Friday, March 25, 2011

Balanced Armature vs. Dynamic Driver

How often have you stopped to wonder how those earphones that came with your MP3 Player actually produce the music that you hear?

If you've ever been to an Electronics store, you've probably stumbled across the Home Audio section. There you'll see a wide array of speakers, all with different sound signatures and purposes. However, the technology behind these speakers are mostly the same--it's how the speaker transducer is designed and tuned that makes the drastic difference.

There are two dominating speaker transducer designs on the market. The most popular speaker transducer is the Dynamic Driver (also less popularly known as the moving-coil driver). Pictured below, a Dynamic Driver uses a permanent magnet which is attached behind the diaphragm, along with a voice coil (usually made out of copper), to push air rapidly at different frequencies.

A Dynamic Driver Transducer, pictured above, is the most common transducer design used in speakers today.
Source: WikiMedia Commons

Not to get into the nitty gritty, the Dynamic Driver has been a very popular design because of its ability to produce the entire musical frequency range (~20 Hz - 18,000 KHz+) with relatively good success.

Have you ever seen a speaker design different from a Dynamic Driver? Well, I would like to introduce you to the Balanced Armature transducer (often abbreviated as a "BA driver") , pictured below.

A Balanced Armature Transducer, pictured above, does not require external air to produce sound. This makes a BA Transducer much easier to tune to specifications.
Source: WikiMedia Commons

A Balanced Armature is very small--and I mean tiny. These transducers are often used in hearing aids for people with difficulty hearing. More recently however, they have gained popularity in premium in-ear monitors for consumers and musicians alike. The Balanced Armature transducer uses the same concept of a permanent magnet and a voice coil as a dynamic driver, but the one major difference with the Balanced Armature transducer is that it does not require external air to operate. A Dynamic Driver, on the other hand, requires an air vent in order to sound marginally good.

The benefit of this design on the Balanced Armature is that it can be tuned very precisely since external air does not factor into the equation. This means that midrange and treble can be much more accurate and detailed than that of Dynamic Drivers. However, the Balanced Armature design also has a large drawback: since it does not require external air to work its best, it lacks a convincing low-end response (bass response). This is often alleviated by combining several Balanced Armatures together, and putting them on a single crossover.

The JH16 custom in-ear monitor (a 16 Balanced Armature transducer) pictured above next to the Sennheiser HD800 (a dynamic driver headphone). The JH16 in-ear monitor uses a passive triple crossover to redirect portions of the audio input to their respective Balanced Armatures.

What the crossover does is it splits the audio input into two or three (rarely more) frequency bands. This alleviates the problem significantly, as each Balanced Armature is now only responsible for handling a certain portion of the audio. A triple Balanced Armature in-ear monitor such as the EarSonics SM3 uses a single Bass Balanced Armature, single Midrange Balanced Armature, and single Treble Balanced Armature. This changes the response of the in-ear monitor significantly, and the bass response becomes much more realistic and natural.

After having heard Dynamic Drivers for many years, I tried a Balanced Armature in-ear monitor (the Shure SCL4), four years ago. The midrange was impressive, but the in-ear monitor lacked bass and a realistic treble. I then upgraded back to a Dynamic Driver (the Sennheiser IE8), which made me miss the detail retrieval of the Shure SCL4.

It was then that I knew that something about the Balanced Armature transducer made music sound all the more better. So I upgraded again to a Triple Balanced Armature in-ear monitor, the EarSonics SM3. This in-ear monitor made me a true Balanced Armature fan, as it eliminated nearly all of the problems that I had heard with the Shure SCL4 (due to three Balanced Armatures instead of one).

After a year with the in-ear monitor, I wanted even more quality. So I decided to purchase a custom in-ear monitor (required an ear impression from an audiologist): the JH Audio JH16. With 8 Balanced Armatures in each earpiece (4 for lows, 2 for mids, and 2 for highs--for a total of 16 speakers with two earpieces), I have never heard such quality produced from an audio device in my life.

Don't ask me how much it cost me though! (You don't need to spend much to enjoy the sound of a Balanced Armature!)

