News & Media

Eminence Speaker Seals a Great Deal

April 23,2012

Expanding on the success of their ultra-popular Alpha 6A professional audio loudspeaker, Eminence Speaker LLC proudly introduces a sealed chassis midrange version, the Alpha 6CBMRA.

Alpha 6CBMRAFrom the high-performance and high-value American Standard series, the Alpha 6CBMRA is a 100 watt, 6.5" mid/woofer with a usable frequency range of 400Hz to 5kHz. The sealed, stamped steel basket eliminates the need for separate sub-enclosures.

"Many Alpha 6A users told us numerous times their applications require a true midrange, asking repeatedly to make a closed back version." said Jerry McNutt, Design Engineer at Eminence. "We listened. We delivered!"

With its sealed basket and smooth frequency response, the Alpha 6CBMRA is perfect for pro audio enclosures or cars while keeping acoustic integration with your system simple. Based on the same great Alpha 6A heritage, the power handling, simplicity and performance of the Alpha 6CBMRA leave it second to none.

See more product details here.

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Understanding Loudspeaker Power Ratings

Tech Talk With Big Tony March 15,2012

Speaker power handling must be the most misunderstood specification in our industry.  Knowing the power handling of a speaker is rather useless without considering other specs and details.  It’s like knowing the “what” without the “when” or “where.”

Eminence uses an industry standard method (EIA 426A) for establishing power ratings. A speaker is tested in free-air with a continuous noise signal with a 6dB crest factor.  This continuous average power rating (or “watts” rating) is basically a thermal limit.  Eminence does not associate a watts rating with “RMS.”  RMS pertains to voltage or current, but “RMS watts” is an erroneous term.  The music program rating is always twice the continuous rating.  It is a higher rating because music has many peaks and dips and is not as abusive as a continuous signal.  This is a good rating to select amplifier power for proper headroom in a pro audio application.  Eminence does not publish a peak rating, but we accept it as four times the continuous rating.  Peak is higher because the shorter duration of a burst of sound is less abusive than a music signal or a continuous signal.

Power testing is performed on all Eminence branded speakers offered on our website.  We also manufacture products for OEM (original equipment manufacturer) companies, which may or may not carry the “Eminence” name.  These products are custom designed to a manufacturer’s specifications and are not power tested or rated by Eminence.  It is at the discretion of our customer to test and rate their amp or cabinet, but rating the speaker may not be a concern for them.  For instance, if a certain speaker works to the satisfaction of a manufacturer in a 300 watt product, it’s insignificant if the speaker can actually handle 500 watts.  The cabinet or amp containing the speaker will get the 300 watt rating.  The more important concerns of the cabinet or amp manufacturer are how well the speaker performs mechanically and sonically.  The mechanical performance involves how well the T/S parameters of a speaker align with the enclosure.

Mechanical power handling becomes the real issue when you consider a speaker for a specific cabinet.  Keep in mind, it can never exceed the thermal power handling because the speaker would fail first.  A speaker’s mechanical power handling will vary in different cabinets and is dependent on the cabinet volume and the tuning frequency (if ported). Larger cabinets and lower tunings, for example, are both more abusive conditions and will decrease the mechanical power handling of a speaker.  Woofers (a speaker designed to produce lower frequencies) are particularly more cabinet dependent because bass frequencies are more abusive. Lower frequencies require the woofer to move more air.  In applications where low frequency reproduction is a requirement, it might actually take a 500 watt woofer to handle 300 watts of amplifier power.  This is common in bass guitar and pro audio subwoofer applications

T/S parameters will help you ensure whether or not a speaker is suitable for your cabinet and amp power. They can also help you determine the mechanical power handling of a speaker in your cabinet.  Xmax and sensitivity (or SPL) are a couple of parameters that are so often overlooked.  Xmax is especially important for pro audio and bass guitar applications.  This parameter represents the maximum linear excursion, or in simple terms, how far the speaker can travel before reaching harmful levels of distortion.  A speaker with more Xmax has greater excursion capability (or travel), which basically means it can produce lower bass at higher volumes.  Xmax is crucial to a speaker’s mechanical power handling when the application requires low frequency reproduction.

SPL represents how loud a speaker is and provides another means to compare speakers.  A speaker with a higher SPL will not require as much amp power to achieve a certain volume.  We have found that many people use the high SPL of our pro audio speakers to their benefit for applications such as bass guitar, car audio, and home hi-fi.  The demanding low frequency bandwidth of these applications may often limit a speaker’s mechanical power handling significantly, but the higher SPL can be a huge advantage in several ways.

