LTA V1 v.1.0
The LTA V1 development is in the final stages, with the vast majority of design being finalized for the DIY kit versions, as well as the series production version of the headphone, both of which share component designs and only differ in manufacturing methods and materials used on some of the components. Manufacturing of the production version of the headphone is currently on hold due to the high cost of CNC machined components in low quantities, while the DIY versions can go into production immediately regardless of the choice of available materials and manufacturing methods. For that reason, following several iterations of each component, a version of the headphone based on close to final CAD designs has been manufactured and serves as a proof of concept. It's been post-processed and assembled into a unique unit that also represents one of many possible outcomes of the V1 DIY kit building process. Because of the way the headphone was designed, once the aluminium components are CNC machined, they will be perfectly compatible with plastic components as well. That means they can be easily replaced and the headphone can be upgraded at any point in the future.
This specific prototype has been fully built out of PA12 plastic, produced using Multi-Jet Fusion additive manufacturing technology. While this plastic is already superior to ABS which is usually used for headphone production due to lower costs, it represents the most affordable material option for this headphone. The V1 will be available in materials such as Carbon Fiber and Graphite reinforced polyamide, which can be up to 8 times more rigid and strong, but also quite a bit more expensive. Again, regardless of the material, all of the components are compatible and interchangeable, meaning that it's possible to start off by building an affordable headphone, and gradually upgrade it with superior parts.
The V1's baffle in standard form has been designed to accept drivers with a diameter of 46 mm, and can therefore accept a wide range of drivers available on the market designed specifically for this type of headphone. Furthermore, due to the fact that these components are produced using additive manufacturing technologies, the design of a baffle can be quickly and easily adapted to fit drivers of a smaller or a slightly larger diameter, if so requested in the future. In addition, adapters will be manufactured that will allow for smaller diameter drivers to fit into the standard baffle as well.
Out of the multiple drivers tested, I've chosen the excellent Elleven Acoustica P1 drivers to be in this proof of concept headphone, as they produce the best sound in this particular configuration, at least to my taste, and are objectively one of the best performing dynamic headphone drivers I've ever listened to, especially with instrumental and vocal music. That being said, there's a wide selection of compatible drivers available from multiple manufacturers, at multiple price points, and they can easily be replaced at any time, allowing for a lot of experimentation.
The headphone can be used with multiple types of ear pads as well, my favorite being the original Grado L-cushions for a focused, lively, extremely detailed and dynamic sound presentation. In combination with the P1 driver, the headphone has a very quick and tight low end, with wonderfully sweet and full mids, one the best I've ever heard from a dynamic headphone. Higher frequencies are slightly accentuated, although not to the extent typical for a headphone of this type. Instead, they provide a great sense of clarity in the sound, but without being overly aggressive. This aspect of the sound can be further fine tuned with the use of various acoustic foams and fabrics in front of the driver. One aspect of the sound that is particularly striking is the amount of detail effortlessly presented while listening to high quality recordings. Needless to say, as with all high quality headphones, a high quality source is a must in order to fully explore what the headphone is capable of. Poorly recorded music will have all its flaws exposed and amplified. The sound stage with L-cushions is medium in size, but offers good imaging and great separation. Using the P1 drivers in combination with the G-cushion ear pads results in a slightly higher level of comfort and a slightly more distant and laid back sound, with a bigger sound stage and a greater sense of openness in the sound. That being said, there are drivers on the market specifically designed for, and therefore better suited, for use with the bigger ear pads.
The ear cup shells and the headband pieces are the only components of this headphone designed to be post-processed by hand, unless they're the CNC machined versions, in which case they'll be brushed, chrome plated or anodized. Because of the way the ear cup shells were designed, they can be easily replaced, allowing for quick and easy headphone appearance changes in the future, especially if accompanied by matching headband pieces. The grill pieces were also designed with easy replacement in mind, and will be available in multiple custom designs and finishes.
