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Xcelsus
Xcelsus XU620 Ultra Series 6.5" Coaxial Set
SKU: XU620
$ 189.99
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Xcelsus XU620 Ultra Series 6.5" Coaxial Set
Regular price
$ 189.99
Sale price
$ 189.99
Regular price
$ 299.99
Unit price
Product Details
Specifications
Related Products
Xcelsus XU620 Ultra Series 6.5" Coaxial Speakers
High-Resolution Coaxial Matching XU Component Set Performance
ULTRA Series Dual 13mm Tweeters 75W RMS / 150W Max 92 dB Sensitivity 45-22,000 Hz Response DISCONTINUED NOS
Ultra Series: Bridging Coaxial and Component Performance
The Xcelsus XU620 Ultra series represents Dawid Koniarski's response to a specific customer demand: "We want a high-resolution coaxial speaker that could match the performance of other XU series component sets." While the Primum series XP620 demonstrated the dual tweeter innovation for factory upgrades, the XU620 Ultra elevates the concept with 50% more power handling (75W RMS vs. 50W RMS), significantly extended frequency response (45-22,000 Hz vs. 50-20,000 Hz), and enhanced component quality to approach the sonic excellence Dawid's XU component systems deliver.
These are brand new, factory-sealed New Old Stock (NOS) units from Audio Intensity's final inventory—never installed, never used, complete with original grilles. The XU620 Ultra has been discontinued alongside the entire Ultra series coaxial line as Xcelsus focuses on their highest-end offerings. Once this closeout inventory is exhausted, these high-resolution coaxials designed by the inventor of the component speaker system will be unavailable at any price.
Product Naming Clarification
Some retailers list these as "Primum XU620" due to packaging or labeling confusion. To be absolutely clear: XU620 is ULTRA series, not Primum. The model nomenclature follows Xcelsus's standard convention:
- XP prefix = Primum series (entry-level)
- XU prefix = Ultra series (mid-tier, high-resolution)
- XR prefix = Reference series (flagship)
The XU620 Ultra sits one tier above the XP620 Primum in Xcelsus's discontinued product hierarchy, offering enhanced specifications and performance that justify its positioning as a "high-resolution" coaxial designed to match component set standards.
Technical Specifications
| Specification | Value |
|---|---|
| Model | XU620 Ultra Series |
| Series | Ultra Series (DISCONTINUED) |
| Configuration | 2-Way Coaxial |
| Woofer Size | 6.5" (16.5 cm / 165mm) |
| Tweeter Configuration | Dual 13mm Mylar dome tweeters |
| Tweeter Mounting | Forward-mounted dual array |
| Woofer Cone Material | Polypropylene (enhanced formulation) |
| Power Handling (RMS) | 75W (50% more than XP620 Primum) |
| Power Handling (Max) | 150W peak (vs. 80W Primum) |
| Impedance | 4Ω (ohms) |
| Frequency Response | 45 Hz - 22,000 Hz (extended vs. Primum 50-20,000 Hz) |
| Sensitivity | 92 dB @ 1W/1m |
| Crossover Type | Integrated Mylar capacitor crossover |
| Crossover Slope | 6 dB/octave (first-order) |
| Mounting Hole Diameter | 145mm (5.7") |
| Mounting Depth | 52mm (2.0") - shallow mount |
| Grilles Included | Yes (speaker grilles included) |
| Condition | Brand New (Factory Sealed, New Old Stock) |
| Status | DISCONTINUED - Final Audio Intensity inventory |
XU620 Ultra vs. XP620 Primum: Understanding the Upgrade
Side-by-Side Specification Comparison
| Specification | XP620 Primum (Entry-Level) |
XU620 Ultra (High-Resolution) |
Advantage |
|---|---|---|---|
| Series | Primum | Ultra | — |
| Power RMS | 50W | 75W | +50% Ultra |
| Power Max | 80W | 150W | +87.5% Ultra |
| Frequency Low | 50 Hz | 45 Hz | +5 Hz extension Ultra |
| Frequency High | 20,000 Hz | 22,000 Hz | +2 kHz extension Ultra |
| Tweeter Size | Dual 16mm | Dual 13mm | Primum (larger) |
| Cone Material | Polypropylene + Mica | Polypropylene (enhanced) | Different formulations |
| Sensitivity | 92 dB | 92 dB | Equal |
| Mounting Depth | 52mm | 52mm | Equal |
| Grilles | No | Yes | Included Ultra |
Key Differentiators Explained
50% Higher Power Handling
The XU620's 75W RMS rating (vs. XP620's 50W) allows pairing with more powerful amplifiers or high-output head units without risk of thermal damage. This extra headroom means cleaner dynamics during musical peaks and greater output potential for enthusiasts seeking serious volume.
