Hi Guys,

Today we are talking about a very interesting headphone from Hong Kong, made by the company ES-Lab. ES Lab started out repairing old Stax headphones, and doing DIY work, eventually leading to the release of their ES1a headphone, their take on the Stax Sigma, and most recently their recreation of Sony’s legendary R10. The ES1a is styled after the original Stax Omega from the 1990s, but all in black, with gold screws. Although the looks are very similar, the sound between the original Omega and the ES1a is supposedly somewhat different, although I have never heard an original Omega to do a direct comparison. The ES1a retails for right around $1750USD which for the performance it provides, is honestly quite compelling in todays headphone market, especially in term of electrostatic headphones. 

The vast majority of this review was done with the HeadAmp BHSE, a KGSSHV Carbon, and an iFi Pro iDSD DAC as supporting gear. 

In terms of level, the bass of the ES1a in its stock tuning is not enough for my personal preferences. I think this may partly be due to the very loose clamp force the headband provides. I do have quite a large head, and even I found it to be a very loose fitting headphone. When I very lightly provided a more secure seal, the bass level did rise slightly, and seemed to also be a bit punchier. If you are open to EQ’ing up the bass via a simple low shelf, then that also solves the problem easily. There is about the same amount of bass as a stock SR009 I find, and certainly a bit less than the SR007mk2. With that being said, after a small EQ boost, the bass is entirely satisfying, and has a somewhat rounded off leading edge. There is slightly more impact than the 009 and about the same amount as the 007. Overall, I think people’s perception of the bass may differ depending on the clamp level they experience from the headphones, and the seal they are able to get with their head shape and the ear pads , but the overall bass quality is actually very good and can be tweaked via EQ to the users preference. Once thing to note is that it helps to have a powerful amplifier, as these headphones are quite hard to drive, especially if you take negative gain compensation on the EQ if you are boosting the low end. 

The mids of the ES1a make them a less thick and warm sounding headphone than the SR007mk2, yet less cold and thin than the SR009. They really do split the difference between the two quite nicely. There is a slight amount of warmth and “sweetness” to the mids that I really enjoyed. Around about 1khz there is a bit of a bump I think, and this seems to be an electrostatic thing, as a lot of examples I’ve tried have this bump. Honestly, I could have thoroughly enjoyed these without any tweaking via EQ, but I wouldn’t be surprised if some people preferred a little dip via EQ at around about 1khz. I never found the ES1a to sound somewhat nasal and honky due to the 1khz range where on some other headphones that certainly can happen. Apart from that, there really isn’t much I found about the midrange of the ES1a to be offensive at all. I really liked how these headphones worked with all sorts of music styles and were never overly shouty or harsh in the upper mids. 

The treble performance of the ES1a is where it excelled for me personally. There is a bit more energy in the highs than the SR007mk2 but less than the SR009, again splitting the difference between the two very well. I didn’t find the treble at all tizzy or sharp, bright or harsh. Yet at the same time it never sounded dull or as if it was smoothing over details and going towards being a darker tuning. Overall, the treble response of the ES1a is probably the best aspect of its overall tuning and is incredibly pleasing and addictive. In a way, it reminds me of the treble of the Hifiman Susvara. It’s not as finely detailed as the Susvara, but in in terms of its overall character and tuning, there were similarities to my ears. 

In terms of technical performance, the ES1a is quite impressive, especially in terms of their price/performance ratio. Their overall detail level seemed to be quite similar to the 007mk2 from Stax, but the overall sound image was much larger than both the SR007mk2 and the SR009. The soundstage was wider, taller, and larger front to back than both of the Stax offerings. I suppose this may have to do with their pad shape and tuning. Microdetail was also quite well done for an electrostatic headphone in this price range. I did find that they were again similar to the SR007mk2 in terms of their dynamic performance, both micro and macro. Nothing groundbreaking, but again, very good for the price. 

The ES1a is about on par with the SR007mk2 in terms of how hard they are to drive, meaning they seem to love power, and will do best with a good powerful electrostatic amp behind them. 

In terms of build quality, the ES1a seems entirely acceptable and actually feels more substantial than the SR007mk2 The construction materials are a mixture of metal and plastic, and although they do weigh quite a bit, they never felt like a burden to wear (as some Audezes and similar can feel over time.) I would personally like slightly more clamp force, simply to make the ES1a feel a bit more secure and snug on the head, and I also think it might help their low end performance slightly. The cable is very similar to the ribbon cable you get with Stax headphones, and seems well built, and does the job nicely. In terms of aesthetics, I think they look awesome. They take the shape and design language of the original Stax Omega and update with a sleek all black look, with slight gold accents from the screws. It works for me, and I think they are one of the better looking headphones I have come across. 

Overall, the ES1a is a great pair of headphones, especially if you tend to favour electrostatic headphones and what they do well. Although the low end in its stock tuning isn’t really anything groundbreaking, the mid and treble tuning are very well done, and the detail and technical performance is very good for their asking price. If you don’t mind boosting the low end a little with a bit of EQ, then I could see these being great all rounders. If someone were looking into buying a Stax headphone at SR007/009 type pricing, but can’t figure out which they would prefer, or just want a better all rounder whilst also saving some money, I would seriously recommend giving the ES1a a try. They seem to split the difference between the two former flagships from Stax, and also look better (in my opinion) whilst doing so.