Category Archives: Audio

JDS Element vs Meier Corda Jazz

This is a detailed comparison of the Corda Jazz with the JDS Element. I own one of each and listen to them almost every day, along with an Oppo HA-1. I’ve reviewed each of them separately.

TL;DR Summary: If all you need is a pure analog headphone amp, get the Corda Jazz. It has all the clean neutrality of the JDS Element, but richer, sweeter, more refined. If you want the flexibility of having a DAC and analog RCA inputs and outputs too (even if you won’t always use them), get the JDS Element.

Similarities

Cost: Both cost the same (about $350).

Provenance: Both are built by very small independent companies. Both are designed and built with a no-bullshit engineering philosophy.

Sound Quality: Both have excellent sound quality both subjective and measured that could be considered “reference” from an objective perspective, meaning it’s hard to differentiate them from each other, or from top end reference gear in a properly done level matched DBT. Of course, that doesn’t mean they sound the same (they don’t). In my opinion, they’re in the same league as the best gear I’ve heard costing a lot more, and their relatively low price is the only reason they might not be considered “audiophile” in some circles.

Gain: Both have adjustable gain separate from the volume knob–a switch for high vs. low gain. This enables them to drive anything from efficient IEMs that only need millivolts and milliwatts, to big power hungry planar magnetics.

Power: Both have > 1 watt max continuous power output, enough to drive almost any headphone on the planet, except for electrostats which need a dedicated voltage step-up transformer.

Reliability: I’ve used both near daily for more than a year with no problems.

I believe any pragmatic audiophile (myself included) would be delighted with either one, so long as he valued sound quality and neutrality over fancy knobs, glowing displays and the exclusivity of limited production boutique equipment. Actually, each of these does provide some of the latter exclusivity despite their low price, being less common than mass-produced gear from major manufacturers. When people see one on your desk they ask, “What the heck is that?”

Differences

DAC: Advantage: JDS Element
The Element has a DAC; the Jazz doesn’t. The Element’s DAC is clean, but USB-only and does not run in async; it relies on the source (your computer) to clock the data. JDS claims async mode doesn’t provide any audible benefit, and their measurements support that claim (though that doesn’t necessarily make it true). I do note, when using the  Element, occasional “tics” or brief drop-outs that are not in the source material and occur seemingly randomly. This is consistent with the notion that the clocks (computer source vs. Element DAC) are slightly different and it occasionally re-syncs. This may happen less frequently or never on other computers.

Flexibility: Advantage: JDS Element
If you need a DAC that can drive line-level analog output (for example to a different device), and also a headphone amp, the JDS Element does the job.

The Element has analog RCA line-level output jacks, which the Jazz lacks. The Element also has unbalanced analog RCA input jacks which bypass the DAC and make it a simple analog headphone amp. This makes Element quite flexible as a line-level DAC, an analog headphone amp, or both together. When turned off, the DAC is still on and it routes the USB input to the analog RCA outputs. So you can use the Element as a DAC with line output, and as a headphone amp, leaving both plugged in at the same time. However, it will only drive one or the other, depending on whether it’s turned on. Put differently, think of the Element as “always on” for DAC, line input and output, and its power switch controls the headphone amp.

The Jazz is nothing more than a pure analog headphone amp. It has no analog RCA outputs to drive another analog line level device, nor can this be done from the headphone jack! That’s because of the Jazz’s active balanced ground drive. Line level unbalanced analog inputs assume the entire signal is on the + output, and signal ground is dead zero frame ground–that’s how unbalanced works. The Jazz emits a signal on the ground, which if passed to an unbalanced analog input, would be shunted to ground without any resistor. This makes the Jazz attempt to drive a 0-ohm load, which can blow the fuse or damage the amp. Use the Jazz only to drive headphones — not other audio components!

Volume: Advantage: Corda Jazz
The Element has an analog potentiometer volume control. It’s smooth, wide range, well balanced, but still a pot. The Jazz uses a stepped attenuator triggered by an analog pot; there is no pot in the signal path, only metal film resistors. It has about 30 steps, each about 1.5 dB apart. One can argue whether a stepped attenuator makes any audible improvement, but there’s no question the stepped attenuator is a superior design: cleaner signal with perfect channel balance at all volumes, and unheard of at this price.

