Posts by MKB

    Indeed the WL-20 is not as good a unit as the more expensive ones such as the Shure. I'm using the WL-20 in place of a Line 6 G50. But I like the WL-20 as it sounds good and works as well as I need it to, it has rechargeable batteries, it's a much smaller solution, and I don't have to fool with the setup of the G50 RX every week.


    One thing to watch on the WL-20 RX, the blue LED. If it blinks while you're playing, it's indicating dropouts, and the units need to be paired again. I see this from time to time, but the dropouts aren't usually bad enough to cause any issues. The Line 6 G50 has had zero dropouts. I'd probably use the G50 if I could leave the unit set up all the time.

    I think this will be OK, but unfortunately SD is rather poor with their specs (not listed on the web site or in the Quick Start guide). The Sweetwater page and SD home page says 700W per channel, but then later in the Sweetwater description it says 700W total power at 4 ohms. So which is it?? I'd suggest contacting Seymour Duncan and asking directly. Or if anyone knows what amp module is used in it, and its part number, we can figure it out from there.


    If it is 700W per channel at 4 ohms, and you have a Kab in each channel, that will be quite a loud setup. But be careful as I'd expect the amp could eat the Kones alive... even at 350W it could do this. FWIW, many rack power amps with internal DSP allow a maximum output power to be set so your speakers don't get fried in the heat of battle, but I don't believe the PS700 has this feature.

    @ Frodebro

    Just a note on efficiency ratings - 2 identical speakers/cabs sharing the same power as one alone will still be 3 dB louder. If one driver has an efficiency rating of (say) 100 dB at 1 watt, two will be 103 dB @ 1 watt.

    This is indeed true, but due to a characteristic in the design of most solid state amps, you will not get the same power in each speaker if they are connected in series (actually this is the case of most amps). You can get the efficiency benefit with many solid state amps if you connect the speakers in parallel, provided the amp can handle the halved impedance.


    The 4 ohm impedance of the Kone and Kab is terrific if you use only one speaker per solid state amp output, and also works well if you have 4 of them wired in series-paralleled pairs (giving 4 ohms total). But using two together in one amp output will either require a 2 ohm impedance from the speaker (not as common as 4 ohm minimum), or wiring them in series for 8 ohms total (halving the total power from the amp).


    The main reason solid state amps act like this is due to their having a constant maximum voltage in the power supply. If you know the power a solid state amp can provide at a specific impedance, and grab a calculator and simple power equations, you can get an approximate idea of what power your speaker configuration will receive from an amp (and why your 250W amp works great with a Kone, but can't even keep up with a drummer when used with your stock 16 ohm Marshall cab).

    Thanks for sharing. Couple of Q's:

    So what are the implications of the data for enclosures etc? How was it mic'ed up for the test?

    There were no mics used. The DATS system is a measurement tool\software combination that analyzes the driver in free air. The only additional item was a calibrated weight to calculate Vas.


    https://www.parts-express.com/…nent-test-system--390-807


    BTW, for giggles I did plug the measured TS parameters into a box designer program, with estimated\measured dimensions of the Kabinet. Here's the info for that paper exercise (again no mics used). Looks like 3dB lower cutoff of 86Hz, with a 1.2dB bump at 160Hz. These are approximate results, the cab dimensions are estimates (not sure what the MDF thickness is).

    Kemper Kabinet 09_28_20.pdf


    You could use this info to design a ported cab, but the parameters of the Kone seem to suggest that you might not get much low end benefit from a ported cab vs. a closed cab. You can throw the TS parameters into a cab design program and estimate the low end results of a specific design however.

    Jinjer... one of the first bands my new son in law and me bonded over (he's 24 and I'm 59). We're planning on going to see them when they come around here after COVID. If they can convert this old man to cookie monster vocals, they have some serious universal appeal. Quality and melody goes a long way in any musical genre.