Saturday, March 19, 2011

Noise Isolation vs. Noise Cancelling

I've decided to start a "mini-series" of posts for my blog regarding audio and headphones/earphones and other audio gear (amplifiers, speakers, etc.). I think these posts will be beneficial to anyone looking to get the best sound quality out of their music! Personally, I have been upgrading quite a lot over the past few years, and reading a lot of audiophile information on forums like I will try my best to help others with the information I've obtained over the years.

I'm sure many of us have heard of Noise Cancelling headphones by now. But do you truly know the difference between Noise Cancelling headphones and Noise Isolating headphones/earphones?

Noise Cancelling headphones work by "fighting sound with sound" by emitting opposing frequencies that cancel out external noise. Above, Sony MDR-NC60 headphones.
Noise Cancelling headphones, quite simply, fight sound with sound. Since there is usually ambient noise external to the headphones that leaks into the music, Noise Cancelling headphones actively "remove" this unwanted sound by emitting frequencies that cancel out the opposing sound. The end result is that you hear your music without all that external noise from outside leaking in.

Noise Isolating headphones/earphones work a little bit differently. Noise Isolating headphones/earphones (more properly, IEMs or in-ear monitors) passively remove external noise without producing opposing frequencies. How they do this is quite simple: they create a seal in your ear or outer ear. For example, many "canal phones" that you insert deeper into your ear than you would iPod earbuds, are creating a seal in your ear that reduces external noise from anywhere between -20 dB and -47 dB. This prevents external noise from coming into your ears at all, thus eliminating the need to "fight sound with sound" as Noise Cancellation does.

Noise Isolating in-ear monitors (IEMs) work by passively reducing external noise by creating a seal in the ear canal. This eliminates the need to "fight sound with sound". Above, Shure SE535 in-ear monitors.

So which form of technology is better? Frankly, Noise Isolating would get the vote from me. One of the main reasons is that Noise Isolating headphones/earphones do not introduce artifacts into the music as Noise Cancelling headphones/earphones do. Since Noise Cancelling headphones/earphones fight external sounds with opposing frequencies, they have a tendency to introduce artifacts into the music that were not originally there. Noise Isolating headphones/earphones do not fight sound with sound, so they never introduce any artifacts into the music.

Secondly, Noise Isolating headphones/earphones do not require any external electricity or power to work. Many Noise Cancelling headphones/earphones require a battery of some sort in order to run the Noise Cancelling feature. This requires charging or replacing batteries, something that Noise Isolating headphones/earphones do not require.

And finally, Noise Isolating headphones simply work better in my opinion. Since sound is never introduced to the ear in the first place (because of the seal), you don't have to fight sound with sound. It's akin to solving a problem before it happens. With Noise Cancelling headphones/earphones, the external noise already gets into your ear and music while it is simultaneously alleviated with opposing frequencies. There's no saying that one technology is better or worse than the other--it's just that Noise Isolating gets the vote from me in preserving good audio quality.

Tuesday, March 15, 2011

Markets Across the World Tumble

Japan's devastating Earthquake, Tsunami, and now their growing nuclear crisis has caused a domino effect across major stock markets around the world. Additionally, with the crisis in Libya still continuing as Oil maintains high price levels, any growth that was expected this quarter might be permanently hindered by the combination of both events.

The Nikkei 225 fell more than 14% in mere days.

The Nikkei 225 Index dropped more than 14% within a mere few days--a landslide in terms of market performance. Tokyo Electric Power dropped more than 24% just today. The numbers are indeed devastating for the Japanese economy, which is already set back by their enormous debt which is the highest for any industrialized, developed nation.

The Dow fell 1.71% during intraday trading (approximately at 1:30PM), while the Nasdaq and S&P 500 fell 1.72% and 1.68%, respectively. The FTSE 100 dropped 1.38% during trading. Oil fell 2.61% to settle at $98.55 per barrel--which is still considered a high price.

The Dow fell 1.78% during intraday trading (approximately 1:30PM).

What does this mean for the global financial markets? For one, it certainly means that projections and forecasts will change for any corporation. Since many products rely on a long production chain that involves multiple countries cooperating, the disaster in Japan combined with high Oil prices will cause changes in these projections. Secondly, the bull market that the U.S. stock market experienced since Q4 last year to now may finally taper off and begin stabilizing.