Imagery: Advantage: Corda Jazz
The Jazz has a mode to artificially create a more natural stereo image from normal (non-binaural) stereo recordings. It’s a switch that blends channels with phase delay depending on the difference in L / R channels. I’ve used these before and they’re usually gimmicky. Meier’s is not a gimmick. It’s the only one I’ve heard that improves the image while getting out of the way of the music being otherwise sonically neutral or nearly transparent. I said “nearly” transparent. It does make the tone a tad less rich, a small emphasis in the mids to treble. I usually leave it off, except on recordings with extreme L-R separation, where for example a singer or instrument is entirely in one channel or the other. These are hard to listen to on headphones, and this switch fixes that.

Signal Isolation: Advantage Corda Jazz
Both amps have unbalanced analog output to the headphones. But the Jazz adds a twist: active balanced ground driving. Signal ground to the headphone is not the 0V frame ground that it would be with standard unbalanced. Signal ground contains some of the L and R signal combined, such that the net signal at each speaker of the headphone (difference between + and -) sums to pure L or pure R. Because the ground contains some L and R signal, the net field around the cable is near zero (not exactly zero, as it is with balanced). This isolates the signal better, immunizing it to hum or other electrical interference. Some might say this also makes the load easier for the power supply to drive, but the power supply is already over-engineered with its 10 W toroidal transformer.

Build Quality: Advantage Corda Jazz
Both have great build quality, but the Jazz is a small step higher both inside and out: the case, switches, knob, power supply and other internal components. The Element is by no means cheaply made, it’s a pleasure to view and handle. But the Jazz is a step up.

Sound Quality – Subjective Listening

Both sound great: clean, neutral, detailed and fast without brightness, deep bass without being bass-heavy. Both are dead silent even at high gain full volume – no hum or other background noise. Both have excellent measurements comparable to professional reference gear. Not having a DAC, the quality of the Jazz depends on the source. I compared the Jazz & Element using an Asus Xonar DX sound card to drive the Jazz, and driving the Element with a USB bit stream. I used Audeze LCD-2 headphones and extremely high quality recordings of a variety of music, mostly acoustic.

In this configuration, I preferred Jazz in overall sound quality, which countered my expectations since good solid state amps are so hard to differentiate in blind listening tests. The Jazz has the same level of clarity and detail as the Element, yet at the same time sounds slightly more rich in the bass and sweet in the mids and treble. Call it more musical, yet without any loss of neutrality or clarity. I emphasized the word slightly because the difference is subtle. Upon first impression they sound identical, though I feel well trained experienced listeners using excellent recordings would detect the difference consistently with careful listening in an ideal quiet environment.

That said, if I needed the flexibility that the Element provides–listening to music from a laptop where I must stream bits over USB because I can’t install a high quality sound card, or I needed a DAC with line level RCA output in addition to a great headphone amp, or I was using great but less than reference quality headphones like Sennheiser HD-600 instead of the Audeze–I would grab the Element in a heartbeat. To put some meat to that statement, my Element is not for sale.

By comparison, the Oppo HA-1 is the best of both worlds and more. Its analog amp equals or exceeds the Jazz, which is a high bar. Its Sabre ES9018 DAC is fantastic and has coax, toslink and USB inputs. It is fully balanced with both line level and headphone outputs, yet also has a single-ended outputs. It also has great flexibility with numerous inputs and outputs. The only feature it lacks is the Meier’s headphone image circuit, but I only miss it on those rare recordings with artificially extreme L-R separation. But the HA-1 is big and bulky, weighs about 15 lbs, costs 3x the price of the Jazz or Element and is no longer made.

Audio EQ Settings

Since I went to the dark side, and started using gentle parametric EQ to correct the FR of headphones & speakers to neutral, I want to collect the EQ settings here. My general philosophy is to make subtle corrections. FR response deviations are often related to other forms of distortion like phase or ringing. Amplitude corrections big enough to restore completely flat response can exacerbate those other factors. Thus I stick to subtle, gentle corrections that improve neutrality yet preserve the original character of the sound, short of restoring perfectly flat response.

