One of our most frequently asked tech support questions goes something like this: ”Hey I’ve got this old speaker and I’m pretty sure it’s an Eminence. Can you tell me what the power rating, impedance, and other specs are?” In this video, Eminence Speaker Tech Anthony “Big Tony” Lucas points out how to find the information on the speaker he will need in order to help you.
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Eminence offers coaxial woofers in 8”, 10”, and 12”, called the Beta-8CX, Beta-10CX and Beta-12CX, respectively. These woofers have a threaded pole-piece so that a screw-on, 1” exit high frequency driver can be attached to form a coaxial set up.
The woofer has a screen type dust cap, which allows the output of the high frequency driver to pass through the center. A small, 60 degree conical horn is attached to the top of the pole-piece beneath the dust cap. In my experience, it seems that our coaxial products are misunderstood and do not have enough exposure. In this article, I hope to raise awareness by sharing my own experiences and show how you can use them to create a great monitor or home hi-fi speaker.
Several years ago, I was finishing my basement to add more living space for my growing family. My wife gave me permission on nearly half of the basement addition to build a “man cave”/entertainment room. Since I work in engineering at Eminence Speaker (and my wife didn’t really think through the prospect of turning me loose on our basement ), I wanted to install an impressive, over-the-top sound system for home theater and general music purposes. I enlisted the help of Jerry McNutt, who is one of our design engineers, a passionate sound enthusiast, and a great box builder.
We decided to use the Beta-10CX, combined with the ASD:1001 for the front, rear, and center channels. I have a 5.1 system (Yeah, it’s been a while!). We decided on a 1.52 cubic foot enclosure, tuned to 60Hz for the front speakers and center channel.
We also added about a pound of pillow stuffing from Walmart for sound absorption. It was just left loose in the box. I mounted the rear speakers in the ceiling and used the space between the floor joists as an enclosure. We figured this would be sufficient, as there’s not much information sent to the rear channels, and they’re right over my head when I sit on our couch to watch a movie. This setup sounded pretty good with our stock crossover, PXB2:3K5, but we decided to make it even better. Jerry asked his crossover knowledgeable friend, Leo Frank, to assist. They used a spectrum analyzer to design an optimal crossover, which included padding for the tweeter. Eminence’s stock, board crossovers are nice for off-the-shelf products, but they are not optimized for any particular system and do not include padding for the tweeter. With the new crossovers, my speakers sounded incredible. They were dynamic, articulate, and focused, which are all great advantages for the application. The high SPL of the system was also a plus. I only had about 30 watts per channel of power available. I also incorporated a 4×15” subwoofer enclosure, but with hand-built, custom woofers (still Eminence, of course) in a rather odd cabinet design. I apologize, but the full details of the sub will not be part of this article.
DYI stage monitors
A few years later, my band wanted to get away from in-ear monitors and decided we needed some really good floor monitors. Again, our coaxials came to mind as a great possibility. We preferred a 12” woofer for this application, so I decided to use the Beta-12CX and the ASD:1001. I also wanted to try the same crossover that we used in my home theater project.
Jerry built a test box that was sealed and 1.21 cubic feet. I was skeptical that a sealed enclosure would produce enough bass. However, we tested it with a lot of different types of music, and surprisingly, it stayed very clear, tight, and punchy.
This was good news, because it kept the enclosures simple and in a smaller footprint than a ported enclosure would allow. We also stuffed the box full of fiberglass. This really cleaned up the mids. You could certainly use other acoustic absorption materials. I’m not sure exactly how much we used, and it’s basically a preference decision on how much to use. You need to add material until you’re satisfied with how it sounds. Jerry built 4 enclosures for me and we started using them in the band.
We were very satisfied with the sound quality and how much better we could hear ourselves. We were actually able to lower our stage volume because we could hear so much better. Stage volume was always a struggle before.
The results were so good that Jerry built more for himself and a close friend that does a lot of sound projects. We also started sharing the design with customers that we felt could benefit from it. A local church camp was building a new worship center on their campus and came to us for help on the sound. We shared the design and they built monitors for their stage. They also hired one of our customers that designs and builds high-end line arrays to install their front of house. As they were sound checking the install, our customer heard the monitors and asked us about them. He was very intrigued and measured their performance with a hand-held spectrum analyzer. He was blown away by the response curve and said they were nearly perfect without any EQ. He eventually adopted the design and added it to his own product line. Jerry and I convinced our sales and marketing to add the crossover to our line. It’s now called the PXB2:2K5CX.
Eminence Speaker LLC proudly introduces a 10" closed-back midrange version of their popular Beta 10A, the Beta 10CBMRA.
No other line of professional audio loudspeakers offers more value with performance than the American Standard series, and the Beta 10CBMRA is no exception. With its economical stamped steel, closed-back chassis, the Beta 10CBMRA offers versatility by eliminating the need for separate sub-enclosures. A usable frequency range of 300Hz to 4kHz combined with 200 watts continuous power handling makes the Beta 10CBMRA a perfect midrange driver for high-power pro audio cabinets, or high-power/high SPL car stereo applications.
"Using carefully selected components encompassed in a sealed basket, the Beta10CBMRA integrates effortlessly in to nearly any car or pro audio system." explains Matt Marcum, Design Engineer at Eminence. "With cabinet independence along with its optimized response and performance capabilities, system incorporation couldn’t be more simplified."
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.
From 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.
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!
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.