Extended Frequency Response
The 45-22,000 Hz range (vs. XP620's 50-20,000 Hz) provides deeper bass extension (critical for midbass punch) and extended treble response (improved "air" and spatial cues). These 7 Hz extensions represent measurable improvements in perceived low-end impact and high-end sparkle.
Enhanced Component Quality
While both use dual tweeter arrays and polypropylene cones, the Ultra series benefits from tighter manufacturing tolerances, selected-grade components, and enhanced materials formulations that Xcelsus reserves for mid-tier and higher products.
Included Grilles
The XU620 includes protective grilles as standard equipment (XP620 does not), adding practical value and aesthetic polish for installations where factory grilles aren't present or adequate. A small detail that reflects Ultra series attention to complete packaging.
Who Should Choose XU620 Ultra Over XP620 Primum?
- Amplified Systems: If you're planning to use an external amplifier delivering 50-75W RMS per channel, the XU620's higher power handling is essential to utilize that amplifier capability safely
- Bass Enthusiasts: The 45 Hz low-frequency extension provides noticeably deeper midbass impact compared to the XP620's 50 Hz limit—important for hip-hop, EDM, and bass-heavy genres
- Audiophile Listeners: The extended 22 kHz treble response and enhanced component quality deliver refinements that critical listeners will appreciate in complex, well-recorded music
- Future-Proofing: Higher power handling allows system upgrades (more powerful amplifier) without needing to replace speakers again
Budget Consideration: If budget is tight and you're running factory head unit power only (15-22W RMS), the XP620 Primum may suffice. However, the XU620's extended frequency response and included grilles provide value even at factory power levels, making it the better long-term investment if price difference is modest.
Dual 13mm Tweeter Array: Refined Implementation
13mm vs. 16mm Tweeter Size Strategy
Interestingly, the higher-tier XU620 Ultra uses smaller 13mm tweeters compared to the XP620 Primum's 16mm units. This isn't a cost-cutting measure—it's deliberate engineering for specific sonic characteristics:
Extended High-Frequency Response
Smaller dome diameters reach higher frequencies before directivity narrowing and breakup modes occur. The 13mm domes contribute to the XU620's 22 kHz extension (vs. XP620's 20 kHz), providing enhanced "air" and spatial information that audiophiles value.
Reduced Mass, Faster Transients
13mm domes have approximately 30% less moving mass than 16mm domes, allowing faster acceleration and deceleration in response to transient signals. This improves reproduction of cymbal crashes, hi-hat sizzle, and other high-frequency transient content.
Dual Configuration Maintains Output
While individual 13mm tweeters produce less output than 16mm units, the XU620 still uses two tweeters in coherent array configuration. The dual arrangement maintains adequate high-frequency output despite smaller individual dome size.
Quality Over Size
The Ultra series likely uses higher-grade Mylar film, tighter manufacturing tolerances, and more sophisticated magnet systems in the 13mm tweeters compared to the Primum series 16mm units—quality trumping pure size in the audio hierarchy.
Forward-Mounted Array: Factory Location Optimization
Like the XP620 Primum, the XU620 Ultra employs forward-mounted dual tweeter array configuration—Dawid's solution to modern vehicles mounting speakers deep behind door panels and trim that severely attenuate high frequencies. The dual array overcomes door panel absorption through:
- Doubled Acoustic Output: Two tweeters radiating coherently produce approximately +3 dB more output than single tweeter designs
- Improved Directionality: Array pattern focuses treble energy forward toward listeners rather than dispersing into door panel cavities
- Redundancy: If one tweeter's path is partially obstructed by door grilles or interior trim, the second maintains treble presence
This makes the XU620 ideal for factory location upgrades where component speakers with external tweeters aren't practical or desired. The coaxial format simplifies installation while the dual tweeter array ensures treble presence despite challenging mounting conditions.
