Etymotic ER4SR

Etymotic Research, Inc. has some impressive staying power within the head-fi industry. In fact, my very first Head-Fi meet happened at their headquarters in Elk Grove. Tyll Hertsens (then of HeadRoom, now of InnerFidelity) was busy crisscrossing the US with his ‘Traveling World of Headphones’ set up – basically a veritable buttload of high-end headphone gear packed up in the back of a van. I bought my first pair of Ety’s that year, reaching what was then the pinnacle of IEM’s. A few years later, I lost them in a move and basically made-do in the meantime with my first pair of ‘audiophile’ headphones (the Alessandro MS-1’s) until the headphone bug bit me again and I scored a newer, but still used, pair off eBay.

I broke them not too long afterwards while on a business trip. As Homer Simpson would so eloquently put it, D’oh!

They do offer a trade-in program for numbskulls like me who, at the time, had a more cavalier attitude towards protecting precious head-fi gear while on a flight. So I took advantage of that and got a brand new pair. What happened to those? Well, I sold them to a local audiophile friend to fund the purchase of the Audeze LCD-XC’s.

Now, even with the fancy protective case, the LCD-XC’s aren’t what I’d call portable. Once again, with more travel looming on the horizon, I found myself wanting another pair of Ety’s and promptly found another pair for sale on Head-Fi. This time they turned out to be the ER4-P’s. Now, if you’re not familiar with the Etymotic lineup, the ER4-P’s are the lower impedance version of the ER4-S, with a concomitant slight bass boost. It does, however, come with a P to S adapter, basically bringing up the total nominal impedance and frequency response back in line with the ER4-S.

In keeping with my longstanding tradition, I lost that pair by leaving them in the seat pocket in front of me while on the actual trip.

Which is how I came to be the owner of a gently used pair of ER4SR’s, the recently updated version of the ER4-S. It uses a new balanced armature driver with a lower 45 ohm nominal impedance while simultaneously boosting sensitivity 8 dB over the ER4-S so it can be easily driven from your portable device. As an added bonus, the bodies housing the drivers are milled from aluminum, which means that breaking them is pretty much a thing of the past.

Luckily, the local audiophile friend still had my ER4-S’s and loaned them out to me for a short comparison. I listened primarily to two tracks – Rilo Kiley’s “Silver Lining” from Under the Blacklight and Tegan and Sara’s “I Was A Fool” from their second to last album, Heartthrob. I thought that for the most part the previous model and the newer one shared the same overall tonal balance and spatial presentation. However, the ER4SR’s sounded a bit smoother in the presence region and I did end up preferring it over the older model. Otherwise, I’d be hard-pressed to tell them apart.

In comparison to other headphones I have on hand, the LCD-XC’s sound a touch more transparent, though with a slightly brighter sound. However, the ER4SR’s can’t stand up to the hefty bottom octaves of the XC’s. The Sennheiser HD 800’s sound warmer, with fleshier vocals that seem to be a result of a slightly more prominent lower midrange / upper bass.

What’s most remarkable is that I find the ER4SR’s to be most like my loudspeakers in terms of the midrange and treble out of all the headphones I own. In other words, after an extended listening session with the Ety’s I can transition to loudspeaker listening after a very short adjustment period. The HD 800’s are fairly close in this regard, the LCD-XC’s less so than either.

The Etymotic ER4SR are certainly a worthy headphone. Reasonably priced with excellent performance, they’re the kind of gear that you can hold on to forever. Unless you’re me, of course.

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Corners of the audio mind, part two

Digital audio is still a mystical concept, I think, to most audiophiles. I know it is to me. Yet, if you put in the effort and do some digging on the internet you can turn up some priceless nuggets of information. Hopefully some of the following links will be useful and leave you with a deeper and more nuanced understanding of all the technologies involved. It also made me marvel at all the hard work and engineering that went into creating devices used for the sole purpose of recreating music.

But first, let’s start off with the most basic of things. Is the signal coming out of a DAC really a staircase? What is dither and what is it used for? Do more bits equal more resolution? Chris “Monty” Montgomery explains it all in Xiph.org’s wonderfully practical video Digital Show and Tell. Yes, it’s a few years old, but a recent email from Benchmark Media brought it back to mind recently and I think you’ll find it enlightening as well as entertaining.

If you really want to get into the weeds of digital conversion of analog signals, then what better way to start than with Analog Devices’ Data Conversion handbook? This volume spans nearly every topic an audiophile would be interested in – from the history behind digital conversion to brief overviews of various ADC/DAC architectures and application notes. If you’re ready for a deep dive, check out their equally excellent series of tutorials that provide even more detail on digital systems and digital converter architectures.

