Acoustic guitar amplification concepts

[conecaster]

In the genre of amplified acoustic guitar sound there have been few conceptually unique devices that capture the guitar's sound.

Most, but not all of these devices, capture the guitar's total sum of frequencies entirely. In other words all of the sound is summed into 1 signal at the source.

There are a few exceptions. In some cases more than one source is combine to create a single signal. In some cases there may be some phasing between devices to limit cross over between them.

A signal containing all energy from the strings and or body resonance is a summed signal.

This means there is no way to control the signal without notching and or high and low pass filtering at vol.s higher than the guitar naturally produces.

Here is a list of the common concepts deployed.

1) microphones

2) sound board sensors

3) under saddle transducers


Microphones can be frequency limited, but other wise capture the full range of Hz and combined into a single source that is sent to an amplifier. Internally placed microphones are dealing with body cavity compression which makes using them more challenging.

Sound board sensors are usually very simple peizo elements, but some sensors are more involved. The ES1 Taylor sensors were made using a coil design which was different.

Under saddle pickups were often made with individual elements all summed into one signal. Later materials were deployed that are one long transducer which sums all strings on one single element.

In recording technology the ability to record instruments on separate tracks revolutionized the industry.

Over 30 years ago the concept of string isolation was deployed for guitars by RMC. This design features individual pickup saddles for each string. The saddles used physics to create one way filters mechanically. So the string energy goes into the pickup but the top energy does not transmit back into the string. This concept breaks the cycle of energy at higher amplitude.

But imagine having the ability to send a separate signal from each string to a sound engineer to mix the sound of your guitar one string at a time. For lack of better description that is what GoAA does before the signals are summed and sent off the guitar.

This changes the capability to control a guitar's amplified sound in a host of ways that a summed signal can not provide.

There are many who seek advice here about various products. In most cases the concepts being deployed fall in these 3 categories.

Let's compare more recent products to the past.

Current top mounted sensors are usually peizo elements. These devices are, in concept, the same as the Barcus Berry sensors used 50 years ago. Barcis pickups were mounted in soft adhesive. The diffetence in rid e is the capacitance of the elements.

Microphones were abandoned years ago due to many feedback problems. Today internal microphones are made to resist Hz that interfere in the signal so this has improved over the past. But a mike is a mike.

Undersaddles or saddle pickups containing elements were originally introduced to help contain cycling and prevent feed back at high vol. In the case of under saddle pickups compression is limiting amplitude in that pursuit. This causes tonal issues many reject.
The later under saddles have the same mechanical issues.

Having made guitars for high vol applications for a 1/4 century, concepts like the 3 above are inadequate to provide Acoustic amplification for featured Instrumental guitatists. RMC was effective especially for nylon string guitars. It was the only system
I could offer to a guitarist who had to compete with bass and drums and Sax, etc.....

But after 12 years, of pursuing amplification that over comes the summed signal issues, that leave a guitar exposed to a host of issues, we have developed a multi signal system that interacts between strings and a 6 input preamp, designed to overcome amplification issues and make the live experience about the player and not a compromise every time the guitar is plugged in.


Our experience is now deployed by many great and even legendary guitarists.

Here is one you have probably never heard of before.

But, you have heard him





I think 50 years of the same old concepts is reflected in the words presented here, by someone who has tried it all, done it all and now can do more than he could before.

[Sev112]

Very interesting

Ps what happened to magnetic pickups for acoustic guitars ?
And I see and read that microphones in from of a soundhole are the best, but you suggest they were decided to be poor years ago - have i misunderstood that ?

[Robin, Wales]

Yep, you are missing sound hole mag p/us that have had, and still play, a very important role in the amplification of steel string acoustic guitars.

Microphones were abandoned years ago due to many feedback problems...

I would say that's quite a stretch of the truth. Ear Trumpet Labs mic's are becoming very popular with acoustic guitar folk artists for live performance. And artists such as Welch and Rawlings have always gigged using mic's. I recently saw Jonathan Byrd play a 7000 seater using just a dynamic mic' for his D-18. If anything, modern sound desks and pa systems make using a stage mic for acoustic guitar a more viable option than in years gone by.

The sound hole mag p/u plus a stage mic blended in was the favoured acoustic guitar amplification of John Prine.

So, personally, I would say that your premise is on shaky ground. But that takes nothing away from the usefulness or performance of your p/u system, just your argument.

PS The photo in your post is not displaying.