    Later when nobody's looking I'll be grabbing the OS7 and Kemper, saddle up a few 5150 profiles, set the Kones to V30, and tune dooooown.... :)

    I've had a Kone for a few weeks and liked it so much I bought two more. Finally was able to use one in a old Rocktron S112 cab at a loud practice a few days ago, and was extremely pleased with it. IME the big issue with modelers and the Kemper is to get convincing tone at high stage volumes, as all kinds of nasties can pop up. None of these appeared with the Kone. The biggest issue I can't stand is harshness or piercing highs, and the Kone has none of this. The power amp I used was a ICEPower 50ASX2BTL built into my unpowered toaster (this is the same amp module used in the Duncan Powerstage 170), and it showed no signs of running out of headroom. And it gets the pop of clean notes, which is very hard for some stage modeler solutions to get right.


    The only thing I have found unusual about the Kone is the bass response. The Kone appears to have an extended low end with perhaps a low free air resonance, which can give it a sensation of lots of bass in some cases. It seems to be optimized for smaller sealed cabs (the Kab is fully sealed, no port, and is relatively small). In the S112 ported cab, I had to drop the bass in the monitor EQ quite a bit to get it to balance. I have another Kone in an old Peavey 1x12 plywood wedge cab that is barely big enough to hold the speaker, and while other speakers sound thin in the bass in it, the Kone is just right. I expect if I seal the port in the S112 it will sound much better with the Kone and flatter EQ settings.

    Wow....That is a huge bummer. I hope they are able to make a change to that....Had I been aware that it was not possible I would have likely held off buying the Kabinet until that functionality was available. I really like the Kabinet and the Imprint technology really does make this feel like an amp in the room.

    IIRC Kemper has already said they will be enabling the selection of imprints per RIg in a future firmware release. It should be on the way soon. And really, the entire Kone concept doesn't make a lot of sense unless you can select an imprint per Rig. If not, and you were forced to select one global imprint, you'd just as well buy the real speaker the imprint models and go with that (it would be less expensive than the Kone in many cases).


    In our software development at work, we have the "stupid" rule. It means that if a customer uses your product, and a feature's operation or the lack thereof makes the customer say "That's stupid!!", you need to fix that issue. The Kemper Kone operation with only a global imprint fails that rule IMHO. However, having the present operation of Kone firmware and a Kone does make a lot of sense if you are simply replacing a FRFR and are using the Kone full range for all profiles.

    A few years ago I purchased a couple of Celestion speakers, one of them had a similar noise. After looking at it closely I discovered that the dust cap was not glued on correctly, I could pull it up on one side with my finger nail. I carefully applied some glue with a toothpick, let it set overnight and it fixed the issue. Not sure if that's your issue, just a thought...

    A few years ago I bought a nearly new but used Celestion Heritage G12-65 from a seller on ebay. When it arrived it appeared to be in perfect shape, but had a horrible rubbing sound. Being an amateur speaker reconer (have reconed maybe 15 or so Celestions), I guessed it was "crap in the gap", which is debris between the coil and polepiece. The only way to tell this was to remove the dust cap, but I had a replacement that was suitable (dust caps are a huge part of the tone of a speaker BTW).


    Turned out the issue was a sliver of metal that looked like it was left over from when Celestion drilled the polepiece vent. This was probably left loose in the polepiece or motor area, and was held in place by magnetism. The shock of shipping probably knocked it loose, and the powerful magnetic field in the gap pulled it into the gap area. Simply removing the sliver with tape (standard speaker gap cleaning technique) removed the metal, and after replacing the dust cap, the speaker has sounded perfect ever since.


    The point here is that all products can have issues; they shouldn't, but unfortunately it does happen. And the issue here is most likely Celestion's fault, not Kemper's. The Kone is made in China, and the Heritage I have was made in the UK, so it doesn't matter which factory it was made in. If there is an issue with this run of Kones, I bet Kemper will crawl all over Celestion to get them right.


    If the owner does decide to look inside the speaker (not sure if that will void the warranty or not), be sure to look carefully in the area between the spider and where it attaches to the cone. That area has the entire magnetic field of the magnet focused in a tiny gap, and if there are any washers or screws loose in the cab, they could be attracted to that area and cause noises. I once bought a used "defective" vintage G12H-30 Greenback that had a terrible rattle, but the issue was only some metal shavings in that area. Pulling those out with tweezers repaired the speaker in seconds.

    What two-way speakers have you been using?

