Rotosound RS665LB Medium Light Bass Strings Review: The Sound That Defined Rock ‘n’ Roll

There’s a moment every bassist experiences. You’re in the rehearsal room, locked in with the drummer, but something is missing. Your lines are solid, your amp is dialled in, but your sound just isn’t cutting through the wall of guitars. It feels muddy, indistinct, lost in the sonic shuffle. I’ve been there countless times, tweaking EQ knobs, swapping pedals, all in pursuit of a tone that has presence, authority, and character. The problem often isn’t the instrument or the amplifier; it’s the very first point of contact, the source of the vibration itself: the strings. Choosing the right set isn’t a minor detail; it’s the fundamental decision that shapes your entire sound. For 5-string players, this is even more critical. A weak, flabby low B-string can ruin an entire performance, turning a foundational note into a murky mess. The search for the perfect string set is a quest for a voice—one that can growl, sing, and command attention.

What to Consider Before Buying Bass Guitar Strings

Bass strings are far more than just lengths of wire; they are the soul and voice of your instrument. The material, gauge, and construction method dictate everything from the thunderous punch of a rock anthem to the smooth, mellow pulse of a jazz standard. The primary benefit of investing in a quality set of strings is tonal clarity and consistency. They can transform a good bass into a great one, allowing the natural character of the wood and electronics to shine through. A well-chosen set of strings improves playability, making intricate passages feel more fluid under your fingers, and ensures reliable tuning stability, which is non-negotiable for both studio recording and live performance. Essentially, the right strings are the key that unlocks your instrument’s full potential.

The ideal customer for a set of bright, stainless steel roundwound strings like these is a player who needs to be heard. This includes bassists in rock, funk, metal, and punk bands where the bass needs an aggressive midrange and a clear top end to compete with distorted guitars and heavy-hitting drummers. Players who employ slap and pop techniques will also gravitate towards this type of string for its articulate, percussive attack. On the other hand, these might not be the best fit for musicians seeking a vintage, warm, and thumpy tone reminiscent of 1960s Motown or soul. For that classic sound, flatwound strings are a far better choice. Additionally, players with a very light touch or those concerned about fret wear might prefer a softer material like nickel or a set of coated strings, as stainless steel is known for its abrasive texture.

Before investing, consider these crucial points in detail:

• Gauge & Tension: The gauge refers to the thickness of the strings. The Rotosound RS665LB Medium Light Bass Strings feature a .035, .055, .070, .090, .120 set. This “medium light” configuration provides a taut, clear-sounding low B (.120) while keeping the upper strings flexible and easy to play, which is excellent for complex runs and string bending. Heavier gauges offer more tension and a fatter tone, while lighter gauges are easier to fret and have a brighter sound.
• Tonality & Performance: This is determined primarily by the string’s material and winding. Stainless steel, used in this set, is known for its bright, crisp, and aggressive tone with a pronounced high-end “zing.” Nickel-plated steel strings, a common alternative, are warmer and smoother sounding. The performance you need depends entirely on the musical context you play in.
• Materials & Durability: Roundwound strings, where a round wire is wrapped around the core, offer the brightest tone but have a textured feel. Flatwound strings have a flat, ribbon-like wire, resulting in a smooth feel and a deep, mellow tone. Stainless steel is highly resistant to corrosion from sweat and oils, giving it a long tonal life, though its brightness does mellow over time.
• Feel & Playability: The texture of the string winding directly impacts how it feels under your fingers. The grooves of roundwound strings can be abrasive for some players and can cause more fret wear over the long term. If you slide up and down the neck frequently, you’ll hear more “finger noise” with roundwounds compared to the whisper-quiet glide of flatwounds.

Ultimately, the choice of strings is a deeply personal one that shapes your identity as a player. Understanding these factors will help you find the set that truly speaks your musical language.

While the Rotosound RS665LB Medium Light Bass Strings is an excellent choice, it’s always wise to see how it stacks up against the competition. For a broader look at all the top models, we highly recommend checking out our complete, in-depth guide:

Unboxing the Legend: First Impressions of the Rotosound RS665LB

Opening a pack of Rotosound Swing Bass 66 strings feels like handling a small piece of rock history. The packaging, with its iconic red, white, and blue branding, is unapologetically British and instantly recognizable. Inside the airtight foil pouch, the five strings are coiled neatly. Rotosound uses coloured ball-ends for easy string identification—a simple but brilliant feature that saves time and frustration during a string change. Upon uncoiling them, the first thing we noticed was the distinct texture. These are unabashedly roundwound strings; running a finger along the surface reveals the tightly wrapped stainless steel wire, a texture that promises an aggressive, tactile playing experience. They feel sturdy and exceptionally well-made, a testament to their UK manufacturing origins. When compared to smoother, nickel-plated strings, the difference is night and day. The RS665LB set feels like a high-performance tool built for a specific purpose: to deliver maximum brightness and punch. We made sure to inspect our set carefully, confirming all five strings were present and correct, a good practice as one user noted a rare instance of a missing string in their package.