In the case of this proof of concept prototype, the ear cup shells and headband pieces were finished in a metallic silver automotive coat, chosen because of the similarity to a CNC machined aluminium look intended for the production version of the headphone. Metallic silver base coat was covered with a high gloss clear coat, wet sanded and hand polished to a perfect mirror finish. You can find out more about the post-processing method here. MJF PA12 parts were dyed black and shot peened using nanospheres after production, which resulted in a finely textured, deep black appearance that contrasts the glossy silver components very nicely. Additionally, a very fine 316-grade Stainless Steel mesh was installed under the MJF PA12 grill, contrasting the matte black polyamide with an attractive metallic shine, while also matching the hand-polished Stainless Steel headband screws. The mesh is fine enough and has a large enough percentage of open area that it has no effect on the sound of the headphone, so it's not used for the purpose of sound tuning in this case. However, it is available in less transparent forms, in which case it can be used for sound tuning as well, as it's going to block the grill openings to a certain degree, depending on the particular mesh specification. Mesh is available in other materials as well, such as brass or copper, allowing for even more visual combinations.
Internally, the headphone sound can be further tuned by using driver spacers, which enable the owner to change the ear to driver distance with a range of 3 mm, which mainly impacts how pronounced the middle and upper middle frequencies are. On top of that, special acoustic mesh filters can be used in front of the driver, as well as on the grill behind the driver, for additional sound tuning options. Furthermore, the internal walls of the rear chamber can be lined with several types of materials and adapters in order to control the volume, shape and sound absorbing/reflecting properties of the cup, as well as to deal with standing waves. The default rear cylindrical chamber has been designed with a smooth surface in order to have some sort of an acoustically absorbing liner applied to it. This helps in dealing with the usual 2 kHz peaks typical for headphones of this type. Alternatively, the internal walls of the chamber can have complex 3D structures or textures designed onto them, and manufactured that way, making the walls uneven and offering an alternative acoustic treatment solution. The volume itself can also be filled with acoustic damping materials, for example the "angel hair" speaker cabinet filler material. In the case of the proof of concept build, the wall is lined with a 2 mm thick layer of EVA foam, which is good at absorbing mid to high frequencies, while the volume of the cup is left empty. This configuration leads to a certain sound character, but is in no way the only, or the ultimate solution. It all comes down to personal preference and the most important thing to remember is that all of the tuning options are reversible and virtually limitless.
This specific prototype has been fully built out of PA12 plastic, produced using Multi-Jet Fusion additive manufacturing technology. While this plastic is already superior to ABS which is usually used for headphone production due to lower costs, it represents the most affordable material option for this headphone. The V1 will be available in materials such as Carbon Fiber and Graphite reinforced polyamide, which can be up to 8 times more rigid and strong, but also quite a bit more expensive. Again, regardless of the material, all of the components are compatible and interchangeable, meaning that it's possible to start off by building an affordable headphone, and gradually upgrade it with superior parts.
The V1's baffle in standard form has been designed to accept drivers with a diameter of 46 mm, and can therefore accept a wide range of drivers available on the market designed specifically for this type of headphone. Furthermore, due to the fact that these components are produced using additive manufacturing technologies, the design of a baffle can be quickly and easily adapted to fit drivers of a smaller or a slightly larger diameter, if so requested in the future. In addition, adapters will be manufactured that will allow for smaller diameter drivers to fit into the standard baffle as well.
Out of the multiple drivers tested, I've chosen the excellent Elleven Acoustica P1 drivers to be in this proof of concept headphone, as they produce the best sound in this particular configuration, at least to my taste, and are objectively one of the best performing dynamic headphone drivers I've ever listened to, especially with instrumental and vocal music. That being said, there's a wide selection of compatible drivers available from multiple manufacturers, at multiple price points, and they can easily be replaced at any time, allowing for a lot of experimentation.
