A typical merger-and-acquisition process is time-consuming and expensive, even for the largest, well-staffed private equity firms. In addition to spending countless hours meeting with senior executives of potential targets and modeling financial outcomes, these groups spend millions of dollars on external advisers: accountants, lawyers, and management consultants.

Since expenses for external advisers are not reimbursed if a deal falls through, PE firms wait until they are certain of their interest before engaging costly specialists such as consultants from McKinsey, BCG, or Bain to perform extensive commercial research on the market and the target company.

DiligenceSquared, a startup that was part of YC’s Fall 2025 cohort, says that with the help of AI, it can provide top-tier consultancy-quality commercial research at a fraction of the traditional cost.

The startup’s co-founders, Frederik Hansen and Søren Biltoft, possess deep expertise in private equity due diligence. Hansen was formerly a principal at Blackstone, where he commissioned these reports for multiple billion-dollar buyouts. Meanwhile, Biltoft spent seven years in BCG’s private equity practice leading these types of diligence efforts.  

Since launching in October, Hansen’s and Biltoft’s industry experience has helped DiligenceSquared complete multiple projects for several of the world’s largest PE firms and mid-market funds, Hansen tells TechCrunch.

That early traction convinced Damir Becirovic, a former Index Ventures partner, to lead DiligenceSquared’s $5 million seed round out of his new VC firm, Relentless.

Instead of relying on expensive management consultants, the startup uses AI voice agents to conduct interviews with customers of the companies the PE firms are considering buying.

DiligenceSquared is applying the same AI-interview model seen in consumer research startups like Keplar, Outset, and Listen Labs, which in January raised $69 million at a $500 million valuation. But Hansen and Biltoft argue that their due-diligence process and final outputs are fundamentally different from the consumer research produced by these startups.

PE firms can pay $500,000 to $1 million for McKinsey, Bain, or BCG to interview dozens of corporate customers, including C-suite executives, and produce 200-page reports synthesizing those insights with proprietary market data, Hansen said. To ensure the quality of the analysis, DiligenceSquared involves senior human consultants who verify the accuracy and commercial insights of the final output.

Since AI is doing a lot of the groundwork, the startup claims it can provide the analysis for just $50,000.

“We are taking these great insights that were previously reserved for the very big decisions, and now we make them more accessible,” Hansen said. Because of the lower price point, PE firms are now far more willing to engage DiligenceSquared earlier in the process, well before they have high conviction in a deal.

DiligenceSquared isn’t the only company trying to disrupt the diligence market. Its main competitor, Bridgetown Research, raised a $19 million Series A co-led by Accel and Lightspeed in February 2026.

In addition to Hansen and Biltoft, DiligenceSquared was co-founded by Harshil Rastogi, a former Google engineer.

If you’re driving in an F1 race and hitting speeds of 220 mph (354 kph), you really don’t want parts of the car falling off as you hurtle along, or, more importantly, to suffer nerve damage because of a problem with your vehicle.

But that’s exactly what’s happening with Aston Martin’s car, leaving drivers Fernando Alonso and Lance Stroll unlikely to finish the first race of the new F1 season in Australia on Sunday.

In testing, the car, powered by a Honda engine, has been vibrating so badly that parts of it have been dropping off, with the vibrations reaching the drivers, too.

The issue surfaced as teams adapt to new engine rules designed to boost efficiency and sustainability in a change that forced widespread redesigns in recent months.

While Honda supplies the power units that may be contributing to the vibration problem, Aston Martin’s chassis design and setup affect how the vibrations reach the drivers, making it a problem rooted in both engine performance and car design.

Engineers have been working to reduce the vibrations, but it seems unlikely that Alonso and Stroll will be able to complete Sunday’s race.

“That vibration into the chassis is causing a few reliability problems,” Aston Martin team principal Adrian Newey said in comments to the media on Thursday, adding that the problem includes “mirrors falling off, tail lights falling off.”

Newey said “the much more significant problem is that the vibration is transmitted ultimately into the driver’s fingers. So Fernando [Alonso] is of the feeling that he can’t do more than 25 laps consecutively before he will risk permanent nerve damage to his hands. Lance [Stroll] is of the opinion that he can’t do more than 15 laps before that threshold.”

