I recently reviewed the Sivga Robin closed-back headphones. You don’t see the Sivga name along-side the usual brands in the hi-fi magazines, but they are not new to the game. They’ve been producing beautiful hand-crafted headphones for years, and produce drivers for the OEM market too. It’s finally time to check out the more upmarket model from sister company Sendy Audio in the form of the Aiva, a gorgeous pair of open-backed, planar magnetic headphones at a bargain price typical of the Far East.
A member of the company’s ‘Black Beauty’ range, the Aiva is an over-ear design with Zebrawood ear cups and hard anodised aluminium fitments. They are handmade in small quantities and every part is custom-designed right down to each individual screw.
The ear cups are produced in six stages; wood selection, rough cutting, CNC carving, polishing, repeat finishing and air drying. Manufacturing products in this way is labour-intensive and cannot be automated. But the time and effort pay off in a finish and individuality that looks and feels every bit as exquisite as it sounds. Wood is an obvious choice for a headphone enclosure too as most loudspeaker boxes are made of wood, as are most instruments. Traditional headphone ear cups made from plastic or aluminium are easier to manufacture in large quantities, but the sonic and visual superiority of wood is hard to dispute. It’s also more environmentally friendly in terms of sustainability, production, waste and recycling.
Those enclosures contain a custom planar-magnetic driver with a 3 micron diaphragm (a human hair is more than 23 times as thick) in a high-stiffness material. Unlike a traditional moving coil dynamic driver, which is very much like a miniaturised loudspeaker, the planar-magnetic driver is an electromagnetic induction driver but is a hybrid dynamic and electrostatic driver. If you’re interested, there is an excellent article on the five different types of transducers found in headphones Here and one specifically covering planar drivers Here.
Embedded into the diaphragm is a serpentine conductor – a bit like a flattened, deformed coil – which, when fed a signal, causes a varying magnetic field around the diaphragm. When this interacts with the array of permanent magnets sandwiching the driver, the diaphragm moves relative to the audio signal. The drivers are designed with a gap between the diaphragm and the magnet arrays to allow air and sound to escape, and efficiency is achieved by positioning the magnets to apply an even field of magnetic flux at the conductor area of the diaphragm with a high flux density. This is known as an isodynamic magnetic field.
The Aiva’s driver is 97 mm x 76 mm in size and Sivga quote a 20Hz – 40kHz frequency response. I asked if there were any reference figures for linearity and was supplied the below graph:
The graph indicates a response fairly flat from around 23-600Hz, with a prominent dip in the midrange before a treble rise after 10kHz. I’m not sure how the measurements were taken, nor do I know what the ambient environment was which would be a contributing factor in any measurement given the open-backed design.
Impedance is rated at 32Ω (+/-15%) and sensitivity a moderate 98dB (+/-3dB) per 1MW so some portable devices and any good amplifier will drive them with relative ease. Naturally the best results will be realised using a dedicated amplifier, particularly one with balanced connections, especially at higher listening levels where portable devices and low-powered amplifiers may be driven to clipping.
The Aiva’s are fully balanced and come with a 1.6 m cable terminated in a 4.4 mm balanced connector. You also get a 4.4 mm balanced to 3.5 mm stereo unbalanced adapter cable in the box, though no quarter-inch adapter is supplied nor an XLR adapter. The Aiva follows standard wiring, so any 4-pin XLR headphone adapter will work just fine. I would like to see a longer (3 metre) cable included in the box, as the 1.6 m cable is on the short side when the amp is positioned in a rack at an average distance from your listening seat.
One small niggle is the lack of tactile markings on the cable or the headphones to indicate left / right polarity. There are visual markings but they’re no good for those of us who can’t see them. The markings on the headphones themselves, engraved into the pivot points, can be felt with a nail, but not so the cable. A few raised dots to indicate the left earcup, and a tactile ring around the left plug, would be good to see in a future revision.
The Aiva packaging is smart yet simple, with Aiva branding and some specs printed on an otherwise plain looking box. One welcome inclusion is a beautifully made sculpted hard carrying case with smooth material lining and real leather zip and carry strap. The case is in a soft-textured material with a slightly spongy feel which provides excellent protection for the headphones inside. It even has round metal feet so it can stand upright on a display shelf. A drawstring Hemp cloth bag holds the included cables.