In the Studio and On Stage: A Deep Dive into the RS665LB’s Performance

A set of strings can look good in the packet, but its true worth is only revealed when strung up and pushed to its limits. We installed the Rotosound RS665LB Medium Light Bass Strings on a 34″ scale 5-string bass with active electronics to see if the legendary tone lived up to its reputation. From the first note, it was clear why this string family has been the choice for icons like John Entwistle, Geddy Lee, and Billy Sheehan. The sound is immediate, authoritative, and brimming with character.

The Auditory Assault: Dissecting the Swing Bass 66 Tone

The defining characteristic of these strings is their incredible brightness and piano-like clarity. The moment you plug in, you’re greeted with a top-end sizzle that makes every note articulate and distinct. This isn’t a subtle warmth; it’s a full-frontal sonic assault that demands to be heard. When playing fingerstyle, the notes have a percussive attack and a long, clear sustain. Digging in with a bit more force unleashes the signature Rotosound growl—a complex, grinding midrange that is the bedrock of classic rock bass tone. This growl is what allows a bass to sit perfectly in a dense mix, occupying its own frequency space without becoming muddy.

Switching to a pick, the character changes again. The attack becomes even more pronounced and aggressive, perfect for punk rock and heavy metal. Every downstroke is a metallic clang that drives the rhythm section forward. For slap and pop players, these strings are a dream. The high-end response provides a sharp, glassy “pop” on the G and D strings, while the slap on the low strings is thunderous and resonant. The stainless steel construction is the key ingredient here; it produces a harmonically rich and vibrant sound that nickel strings simply can’t replicate. While testing, we found that a slight boost in the low-mids on the amplifier really brought out the inherent growl, creating a tone that was both powerful and nuanced. The full harmonic range these strings offer is truly something to behold.

Feel and Playability: A Tale of Two Textures

The physical feel of the Rotosound RS665LB is as distinctive as its sound. The medium-light gauge is a fantastic compromise. The .035 G-string is pliable enough for quick runs and expressive bends, while the .120 B-string provides enough tension to feel solid and responsive under the fingers, avoiding the dreaded “flabby B” syndrome common in lesser sets. This balanced tension across the fretboard makes the bass feel incredibly responsive and dynamic to play.

However, there’s no getting around the texture. The stainless steel round windings are noticeably rougher than nickel-plated or coated strings. For players accustomed to a smoother feel, this can take some getting used to. The trade-off for that brilliant tone is increased finger noise when sliding between notes and a more abrasive action on your fingertips. After a long three-hour session, we could definitely feel the difference on our calluses. This isn’t a flaw, but rather an inherent characteristic of this type of string. For many rock players, this tactile feedback is a positive, providing extra grip for aggressive playing styles. It’s also worth noting that this texture will contribute to fret wear over time more than a smoother string would, a consideration for those with vintage instruments. The unique feel and response are key to their performance, but it’s important to know what you’re getting into.

Longevity and Tuning Stability: The British Workhorse

One of the most debated topics surrounding stainless steel strings is their lifespan. The Rotosound RS665LB set comes out of the packet with an almost overwhelmingly bright zing. This peak brightness, in our experience, lasts for about 8-10 hours of heavy playing before it starts to mellow. Crucially, “mellow” does not mean “dead.” Unlike cheaper strings that lose all their character, the Rotosounds settle into a second life. They lose the initial high-frequency sizzle but retain their powerful midrange punch and fundamental clarity for weeks, even months, depending on your playing frequency and body chemistry. This settled-in tone is preferred by many players, as it’s less harsh and sits in a mix beautifully. As confirmed by one long-time user, Andy of The 58’s Blues Band, these strings have a reputation for being reliable workhorses.

Tuning stability was exceptional right from the start. After the initial stretching phase, which took only about 15-20 minutes of playing, the strings held their pitch remarkably well, even with aggressive playing and temperature changes between rooms. This reliability is a hallmark of Rotosound’s manufacturing process and is absolutely essential for any serious musician. There’s little more frustrating than having to re-tune between every song, and thankfully, that was never an issue during our testing. This dependable performance makes them a superb choice for both studio and stage.