Commenting on the unusual situation on Thursday, Alonso said, “For us it’s just vibrating everything. But it’s not only for us, I think the car is shrugging a little bit. The vibrations coming from the engine are hurting a little bit the components in the car and the drivers; we feel them, we feel our body with this frequency of the vibrations that you feel after 20 or 25 minutes, a little bit numb.”

It’s certainly a bizarre turn of events. While there have been instances in the past of F1 drivers riding in an uncomfortable condition, this appears to be the first time that a team is facing cutting a race short due to health risks from vibrations.

Grado Labs is expanding its Signature Series with the new Signature S550, a $995 USD open-back headphone that stays true to the company’s Brooklyn built design philosophy while introducing a slightly more relaxed sonic balance. As the fourth model in the growing Signature Line, the S550 carries forward the same core Grado principles: low mass dynamic drivers, careful material selection, and tuning that prioritizes speed, transient snap, and unfiltered detail.

The difference this time comes down to voicing. Where some Grado models lean forward and urgent, the Signature S550 is tuned, according to Grado Labs, to ease back just enough to introduce added warmth and a smoother top end while preserving the brand’s trademark punch, speed, and immediacy. Having already been impressed by the precision, control, and refinement of the Signature S950, the S550 appears positioned as a slightly more relaxed and accessible take on that formula at $995 USD, aimed at delivering long term listenability without abandoning the core Grado energy.

We plan to find out whether those design claims hold up when we audition it at CanJam NYC 2026 this weekend.

S2 Dynamic Driver Optimized for All Wood Open-back Design

At the heart of the Signature S550 is Grado’s 50mm S2 dynamic driver, tuned specifically to work in concert with its all wood open-back enclosure. Rather than introduce an entirely new driver platform, Grado Labs focused on refining the relationship between the existing S2 driver and the acoustic behavior of the wooden housing. The goal, according to Grado, is a presentation that leans warmer and more forgiving while preserving speed, detail, and spatial openness.

We have not yet heard the S550, so those claims remain just that for now. What made the Signature S950 so impressive in our evaluation was its stronger and more controlled bass response, with tighter impact, improved resolution, and a noticeably faster character than many earlier Grado models. The top end was also significantly smoother, maintaining the brand’s signature energy without tipping into the brightness that has been a common criticism over the years. Comfort was improved as well, making longer sessions far easier.

Brazilian Walnut Housing Shaped for Stability and Tonal Balance

The Signature S550 uses housings crafted entirely from Brazilian Walnut, continuing Grado Labs’s long standing commitment to wood as a functional acoustic material rather than a cosmetic flourish. Each housing is individually formed, with natural variations in grain pattern ensuring that no two pairs are identical.

Walnut is selected for its density, internal damping properties, and structural stability. According to Grado, those characteristics help support a fuller and more balanced tonal presentation while maintaining consistent acoustic behavior over time. The rigidity of the wood also plays a role in controlling resonance within the open-back design. Grado further notes that the material is sourced with attention to sustainable practices, supporting long term availability while respecting the environments where it is harvested.

Detachable Cable System Brings Long Overdue Flexibility

The Signature S550 ships with Grado’s Silver detachable cable, designed to be lighter, softer, and more flexible than the company’s legacy fixed leads. Each earcup is terminated with a 4 pin balanced mini XLR connection, allowing users to swap cables depending on source gear or listening preference. The included cable terminates in a 3.5mm mini plug and includes a 6.3mm adapter for broad compatibility with portable players, desktop DAC amps, and traditional headphone outputs.

This marks a significant shift for Grado Labs. For decades, Grado stuck with permanently attached cables that sounded fine but had a habit of snagging on chair arms, desk corners, and just about everything else. The newer Signature Series models, including the HP100 SE, were the first to embrace detachable cabling, reflecting how much the broader headphone market has evolved.

The rise of the Head-Fi era pushed brands like Sennheiser, Audeze, Meze Audio, Dan Clark Audio, and HiFiMAN toward user replaceable cables years ago. Beyond simple convenience, detachable systems allow listeners to tailor length, termination, and in some cases subtle system synergy with different amplifiers and sources. The key is flexibility and practicality, not chasing exaggerated cable myths or paying absurd prices for incremental changes.