The headphone can be used with multiple types of ear pads as well, my favorite being the original Grado L-cushions for a focused, lively, extremely detailed and dynamic sound presentation. In combination with the P1 driver, the headphone has a very quick and tight low end, with wonderfully sweet and full mids, one the best I've ever heard from a dynamic headphone. Higher frequencies are slightly accentuated, although not to the extent typical for a headphone of this type. Instead, they provide a great sense of clarity in the sound, but without being overly aggressive. This aspect of the sound can be further fine tuned with the use of various acoustic foams and fabrics in front of the driver. One aspect of the sound that is particularly striking is the amount of detail effortlessly presented while listening to high quality recordings. Needless to say, as with all high quality headphones, a high quality source is a must in order to fully explore what the headphone is capable of. Poorly recorded music will have all its flaws exposed and amplified. The sound stage with L-cushions is medium in size, but offers good imaging and great separation. Using the P1 drivers in combination with the G-cushion ear pads results in a slightly higher level of comfort and a slightly more distant and laid back sound, with a bigger sound stage and a greater sense of openness in the sound. That being said, there are drivers on the market specifically designed for, and therefore better suited, for use with the bigger ear pads.
The ear cup shells and the headband pieces are the only components of this headphone designed to be post-processed by hand, unless they're the CNC machined versions, in which case they'll be brushed, chrome plated or anodized. Because of the way the ear cup shells were designed, they can be easily replaced, allowing for quick and easy headphone appearance changes in the future, especially if accompanied by matching headband pieces. The grill pieces were also designed with easy replacement in mind, and will be available in multiple custom designs and finishes.
In the case of this proof of concept prototype, the ear cup shells and headband pieces were finished in a metallic silver automotive coat, chosen because of the similarity to a CNC machined aluminium look intended for the production version of the headphone. Metallic silver base coat was covered with a high gloss clear coat, wet sanded and hand polished to a perfect mirror finish. You can find out more about the post-processing method here. MJF PA12 parts were dyed black and shot peened using nanospheres after production, which resulted in a finely textured, deep black appearance that contrasts the glossy silver components very nicely. Additionally, a very fine 316-grade Stainless Steel mesh was installed under the MJF PA12 grill, contrasting the matte black polyamide with an attractive metallic shine, while also matching the hand-polished Stainless Steel headband screws. The mesh is fine enough and has a large enough percentage of open area that it has no effect on the sound of the headphone, so it's not used for the purpose of sound tuning in this case. However, it is available in less transparent forms, in which case it can be used for sound tuning as well, as it's going to block the grill openings to a certain degree, depending on the particular mesh specification. Mesh is available in other materials as well, such as brass or copper, allowing for even more visual combinations.
Internally, the headphone sound can be further tuned by using driver spacers, which enable the owner to change the ear to driver distance with a range of 3 mm, which mainly impacts how pronounced the middle and upper middle frequencies are. On top of that, special acoustic mesh filters can be used in front of the driver, as well as on the grill behind the driver, for additional sound tuning options. Furthermore, the internal walls of the rear chamber can be lined with several types of materials and adapters in order to control the volume, shape and sound absorbing/reflecting properties of the cup, as well as to deal with standing waves. The default rear cylindrical chamber has been designed with a smooth surface in order to have some sort of an acoustically absorbing liner applied to it. This helps in dealing with the usual 2 kHz peaks typical for headphones of this type. Alternatively, the internal walls of the chamber can have complex 3D structures or textures designed onto them, and manufactured that way, making the walls uneven and offering an alternative acoustic treatment solution. The volume itself can also be filled with acoustic damping materials, for example the "angel hair" speaker cabinet filler material. In the case of the proof of concept build, the wall is lined with a 2 mm thick layer of EVA foam, which is good at absorbing mid to high frequencies, while the volume of the cup is left empty. This configuration leads to a certain sound character, but is in no way the only, or the ultimate solution. It all comes down to personal preference and the most important thing to remember is that all of the tuning options are reversible and virtually limitless.
