Frequently Asked Questions

1. What is the best headphone/amplifier/DAC?
What is the best automobile today? A Ferrari Enzo supercar can go really fast around a race track, but it’s probably useless for a trip to the beach or grocery shopping (I’d rather have a big SUV for those trips). And while the latest BMW 7-series may be one of the most comfortable sedans around, again it’s pretty useless for off-road trips. Vintages like the Ferrari Dino are also nice for certain reasons, but a reasonably priced Acura sedan these days can probably beat it in 0-60 times, gas mileage, and comfort levels as well. The point is that there is no single best, ultimate, can-do-it all headphone, just like there is no such thing in automobiles. It all depends on the type of music you listen to.

From Classical to Rock to Electronica, they all need different things. If you’re listening to Electronica, bass quantity and quality would probably be more important than soundstage imaging or micro details. So a headphone that’s good for one genre may not be as good for another. There are some headphones with a fairly wide genre-compatibility factor, and we call them “all rounders” or headphones with good genre bandwith. On the other hand there are headphones that are really good at specific things and for certain music, but are awful for others.

2. Will I notice the difference if I upgrade my gears from A to B?
Sometimes the difference between audio gears can be subtle, yes, but that doesn’t mean that they all sound the same. It also depends on the listeners, just as I can’t differentiate the taste between a cheap wine to a $1,000 a bottle wine so for some people picking out the difference between DACs can be difficult.

Amplifiers and DACs alter the signal in a more subtle way than a headphone transducer does, and the difference may or may not be too obvious, depending on the resolution of your headphones and overall system, the quality of the recording you listen to, and most importantly how sensitive your ears are. Most people probably can’t tell the difference between a 1-2 psi change in tire pressure, but a good race car driver can.

3. What is the most important part of a Hi-Fi system?
First and foremost is the ears — if they can’t pick up the difference then there is no point upgrading.

The next most important thing is recording quality. Recording quality is a very big factor in the overall Hi-Fi chain, as you simply can’t get a good sound with a bad recording. Good music is always good music regardless of the recording, but the recording is what will give you that Hi-Fi sound through your headphones. Try playing a mono Beatles recording through your $50,000 headphone system and you’ll know what I’m talking about. Sadly, many great music and albums have sub-par and even bad quality recordings.

It’s also important to be able to differentiate the different types of recordings so you can tell if a certain fault in the sound is caused from the recording or from the headphones. A very common example is sibilance. Some recordings have very high level of sibilance and it’ll show through in almost all headphones — that’s not the fault of the headphone. Another important fact to notice is the recording technique. Most Pop/Rock recordings these days are done in a closed, soundproof studio, and there would be no real soundstage inherent in the recordings. So don’t blame your headphones if the soundstage sounds flawed, constricted, or artificial, because that’s not the fault of the headphone.

Live recordings are almost always the best types of recordings to evaluate the overall acoustic performance of a headphone — there you’ll be able to tell an accurate soundstage from a fake one, micro detail levels, ambiance feel, et cetera.

4. What is the most accurate headphone system — the one that sounds closest to real life?
High end headphones tend to have higher levels of fidelity than standard Hi-Fi headphones, but as for which is the most accurate, that is impossible to say. Why is it impossible? Because again, recordings differ greatly from one to the next.

Take two solo piano recordings, for instance. The piano on recording A sounds darker, while on recording B sounds brighter. This is because of variations done in the recording process, anything from the brand of the microphone, microphone angle, microphone distance, microphone height, room dimensions, the material of the wall, the material of the floors, up to the difference in the piano itself. Any slight changes to any of those variables will produce a slightly different piano tone, and when they are stored into a recording format, you will get two different types of piano tones. So in that case, say a Beyerdynamic headphone sounds very accurate with piano recording A, while a Sennheiser headphone sounds very accurate with piano recording B. Then how are you going to pick between the Sennheiser and the Beyerdynamic?

