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Old 03-16-2017, 11:01 AM
Dave Sharona Dave Sharona is offline
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Default K&K Mini More Prone to Feedback than UST?

So, I had the K&K Pure Mini installed in my e10OM and it sounds VERY good. Surprised, really, at how natural it is.

That being said, it seems to be a bit more of a struggle to prevent feedback in a live situation. Is this typical?
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Old 03-16-2017, 11:45 AM
RustyAxe RustyAxe is offline
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Quote:
Originally Posted by Dave Sharona View Post
So, I had the K&K Pure Mini installed in my e10OM and it sounds VERY good. Surprised, really, at how natural it is.

That being said, it seems to be a bit more of a struggle to prevent feedback in a live situation. Is this typical?
Yes. But you can improve things with a properly matched preamp ... cut the bass, cut the mids, leave treble neutral. Monitor/amp placement, as well as vocal mic placement all factor in, too. I keep a rubber sound hole plug in my gear bag when things get tough, but have only had to use it a few times over the years.
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Old 03-16-2017, 12:48 PM
guitaniac guitaniac is offline
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Yes. Soundboard pickups, by nature, are more responsive to top vibrations than undersaddle pickups and magnetic pickups. They are not only more responsive to the top vibrations caused by playing the strings, they are also more responsive to the top vibrations which are caused when the guitar top reacts to loud speaker sound.

When high amplification is necessary, judicious speaker placement, and EQing down the muddy frequencies, will be helpful. Sometimes a phase inversion will help as well. In a high volume setting, its often helpful to try both phase positions (normal and inverted) to observe which position will yield the most stable signal.
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Old 03-16-2017, 01:10 PM
jseth jseth is offline
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Yep... in situations with higher sound pressure levels, the ambient noise (from amp, PA, monitors, band, etc.) is going to cause the acoustic guitars body to vibrate, and that vibration will be picked up by any pickup (even a soundhole magnetic type)...

In a "least prone to feedback to most" order, I'd say least is a soundhole pickup, then UST, then soundboard transducers, then an external microphone... but don't kid yourself; even a magnetic soundhole pickup is going to feedback at high volume - one of the big advantages to a solid body electric guitar vs. a hollowbody...

With the K&K in my Goodall, it seems that having a good "match" for the impedance of the pickup aids considerably with how much tweaking is necessary to the overall tone and volume capabilities, although each portion of the signal chain is going to have it's own "wants/needs" for producing the final result.

Trying to have amplification on the "neck" side of the guitar, rather than the body, is the ideal (think of the guitar's body as a sizeable "resonant chamber") ... this can be hard to achieve on some stages, and especially difficult with a higher number of players (in a band format), but still an aspect to consider... you NEVER want the bassist's amplifier to be behind you if you play acoustic guitar! The results will NOT be pleasing...

I don't think there is a "standard" method for eq'ing a K&K, as so much depends upon the placement of the pickup, the guitar in question, the PA employed and the various constraints of the room itself... all these things combine to the solution being what your ears tell you sounds the best...

Good luck! Hope this is helpful to you...
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Last edited by jseth; 03-16-2017 at 01:17 PM.
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Old 03-16-2017, 01:44 PM
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Are you familiar with "ringing out" stage monitors using a microphone? If so, you can use that same basic approach to "ringing out" your K&K Mini-equipped guitar.
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Originally Posted by http://www.emusician.com/how-to/1334/masterclass-how-to-ring-out-stage-monitors/49827
... Stand at the microphone position on stage and speak into it. While you are doing this, have the person who is running the mixing board slowly (and I mean slowly) raise the level of your voice in that monitor, and only that monitor. (If you’re smart, wear hearing protection while you do this.) As the level of your voice gets louder, you will begin to hear ringing, indicating the onset of feedback. That’s when you stop increasing the volume of the monitor. At this point your job is to identify the frequency that’s starting to ring. Experienced monitor engineers can do this with frightening accuracy, but if you are inexperienced, you’ll have to guess, or use a spectrum analyzer. If you don’t own a spectrum analyzer, you can download any one of a number of available apps, and if you decide to get really ambitious, you can buy a measurement mic that can be attached to your phone for this specific purpose. PreSonus and other companies are adding spectrum analysis to their digital mixing consoles to help you with the process.

