Posts by tayholliday

  • KPA on the eBay

    <p>

    Quote from Zapman

    Sorry to hear that, tough sacrifice I'm sure. &nbsp;Hope you get one back soon!!

    </p>


    <p>Thanks Zapman. I'm hoping I can get some decent amp modeling software for recording, but not sure it can hang withe the KPA!</p>

  • mini KPA

    Quote from Will_Chen

    Only a small percentage of guitarists are interested in modeling


    With all the modeling products out there, I don't see how that could be the case.


    Quote from Will_Chen

    It will be a floor Kemper with a (fairly) full feature set

    .


    Sigh. I'd actually prefer a simpler unit with just profiling as I've got pedals which do the other effects better :-\.

  • mini KPA

    The feasibility of a low-cost small form-factor KPA can be solved by asking a simple question: would the DSP hardware in the Eventide stomp boxes or the Strymon boxes have enough power to run the profiling algorithm? My guess is if we compare the DSP specs, it won't be a problem. I'm assuming those boxes have quality front-ends that you can plug your guitar into. Those boxes are in the ~$500 USD range.


    This is a great opportunity for Kemper to capture a bigger market. According to the 2011 NAMM report, stomp boxes + floor multi-effects were nearly 2/3 of the signal processing market. Stomp boxes were trending upward. Rack processors, the other third of the market, were trending downward.


    Also, personally, its a product that I'd love to see!


    cheers
    - Taylor

  • S/PDIF vs. Main Out?

    I don't think there's much of an audible difference. I would say the SPDIF sounds slightly more present with more defined high-end in my setup, but I could be making that up.


    Using SPDIF will reduce your latency slightly because you don't have to go through a D/A and an A/D again. I haven't measured the latency but articles seem to say its around 1ms for two conversions, or roughly the equivalent of moving your speaker 1 foot further away.


    For me, the downside of SPDIF is that I have to slave the interface to the Kemper's clock, which just leaves only one sample rate option. And with some audio interfaces it can be kind of annoying to have to switch those settings around every time you want to use the KPA.

  • KPA as a stompbox

    You make some good points, Jimmyo. I do have a KPA and I think its great.


    I also have compact pedals which claim to have high quality converters (t-rex replica for example), and my apogee duet is pretty small too, so it seems like stuff can be made compact. I also have an Access Virus TI Snow, which is pretty compact and since its also made by Kemper, hopefully has nice components :)


    Quote

    people who like pedals generally don't love modelers (althought the KPA is not a modeler)


    And because its not just a modeler like the AM4, I think it would be more successful. The KPA allows you to start with an amp you like (your own) and go from there, rather than hoping a model fits your tastes. Because the KPA is a high-end product, I'm guessing pretty much everyone buying it already has various other effects in pedal form and so all the other effects included in the KPA are somewhat redundant (certainly this is the case for me).


    Consider the Eventide stuff. They already had fancy rack processors that did all kinds of stuff but cost a fortune. They put some of the most popular effects from those in pedal form and had successful products (I'm just guessing they've been successful since they have made 4 different models over time). They could have made cheaper rack units, but recognized that most guitarists prefer pedals.


    I really like my KPA, but I have to admit its form factor has been kinda odd for gigging. Even a rack version would make more sense because I could protect it with a case. There's the question of where to put the thing, and sometimes it ends up just sitting on stage and I worry about it getting kicked.


    Anyway, I think when designing a product its important to focus on its core feature(s) that differentiate it (i.e. profiling) and don't try to include every possible feature. Make it small, elegant, and polished. That's the Apple model.

  • KPA as a stompbox

    Quote from Jimmyno

    Consider that it's not just a DSP question as others stated.


    How is it not? Other stomps have all the necessary I/O (with the exception of a mic preamp... no biggie) and a similar enough UI. The only question mark is the DSP.


    By the way, where was this previously discussed? I can't find the thread.

  • KPA as a stompbox

    Bah, naysayers! :P


    There are plenty of stomp-boxes with DSPs in them that are affordable. This is just a question of whether the KPA modeling algorithm could be made to run on an affordable DSP.


    Also, if the profiling analysis phase is computationally heavy, it could be offloaded to a computer connected via USB.


    Don't assume that just because you paid a lot for the KPA, that the profiling can't be done on much cheaper hardware! Some products are low-volume, high-margin.


    That said, even if the Kemper stompbox couldn't be made much cheaper, I still think it would be a good product.

  • KPA as a stompbox

    Would anyone else like a stripped-down KPA as a pedal? I think it would be great, and a real money-maker for Kemper.


    I'm thinking roughly the size of the Eventide stompboxes.
    No effects other than profiling.
    A bare minimum of I/O (in, out, profiling loop, midi, usb). Mono only.
    Very simplified UI.


    I think this form factor would be very appealing to the guitarist who just wants to bring a pedal-board to a gig.


    cheers

  • KPA aliasing experiment

    Per,


    Could you link me to your spectrographs? The other thread is really long and I was having trouble finding them.


    I would expect harmonics to be in the output signal. But what you see in my graphs aren't harmonics -- there are frequencies generated below the fundamental. If you feed either the KPA or Amp Designer a lower frequency sine wave, all you see are harmonics in the analyzer.

  • KPA aliasing experiment

    Hey,


    I saw a thread a couple days ago about aliasing in the KPA, so I tried some test signals using a S/PDIF loop. The KPA is running a simulation of my Elmwood Modena. I'm using the latest stable firmware. Everything seems good until you get up to about 8kHz, and then it starts to alias. Here's the input (8.6kHz sine wave):


    [Blocked Image: https://dl.dropbox.com/u/45540223/KPA-Input.png]


    And the (aliased) output:


    [Blocked Image: https://dl.dropbox.com/u/45540223/KPA-Alias.png]


    Now, here's the same test signal run through Logic's Amp Designer running some lousy-sounding emulation of a Mesa Rectifier:


    [Blocked Image: https://dl.dropbox.com/u/45540223/AmpDesigner-Alias.png]


    Also aliasing.


    I've been teaching myself DSP lately, so I find aliasing interesting. Is a high-gain amp model so non-linear that its hard to avoid aliasing?