45-22,000 Hz Response: Extended Bandwidth Advantage
Low-Frequency Extension: 45 Hz vs. 50 Hz
The XU620's 45 Hz low-frequency extension provides 5 Hz deeper bass response compared to the XP620 Primum's 50 Hz specification. While 5 Hz might seem modest, it represents approximately 10% deeper extension into the critical midbass region:
- Kick Drum Fundamentals: Many kick drums have fundamental frequencies in the 45-60 Hz range. The XU620's 45 Hz extension captures more of this fundamental energy, providing fuller, more impactful kick drum reproduction
- Bass Guitar Low Notes: The low E string on a bass guitar produces 41 Hz. The XU620's 45 Hz extension approaches this frequency, providing better definition on bass guitar lines compared to the XP620's 50 Hz rolloff
- Subwoofer Integration: If you're running a subwoofer system with crossover at 80 Hz, the XU620's deeper extension creates better overlap in the 45-80 Hz transition region, ensuring smooth frequency response without gaps
High-Frequency Extension: 22,000 Hz vs. 20,000 Hz
The 22 kHz high-frequency extension (vs. XP620's 20 kHz) provides 2 kHz additional treble response. While most adults can't hear above 16-18 kHz due to age-related hearing loss, the extended response matters for several reasons:
- Harmonic Content: Even if the fundamental tone is inaudible, harmonics and overtones extending to 22 kHz influence perceived timbre and "air" in the upper treble range
- Phase Coherence: Drivers with extended high-frequency response typically maintain better phase linearity through the audible range (up to 15-16 kHz where most people actually hear), improving transient accuracy
- Younger Listeners: Children and young adults can hear to 18-20 kHz. The XU620's 22 kHz extension ensures full-range reproduction for listeners with excellent high-frequency hearing
- Hi-Res Audio Compatibility: High-resolution audio formats (24-bit/96kHz, 192kHz) contain ultrasonic content. While debatable whether humans perceive it directly, the XU620 can reproduce it if present in source material
75W RMS Power Handling: Amplifier-Ready Performance
Power Scaling: From Factory to Amplified
The XU620's 75W RMS continuous power handling (150W max peaks) positions it perfectly for various system configurations:
Factory Head Unit (15-22W RMS)
Running the XU620 on factory power leaves massive headroom—the speakers will never approach thermal or mechanical limits. This ensures low-distortion operation even at maximum factory volume, with potential for future amplifier upgrade without speaker replacement.
Aftermarket Head Unit (22-30W RMS)
High-power aftermarket head units still operate well within the XU620's capability. The 92 dB sensitivity means 30W input produces ~107 dB output—plenty loud for most listening while maintaining clean, unstressed performance.
Entry-Level Amplifier (50-75W RMS)
This is the XU620's sweet spot. A 50W×4 or 75W×4 amplifier can drive the XU620 to its full rated output, achieving maximum clean SPL (approximately 110-111 dB) without risk of damage. Perfect match for enthusiasts seeking serious performance.
High-Power Amplifier (100-150W RMS)
With careful gain setting, the XU620 can handle brief peaks from powerful amplifiers. However, sustained operation above 75W RMS risks thermal damage. Use amplifier gain controls to limit output to safe 75W maximum.
92 dB Sensitivity: Efficiency Matters
Like the XP620 Primum, the XU620 Ultra maintains 92 dB sensitivity—excellent efficiency that allows impressive output from modest power. At the rated 75W RMS input:
- Maximum SPL: ~110.8 dB at 1 meter distance
- Typical Listening: 20-30W average achieves 105-107 dB—loud, impactful, dynamic
- Amplifier Efficiency: High sensitivity reduces amplifier power requirements, allowing smaller, cooler-running amplifiers
Installation & Vehicle Compatibility
Universal 6.5" Fitment
| Dimension | Measurement | Compatibility Note |
|---|---|---|
| Mounting Hole | 145mm (5.7") | Standard 6.5" cutout—fits most factory locations |
| Mounting Depth | 52mm (2.0") | Shallow mount—clears nearly all door panels |
The XU620's standard dimensions ensure compatibility with the vast majority of vehicles using 6.5" factory speakers in doors, rear decks, kick panels, or dash locations.