PERFORMANCE
In order to evaluate the performance of various prototype headphones, I've built a measurement rig using solid wood and a high quality measurement microphone capsule. It's a simple measurement rig, with a microphone mounted flush to one of the two parallel flat wooden panels. The panels of the measurement rig are spaced apart exactly to the width of my head, in order to simulate realistic headband clamping force. The rig itself is extremely rigid and acoustically inert, with the panels glued and screwed together, additionally covered with bitumen vibration dampening sheets. The raw frequency response of the microphone capsule used is perfectly flat from 50 to 16000 Hz, with a gentle roll-off on either end of the spectrum, so it covers the audible range well enough. However, installed in the measurement rig, it tends to amplify high frequencies ever so slightly, so the frequency response graphs aren't entirely reliable above around 5 kHz, as the range above it tends to be a couple of dB higher in SPL than what I hear when listening to the headphones.
Note that the measurements I'm doing are not absolute, they're relative. Their purpose is not to show an absolutely accurate frequency response at the ear drum, but instead to show the effects of various changes done to the headphones throughout the sound tuning process, as well as to detect and eliminate unwanted peaks, dips or other sound issues. The final tuning is always done by listening to the headphones.
I'm using a Beyerdynamic DT770Pro 250 frequency response graph as a tool for comparison. You can see that while the frequency response of the DT770 is not identical to those recorded on professional dummy heads, it still clearly resembles them and all of the typical features of this headphone's FR are well represented. Both headphones were measured using ARTA software on the same rig, with the same exact setup, with both headphones volume matched at about 95 dB @ 1000 Hz. The graphs are results of raw Log-frequency sweeps without any correction curves applied.
Note that the measurements I'm doing are not absolute, they're relative. Their purpose is not to show an absolutely accurate frequency response at the ear drum, but instead to show the effects of various changes done to the headphones throughout the sound tuning process, as well as to detect and eliminate unwanted peaks, dips or other sound issues. The final tuning is always done by listening to the headphones.
I'm using a Beyerdynamic DT770Pro 250 frequency response graph as a tool for comparison. You can see that while the frequency response of the DT770 is not identical to those recorded on professional dummy heads, it still clearly resembles them and all of the typical features of this headphone's FR are well represented. Both headphones were measured using ARTA software on the same rig, with the same exact setup, with both headphones volume matched at about 95 dB @ 1000 Hz. The graphs are results of raw Log-frequency sweeps without any correction curves applied.
As can be seen, the LTA V1 prototype has a very smooth frequency response without major peaks or dips, going through frequency sweeps while listening to them confirms that. The area from 50 to 1500 Hz is particularly flat, explaining the extremely accurate vocal and instrument reproduction, as well as the incredibly tight, punchy and clean low end, something that this headphone excels at. The high frequencies above 5 kHz of both headphones are slightly more rolled-off in reality than what my measurements show.
Note that I'm not using the DT770 as a benchmark, and that the performance difference between the two headphones is not fully illustrated by these graphs, as it goes beyond the frequency response alone. The difference in sound resolution, dynamics, transparency, clarity, level of detail, speed and just the overall sense of quality of reproduction is massive in V1's favor, as it should be, considering the V1's drivers alone cost almost twice as much as the DT770's.
The sound of the LTA V1 is also, for the lack of a better term, very musical. It makes music involving and fun to listen to in a way that few headphones I've ever heard managed to, and it's all thanks to that sweet mid-range and a very quick and well controlled sound. This might actually be the most impressive thing about it, because usually headphones with this level of detail, clarity and speed tend to be overly analytical and cold, but the V1 manages to avoid that very successfully. From personal experience, speaking subjectively, I would put the V1 at the level of the Beyerdynamic T1 (possibly my favorite dynamic headphone ever) in virtually every aspect of sound performance other than the size of the soundstage and the bass extension below 50 Hz, and even above the T1 in terms of mids, and how they reproduce vocal and instrumental music. The fact that it can be built for approximately 2/3 of the cost makes it even more impressive. Keep in mind that this is still a prototype, without the use of more expensive reinforced polyamides and CNC machined aluminium in it's production. Both of those materials are going to drastically increase the overall rigidity of the ear cup assemblies, resulting in an even better sound.
