    REW METHOD

    1. Connect the Kemper input and outputs to your sound card.

    SC Out -> Kemper In
    Kemper Out -> SC In
    2. Open REW and in preferences select the correct Inputs/Outputs. Close the dialog.
    3. Click MEASURE on main menu and Continue anyway if asked about calibration.
    4. Click START.

    5. After the sweep is done you will be shown the freq response of the CAB. Select EXPORT IMPULSE RESPONSE AS WAV.


    You now have the IR, however, it is not in a usable format. You need to do some editing.


    1. Download GOLDWAVE audio editor or use the editor of your choice.

    2. Open the WAV file and trim off the extra space around the IR. You will want the IR to be a little bigger than 2048 samples.


    STUFF TO KNOW

    1. You may want your sound card in the correct mode that you want the IR to be in. ie 44.1 kHz or 48 kHz. The Kemper is always in 44.1 I believe, so you should be there already. This is not 100% necessary as you can pick the sampling rate in REW when you export.


    2. IRs are 1024 or 2048 samples long. You want the IR to start as soon as possible or you are adding LAG. So manually editing the IR is your best bet.

    At 44.1kHz you will want a minimum of (1024/44.1)=23.22 mS of audio for 1024 samples.

    At 44.1kHz you will want a minimum of (2048/44.1)= 46.44mS of audio for 2048 samples.


    3. You can play around in REW to see if you can set it up to trim off the extra space around the IR. There are some settings to try. But some times the IR will have oscillations before the actual pulse that you may want to trim off. And if you edit it manually you will learn what is going on more.


    4. Normalize the IR. This means make the IR as loud as possible. This can be done in REW when you export or in your audio editor.

    IRs are normally a large peaking pulse followed by oscillations. If you edit the IR and the phase gets destroyed, the IR may lose its peaky pulse and become a blob of oscillations. If normalized this blob will be 3-6 dB louder than the original IR.


    5. Once you have the IR in wave format, you can apply some EQ to it if needed. Depending on the EQ code being used, you may destroy the phase response of the IR. So your milage may vary.


    6. Some IRs are louder than others.

    The entire IR is multiplied times every sample of your guitar playing. IRs that adjust low freqs will have a large negative spike right after the large positive spike. This negative spike will make the IR quieter since you are removing some of the overall volume. That is completely normal and part of how it is supposed to work.



    EXPERIMENT

    You now have the means to measure IRs for anything. Speakers, other units, etc. In fact I wrote a program to let me draw the freq response and then I use REW to convert it to an IR (need to generate minimum phase response first).


    For speakers just use a microphone instead of the Kemper Out -> SC In.


    I got a cheap Chinese class D amp off Amazon and I have swept ALL of my speakers. Seeing the REW freq response will also teach you about proper micing techniques. Since you will see bad resonances and suck outs from the room, other speakers, etc.


    EXAMPLE FREQUENCY SWEEP

    Your Kemper sweep should look like this. The RED line is the freq response. The GREEN line is the phase. The phase normally has an instant change at the speakers resonance. Usually around 75 Hz for 12" speakers. The phase should not change phase everywhere. Normally around 75Hz and then again at a higher freq. If your micing technique is bad, there will be phase changes all over the place and the freq will have large dips as well.


    You dont need to know any of this for the IR conversion. Just hints to let you know you are the right track.


    IR EXAMPLE

    1. The image on the left is what an IR test pulse is. A single sample at full loudness in a WAVE file.

    2. Once that pulse goes thru your Kemper, you get a smoothed out oscillating thing (Right image).

    3. If you dont trim off the beginning of the IR (PINK) you are adding lag and altering the low freq response of the IR.

    When I got my Stage, I spent months on profiles and I came to a conclusion of "If I can play just about any song on it and it sounds good, that's a good profile". So for my tastes, a Marshall just works and could easily see myself playing the MBRITT 69 Marshall forever also.

    THOUGHTS:
    The guitar that feedsback may have microphonic issues. The pickup may act like a mic and pickup vibrations in the guitar? It may be potted differently for example.


    Another issue could be if it has a trem system. The springs themselves will start vibrating and this works its way up to the strings. I would assume a low to mid freq feedback from this. I dont play loud but I usually wrap tape around my springs to get them to not act like reverb tanks in my guitar. Pros probably have better tips like rubber bands, velcro straps, or something.

    The blackouts and the Amp Profile may have similar frequency curves. The peakier a frequency curve gets, the more prone it is to feedback. It takes less apparent energy to get it resonating because the energy adds up. Think like you are tapping a spring and it vibrates at a certain freq (Resonant Freq, Fr).

    The noise 100% sounds like PC noise. My gaming PC has a full glass side and this is all I hear with any gain at all.


    As others have said, you need to strip down to the Kemper and the speakers only. Everything else turned off.


    Electrical devices are radio transmitters. The only way to stop it is to encase the device in a metal box (Faraday cage). That is why computers are usually a full metal box. My PC has a glass side so it does not stop ANY of the Radio Frequency noise coming out of it. That is also why a guitars pickup cavity is sometimes taped off with copper/metal tape to create a faraday cage around the pickups and wires.