Putting all that information together helps you appreciate articles like this excellent look inside the Sabre ES9018 DAC from Benchmark Media even more.

Now for some food for thought. Chris Montgomery also authored an interesting article on ‘high-resolution’ audio, titled “24/192 Music Downloads …and why they make no sense”. I’m sure some of you probably have already read it… and relegated it to the dustbin since you’re positive you can hear a difference. But to illustrate the point of that article better, first have a look and listen to Audiocheck.net’s Dynamic Range, Dither, and Noiseshaping page. Then try out the 16-bit vs. 8-bit blind test. Your reaction might range from surprise to shock to amusement.

The Right Stuff

Chalk one up for progress.

I’ve been a long time fan of the movie, The Right Stuff. I love its portrayal of the US Air Force test pilots and the astronauts of the budding space program. A major contributor to the overall feel of the movie is the soaring score by Bill Conti. In the intervening years, I’ve always wondered why I could never find a decent recording of the soundtrack.

Thanks to HDtracks, now I know why.

When released, the film performed poorly at the box office and the Ladd Company pulled the plans to release a soundtrack. Over time, the master tapes were lost. A double CD with select tracks from The Right Stuff as well as the television miniseries North and South, was produced at Conti’s own expense. However, something like that wouldn’t really satisfy a die-hard fan… like me.

Lo and behold, however, one night I was browsing the soundtrack section of HDtracks and came across The Right Stuff. This was the album that supposed to be released with the movie, resurrected from the dead by the composer himself. (He had kept the tapes produced during the mixing sessions.)

Content-wise, it’s all I could’ve hoped for. Sonically, the release has a few warts – you can clearly hear edits on some tracks and the stirring finale, “Yeager’s Triumph” is decidedly panned off-center.

Despite all that, I love every minute of it. Ok, maybe not the last track with its (now) hilariously outdated 80’s aesthetic, but the rest of it is pure gold.

The Art of Listening

I just came across this excellent documentary on the creative process behind bringing you the music that you enjoy. It covers the perspectives of the instrument makers to the songwriters and artists to the audio engineers. It’s a wonderful film and to do it justice, please listen to it on your big rig, whether it’s speaker or headphone based. I’m sure you’ll enjoy it. Oh – and share with your non-audiophile friends too! Maybe you’ll make one or two a convert…

New Border Patrol DAC, Ayre QB-9 double-rate DSD update

Two bits of news:

First, I received an email the other day from Gary Dews, chief designer and sole proprietor of Border Patrol, about a new DAC. I heard this particular unit in prototype form at the last Capital AudioFest and it sounded absolutely spectacular, belying its humble bamboo exterior. Now decked out in a copper metal chassis, it still sports the vintage Philips TDA 1543 to convert the incoming bits using a R-2R resistor ladder. The outputs are coupled directly to the outside world using boutique capacitors. No oversampling or analog brick wall filters need apply. However, the real heart of the DAC might just be the hybrid tube / solid state power supply. Two versions are available, standard and SE. According to Dews, the SE version “has a better power supply featuring BorderPatrol’s low distortion twin transformer system as used in the large BorderPatrol EXS amplifier PSU’s. It uses a Cerafine power supply capacitor instead of Panasonic and has Uptone Audio film and foil signal capacitors rather than Clarity Cap metalized polypropylene.” Pricing starts at $899 for the standard version with either a USB or SPDIF interface (a unit with both inputs can be built at higher cost). More information can be found here.

Second, I noticed in the Computer Audiophile forums that Ayre is offering an update to the QB-9 DSD – even though the DAC is no longer in production. It’s basically new firmware that enables you to play back double-rate DSD as well as PCM files with sampling rates up to 352.8 kHz. No changes to the analog signal path are made. The price for the update is set at $200. The Computer Audiophile post can be found by clicking on this link.

Corners of the audio mind

The internet is wonderful, isn’t it? Yet, I find myself visiting the same old audio web sites, online publications, and forums. So here’s a few links to some sites that you might not have come across. They’re chock full of information and, best of all, largely devoid of puffery and marketing.

The first is Art Ludwig’s Sound Page. I came across the site when I wanted to know more about the audibility of distortion in solid state and tube amps. His personal experiments, outlined in this section, seem to be a lot more rigorously designed than the kind your garden variety audiophile (including me) would employ. The rest of the website is full of useful insights and make for excellent reading. I’m sure that wherever you are in your audiophile journey, you’ll find something you can learn from Art’s site.