[Robin, Wales]

Double post

[Chipotle]

As always, the truth is... "it depends".

For a small, quiet(ish) space, with a solo or small acoustic act, mics can work fine. You'll get the most "true to the guitar" sound. And as Robin points out, modern PAs with surgical parametric EQ and proper speaker & mics selection and placement can also help.

But loud environments, or trying to integrate an acoustic with a full electric band, is a horse of a different color. Mics may well feed back, and tbh to get an acoustic to be heard, you *don't* want "my guitar but louder". You need a different tone to cut through the mix. Various types of pickups and processing systems can help in this situation.

Then there's the in-between, where you do want the "true guitar" sound but don't want to mess with the potential difficulties of a mic, especially in unknown or problematic spaces. Still other pickups and processing may be preferrable here.

Nothing out there is one size fits all.

[conecaster]

Originally Posted by Sev112

Very interesting

Ps what happened to magnetic pickups for acoustic guitars ?
And I see and read that microphones in from of a soundhole are the best, but you suggest they were decided to be poor years ago - have i misunderstood that ?

I think of an electromagnetic pickup as a cross over from the solidbody guitar. I guess in my mind its a gray area.

But thanks for pointing it out.

[conecaster]

Originally Posted by Chipotle

As always, the truth is... "it depends".

For a small, quiet(ish) space, with a solo or small acoustic act, mics can work fine. You'll get the most "true to the guitar" sound. And as Robin points out, modern PAs with surgical parametric EQ and proper speaker & mics selection and placement can also help.

But loud environments, or trying to integrate an acoustic with a full electric band, is a horse of a different color. Mics may well feed back, and tbh to get an acoustic to be heard, you *don't* want "my guitar but louder". You need a different tone to cut through the mix. Various types of pickups and processing systems can help in this situation.

Then there's the in-between, where you do want the "true guitar" sound but don't want to mess with the potential difficulties of a mic, especially in unknown or problematic spaces. Still other pickups and processing may be preferrable here.

Nothing out there is one size fits all.

Thank you for articulating my point Jeff.

I was referring to the issues of internal mikes, compression and EQ issues that make placing one in a guitar very difficult.

Many times a miked studio sound will have rumble. Many of the guitarist I have worked with are recording direct and adding room ambient mike in the mix.

But here is a recording with no mikes, direct to the board set flat with some eq.

I do not think competing with piano is going to work well with a mike.

https://drive.google.com/file/d/18qz...w?usp=drivesdk

The project this came from was #1 on billboard for 18 months.


By contrast

This recording is the pickup system combined with mike




Lastly here is the highest vol application, live through a massive PA with drums and sax blaring directly at the fully acoustic guitar.



I know, it starts out of focus, hang in a bit, it clears.

I know the sound guys on this video. They do nothing but set the guitar flat. They are not notching anything

The #1 goal for us was to Eliminate feedback. But, as a low vol sound, it has many advantages.

So how do the 3 concepts of old systems do in any of these applications.

When I set out to find answers I was not chasing after an undersaddle or top transducer, mikes were out of the question.

To make something that fit the need we had to go further into a direction that had a lot more to offer.

The answer is, independent string isolation in the signal. The strings must be independently EQd before summing. There is a lot more to it but it starts with this concepts which does not exist in the products so often discussed here in this forum.

A hollow es335 is known to feedback even with electromagnetic pickups.

A sound hole pickup is still a summed signal, not capable of string isolation.

If we keep deploying the same concepts we will get the same results.

I refrain from commenting on discussion about what people experience and say, but I feel a bit more qualified to say that none of the standard options add any value to my instruments. They are inadequate for my needs.

So I started this duscussion to generalize the concepts rather than get into debates over how many angels can dance on the head of a pin.

Your feedback is much appreciated. Even if most was to jump on the electromagnetic pickups That I just don't find to be a true acoustic amplification device. IMHO.

[Rudy4]

Originally Posted by conecaster

Thank you for articulating my point Jeff.

I was referring to the issues of internal mikes, compression and EQ issues that make placing one in a guitar very difficult.

Many times a miked studio sound will have rumble. Many of the guitarist I have worked with are recording direct and adding room ambient mike in the mix.

But here is a recording with no mikes, direct to the board set flat with some eq.

I do not think competing with piano is going to work well with a mike.

https://drive.google.com/file/d/18qz...w?usp=drivesdk

The project this came from was #1 on billboard for 18 months.