One example is a pro audio woofer used as a car audio or home hi-fi subwoofer.  A 500 watt woofer may be reduced to a 100 watt woofer if asked to produce a signal anywhere from 20-40Hz.  However, this could be an effective approach if the woofer can produce this signal at 96dB with one watt of power.  In another example, it is often more beneficial to use a high SPL, full range type woofer over a true low frequency woofer for a bass guitar application.  The true low frequency woofer would provide better mechanical power handling in the cabinet, but could be too narrow in bandwidth, resulting in a lack of mids and highs.  It may also require more amplifier power to achieve a desirable volume.  A higher SPL, more full range type of woofer will produce better mids and highs and the overall output is higher per watt.  As previously described, it may take a 500 watt rated speaker to handle 300 watts of amplifier power.

Mechanical versus thermal power handling is not a significant topic for open or closed back, lead/rhythm guitar applications.  The standard guitar frequencies are not that abusive on a speaker, so guitar speakers are not as cabinet dependent as pro audio or bass guitar speakers.  The important factors for selecting a guitar cabinet are based more on how the size and materials affect or add to the tone.

At this point, you might be thinking why Eminence would publish such a useless rating?  Well, a thermal power rating gives you an idea of a speaker’s potential and a way to compare to other speakers.  Most of our speakers are multi-purpose and we don’t know how or where they might be used.  End users often use our speakers effectively in ways that we never thought about, and we encourage it!

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Eric Johnson on the Eminence EJ1250

February 27,2012

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.

Learn more about the EJ1250.

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Eminence Adds Three Advanced High-Power Loudspeakers to the Professional Series.

January 12,2012

Impero Series

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.

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Eminence and Eric Johnson Team Up to Deliver 50 Watts of Pure Vintage Tone.

January 4,2012

**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.

Eric Johnson Signature EJ1250Available 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.


Download spec sheet

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Jon Bloomer at GuitarNoize.com Demos a Governor and Man o War

January 4,2012

Here’s another great demo from our good friend Jon Bloomer at Guitar Noize. In this demo, Jon uses one of our most popular combinations of 12″ speakers, the Governor and the Man O War, both from our British-voiced Red Coat Series of guitar speakers.

“The frequency response of each of these speakers are slightly different, The Governor has a great classic speaker response with a nice full and even tone whereas the Man O War is more pronounced around the 1kHz range and you can hear that in the Overdriven guitar parts in my demo in particular. The Man O War also seems a little tighter and is well suited to heavier Rock and Metal. When you blend these speakers together you get the best of both worlds resulting in a detailed punchy tone great for any genre you throw at them. I tried to show this in my demo video by layering clean, crunchy and high gain overdriven guitars on top of a Jamtrackcentral.com backing track. For each part I placed a single Audix i5 Dynamic Mic on the edge of the dust cap a couple of inches off the grill cloth. I used my Suhr Modern and Ceriatone Chupacabra 50 amp in 60′s mode for the clean rhythm guitars and added the Suhr Shiba Drive for the clean solos. For all other guitar parts I used the 80′s mode and added the Shiba Drive for the Overdriven lead guitars.”- Jon Bloomer | GuitarNoize.com

Check out more of Jon’s great posts at GuitarNoize.com

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Interview with Steve Ouimette

November 21,2011

Steve OuimetteChances are, if you’ve turned on a TV, radio or video game console within the last several years, you’ve likely heard the infectious music of Steve Ouimette. From his awe inspiring work behind the epic Guitar Hero video game series, to his composition and song writing heard in many popular TV shows and studio recordings, Steve is quickly becoming known for the creativity he brings to every project. With the myriad of options available to recording artists today, one thing remains consistent in Steve’s tone toolbox – Eminence speakers. We had the pleasure of catching up with Steve recently, here’s what he had to say.

Eminence: Was the guitar your first instrument? When did you first pick it up?

Steve: I wish I could say it was but my first instrument was the organ. My parents had bought one and signed my sister and me up for lessons. I did that for 2 years from 5-7. When we moved to California I started playing drums but I was more Bobby Brady than John Bonham so around 11 or 12 I switched to guitar. It was Ace Frehley who originally inspired me. After that it was Van Halen, Randy Rhoads, Yngwie and Angus Young.

Eminence: At what point in your life did you decide you were going to make a career out of your musical abilities?