While the Sound Page contains a short tutorial on digital audio, I think the best FREE online book on the subject has to be the The Scientist’s and Engineer’s Guide to DSPEven if you have an electrical engineering degree, you still might want to give it a quick read and bookmark it. The book is written in a straightforward style with practical examples which illustrate the concepts quite effectively. Another rich resource for techniques in processing digital signals is the dspGuru website. It’s aimed towards practitioners, but if the online guide to DSP proves too boring (or if you’ve finished it), this might be a good place to enhance your understanding.

Finally, given the recent flap over Stereophile’s Facebook comments on head-fi’s DAC du jour, the Schiit Yggdrasil, caught some by surprise, I wasn’t terribly shocked. That’s because I came across this blog post on diyAudio months before the review posted to the newsstands and the interwebs. The blogger offers a fairly balanced critique of the wisdom of using an industrial DAC chip for an audio application, and pokes a few holes in the marketing behind Schiit’s custom ‘closed-form’ oversampling digital filter that the DAC employs.

Well, that’s it for now. If you’ve got links to sites and articles that have proved enlightening to you, feel free to share them. Hope to catch you on the flip side!

ampsandsound Mogwai headphone amp – a review

It seems that ampsandsound‘s Justin Weber is a fan of vintage equipment – Klipschorns, single-ended tube amps – and now wants to spread a somewhat modernized vision to a new generation of audiophiles. Although their offerings include designs based on tubed output stages, the power supplies are solid-state and point-to-point wiring is eschewed for PCB’s. The subject of this review is their relatively affordable headphone and integrated amp, the single-ended Mogwai.

Description

The Mogwai has a classic look about it that’s not too far removed from the amps you’ll find from Border Patrol or Bottlehead’s DIY kits. The sides of the chassis are made of wood panels with the bottom and top panels in steel. The labeling on the top panel seems to be laser etched and stands out clearly. All controls and connections are made from the top panel: the volume knob and power switch are located along the front with a pair of single-ended inputs, headphone output socket, speaker output binding posts, and power inlet taking up space in the rear. Tube sockets aren’t labeled but the input tube socket is oriented differently from the output sockets to prevent folks from accidentally inserting the wrong tube. Four stout rubber feet keep the amp from sliding around.

You can roll the output tubes to the 6L6GC, EL34, KT66, KT77, KT88, 6550, or KT90 without batting an eyelash. The input tube is limited to the 6SL7 and its equivalents. The tube complement for this review included a pair of Apex-matched JJ 6CA7’s and a NOS RCA 6SL7GT. The output tubes are wired in triode mode.

Headphones can range in impedance from 32 – 300 ohms but speakers are limited to 8 ohms nominal. The manual states that baseline specs for loudspeaker listening is 87 dB sensitivity and an impedance that doesn’t dip to 4 ohms. Unfortunately, that meant that hooking the Mogwai up to my Vandersteen 3A Signatures was out of the question.

Operation

The amp is straightforward to connect and turn on. It’s also powerful. Even when used with the Sennheiser HD 600’s and listening to SACD’s on my Ayre C-5xeMP (which outputs a signal that’s 6 dB lower than with PCM material), I never reached 9 o’clock on the volume knob. The Mogwai is a beast, at least for the headphones I had on hand.

At times, there were some audible pings from the output tubes as the amp warmed up. I also found the Mogwai somewhat susceptible to microphonics – I could hear light tapping on the amp’s chassis through the headphones and it even amplified light knocking from my desk. There was also a very low-level intermittent noise in the right channel. Justin assured me that these were all due to the miles that the amp has covered in its travels and that normal production samples would be quiet.

Sound

I listened to the Mogwai using my Audeze LCD-XC’s and the aforementioned Sennheiser HD 600’s. Through both sets of cans, the amp exhibited eminent control over the audible frequency spectrum. This was particularly noticeable in the bottom octaves where it might have been a little too iron-fisted. Images possessed an athletic quality to them: well-defined and taut with a piquant tonal balance. The Mogwai sounded clean and the midrange was finely textured.