    Quite a few wedge monitors over the years. The one that did this compression thing the most was a new EV ZXA1-90; it totally fell apart in response on the first gig. As the volume on stage got loud, all that could be heard from the EV was the tweeter, everything else was inaudible above the other instruments (4 piece horn band). There were a few Carvin 12" unpowered wedge monitors that did this, along with a Mackie 12" powered one.


    Another related problem is when the power amp runs out of headroom and starts clipping, but you are using an unpowered monitor with a crossover and tweeter. The harmonics generated from the clipping are faithfully reproduced by the tweeter, and that does not make for a pleasant sound. I had this happen on my last gig with a F12-X200 and an ICEPower 50ASX2BTL power amp; it ran out of steam from too much lows and started clipping, and the tone got really harsh. For this reason, I'd like to personally thank you for the 4 ohm impedance of the Kone!! Just doubled the usable power from the ICEPower amp module.

    Ah, thanks :)
    So is the compensation always on, even in Imprint mode and when no audio is fed through Aux in?

    Let it be clear that I meant that as a compliment, to acknowledge the quality of sound I've been hearing about when Imprints are used ;)


    Also, totally agree on some 2-way speaker/cab being too bright! Too often, tho, the electric guitar player end up believing that a tweeter unavoidably makes for a harsh sound, and you'll agree this is another myth to debunk :) Of course, if we send a linear cab the signal we use for a guitar cab, we get unwanted harshness.


    Happy Easter!

    The real problem I've found with a tweeter in a FRFR used for guitar is something you don't hear mentioned very much. When a woofer\tweeter cab is designed, the crossover is engineered to allow proper integration of the drivers over the frequency range. This usually involves some attenuation of the signal to the tweeter as compared to the woofer, as the tweeter is usually more efficient. But the problem happens at loud stage volumes; often the woofer can run into acoustic compression and hit a maximum volume level, even though you put more power into it. This is a form of speaker distortion you hear often in loud amps. But since the tweeter is more efficient and often has a higher maximum acoustic output, when the woofer is at its acoustic max out, but the power is increased further, the tweeter will continue to get louder and be unbalanced with the woofer acoustically. That makes the tone very unpleasant at high volumes.


    I've been trying to get whizzer cone speakers to work in my guitar rigs for years now for the above reason, but have not been successful as that type of speaker has too many dips and peaks in the response. I was quite excited to see Kemper using whizzer cones, and they have done a masterful job taming the problems with them, while keeping the benefits (mainly lack of harshness and even response over volume range). I strongly feel that the Kemper approach is the best yet devised for giving the most versatile and full frequency response for modeler speakers at loud stage volumes.

    In general it is better to use speaker cables for speakers, and instrument cables for instruments, but only from the perspective that each cable has the design requirements of its use taken into account. I would rather use a high quality instrument cable to a speaker than a cheap speaker cable.


    There are only two ways I can think of that would cause a bad cable to kill an amp; one is if you are using a tube amp and the speaker cable loses continuity. That could happen with a speaker cable or instrument cable; often both cables will use identical connectors, and solder joints could fail in either.


    The other way would be if the amp is solid state and sensitive to capacitive loading on its output, and you are using a shielded instrument cable of sufficient length to present enough parallel capacitance to the amp to cause issues. The old Crown DC300 was notorious for going into ultrasonic oscillation and malfunctioning with high capacitance loads, but newer amps are mostly protected from such issues.


    Using an instrument cable with a Kemper and Kab shouldn't necessarily be a problem, but if the cable is long and has enough series resistance, it could dissipate significant power over its length, and that means heat. But it is highly dependent on the cable length, cable characteristics, and how loud the speaker is playing. Just because a cable has resistance (and all cables do), and power is being dissipated, does not mean it will feel hot. Every resistor ever made is turning power to heat, but most you encounter do not feel hot. It depends on the power being dissipated and how much area is present to dissipate it to the surrounding environment.