Now that’s just a simple piano recording. Add in brass instruments, wind instruments, strings, vocals, guitar plucks, drums, cymbals, each instruments with their own little variations and it’s almost impossible to say which headphone system is the most accurate sounding since the recordings by nature never have an absolute standard in themselves. Same thing with vocals. The same singer, singing in different venues, with different microphones, holding the microphones at different distances, will produce a slightly different vocal recording. As a matter of fact, it’s actually quite common that the songs in one CD album come with different levels of recording qualities. I don’t know why that is, perhaps they assign the best sound engineer only for the potential hit tracks.

So the next time you hear someone say that headphone A has the most accurate guitar plucks, you can assume that all the guitar CDs that he has in his library are recorded in the same venue, with the same guitar, microphones, microphone stands and positioning, and by the same recording engineer. Or he is only listening to one particular CD/recording when he made that statement.

5. Do I need an amplifier?
When I started my headphone journey, I couldn’t tell why everybody insists on using amplifiers as my ears couldn’t pick up the difference. After years of listening, I am now convinced that all amplifiers, good or bad, alter the signal in some ways (read: it can improve, or degrade the sound).

The new rule of thumb on amplifiers is that if you are using a big circumaural headphone (the one that covers your ears), regardless of the impedance or sensitivity rating, an amplifier in most cases would help. This is extremely true if you are talking about driving the headphones from a portable player, a mobile phone, or a laptop. Even if you can get the volume to go loud enough, a separate amplifier will do a better job in delivering current which will improve bass punch, among other things.

Medium sized headphones, say like the Sony MDR-7506, Audio Technica M-50, or the Sennheiser HD202 would also benefit from an amplifier. Small portable headphones like the Sennheiser PX100 or the Jays V-Jays can still benefit from an amplifier, but sometimes I skip them since I am not that picky when listening to music from small headphones.

6. What is a DAC?
When you are playing from a digital music source (CD, MP3 and so on), the music data is stored in the digital format (i.e 1001010101010110101). It needs to be converted to an analog format before it can be played into soundwaves, that’s what the DAC does, convert the 0101010101 to analog. Thanks to paconavarro for the edit.

7. What is a DAP?
DAP stands for digital audio player, such as the Ipod, Zune, etc.

8. What is an LOD?
LOD stands for line-out-dock and is a cable built specifically to tap the music signal from a DAP’s line out. The signal from the line out is always cleaner and of higher quality than from the headphone out.

9. What do you mean by “bright”? (i.e a bright sounding headphone)
Bright refers to a headphone with a lot of treble presence.

10. What do you mean by “dark”? (i.e a dark sounding headphone)
Dark is the opposite of bright, hence it refers to a headphone with little treble presence.

11. What do you mean by “bassy”?
Bassy, as in a bassy headphone, means a headphone with a lot of bass. Also known as a basshead headphone.

12. What is a boomy bass?
A boomy bass is bass without good control — boom boom boom. The opposite of a “tight” bass — bass with very good control.

13. What is PRaT?
PRaT stands for Pace, Rhythm and Timing, or simply known as “the toe tapping factor”. Some fast paced music requires a good PRaT otherwise the energy of the music is lost in the headphone/amp/system. If you want to test a system’s PRaT, try playing a fast Rock music (ie Muse) and see if you can get the energy from the music. Systems with slow pace, low PRaT will kill the energy and over mellow the presentation.

14. What is Cold/Warm?
Cold and Warm are used to describe the character of sound. A good example would be comparing a Compact Disc to a Tape/Vinyl, where the same song played through a Compact Disc would sound a lot colder than through Tape or Vinyl.

15. Multi Driver IEM versus Single Driver Full Size Headphones?

Briefly:

Multi driver IEMs:
PRO
- Easier to tune to a perfect frequency response as the designer intended. – Multi driver usually means more complete frequency presentation, especially at the bass end. – BA drivers means good articulation across the frequencies, no instruments getting mixed up. – Easier to drive, doesn’t demand a high current amp.

CONS
- Multi driver usually is less coherent than single driver IEM or headphone. – Multi driver IEM doesn’t have the refinement of the big flagship headphone drivers.
Big Full Size Flagships:
PRO
- Overall fidelity, sound quality most of the time better.
- Single driver gives a very coherent sound.
- Scales up better to more sophisticated amp/DACs.

