Starting a business involves planning, making key financial decisions, and completing a series of legal activities. Scroll down to learn about each step.

1. Conduct market research

Market research will tell you if there’s an opportunity to turn your idea into a successful business. It’s a way to gather information about potential customers and businesses already operating in your area. Use that information to find a competitive advantage for your business.

2. Write your business plan

Your business plan is the foundation of your business. It’s a roadmap for how to structure, run, and grow your new business. You’ll use it to convince people that working with you — or investing in your company — is a smart choice.

3. Fund your business

Your business plan will help you figure out how much money you’ll need to start your business. If you don’t have that amount on hand, you’ll need to either raise or borrow the capital. Fortunately, there are more ways than ever to find the capital you need.

4. Pick your business location

Your business location is one of the most important decisions you’ll make. Whether you’re setting up a brick-and-mortar business or launching an online store, the choices you make could affect your taxes, legal requirements, and revenue.

5. Choose a business structure

The legal structure you choose for your business will impact your business registration requirements, how much you pay in taxes, and your personal liability.

6. Choose your business name

It’s not easy to pick the perfect name. You’ll want one that reflects your brand and captures your spirit. You’ll also want to make sure your business name isn’t already being used by someone else.

7. Register your business

Once you’ve picked the perfect business name, it’s time to make it legal and protect your brand. If you’re doing business under a name different than your own, you’ll need to register with the federal government, and maybe your state government, too.

8. Get federal and state tax IDs

You’ll use your employer identification number (EIN) for important steps to start and grow your business, like opening a bank account and paying taxes. It’s like a social security number for your business. Some — but not all — states require you to get a tax ID as well

9. Apply for licenses and permits

The post How to start a business appeared first on Ghosi.in.

From 2010 to 2015, the US voice coil winding industry was slowly and painfully decimated. The bulk of the speaker assembly industry moved to Asia or to Mexico, but the last few domestic coil winders hung on as they offered extremely high power coils, high-aspect-ratio flat wire coils, or other unique attributes. Eventually, the top coil winders in Asia acquired most of these capabilities. Today, only Precision Econowind remains in the US, both to wind and supply its high-performance voice coils. The company also serves as the agent for Poyun’s off-shore voice coils. In any case, we have not published a tutorial on coil winding in Voice Coil magazine in five years, so here we go.

Voice Coil Basic

The typical speaker voice coil has less than a half-dozen components: the bobbin, the wire, the collar, adhesives, and the lead-out wire. The voice coil starts out with a die-cut, pre-coated with adhesive blank, onto which is the voice coil wire is wound. The form factor of the bobbin blank will depend on many factors. Of course, the bobbin’s diameter is dependent on the voice coil gap diameter. The clearance specified from the pole piece to bobbin is usually less than the clearance specified from the coil’s outer diameter to the top plate. Pole piece to bobbin rubs are less damaging than coil insulation to top plate rubs and accommodate the coefficients of coil’s expansion due to heating.

The height of the bobbin depends on numerous factors including:
• The voice coil winding height
• The distance between the top of the voice coil stack to the spider. The distance between the top of the coil and the spider provides the clearance needed to prevent the spider from contacting the basket/top plate on downward strokes. Typically, this dimension is actually the byproduct of the particular cone and speaker basket selected.
• The distance the bobbin extends beyond the neck joint and cone apex attach. If the bobbin extends too high, then a larger or deeper dust cap must be used.

Winding the voice coil entails placing the blank onto an arbor, forming it into a cylindrical bobbin, and winding wire onto the form. As the coil is wound onto the bobbin, the insulation coating (and the thermoset adhesive coating on the blank) is activated with MEK, alcohol/acetone or another solvent system.

Alternatively, wet winding wire techniques are used, usually for very high power voice coils. In this case, the adhesive is applied to the insulated, non-adhesive coated magnet wire as part of the winding operation. The entire voice coil assembly is then cured. Traditionally, the coil is baked to snap-over the thermosetting glue forming a molecular cross-linked bond. Baking time is going to be longer than the stated adhesive cure time and will depend on the American Wire Gauge (AWG) number, which might range from #35 to #28, and the number of layers, from single-layer flat wire to four layers (or even eight layers).

The typical speaker voice coil has less than a half-dozen components: the bobbin, the wire, the collar, adhesives, and the lead-out wire. The voice coil starts out with a die-cut, pre-coated with adhesive blank, onto which is the voice coil wire is wound. The form factor of the bobbin blank will depend on many factors. Of course, the bobbin’s diameter is dependent on the voice coil gap diameter. The clearance specified from the pole piece to bobbin is usually less than the clearance specified from the coil’s outer diameter to the top plate. Pole piece to bobbin rubs are less damaging than coil insulation to top plate rubs and accommodate the coefficients of coil’s expansion due to heating.

