Posts by OneEng1

Quote from daddo

Hi people, i've bought KPA and i'm very satisfied with it except... In the perform mode I get a lag when swiching between channels. For an example if i want to change from channel 1 to channel 10 i can't do it fast because i don't actually see the channels changing - if i press the button several times I get to the desired channel if i count how many times i've pressed it. Or i have to do it slowly and wait untill it loads the next channel. Do you have the same problem? Cheers

What MIDI pedal are you using?

Even more stuff to try!

So many good sounds!

Thanks again guys.

Quote from Pentafox

Hi guys,

Tonight I discovered a problem with both of my expression pedals on my FCB1010/Uno4Kemper.
For some reason I didn't use my pedals a while but for the rehearsal tomorrow I just got my rack in working orde….. well, except for the pedals..
The pedal-repons is very slow. The volume acts like a swell effect and the way is also very sluggish.
I run the latest firmware on the Kemper.

Any idea's?

Thnx,
Pentafox

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I don't have any GOOD ideas, but I have some ideas.

First, make sure your FCB1010 firmware chip is securely and properly inserted into its socket.

Next, make a backup of your entire kemper, then ask someone who knows more than I do how to restore the Kemper to its factory default. Once you have done that, see if you still have the problem.

I use this setup (as many others do) and I have very little delay in rig changes.

Thank you guys so much! You are great. I'll have my rig back home early next week and will definitely give all these a try as well as tweaking the definition and clarity parameters as specified!

Hi guys,

Before anyone asks, I did try to search around before I posted this as I didn't want to duplicate other posts if the information was already in here

I gig with a pair of Fender American Strats. One has Lindy Fralin pickups in it, and the other has Kinman noiseless single coil pickups in it.

The former is a more traditional sounding single coil strat sound, while the latter is more bright and jingley sounding (is that actually a word?).

I have need of a few different sounds as I go through covers in my band. I have some really good sounding cleans that work for me, and one Recto patch that covers the really high gain stuff nicely.

Where I seem to have problems is in the catagories of:

• Slightly pushed light breakup
• Mid pushed with more breakup
• Classic rock Marshallesque AC DC tone

I have found that the stock patches don't give me what I want/need in these areas and would like some suggestions for some commercial rigs I might give a try for these purposes.

I have noticed that the classic rock tone specifically seems to be the domain of humbuckers. I suppose I could just break down and buy a new guitar, but I thought I would try this first.

Any suggestions?

I am an EE, so I don't recommend the things that I am comfortable with to just anyone; however .....

I have been looking into this as well and my thought was as follows:

1) The easiest cable to construct which is the least risky would involve 2 MIDI cables, and a DC power cable rolled into a 1/4" plastic conduit.
2) Moving to more user friendly, but more risky would involve a modified MIDI cable for the MIDI IN and an unmodified MIDI cable for the MIDI out. The MIDI in would have both the MIDI signal pairs AND DC power and ground which would require a mod to the internal powering of the FCB1010. If you did all the mods internal to the rack side and FCB1010 side, you could use standard 5 pin MIDI cables.
3) A setup like what was linked to in this thread involving a 7 pin arrangement which houses both the send and receive signal pairs as well as power and ground (6 pins total). In this setup you also need to modify the power input in the FCB1010 as well as the modifications needed in the rack to create the signals from the kemper and DC power supply to the 7 pin connector. This setup requires the most work, but results in the most convenient live setup IMHO.

Keep in mind that it is very possible to break your Kemper and/or the FCB1010 if you mess this up and there are many ways to get it wrong.

I was able to find schematics for the FCB1010 and a video on how to hard wire the modification.

Does anyone know if the aliasing reported by some people has been fixed? Between the faster switch times and this fix I will be anxiously awaiting this update to be released!!!

Thanks Kemper!!!

Welcome!