When boosting levels, remember to apply a reduction in overall gain to avoid clipping. Take the biggest amplitude boost at any frequency and cut by that amount. This is in the voltage (not power) domain, so dB = 20 * log(V1/V2).

For example, if you apply +2.5 dB @ 4.5 kHz, then you must reduce overall gain by 2.5 dB, which is a gain ratio of 1 / (10^(2.5/20)) = 74.98%. Or just use 74%. When it comes to gain ratio, to avoid clipping, lower is safer. So always round down (truncate the decimal), not up.

Sennheiser HD-580

Characteristic FR: flat down to 50Hz, then roll off bass at about 6 dB per octave. Gentle dip of about 5 dB between 3500 and 9000 Hz. Narrower dip of about 6 dB between 10 and 17 kHz.

Parametric EQ Correction:

  • +4 dB @ 25 Hz, Q=0.67 (2 octaves wide — 1 each side)
  • +4 dB @ 14 kHz, Q=1.3 (slightly under 1 octave wide)
  • Gain: -4 dB = 0.63 = 63%

Subjective Difference:

This simple EQ transforms the venerable HD-580 making it more open, natural and neutral. Deep bass extension without impacting mid-bass and linearity. Slightly crisper transients and “air”. Even though the midrange is untouched, it sounds a touch more open, less boxy.

Audeze LCD-2

Characteristic FR: flat from zero to about 2 kHz. Gentle dip of about 7 dB between 2k and 9k. Flat from 9k on up.

Parametric EQ Correction:

  • +2.5 dB @ 4500 Hz, Q=0.67 (2 octaves wide — 1 on each side)
  • Gain: -2.5 dB = 0.74 = 74%

Subjective Difference:

Normally the LCD-2 sounds perfectly natural, yet a touch soft like listening from the 5th instead of 1st row, and correspondingly soft on detail. This EQ brings the LCD-2 back to the 2nd row and restores some lost detail, but without affecting its near-perfect voicing. It transforms the LCD-2 into the perfect headphone!

The 2016 and later LCD-2 are a touch brighter and need less EQ. Say 2 dB for these, and 3 dB for the 2014 model. CSD plots show the LCD series headphone tends to ring or resonate around 4-5 kHz, which is the trough of their natural response curve, so you don’t want to boost this freq too much.

Magnepan 3.6/R

Characteristic FR: depends on the room. My listening room has floor-to-ceiling tube traps 2′ diameter in corners behind the listener and 4″ thick RPG acoustic foam on the wall behind the listener. This EQ is busier than the headphones, which is unavoidable with in-room speakers, though I still managed to keep the rates gentle.

Parametric EQ Correction:

  • +3 @ 32, Q=0.67 (2 octaves wide — 1 on each side)
  • -2 @ 90, Q=1.41 (1 octave wide)
  • +3 @ 240, Q=0.4 (1.5 octaves wide)
  • -2.5 @ 1000, Q=0.67 (2 octaves wide)
  • +3 @ 3000, Q=1.41 (1 octave wide)
  • Gain: -3 dB = 0.7 = 70%

Of these, the bold-faced ones correct anomalies inherent to this speaker. The rest are room corrections. That is, the Magnepan 3.6/R is a near-perfect speaker when set up properly in a good room, but it rolls off the low bass and has a gentle lift around 1 kHz. The other 3 settings are corrections to my room.

Ubuntu VLC DAC Audio

I recently got a JDS Labs Element DAC + headphone amp. I drive it from my Ubuntu desktop using VLC as the audio player. It’s plug and play – no drivers needed. However, best results come after applying a few tips:

VLC Audio Device: The DAC has 17 output devices that appear in VLC. Which one to use? Use Pulse Audio if you want to hear a mix of all audio on the computer. Pulse Audio mixes all sources and resamples them if necessary to a common rate. Use JDS Labs Element DAC, USB audio direct hardware device without any conversions if you want to hear the audio track in its native sampling rate & bit depth, and nothing else. I prefer this for best sound quality.

VLC Output Module: use Pulseaudio audio output if you want to hear a mix of all audio on the computer. Use ALSA audio output if you want to bypass Pulseaudio to hear the audio track and nothing else.