    If you still have noise issues with only the Kemper and speakers turned on, you need to turn off the noise gate and walk around the room with the guitar. RF energy is a distance squared function so you should hear the noise volume rise and fall as you move towards and away from the actual noise source in the area.


    The noise could simply be coming from the powered speakers themselves. Especially if you have done things to remove the ground from them by using hum eliminators, etc.


    You may also want to turn off any lights in the area especially if you have dimmers involved. LED lights and Dimmers chop up the low frequency power and turn it into RF energy that can be transmitted to your guitar (antenna).

    Apple is usually good about noise. That mini may have a plastic case that is not stopping the noise coming out of it. Or it may have an external power supply that is noisy especially if its ground is being removed by hum eliminators.


    TOO LONG DIDNT READ

    1) Everything is capable of putting out noise. Most likely a computer of some kind. PC, mouse, keyboard, other computing device (Alexa, phone, etc).

    2) Walk around with no noise gate to locate the actual noise source.

    funny you mention line 6! with the exception of the UX8, ive been using the UX series exclusively for all of my recording over the past (almost) 20 years. unlike the majority of Line 6 products, i have a real soft spot for them. the UX1, UX2, and the KB37 have been my rock-solid best friends. ^^

    The UX8 was the best thing I ever bought for guitar/recording. It did it all. Dual PODs, 8 channels, etc. It had vocal channel models, amp models, etc. I used it for everything. Until it died. Then I got a Kemper to replace it :love:

    I'm unsure why you think that, and I don't believe it is true. It may be true for you, but certainly not for 99% of users.

    My point was anecdotal. Windows does not seem to be as stringent with their drivers. Anyone can sell anything with any drivers. This creates an environment of "nothing is reliable". Your experience will differ greatly from manufacturer to manufacturer. This reaches into the hardware itself as well which ranges from good to barely works.


    If Windows drivers were easy, no one would have to run ASIO4ALL. Windows clearly has some issues with its sound design in general if it requires people to run some rando generated generic driver to get Windows to do a basic function. In fact looking at PROPERTIES on devices in Windows makes me question if they even tried at all. There are tons of properties and none of them are what the thing is. You get stuff like "Unknown Device", "Sound Device", or "Profiler". That is the hallmark of poor design.


    Most of the Windows issues I hear with games is sound related. Another thing that tries to play multiple sounds in real time. These may not be driver related in full, since many are "a person was behind me and I never heard them" type issues. Once again, something that is very simple to implement, but many cant do it.


    Apple seems to focus more on drivers and hardware. Their goal is to be simple and reliable. To me Apple should be the gold standard for audio because they seem to have better requirements. But most of the complaints I read on this forum are people with Apples. And stuff I read in other places seem to be "it works good, but dont run a newer OS than Ooga Booga 13". I have never run an Apple PC and I never would, so I have no experience here.


    Since you guys (Kemper) are actually writing drivers, you know much more than I do what the landscape is like.

    Well, Firewire worked for a little while. I had an Alesis Multimix 16 so I could record 8 mics at once for drums. I retired the PC it ran on and gave it to my young daughter. I finally dumpstered the Multimix because it would never run again. I tried PCs, laptops, everything I owned for a few years and it never worked again. While working on it I read that laptop Firewire chipsets were trash and they didnt work :wacko:


    I should have kept it because it still worked as a mixer. But I was so mad I just tossed it into the trash.


    So I bought my Line 6 UX8 (USB 2.0) and it worked flawlessly for many many years. Well the USB worked. The multiplexer on the input was terrible and I lost most of the channels over time.


    I only run my Kemper on Rig Manager USB. And it connects every time no issues. :thumbup:

    Please take the time Kemper to make good drivers. So few companies do that.

    Is it even possible to make good drivers? :/


    Windows is the wild west for reliability. And Apple seems to have more issues than Windows (which makes no sense).


    I Normally buy Behringer UMC404HDs and I have no issues. But I decided to buy another brand last time. It was heavier, had VU LEDs, etc If the CPU is busy at all...I mean at all... the audio warbles like you have a weird tremolo going. Tried various buffers, no joy.


    I always think of getting a more expensive interface until I read the reviews of "its bad.", "Crackles", "etc". Makes me wonder how good USB is. Then I remember my Firewire days and how that NEVER worked ever. And dont get me started on Bluetooth. I have never even seen that work on Windows.


    I have not tried the Kemper because I record a bunch of other stereo stuff like drums, keys, bass, mics, etc But some day I may have to test it for the giggles.

    Is this the new or the old DSL40? (sorry, can't remember when the new ones were release, so I'm not very specific here)

    I have not tracked the versions. I have the DSL40C. There was a popular ez to do mod people did on the C to get the channels more tonally balanced. I think Marshall included that mod on the CR version.


    I never spend money on equipment (because I am not very good at guitar). But I splurged and got the Les Paul Traditional (avatar) and the DSL40C on the cheap. I had an old JCM800 that I let go to a friend. So I thought the DSL would be a good replacement. Its ok. I still have it. It is no JCM800. But I only pull it out to make profiles on the Kemper when I get bored. I never use it.


    NOTE: I dont play loud. That extra high freq may be a good thing at volume. I will have to do some profiles some day. I have heard people say a TubeScreamer and the DSL are all you need for metal. Maybe they are playing really loud.