I am am sure that the Kemper is going to be a huge step up from the Line 6 gear

Quote from ckemper

The improvement of the rig switching time has always been on our todo list. Since other important features are about to be finished, this topic has rised to a top position on the list

While I am personally doing fine with it the way it is, there are obviously others that have a different usage model (metal band and the only guitarist) that it is really causing an issue for. In an otherwise nearly perfect product, it is nice to know that you and the others in your company are still on the ball with continuous improvement of the already fantastic product!

Thanks for being there for all of us Kemper users out here

I still feel like this was some of the best money I have ever spent on a piece of gear. I suspect I will always feel this way!

Quote from Quitty

A quarter of a second is staggeringly long, actually. At 120 BPM, that's almost a whole eighth note

I would agree that less would be better, but I have had no issues with this live. I play covers and there is another guitar player in the band, so perhaps our usage models are different.

My digital mixer (X32 Rack)! I have gone from a ton of outboard gear and a huge rack full of crap down to a single 6 space roller rotorack and an iPad that mounts on my mic stand. I get multi-track recordings through USB to a laptop and stereo recordings directly to a USB stick.

Another big winner for me was going to an IEM system instead of wedges.

In fact, it was the huge change in size and weight that I got from going with a digital mixer that prompted me to look into the status of digital amps.

I (like most of you) had always found that the only way to get the sound of a tube amp was to use a tube amp. I ran across someone raving about this .... Kemper thing

I can't see ever going back to EITHER an analog mixer, OR a tube amp!

My back is in total agreement with me

I feel better knowing that the German team that beat the US team also bested everyone else to win the World Cup

Congratulations to Germany on their great performance!

I get ~200mSec. The top trace is a recording of going from a clean to a heavy rig. The bottom trace is a microphone sitting on my FCB1010 using Uno4Kemper v1.3. I cut the image a bit too soon. Just beyond the right of the screen you would have seen the sound of the switch going back up .... so the Kemper switched faster than my foot went from down to up on the pedal board.

I would prefer it be faster, but this has not been an issue for me gigging the last couple of months.

Note the complete lack of any glitches, spikes, or dead line between the rig change.

[Blocked Image: http://www.mtomidnight.com/images/kemper_delay.jpg]

Quote from PBGas

The biggest issue is with shipping. By the time I end up with this, it will cost more than my footboard. Not much one can do about it though.

Same problem here

I am now very intrigued with the idea of a single cable connection though. It is my biggest complaint with using the FCB1010 with the Kemper.

Quote from Behind

Thank you for the info!

I made the test myself by pressing left and right soft buttons of the "arrow" to change between performances. The results are quite strange...

Here is the audio: https://mega.co.nz/#!DFIUnaqJ!p6_lnGzKghZaaILRUUJKfl8xWZ9xYEYqmrGbkItH6ms

What you hear is me changing from slot 3 to 4 and then 4 to 3 repeatedly. Performance 3 is KM-COSMOGENESIS and Performance 4 is the same profile but with a Hyper Chorus loaded. So I changed between the same profile to see if the delay time improved but it didn't help at all.

The first and second times I changed from 3 to 4 I got an approx delay of 250 ms BUT the 3rd time I did the same, I got a delay of 450 ms ( ). So the delay is not consistent after all, which makes things even worse. I mean, if I know that I have to measure half a beat to land correctly in the next bar... How can I do it if the delay I am getting is not consistent?

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Interesting.

I never got anything above 200mSec and never anything as extreme as 450mSec.

What version of firmware are you using? How many rigs do you have in your library? What are you using for a footswitch and what version of firmware is in your footswitch?

I think that 450mSec would bother me quite a bit! 200mSec is just "OK".

I measured the time from the middle peak of the "click" of the foot switch to the point where the next patch visibly picked up. The latter was easy to pick up on since there was a very small blank spot right before it of 10mSec.

I could hear your switch times in the recording and it sounded like a long time to me too.

Laimon,


I never take it for granted that people understand concepts like digital aliasing. I didn't intend to imply that anyone in particular didn't understand it, I just wanted to make sure that people that haven't ever created a digital algorithm or been forced to wade through the calculus needed to solve equations associated with time to frequency domain still had a point of reference in the discussion.


