In this video Eric Johnson discusses vintage tone, and how he, along with George Alessandro and Eminence, set out to recreate those classic sounds in this new design. Eric also demonstrates the EJ1250′s ability to deliver very balanced, harmonic tones in various playing styles.
News & Media
Eminence is proud to introduce three advanced high-power additions to the Professional Series: the Impero 12A, 15A, and 18A. Italian for “empire”, Impero sets the tone for this elite offering of high quality, hand-built loudspeakers.
Using high motor strength with balanced Vas and Mms, the Impero series plays extremely loud and low in compact vented designs. Advancements include a 1/2” thick by 7.5” diameter machined top plate, one piece machined T-yoke, and a 4” deep wound fiberglass voice coil. These features combined with an ultra-linear long-excursion suspension and bumped motor assembly allow the Impero series to move serious air, generate serious SPL, while handling tremendous amounts of power.
At 1,100 watts continuous / 2,200 watts program power, the 12” Impero 12A has a usable frequency range of 56 Hz to 3 kHz, making it perfect for two-way top boxes, full-range two-way boxes, bass guitar boxes, and small subwoofers.
The 15” Impero 15A is suited for two-way top boxes, full-range two-way and three-way boxes, bass guitar boxes, and small subwoofers, and is rated at 1,200 watt continuous / 2,400 watt program. With a frequency range of 46 Hz to 2 kHz, this 15” has the extension at both ends to go low and high, perfect for small vented boxes with conventional sized horns. This model is also available in a 4 ohm version, the Impero 15C.
The 18” Impero 18A is also rated at 1,200 watt continuous / 2,400 watt program power, has a frequency range of 39 Hz to 820 Hz, and is suited for full-range three-way boxes, bass guitar boxes, and small subwoofers. This model is also available in a 4 ohm version, the Impero 18C.
“The Impero series has it all while being arguably the most attractive speaker we’ve designed so far.” said Jerry McNutt, Design Engineer at Eminence. “Incorporating CNC machined zinc plated motor parts, water resistant treated cones and dust caps, and sanded-edge cast aluminum baskets, it’s beauty AND the beast.”
Like all Genuine Eminence branded professional audio and musical instrument loudspeakers, the Impero 12A, 15A and 18A are built by hand in the USA, and are backed by our industry-leading 7-year warranty. See the Impero series at the Winter NAMM Show in Anaheim, CA on January 19, 2012.
**Meet Eric Johnson in person at the Eminence NAMM booth on Friday, January 20th at 2:00pm at the Winter NAMM Show in Anaheim, CA.**
Eminence is proud to announce the addition of a signature 12” alnico guitar speaker developed with legendary guitarist Eric Johnson, the EJ1250.
Eminence knows a thing or two about vintage tone, having made guitar speakers for the biggest amplifier brands in the industry since the late ’60s. But one guitarist
is known the world over for defining vintage tone. Working with Eric and George Alessandro, Eminence has designed the first speaker worthy of Eric’s name.
Available in both 8 and 16 ohm impedances, the EJ1250 is a 50 watt, 12” guitar speaker featuring vintage alnico tone with a modern twist. With both American and British characteristics, the EJ1250 delivers punchy lows, warm throaty mids, and articulate highs.
“I’m excited that for the first time in many years there’s a new speaker that I love the sound of.” said Johnson.
“No other guitarist’s name has become synonymous with vintage tone.” said Eminence President Chris Rose. “We’re very excited to be collaborating with him, and the fact he has chosen Eminence to deliver his signature sound is testament to our own reputation for building the highest quality products on the market.”
Like all Genuine Eminence branded professional audio and musical instrument loudspeakers, the EJ1250 is built by hand in the USA, and is backed by our industry-leading 7-year warranty.
Sounds clips and Eric Johnson demo video coming soon.
The following article was written by Anthony Lucas for Bass Gear Magazine.
Are sealed or ported enclosures better for bass guitar? What are the differences between them? In this article, I will compare the two most common types of bass guitar enclosures and try to highlight the benefits and shortcomings of each. It took me a while to decide what details to cover, and I soon realized it might require a book to cover the concepts of cabinet design. It would take a couple of articles this size just to introduce the terminology. For the DIY guys and players interested in obtaining more knowledge, there is a wealth of information available online to learn more about cabinet design. There is also plenty of software available online to help you with calculations. Whether you find information about car audio, home hi-fi, pro audio or bass guitar, the principles are basically the same. This article will be used for the details I feel will help bass players the most.
First, let’s think about the role of the speaker. A speaker produces minimal output in free-air (outside of a cabinet). Sound is produced from the front and the rear of a speaker’s cone. These sound waves must be separated to achieve usable output. If not separated, the output from the front and rear of the cone would cancel each other out. This is further accentuated with lower frequencies, and the main reason for mounting a speaker on a baffle. The baffle also absorbs vibration created by the speaker. If not mounted to a baffle and simply placed on a solid surface, the vibration created from the speaker’s movement may be louder than the sound it emits. A baffle that does not resonate with the speaker must be made from a solid and thick material.