By contrast

This recording is the pickup system combined with mike




Lastly here is the highest vol application, live through a massive PA with drums and sax blaring directly at the fully acoustic guitar.



I know, it starts out of focus, hang in a bit, it clears.

I know the sound guys on this video. They do nothing but set the guitar flat. They are not notching anything

The #1 goal for us was to Eliminate feedback. But, as a low vol sound, it has many advantages.

So how do the 3 concepts of old systems do in any of these applications.

When I set out to find answers I was not chasing after an undersaddle or top transducer, mikes were out of the question.

To make something that fit the need we had to go further into a direction that had a lot more to offer.

The answer is, independent string isolation in the signal. The strings must be independently EQd before summing. There is a lot more to it but it starts with this concepts which does not exist in the products so often discussed here in this forum.

A hollow es335 is known to feedback even with electromagnetic pickups.

A sound hole pickup is still a summed signal, not capable of string isolation.

If we keep deploying the same concepts we will get the same results.

I refrain from commenting on discussion about what people experience and say, but I feel a bit more qualified to say that none of the standard options add any value to my instruments. They are inadequate for my needs.

So I started this duscussion to generalize the concepts rather than get into debates over how many angels can dance on the head of a pin.

Your feedback is much appreciated. Even if most was to jump on the electromagnetic pickups That I just don't find to be a true acoustic amplification device. IMHO.

Just don't try and convince Richard Thompson that all those years of touring his Lowden with a Sunrise was a error in judgement.

[conecaster]

Originally Posted by Rudy4

Just don't try and convince Richard Thompson that all those years of touring his Lowden with a Sunrise was a error in judgement.

I have direct knowledge of Thompson's use of devices.
He tours with an engineer who choreographs the balance between mike and pickup.

So in one piece the engineer is shifting between the two as part of the presentation.

Richard has never used GoAA.

I believe we could help him.

But using this as an example of comparative amplification is a bit outside of the issues presented unless we look at this kind of engineering as the glaring deficiency of concepts that have to be so manipulated to achieve what an artist wants.

I encourage people to use what they use, this thread is to explain how they work and why they do not work so well. Are players truly happy with the plugged in sound they get? That has not been my experience.

These very inadequate devices (my opinion) will not go in one of my guitars and the points I am making, about the concepts repeated in just about every prouduct offered, are not in question.

People tolerate amplified acoustic sound.

We want people to exploit amplification.

How about sounding better plugged in than unplugged.

How about making your access to dynamics easier plugged in.

These things will not happen if the same concepts are recycled.

GoAA had the luxury of starting out with many known guitarists in our camp, largely because through out my career I have developed so many contacts who know my standards.

The list of players I presented in the thread are all major artists. It was not GoAA buying support. Steve Oliver is such a brilliant musician, Metheny showed up out of no where but I made guitars for Klugh and they have been linked for decades and I am sure that had something to do with it.

Peter is a long time client who has played my guitars for 25 years.

I would love to add Richard Thompson. Maybe someday that will happen. Everything in its time.

With our limited numbers, against mass acceptance of these concepts, it has to be experienced first to be fully appreciated as different.

But expectations do change and that will serve all who want to better exploit live sound.

[PineMarten]

The Metheny recording is a good sound that was clearly an informed and conscious choice for the music he's making, but it *does* sound like a pickup to me. There's an evenness and solidity to the bass frequencies that is different to what a guitar (even a large bodied baritone) projects acoustically. I can see the musical usefulness of that, but it feels like a different approach than trying to capture or replicate what the instrument does unamplified.

[jseth]

Seems like you covered the bases pretty well in your original post. I've heard Metheny's clip and it sounds very good - yes, it has some of a "pickup" quality, but it's very musical.

The crux of the acoustic guitar amplification method, to me (as a lifelong working musician/guitarist) is to find a product that provides good sound at a reasonable cost. I mean, let's face it - in over 50 years of performing, the vast preponderance of the gigs I've played have been in places that paid less than $150 for the night. Having a system that costs nearly $1,000 per guitar just isn't remotely feasible for me, and it never has been.

In this case, we're talking about something usable that sounds good that is at least marginally cost-effective. I didn't get into this to have all the costs balance out, but I'm not willing to be entirely stupid the cost of my gear!

[conecaster]

Originally Posted by jseth

Seems like you covered the bases pretty well in your original post. I've heard Metheny's clip and it sounds very good - yes, it has some of a "pickup" quality, but it's very musical.