Let’s say that you’re really good (or really lucky) and you identify the frequency correctly on the first try. The next step is to have the person “driving” the system slowly (again, I mean really slowly) raise the level of the corresponding slider on the graphic EQ. If you picked the right frequency, you’ll hear the ringing get worse. (If it does not, put that EQ control back to “0” and try one of the adjacent EQ sliders. It’s a process of trial and error for the first few hundred times.) When you’ve found the frequency, use the EQ control to cut that frequency a few dB. Listen for the ringing to be reduced or eliminated. Then bring up the overall volume of the monitor a bit and listen for the ringing to return. It may return at a different frequency. Repeat the process. As you do, the ringing frequencies will likely change. Try to determine the offending frequency, raise the EQ control to confirm your suspicions, and use that same EQ slider to cut the ringing. Try not to hack away large chunks of EQ with severe cuts because then the monitors won’t sound very good. With a bit of practice, you can get the overall volume of the monitors pretty loud without feedback. Then turn them down. We don’t want to encourage excessive stage volume. Just because you can make the monitors loud doesn’t mean you should make them loud.

Keep in mind that ringing out monitors is as much a daily chore in venues where the equipment is the same every day as it is when you are on tour. Changes in temperature, humidity, stupidity, and stage setup will affect monitor EQ. Stage clothing— particularly hats—changes the way monitors and microphones react. Just because you do it once doesn’t mean you never have to do it again. But you’ll get better at it, I promise.
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Old 03-19-2017, 01:51 AM
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I have had the K&K in my HD-35 for some time now, but faced a constant struggle with feedback at every venue, which I attacked with all the usual suspects - eq, parametric eq, sound hole plug, etc. I finally stopped using it on gigs which was a shame because this is my favorite guitar to play.

Finally I'd had enough and pulled the K&K, installing instead a Baggs M80. I wish I had done this sooner. I now have a full tone devoid of mud and low mid howl, with a clarity I have long missed. The much reviled electriciness in the treble strings is easily dealt with via eq to the point of being a non issue.

The K&K does indeed, in my opinion, deliver the holy grail of "my guitar only louder." While this might be what we'd all want, I've learned it is not always what we need. And I've got my favorite guitar back.
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Old 03-22-2017, 06:19 PM
mjsb1 mjsb1 is offline
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I'll second that, I've a fishman rare earth blend, and due to constant battles balancing a Nord keyboard on stage.. I get feedback, even with the internal mic rolled completely off. Monitor position, my position on stage, position of the FOH PA + sub (in smaller venues especially) all contribute to my tops vibrations... Hence, the search for a new pickup begins, (or equally a very good Pre!)
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Old 03-23-2017, 05:35 AM
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Quote:
Originally Posted by Dave Sharona View Post
So, I had the K&K Pure Mini installed in my e10OM and it sounds VERY good. Surprised, really, at how natural it is.

That being said, it seems to be a bit more of a struggle to prevent feedback in a live situation. Is this typical?
Hi Dave

The answer is in some situations, with certain systems and techs, yes it will be more feedback prone with what I call traditional stages. If you are on a medium loud to loud stage with monitors/wedges in front of every singer/player you need to make some adjustments to manage feedback. Switching from an undersaddle pickup to a sound board transducer is a major change, and requires different stage strategy. Add an internal mic and it complicates it even more.

I have played K&K dual source (pickup plus internal mic) for about 12 years now and most of the time manage it just fine even on aggressive stages with my stage amp running waist high /bridge behind me.

I do think feedback management is a constant process, and the K&K is more prone to feedback when you are standing on top of a 12" or 15" three way monitor wedge/cabinet which is less than 30 inches from the saddle of your guitar. That's the equivalent of pointing a hot microphone into your monitor.

I always ask the sound techs take my guitar out of the monitor in front of me and often carry an UltraSound amp as my stage monitor which sits 4-6 feet behind me on a stand which puts it at waist level and it's aimed at the back of my head.

If they don't have a sophisticated enough system to remove it from just my monitor, I'll have them move the monitor to my left side about 5 feet away and prop it/aim it at my head (not my guitar). If they cannot do that, I just ask them to remove the monitor all together.

The level of adjustment of the PA system/stage monitor system coupled with the experience of the sound techs, and the quality of their equipment is paramount.

So is the sound tech's philosophy of how an acoustic is supposed to sound through a PA. If they try pumping the bass to supernatural levels when there are subwoofers in the room, be sure to carry a feed-back suppressor (big black rubber plug for the soundhole). This will almost always control feedback.