The Low B-String: The Foundation of the 5-String Sound

The performance of the low B-string can make or break a 5-string set. A poor B-string sounds indistinct, lacks fundamental pitch, and feels like a loose rubber band. We are happy to report that the .120 gauge B-string in the RS665LB set is absolutely phenomenal. It is taut, focused, and articulate. Whether playing open B or fretting notes high up the neck, the pitch was clear and the note had a solid, unwavering fundamental. There was no unwanted muddiness or “wolf tones.” This clarity is vital, as the B-string serves as the anchor for the band’s entire low-end. It blended seamlessly with the other four strings, maintaining the same tonal character of bright attack and punchy sustain. When played through a high-gain rig, the B-string remained tight and defined, perfect for modern metal and rock styles. For any 5-string player, the quality of this B-string alone is a compelling reason to consider this specific set.

What Other Users Are Saying

Our positive experience is echoed by many musicians who rely on these strings professionally. Andy, the bass player for The 58’s Blues Band, gives a glowing endorsement, stating, “Ive used these strings for many years, they are the best on the market (in my opinion)”. This long-term perspective from a working musician speaks volumes about their consistency, durability, and suitability for genres like blues and rock where a strong, characterful bass tone is essential. His loyalty suggests that the strings consistently deliver the performance he needs, gig after gig.

However, it’s also important to acknowledge potential issues. One user from Italy reported receiving a package with the A-string missing. While this appears to be a very rare quality control or packaging error, it serves as a valuable reminder. For a brand with a reputation as strong as Rotosound, this is certainly an anomaly, but it highlights the importance of purchasing from reputable sellers and checking the contents of your package upon arrival. This isolated incident doesn’t detract from the overall quality of the strings themselves but is a practical point of feedback for any potential buyer.

How Does the Rotosound RS665LB Compare to the Competition?

While the Rotosound RS665LB Medium Light Bass Strings hold a legendary status, the market is filled with excellent alternatives that cater to different tastes in tone, feel, and aesthetics. Here’s how they stack up against three notable competitors.

1. DR Strings HI-DEF NEON™ Bass Strings Medium 45-105

The most striking difference with the DR NEON strings is their visual appeal. The K3 coating is available in a variety of bright colours that are UV and blacklight reactive, making them a fantastic choice for players focused on stage presence. Tonally, the coating gives these strings a slightly warmer sound and a much smoother feel compared to the raw stainless steel of the Rotosounds. While they are still bright, they lack the aggressive grind and sizzle of the Swing Bass 66 set. Players who prioritize a unique look and a slick, fast-playing feel over raw, traditional tone might prefer the DR NEONs.

2. Rotosound RS77LD Monel Flatwound Bass Strings

This alternative, from Rotosound’s own catalogue, represents the polar opposite on the tonal spectrum. The RS77LD strings are flatwounds, constructed with a Monel 400 alloy, famously used by artists like Steve Harris of Iron Maiden. Instead of a bright, zingy top end, these deliver a deep, percussive, and fundamental-heaving thump. They have a completely smooth, almost glassy feel under the fingers, produce virtually no finger noise, and have an incredibly long lifespan, with their tone improving with age. Bassists playing jazz, soul, Motown, or vintage rock who want a classic, woody, and warm tone would be much better served by these flatwounds than the RS665LB.

3. Ernie Ball Power Slinky Cobalt Electric Bass Strings 55-110

The Ernie Ball Cobalt Slinkys are perhaps the most direct competitor to the Rotosounds in the “bright and aggressive” category. The unique cobalt-iron alloy used by Ernie Ball provides a stronger magnetic relationship with pickups, resulting in higher output, incredible punch, and a very wide dynamic range. They have a similarly bright top end to the Rotosounds but with a different midrange character—some players describe it as more “modern” and “hi-fi.” The feel is also slightly smoother than the Rotosound stainless steel. A player looking for the absolute maximum in output and a modern, aggressive rock tone might lean towards the Cobalt Slinkys.

Final Verdict: Are the Rotosound RS665LB Medium Light Bass Strings Right for You?

After extensive playing and analysis, our conclusion is clear: the Rotosound RS665LB Medium Light Bass Strings are not just a set of strings; they are an institution. They deliver on their promise of a bright, punchy, and articulate tone that has powered countless iconic records. Their UK-made quality ensures excellent tuning stability, and the carefully selected gauges provide a perfect balance of powerful low-end tension and high-end playability. The standout feature is undoubtedly that signature midrange growl and piano-like clarity, which can elevate a bass from a background instrument to a lead voice in the band.

They are, without question, the ideal choice for bassists in the rock, punk, funk, and metal genres who need to cut through a dense mix and make a statement. However, the abrasive feel and the rapid decay of the initial “zing” mean they are not for everyone. If you seek a smooth feel or a mellow, vintage tone, you should look elsewhere. But if you’re chasing that legendary, aggressive rock ‘n’ roll sound and you’re ready to embrace the tactile nature of classic stainless steel, there is simply no substitute. For players ready to inject their 5-string bass with a dose of authentic British thunder, we can’t recommend them highly enough. You can check the current price and find more details right here.