The Q parameters are very important in cabinet design. They represent measurements related to the control of a speaker’s suspension when it reaches the resonant frequency
In this month’s column, I’ll continue with more on speaker parameters. As previously stated, the goal is to help you use this data in selecting speakers and, for the increasing number of DIY’ers, designing your cabinets. Last month, we explored the origins of T/S parameters and discussed Fs, Re, Le and Zmax.
The Q parameters are very important in cabinet design. They represent measurements related to the control of a speaker’s suspension when it reaches the resonant frequency (Fs). They are expressed as Qms, Qes and Qts. The suspension must prevent any lateral motion that might allow the voice coil and pole (or core) to touch. The suspension acts as a shock absorber. Qms is the mechanical Q, which measures the control from the speaker’s mechanical suspension system, the surround and spider. Think of these components as springs. Qes is the electrical Q, which measures the control from the speaker’s electrical suspension, the voice coil and magnet. Opposing forces from the mechanical and electrical suspensions act to absorb shock. Qts is the total Q of the speaker and is derived from an equation where Qes is multiplied by Qms. The result is divided by the sum of the same.
This value can be used as a general guideline in selecting the optimal enclosure type. A Qts of 0.4 or below indicates a speaker well-suited to a vented enclosure. A Qts between 0.4 and 0.7 indicates suitability for a sealed enclosure. A Qts of 0.7 or above indicates suitability for free-air, semiopen back or infinite baffle applications. However, there are certainly exceptions and you should consider all the parameters.
Cms is the force exerted by the mechanical suspension of the speaker. Simply stated, it is the compliance or stiffness of the cone surround and spider, measured in meters per Newton. Considering stiffness (Cms) in conjunction with the Q parameters gives rise to the kind of subjective decisions made by car manufacturers when tuning cars between comfort and precision. Think of the peaks and valleys of audio signals like a road surface and then consider that the ideal speaker suspension is like a car suspension that can traverse the rockiest terrain with racecar precision and sensitivity at the speed of a fighter plane. It’s certainly a challenge! Focusing on one parameter can have a detrimental effect on the others. It’s much like sacrificing one tonal characteristic for another. For example, if you want increased low end, you can expect to give up some output or sensitivity.
Vas represents the volume of air that, when compressed to one cubic meter, exerts the same force as the compliance (Cms) of the suspension. Vas is tricky to measure because air pressure changes relative to humidity and temperature. A precisely controlled lab environment is essential. Basically, Vas shows how much spring the speaker has relative to its surface area. This parameter is useful in determining the enclosure volume, but (dissolving a common misconception) it is not the volume required for the enclosure.
Xmax is the maximum amount of linear excursion expressed in mm. It is measured in one direction of travel. Eminence has always been conservative on this and indicates it by subtracting the top plate thickness from the voice coil winding height and dividing by two. This represents the overhang of voice coil wire on either side of the magnetic gap. As the voice coil begins to leave the magnetic gap, the speaker output becomes non-linear. Although suspensions can create nonlinearity in output, the point at which the number of wire turns in the gap begins to decrease is when distortion starts to increase. Guitar speakers typically use shorter voice coil heights. One reason is that some distortion is often desirable.
Sd is the actual surface area of the cone, normally given in square cm.
Vd (no, it’s not something you caught in college) is the volume of air the cone will move, or the Peak Diaphragm Displacement Volume. It is calculated by doubling the Xmax then multiplying the result by Sd. It is expressed in cc. A higher Vd is more desirable for sub-bass.
Mms is the combination of the weight of the cone assembly, plus the driver radiation mass load. The weight of the cone assembly is simply the sum of the weight of the cone assembly components. The driver radiation mass load is the weight of the air that the cone will have to push (amount calculated in Vd).
In the next issue, I’ll discuss Rms, Bl, EBP, usable frequency range, power handling, sensitivity and hopefully, begin introducing some box designing tips related to guitar applications.
Anthony “Big Tony” 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.
Kick off the holiday season by shopping for the guitar player in your life at Guitar Center! Now through December 24th 2022, save on exclusive instruments, accessories, apparel, and more with hundreds of items at their lowest prices of the year.
We’ve compiled this year’s best deals in the 2022 Holiday Gift Guide presented by Guitar Center.
Looking for a compact, “noiseless” way to plug in and play guitar? Check out the brand-new Gibson Digital Amp, available only in the Gibson App.