I am sure that you have produced a very valid test case that proves there are artifacts created by your profile. I have heard them and agree. I am just pointing out that there are several causes of digital artifacts. I am equally sure that the smart guys at Kemper amps are going to be able to fix it with the hardware they have chosen to design the Kemper profiler with.,

About 2 months here.

I am still learning about what free things are out there that I can use, and how to tweak them to my liking. With just free rigs and what came with the Kemper, I have the best sounding cover sounds I have ever had.

I am thinking pretty seriously about some of those TAF rigs now.

I play every night. I just can't get enough of the pure tone I get through the Kemper. There is nothing like it that I have ever even heard of before.

I have nothing but good things to say about the Kemper. In fact, I am going to play a little more before I go to bed

Thanks Sam

I also spent a bit of time just playing through some of the covers we do to see how I use the foot switch in live use.

If you take the song "Kryptonite" by Three Doors Down as an example, what I found was that I tend to switch patches between strums. Since my strums are much longer than 200mSec, there is no discernible delay in the performance. I also have another guitar player in the band, so unless I switch patches really badly, I have cover from the other guitar player to keep any dead space covered up on my end. If I were the only guitar player things would have to be much more precise I imagine

Data is always good to have.

Lets not get too carried away with the ultra high frequency stories here. I personally can not hear anything over 15Khz period .... but young people (who don't play in bands) and dogs can

While it is true that a guitar (and certainly a guitar and a stomp box) can generate frequencies that are quite high, most guitar cabs can't reproduce the frequencies. Here is the spec sheet on the ever popular vintage 30: http://celestion.com/product/1/vintage_30/

You aren't going to get much over 15KHz out of this speaker no matter what you put into it.

As for aliasing, it isn't caused by the A/D or D/A in the real world. All modern A/D converters are capable of sampling at very high frequencies (>192Khz). If you study electrical engineering (I am an EE myself), you learn that you can digitize a signal by sampling it at discrete points, processing it into the frequency domain, then changing it back into the time domain and feeding it into a Digital to Analog converter (D/A) to output the voltage EXACTLY like it was before you digitized it ....... as long as you sample 2 times as fast as the highest frequency you wish to reproduce.

There is a long drawn out mathematical explanation for this if you care to look it up you will find reams of gibberish explaining it in detail

So, sampling at 44Khz would give an effective reproduced frequency ceiling of 22Khz ..... which is higher than most humans can ever hear even at birth ..... and much higher than any guitar cab I have ever heard of being capable of reproducing.

Now what DOES cause aliasing in the real world is down sampling in order to reduce processing, or mistakes in the DSP signal paths which result in a time alignment issue that results in something that sounds like aliasing.

My educated engineering guess is that what we are hearing in the Kemper is the latter .... and it can be easily fixed by modifying the DSP code to better align things internally.

I doubt that the Kemper is processing bound.

Most guitar cabs have speakers that have a cut-off frequency around 5K Hz. That is what we are all used to hearing with a tube amp.

That isn't to say that there aren't some frequency content above 5K when you play through them, only that it doesn't get through at nearly the volume that it comes in at.

At 10K, I would say you are pretty safe, so a sample rate of 20K and processing capable of handling the samples at this rate should effectively eliminate aliasing associated with guitar frequencies IMHO. That shouldn't be an issue for the Kemper. While I haven't opened one up to see what parts are being used in the Kemper, I can say that the X32 digital mixer is using the 3rd generation SHARC DSP processors which are capable of processing 38 channels at 48Khz through the entire efx chain with only about 1.8mSec of latency total. I am guessing that the Kemper can handle a single channel input and process it without any aliasing using its Symphony 56721 Family processor...... no problem.

I have noticed the aliasing in notes high on the fret board on the high E string on my strat on several rigs.

I will be looking forward to the fix for this.