Tag: MP3 player

What It All Means: Frequency Response, Impedance, Sensitivity, and Drivers

As headphones of all types gradually become  fashion accessories, important technical measures of performance with unglamorous scientific measures seem to be preeminently targeted for exclusion by many manufacturers. Further still, even when manufacturers supply technical information, it can often be overlooked and placed beneath less pertinent factors to listening experience and sound reproduction such as model style, crafty novelty, and brand name. Just as one would not purchase a new set of reading glasses because they look “cool” without first considering the appropriate magnification, buying headphones requires that buyers are equally aware of the characteristics that best fit their particular needs. Whether it is a total suppression of relevant information or lack of knowledge surrounding the specifications that make a true difference in sound reproduction, purchasing headphones of any type based solely on emotive judgement can  result in an inadequate and unsatisfying listening experience. To help you make your next headphone purchase as a discerning and refined buyer, this blog will explain the importance and relevance of their most crucial technical specifications.

In the following sections we will define and explore the effect on listening experience of specifications including Frequency Response, Impedance, Sensitivity, and Drivers (which classify better as components rather than a characteristic, yet are imperative to sound quality). This list covers only the most common specifications and do not take signal quality or signal source into account.

Frequency Response

The Grado SR225i features a frequency response between 20 - 22,000 Hz, well within the average human range

Perhaps the most controversial specification among audiophiles, the frequency response uses Hertz (Hz) as a measure of sound waves per second where 1 Kilohertz (kHz) = 1,000 Hz. In reference to headphones, and speakers in general, the frequency response describes the frequencies a set of headphones can produce. Essentially, the lower end of the frequency response indicates the lowest frequency the speaker can produce while the larger number describes the highest frequency the speaker can produce. This, of course, does not necessarily translate into sound heard. The reason for this is because human hearing averages between 20 Hz to 20,000 Hz. What makes this measure particularly polarizing is the general assumption that a frequency response with a lower Hz measurement translates into a better bass reproduction. While a frequency response lower than 20 Hz can be taken as a strong indicator of the potential bass reproduction, measures beneath roughly 16 Hz are felt as sound pressures rather than audible tones. The same logic that applies to bass applies to the treble scale. Sound above roughly 22 kHz tend not to be audible. As a general principle when shopping for headphones, buyers should at the very least be sure to accommodate for the average audible range for human hearing with a safe amount above and below the human hearing range. For example, a set of headphones with a frequency range of about 16 Hz – 23 kHz is  adequate for most casual listeners. Nevertheless, frequency response should not be the lone factor in deciding a purchase, there is plenty more to consider.


The Sennheiser HD 650 features an impedance of 300 Ohms making it practically impossible to play with only a portable device

Without complicating matters too much, impedance basically indicates the power demand of a headphone and is most useful to buyers as an indication of a headphone’s application. Impedance is measured in Ohms and when thinking of impedance it is useful to separate into low and high impedance categories.

Low impedance headphones ranging from around 32 ohms to around 100 ohms are particularly well suited for portable applications. Because low impedance headphones require less voltage to produce high volume, a battery powered MP3 player or a portable device like an iPod have enough voltage to allow the voice coil and magnet to push and pull the speaker in the appropriate direction.

On the other hand, high impedance headphones are intended primarily for high-powered applications. High impedance headphones require more voltage from the source in order to reach comparable volumes to a lower impedance headphone. Nonetheless,  at a higher impedance, the tightly wound, thin voice coil wire creates resistance and results in a greater magnetic field that allows a more responsive diaphragm allowing high impedance headphones to push and pull the speaker with greater ease. High impedance headphones can be used with portable devices if they are paired with an appropriate headphone amplifier that will provide the high impedance headphone enough voltage to convert the electrical signal into music.


In direct relation to impedance is a headphones sensitivity. While impedance describes the voltage necessary to power the headphone at a specified volume level, sensitivity is describes the amount of electrical signal that is converted into sound.  The relationship between sensitivity and impedance is such that sensitivity is a direct result of voltage. In other words, sensitivity tells users about the volume level, measured in decibels (dB), at a specified voltage.  So, if you know the impedance of a set of headphones and the power supply, sensitivity can give users a good idea of the volume you can expect for a set of headphones.


Finally, the driver. Easily the most important part of a set of headphones as this is the place where the music happens. Although there are many types of drivers available to consumers, perhaps the most common is the dynamic driver. All the specification discussed up to this point directly affect the performance of the driver. Of particular importance is the driver size, as this most often indicates the type of frequency the driver will best suited to reproduce.

The old adage that bigger is better is only partially true in regard to headphones. For instance, if the goal is to get the most bass out of a pair of headphones and have made sure to see that the frequency response of the headset is sufficiently low, then a large driver may be the best option. Because a large driver with a larger surface area will push more air through the chambers, the large driver is best suited to provide the best bass response. Moreover, because of the large surface area, the pressure of inaudible frequencies will be more noticeable.

However, if your musical tastes and demands tend toward the higher frequencies, a larger driver is antithetical to your purposes. Higher frequencies travel in faster and tighter waves than the broad bass frequencies. This means that your driver will need to respond quicker and fluctuate faster than it would need to with low frequencies. Smaller drivers, with a smaller surface area and reduced mass, are much easier to move making it the most appropriate option for mid to high frequencies.