Note that I'm not using the DT770 as a benchmark, and that the performance difference between the two headphones is not fully illustrated by these graphs, as it goes beyond the frequency response alone. The difference in sound resolution, dynamics, transparency, clarity, level of detail, speed and just the overall sense of quality of reproduction is massive in V1's favor, as it should be, considering the V1's drivers alone cost almost twice as much as the DT770's.
The sound of the LTA V1 is also, for the lack of a better term, very musical. It makes music involving and fun to listen to in a way that few headphones I've ever heard managed to, and it's all thanks to that sweet mid-range and a very quick and well controlled sound. This might actually be the most impressive thing about it, because usually headphones with this level of detail, clarity and speed tend to be overly analytical and cold, but the V1 manages to avoid that very successfully. From personal experience, speaking subjectively, I would put the V1 at the level of the Beyerdynamic T1 (possibly my favorite dynamic headphone ever) in virtually every aspect of sound performance other than the size of the soundstage and the bass extension below 50 Hz, and even above the T1 in terms of mids, and how they reproduce vocal and instrumental music. The fact that it can be built for approximately 2/3 of the cost makes it even more impressive. Keep in mind that this is still a prototype, without the use of more expensive reinforced polyamides and CNC machined aluminium in it's production. Both of those materials are going to drastically increase the overall rigidity of the ear cup assemblies, resulting in an even better sound.
UPDATE
An update to the performance status of the V1 Prototype. I've build another prototype with slightly updated parts, with very minor design changes, just an added second grill on the rear opening of the ear cup that helps keep the filters or metal mesh sandwiched in place under the main, outer grill. It adds nothing to the transparency of the overall opening, as it's perfectly aligned with the outer grill. In addition, singe the entire driver baffle is produced out of MJF PA12 material, the outer decorative baffle ring that is otherwise glued to the baffle, has been printed together with the driver baffle, giving the component some additional rigidity. The cups also feature a black metallic high-gloss finish, the same kind that can be seen in the post-processing guide.
More importantly, this configuration features more advanced acoustic treatment than the previously shown one. The internal walls of the rear cup chamber are lined with a layer of Dynamat, and then a layer of 3 mm thick acoustic felt on top of it. This makes the cup more inert, and reduces the reflections off of the internal walls. In addition to that, the parts feature something I've been experimenting with for a while, and that is using liquid glass, or a special type of epoxy resin, to fill in the cutouts in the components. The reason for doing this is the fact that this resin, once cured, is extremely rigid and inert, far more than any plastic material I could use to make the components out of, while being only slightly heavier than plastic at the same time. This means that printing components with cutouts, and then filling them in with epoxy resin, leads to more rigid and inert components than they would have been if they were to be printed without cutouts to begin with. The amount of resin used leads to different effects, so in a way, this method can be used to control the resonant properties of plastic parts. The improvements in rigidity will be even more noticeable when the raw components themselves get produced out of superior materials such as the Carbon Fiber reinforced Polyamide, and will be on this level of performance even without filling them with epoxy resin. Another change compared to the previously shown configuration is the mesh used under the grill, which is not a stainless steel mesh, but a polyester acoustic filter, slightly more transparent than the stainless steel mesh.
More importantly, this configuration features more advanced acoustic treatment than the previously shown one. The internal walls of the rear cup chamber are lined with a layer of Dynamat, and then a layer of 3 mm thick acoustic felt on top of it. This makes the cup more inert, and reduces the reflections off of the internal walls. In addition to that, the parts feature something I've been experimenting with for a while, and that is using liquid glass, or a special type of epoxy resin, to fill in the cutouts in the components. The reason for doing this is the fact that this resin, once cured, is extremely rigid and inert, far more than any plastic material I could use to make the components out of, while being only slightly heavier than plastic at the same time. This means that printing components with cutouts, and then filling them in with epoxy resin, leads to more rigid and inert components than they would have been if they were to be printed without cutouts to begin with. The amount of resin used leads to different effects, so in a way, this method can be used to control the resonant properties of plastic parts. The improvements in rigidity will be even more noticeable when the raw components themselves get produced out of superior materials such as the Carbon Fiber reinforced Polyamide, and will be on this level of performance even without filling them with epoxy resin. Another change compared to the previously shown configuration is the mesh used under the grill, which is not a stainless steel mesh, but a polyester acoustic filter, slightly more transparent than the stainless steel mesh.