VLC occasionally stopped playing and popped up an error saying “Device or resource busy”. If you’re using ALSA, only one app at a time can use the device. For example, if the browser tries to play a video it can steal the device from VLC. Also, VLC seems to have a bug in which it occasionally steals the device from itself when switching tracks. Adding a udev rule made this happen far less often. Add a file called 41-jdslabs-dac.rules to directory /etc/udev/rules.d. Make the contents like this:

# JDS Labs Element DAC
SUBSYSTEM=="usb", ATTR{idVendor}=="262a", MODE="0666", GROUP="plugdev"

This makes the JDS Labs DAC accessible to any Linux user.

Audio Glitches: Occasionally, once every hour or so, the audio will stop for a moment, then resume. I believe this is because the JDS Element uses USB adaptive mode, not async. This makes it compatible with more computers. Some people claim that adaptive move has more jitter and lower sound quality, but measurements belie this claim.

More audio glitches: Occasionally I would hear tics in the music, as if the computer CPU were too busy to deliver audio. Re-nicing the VLC process to -15 fixes this.

Review: Audeze LCD-2 (2016)

What? Another LCD-2 Review? Why? Here’s the background.

I got a second pair to use at work, again from the Headphone folks in Montana. I’ve owned this headphone since 2014 and already reviewed it twice: once when I first got them, again later when I EQed them. Audeze never rests and is constantly improving their products. But they don’t change the model numbers. The LCD-2 has gone through several variants with names the community invented because Audeze didn’t see fit to name them:

  • LCD-2.1: the original version – creamy sound, smooth linear mids with rolled off treble
  • LCD-2.2: same linear mids, improved treble response, yet still on the warm side of neutral
  • LCD-2F 2014: introduction of Fazor, improved detail and transient response, but some people report the treble sounds wonky
  • LCD-2F 2016: lighter re-tuned drivers, further improved transient response

The 2016 LCD-2 is similar to the 2014 overall, with excellent reference quality sound. Since I linked the prior reviews above, here I’ll describe only the differences. Compared to the 2014, the 2016 LCD-2 has:

  • Bass: cleaner, tighter, faster but neither attenuated nor amplified. This is hard to imagine because the 2014 bass was excellent to begin with. Somehow they improved it.
  • High Treble (9+ kHz): cleaner, faster and slightly amplified. A good recording of castanets shows the 2014 was already excellent, but the 2016 is even better. Treble is shelved up a touch and brighter compared to the 2014, but the 2016 is not bright sounding.
  • Mids: different – described below

Comparing the midrange is more complex and takes more than a few words. The 2014 midrange is incredibly smooth and natural and has a slight presence emphasis compared to the 2016. This presence is subtle and to put it in perspective, the Sennheiser HD-600 (a great headphone in its own right) has far more presence sounding boxy or nasal in comparison. I like the 2014 mid presence on small ensemble acoustic music; it brings out the natural timbres of acoustic instruments and voices. But with large ensemble works and big complex music, this presence becomes a slight glare that veils the music. The 2016 lacks this presence, yet it also lacks the glare that comes with it on big complex music. The 2016 still voices acoustic instruments in a natural, realistic way – it’s not midrange suck-out like some headphones have.

So when it comes to the midrange, both do extremely well, yet I prefer the 2014 for small ensemble acoustic music and the 2016 for bigger more complex music.

Overall, the 2016 is better than the 2014 in many ways, but not in every way. The 2016 is more open, faster and more resolving – all good. Yet the 2014 has a special intimacy and realism to the midrange voicing of small ensemble acoustic music.

Note: I contacted Audeze and for $400 they will upgrade any model of LCD-2 to the latest version, which includes new ear pads of your choice and return shipping. I’m leaning toward upgrading my 2014… but haven’t yet decided. If the 2016 was better in every way, I would. But the decision isn’t that easy.

Alternatives

In my experience, planar magnetics wipe the floor with conventional drivers in terms of overall sound quality – both in headphones and in speakers – so I limited my search to them.

I auditioned the HiFi Man HE-500 a few years ago. It was a great headphone but had a weird midrange response that didn’t voice acoustic instruments properly. I looked at other HiFi Man models but none of them have the truly linear frequency response I’m looking for.

I gave the Focal Elear serious thought. Sure, it’s a conventional driver. But it had such rave reviews I considered it. Yet it also had some decidedly non-rave reviews and the specifications showed non-linear frequency response, transient ringing and higher distortion. No thanks.