Despite the continuing trend toward marketable and trendy headphones, these devices are complicated and technologically advanced pieces of equipment that have developed over many years. Understanding how to get the most of a set of headphones require a dedicated degree of commitment and personal investment. Ultimately, the diligence necessary to fully appreciate the characteristics of a pair of headphones can be the difference between just another mundane experience and a lifetime of enjoyment.


Quality Versus Convenience in Music

As the music industry continues to shift away from CD’s and toward compact MP3’s, AAC’s and other digital files, we can’t help but wonder what kind of quality is really associated with each file type. The way we store our music for future playback is also a big factor when it comes to how the music sounds when played through your car stereo. Has the goal of the industry been to deliver the best sounding music for the best price? Absolutely not, in reality consumers are trying to downgrade their music libraries into a workable solution that is the MP3 player.

File Types and Quality

A good knowledge of different song file types will aid you in deciding how you want to play your music. First and foremost, CD’s are one of the best ways to play music and maintain a great sampling rate, which is typically 1,411kbps. The only issues with CD’s are the durability of the disc, and the amount of storage space required to hold your library in comparison to the small size of an iPod or other small device. The standard for downloadable music is currently MP3’s. Some people love it, some people hate it, but most people choose to accept it.

Quality Pros Cons
CD 1,411kbps •High Quality Lossless Music
•Most Common Method of Playback
•Majority of Stereos Accept CD’s
•Average of 13 Songs
•Scratched Easily
•Bulky CD Wallets
•WAV Files Are Large in Size
MP3 128kbps
•Small Storage Size
•Fit More Onto Storage Device
•Higher Bit Rates Sound Comparable To a CD
•Loss of Audio Quality
AAC Variable •Standard Music Format of Apple Products •Loss of Audio Quality
WAV Uncompressed •High Quality Lossless Music •10mb Per 1 Minute of Audio
FLAC Variable •High Quality Lossless Music
•Slightly Compressed
•Large File Size
•Not Compatible With Many Devices
•Inconvenient For Playback

Devices and Quality

The device you choose to play your music from also has its own ups and downs. USB Thumb Drives are fantastic for conveniently loading your favorite music onto. You may plug it into a USB port in your car for playback directly off the drive, although you are typically limited to 4 GB of space. The iPod can store thousands of songs and give you access to hundreds of playlists in a single device. The downfall is that all music on an iPod is compressed, which results in bad quality. Whether you use an auxiliary input or a USB connection makes a difference as well. USB will digitally transfer your music from a portable device and process the music through your head-unit, while auxiliary connections are analog and will sound slightly diminished to that of USB devices. When using AUX, avoid turning the volume up too loud on your portable device to eliminate clipping.

Pros Cons
Flash Drive •No Need For 3rd Party Software
•Small and Compact
•Stereos Usually Limit at 4 GB
•Organization of Music Can Be Difficult
iPod / Zune •Convenient For Playback
•Easy Organization of Music
•Major Loss of Audio Quality
CD •High Quality Lossless Music •Average of 13 Songs
•Scratched Easily
•Bulky CD Wallets
•WAV Files Are Large in Size
Aux Input •Universal 3.5mm Input
•Control Through External Device
•Analog Connection
•Slight Loss in Quality
USB Connection •Digital Connection
•Charges Your Device
•Typically a Premium Feature

There is no wrong or right way to play your music in your car. Everyone has their own preference of devices, and some people much prefer the convenience of an iPod versus the bulkiness of a wallet of CD’s and vice versa. Let this guide help you to decide the best methods of playing your music, and to help you understand that there is a significant difference in quality and storage space when comparing different file types. Please share with us your opinions and methods of playing your music using the comment box below, we would all love to hear from you.


Eclipse CD3414 In-Dash Car Stereo

CD3414GBy Gideon V. – Sonic Electronix Editor

Are you looking for a great car stereo that won’t break your budget? The Eclipse CD3414 is a steal of a deal at $74.99 with free shipping! This in-dash CD/MP3 player is one of the best values on our website. While most entry level head units only play CDs, this unit can also playback MP3s and WMAs. Besides, it also has a built-in AM/FM tuner with numerous presets for storing your favorite radio stations. When it comes to tuning, the dual rotary controls make it easy to navigate thru your music library. With the simple turn of a knob you can adjust the volume or to switch radio stations. This easy interface makes your driving experience safer and more convenient.

In terms of expandability, this unit has two sets of preamp outputs, making it easy to add amplifiers to your car stereo system. The built-in aux input gives you the option to connect a portable media player such as an iPod or iPhone. Just use the rear audio RCA input to add all of your favorite portable media devices. Eclipse stereos are know for their excellent sound quality. No matter what you add to this stereo, the sound quality is exceptional and rates off of the charts. The built-in equalizer has preset tone curves, so you can adjust the EQ based on the style of music you are listening to.

This sleek in-dash car stereo features a dot matrix LCD display for easy viewing of song titles and artists. The knobs and buttons are styled with green lighting, making for a flashy look. In this day and age, it is important to protect your aftermarket car stereo components against theft. This Eclipse stereo has a built-in Electronic Serial Number to prevent thieves from using it. This feature is intended to deter theft, and this unit even includes stickers warning of this feature. You can post these stickers on your vehicle to warn thieves that this unit is traced electronically.

This head unit is available at an unbeatable price. Make this stereo the centerpiece of your car stereo system and use it to power your speakers. This stereo has an internal amplifier that can provide 17 watts of RMS power by 4 separate channels. At a price of $74.99 with free shipping, you simply can’t go wrong–and this unit is definitely the right choice.