[martingitdave]

This will be a thread in multiple parts. Check back and I will update it over the next few days as time permits.

Part 1: Why use a K&K?

Many thousands of pages on AGF have been devoted to the topic of which pickup system to choose. I probably contributed to half of them. :-) In the end, my pickup choice was one of attrition, not chosen as an ideal solution. What does that mean? Well, I've tried many active, passive, dual source, and digital IR based systems. They all work - and many work well. In the end, my decision was based on finding the right guitar, with the right tone, and then putting a pickup in that wouldn't alter the tone or weigh down the instrument. I chose the K&k because it meets those needs, I'm familiar with it, and the tone is easily shaped with various outboard gear readily available today. Your mileage is almost guaranteed to vary.

Part 2: So, you have a K&K… Now what?

Now that you have taken the plunge and recently installed a K&K, you may be asking yourself “what the heck do I do now?” Well, the simple answer would be “plug one end of an instrument cable into your guitar, and another into an amplifier.” If after doing this simple act you are satisfied with what you hear, please stop reading this post, close the browser window, shut down the computer, smash it with a hammer, and forget this thread entirely.

If you're still reading then we have established the fact that your tone snobbery has led you to surf the Internet for advice on how to make the minimalist’s favorite K&K pure mini pickup, that you no doubt installed in your fine hand crafted instrument, sound just like your guitar only louder, I will quote Larry Fishman. “Simple, you can’t.” Huh? Yes, it’s true. You can’t do that. The acoustic guitar is too dynamic and expressive from both the listener’s (and more importantly) the player’s perspective that no pickup system will capture that magic.

Now, don’t despair. There are multiple reproduction techniques that are available with differing realism. It’s analogous to seeing the ceiling of the Sistine Chapel in person, versus watching a 3D video, or a photograph, to finally a hand drawn cartoon on the back of a napkin. No reproduction will offer the same experience as seeing something with your own eyes in person. The same is said for the acoustic guitar. Hearing it in a room in person is a different experience than any sound reinforcement technique.

Essentially, before you start, you must choose how deeply you want to dive down the rabbit hole. Will you be satisfied with the cartoon, the photograph, or do you want the 3D video? Secondly, you must establish the benchmark for comparing your pickup's signal path. My benchmark is the sound of a quality instrument microphone pointed at the 12th fret of the guitar about a foot or two away from the instrument played through a high quality PA system. In the analogy above, this is the 3D video. It's the best sound reproduction of an acoustic guitar available to us today.

Part 3: The Cartoon

Assuming you're not satisfied with the guitar-cable-amp solution, the first level of tone shaping available for your passive K&K pickup is the basic preamp circuit. I'm not an electrical engineer, so I will (over) simplify the following discussion. The signal coming from your pickup is a piezoelectric signal generated from the mechanical vibrations of the bridge plate through three simple transducer discs. Other than using a single disc, it's about as simple as you can get. This signal is strong but it has an awful lot going on. It's raw and may be slightly out of phase. It's unprocessed and unbuffered. It's au naturale. But, for a lot of people, it works because it conveys some of the complexity of the sound of an acoustic guitar. Let's call it what it is: "a hot mess."
:-)

Your hot mess signal is not too different from all the other hot mess signals in the world of music. Luckily, folks out there have made some simple pre-amplification solutions that will tidy up this signal as it makes its way to the big world that lies outside of your instrument cable. What these simple preamps usually offer is a clean high headroom buffered signal that is designed to match the impedance of the next input stage in your amplification chain. I consider the "cartoon" solution to be a simple preamp that has impedance matching and will help preserve the frequencies that are weaker. Sometimes these preamps will include some EQ features, which are helpful. Some examples of the equipment I've purchased and used with the K&K, that falls into the "Cartoon" category, are:

1. Red Eye
2. K&K External Preamps
3. K&K PrePhase Internal Preamp
4. MiSi Custom Preamp
5. Various 2.4 GHz wireless systems (Currently Using XVive U2 and Line 6 G10S).

