Posts by musicman65

sheguitarplayer,

GOOD NEWS! I got so pissed about the crappy signal to noise ratio on the GR-55 Guitar Out jack, I took my GR-55 apart and got my o'scope out and went noise hunting. Turns out the noise floor on every output is the same, identical...about 1mV avg pk-pk. It's on everything, headphones, L/R mains,,,,and guitar out. The issue is that the rest of the outputs have gain so the output signal is large in comparison to the noise floor....but the guitar out is just buffered with no gain so its a smaller signal. That makes the signal-to-noise ratio worse than with the main outs or headphones. In fact, the headphone out may be the best.....hmmm?

Sooo...I decided to use the L/R Main outs into the Return/Alt Return jacks on the KPA and set the first stomp to Stereo Loop. This injects the GR55 into the KPA signal chain just after the front guitar input and noise gate, It works great. Quite too. You lose the noise gate (and maybe the Clean / Dist Sense?) but gain a full guitar modeler with alt tuning, tons of effects, all the Roland Goodness of the VGuitar setup.

Now, here's the cool part. After saving your KPA profile with Stereo Loop enabled in the Stomp section, disable the stomp and save a second rig with Stereo Loop in the X slot of the effects section. Now dial up a PCM synth tone and it's inserted in the mix AFTER the Amp section....nice and clean. With Stereo Loop in either Pre (Stomp) or Post (Effects) position, you get a gain and mix control. Use them to blend GR-55 and normal guitar input if you still have a non-gk guitar you want to use....or decide to make the mod below.

Tomorrow, I am installing a REAL, UNBUFFERED GUITAR OUT jack in my GR55. I will pick off the signal from the 13-pin jack's terminating board. This will give me a noise free guitar out just like my VG-99 has. Then I'll have tons of options via KPA front jack and Stereo Loop.

Next is MIDI setup so KPA rigs are changed via GR55 with correct pre or post Stereo Loop settings depending on what tones I want, ie: KPA with straight guitar, synth sounds, GR55 alt tuning, GR55 acoustic, modeled guitar, etc....I am super excited this is gonna work.

bd

You can monitor the KPA with headphones. Remember that the profile comparison is between the mic'd amp and the KPA...not the "amp in room" sound vs KPA. The KPA doesn't capture all of the room dynamics since the mic is placed close to the speaker. The videos that inspired many of us to buy the KPA have audio that is most likely a direct feed from the mic'd amp and direct from the KPA. So, if you could mic your amp up to the KPA then, in a different room use headphones to compare both, that would be your best test.

bd

FRFR is a term definitely coined or at least adopted by guitarist. It came about because most guitarist don't understand why amp modeling devices sound horrible through their guitar amps. They want the modeller device to make their amp sound like a different amp....which it cant do because the amp has a fixed voice, or tonal color. The more technical guitarist recognized this and sought out un-colored, neutral sounding amplification. Keyboard amps, Bass amps, PA Cabinets, floor wedges...anything EXCEPT a guitar amp. They called these speakers Full Range Flat Response = FRFR and although no speaker is perfect, by design these speakers attempt to faithfully reproduce the signal without drastically changing the tone.

Take your favorite song recording and play it back through a guitar amp. It will sound very different, probably really bad. Well thats what happens when a modelled (ok...profiled) Kemper output is sent to a guitar amp. The fidelity is destroyed. Using the KPA as a peamp only helps but now you lose versitility since your guitar amp will always have the final say in your tone.

An FRFR system should be as transparent as possible so our KPA profiles sound as intended.

Kemper pulled the ultimate bait and switch whem marketing the KPA. They showed videos and called it an "Amp" and never clearly explained how it amplifies. BRILLIANT! However, the downside for the "real amp" user is discovering its best to use FRFR gear to realize the full potential. The cool thing is that amp users can gradually migrate....or just use the KPA as a preamp

I'm a FRFR player. I use a 500w stereo keyboard combo amp (Motion Sound KP500sn) as my stage monitor that is reasonably FRFR and I feed the main mix directly....nothing mic'd.

bd

After several hours of trying to get the heavy hiss to go away...I give up. The Roland GR55 has cheap circuitry. The signal to noise on the guitar out is so great, its unusable with amp profiles that have any gain. What a pity. Why even include the guitar out jack with such a crappy lo-fi signal?

The GR55 / Kemper combo would have been perfect....