The height of the bobbin depends on numerous factors including:
• The voice coil winding height
• The distance between the top of the voice coil stack to the spider. The distance between the top of the coil and the spider provides the clearance needed to prevent the spider from contacting the basket/top plate on downward strokes. Typically, this dimension is actually the byproduct of the particular cone and speaker basket selected.
• The distance the bobbin extends beyond the neck joint and cone apex attach. If the bobbin extends too high, then a larger or deeper dust cap must be used.

Winding the voice coil entails placing the blank onto an arbor, forming it into a cylindrical bobbin, and winding wire onto the form. As the coil is wound onto the bobbin, the insulation coating (and the thermoset adhesive coating on the blank) is activated with MEK, alcohol/acetone or another solvent system.

Alternatively, wet winding wire techniques are used, usually for very high power voice coils. In this case, the adhesive is applied to the insulated, non-adhesive coated magnet wire as part of the winding operation. The entire voice coil assembly is then cured. Traditionally, the coil is baked to snap-over the thermosetting glue forming a molecular cross-linked bond. Baking time is going to be longer than the stated adhesive cure time and will depend on the American Wire Gauge (AWG) number, which might range from #35 to #28, and the number of layers, from single-layer flat wire to four layers (or even eight layers).

Voice coil consideration

Specification Blanks — Let’s drill deeper on the bobbin substrate materials, which starts off with the some considerations for the required/desired strength, mechanical and electrical properties, and temperature tolerance. The outside face of the blank is coated with a thin film of B-staged thermoset adhesive. Blanks are often purchased pre-coated from a “converter,” which is a firm that both coats and slits, as well as stocks and distributes voice coil winding materials (some converters are listed in this month’s directory).

Coating and Converting — Coating thickness is a factor in total film thickness, but should be separately specified from the film substrate itself. For bobbin thickness, 1 mil or 2 mil bobbins are used where mass/thickness are critical (e.g., in tweeters), and 2 mil and 3 mil is ideal for standard automotive loudspeakers. The 3 mil bobbin thickness is popular for many consumer audio applications (e.g., soundbars and smart speakers), while 5 mil is used where wall strength is critical (e.g., higher output speakers, especially woofers).

Bobbin Configurations — Bobbins might have spiral or butt joints. In the latter case, there is a slit or gap in that joint. Depending on the voice coil diameter, the butt gap is typically 1/64” to 1/32” wide. This gap will expand during high-temperature operation of the voice coil. Spiral bobbins have been used to improve the roundness of bobbins where tight voice coil gaps are required.

At first glance, non-electrically conductive bobbin substrates do not require a gap as overlapping will not create a shorted turn. Shorted turns with electrically conductive materials result in inductive effects, such as high eddy currents, higher distortion, rocking of the coil, and heating. There are many superior speakers with aluminum bobbins, with the design using eddy-current canceling techniques (copper cap, shorting ring) to avoid distortion while increasing damping. Nevertheless, most bobbins are split to accommodate thermal expansion of the voice coil.

Bobbin Venting — Some speaker engineers use holes punched into the bobbin between the top of the voice coil stack and the neck joint. Primarily, this technique is used to improve cooling. Air cavity pressure buildup may be reduced behind the dust cap with this form of bobbin venting. Other positive effects are mass reduction and dampening torsional bobbin resonances. One not so attractive effect is the nasty turbulence “whistling” that can result if the air velocity is too great through the vents or if the vents become partially blocked on large excursions. If the vents are too large, then the structural integrity of the bobbin could be compromised and buckling may result.

Collars — A collar is one or more turns of a band of material located between the coil stack and the neck joint. Often, the collar extends into the neck joint. Primarily, the collar is used to properly dress the lead-out wires from the coil, but lead-out wires may also be glued directly to the bobbin.

Secondary features of collars are to enhance adhesion and maintain roundness. Additional purposes may include added bobbin wall strength, temperature insulation between the bobbin and the cone, and as a correction factor for fitting bobbins that are slightly too small for a stock cone I.D.

Thermal Considerations — Aluminum bobbins are popular due to high thermal transfer but might result in excessive heat to the neck joint, not only due to their thermal conductivity, but also due to self-heating effects from the eddy currents. If high heat is anticipated at the neck joint, this may require compromises in the selection of adhesives.

Additionally, the eddy currents are not uniform along the width of the bobbin due to divergence of the induced current at each end of the sheet. This results in a tipping or canting force induced on the voice coil that is proportional to the cone velocity.