The new Gibson App simplifies the learning process and brings guitar playing to life for the current and next generation of guitarists in a modern, comprehensive, and intuitive way. The Gibson App is the place to take your guitar playing to the next level. New to the Gibson App is the Gibson Digital Amp, the ultimate starting amplifier for beginners and a flexible amp on-the-go for intermediate players and pros to get their sound anywhere. The Gibson Digital Amp is an accessible amplifier for both acoustic and electric guitars, and is currently available for Apple/iOS users--an Android version will debut next year.
Use the Gibson Digital Amp’s jamming guide to get started and transform your sound with built-in effects and pedals, jam to backing tracks, or use it in lessons and songs. The Gibson Digital Amp only requires your phone, and wired headphones for the best playing experience, no cables are needed. The amp features 3 acoustic mic presets, 4 electric amp presets, and 6 effects pedals.
The Gibson Digital Amp is the ultimate starting amplifier for beginners and a flexible amp on-the-go for intermediates and pros.
The Gibson App uses a unique two-way, interactive platform to teach guitar students how to do everything from playing their first note to shredding loads of songs. The Gibson App features interactive lessons with thousands of lessons and songs. Learn the songs step-by-step with video tutorials from superstar artists and pro guitarists in the “Gibson App Guide.” The Gibson App also includes the new Digital Amp, a built-in tuner, a metronome, Gibson TV, and new songs are added every week. New Gibson App Guides are added regularly and include Tommy “Spaceman” Thayer’s favorite iconic KISS guitar solos, Richie Faulkner’s (Judas Priest) “Guide to Metal,” Jared James Nichols’ “Guide to Blues,” CELISSE’s “Guide to Songwriting,” and more.
The Gibson App uses “audio augmented reality” to provide dynamic feedback to students as they learn and play. As you pluck a note or strum a chord, the Gibson App listens to your guitar and gives you real-time feedback on your playing. It also gives students a more contextual learning experience: Instead of learning chords and scales in a vacuum, you’re able to practice on a scrolling tablature that lets you hear how you sound with the backing of a virtual band. That means you can load up “Hurt” by Johnny Cash, “Brown Eyed Girl” by Van Morrison, “American Girl" by Tom Petty, “Nothing Else Matters” by Metallica, “Where is My Mind" by Pixies, “Country Roads” by John Denver, “I Hate Myself For Loving You" by Joan Jett, “Heaven” by Kane Brown, “Shape Of You” by Ed Sheeran, “Killer Queen” by Queen,“ Sweet Child O’ Mine,” by Guns ‘N Roses, “Run to the Hills” by Iron Maiden, “Roxanne” by The Police, and “Don’t Stop Believin’” by Journey, “Smells Like Teen Spirit” and “The Man Who Sold the World” by Nirvana, “Are You Gonna Go My Way” by Lenny Kravitz, and “Don't Look Back In Anger” by Oasis and hundreds more songs in a wide range of genres, to see how your play matches up with such seminal tracks.
As you’re playing, the Gibson App gives you feedback on timing and tone, ensuring that students are getting active input on how their play is developing. The Gibson App appeals to players of all levels, it’s not just for beginners looking to learn a few chords; the app can assist seasoned guitarists who are working their way through difficult riffs, want to learn their favorite songs, or polish their advanced techniques.
Players can also challenge themselves by speeding up or slowing the tabs. Like having a full-time guitar teacher, the Gibson App keeps track of all your progress and adjusts lesson plans accordingly. The Gibson App released a “backing track mode” which supports both lesson and song playback without headphones, so users can self-select what works best for their current environment. And that’s not all: the Gibson App also packs in a fully-featured digital tuner for guitar first-timers, there’s even a detailed lesson on how to tune your instrument, a multi-function metronome, players can connect to free one-on-one consultations with Gibson’s Virtual Guitar Tech team, and to direct links to the Gibson, Epiphone, and Kramer online stores for easy shopping for guitars, gear, apparel, and accessories.
Learn Guitar With The Gibson App
The Gibson App is more than a pocket-sized guitar teacher, it’s loaded with an archive of exclusive content and original programming from its premium and accessible award-winning online network, Gibson TV, featuring music icons telling their best guitar stories, with more episodes and installments added regularly. Users can watch Black Sabbath’s Tony Iommi share insights and tales from his decades-long career on the series “Icons,” dive into Joe Bonamassa’s assortment of legendary Les Paul guitars on “The Collection,” or see how Gibson’s iconic instruments are made in their Nashville factory from body to binding on “The Process.” There’s even a series called “The Scene” that focuses on backstage stories from hallowed music venues from coast to coast like The Troubadour and Grand Ole Opry.