Comfort, Fit, and Personalization with the Signature Headband System

The Signature S550 ships with Grado’s new B cushions and remains compatible with the brand’s full range of ear pads, allowing listeners to tailor both comfort and sonic balance to personal preference. Pad selection has always played a meaningful role in Grado designs, influencing soundstage width, bass presence, and perceived treble energy. In addition to the B cushions, the S550 supports Grado’s S, F, L, and G ear cushions, each offering distinct variations in spatial presentation, comfort, and low frequency impact.

Like all models in the Signature Line, the S550 uses the updated Signature headband assembly from Grado Labs. A flexible metal support is integrated within the leather headband, enabling gentle adjustment for a more personalized fit over time. The S550 adopts the narrower leather strap seen on the S750 and incorporates engraved metal gimbals, stainless steel height rods, reinforced junction blocks, and controlled housing rotation for improved durability and long term stability.

We are hopeful the S550 carries forward the improved padding introduced with the Signature S950 and HP100 SE, both of which represented a noticeable step forward in comfort compared to earlier generations. If that refinement continues here, extended listening sessions should be far less of a negotiation.

Technical Specifications & Amplification Considerations

The Signature S550 is an open air dynamic headphone built around a 50mm driver and rated at 38 ohms nominal impedance. Grado specifies frequency response from 6 Hz to 44 kHz, total harmonic distortion below 0.2% at 100dB, and sensitivity of 112dB @ 1/mW. Driver matching is rated to an extremely tight 0.005dB, reflecting careful channel consistency. The headphone weighs 335 grams without the cable, keeping it relatively manageable for extended listening sessions given its full size open-back construction.

With a 38 ohm load and high sensitivity, the S550 is not especially difficult to drive and should pair comfortably with quality portable players, desktop DAC amps, and even stronger integrated amplifier headphone stages. That said, like most resolving open-back designs, it is likely to benefit from a clean, stable source with adequate current delivery, where improved control and dynamic headroom can translate into tighter bass response and greater overall refinement.

The Bottom Line

The Signature S550 reflects a measured evolution from Grado Labs. Rather than introduce a radically new platform, Grado has refined its existing 50mm S2 dynamic driver, paired it with a Brazilian Walnut open-back housing, added detachable cables, and continued with the upgraded Signature headband system. The stated goal is straightforward: retain the speed, immediacy, and dynamic punch associated with the brand while shifting the tonal balance toward greater warmth and smoother treble for longer listening comfort.

At $995 USD, the S550 enters a competitive segment that includes strong offerings from beyerdynamic, Meze Audio, Sennheiser, Audeze, and Audio-Technica. Many of those brands emphasize planar magnetic designs or studio reference neutrality. The S550 appears aimed at listeners who prefer dynamic driver energy and open back spaciousness, but who want a more relaxed overall presentation than some earlier Grado models delivered.

If the tuning achieves what Grado describes, the S550 could serve both long time fans seeking refinement and newcomers curious about the brand’s sound without the sharper edge that once defined it. We will know more once we spend time with it.

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In the 1970s, the USSR had an undersea cable connecting a major naval base at Petropavlovsk to the Pacific Fleet headquarters at Vladivostok. The cable traversed the Sea of Okhotsk, which, at the time, the USSR claimed. It was off limits to foreign vessels, heavily patrolled, and laced with detection devices. How much more secure could it be? Against the US Navy, apparently not very secure at all. For about a decade starting in 1972, the Navy delivered tapes of all the traffic on the cable to the NSA.

Top Secret

You need a few things to make this a success. First, you need a stealthy submarine. The Navy had the USS Halibut, which has a strange history. You also need some sort of undetectable listening device that can operate on the ocean floor. You also need a crew that is sworn to secrecy.

That last part was hard to manage. It takes a lot of people to mount a secret operation to the other side of the globe, so they came up with a cover story: officially, the Halibut was in Okhotsk to recover parts of a Soviet weapon for analysis. Only a few people knew the real mission. The whole operation was known as Operation Ivy Bells.

The Halibut

The Halibut is possibly the strangest submarine ever. It started life destined to be a diesel sub. However, before it launched in 1959, it had been converted to nuclear power. In fact, the sub was the first designed to launch guided missiles and was the first sub to successfully launch a guided missile, although it had to surface to launch.

Oddly enough, the sub carried nuclear cruise missiles and its specific target, should the world go to a nuclear war, was the Soviet naval base at Petropavolvsk.