Thermoset polyimides are significantly lower in mass than aluminum, and as they are not electrically conductive, will not short out the voice coil in case of insulation failure between the coil and the bobbin. DuPont Kapton, UBE Ulpex and Kaneka Apical are the leading suppliers of thermoset polyimides (PI) and not to be confused with thermoplastic PI, which is often supplied by Chinese voice coil vendors.

The thermoplastic films go soft at higher temperatures and can result in “coil shucking” and bobbin deformation at much lower power levels than thermoset PI. Fiberglass and composite materials have also been used on bobbins for high-power woofers and sub-woofers with good results.

Wire Consideration

Magnet Wire — Magnet wire is available in a wide range of sizes, cross-sectional profiles, and wire insulation coatings. The insulation layer is called the base coat and is available with an adhesive bond, which is the top or outer bond coat. Magnet wire is often pre-coated (green = dry but not cured) with an adhesive that is reactivated during winding (typically with 10 parts MEK or alcohol to 1 part adhesive). Alternatively, the wire can be wet-wound, with the top-coat adhesive applied to the non-adhesive coated wire during the winding operation.

The wire gauge, often referred to by its AWG designation, is selected by a number of factors, including desired DC resistance, mass considerations, (current) power handing, and magnetic system considerations. A high-power subwoofer might use a gauge as heavy as #28 AWG, while a super tweeter might use a wire gauge as fine as #38 AWG. Fine wire is considered 34 AWG to 44 AWG. Note that with AWG, #32 AWG has twice the diameter of #38 AWG, #26 AWG is twice the diameter of #32 AWG, and so on. Every six sizes increases the current capacity by a factor of 4, and every three sizes increases the capacity by a factor of 2. Conductor material considerations aside, strength is directly proportional to the cross-sectional area of the wire.

Copper wire is most commonly used for speakers, although aluminum and copper-clad aluminum wire (CCAW) are also used. Copper is more conductive than aluminum and substitution of aluminum for copper requires a larger diameter wire for the same conductivity. Copper offers superior strength and is much easier to solder to than aluminum. New alloys are in development that will offer advantages over existing conductors.

Wire Joining — Joining lead-out wire to aluminum voice coils requires special fluxes or mechanical (crimp) connection techniques. Aluminum offers lower mass with greater conductivity per unit weight than copper. Aluminum wire is vulnerable to work with—hardening when used at elevated operating temperatures, resulting in brittleness and wire failure. Furthermore, aluminum expands over one-third more than copper when subjected to the same temperatures. CCAW offers much of the benefits of both materials, but is still not as robust as copper wire.

Round vs. Flat Wire — Round wire is most commonly used in voice coils. In high-performance speakers, wire that has been flattened and wound-on-edge is sometimes used. Benefits include greater wire density in the gap, and a single layer of flat wire has less inductance than two or more layers of round wire. It is far simpler to buy flat wire coils than to produce them. Flat wire requires that the round wire be flattened (usually by rollers) and spooled.

Load-Out Wire — Load-out wire types vary depending on the speaker. There are many choices of braided wire, with variations in gauge or fabric strands woven in with the wire. Alternatively, in high-powered tweeters and compression drivers, flat conductor strips are sometimes used with phosphor bronze or Beryllium alloy. Various wire dress options can be selected for the lead-out wires, including wire spacing and the use of a collar between the coil stack and the neck joint.
 

The post Voice coil : A Tutorial appeared first on Ghosi.in.

How Speakers are Built

The first electronic loudspeaker designs were introduced in the 1920″s, and while there have been many improvements in component materials over the decades, not much has changed in the basic functionality of a loudspeaker: a permanent magnet interacts with an electromagnet (voice coil) to move a cone back and forth to produce sound waves. Founded in 1966, Eminence has been a leading supplier of loudspeakers for professional audio, musical instrument, car audio and home hi-fi applications to many of the world”s most recognized brands. While our own components and manufacturing processes have evolved, the way we assemble speakers today doesn’t differ that much from when we started. Here”s how we do it.

Voice Coils

At the heart of every loudspeaker is the electromagnet, more commonly known as the voice coil, which uses an electric current to produce its magnetic field. The first step in making a voice coil is the winding process. A Kapton, Nomex, paper, or fiberglass former material is wrapped around a steel mandrel, which is used to keep it round during this process. These former materials are chosen for their thermal power handling and sonic contributions. Next, copper or copper-clad aluminum wire is wound to specific lengths according to the design. The coil is then baked to cure the adhesive used for coating the wire. An assurance bead of glue is added at the top and bottom of the winding. As an added quality assurance measure, we double-bake our coils at this point. For added strength we often add beryllium or copper strips to the coil. Then a paper collar is wrapped around the coil to protect the wire that goes from the winding to the tensile leads. These leads are then spliced onto each end of the winding. We then check the DC resistance and overall quality of each coil. Fun fact: Eminence makes 95% of our voice coils in-house.