The K&K external (belt pack) products are probably the easiest to use for most people and include a circuit designed for their pickup. It will also give you some basic EQ control and phase switch, which can come in handy. But, if you want something simple and easy to use in a semi-professional, or amateur situation (Church, clubs, etc.), you might want to consider the wireless solution that I am using today. As long as you have EQ capability somewhere downstream, it will take care of the most basic needs: pre-amplification and impedance matching. And, wireless has the added benefit of eliminating a cable.

Speaking of EQ, the K&K can benefit from all sorts of EQ. But, at a minimum, for the cartoon reproduction, I think you need the minimum of a three band EQ, with a sweepable mid frequency. Why? Well depending on your guitar, the K&K will pickup a lot of extra vibrations from the back and sides and chamber of the guitar. The mid frequency cut that seems to work best for me and my guitars is around 1000 Hz. I guess that is no surprise because K&K's own products have a mid frequency control around 1,000 Hz and some with 1,500 Hz. So, if you want the simple cartoon solution, a step up from guitar-cable-amp (plug and pray), then consider a preamp with simple EQ control.

Part 4: The Photograph

This analogy is wearing thin already, and I'm realizing that I've run out of steam. Moreover, as I type, I am also realizing this sounds more like a K&K commercial than any insights of my own. This is evidenced by the posts below. So, I won't spend too much more time belaboring it. But, in attempt to avoid being a quitter, let's discuss the the penultimate strategy for making the K&K sound better.

I would consider the next level of reproduction quality to be the dual source system: a K&K and a microphone. I'm not alone in this thinking because K&K sells this pickup in several different multi-source configurations with internal and external pre-amplification. In my opinion, this can be an excellent option for many different types of players. Rather than attempt to summarize what has been said before by the likes of Doug Young, I would encourage you to read his book or watch his videos. He apparently favors the external preamps and a simple and passive internal installation. I believe he is also using several other pickup systems, so I am not implying a K&K endorsement on Doug's part.

Until recently, this was the ultimate solution available to many of us. I have tried a number of dual source configurations with internal preamps. Some have provided a high quality result. Most were feedback prone at anything but moderate volume. That said, there are a number of professional artists that have tried everything on the market and swear by dual source solutions. Why? Because, alone, the K&K is somewhat flat sounding and one dimensional. It's amplifying the vibrations sensed on the brigeplate. While that's a huge component of the sound, it's not all the sound an acoustic guitar makes. The interactions inside the guitar are sometimes referred to as "air" in the sound. I take this to mean both the high frequencies, harmonics, etc. as well as the resonance from the chamber. The contact pickup won't capture this sound. But, a mic inside the guitar can do a competent job of capturing much of this sound. Mixing the signals together results in something that is a more realistic reproduction of the real thing. The downside to this solution feedback. Anything with a microphonic response is subject to feedback.

Part 5: The 3D Video

In the now (VERY) tired analogy above, I state that the microphone is the best reproduction you can get of the acoustic guitar for live performance. So, if you want the mobile benefits of a pickup system with the sound quality of a microphone placed in front of the guitar, you need to turn to some pretty complicated mathematics. What? You're not a mathematician? No worries, someone already did all the math and coded the software. You just need to have lots of money to spend on the latest toys. Specifically, I am talking about Impulse/Response modeling. There are lots of good threads on this topic by Cuki79 and James May. My experience is that the K&K is pretty close to the perfect platform for IR. It is simple, passive, and provides a good consistent signal. I have tried using Fishman Aura technology with limited success. I have used Cuki's custom IR's, which are excellent, but require that you have a Cuki. :-) Finally, I purchased a ToneDexter from James May. This device is about as good as you can get with a K&K pickup. You can get a result that is very close to the sound of a mic in front of a guitar, but the processing is designed to manage the frequencies that cause feedback. And, since you are recreating a signal that sounds like a mic in front of the guitar, it captures all the air that other analog systems without a microphone cannot.