Finally I decided to keep it simple. I like my LCD-2 so much, why not first try the latest version? If I didn’t like it I could always return it and move on to something else. I found a pair from Headroom, the headphone folks in Montana, that was an open box, so I got a lower price, yet new with full warranty. I’ve been a customer of theirs since 1999 because they are knowledgeable, honest and have a generous 30-day try-return policy.

Review: JDS Labs Element

The Element

See here for background.

It’s a headphone DAC+amp – details here. Since I care about function over form, I saved $50 buying a b-stock version new from JDS. It’s small & light, simple to use and beautiful in appearance. The cosmetic glitches that made it b-stock are truly cosmetic and slight; you won’t notice unless you’re a perfectionist. Inputs are USB and analog unbalanced RCA, so it can be DAC+Amp or just an amp.

The Element comes with an external wall-wart type power supply and a USB cable. The power supply is unusual: a wall-wart style AC-AC whose output is 16 VAC at 1 Amp. That’s 16 Watts for a 1 watt amp – so far so good!

My description of the sound is brief because there’s not much to describe. If you’ve ever heard a well designed and built top quality solid state amp, that’s what the Element sounds like. Spec-wise (curious readers will find specs at the above link) it’s as good or better as anything you will find at any price. And I mean any price – even into the multi-kilobuck range.

I believe specs are useful but they don’t tell the full final story. Absolutely black quiet background: no audible noise at any gain or volume setting. Stark neutral frequency response, all measured distortion (THD, IMD, noise, etc.) at -100 dB or lower. The sound is smooth yet detailed with no edge or grain. It sounds exactly like whatever you’re playing. My first impression was to call this sound reference quality, but a side-by-side comparison with my Oppo HA-1 and Corda Jazz took it down a notch. All are clean and neutral, but the HA-1 and Jazz have a richness in the bass and sweetness to the mids and highs that the Element lacks. This difference is subtle, I hear it only on high quality recordings with my Audeze LCD-2 headphones. It disappears with Sennheiser HD-580s. I don’t believe this is euphonic distortion; the HA-1 and Jazz are honest neutral amps, nothing like the tubuliciuos sound of a great SET amp. Some people call the Element “dry” and I believe this is what they mean. It’s clean and neutral, yet it lacks the last bit of refinement.

The volume knob is big, sits top center, moves easily and smoothly and has a wide range – over 270* of rotation. It’s nicely linear and extremely well balanced L-R.

The Element’s USB DAC can accept up to 96 KHz – 24 bit. When listening to this digital source the amp has considerably less gain. I found this was caused by software mixer settings; after correcting the Element’s DAC and analog levels had about the same level. I used the Element’s low gain setting with my LCD-2 and HD-580 headphones, and it had plenty of unused range to the volume knob.

The Element has unbalanced analog line level RCA inputs and outputs and can be used as a pure analog amp. If you plug in an RCA input it bypasses the DAC. When powered off, the Element powers off the headphone output but is still “on” internally, routing the line level input to the analog output. When turned on, it powers up the headphone output and powers off the line level output. This gives the Element great flexibility as an in-line device and headphone amp.

The Element’s DAC does not run in async mode; it relies on your computer to clock the data. JDS claims this has no audible drawbacks, but my experience belied these claims. I heard occasional tics or brief drop-outs, suggesting that it was re-syncing slight clock differences. These were seemingly random, not reproducible when backing up and replaying. This might not happen with other computers. Driving the Element from the same computer in pure analog mode eliminated this issue. By “pure analog mode” I mean: instead of feeding the Element’s DAC from USB, I installed a high quality sound card and fed the Element the analog unbalanced line level output. This bypasses the Element’s DAC entirely.

I have one minor quibble with the Element – the build quality is good, but not quite excellent. The connectors aren’t the rock solid Neutrik et.al. you get on true audiophile amps, and doesn’t give the satisfying thunk those provide when you connect & disconnect. It has me plugging in the headphones & other connectors with care. The volume knob is very smooth and satisfying to use (and it’s a top quality Alps pot), but it has a bit of give when you push gently on it and the instructions say not to lift the amp by the volume knob – despite the amp being small & light. Overall, the Element is well built yet not the solid brick military build quality of top-tier professional and audiophile equipment. I suppose JDS had to find cost savings somewhere, and they seem to have made the right choices. It does have a solid warranty you can use if something breaks or flakes out on you.

