We carry speaker crossover parts from only the most respected manufacturers in the industry; Mills Resistors, Alpha/Goertz Foil Inductors, Reliable Capacitors AudioCap PPMF and PPMF-Theta, and MultiCap PPMFX. We also list the drivers that we use in our own designs. We provide these parts in our kits and completed speakers, or you can order them individually, below. Any of these make great upgrade components. See our Speaker Design system if you are attempting to determine which parts you need for a special speaker project; it can recommend the proper capacitors, inductors and resistors for your system.
If you wish to order only components, please place your order over the web site. If you are ordering many components, or have pre-sales questions, feel free to call us at 503-472-0688, 10 AM - 5 PM Pacific Time, Monday through Friday.
We use AudioCap metalized polypropylene (PPMF), Theta tin foil (PPT) and MultiCap (PPMFX) capacitors in our designs. We can special order other Reliable Capacitor models if desired, along with models from Solen and Erse as well.
If you don't see the exact value you need, order other values that add up to the needed value, then wire them in parallel. For example, if we need a 4μF capacitor, we can use a 1 and a 3, or two 2μF ones. If we need a 29μF cap, we'll use a 20, an 8 and a 1 (or one 30 and just call it good enough, depending on the desired precision).
Alpha foil inductors are considered among the best in the industry. We carry and use them in the 16g variety, which readily handles 300+ Watts. We can special order heavier gauge Alpha coils if you wish, or wire wound coils from Solen and Erse. Feel free to order using this form:
Ideal audio resistors will have little or no impedance or capacitance. We carry the highly-regarded Mills resistors in a wide array of values, 5, 10 and 12 Watt ratings, 5% tolerance. We can also special order resistors from Solen, Erse and Caddock. Please use this form to order resistors:
We carry a very limited set of drivers -- the ones we use in our own stock designs. But we can acquire others from manufacturer-approved distributors for use in finished speakers and kits. However, driver pricing is very competitive; if you need only drivers, you will do best to do some Internet shopping.
In addition to passive electrical components, we also carry:
Why do the components cost so much? I can get mid-level brand X capacitor/inductor/resistor for half as much elsewhere.
We carry circuitry components only from the most respected companies in the industry; Mills, Alpha, Reliable, etc. These components simply cost more, but if you are taking the time and effort to make top-quality speakers, we think it is worth it to spend a little extra to get the best possible sound. (Besides, even if you use our design system, there is no requirement to purchase your components here from us.) We don't inflate the prices, but we do put a lot of time and effort into making it as easy as possible to order what you need and get the right item on the first try. For these and other reasons, these parts cost a little more than the competition.
Which is better, air or iron core inductors, round wire or foil, and what gauge wire?
For high-fidelity audio applications, the general consensus is that air core coils carrying higher frequencies (~5000Hz+) introduce less distortion than metal core coils. But at lower frequencies it is a matter of some dispute. For the higher inductance values needed at low frequencies, metal core coils have the an advantage of smaller size and lower resistance (and therefore better power handling). The choice of foil or wire coils is also a matter of debate. Some argue that foil coils, like air core coils, introduce less distortion than round wire coils. It isn't clear, however, that this is true when comparing a foil coil to an "equivalent," high quality well-made wire coil. Bigger is not always better (or necessary): All other things being equal, coils with thicker conductor will have less resistance, more power carrying capabilities, more weight, more expense and larger size. Even an 18 gauge coil, well made, handles 300 W, many times the average power rating needed for almost any home system (and 14g can handle as much as 800W!). However, it will have roughly twice the DC resistance of a 14 gauge coil with the same inductance. So if circuit resistance is an issue, the choices are heavier wire (or a metal core).
Okay, how about resistors?