By 1965, the sub had been replaced for missile duty by newer submarines. It was tapped to be converted for “special operations.” Under the guise of being a deep-sea recovery vehicle, the Halibut received skids to settle on the seabed, side thrusters, specialized anchors, and a host of electronic equipment, including “the Fish” a 12-foot-long array of cameras, sonar, and strobe lights weighing nearly two tons. The “rescue vehicle” on its stern didn’t actually detach. It was a compartment for deploying saturation divers.

An early mission was Operation Sand Dollar. Halibut found the wreck of the Soviet K-129, which the US would go on to recover in another top secret mission, looking for secrets and Soviet technology.

When it came time to deploy the listening device on an underwater cable, Halibut was perfect. It could park a safe distance away, deploy saturation divers, and recover them. If you want to see more about the Halibut, check out the [Defence Central] video below.

The Listening Device

This wasn’t a hidden microphone in a briefcase. It was a 20-foot, six-ton pressure vessel parked on the ocean floor. Details are murky, but there was another part, probably smaller, that clamped around the cable. Working inductively, it didn’t pierce the cable for fear the Soviets would notice that. In addition, if they raised the cable for maintenance, the device was made to break away and sink to the bottom.

Needless to say, tapping a cable on the ocean floor isn’t easy. First, they had to locate the cable. Luckily, there were signs at either end telling fishing vessels to avoid the area. That helped, but they still had to search for the 5-inch wide cables. They found them at least 400 feet below the surface, some 120 miles offshore.

Saturation diving was a relatively new idea at the time, and the Navy’s SeaLab experiments had given them several years of experience with the technology. While commercial saturation dives started in 1965, it was still exotic technology in 1971. The first mission simply recorded a bit of data on the submarine and returned it. Once it was proven, the sub returned with the giant tap device and installed it.

It took four divers to position the big tap. Even then, you couldn’t just leave it there. The device used tapes and required service once a month. So Halibut or another sub had to visit each month to swap tapes out. We couldn’t find out what the power source for the bug was, so they probably had to change the batteries, too.

The Soviets didn’t consider the cable to be at risk for eavesdropping, so much of the traffic on the cable was in the clear. It was a gold mine of intelligence information, and many credit the information gained as crucial to closing the SALT II treaty talks.

Secondary Mission

Most of the crews participating in Operation Ivy Bells didn’t have clearance to know what was going on. Instead, they thought they were on a different secret mission to retrieve debris from Soviet anti-ship missiles.

To keep the story believable, the crew actually did recover a large number of parts from the subject Soviet missiles. Turns out, analysis of the debris did reveal some useful information, so two spy missions for the price of one.

Presumably, the assumption would be that if the Soviets heard a sub was scavenging missile parts, it might qualify as a secret, but it would hardly be a surprise. They couldn’t have imagined the real purpose of the submarine.

Future Taps

Later undersea taps were created that used radioisotope batteries and could store a year’s data between visits that tapped other Soviet phone lines. Submarines Parche, Richard B. Russel, and Seawolf saw duty with some of these other taps as well as taking over for Halibut when it retired four years after the start of Operation Ivy Bells.

The original Okhotsk tap would have operated for many more years if it were not for [Ronald Pelton]. A former NSA employee, he found himself bankrupt over $65,000 of debt. In 1980, he showed up at the Soviet embassy in Washington and offered to sell what he knew.

He knew a number of things, including what was going on with Operation Ivy Bells. That data netted him $5,000 and, overall, he got about $35,000 or so. Oh, he also got life in prison when, in 1985, a Soviet defector revealed he had been the initial contact for [Pelton].

The Soviets didn’t immediately act on [Pelton’s] intel, but by 1981, the Americans knew something was up. A small fleet of ships was parked right over the device. The USS Parche was sent to retrieve it, but they couldn’t find it. Today, it (or, perhaps, a replica) is in the Great Patriotic War Museum in Moscow.

A surprising amount of the Cold War was waged under the sea. Not to mention in the air.

Curious about split keyboards, but overwhelmed by the myriad options for every little thing? You should start with [thehaikuza]’s excellent Beginner’s Guide to Split Keyboards.

Your education begins with the why, so you can skip that if you must, but the visuals are a nice refresher on that front.

He then gets into the types of keyboards — you got your standard row-staggered rectangles that we all grew up on, column-staggered, and straight-up ortholinear, which no longer enjoy the popularity they once did.

At this point, the guide becomes a bit of a Choose Your Own Adventure story. If you want a split but don’t want to learn to change much if at all about your typing style, keep reading, because there are definitely options.