Overall, thumbs-up for the JDS Labs Element. It is a complete DAC+amp, semi-portable by turning any computer into an audio source, with enough clean power to drive just about any headphone on the planet. It has excellent sound quality, though just a bit short of absolute reference quality. It’s fantastic the level of engineering, sound quality, and output power you get for the price.

Background: JDS Labs Element & Audeze LCD-2 2016

Background

I spend a lot of time at work and wanted a reference quality headphone rig to match my home system. Technology is constantly improving, reducing the price of reference quality audio every year. I still love my LCD-2 headphones, so they were at the top of my list yet I was open to trying any new headphones released since then. I wasn’t going to get another Oppo HA-1, which I used in my home system. It’s too bulky and has way more features than I need, and at work I use the computer as an audio source. I have a great computer audio system at home too, using a Juli@ sound card and Corda Jazz amp. I’d consider getting another just like it, but first wanted to check out what alternatives might have recently appeared.

If you’re using a computer as the audio source, you need two things:

  • A high quality D-A converter to get a line level analog signal.
  • A high quality headphone amp to amplify that signal and drive headphones.

A sound card does the first – but it’s not portable and only works with desktops (not laptops). Now, all computers can stream audio files out a USB port to an external DAC. This is portable and works with any computer – desktop or laptop. With the right configuration (adaptive or async), the external DAC clocks the bits and jitter is not an issue.

Given my preference for no-nonsense engineering over audiophile mystique, I quickly found JDS Labs, aka some guys in Illinois building well-engineered and built headphone audio gear on a budget. They started by producing a little amp called the O2, an open source design released into the wild by NwAvGuy. Prior to JDS, this was only available as a kit, and lots of headphone audiophiles don’t have the skills to build it. Perhaps they should – no Jedi’s training is complete until he builds his own light sabre – but that’s a different subject.

A few years ago, JDS started building their own designs, which took the O2 to another level in performance and higher power output enabling them to be used with a wider variety of inefficient power hungry headphones like the HiFi Man HE-6. Yet even JDS’s new gear was built to solid engineering specifications without any audiophile nonsense and reasonably priced.

Long story short, I got a second pair of LCD-2 headphones and a JDS Element to drive them, which is a headphone amp combined with a USB DAC. I compared this amp to my HA-1 and Corda Jazz, which is stiff competition.

I posted my reviews of the Element and 2016 LCD-2 separately.

HRTF

HRTF is Head Related Transfer Function. It describes how you perceive sound. Every person perceives sound differently because the individual shape of your head, ears, nasal & mouth cavity, etc. all affect how the sound reaches your ears. In short: different people listening to the same thing, hear it differently.

What most HRTFs have in common is the range from 2 – 5 kHz is amplified by 15 dB or more. The ear’s resonance is typically +17 dB at 2.7 kHz. That is a huge non-linearity. Here is a typical HRTF curve from Tyll Herstens at Inner Fidelity.

Another way to think about this: Suppose you’re standing at the seashore listening to waves crashing on the beach. That sound is similar to white noise: it has roughly equal energy across a wide frequency range. The sound you actually perceive, however, is 10 – 20 dB louder in the 2 -5 kHz range because those frequencies were amplified (or frequencies outside that range attenuated) by your head, ears, ear canals before it hit your eardrums.

You can easily test how the size & shape of your head & ears affects sound. While listening to music on speakers, gently push your ears forward or open your mouth really wide. The sound changes. And that only gives a small taste of what the real differences are – imagine how much more different it might be if you could change the size & shape of your head, ears, etc.! That different sound you hear would be what another person hears normally.

The astute reader will wonder – if this variation is due to individual variance in body size & shape, how can it be measured? The answer is simple. Take 2 tiny microphones small enough to fit inside your ear canal. Position them in the open air and use them to record sound. Now build a fake life-size human head using materials that approximate the density & reflectivity of human tissue and skin, and insert these same mics deep into the ear canals, facing outward. Now measure the same sound again. The difference between the two recordings is the HRTF of your dummy head.