CONS
- Harder to pull off a perfect tonal balance, which often also results in a more polarizing presentation. ie Awesome with this music, not so with that music. – Can’t deliver an equally “complete” frequency response as a multi driver BA IEM.
Hope that helps.

16. Balanced versus Unbalanced Amplifiers

(this is very different than talking about XLR versus RCA interconnects which mainly deals with removing interference from the signal)

Balanced amplification was initially a feature seen on the flagship $2,000+ desktop amplifiers. It makes sense to have them priced as a flagship, since a fully balanced amplifier require twice the amount of circuitry of single ended (or unbalanced) amplifiers. Not to add the additional requirements such as the dual mono power supplies (though not a must, but often goes together) and dual transformers, quad-stack potentiometers, additional input and output paths, bigger chassis requirement, heat management, and so on. So, if a single ended amplifier costs $1,000 to make, then the same amplifier in balanced configuration would at least double that cost into the $2,000 region. The long associations of balanced topology with flagship models somewhat correlates to the “ultimate set-up” stigma surrounding a balanced amp, while it is not always the case.

What happens in a balanced topology is that you have two amplifiers driving one side of your headphone, and another two driving the other side of your headphone for a total of four amplifiers working simultaneously to drive one headphone. On a conventional unbalanced topology, you only have one amp driving one side for a total of two amplifiers working simultaneously to drive one headphone. Because two is better than one, then four is certainly better than two? At least that’s what you often hear — and it does make sense to a certain degree. When you have two amplifiers driving one side of your headphone (aka two amplifiers driving one driver), you get double the slew rate, which will improve the amp’s square wave response and make it more accurate to the input signal. Feeding a fully balanced signal also helps to raise the effective gain, giving you double the amplitude of the same signal, unbalanced. So, with a fully balanced system, you get twice the voltage swing, and twice the slew rate as the same system running in single ended. Power output will increase due to the increase in voltage, but due to heat and current output constraints, probably slightly less than double the single ended output. Good stuff, but amplifiers are not merely about voltage swing, slew rate, and power outputs.

If I talk to people in the high end audio circle, surprisingly very few of them are even aware of the unbalanced vs fully balanced debate. They would go into lengths debating the merits of branded power cables and even branded IEC connectors, but, interestingly, for them balanced or unbalanced is just something that a pre-amp manufacturer may choose to include for compatibility with studio gears. Now, it happens that every headphone enthusiasts that roams the internet knows the benefit of balanced drive. My brother in law happens to be in favor of a balanced system for his 2-ch set up which consists of a Mark Levinson No.32 preamp, some Krell monoblocks and a pair of Magnepans. But even then, the Krell monoblocks doesn’t output a differential signal to the Speakers (the Magnepans’ transformers are what created the differential signal to the ribbons). Are speaker guys really that ignorant?

As with everything in life, you have to look at both sides of the coin. The transistor vs vacuum tube debate. The discrete vs chip debate. The single vs multi drivers debate. The push-pull vs single-ended debate. The OT vs OTL debate. The Planar vs Dynamic debate. Sennheiser vs AKG debate (just kidding). And this time, unbalanced vs fully balanced debate.

So, what’s the downside with balanced amps? I’ve played around with a few balanced amps, both big and small, also the four portables being discussed. What I witness is that although the soundstage widens, the imaging accuracy and center image in general, suffer. Several factors come into play here. First and foremost is the issue of component matching. Very critical in obtaining a perfect symmetry between the right and left channel, which would in turn affects the soundstage image. Matching for pairs is not that difficult, but matching for quads are far more difficult. I am building an electrostatic amplifier at the moment, and I’ve yet to come up with a decent paired quad after going through 40 pieces of transistors ordered from the same vendor (and likely close in manufacturing batch). The Beta22 amplifier comes with 30+ transistors in one channel, and at four channel, that means matching 120+ transistors, not to mention the diodes and the resistors. Now, if you’re talking about a medium-large quantity production such as these amplifiers, how tight of a tolerance can you afford to implement on the assembly line? The effect of component asymmetry can be quite profound when you’re listening critically through headphones.