Permanent Magnents

\
When the voice coil receives an electric current and produces a magnetic field, it is repelled by the permanent magnet fixed to the loudspeaker basket. These magnets come in various sizes and materials, but interestingly enough, they aren”t magnets at all until the loudspeaker assembly reaches the end of our production line. Eminence uses ferrite, lightweight neodymium, and alnico (a combination of aluminum, nickel, and cobalt) magnets. Fun fact: Eminence uses over 360,000 magnets each year.

Metal Parts

There are a few metal parts used in the construction of a loudspeaker: the basket, top plate, back plate, and core. At Eminence we use a variety of loudspeaker basket types and sizes. Our cast-aluminum chassis range from 5″ to 18″ in diameter, and our stamped steel models range from 6.5″ to 15″. We also have a variety of powdered metal and steel cores, in both vented and solid construction, and range in size from 1″ to over 4″. The top and back plates are stamped from rolls of steel in our Press Shop. The top plate is either welded or staked to the basket, and the back plate will have a round core welded or staked to the center of it. These two plates will eventually sandwich the permanent magnet. Once our metal parts are assembled, they are then sent through our in-house e-coat paint process. A uniform coating of cationic epoxy paint is applied over the entire surface of the metal parts to a controlled thickness of less than 0.001″. Fun fact: Eminence purchases over 1,160 tons of American made steel each year, the majority of it from Steel Technologies right across the street from our factory.

Soft parts

The soft parts of a loudspeaker are the cone, dust cap, spider, and surround. Our cones come in many different sizes and the bodies are typically made of paper. The surrounds can be made of paper, cloth, Santoprene, rubber, or foam. The spider and the surround make up the mechanical suspension, which brings the cone back to its original resting position. Fun fact: Eminence purchases over 310,000 cones each year from suppliers in the USA, UK, and Malaysia

Final Assembly

The first step of the final assembly process is to attach a terminal board to the painted basket/top plate assembly using either glue or rivets. Next a rear gasket is applied to the basket to create a seal with the enclosure if the speaker is to be front-mounted. Next, the magnet and painted back plate/core assembly is glued to the top plate using a centering gauge to ensure a uniform magnetic gap, the narrow space between the permanent magnet and the metal core where the voice coil sits. A bead of glue is applied to the flange of the basket to attach the cone surround. A vacuum is then used to remove any debris from the magnetic gap. A Mylar gauge is then inserted into the voice coil to help the technician set the exact coil height for the given loudspeaker design. A bead of glue is then added around the coil to adhere it to the spider.

The next step is to apply a bead of glue to the bottom of the spider, and then place it over the voice coil and attach it to the basket. At this point the voice coil is glued to the spider, which is glued to the basket. The cone is then inserted into the basket, and is pressed into the bead of glue that was applied earlier. Another bead of glue is then applied to attach the cone to the voice coil. The lead wires from the coil are fed through the two small holes that were pre-drilled through the cone and then through the terminals. The Mylar gauge is then removed from the voice coil and the exposed lead wires are covered, or dressed” with a rubber cement for added strength.

An edge treatment is used to seal porous cloth surrounds, as well as for sonic and performance enhancements. A final bead of glue is applied to the cone to attach the dust cap, which is used to keep dust and debris from getting inside the magnetic gap. Once the dust cap is in place, the speaker is then sent through our C-core magnetizer, using a field strength of 20 tesla meters to create the magnet. A front gasket is then added to the basket to create a seal with the enclosure if the speaker is to be rear mounted. The tensile leads are crimped to the terminals and the excess wire is trimmed. A small bead of glue is applied to each terminal to fix the lead wires in place.

The speaker is fully assembled at this point. A conveyer belt slowly moves the speakers through an oven to cure the glue, and then a technician at the end of the line sweeps the speaker with an audio signal. This is to ensure the final product is working properly and has no visible or audible defects.

Fun fact: 100% of the speakers manufactured in the Eminence factory are listened to by a person.

Cosmetic enhancements are applied last, including a back plate label and a rubber magnet boot to provide a clean and professional look. If the product is going to an OEM customer, it is typically assembled on a pallet, shrink wrapped and staged in our shipping department. Otherwise, the speaker is sent to our packing line to be boxed and stored in our warehouse for distribution to virtually any destination in the world.

