Devialet Phantom Ultimate 98 dB: An Audiophile Deep Dive

What kind of speaker is the Phantom Ultimate 98 dB?

The Phantom Ultimate 98 dB is a fully active wireless speaker in the Phantom II class, meaning every element of the signal chain lives inside a single sealed enclosure. There is no external amplifier, no preamp box, and no crossover component you need to source separately. When you feed it a digital or analog signal, the internal electronics handle conversion, filtering, amplification, and driver control as one integrated system. For an enthusiast, this matters because the entire chain is engineered as a matched whole. Devialet knows the exact impedance curve, excursion limits, and thermal behavior of the drivers it is driving, so the DSP and amplification can be tuned with a precision that separates rarely achieve. You trade the flexibility of mix and match components for a tightly optimized closed loop.

How does the ADH amplification work?

ADH stands for Analog Digital Hybrid, and it is Devialet's core amplification patent that marries a Class A voltage stage with high current Class D output stages. The idea is to let each topology do what it does best. A small Class A amplifier acts as the voltage reference and governs the sonic character, delivering the low noise and linearity that Class A is prized for. In parallel, Class D stages supply the heavy current demands of the bass drivers with the efficiency and thermal headroom that pure Class A could never sustain in a compact sealed box. The Class A stage effectively slaves the Class D stages to its output, correcting their behavior so the combined result tracks the clean analog reference. The practical payoff is that you get Class A grade signal purity paired with the power density needed to hit high SPL from a small cabinet without runaway heat.

Why is the enclosure sealed and pressurized?

The cabinet is a sealed, pressurized design rather than a ported one, and this is fundamental to how the Phantom controls its bass. A sealed enclosure has no port to resonate or produce chuffing noise, and it gives a more gradual low frequency rolloff with better transient control and tighter group delay than a typical vented box. The pressurized aspect refers to the internal air acting as a spring loaded against the woofers. Inside such a small volume the trapped air resists driver motion strongly, which normally would choke bass output, but Devialet compensates with enormous amplifier power and motor force to drive the cones against that pressure. The result is deep, controlled low end from a footprint that acoustics alone would say is impossible.

Drivers and Bass Mechanism

What drivers does the Phantom Ultimate use?

The Phantom Ultimate uses a front firing aluminum dome driver handling the mid and high frequencies, flanked by twin lateral aluminum bass drivers on the left and right cheeks of the enclosure. Aluminum is chosen for its high stiffness to mass ratio, which keeps the diaphragm rigid so it moves as a true piston without breaking up and adding coloration within its intended band. The front dome covers vocals, detail, and treble with a wide dispersion pattern, while the two side mounted woofers are mechanically opposed. Mounting the bass drivers on opposite sides means their reaction forces cancel each other out. Instead of the cabinet shaking and walking across your shelf during heavy bass, the momentum of one woofer counteracts the other, keeping the enclosure inert so the energy goes into the air rather than into vibrating the box.

What is Heart Bass Implosion (HBI)?

Heart Bass Implosion is Devialet's name for the mechanism that lets those twin lateral woofers generate deep bass with extreme excursion inside the tiny pressurized volume. The two drivers pulse inward and outward in perfect opposition, and the term implosion captures how they compress and release the sealed internal air like a heartbeat. Because the air pressure inside is so high, the motors and suspension must be built for large, controlled travel against significant resistance. HBI is the combination of that high excursion driver hardware, the pressurized sealing, and the DSP that commands the drivers precisely enough to keep distortion low even at full stroke. This is what allows a compact speaker to reach down into the deepest octaves with physical impact rather than a token nod at low frequencies.

How low and high does it actually play?

The frequency response reaches roughly from 18Hz at the bottom to 25kHz at the top. The 18Hz figure is the headline achievement, since that is genuinely subterranean territory that most standalone speakers, let alone ones this size, cannot approach without a dedicated subwoofer. Reaching down to 18Hz means the very lowest fundamentals of pipe organ, synthesizer bass, and cinematic low frequency effects are reproduced as felt energy rather than implied. At the top, 25kHz extends beyond the nominal limit of human hearing, giving headroom above the audible band so that the treble within our hearing range is reproduced without the phase and rolloff artifacts that can occur when a driver runs out of bandwidth right at 20kHz. Together this is a full range envelope from a single sealed cabinet.

What does Max SPL of 98dB at 1m tell you?