Every person has an individual HRTF and the variance from person to person is significant. Since headphones bypass the HRTF, in order to sound natural they must have a frequency response that matches the HRTF. Put differently, a headphone with flat frequency response would sound quite dull, down 15+ db in the 2 – 5 kHz range.

This doesn’t apply to loudspeakers. If a speaker has objectively flat FR, every person will perceive that however they perceive natural sounds. Speakers don’t have to reproduce the HRTF because the sound comes from a distant source and your HRTF transforms it when it hits your body. Headphones play sounds directly into your ears, bypassing your body, head and HRTF.

This means there is an absolute reference FR for speakers: perfectly flat. But there is no absolute reference FR for headphones. A headphone has to mimic the HRTF which is different for every person. The best a well-engineered headphone can do is mimic the most common or average HRTF across the population. Each individual will be a little different.

Thus, different people will disagree on what headphone has the most natural FR reproducing sounds most realistically. For example, the Sennheiser HD-800 has a big response rise around 5 – 7 kHz. For me personally, it’s artificially bright, almost skull-jarring. But for others it may sound natural. At the opposite end of the spectrum, the Audeze LCD-2 has a dip from 2 – 9 kHz (its raw response has a rise, but it rises a bit less than the typical HRTF does). For me personally, it sounds natural and realistic. My HRTF probably lifts this frequency range less than average. But for others this headphone sounds dull.

Good IEMs (In-Ear Monitors) aka Earbuds

Most phones have very good audio output quality via their analog headphone jack <note to self: resist urge to crack iPhone 7 joke…> if you can find earbuds that sound good. Yet that’s a big if. Most earbuds sound like crap. Of the few that sound good, some have impedance or efficiency that don’t match well to a phone. Also, while phone audio output is often very good, that does not mean excellent or reference quality, so don’t go overboard and waste money on really expensive IEMs.

I listen to mostly natural acoustic music and I’m picky about sound. The best really good IEM I’ve found is the Vsonic GR07. They cost about $100 and sound really good. To my ears, they’re comparable to a pair of full-size HD-600. They have flat, neutral response that is neither warm nor bright, but just right. The treble is smooth with good detail. Due to a phone’s audio output limitations, even with uncompressed FLAC files the extreme high frequencies are rolled off and there’s less “air”, slightly less crisp transient response.  It sounds very good, even great, but not excellent or reference quality. The GR07 is about the best quality it’s worth paying for given the limitations of the source.

The best cheap IEM I’ve found is the Vsonic VSD1S. They cost about $35, have the same high quality construction and 90% as good sound as the GR07. Comparatively, the VSD1S has a slight midrange recess, not quite as smooth or extended treble. Overall, they still have a nice neutral sound despite have a touch more “V” shaped response curve. They’re good enough to listen to for hours enjoyably without fatigue, better than most other good IEMs, but just not quite as refined as the GR-07.

A Cheap Audiophile Headphone System

Here’s a cheap audiophile quality sound system:

That’s it. Connect the Juli@ unbalanced analog outputs to the amp’s inputs. Play your CDs, DVDs, whatever on the computer. Use whatever headphones you want.

Total cost: $510 = $170 for the card, $340 for the amp. Plus the headphones. You can get some vintage Sennheiser HD-580 or HD-600 on eBay for a couple hundred bucks. Or you can go all-in with a really nice set of headphones like the Audeze LCD. The Corda Jazz has a smooth sound, detailed and sweet yet neutral, with enough power to  drive almost any headphone on the planet.

I use this as a secondary system to drive my Audeze LCD-2F when my reference system is unavailable. It is amazing – 95% as good as the reference system. Extreme treble and large ensemble complex music is not quite as refined, but that’s just picking nits because it sounds damn good.

Years ago when I was in college I would have climbed a mountain of broken glass for sound like this, especially at this price.

Note: you can get an audio system like this even cheaper from JDS Labs. Get a single DAC+Amp for $300, so you don’t need the sound card. Just stream the bits from the USB port of any computer into the DAC. JDS Labs is the American version of Jan Meier’s Corda in Germany: a few guys in Illinois who are good electrical engineers and take a non-nonsense approach to building audiophile quality gear without audiophile prices or bullshit.