Steve: From the first time I picked up the guitar I knew I wanted to do this for the rest of my life. Computers were in their infancy and MIDI had just come out so I was fascinated with the potential. I majored in music in college and during and after that worked in studios and was fortunate enough to learn a metric ton from Eric Valentine during his early years of running his own studio. The combination of all of that and working in the game industry sort of dovetailed into my forming my own company and doing this full time.

Eminence: Over the last several years you’ve been heavily involved in the wildly popular Guitar Hero video game series, writing nearly 100 tracks for gamers to play along with. Was it a conscious decision to get into the video game industry, or did it come about by accident?

Steve: It was definitely a conscious decision, but with a little push to get rolling. I’ve been involved in the tech and video game business since 1993 but in 2005 I was laid off when the company sold off their assets. It was at that point I decided to go full time in the freelance direction rather than do some work on the side with yet another job that wasn’t fulfilling. In 2007 I met up with the Guitar Hero guys just as they were getting close to the end of Guitar Hero 3 development. It turned out to be a great relationship and that game put me on the map. In all I worked on 8 games with Activision/Neversoft until they put it on hiatus earlier this year.

Eminence: Now that Guitar Hero is on hiatus, what’s keeping you busy?

Steve: It’s been a combination of music for television, video games and film trailers. Lately I’ve been doing re-records of classic dance tracks for Just Dance 3 (Ubisoft) as well as a lot of heavy guitar music for TV licensing. I find it ironic that the majority of shows that use my music are the cooking and home shows. HGTV and Food Network seem to use my music the most outside of sports shows. Who would have thought cooking and heavy guitars would pair up?!

Eminence: You obviously record a lot of guitar tracks, each with it’s own unique tonality. How important is the guitar speaker on each project? Do you change speakers to alter tonality?

Steve: The speaker is the final voice of the amplifier and crucial to the tone. I have 6 different cabs right now ranging from 4×12’s to 2×12’s to 1×12’s. Recently I picked up an amazing amp selector that lets me plug in 8 different heads and 8 different cabs. Then with a selection knob for amp and speaker I can choose which head routes to which cabinet. On the fly I can play the amp and switch through the various speakers to find the exact tone I’m looking for. Being able to do this has radically changed the way I record. It’s a dream setup.

Eminence: What would you list as the five most important things to achieving great guitar tone for recording.

Steve: Great question! Here are my five:

1. Back off on the gain. When you think you’ve got enough gain on the amp, back it down until it’s just about uncomfortable. The tones with less gain most always sound bigger than the super-distorted ones, which end up collapsing in the mix

2. Match the amp to the speaker. With the amount of options available there is no reason you have to settle on just one speaker. I like to load my 4×12’s with 4 different speakers and then choose the one I feel fits best in the track, then mic it up. It sounds a little weird in the room but is ultra-flexible for recording. My current favorite cab has a Texas Heat, Swamp Thang, Man-O-War and a Red Fang in it.

3. Matching guitar to amp. It probably sounds obvious but for every track you need the right combination of guitar and amp. Whereas a single coil guitar with a Tweed style amp might be right for one track, a humbucker with a Tweed might be perfect for another. How it sounds in the room also helps to determine how it will sound in the track.

4. The little things. Strings, pick type and cables. All of these little things add up, especially under the microscope of a recording. If I want more zing in my tone I’ll switch to a lighter string gauge. Alternatively the heavier strings don’t “give” as much and contribute to a more muscular tone. It’s a choice that makes a difference in the sound AND performance.

5. The part. More important than 1-4 is the actual part performed on the recording. I’m amazed at how simplifying a performance or adjusting it to fit around a vocal makes the recording sound so much better. Time and time again the coolest parts can overshadow the point of the song and sound busy. Although a lot of people laugh at KISS for being a simple band, Paul and Ace were masters of creating monster riffs out of simple parts and different voicings of chords played together. Malcolm and Angus are another duo that comes to mind. It’s the space in between the notes that makes the sound so big, and it translates to the recording very well. All about the part.

Eminence: There’s been a lot of discussion about mic’ing a guitar amp/cabinet for recording. What’s your method?

Steve: I don’t have one set method for mic’ing but I tend to like a 57 straight on the center of the cone with an additional mic about 3 feet back to capture the room. Of course that depends on the track and what it needs but a little bit of room makes the speakers come alive. It really depends but when is the last time you jammed your ear right up on a speaker to listen to it? Like drums the room has a lot to do with the sound of the amp although for modern production the immediacy of a close mic is almost just a given. Lately I’ve been using a Royer 101 in tandem with the 57 and getting amazing results. It’s no secret but it is a great sound.