As I listened to track after track, clarity and resolution were words that kept coming to mind. On tracks like The National’s “Demons” (CD, 4AD, CAD3315CD), Tegan and Sara’s “White Knuckles” (24/96 FLAC, HDTracks), and The Yeah Yeah Yeah’s “Little Shadow” (CD, Interscope, B0012735-02), vocal and instrumental textures were readily apparent and drum kits were tight. Distorted guitars sounded, well, distorted. Images were appropriately dense, though the bottom octaves lacked some heft. The Mogwai seemed to hit its stride on classic rock. On “Done Somebody Wrong” from The Allman Brothers’ The Fillmore Concerts (CD, Polydor, 314 517 294-2), Doucette’s harmonica took on a slightly wailing quality. Vocals, percussion, and guitar all telegraphed clean and clear across the ages. The Mogwai did an equally fine job on Cream’s “White Room” from The Very Best of Cream (CD, Polydor, 31452 3752-2). Its incisive approach to Baker’s drumming and Clapton’s wah-wah’d guitar riffs showcased its low-level resolution chops.

Lateral spatial resolution was stable and the soundscape seemed to be projected outward. Images never wandered. During complex passages in classical material such as the finale of Schumann’s Piano Concerto (CD, Sony, SK 64577) or Saint-Saëns Organ Symphony (SACD, Telarc, SACD-60634), the amp remained poised and firmly in control. Yet a convincing portrayal of depth seemed to elude the Mogwai. Performers and instruments seemed to generally exist on the same plane throughout. Images were focused, but I sometimes got the sense that they tended to be a cardboard cutout of the real thing.

Transients never lacked snap and it commanded dynamics of the micro and macro variety. On the Cold War Kids’ “Go Quietly” (CD, Downtown, DWT70397), the Mogwai captured the sharp report of every snare hit. The same went for Rilo Kiley’s “Silver Lining” (CD, Warner, 189372-2) – the drum kit sounded tight, though the kick drum and bass line were a bit lower level than I’m used to. On acoustic fare such as “Al Vaivén de mi Carreta” from AfroCubism (CD, Nonesuch, 525993-2), guitar sounded clean from the initial pick through the subsequent decay of the string tone. Background percussion possessed a tactile quality that served the sinuous rhythm of the song. On Holst’s “Jupiter” (CD, London, 289 560 606-2) the initial crescendo was intense and the finale was equally stirring.

I felt the Mogwai was within a whisker of ultimate timbral realism and naturalness. Perhaps part of the cause could be traced to the somewhat dampened bass response. That might have robbed the sound of a bit of warmth, lending a slightly more forward nature to the presentation. Whatever the case, massed strings sounded just a touch dry and I missed a small degree of airiness from symphonic works. The instrumental solos in “I’m Old Fashioned” from Blue Train (24/192 FLAC, HDTracks) seemed to lack a smidge of vitality and glow. It took my mind a bit more effort to suspend disbelief and simply flow with the music.

Comparisons

I normally switch between two amps when listening to cans: the Donald North Audio (DNA) Sonett 2 and the HeadAmp GS-1 with Dynalo+ modules. The former is an all-tube SET topology utilizing a 5AR4 rectifier and a pair of 6H30’s with their twin triode sections paralleled for more power output. The latter is a solid-state design with a venerable history.

The Sonett 2 added some heft back to the lower registers along with a sensible dollop of warmth to vocal and instrumental timbres. To my ears, it sounded more organic and better balanced next to the Mogwai, though its sound field was less intense with a mid-hall perspective – even when volume levels were matched. The DNA amp also sounded a touch smoother through the midrange and treble at the expense of some texture and images possessed more dimension.

The GS-1 split the difference between the Sonett 2 and the Mogwai. It too was a little more even in its frequency response and posted slightly more natural sounding images with a similar perspective to the Sonett. I also felt it projected a more dimensional and layered soundscape than the Mogwai or the Sonett 2, but didn’t quite reach the realistic timbre of the latter nor the detailed and textured sound of the former. Like the DNA amp, the GS-1 offered up more bass quantity without sacrificing quality in the process.

Conclusion

The Mogwai’s vibrant nature and generally excellent command over the frequency spectrum is ripe for some serious system matching exercises. It truly was a shame that I didn’t have loudspeakers with the right specifications on hand for pairing with the Mogwai. Music lovers looking for an amp with an intense sound and a laser-like focus take note: this amp may be the perfect match for you.

 

Associated Equipment

Headphones – Audeze LCD-XC (2016 drivers), Sennheiser HD 600

Sources – Ayre Acoustics C-5xeMP, Ayre Acoustics QB-9 DSD

Amplification – Donald North Audio Sonett 2, HeadAmp GS-1 w/ Dynalo+ modules

Cabling – Blue Jeans Cable LC-1 and 1800F interconnects

Power – Bryston BIT-15, ZeroSurge 8R15W-I

Volume levels were matched using pink noise from Audiocheck.net using a Radio Shack analog SPL meter (model 33-4050) on C weighting, slow response.