The 98dB maximum SPL at one meter is the loudness ceiling this particular Phantom II variant can deliver before its protection and processing rein it in. Ninety eight decibels at a meter is a substantial output that comfortably fills a normally sized living space and produces convincing dynamic peaks. This is where the 98 dB in the model name comes from, positioning it as a specific capability tier within the Phantom family. When interpreting this number, remember it is a peak measured at close range, so at a realistic listening distance of two to three meters the level at your ears will be lower due to distance attenuation. For most rooms it provides ample headroom, and pairing two units in stereo effectively raises the combined acoustic output for a bigger sound.

Signal Processing

What is SAM (Speaker Active Matching)?

Speaker Active Matching, or SAM, is Devialet's processing technology that models the physical behavior of the drivers and corrects the signal so the cone motion matches the original recorded waveform. Conventional speakers reproduce the electrical signal fed to them, but the resulting acoustic output is always shaped by the driver's mechanical characteristics. SAM works from a detailed model of exactly how these specific drivers respond, then it predicts and preemptively adjusts the drive signal so the actual air pressure produced follows the source signal faithfully, particularly in the demanding bass region. Because the Phantom is a closed active system, Devialet knows the drivers intimately and can apply this correction with confidence. The audible result is bass that stays tight and time accurate even as it reaches down to those low fundamentals, rather than the smearing that uncorrected drivers can introduce.

Connectivity and System Integration

What streaming protocols are supported?

The Phantom Ultimate streams over Wi-Fi using AirPlay 2, Spotify Connect, Roon Ready, and UPnP. This is a deliberately broad set that covers most ecosystems an enthusiast is likely to use. AirPlay 2 handles Apple devices and allows the Phantom to join a wider AirPlay multiroom system. Spotify Connect lets the Spotify app hand off playback directly to the speaker so your phone is only a remote. Roon Ready is the significant one for serious listeners, because it certifies the Phantom as a Roon endpoint that integrates into a Roon library with bit accurate streaming and full metadata. UPnP provides a standards based path for network media servers and third party control apps. Between them you have coverage for local network libraries and the major streaming services without extra hardware.

What physical network and wireless connections are there?

Connectivity comprises Wi-Fi, Bluetooth, and a Gigabit Ethernet port on an RJ-45 jack. Wi-Fi is the primary wireless link for streaming and multiroom, and Bluetooth gives you a quick, universal way to play from any phone or laptop without joining the network. The Gigabit Ethernet connection is the choice for the most stable, highest reliability setup. A wired RJ-45 link removes any dependence on Wi-Fi congestion or signal strength, which is valuable in dense apartment environments or when you are streaming high resolution material through Roon and want zero dropouts. Using Ethernet also frees Wi-Fi bandwidth for the rest of your household.

What wired inputs can you connect?

The wired inputs consist of a combination connector that serves as both a mini-optical (mini-TOSLINK) digital input and a 3.5mm analog minijack input. This single physical jack does double duty. Inserted with a mini-TOSLINK optical cable, it accepts a digital optical stream from a source such as a television or a CD transport with optical out. Inserted with a standard 3.5mm analog cable, it accepts a line level analog signal from a phone, a DAC, or a portable player. This is the extent of the physical audio inputs, so the design clearly expects network streaming to be the primary path, with this combination jack providing a fallback for local sources that are not on the network.

Are there any audio outputs?

The verified specification lists no audio outputs, which is consistent with the Phantom being a self contained active loudspeaker. Because the amplification, processing, and drivers are all internal, there is no reason to send a signal onward to external electronics. You are not connecting it to a separate amplifier or passing audio through to another device by wire. Any expansion to additional speakers happens over the network through the app rather than through a physical output jack.

Usage and Finish

How do you use it as mono, stereo, or multiroom?

You configure the Phantom as a single mono unit, as a stereo pair, or as part of a multiroom system entirely through the Devialet app. A single Phantom plays as a full range mono speaker. Adding a second unit lets the app assign one as the left channel and the other as the right for a true stereo image with proper channel separation and a wider soundstage. Beyond that, additional Phantoms placed in other rooms can be grouped for synchronized whole home playback or run independently. All of this routing and role assignment is software driven, so you can reconfigure the system without rewiring anything.

What is the Ultimate finish?

The Ultimate designation refers to the premium matte finish applied to this model. A matte surface treatment resists fingerprints and glare better than a high gloss shell and gives the sculpted enclosure a more understated, refined presence. It is a cosmetic distinction that marks this as a top tier variant within the Phantom line while the acoustic hardware and electronics do the heavy lifting behind it.