But if you’re ready to commit to typing correctly for the sake of ergonomics, you can skip the Alice and other baby ergo choices and get your membership to the light side. First are features — you must decide what you need to get various jobs done. Then you learn a bit about key map customization, including using a non-QWERTY layout. Finally, there’s the question of buying versus DIYing. All the choices are yours, so go for it!

Via reddit

Is That a Bat In Your Pocket?

Need something ultra-portable for those impromptu sessions at the coffee shop (when you can actually find a table)? You can’t get much smaller than the 28-key Koumori by [fata1err0r81], which means “bat” in Japanese. Here’s the repo.

This unibody beauty runs on an RP2040 Zero using QMK firmware. That 40 mm Cirque track pad has a glass overlay, which is a really nice touch. It’s actually a screen protector for a smart watch, and the purple bit is some craft vinyl cut to size.

Protecting that glass overlay is a case with a handle and a magnetic lid. Both the PCB and the case were designed in Ergogen, which as you know, I really like to see people using.

As you might have guessed, those are Kailh V1 choc switches with matching key caps. If you want a bat for your pocket, the build guide is simple, and there aren’t even any microscopic parts involved.

The Centerfold: [arax20]’s Been Workin’ On the Railroader

Okay, before you do anything, go check out the image gallery to see this baby glowing and being worn like a katana or something. Yeah.

So [arax20] built this as a gift for an ex. She likes the ergonomics of splits, but didn’t want cables between the halves and feels the space between is otherwise wasted. Really? There’s so much you can put there, from cats to mice to coffee mugs.

Do you rock a sweet set of peripherals on a screamin’ desk pad? Send me a picture along with your handle and all the gory details, and you could be featured here!

Historical Clackers: the Mysterious Rico

Frustratingly little is known about the Rico, a 1932 index machine out of Nuremburg, Germany. But the Antikey Chop has over a dozen books on typewriters, and only two have any mention of the Rico: Adler’s Antique Typewriters, From Creed to QWERTY, and Dingwerth’s Kleines Lexikon Historischer Schreibmaschinen.

Adler calls it a “pleasant toy typewriter with indicator selecting letters from a rectangular index”, saying nothing more descriptive. Dingwerth’s volume both dates the Rico and lists the maker as Richard Koch & Co. of Nuremburg.

The Rico was ambitiously declared the No. A1 model, though there is no evidence of any other model in existence. It was made mostly of stamped tin, though the type element was made of brass. The type element looked like a tube cut in half lengthwise, and worked in a similar fashion to the Chicago typewriter with its type sleeve.

There are some interesting things about the Rico nonetheless. The platen could not accommodate paper wider than 4″, for one thing. There is also no inking system to speak of. Weirder still, this oversight isn’t mentioned in the original instructions. Most people just taped a couple inches of typewriter ribbon between the element and the platen and called it good .

To use the thing, you would move the center lever to the character you wanted. The lever has a pin in the bottom, and each character has a dimple in it for the pin to sit. The lever on the left side was used to pivot the carriage toward the type element in order to print. In total, the Rico typed 74 characters plus Space.

Finally, Someone’s Made a Braille Keyboard, and It’s Inexpensive

Once upon a time, New Jersey high schooler Umang Sharma saw an ad for a Braille keyboard. The price? A cool seven grand. For a keyboard. No problem, he thought. I can build my own.

The astute among you will notice that there’s a Logitech keyboard in the picture, with what look like key cap hats. That is exactly what’s happening here. Sharma starts with a standard keyboard base, one that is usually either donated or was previously discarded.

He then focuses on the most important accessibility layer, which is tactile Braille key caps that are both readable and durable. In 2022, Sharma launched the non-profit Jdable to bring affordable, accessible design to people with disabilities.

He designed the key caps himself, and uses a combination of 3D printing and other materials to create them in bulk. They’re printed using a combination of PETG for toughness, TPU for grippiness, and resin for definition. The key caps are attached to the standard set with a strong adhesive.

Sharma has a team of student volunteers that help him build the keyboards and distribute them, and they have reached nearly 1,000 blind or visually-impaired students in the U.S. and abroad.

Got a hot tip that has like, anything to do with keyboards? Help me out by sending in a link or two. Don’t want all the Hackaday scribes to see it? Feel free to email me directly.