When I use in-ear monitors it's not an issue at all.



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Old 03-23-2017, 09:24 AM
guitaniac guitaniac is offline
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Quote:
Originally Posted by mjsb1 View Post
I'll second that, I've a fishman rare earth blend, and due to constant battles balancing a Nord keyboard on stage.. I get feedback, even with the internal mic rolled completely off. Monitor position, my position on stage, position of the FOH PA + sub (in smaller venues especially) all contribute to my tops vibrations... Hence, the search for a new pickup begins, (or equally a very good Pre!)
Electronic keyboards can be amplified to ridiculous levels. What you need, I fear, is a keyboard player who'll cooperate in playing at a level which is compatible with your instrument's amplification capabilities.

The only pickup upgrades (for the instrument you have) which might possibly help you are a mag pickup/soundhole cover combo, or the Barbera Soloist pickup or the LR Baggs LB6 pickup, used in conjunction with a soundhole cover. (Those pickups reportedly have some of the piezo crystals wired out of phase in order to inhibit feedback.)

As far as preamps go, the Zoom A3 can offer a great deal of precise EQ control. In addition to a six band graphic EQ and a two band parametric EQ (which can be used in series), the A3 also has a manual bass-mid-treble three knob EQ which can be used for quick and dirty tone adjustments at the gig. You also have the option of inverting the phase of your signal (when needed) if you run your pickup through the mic channel. (Its called the "mic channel", but it has a compound jack which can also accommodate the instrument cable from a pickup.)


Regarding the issue of easy ways to make the K&K Pure Mini less feedback prone, using the Pure Mini with the new ToneDexter digital processor might be an easy fix. James May, the co-creator of ToneDexter claims that it has some "secret sauce" circuitry which helps to inhibit feedback. Since Mr. May is a Pure Mini user himself, I tend to believe his assertion that the Pure Mini/ToneDexter combination isn't feedback prone in most performance situations. He's doubtless done plenty of field testing of the Pure Mini/ToneDexter combination. Beyond that, we should be getting buyer/user feedback on ToneDexter within a few months.
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Old 03-24-2017, 11:17 AM
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James May James May is offline
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Much of what has been posted in this thread agrees with my observations. K&K pickups are great, in part because they are mounted on the bridge plate, and they get to hear more of the top plate vibrations than UST pickups. But that's also why they are more prone to feedback than UST pickups.

What you can to to help, (assuming you are not using a ToneDexter):
1. adjust the load impedance your pickup sees down until you get the most natural balance from low end to high end with your installation. 5meg to 10meg typical input impedances of guitar preamps will allow all of the low end to get through and often times that's too much as it makes the balance bass heavy. You could fix this with EQ, but another approach is to experiment with a 1Meg to 100K resistor across your pickup's output and that can eliminate having to EQ the bass to be lighter. Once you find the best value, it can be installed at the preamp input, or the in your guitar's output jack, or most easily in a guitar cable plug.
2. Try both polarity choices with a phase flip switch. Every situation will be different and one will be better than the other. Of course, if you move around, all bets are off.
3. Find the main resonant mode of your guitar. For most it's the low G# but will likely be in the G to A range. Just play all the low notes evenly and listen to which one sticks out. That will be the one that feeds back first. That is the one you want to DIP with EQ. You can use a narrow notch filter if you have one available. The note most likely to feedback next is the octave above that one.

As soon as ToneDexters start shipping next month, it will be easier to get louder with KK pickups. Our intelligent feedback suppression works in the digital realm. When you train your instrument, the software reduces the amplified strength of the low frequency modes.
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  #11  
Old 04-01-2017, 08:03 AM
sublro sublro is offline
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ive owned kk pickups for a long time and struggled sometimes with feedback, to the point of going to a mag pickup imstead, finally found the solution for me is the headway edb1. ive written extensively on why, but to boil it down, the biggest problems with the k&k come from bass frequencies getting out of control. the edb1 has a high pass filter that allows you to completely kill all bass below a selectable frequency point depending on what works in a given situation. this can be much more effective when you are facing feedback than a notch filter, and what i realized in using it is that good realistic acoustic tone doesnt include as much bass as one would expect especially in a band situation where there may already be a bass, and where louder volume levels bring on feedback problems. cutting out low bass cleans up a lot of what will cause problems, at their source.
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