Grilles Included: Installation Convenience
Unlike the XP620 Primum, the XU620 Ultra includes protective grilles as standard equipment. These grilles serve multiple purposes:
- Cone Protection: Safeguards polypropylene cone from accidental contact during vehicle entry/exit or cargo loading
- Aesthetic Finish: Provides professional appearance in installations where factory grilles aren't present or adequate
- Dust Prevention: Reduces dust accumulation on cone and tweeter surfaces in daily driving conditions
Factory vs. Aftermarket Integration
- Factory Head Unit Upgrade: Direct speaker replacement with factory wiring—maintains steering wheel controls, factory integration, simplified installation
- Aftermarket Head Unit: Pair XU620 with aftermarket head unit (22-30W RMS) for improved source quality and increased output without amplifier investment
- Amplified System: Run XU620 with dedicated 4-channel amplifier (50-75W×4) for maximum performance—requires amplifier installation, gain setting, professional wiring
New Old Stock from Audio Intensity: Ultra Series Closeout
Discontinued Alongside Entire Ultra Coaxial Line
The XU620 Ultra has been discontinued as part of Xcelsus's broader decision to discontinue all Ultra series coaxial speakers. While Ultra series component speakers remain in production (XU6.2C and similar models continue as current products), Xcelsus chose to exit the coaxial market above the Primum tier.
This strategic shift reflects the reality that serious enthusiasts—the target market for Ultra series—typically prefer component speakers where separate tweeters can be mounted for optimal staging and imaging. Coaxials, even high-resolution designs like the XU620, inherently limit tweeter placement to cone center, compromising staging potential compared to components.
For Xcelsus, continuing the Ultra coaxial line didn't make business sense when the same target customers would choose Ultra components given the option. The XU620 represents the final expression of Dawid's high-resolution coaxial design before Xcelsus focused exclusively on component speakers at the Ultra tier and above.
Audio Intensity Final Inventory
These XU620 Ultra speakers are New Old Stock from Audio Intensity's remaining inventory:
- Brand New Condition: Factory sealed, never installed, never used, complete with grilles
- Xcelsus Discontinued: Xcelsus will not produce additional Ultra series coaxials—ever
- Audio Intensity Closeout: Once current NOS inventory sells, no restock possible at any price
- Last Opportunity: Final chance to purchase brand new Dawid-designed high-resolution coaxials
Why This Matters for Buyers
The XU620 Ultra occupies a unique position in Xcelsus history: the only high-resolution coaxial Dawid Koniarski ever designed. The Primum series XP620 was entry-level; the Reference and Ultra component speakers are current flagship products. But the XU620 Ultra—a genuine high-resolution coaxial with extended frequency response and serious power handling—was produced for a limited time before strategic discontinuation.
For enthusiasts who prefer coaxial simplicity but want performance approaching component quality, this NOS inventory represents the last opportunity to purchase Dawid's only venture into high-resolution coaxial design. It's not coming back.
High-Resolution Coaxial Excellence at Closeout Pricing
When customers demanded "a high-resolution coaxial that could match the performance of XU component sets," Dawid Koniarski designed the XU620 Ultra. Extended 45-22,000 Hz frequency response for deeper bass and extended treble. 75W RMS power handling (50% more than Primum XP620) for serious amplified systems. Dual 13mm Mylar tweeter array optimized for factory location treble clarity. Enhanced component quality reflecting Ultra series standards.
This is brand new New Old Stock from Audio Intensity's final inventory. Factory sealed with included grilles. Xcelsus has permanently discontinued all Ultra series coaxials—the XU620 represents the final evolution of Dawid's high-resolution coaxial design before strategic focus shifted exclusively to component speakers at this performance tier.
Once Audio Intensity's NOS stock sells, the XU620 Ultra is gone forever. No restock. No reproduction. No second chances. This is the only high-resolution coaxial Dawid ever designed—a unique position in Xcelsus history now relegated to discontinued status.
Upgrade from factory speakers with genuine high-resolution performance. Approach component speaker quality in coaxial convenience. Own the final expression of Dawid's high-resolution coaxial philosophy.
New Old Stock. Ultra Series. High-Resolution Coaxial. Discontinued Forever.