Shaping the low-end (bass frequencies below 300Hz) is the reason for choosing a particular enclosure type. A speaker’s cone response dictates the signature shape or sound of the enclosure beyond 200-300Hz (figure 1). Any speaker will produce sound in any cabinet, but optimizing the relationship between the speaker and the enclosure is the key to good bass. In the early ‘70s, two engineers, named A.N. Thiele and Richard H. Small, devoted considerable effort to show how specific speaker parameters define the relationship between a speaker and a particular enclosure. These are known today as Thiele-Small (or T/S) parameters. They are a means of comparing speaker performance and finding optimal cabinet conditions.
Speaker designers manipulate T/S parameters when customizing a speaker for a particular cabinet or when meeting certain design goals. I’ll leave the specifics about T/S parameters and how they are interconnected for another day. But, for now know that trade-offs are involved in every aspect. If you want deeper bass, punchier bass, tighter bass, more snap, pop, or whatever the desirable adjective, something else will be sacrificed to obtain it. Every amp and cabinet manufacturer has methods to achieve their signature tone. Speaker performance and cabinet design are equally crucial parts. Designers must prioritize what performance or sonic characteristics they desire from a product and determine what aspects of the speaker and cabinet will make it a reality. Output level (or SPL), power handling, frequency range, and size and weight are all considerations. When one is improved, other factors may suffer. The most difficult part is finding a middle ground. We want to have it all, but unfortunately, it’s not always so simple.
Here’s how a sealed enclosure works. The back of the speaker is completely sealed off from the front. The air inside the enclosure acts as a spring, which helps control the movement of the cone. When the speaker moves out, the pressure inside is decreased. When the speaker moves in, the pressure inside is increased.
A sealed cabinet is considered a punchier, more accurate sound. Sealed cabinets are much easier to design and build than ported enclosures and are typically smaller in size. There is also much more room for error in design and construction because a small change to the internal volume doesn’t affect the lowest audible frequency significantly (Figure 2). You might often see the low range or note of a cabinet’s specifications defined as F3 or F10. Mid-band response is basically an average level of the speakers’ or cabinet’s overall output within the usable frequency range. F3 is the frequency 3dB down from the mid-band and F10 is the frequency 10dB down from the mid-band (see Figure 3). Sealed enclosures have better transient response, which means the system will respond more quickly to a sudden change. This is one reason why they sound punchier and more accurate. When you’re playing a run, it sounds more articulate with better note separation. Sealed enclosures also have good power handling capability and gradual frequency roll-off.
The disadvantages of sealed enclosures are lower efficiency and poor deep or extended bass output. The sealed design will never play as low as the resonant frequency of the speaker. It seems like the easy answer would be to design speakers for sealed enclosures with low resonant frequencies, right? That’s certainly one part of the puzzle, but a lower resonant frequency can negatively impact other design and performance goals. Speakers with lower resonant frequencies are typically low in output and narrow in frequency range. Another disadvantage is higher distortion. Maximum cone movement occurs at the resonant frequency of the enclosure (Fc). Basically, the speaker is working harder where the cabinet is most demanding. Dampening improves below Fc, so control of the cone and mechanical power handling of the speaker are good.
Ported enclosures are also referred to as vented, or bass-reflex enclosures. This design requires a more scientific approach, and there is less room for error in design and construction. Ported cabinets allow for an extended bass response. The result sonically is more “rumble” and deeper bass tone. A port (or vent) is used to tune the enclosure to a specific frequency (Fb). The surface area and length of the port are crucial to the tuning. The Fb of the enclosure does not change with speaker selection, but F3 does. The port uses the speaker’s rear output to enhance the speaker’s front output, which increases bass output (or SPL) above F3 (see Figure 3 again). This minimizes the movement of the speaker cone, so mechanical power handling at and above the tuning frequency is very good. The port is actually producing most of the output at the tuning frequency and the speaker’s excursion is minimal. Distortion is lower at this point due to less cone movement.
There are some disadvantages to ported enclosures. Transient response is poor compared to a sealed enclosure. The result is decreased accuracy. Also, there’s less control below the box tuning, which allows the cone to move more freely. This can result in damage to the speaker mechanically, a phenomenon known as over-excursion.
A poorly designed ported enclosure can cause all sorts of problems. Tuning the enclosure too high can be a problem. This can create a ringing at Fb and result in a one note wonder with inadequate frequency range (Figure 5). While mechanical power handling is typically a good advantage of a higher tuning, remember that the enclosure is not helping the speaker below Fb. If there is a sudden peak at a lower frequency there could be a potential for over-excursion problems. The speaker’s cone will literally jump out of the box. Low tuning can also generate problems. A large enclosure is required for a lower tuning. This can severely lower the speaker’s mechanical power handling. Loose, rumbling bass with no definition or “punch” may be the result sonically. You sacrifice the effectiveness of the cabinet and the speaker (refer to Figure 4, Figure 4-1 and Figure 4-2). The F3 of a smaller cabinet that is tuned too low will be very high. Sure, transient response and punch will improve, but at this point, it’s more effective to use a sealed enclosure.