The construction is meticulous from the impeccable wood finish to the aluminium rear plates with fish scale grill. The headband frame is a spring steel and the floating headband of soft protein leather is adjusted by means of continuous friction sliders. The ear pads are suede with a memory foam cushion and are a standard size and fitment so can be replaced easily with original or aftermarket pads.
Like the Sivga Robin, the Aiva goes beyond comfortable. The pads have just the right amount of cushioning to seat the ear cups on your ears without allowing the inner grille to make contact, while applying the least possible pressure on your head and conforming to the shape of your cheeks. I wouldn’t mind an extra few millimetres of depth in the pads but they’re comfortable as they are. I like that the headband sits close to the head when properly situated so the headphones don’t feel as bulky to wear as they look, and the friction slider adjustments don’t drift.
The headphones weigh 420 grams which is not inconsiderable but they’re not a strain to wear for long periods. The weight is only obvious when you immediately switch to a lighter pair of headphones. The openings are large enough for even my big ears to fit comfortably, and the pads do a good job of sealing around the ear to concentrate the sound from the driver towards the ear.
These are open-backed headphones so there is nothing to stop sound leaking from the enclosure. Using them on your commute or in a room with other people present won’t make you any friends. They also don’t block much external sound which is to be expected. One advantage of this is that the natural ambiance of your environment plays a roll in the stereo soundscape, much like it does with a pair of loudspeakers.
I tested the Aiva’s with a range of devices from the headphone output of my 16 inch MacBook Pro using the included adapter, to my Pro-Ject Head Box DS2B via a balanced connection. The Head Box is fully balanced from input to output and was used with both single-ended and balanced sources. I also tested the Aiva using the headphone output of my Cambridge 851E, which has a low output impedance and thus minimal impact on frequency response, and can drive heavy loads with ease though is unbalanced. All of the above drove the Aiva’s to high levels with ease, the Head Box naturally being the best choice and the 851E a close second.
Sonically I found the above graph a fair representation of the Aiva sound. The sound stage is large, expanding far beyond the cans themselves in width, depth and height. The stereo image remains cohesive and accurately portrayed with phasing issues in a mix easy to discern and positional information similarly obvious. Bass is even-handed – powerful when required, yet subtle without overshoot or blur. Mids are swept back, but to me this made the Aiva’s sound more like a pair of loudspeakers in the room than a typical pair of headphones. Some headphones can sound boxy and mid-heavy as the drivers are so close to the ear, and there’s no room ambiance to influence their frequency response. Not so the Aiva. The midband dip is noticeable but in a way that only enhances the performance. Vocals hang in the air and there’s a sparkle to the top end which brings out the shimmer in stringed instruments.
The top end packs a lot of detail. I’ve been privileged to hear some of the best equipment the industry has to offer – not necessary the most esoterically priced, but price doesn’t indicate performance in hi-fi. I have heard some of the best objective equipment out there, and experienced components that can reproduce levels of detail that I’d think impossible from any playback medium or recorded track. The Aiva’s are up there with the best in this regard. The amount of subtle detail they pull from a recording never fails to impress and delight in equal measure.
What I really took from my listening to the Aiva however was how easy they are to listen to, and how enjoyable they are. They might not be the most tonally accurate headphones on the market, but they’re not designed to be. If you want absolute accuracy, you can achieve that for significantly less money with something like the Beyerdynamic DT880.
The Aiva is intended for listening enjoyment above all else, and that is what they deliver in spades. I have many headphones to choose from here, but I’ve found myself returning to the Aiva time and time again as I’m always intrigued to see what little extra detail they can draw from a recording I thought I knew so well, and I find that regardless of what I play I am able to easily lose myself in the performance. These are traits of the finest loudspeakers and only the finest headphones.
To sum up, the Aiva’s are as much a visual showpiece as they are a sonic one. The choice of materials and quality of craftsmanship could command a hefty premium over what is a modest (in reference to their competition) $599 / £539 asking price. Sonically they are engaging, fun and emotive, with bags of detail and a pleasant sonic palette that is easy to listen to for hour upon hour. Highly recommended.