The crux of the acoustic guitar amplification method, to me (as a lifelong working musician/guitarist) is to find a product that provides good sound at a reasonable cost. I mean, let's face it - in over 50 years of performing, the vast preponderance of the gigs I've played have been in places that paid less than $150 for the night. Having a system that costs nearly $1,000 per guitar just isn't remotely feasible for me, and it never has been.

In this case, we're talking about something usable that sounds good that is at least marginally cost-effective. I didn't get into this to have all the costs balance out, but I'm not willing to be entirely stupid the cost of my gear!

I understand your economics.

But GoAA does not cost $1000

In my shop I charge $450 for an installed system, that is our simple system with vol. On the sound hole.

The ES system is $475 installed in my shop.

If someone wants midi, a custom installation, that can cost more. But I have not charged anyone $1000 even for that.

I am not sure how this perception would get started.

[conecaster]

Originally Posted by PineMarten

The Metheny recording is a good sound that was clearly an informed and conscious choice for the music he's making, but it *does* sound like a pickup to me. There's an evenness and solidity to the bass frequencies that is different to what a guitar (even a large bodied baritone) projects acoustically. I can see the musical usefulness of that, but it feels like a different approach than trying to capture or replicate what the instrument does unamplified.

Perceptions, I have learned not to trust mine. In the years I have been dealing with compensation in our system I can reflect on how many times I thought I heard something but learned my perception was wrong.

Having installed the system in that guitar I can attest to its tonality. It was a bigger sound through my little Fishman mini. The bass sounded very pronounced with a bit of growl. My perception is that was mixed out to some degree. I get the impression I am hearing mike in the lows and not as much pickup. But pickup is still there.

I hear our system in the presence of the middle strings mostly. The 3rd and 4th strings are tuned an octave high.
Its a very odd tuning, I cannot even remember it right now.

Ben re engineered the inputs for the ranges of Hz of the strings, so its well compensated.

But there is no under saddle tonality if that is what you are perceiving in the bass.

We design the elements so they are not compressed and move more in the pattern of the strings. Our design features a bi-directional approach to capturing string energy. Getting tone is about the free movement of the elements. Compression causes the common dis like of Peizo tonality.

Another factor is the top design, it is a nylon string baritone, but the top is X braced as a steel string would be.

Because of how the preamp is designed the bass response is not rolled off with a lot of high pass filtration.

If you listen to this video below you can hear how little of the bass is suppressed and how much the tonality is reflective of the guitar. Many of our clients tell us they prefer to play plugged in. They don't need to play very loud to get the added value of the clarity and dynamics which helps bring their playing out without as much effort.

I hear that dynamic in Pat's recording. I feel he is separating ranges more easily.

Many times people focus just on if the sound is reflective of their instrument. We feel transparency is captured very well in our system. But its just as much about the interaction of the player to the experience, as a guitarist.

https://drive.google.com/file/d/13As...w?usp=drivesdk

This is a very good example of player interaction.

He plays hard and the sound keeps coming. GoAA has little distortion. I would estimate -85% total distortion

If we compare that to Baggs and Fishman they range between -35 to -45% total distortion.

Head room is not necessarily required if the input of the player is lesser.

Love to hear your impression

The amp on this video is a Fender acoustic 100, their later model with the finished wood construction.

[Cuki79]

Hi

You forgot to mention the Schertler magnetico that has 6 independent electromagnetic sensors with individual electronics….

Also what about IR pedals like Tonedexter, Baggs VPDI or Fishman Aura…

Nowadays pickups can have lots of signal processing… it is not only about the sensor.

[conecaster]

Originally Posted by Cuki79

Hi

You forgot to mention the Schertler magnetico that has 6 independent electromagnetic sensors with individual electronics….

Also what about IR pedals like Tonedexter, Baggs VPDI or Fishman Aura…

Nowadays pickups can have lots of signal processing… it is not only about the sensor.

Interesting about Schertler pickup. We will have to see how we can exploit that in our system. Its News to me.

As for all the IR

So long as the interaction is a summed signal from the bridge I see no improvement in Feedback suppression and or touch sensitivity.

I think what we must accept is that source signals are the analog generator of all digital devices.

What we are designing is a stand alone signal output that does not need external manipulation. Either analog or digital.

So therefore my intent here is to discuss the pickups that are used to send an acoustic signal from a guitar.