The post Speakers appeared first on Ghosi.in.

A voice coil (consisting of a former, collar, and winding) is the coil of wire attached to the apex of a loudspeaker cone. It provides the motive force to the cone by the reaction of a magnetic field to the current passing through it. The term is also used for voice coil linear motors, such as those used to move the heads inside hard disk drives, which produce a larger force and move a longer distance but work on the same principle.

Design considerations

Because the moving parts of the speaker must be of low mass (to accurately reproduce high-frequency sounds without being damped too much by inertia), voice coils are usually made as light weight as possible, making them delicate. Passing too much current through the coil can cause it to overheat (see ohmic heating). Voice coils wound with flattened wire, called ribbon-wire, provide a higher packing density in the magnetic gap than coils with round wire. Some coils are made with surface-sealed bobbin and collar materials so they may be immersed in a ferrofluid which assists in cooling the coil, by conducting heat away from the coil and into the magnet structure. Excessive input power at low frequencies can cause the coil to move beyond its normal limits, causing distortion and possibly mechanical damage.

Power handling is related to the heat resistance of the wire insulation, adhesive, and bobbin material, and may be influenced by the coil’s position within the magnetic gap. The majority of loudspeakers use ‘overhung’ voice coils, with windings that are taller than the height of the magnetic gap. In this topology, a portion of the coil remains within the gap at all times. The power handling is limited by the amount of heat that can be tolerated, and the amount that can be removed from the voice coil. Some magnet designs include aluminium heat-sink rings above and below the magnet gap, to improve conduction cooling, significantly improving power handling. If all other conditions remain constant, the area of the voice coil windings is proportional to the power handling of the coil. Thus a 100 mm diameter voice coil, with a 12 mm winding height has similar power handling to a 50 mm diameter voice coil with a 24 mm winding height.

The actual wire employed in voice coil winding is almost always copper, with an electrical insulation coating, and in some cases, an adhesive overcoat. Copper wire provides an easily manufactured, general purpose voice coil, at a reasonable cost. Where maximum sensitivity or extended high frequency response is required from a loudspeaker, aluminium wire may be substituted, to reduce the moving mass of the coil. While rather delicate in a manufacturing environment, aluminium wire has about one third of the mass of the equivalent gauge of copper wire, and has about two-thirds of the electrical conductivity. Copper-clad aluminium wire is occasionally used, allowing easier winding, along with a useful reduction in coil mass compared to copper.

flat wire may be used, providing an insulating oxide layer more resistant to dielectric breakdown than enamel coatings on other voice coil wire. This creates lightweight, low-inductance voice coils, ideally suited to use in small, extended range speakers. The principal power limitation on such coils is the thermal softening point of the adhesives which bond the wire to the bobbin, or the bobbin to the spider and coil.

Voice coils can be used for applications other than loudspeakers, where time force linearity and long strokes are needed. Some environments like vacuum or space require specific attention during conception, in order to evacuate coil losses. Several specific methods can be used to facilitate thermal drain.

Overhung and underhung coil

The image above shows two ways in which the voice coil is immersed in the magnetic field. The most common method is the overhung design where the height of the voice coil is greater than the magnetic gap’s height. The underhung design which is used mostly in high-end speakers has the coil’s height smaller than the gap’s. The differences, advantages and disadvantages of both methods are listed below.

Both topologies attempt the same goal: linear force acting on the coil, for a driver that reproduces the applied signal faithfully.

Coil Size Matter

A smaller speaker like a 6″ speaker, often has a smaller voice coil than a larger speaker like the 8” version of the same speaker. Why does that matter? Well, the larger you make the voice coil, the more power it can handle—but at the same time, it also generates more heat. Smaller coils can be a little more resonant, but larger coils tend to have better control.

Some speakers have to have larger coils. Subwoofers like the MTX 12” 150-Watt Vented Powered Subwoofer need a larger magnetic gap, so they have bigger coils and commensurately bigger heat and power. As the gap gets bigger, so too must the magnet. A tweeter, which only produces high frequencies, can get away with a much smaller coil.

The Sound of Experience

Having a well-engineered coil helps your speaker’s power handling, sound reproduction, and long-term durability. MTX has been doing this for over 40 years—since 1971!—and all that experience has gone into making speakers that are well-engineered, solidly-built and excellent value. That expertise means something.

We can help set you up with the perfect speaker for your customers. Check out the rest of Petra.com to see the huge variety of MTX speakers we carry, from car audio to in-wall audio to home theater. See the newest products and help your customers hear the difference with Petra and MTX.

The post Blog appeared first on Ghosi.in.

The post Hello world! appeared first on Ghosi.in.