I believe that developing guitar speakers and, for the player, deciding what speaker to use is more of an art than a science.
Obviously, tone related topics are very subjective in nature. I believe that developing guitar speakers and, for the player, deciding what speaker(s) to use is more of an art than a science. For example, when designing a new guitar speaker, even if I achieve every parameter or specification I intended to match, if the sound quality is no good, my efforts were pointless. The same is true for the guitar player when studying specs and selecting which speaker(s) to use.
I am receiving a growing number of calls and emails from players with questions about speaker data and cabinet design, rather than just “tone talk.” I believe there are a couple of reasons that this is occurring. One is because of the vast amount of information readily available online. Another is the sheer volume of great gear available from which the player can choose. Guitar players can find it difficult to make the correct purchasing decisions amidst all the information and choices.
In future articles, I will explain cabinet design software and give a few practical examples. I’ll also explain some of the difficulties involved with designing cabinets for guitar speakers. My goal for these articles is to help you use speaker data and hopefully dispel some popular misconceptions. Forum talk is generally good information, but can sometimes evolve into misunderstanding. I often find insightful and enlightening information online, but keep in mind, not everything you read is true and what works for one person may not work for you.
The first important step in the process is to understand speaker parameters. I only have space for a few in this article, but I plan to expound on others in future articles. In the early ‘70s, several technical papers were presented to the AES (Audio Engineering Society), which resulted in the development of what we know today as the “Thiele- Small Parameters.” These papers were authored by A.N. Thiele and Richard H. Small. Thiele was the senior engineer of design and development for the Australian Broadcasting Commission and was responsible for the Federal Engineering Laboratory, as well as for analyzing the design of equipment and systems for sound and vision broadcasting. Small was a Commonwealth post-graduate research student in the School of Electrical Engineering at the University of Sydney. Thiele and Small devoted considerable effort into documenting how various parameters define the relationship between a speaker and a particular enclosure. T/S Parameters can be invaluable when choosing a speaker, because they give you insight into the transducer’s real performance, as well as the basic benchmarks of size, maximum power rating or average sensitivity.
|T/S Parameters can be invaluable when choosing a speaker, because they give you insight into the transducer’s real performance, as well as the basic benchmarks of size, maximum power rating or average sensitivity.|
Resonance or Fs, measured in Hertz (Hz), is the point at which the weight of the moving mass of the speaker becomes balanced with the force of its suspension when in motion. If you’ve ever heard a piece of string start humming uncontrollably in the wind, you have seen the effect of reaching a resonant frequency. It is important to know this information so that you can prevent your enclosure from “ringing.” With a loudspeaker, the mass of the moving parts and the stiffness of the suspension are the two key elements that affect the resonant frequency. The Fs of guitar speakers is typically 80Hz- 100Hz, which is the lower frequencies of the instrument.
Re or DCR is the DC resistance of the driver measured with an ohm meter. This measurement is almost always less than the driver’s nominal impedance. Guitar players sometimes fear that their amp will be overloaded when they see Re is less than the nominal impedance. Due to the fact that the inductance of a speaker increases with a rise in frequency, it is unlikely the amplifier will often see the DC resistance as its load.
Le is the voice coil inductance, measured in millihenries (mH). The industry standard is to measure inductance at 1,000Hz. As frequencies get higher, there will be a rise in impedance above Re because the voice coil acts as an inductor. An impedance curve demonstrates this effect (speaker impedance versus frequency). Zmax is the maximum impedance that occurs at Fs.
In the next issue I’ll have more terms associated with speaker data, such as Mms, Vas, Q parameters, sensitivity and power handling.
You are welcome to submit your speaker related questions to firstname.lastname@example.org
Anthony “Big Tony” Lucas
Anthony Lucas is a guitarist and Senior Lab Technician at Eminence Speaker LLC, where he specializes in guitar-speaker design and customer support. Big Tony has been with Eminence for over 10 years and is responsible for many well-known guitar speaker designs.
Looking for more great gear for the guitar player in your life (yourself included!)? Check out this year's Holiday Gear Finds!