However, there is some good news in all this. Many analysts believe that the crisis in Japan will finally lead to Japan's recovery from its decades long stagnant economy. Since money will be poured in to help the relief effort, one can expect construction, energy, and food supply & demands to also coincide with the relief effort. This may just be the catalyst for the beginning of a much better economy for Japan, which has experienced a slow, crawling economy for many years.

Friday, March 11, 2011

8.9 Magnitude Earthquake and Tsunami Hits Japan

An 8.9 magnitude earthquake hit off the coast of northeastern Japan earlier today. The earthquake consequently created a 10 meter (approximately 32 feet) tsunami which swept into land, pulling ships onto shore and carrying cars further inland.

The earthquake was originally estimated to be around 7.9 magnitude (Mw scale), but later was confirmed to be an 8.9 magnitude earthquake (Mw scale).

Cars riddled in water brought inland by the tsunami.
Source: Agence France-Presse/Getty Images

The tsunami caused unrest throughout the country, including Tokyo where subway service was suspended and power was cut off for approximately 4.1 million houses. Looking ahead, it looks like any damages caused by the earthquake should not be as significant as the tsunami itself, since many of Japan's modern buildings are built to resist large-magnitude earthquakes. Tsunami's on the other hand are much harder to defend against.

Major airports temporarily in Japan halted flights. Financials were affected as both the Yen and the Tokyo Stock Exchange experienced losses.

The epicenter of the earthquake in northeast Japan.
Source: The Wall Street Journal

With Japan already experiencing an economic slump and internal political problems, this only adds more tension to the land of the rising sun.

As a student minoring in the Japanese language, this is hard for me to witness. I appreciate Japan as a country and its rich culture and people.

Let's hope that people get the help they need quickly and efficiently.

Wednesday, March 9, 2011

Western Digital to Buy Hitachi's Hard Drive Sector

No pun intended on the title (hard drive, bad sectors--bad joke? I know).

Yesterday, Western Digital announced that it would be purchasing Hitachi's hard disk drive (HDD) business for approximately $4.3 billion (in a mixed purchase of both cash and stock). Hitachi would own around 10% of Western Digital's stock after the transaction. This would make Western Digital, already the biggest manufacturer of hard drives in the world--an even bigger hard drive manufacturing giant.

A hard disk drive read/write head and platter.

Currently, Western Digital has a market share of around 31.0%, right above Seagate's market share of 29.7%. After the purchase, Western Digital's market share of the hard drive market will shoot up to a staggering 50% or higher, according to forecasts. However, this brings in the question of whether or not Western Digital will be potentially monopolizing the hard drive industry. Antitrust issues may prevail unless the deal is approved by authorities and not found to damage competition in the market.

However, both Western Digital and Hitachi have stated that they expected the deal to go smoothly and to finish by the third quarter this year. Upon breaking of the news, Western Digital's stock rose by a sharp 16% to $34.68. For a stock that has been down more than 11% for the past year, such a rise is more than welcome by stockholders.

The top 5 main hard disk drive manufacturers, which will be reduced to 4 after the transaction between Western Digital and Hitachi.
Source: IHS iSuppli and The Wall Street Journal

Now that the 5 main competitors (Western Digital, Seagate, Hitachi, Toshiba-Fujitsu, and Samsung) have been reduced to 4, what does this mean for the market as a whole? For one, the competition is probably going to heat up rather than getting reduced. With hard drive prices tumbling over the past decade and the advent of portable tablet computers which rely on static memory (see my SSD drive post), R&D may be the only way to lead a market already saturated with products offering nearly the same performance across the board.

It is clear that with this purchase, the future of hard disk drive costs, performance, and value will be altered significantly. Additionally, with a worldwide cap of neodymium by China (which controls harbors roughly 90% of the world's neodymium--a rare earth magnetic metal which is used in everything from hybrid vehicles to hard drives), new technology will almost become necessary in order to keep prices at bay.

Let's just hope that quality control remains the same across the board with all hard disk manufacturers as demand increases with more tablets, PCs, and laptops being manufactured and shipped around the world.

Saturday, March 5, 2011

February Unemployment Falls to 8.9%

The Labor Department released crucial unemployment data this Friday, stating that the unemployment rate fell to 8.9% in February. This has been the lowest level for the unemployment rate since April 2009. However, there is a dent to this number, as the labor force participation rate fell to 64.2%.

