What You Need To Know About Flatwound Strings

Once again, Jazz Guitar Today reaches out to Brian Vance, VP of Fretting Strings and Accessories for D’Addario & Co., this time to discuss Flatwound strings.

By Brian Vance

Welcome back to our series of articles on guitar strings. The last two articles focused primarily on the history, construction, materials and applications of both electric and acoustic roundwound strings. Given there is such a direct and important association between flatwounds and jazz music, in this session, we’re going to take a deep dive into flatwound guitar strings. And, as has been demonstrated by many great guitarists, flatwounds aren’t just for jazz, so let’s dig in and understand all of this.

As usual, a little history… I will not profess to be an expert on the exact origins of flatwound strings, there is varying history out there, but they were used for violin (and other orchestral instruments) long before the modern guitar was invented. As a result, flatwound guitar string design was essentially adopted from orchestral strings, most importantly, the bass fiddle (double-bass), which was the inspiration for the first development of flatwound electric bass strings. The key difference with most orchestral strings was they originally had a gut core (later synthetic/nylon) whereas guitar strings were made using a steel core. The different design approaches are directly related to the fundamental purpose of the string in relation to the instrument. Orchestral string energy is generated by the action of bow, where the string requires more intentional damping and control. Conversely, an electric guitar string is designed to vibrate and excite the instrument’s top or a pickup, which the steel core is more suitable for. Ever try to play an electric guitar with a bow?  Jimmy Page did it to haunting effect, but a roundwound, steel core string is difficult to control with a bow.

Flatwounds were popular and readily available for electric guitar during its formative years in the 50s and 60s. Some early electric guitar strings might started out as roundwound, but were then partially flattened prior to or during the winding process. This technique was common for securing the wrap wire to the core, but the end result was typically not good for players. Strings made like this would have been choked, stiff and dead sounding. Flatwound strings offered a better, more comfortable playing experience and many great recordings from the 50s and early-mid 60s were made on flatwounds. This era could be called the golden age of jazz guitar when legends like Wes Montgomery, Kenny Burrell, Grant Green, Jim Hall, etc. all developed their unique and definitive sounds playing flatwounds. The warmth and smooth feel of flatwounds created a frictionless and focused fundamental tone that defined and memorialized an entire genre. 

D’Addario’s Flatwound History

D’Addario’s history with flatwounds dates back to the early 50s, when John D’Addario Sr. (Jim’s father) made bass fiddle strings for other string brands. Jim D’Addario, now making strings under the D’Addario brand name, started experimenting with flatwounds in 1975 and with some help and guidance from Pat Metheny in ’76-’77 (Pat was looking for a brighter and more consistent flatwound string), perfected what is now known as Chromes. Further advancements in our flatwound machinery has positioned D’Addario as the technology innovator in flatwound guitar strings.

The Flatwound Factors

Back to business… so, what is it about flatwounds that make them so unique and preferred by some?  Most of it comes down to construction. Flatwounds are similar in some ways to a roundwound string, but very different in other ways. Both strings have a high-carbon steel core wire, but differ in the wrap wire construction. Roundwound strings have a single round outer wrap wire, creating a vibrant, bright tone and textured feel. Flatwounds are wrapped with a flattened “ribbon” wire (picture a spool of bow ribbon made of metal), resulting in a more damped tone and polished smooth, frictionless feel. Additionally, they usually contain an underwiding between the core and outer wrap. 

One of the key results of a ribbon wrap wire is the contact points of each wrap are touching around the entire circumference of the string. While this makes the surface smooth, it also damps the string tone by constricting vibration. The result is less brightness, harmonic complexity, and sustain. Now, in the mind of those who prefer the sound of flatwounds, this is a good thing. Many describe the tone of a flatwound as more focused and controlled. Instead of notes vibrating and sustaining after being struck, they tend to die quicker and have more of a plunky sound (we guitarists like our technical descriptions, don’t we?!). Outside of jazz and early rock-and-roll, flatwounds were also a key part of classic country twang and the surf sounds of the 60s. It wasn’t just ES-175s or L5’s that gave flatwounds their identity, Telecasters and Stratocaster love them, too! 

The next notable difference of flatwound vs. roundwound is string tension and flexibility. Flatwound strings have slightly higher tension at pitch than roundwound strings. For example, a roundwound .052 is estimated to be 21.1lbs of tension (tuned to E on a 25.5” scale instrument), while a flatwound .052 is estimated to be 22.5lbs. Not a huge difference on a per-string basis, but the difference can add up across 3 or 4 wound strings in a set. The flat construction also impacts bending stiffness. A flatwound strings is less flexible and therefore, harder to bend. Again, this isn’t good or bad, it just depends on your style and preference, but when you switch to flatwounds from roundwounds, it can take some getting used to. This tension vs. stiffness example is a good way to demonstrate that the two aspects can be related, but not always. 

Lastly, and perhaps the least important factor, is the wrap wire material, at least as they pertain to electric guitar strings. In the orchestral world (primarily acoustic instruments), you see a wide variety of materials used, including nickel, silver, gold, aluminum, tungsten and more. With flatwound electric guitar strings, the two most common alloys (similar to electric guitar roundwound strings) are stainless steel and pure nickel. At D’Addario, we use stainless steel on our Chromes line, which is ideal for both durability and tone, offering a big more brightness than nickel. 

Not Your Father’s Flatwounds

Today, there is somewhat of a boom in flatwound strings. Gary Clarke Jr. is using Chromes to play aggressive blues/rock and I recall a conversation with the great guitarist/producer Blake Mills who swears by Chromes on his “Cooder-caster” for both live and studio use. There are more and more players starting experimenting and sharing ideas on how to get different tones from their guitars. It’s very refreshing to see curiosity and stylistic innovation helping to shine a light on the classic flatwound. Remember, you don’t have to commit to one thing… even if you are a tried-and-true roundwound fan, test a set on a second guitar or try them in the studio, you might be surprised how much you like them!

Other string articles from Brian Vance:

What Strings Are Best for Jazz?

Acoustic Guitar Strings: What You Need to Know

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