How about using a usb thumb drive just for the track files? Its solid state....the hard disk isn't accessed in real time that way. Its a cheap workaround.

bd

sheguitarplayer,

Musicman65 from VGuitarForums here.

I've been out of town for a week so no more testing. I am back and will get back on my GR55 / KPA testing, One thing I did notice was a very small loss of fidelity on the magnetic pups going through the GR55. This could be due to several things including a buffer circuit in the GK interface to send it via 13-pin. I'm thinking its a slight high end roll-off and an eq tweak can easily compensate. Humbucker users may never notice. The modelled guitar tones sound great. Alt tunings and polyphonic effects like the poly whammy pedal are sooo cool with the KPA's surreal tubey-ness.....very nice.

I will pay more attention to noise levels and other issues and report back. MIDI program change to get the KPA to follow theGR55 and also how to mix KPA and GR55 stereo signals are next. A mini 4 channel mixer will be required.

bd

I would like a rack version with the following:

1. a full MIDI interface for external control and outboard gear
2. separate xlr and trs stereo outs with full parametric 4 band eq on each (to allow balancing stereo FRFR on stage and stereo FOH main feeds)
3. an internal energy storage capacitor to allow a 5 second power loss ride through (would eliminate a reboot on a short brown out/power blip)
4. a software editor for easier config since the rack will have reduced or more condensed front controls.

bd

I posted this in the thread requesting a keyboard interface for naming profiles then realized it should be in this thread too...

------------------------------------------------------------------------------------------------------------------------

I notice there's a network port on the back....so here's the most
innovative and universally versatile way I've seen a device
configuration utility implemented.

Create an embedded webserver with DHCP (so clients have zero config to
connect) that pushes a web-based editor to any browser based client.
That would allow PC, Mac, iPhone, iPad, Android, Linux...and any other
web client to connect and access the KPA. I sell an idustrial device
that does has that and it is cool. No software to install, updates come
with the firmware. Its way cool. You would be shocked at how robust and
interactive a web-client can be....sliders, dials, charts, buttons, etc.

Be the first and embed your software utilities IN the device. This is
nothing new for network peripherals like wireless access points, etc.

bd

I notice there's a network port on the back....so here's the most innovative and universally versatile way I've seen a device configuration utility implemented.

Create an embedded webserver with DHCP (so clients have zero config to connect) that pushes a web-based editor to any browser based client. That would allow PC, Mac, iPhone, iPad, Android, Linux...and any other web client to connect and access the KPA. I sell an idustrial device that does has that and it is cool. No software to install, updates come with the firmware. Its way cool. You would be shocked at how robust and interactive a web-client can be....sliders, dials, charts, buttons, etc.

Be the first and embed your software utilities IN the device. This is nothing new for network peripherals like wireless access points, etc.

bd

Bob,

great idea! The MIDI Thru port on the KPA could transmit commands to an FX rack from a MIDI floorboard controller. An added advantage would be the ability to control FX independently (like tap tempo) without changing rigs.

I am really hoping for a full MIDI implementation at some point.

bd

Quote from Zappledan

+1 Great idea

XML is an AWESOME idea. That would open it up to user developed tools. A full MIDI implementation would also allow easier development of an editor. Look at the user-developed editor by "Gumtown" for the Roland GR55. This was done courtesy of Roland's thorough and robust MIDI interface, despite the fact Roland won't provide an editor.

I see the Kemper engineering team as being much more responsive and dynamic so, with the right choices, the sky's the limit!

bd

The ideal footpedal / floorboard does not exist so why bother trying to create it? Short answer: convenience.

Long answer:

Every player has his own needs and other equioment to interface to. A dedicated floorboard is nice for newbies and minimalist but the majority of adopters interested in modeling / profiling type gear are already using (or will discover that they want) interfaces to other outboard gear. MIDI makes it possible for a single floorbard of your choice to control your rig and any parameters available in your gear.

So yes, I'd appreciate a descent proprietary floorboard....BUT....I'd REALLY APPRECIATE a full MIDI implementation. I have an existing rig and would like to integrate the KPA into it. If more features where remotely accessible with MIDI, that would be great. Ideally, ALL parameters would be exposed. This would allow users to create computer software such as backup/restore utilities, profile editors, floorboards, iPad/tablet interfaces....the possibilities are limitless. Look at what users have done with the Roland GR55 which has a robust MIDI interface!

I consider the KPA to be pro gear....and MIDI is what the pros know.

bd