Specialized non-inductive audio resistors have very little inductance relative to their more common cousins. The less inductance, the more 'true' the audio signal will be to the original. Some audio resistors also need to burn off a significant amount of power, usually resistors used in woofer circuits. For these, we generally recommend 10-12W power ratings. Almost all other audio crossover resistors need not be more than 5W except in very unusual circumstances. This site analyzes the power levels likely to go through your crossover and recommends power ratings accordingly. There is no harm in picking a resistor with a power rating greater than is needed, but don't pick one that is smaller unless you have backups (or a fire-extinguisher) handy.
What about speaker cabling and internal hookup wiring
There probably isn't a more contentious subject in speaker making. There are about as many opinions on this as there are audio freaks, but they fall into two general camps: Only the most expensive exotic cables will do, or, just pick some good, heavy wire. Everyone agrees that corroded, faulty wire is bad. Beyond that, the jury is still out (and probably will be in perpetuity).
Capacitors: What style should I use?
Like questions about enclosure material, drivers, inductor and resistor design, the capacitor design and manufacturer is a matter of debate. The general consensus is that, for most applications, metalized polypropylene capacitors, if well made, are excellent for higher capacitance values and lower frequencies, and (more expensive) film and foil capacitors for higher frequencies and lower capacitances. Electrolytics are generally discouraged, but better quality bipolars are sometimes used in lower-end filters or when a very high capacitance is necessary, as in a subwoofer; a $10 bipolar electrolytic is fine for a subwoofer low-pass filter.
How close should my component values be?
Capacitors, resistors and inductors can be custom ordered and made to incredibly-tight tolerances, but for a price (usually a very high one). For example, we can custom order individual custom resistors from Caddock, but they cost as much as $50 each. Within 5% is usually fine. If your real value is off by 10% from the ideal, it might cause problems, especially if this is the case for multiple components. We purchase several of the same item at a time and hand measure and mark them for our use. Sometimes you have to combine two or even three components in series or parallel to get as close as desired to the ideal value, and it will still cost less than a custom part (e.g., 14μF capacitance requires three different AudioCaps PPMF placed in parallel, but this still costs less than a 14μF MultiCap -- more on this, below). It is unlikely that pursuit of 1% or better tolerance is actually useful because other, external factors will drastically affect the sound too.
Should I add fuses or breakers to the circuitry?
If your speakers are being connected to an amplifier capable of driving them beyond their long term peak power limit, then fuses or breakers should be added. Breakers cost less than new drivers.
I can't find a capacitor/inductor/resistor with the exact value I seek.
Perfect capacitors, inductors and resistors exist only in the imagination; in the real world they vary quite a bit. For example, capacitor and inductor actual values may be as much as 10% away from the labeled value. The resistors we carry are within 5%. Component values are also a function of the frequency, power and environment. You have four options:
Whatever you decide, we measure all of our components here. If you order from us, we will attempt to send you a part that is as close as possible to your desired value.
Aren't Mills Resistors available in 1% tolerance?
They are actually available in 5%, 1%, .5%, .25%, .1% and even tighter tolerances (for a price). We order the 5% tolerance because (1) it is usually close enough for most DIY projects, and (2) we hand measure, mark and select all of our pieces anyway. Custom designs often call for odd values just off of the typical E24 or integer values. For example, we order 7.5 ohms, an E24 series value. Due to its 5% spread, we can us pieces from the order for anything from 7.1 though 7.9, which covers the 7.3 we need for our normal designs. If we ordered 1% resistors, we'd have to order and inventory many more line items -- maybe four or five to cover the same 7.1 - 7.9 -- and each one would cost much more.
What about premade crossovers and crossover boards?
Use them if you like. We make our own crossovers from scratch. Well, we do buy the capacitors, resistors and most inductors. We cut a 1/4 inch thick piece of plywood to fit inside our enclosure, then layout and wire the crossover directly on the ply. The ply gets installed in the enclosure on top of thick foam, held in place by at least four screws.
Arpeggio Music and Sound, 805 NW Alder St, McMinnville, OR, USA. 97128
Telephone 503-472-0688; FAX 503-434-5803; Hours 10 AM - 5 PM Pacific Time, Monday through Friday
Visits by appointment only.