The second factor is space constraints. Although I am not familiar with the circuit design used in these amps, it’s common sense that it’s easier to build a good amplifier if you have a big enclosure to design a circuit around. There are exceptions of course, like the 47Labs Gaincard, but most high quality amplifiers come in really large enclosures. The third factor may sound insignificant, but also just as important: volume control. As of now, all these balanced portable amps are limited to the lower resolution analog potentiometer options, whereas the unbalanced amplifiers come with fancy digital volume controls and stepped attenuators. Analog potentiometers are very critical to the input signal, and this puts the balanced amplifier in a strong disadvantage against single ended amplifiers that come with sophisticated volume controls.

One of the reason that desktop balanced amps sound so good is that they have all the space they need to double the size of the amplifier circuitry without having to cut corners. High quality balanced volume controls are also plenty. And given the premium price the desktop balanced amps command, they can afford to be critical in their component matching. With the portables, however, there are a lot of constraints with a portable balanced amp, and so the result has been quite mixed. Some people love them, some people hate them. Some people love the wider and bigger soundstage that they get, some people hate the inaccurate imaging and the lack of a proper center image. Some people love the bass response, some people prefer a more articulate and the better texture of the single ended amps.

I think it boils down to each individuals, and what they are looking for in an amplifier. But the bottom line is quite simple: The balanced amps here give you more power output, wider soundstage, and more bass quantity. The single ended amps here will give you better soundstage imaging, some of them have better resolution levels, and better articulation.

17. How long do I need to burn in my headphone for?

I think it is inaccurate to say that headphones need hundreds of hours before they open up. In my experience most headphones settle down within 12-24 hours. Here is an article that is somewhat related to the topic of burn in: Burn-in and Production Variations.

18. What is the recommended way to burn in my headphones?

While people come up with recipes that includes frequency sweeps and pink noises, I personally just let some music flow through the headphones.

19. Why is Toslink considered inferior to Coaxial S/PDIF and USB connection for Audio Playback?

The digital signal is actually transferred natively as an electrical signal (how else would you do it otherwise). With Toslink, the electrical signal needs to be converted to an optical signal for transmission over the toslink cable, then reconverted back to electrical at the DAC end. Whenever you have these additional conversions/processes, it’s another window for Jitter. With Coaxial S/PDIF and USB such conversion is not necessary.

20. How do I know if my headphones are wired with a reverse polarity?

First, a reversed polarity is not when you switch out the left and right channels (that’s reversed channels). A reversed polarity is when you wired the + and – incorrectly, like swapping the red and black wires on a speaker set up.

The most obvious effect of a reversed polarity wiring is on the soundstage image. Things that are supposed to play in the center of the soundstage image (that’s right in front of your forehead) instead is like split into two and now playing on the left and right edges of the soundstage image.

Do this for illustration purposes: take both of your hands and put it in front of your forehead. With a correct polarity (and a good heapdhone and a good recording), a certain singer or instrument would be projected there right in front of your forehead.

Now, spread your two hands apart to the left and right. This is how an incorrect polarity would sound. The instrument or the singer is no longer in the center, but rather split and is now playing on the left and right edge of the soundstage image.

Other effects of a reversed polarity may include a shift in the frequency balance. You may get more treble, less midrange and such. Of course this may be give the impression that the headphone is now better (i.e with more treble comes more apparent detail), but the fact is that the soundstage image is plain wrong.

The best recording to evaluate this phenomenon would be a good live recording. A one instrument live recording like live piano solos would be even better since you have no distraction from the other instruments.

Some headphones like the Grado HP1000 comes with the polarity switch (so you can reverse the signal at will) but I personally have never encountered a recording with an erroneous polarity so I don’t see what the need is for such switches (Although I don’t doubt its cool factor). Likewise some DACs like the Cambridge Dacmagic also comes with a polarity reverse button. If you happen to have the Dacmagic you can play around with the button to see the effect of a reversed polarity.

– work in progress –

Please submit any additional FAQ you feel necessary down at the comment section. Thanks.