D'Addario XPND Pedalboard
DR-05X Stereo Handheld Recorder
Wampler Pedals Ratsbane
Created in collaboration with legendary guitarist George Lynch of Dokken and Lynch Mob fame, the Mr.Scary Mod adds an adjustable tube gain stage and an onboard Deep control, which together are designed to enable an amp to have increased sustain while still retaining note definition and dynamics.
LegendaryTones, LLC today announced production availability of its new Mr. Scary Mod, a 100% pure tube module designed to instantly and easily expand the capabilities of many classic amplifiers with additional gain and tone shaping. Created in collaboration with legendary guitarist George Lynch of Dokken and Lynch Mob fame, the Mr.Scary Mod adds an adjustable tube gain stage and an onboard Deep control, which together are designed to enable an amp to have increased sustain while still retaining note definition and dynamics.
Originally released as the Lynch Mod in February 2021, the updated Mr. Scary Mod features the same core circuit as the Lynch Mod but is now equipped with a revised tube mix combo per George’s preference as well as a facelift in a newly redesigned electro-galvanized steel enclosure. As with the Lynch Mod, each run will be limited and the first run in Pumpkin Orange with Black hardware is limited to just 150 pieces worldwide.
The Mr. Scary Mod adds an adjustable tube gain stage on top of the cathode follower position, keeping note definition and articulation while further increasing sustain. Each Mr. Scary mod is meticulously built by hand in the USA, one at a time, and tuned using high-grade components. Equipped with a single ECC81 (12AT7) in the first position and ECC83 (12AX7) in the second, the Mr. Scary Mod can clean up beautifully when rolling down your guitar’s volume, and still adds scorching gain when you roll it back up. This is a gain stage that’s been tuned and approved by the ears of the maestro George Lynch himself.
“The Mr. Scary Mod excels with dynamics and is incredibly touch-responsive, allowing me to shift from playing clear, lightly compressed cleans to full-out aggressive sustain and distortion –and control it all simply by varying my guitar’s volume control and picking,” said GeorgeLynch. “In many ways, it’s an old-school approach, but it’s also so much more natural and expressive in addition to being musically fulfilling when you can play both the guitar and amp dynamically together this way.”
The Mr. Scary Mod installs in minutes, is safe and effective to use, and requires no special tools or re-biasing of the amplifier. Simply insert the module into the cathode follower preamp position of compatible amplifiers (includes Marshall 2203/2204/1959/1987 circuits) and
immediately get the benefit of enjoying a hot-rodded amp that delivers all the pure harmonic character that comes with an added pure tube gain stage. The handmade in the USA Mr. Scary Mod is now available to order for $319.
For more information, please visit legendarytones.com.
October Audio has miniaturized their NVMBR Gain pedal to create two mini versions of this beautifully organic-sounding circuit – including an always-on gain device.
The NVMBR Gain is a nonlinear amp that transitions gracefully from clean boost to overdriven tones. Volume increases from just over unity to about 10db before soft-clipping drive appears for another 5db of boost. Its extraordinary ease of use is matched by outstanding versatility: you can use it as a clean boost, push a stubborn amp into overdrive or create a just-breaking-up sound at any amp volume.
October Audio’s new family of mini NVMBR Gain pedals includes a switchable version that allows you to bypass the effect: one option features brand logo pedal graphics, while the other sports a fun “Witch Finger” graphic with a Davies knob as the“fingernail”.
The second version in the new lineup is an always-on device featuring the Witch Finger graphic and Davies knob, with the same NVMBR Gain circuit that lies at the core of the switchable version.
- Knob controls gain and clipping simultaneously
- Stunning silver hammertone finish
- Switchable versions are true-bypass, available with classic or witch finger graphics
- Authentic Davies knobs, including the “fingernail”
- 9V center negative power supply required
- Dimensions: 3.63 x 1.50 x 1.88 in
Witch Finger (always on NVMBR Gain) demo
All October Audio pedals are assembled in Richmond, VA, and available for purchase directly through the online shop. Street price is $109 for NVMBR Gain footswitch versions and $89 for the always-on device.
For more information, please visit octoberaudio.com.