Eminence: Do you prefer open back or closed back cabinets, and why?

Steve: 95% of the time I prefer a closed back design. It’s probably just because I came up on the Marshall side rather than the Fender side. That said, more recently I’ve been playing a few open back cabs and have enjoyed their open sound. It’s all-enveloping rather than directional. I won’t call it 3D because that term shouldn’t exist…3D is one of those terms people throw around a lot but hardly makes sense.

Eminence: Do you prefer high or low SPL speakers, and why?

Steve: Both. Low SPL speakers are great for adding more grind to non-master volume amps to my ears. The flip side is master volume amps and how they like a good, high headroom speaker. They’re also great for cleans when you don’t want any give or breakup. Because I do so many styles of music there is no one particular choice, it’s all of them. Oh yeah, and I never use the term “cone cry”…not acceptable!

Eminence: How do you break your speakers in?

Steve: The old fashioned way. Beat em up with old Marshalls full-up. There’s no better way to break a speaker or a sneaker in than use, and my speakers get a workout!

Eminence: What made you decide to work with Eminence for your loudspeakers?

Steve: For me it was for the quality, Made-In-USA manufacturing and variety. But in the end it came down to relationships. Eminence is good people that are so dedicated to their customers and artists I immediately felt like one of the family. And that is worth its weight in “insert your favorite precious metal here”.

Eminence: What Eminence speakers do you use the most, and why?

Steve: So many! I’m a huge fan of the Reignmaker because not only is it a great sounding speaker, I can ditch the external attenuator and just turn the volume down on the speaker (never thought I’d see that day). Aside from that I regularly use Texas Heat and Swamp Thangs together as well as the Man-O-War.

Eminence: What’s next on the horizon for Steve Ouimette?

Steve: “I just signed on with Rappapd Media Group for film and TV representation so there are new projects in the works right now. In January I will be speaking at NAMM on a panel on sound designer which came about through my virtual instrument “Cinematic Guitars” from Sample Logic. And finally, along with the ongoing work on game soundtracks you’ll still see my articles and reviews as a writer for Premier Guitar Magazine. 2012 is shaping up to be a great year.”

Pick Your Sound.

 

As a direct response to his popularity with guitar fans worldwide Steve released “Epic”, a solo CD and companion DVD on Sumthing Else Music Works in the Fall of 2010. Critically heralded as a dynamic and diverse album featuring an eclectic mix of guitar-laden virtuosity and wide reaching styles, “Epic” shines new light on guitar instrumental music by fusing cinematic drama and intensity.

Steve is a regular contributor for Premier Guitar Magazine where he writes a monthly column, “Hey, You Can’t Do That!”, as well as gear reviews and feature articles.

Learn more about Steve at his website, www.SteveOuimette.com

Photo courtesy CovingtonShoots.com

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Jon Bloomer at GuitarNoize.com Demos a Texas Heat™ and Swamp Thang™

September 1,2011

Jon Bloomer knows a thing or two when it comes to guitar tone. He’s been playing since he was 12 years old, and since 2007 he’s been the brains behind GuitarNoize.com, a website that is loaded with everything a guitar enthusiast loves. This video features one of our most popular combinations of classic American tones, the Texas Heat™ and Swamp Thang™, both from our Patriot Series of guitar speakers.

“In this demo I loaded an Eminence Texas Heat and an Eminence Swamp Thang speaker into my Blackstar HTV-212 Cab and setup a single Audix i5 on each speaker. There are two rhythm tracks panned 50% left and right (Texas Heat on the left) and then 2 lead tracks which alternate and I have made it clear in the video which speaker is being used when by switching the title and speaker graphic. ”

“The Texas Heat is a little darker than the Swamp Thang and creates some great Eric Johnson style lead tones. The Swamp Thang breaks up nicely when you play hard and has a little more presence and as you can hear combined they are a perfect match for a great rhythm tone.” – Jon Bloomer | GuitarNoize.com

Check out more of Jon’s great posts at GuitarNoize.com

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Sealed vs. Ported Enclosures

Tech Talk With Big Tony June 23,2011

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.

Sealed Enclosures

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

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.

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Eminence Speaker LLC Offers the Ultimate Loudspeaker Protection to Pro Audio and MI Markets

June 6,2011

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 protection circuitD-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 josh.martin@eminence.com for more information.

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