The labor force participation rate measures how many individuals either have a job or are seeking a job. If someone is not actively seeking a job, then they are removed from the statistic, which can give a pseudo-statistical number for the unemployment level.

A three year look on the unemployment rate vs. the labor force participation rate.
Source: Labor Department and The Wall Street Journal.

More simply, people who are not actively seeking a job are not included in the unemployment rate, which may be a problem due to the fact that it is not an accurate measure of the amount of people who are simply discouraged from searching due to the economy.

For example, if the labor force participation today stood at the same level as before the recession, then the jobless rate would be a disheartening 11.5% this last February, as opposed to the 8.9% released by the labor department. This goes to show that clearly many Americans are simply discouraged from seeking employment--until more of these individuals are added back into the labor force participation equation, we would not be on our way to a full recovery.

Another important statistic is added payrolls per month. 192,000 payrolls were added this February, which may seem like a lot, but is actually far from what the U.S. requires in order to have a strong recovery. Nigel Gault, a chief U.S. economist at IHS Global Insight is quoted in the Wall Street Journal stating: "To get a strong recovery, you'd want to be adding 300,000 payrolls a month. We're clearly a long, long way from that."

However, with all this being said, it is still a good indicator that we are on our way to a full recovery--albeit in a slow and sluggish manner.

Wednesday, March 2, 2011

What is RAM and Why Do You Need It?

Did you ever use scrap paper in an exam? If so, you just might relate to your computer!

When searching for a new computer to purchase, you are likely to prioritize specifications. Processor speed, hard disk space, video card performance, blu-ray drives, screen resolution, and other specifications all factor into most computer purchases today.

A RAM Module being installed. Next to the RAM module you can see the heatsink and fan on top of the CPU (central processing unit). The CPU communicates often with the RAM, which is why they are near one another.

One of the most important specifications that is often sought after but not understood is RAM Memory (not technically called RAM Memory, since the acronym itself has the word memory in it). RAM, which stands for Random Access Memory, is a type of physical memory that is commonly found in modules inside desktop computers, laptops, smartphones, and all kinds of electronic devices (even your DVR and DVD/Blu-Ray Player).

We all know that hard disk space is used to store data. Documents, pictures, music, videos, and any other data gets stored as bytes onto our hard drive. When we shut down our computer, our data stays there, ready to be retrieved on a restart.

However, RAM acts quite differently from a hard drive's memory. The primary difference between RAM and hard drive memory is that RAM is temporary. Information that gets written and retrieved from RAM is wiped out when you shut down your computer, in contrast to a hard drive's memory which stores the information in-between boots.

So what exactly do we need RAM for? Think about an exam you took. Did you use scrap paper in this exam? If you did, do you remember why you found the scrap paper so helpful? It probably was useful because you stored temporary calculations in it (in two, three, four step problems and beyond). To calculate your final answer, you probably looked more at your scrap paper than the actual exam sheet.

After the exam is over, you probably ended up with a messy sheet of scrap paper, but landed a score of 100 on your exam. Well, RAM works the same way as your sheet of scrap paper!

A brief diagram showing how RAM fits into the entire computer system.

See, when you start a program on your computer, your computer (specifically, your CPU or central processing unit as shown in the image above) gathers the files and information necessary to run that program. Some of this data is stored temporarily in the RAM module(s). When you work within the program (suppose you are using Microsoft Word), anything you are typing is actually being written onto your RAM--not your hard drive. It is actually when you save your document that the information is transferred from the RAM into the hard drive.

Why does the computer do this? The same reason why you used scrap paper in that exam. The computer needs a faster, more temporary solution for its own "calculations" before it can store the file or data that you need it to--this faster solution is RAM. Since RAM does not have any moving parts as compared to a hard disk drive, it is a much faster form of memory compared to a hard drive. And for a computer, it is this speed and temporary memory that is essential for giving the end-user a seamless experience when using a program.

And when you exit the program, the computer deletes the information from the RAM to free up space for other programs that may be executed--just like when you completed your exam and threw out your scrap paper, the computer does the same.

So the next time you're using a program (or 10 simultaneously in this day and age), remember, your computer is working hard to communicate, write, and retrieve data from RAM in order to give you a smoother experience (or maybe it just needs the sheet of scrap paper for that long-answer question we all hate, who knows!).