    FWIW, over the 4 years or so I've owned a unpowered Kemper, I have tried every power amp I can lay my hands on with it. I tried the Kemper and external amps with both FRFRs and standard guitar cabs and speakers. Here's a brief list of at least the ones I can remember:


    McIntosh MC30

    Dynaco ST70

    Multiple Marshall tube amps power stages (Haze 40, VIntage Modern 100W)

    Behringer NU1000DSP rack class D power amp

    Marshall 8008 Valvestate rack power amp

    Crate PowerBlock (using the RCA input with no speaker emulation)

    Multiple class D power amp modules with different chip sets (TI TPA3116 in regular and bridged mode, Tripath)

    Peavey Bandit Transtube power amp stage

    ICEPower 50ASX2BTL module (same as in SD Powerstage 170)

    Sure AA-AB31241 600W class D power amp module


    In most cases, the solid state amp modules had a similar feel in the lower mids and bass, kind of a plastic fake sensation. The tube amps seemed a bit mushy and indistinct, for the lack of a better term. Very distracting and disappointing in most cases, and I really didn't enjoy the experience due to this coloration. I was not happy with the majority of the amps, even though I was very pleased with the direct tones of the Kemper.


    But the single amp I've tried so far that was significantly better than all others (tube or solid state) in tone and feel is the ICEPower module. The distracting tone and feel in the lower mids and bass is absent with that amp, and I found I could lose the sensation I was playing a profiler and get lost in the tone. This has endured over the last year I have used the ICEPower. IMHO there really isn't any other choice. The next one I plan to try is the ICEPower 200ASC module, promises to be a bit easier to integrate than the 50ASX2BTL.


    But overall, if I had to do it all over again, I would have bought a powered Kemper. After 4 years of Kemper use, the internal power amp is essential for my needs.

    I don't have a SD 170, but have used a 50ASX2BTL module extensively with my unpowered toaster over the last year or so, and am very happy with it. It works very well, has been very reliable and trouble free at gigs, and was well priced. Also it had a better tone and feel with the Kemper than any other power amp I tried with it, tube or solid state. However it was very difficult to DIY it into the Kemper, I wouldn't want to try that again.


    I don't understand why SD used a fan in the 170; the 50ASX2BTL is designed specifically to not need one, and under volume levels at a gig that caused clipping, the 50ASX2BTL in my Kemper toaster got barely warm, and I didn't use a fan. Maybe the SD 170 enclosure is so small the heat became concentrated at high power levels, but even then you might get away with convection cooling or a very slow fan. Just a tiny bit of airflow makes a massive difference in heat dissipation.


    I'm planning on building a ICEPower 200ASC module into my next Kone cab; that module puts out [email protected] ohms, and promises to be far easier to work with than the 50ASX2BTL. The 50ASX2BTL requires a balanced input and needs a bit of gain to make it work its best with a Kemper, but the 200ASC can use a single ended input.

    If anyone is looking for an inexpensive 1X12 cab for a Kone, I haven't seen anything better than a used Rocktron S-112. I bought a pair of them last year from a local music store for $120, and they are awesome for the price. The speakers that come with them aren't very good, but the earlier cabs with cloth covering and no corner protectors are made of plywood, and are quite high quality. The later painted ones with metal corner protectors are made of MDF. My Kone sounds great in one.

    I'm wondering if the issue with Kone\imprints not working as well with high gain tones as low gain ones is the cab the Kone is installed into. The tone of a 4X12 cab has a lot of influence from the construction and wood used in the cab; that huge piece of wood on the back, only supported in one place, will definitely have a sonic effect. To my knowledge, the Kone imprint is specifically created to not have any cab coloring (unlike a standard cab IR), it is meant to sound as close to the raw speaker as possible. So to get the tone of the cab, you have to install the Kone into such a cab and set its imprint accordingly, or set the Kone full range and use an IR of the preferred cab.

    I've been trying out all combinations of Kone full range and imprints, and there seem to be some profiles that sound better with Kone in full range than with imprints (mostly heavier gain profiles or ones with lots of full range effects), but as the profiles have less overdrive, the imprints start winning out. Fender clean profiles with Kone alnico imprints are a thing of true beauty.


    I haven't heard a lot of difference with the Sweetening control, but will do more experimenting and focus on that. In the cab I'm using (an old Rocktron ported 1X12), it sounds mighty good with Sweetening and Bass Boost off, and Directivity on full.


    One thing I did notice; in a side by side comparison with a F12-X200 in an identical cab, the Kone sounds FAR better in Kone full range mode than the Celestion F12-X200. No real comparison actually; the F12 has too much high treble and a low midrange bump not present in the Kone. The Kone full range actually sounds amazing playing Steely Dan... :D