In terms of performance, this configuration is a noticeable improvement over the previous one subjectively speaking, not by a large margin, as it's mostly an identical headphone, with the same Elleven Acoustica P1 drivers and Grado L-cushion ear pads, but still an improvement. The acoustic treatment of the rear chamber has led to a slightly more even frequency response, with a 2 kHz peak slightly reduced, and an overall smoother sound, particularly in the high frequencies. On the other hand, the additional rigidity and mass of the components due to the epoxy resin filling has led to a tighter, quicker and punchier bass response.
Below, the frequency response can be seen in a direct comparison to the DT770, without any smoothing applied, 1/24 oct setting in ARTA, giving the most detailed graphs possible. As can be seen, the curve is smoother and more even than previously, with slightly increased SPL in the low end, and flatter upper mid range.
Below, the frequency response can be seen in a direct comparison to the DT770, without any smoothing applied, 1/24 oct setting in ARTA, giving the most detailed graphs possible. As can be seen, the curve is smoother and more even than previously, with slightly increased SPL in the low end, and flatter upper mid range.
CSD Waterfall plot can be seen below, although the validity of this measurement is questionable when done on a primitive measurement rig such as mine.
Below, I've added a collection of three measurements with an identical headphone, without being removed from the measurement rig. The only difference is the adjustment of the headband size, leading to slightly tighter and stronger clamping force with each reduction in size. Green line is the lightest clamping force, red the strongest. This is to show how the clamping force of the headband affects the sound of a headphone, and how important it is to adjust the size of the headband when wearing a headphone, enabling an optimal seal between the ear pad and the ear. This is also obviously an important factor when attempting to couple an ear pad with a flat piece of wood in order to achieve a proper measurement. In addition, the headband spring I'm using currently is already 3 years old, and has been stretched out significantly, meaning that a brand new spring would lead to an even higher clamping force, and an even better seal, which is crucial with these headphones.
In any case, the measurements shown here are the worst-case-scenario ones, using the most affordable materials to produce the headphone parts, not utilizing all possible acoustic treatment options, with already slightly worn-out ear pads and an old headband spring. Despite that, the headphones perform extremely well.
In any case, the measurements shown here are the worst-case-scenario ones, using the most affordable materials to produce the headphone parts, not utilizing all possible acoustic treatment options, with already slightly worn-out ear pads and an old headband spring. Despite that, the headphones perform extremely well.
4K RESOLUTION RENDERS
RAW PARTS
Photographs and videos of 3D printed V1 prototype parts before and during post-processing. Note that some of the materials used during prototyping will be replaced by even better and more expensive materials in some of the production versions of the headphone for even greater acoustic performance, as well as improved mechanical properties. More affordable materials were chosen for prototyping in order to reduce R&D costs.
FINISHED PARTS AND FULL ASSEMBLY
Fully finished and post-processed prototype parts, done by hand following the procedures described in the post-processing guide. A fully assembled headphone can be seen featuring the excellent Elleven Acoustica P1 drivers and two types of original Grado ear pads, in a combination of matte black MJF PA12 plastic and a high gloss metallic silver paint job. Please note that the prototype parts have been stress tested, abused, slightly modified, disassembled and assembled dozens of times, etc. Therefore, a certain level of wear and certain imperfections can be seen on them that won't be found on the final production versions of the headphone. Also, certain components have been manufactured out of different materials than intended for final production versions of the headphone, in order to reduce R&D costs. These components are identical to final ones in terms of appearance and dimensions, but posses inferior mechanical characteristics and aren't as durable. The final versions of the headphone will feature reinforced polyamides in the construction, as well as CNC machined metal components, redesigned and much more substantial hinges, additional fasteners securing the drivers in place, etc. For more information about the plans regarding the production versions of the V1 headphone, visit the V1 page.