A port without adequate surface area can create unwanted noise at higher volume… even when the tuning and size of the enclosure is good for the speaker. If the velocity of the air travelling through the port is too high, a noise often referred to as “chuffing” may occur.
We live in a day where power is relatively cheap and high power handling is a big selling point. Whether it’s the enclosure or the speaker, be aware that there are other specs to consider before you make a purchase. High power handling and lower output may not be the best bang for your buck. In contrary, a high SPL enclosure or speaker may not require as much amp to reach the desired volume levels. Factors for high a high output cabinet are the speaker’s SPL, power handling, and size, and a cabinet that is well built and free from air leaks.
A parameter called EBP (calculated by dividing FS by Qes) is often used to determine if a speaker is best suited for a sealed or ported enclosure. An EBP close to 100 usually indicates a speaker is best suited for a ported enclosure. An EBP closer to 50 usually indicates a speaker is best suited for a sealed enclosure. A speaker with an EBP 50-100 might work well in both types of enclosures. This is purely a general rule of thumb. Many great designs violate this.
You will often hear me talk about modeling a cabinet. I use software to calculate or predict a speaker’s performance in a given cabinet. It is an invaluable tool for cabinet designers and for recommending speaker components. The graphs used in this article are the result of one of those tools. Of course, anytime you’re dealing with TONE, there’s some voodoo or black magic involved. I’ve seen many successful designs that didn’t look so good on paper. There is definitely some art and science involved in the voicing and EQ of the amplifier. I also believe that sometimes you just get lucky and find that perfect combination of speaker voicing, cabinet, amp, and instrument and it just doesn’t matter if it works out technically. See you next time.
Eminence Speaker LLC proudly announces an exclusive license agreement with Evenstar, a wholly owned subsidiary of SLS Audio, to use and sub-license their revolutionary new D-fend™ technology within the Professional Audio and Musical Instrument markets.
D-fend™ is the industry’s first all-digital, programmable loudspeaker protection and attenuation circuit designed to solve the age-old problems associated with protecting loudspeakers from excessive power conditions. D-fend™ has eliminated the headaches for speaker engineers – no more hassling with polyswitches, blown lamp filaments, lossy resistors, or slow relays. Incorporating such features as digital signal processing with on-board digital filtering, customizable microprocessor and MOSFET construction, the D-fend™ protection circuit enables a designer to use this technology prior to passive filtration and allows different sensitivity settings in specific frequency bands, such as woofer over-excursion bands or high frequency peak damage regions.
“Think of the D-fend circuit as a high power, speaker-level compressor/limiter that will allow an audio designer to guarantee unmatched levels of protection for multiple components in their unpowered loudspeakers”, states Evenstar’s Chief Engineer, Joel Butler.
“We’re are very excited about the unique opportunity to partner with Evenstar to offer our customers the ultimate in loudspeaker protection.” said Eminence President Chris Rose. “Not even the most carefully designed systems have been free of failure and the risk of thermal compromises in today’s varied applications. By incorporating D-fend in their products, system designers, brand owners and facilities will enjoy a new level of assurance that their passive loudspeaker systems will remain protected and that venues will be safer. The technology is economical and easy to integrate into both new and existing designs. We expect it will become an industry standard protection device for virtually all passive professional audio and musical instrument applications.”
See the D-fend™ technology in action at the Eminence InfoComm booth #164 in Orlando, Florida June 15 – 17, 2011, or contact Josh Martin, Technology Sales Manager, at 502.845.5622 ext. 245, or via e-mail to email@example.com for more information.
Speaker break-in is no myth and something significant really does happen. All speakers are built to meet certain specifications, and we work diligently through QC efforts during and after production to ensure that happens. Every component used in a speaker has tolerances, which can relate to small variances in initial performance. The mechanical properties of a speaker are slightly modified once a speaker is put into service, and the tone is affected by these changes. Speaker break-in is a natural process that is influenced by how much you use the speaker and how loud you play it. Think of a new pair of shoes. They are not most comfortable right out of the box. They feel best after you have worn them for a while, softened up, and formed to your feet. Much like your new pair of shoes, new speakers need time to “break in”, and will not sound best until they do.
The components making up the speaker’s suspension are primarily what changes during break-in. These components are the spider (lower suspension) and the cone surround (upper suspension). As the speaker is used, the spider and cone surround begin losing some of their initial stiffness. The sonic results you will hear are an increase in overall warmth, slightly deeper/fatter lows, and warmer/smoother highs. Subtle changes will continue throughout the life cycle of the speaker, but the most noticeable amount occurs in the early stages of use.
The duration of time required to achieve break-in will vary between speakers. Your environment can affect speaker break-in as well. It may take longer in a cold, dry climate versus a hotter, more humid environment. Again, your usage and volume will also affect break-in time. There are several methods people use to speed up the process, but these methods can be damaging to the speaker and are not recommended. The best method is to simply play your new speaker at normal to high volume as frequently as possible. You may even find it is fun and enlightening to experience the changes in your speaker as it breaks in!