Full Technical Write-up of the Super-Neo-Woofer design

[Dwn4BassAlan]

So, I figured that it might be a helpful/useful idea if I gave a pretty detailed account of my research and design aspects of the Super Neo build that lots of you have seen. I want to make it clear to everyone what my thought process was throughout the build so that you can learn new things and answer any questions you might have.

Let's start off with the simple basics; if you already understand the concepts of a subwoofer, it's core engineering, and how it is built, then just skip down to the part of "WHAT I AM TRYING TO ACCOMPLISH", but if your a new comer or you just want to learn the fundamentals, read on.

-What is a subwoofer?

Well, it's basically a large speaker. What exactly is a speaker though? A speaker is an electroacoustic transducer that produces sound in response to an electrical audio signal input. The most common type of speaker uses a paper cone supporting a voice coil electromagnet acting within a magnetic field given from a permanent magnet.

So, a subwoofer is generally designed for the reproduction of low-pitched audio frequencies. The typical frequency range for a subwoofer is about 20–200 Hz.

-But, why does a subwoofer have to be so large?

Well, because the group of non-woofer speakers are designed to reproduce audible sound frequencies normally between 50Hz-20,000Hz it's built in such a way that it can keep up with the desired frequency, remember the Hz is the amount of completed (up and down) "pumps" a speaker does per second, and 20,000 pumps per second is pretty damn fast. There are many speaker sizes ranging from 1-inch tweeters to 6x9 -inch and so on... Tweeters are designed to play frequencies from 3500, 4500 or even 6000 Hz, all the way up to 20,000 Hertz. Midranges (3, 4 or 5 inches) play music from around 300, 500 Hz, to where the tweeters start in the upper level. Midbases (5, 6, 8 inches) play from around 50 Hz to 500 (and even 1000) Hz. A smaller speaker will reproduce higher frequencies better than a bigger one simply because of the lesser amount of mass that it is required to move, allowing it to more quickly and cleanly finish the shorter strokes. The wavelength of a 20,000 Hz signal is very small, so it would be impossible for a speaker the size of a subwoofer to effectively move it's heavy massive cone quickly enough to accurately reproduce the frequency. Though, the lower the frequency the larger the sound wave, and that explains why a 4"-6"inch speaker can't really put out bass since the lower the frequency, the more air mass that has to be moved by the cone of the speaker. This is what makes the subwoofer so perfect for bass, because just like the woofer can't do the speakers job, the speaker can't do the woofers job. Once the frequency gets low enough, the amount air that would have to be moved by the cone gets too be too much for the normal-cone-sized speaker to handle, it can't possibly push enough air far enough to make an audible low-end frequency that human ears could detect. So the woofers large area of cone combined with the ability to have high excursion due to extremely powerful magnetic motor force make it the perfect "tool for the job".

-So what do the various kinds of woofers do?

There are subwoofers of all kinds. Small, big, heavy, whatever. There's thousands and thousands of different woofer combinations and components that all have their own role to fulfill in reproducing the best sound, they employ new equipment, technology, motor structure, materials, coils, cones, suspensions, and baskets to try an keep improving them. They all focus on reproducing low-end bass frequencies. Though some are designed to do it more efficiently or more inventively than others. There are some woofers designed to maximize SPL (sound pressure levels) through huge burst of power at a more specific range of frequencies, these of which are not always intended to be used for daily usage on music. There are woofers designed to focus less on overall loudness and go for maximum SQ (sound quality) which is most accurately reproducing the audio signal by flattening the audio spectrum, or basically avoiding the woofer having a "peaky" response to certain frequencies. There are also many balanced woofers that will give you a combination of both, or are as "ln-between" as they can be to give the user the most inclusive options to fit their varying needs. There's no one woofer that is the best for everyone, and a bass system does NOT solely rely on the woofer, the power source and the enclosure play equally important parts.

-So what makes up the woofer motor?

Well, there are only a few ways to build the basic motor structure of a Subwoofer. At least only a few to keep it practical for most applications. The most common of which is a motor that uses strontium ferrite and iron oxide permanent magnets (usually called ceramic magnets, they're the dark/black magnets) because it is relatively cheap and easy to shape, it can also withstand very high temperatures before losing magnetic strength. Most subwoofer that use ceramic magnets uses 1 or more cylindrical rings that provide the static magnetic field the woofer requires, which are sandwiched between the base-plate and the top-plate of the motor. There is also a pole in the very middle of it all, which is connected to the base plate, that the voice coil will cover, but does not contact the pole. This pole acts as the inner part of the magnetic flux and with the top plate. The top-plate will usually act as the outer ring of the magnetic-flux (also called the gap) which is the space where the most of the magnetic field is forced into so the coil will be attracted and repelled from the magnetic poles once it is given changing electrical signals from the amp it will react in the presence of the magnetic field.

The other motor structure has the same basic design with the only difference being the permanent magnet material. This is what makes the difference between ceramic and neo woofers. Because Neodymium has one of the highest magnetic properties of any magnetic alloy, it is a very useful magnet source for subwoofers because it can produce much greater magnetic strength in a same-sized application than with any other type of magnet except for neo-demetrious iron proton (Ned) magnets :D. It also has an extremely high coercivity, meaning it will retain it's magnetic strength very well for years to come, even when constantly attracting or repelling. The only downside to Neodymium is it's lack of heat handling. Once Neodymium gets to 80*C it will lose a fraction of its magnetic strength, though it won't be completely drained until it reaches 310*C. But the worst thing about neodymium is it's price. So building a motor with neodymium allows you to pack in a much greater amount of magnetic strength with less magnetic material and a lighter-weight structure than with ceramic magnets, but it will certainly cost you a much greater amount.

In the past few years companies have ventured into designing their own subwoofers that employ the power of Neodymium, but many of them are so expensive that it is not practical for them to build it. But there are a few out there that don't have very large amount of Neo and are somewhat affordable and still have an amazing output.

-What I am trying to Accomplish? The overall goal.

I just want to build a badass neo woofer that has an absolutely ridiculous amount of power, hits the deepest lows, and looks good all while doing it.

-How am I going to do it?

Well a few thousand dollars worth of neodymium to start, then add in a few hundred dollars worth of other subwoofer parts and custom machined steel, followed by my will and determination, all backed by my knowledge and passion for science! Which is all fuled by the desire to just be loud I guess?

-Where am I going to start?

I'll lay the foundation with the motor structure, followed by the basket and cooling design, then the suspension, coil and cone.

-What will be the most challenging parts?

All of it basically, getting the magnets on was a total pain, assembling the top plate with the magnet structure will also be an unbelievable and ungodly difficult task, aligning the basket, voice coil, and suspension absolutely linearly will also be nearly impossible, so it should all be fun.

-Starting the build.

In my mind this is all about huge magnetic power, completely saturating the flux with an unnecessary yet very wanted amount of magnetic "poundability." So high grade neodymium and high magneticaly permeable A36 steel seemes like a good choice.

********************************************this is all I have time to write for now I'll keep updating it as I have time.*************************************