The Gibson App free version features a few lessons a day; the premium version of the Gibson App offers full access and a 14-day free trial, then costs $19.99/£16.49 monthly or $119.99/£98.99 yearly.
For more information, please visit gibson.com.
This pickup captures the clear, bell-like single-coil chime of a classic P-90 when played clean and retains the tight mids and articulate low-end vintage growl and smooth sustain saturation when pushed into overdrive.
Belltone Guitars, as part of their Custom-Select System curated offering of pickups, has partnered McNelly pickups to create a one-of-a-kind retro-vibe P-90 pickup in the standard Filtertron size format. This pickup captures the clear, bell-like single-coil chime of a classic P-90 when played clean and retains the tight mids and articulate low-end vintage growl, and smooth sustain saturation when pushed into overdrive.
The McNelly P-90 Foil-Coil comes housed in a ‘raw’ nickel outer casing with a dull nickel foil face with metal mount screw gromets to complete the ‘new-vintage’ aesthetic, making it a perfect choice for your signature Belltone custom build. Available exclusively through Belltone Guitars.
Check out the Custom-Select System belltoneguitars.com to preview the McNelly P-90 Foil-Trons and all our standard and selectable components available to create your own signature Belltone. Then visit the Dream Lab on our website and select either model B-Classic ONE with its top binding or B-Classic TWO with its arm and body contours select your body color from our wide range of offerings, select your neck profile of either standard ‘C’ or thicker ’59 Round Back and either Maple or Rosewood fingerboard followed by your tuners, pickguard, and strings. Finally, review our curated custom-designed, and unique pickup selection to locate the McNelly P-90 Foil-Trons to complete your signature build.
Builds start at just over $2,300.00 with a custom case and shipping included.
For more information, please visit belltoneguitars.com.
McNelly P 90 Foil Tron video Sep27
Belltone P-90 Foil-Tron Pickup
DiMarzio, Inc. announces the Relentless P (DP299), the Relentless J Bridge (DP301), Relentless J Neck (DP300), and the Relentless J Pair (DP302) for 4 string basses.
DiMarzio, Inc. announces the release of the Relentless P (DP299), the Relentless J Bridge (DP301), Relentless J Neck (DP300), and the Relentless J Pair (DP302) for 4 string basses. The new Relentless P and Relentless J series pickups feature the Relentless cover designed in collaboration with Billy Sheehan.
As with the Relentless pickups, we removed all the hard edges from the standard P Bass and standard J Basspickups, and added an arch to the top of the pickups to bring the sensing coils and pole pieces closer to the strings. These improvements increase the dynamic range and make active circuitry unnecessary.
The Relentless P and Relentless J pickups incorporate Neodymium magnets and produce 70 percent more output than traditional passive pickups, and they’re dead quiet due to the incorporation of metal covers and foil-shielded cables. To dial in (or fine-tune) the individual string output, the Relentless P and Relentless J include eight adjustable pole pieces. These pickups also have a broad magnetic field so you can even bend notes without volume dropout.
DiMarzio’s extra shielding makes the Relentless P and Relentless J better for both recording and stage performances. We’ve mounted them onto robust .09375” thick circuit board base plates to eliminate the annoying protruding mounting screws — ultimately creating a more comfortable and consistent foundation to rest your fingers on.
The new Relentless P steps beyond the traditional P-Bass sound and can only be described as massive. It has more of everything: more volume, beefier lows, a growling midrange, and crispy highs with better individual string definition.
The Relentless J incorporates a new invention, (patent pending) parallelogram-shaped coils, offering an expanded mid-range punch, snappy highs, precise lows, and a new dimension to the sound of the Relentless series pickups.
Relentless P and Relentless J pickups will breathe new life into any bass, increase playability, and work well for any style of music from Motown to metal.
DiMarzio’s Relentless P, Relentless J Bridge, Relentless J Neck, and Relentless J pair are made in the U.S.A. and may now be ordered for immediate delivery.
Suggested List Price for the Relentless P is $169.00 (MAP $119.99).
Suggested List Price for the Relentless J Bridge and Relentless J neck is $155.00 (MAP $109.99).
Suggested List Price for the Relentless J Pair is $296.00 (MAP 209.99).
For more information, please visit our website at dimarzio.com.