The Fantastic Audeze LCD-X

A few years ago I found the best headphones I’ve ever heard, the Audeze LCD-2. These are the 2014 Fazor version. A while later I made them even better with a subtle parametric EQ. That may sound like sacrilege to some audiophiles, but it works for me. The LCD-2 has  enhanced my late-night music listening and I still enjoy and use them regularly.

Since then, Audeze came out with another headphone: the LCD-X. It is designed to have a more neutral (flatter) frequency response and faster/cleaner transient response. Both of these claims are substantiated by measurements. But how do they sound? I wanted to find out. Audeze had a sale so I ordered a pair to get a listen.

Dimensionally, the X are exactly the same as my 2, or so close I couldn’t tell the difference. They’re black and made of metal, where the 2 are wood. The X are a bit heavier, but I didn’t feel the difference. Clamping force, fit, they felt exactly the same on my head.

I ran the comparison through my Behringer DEQ2496. More precisely, CDs played on my Oppo BDP-83, toslink to DEQ2496, toslink to Oppo HA-1, balanced headphone out. The DEQ2496 enabled me to level match within 0.5 dB, keeping the signal otherwise unchanged, or apply EQ as mentioned below. This doesn’t use the DEQ2496’s DA or AD converters; it operates in pure digital mode. Subjectively, I found the X to be 8.5 dB louder than the 2, so used this to equalize the levels.

Tech note: According to specs the X is about 11 dB louder than the 2 at the same volume setting. According to Audeze specs, the X makes 103 dB with 1 mW of power and has a 20 ohm impedance. Since it’s planar magnetic, the impedance is flat vs. frequency. That means 0.1414 V (141 mV) will make 103 dB, so 0.0317 V (32 mV) will make 90 dB. The voltage sensitivity of the LCD-2 is 0.114 V @ 1 kHz @ 90 dB. So we have 20*log(0.141/0.032) = 12.9 dB. My subjective impression was slightly different. Attenuated by 13 dB, the X was quieter than the 2; I used 8.5 dB.

First I did the fair comparison: head to head, no EQ. Here it was no contest: the X was easy to differentiate, and overall better sound:

  • X has more upper mid – no dip like the 2
  • X bass is slightly (about 2dB) quieter, but just as flat and deep
  • X has slightly better bass clarity
  • X has more linear and extended treble
  • X sounds “cool”, not “warm” like the LCD-2
  • Detail: X is on stage with the musicians, 2 is in the 5th row back
  • The X has more detail than reality; the 2 has less than reality; neither is perfect but the X is closer

However, I don’t listen to my 2s straight. I apply a parametric EQ: +3 dB @ 4600 Hz, Q=0.67 (3 dB / octave, 2 octaves wide). This counteracts the 2’s softness in the upper mids and lower treble, giving it a more neutral response curve and a bit more detail as if you’re sitting a few rows closer to the stage.

So next I did the realistic comparison: how I would actually listen to them: X raw, versus 2 with the above EQ:

  • They sound almost the same
  • X emphasizes the overtones, but still has the core sound
  • 2 favors the core sound, but still has the overtones
  • X is slightly more clear, yet less realistic voicing on some recordings
  • 2 has more realistic voicing on most recordings, yet slightly less clear
  • 2 is on the warm side of reality, X is on the cool side
  • Overall, which sounds better depends on the recording

Here it was a much harder decision. I also compared them to my speakers. They were about equally close to that sound, yet approaching it from opposite sides. These are both excellent headphones and I could be happy with either. They wipe the floor with any conventional dynamic headphone I have ever heard. If I didn’t already own the 2, or if I didn’t have a digital parametric EQ, I would pick the X. But I do already own the 2, and with the parametric EQ they are just as good as the X. I listen mostly to acoustic music and the 2’s realistic voicing is more important to me than the X’s extra 1% of detail. So why change anything?

I kept my LCD-2F and returned the LCD-X thanks to Audeze’s excellent service which includes a 30 day trial period. It was a fun experiment and satisfied my curiosity. While I kept my LCD-2F, I can heartily recommend the LCD-X to anyone who wants a fantastic set of headphones with dynamic and detailed yet realistic sound.