Xcelsus XPLM6 – PRIMUM Series SQL Midbass/Midrange
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Xcelsus XPLM6 Primum SQL Midbass/Midrange
Sound Quality + Loudness: Dawid Koniarski's Affordable SQL Driver
SQL Philosophy: Sound Quality + Loudness
The Xcelsus XPLM6 Primum represents Dawid Koniarski's entry into the SQL (Sound Quality + Loudness) category—a competitive class that demands exceptional sonic characteristics while maintaining the ability to play clean at extreme volume levels. This discontinued driver from the Primum series showcases Dawid's 40+ years of design expertise applied to the challenge of creating an affordable midbass/midrange that refuses to compromise between accuracy and output.
These are brand new, factory-sealed units from Audio Intensity's remaining stock—never installed, never used, complete with original grilles and accessories. Once this New Old Stock (NOS) inventory is exhausted, the XPLM6 Primum will be gone forever, replaced by Xcelsus's higher-end series where Dawid's legendary design reputation commands premium pricing.
The SQL Challenge: Competing Priorities
Traditional car audio competition divides into two camps: Sound Quality (SQ) competitions judge subjective listening experience, tonal accuracy, imaging, and staging, while SPL (Sound Pressure Level) competitions measure pure volume with decibel meters. SQL competitions demand both simultaneously—drivers must deliver audiophile-level sound quality while generating competition-level output.
This creates engineering tension. SQ-oriented drivers prioritize low distortion, smooth frequency response, and controlled directivity—often at the expense of maximum SPL capability. SPL-oriented drivers prioritize maximum cone area, excursion, and power handling—often at the expense of linearity and tonal accuracy. SQL drivers must excel at both.
The XPLM6 Primum solves this through specific design choices:
- Lightweight Non-Pressed Paper Cone: Provides low mass for transient speed and natural tonal character (SQ priority) while maintaining rigidity for high excursion without cone breakup (loudness priority)
- Oversized 130mm Magnet System: Delivers massive control authority for accurate bass reproduction (SQ priority) while enabling high power handling and output (loudness priority)
- 38mm Voice Coil with Integrated Cooling: Large diameter increases power handling and thermal capacity (loudness priority) while maintaining linear excursion range for distortion-free reproduction (SQ priority)
- Bullet-Contoured Phase Plug + Copper Shorting Cap: Controls high-frequency response and reduces cone breakup coloration (SQ priority) while improving thermal dissipation and voice coil control (loudness priority)
Primum Series Positioning
Within Xcelsus's product hierarchy, the Primum series represented the entry point to Dawid's design philosophy—affordable drivers that demonstrated his engineering approach without the exotic materials and hand-tuned tolerances of the Ultra SQL or Reference series. The XPLM6 showcased what careful driver topology and motor design could achieve even at accessible price points.
Xcelsus discontinued the Primum series to focus resources on higher-margin products where Dawid's reputation as the inventor of the component speaker system justifies premium pricing. This creates exceptional value: drivers designed by a legend, engineered for SQL competition, priced as discontinued closeout inventory.
Technical Specifications
| Specification | Value |
|---|---|
| Model | XPLM6 Primum SQL |
| Series | Primum Series (DISCONTINUED) |
| Application | Midbass / Midrange Driver (SQL Competition) |
| Driver Size | 6.5" (16.5 cm / 165mm) |
| Cone Material | Lightweight, high-quality non-pressed paper |
| Phase Plug | Bullet-contoured design |
| Voice Coil Diameter | 38mm (1.5") high-temperature |
| Voice Coil Cooling | Integrated air-cooling system |
| Magnet System | Oversized 130mm (5.1") diameter |
| Motor Enhancement | Copper shorting cap (reduced inductance) |
| Power Handling (RMS) | 125W continuous |
| Power Handling (Max) | 300W peak |
| Impedance | 4Ω (ohms) |
| Sensitivity | 94 dB @ 1W/1m |
| Frequency Response | 80 Hz - 7,000 Hz (operating range) |
| Optimal Crossover Range | 80-100 Hz high-pass, 3000-5000 Hz low-pass |
| Outer Diameter | 200mm (6.5" / 7.9") |
| Mounting Hole Diameter | 144mm (5.7") |
| Mounting Depth | 71mm (2.8") |
| Grilles Included | Yes (protective grilles included) |
| Recommended Pairing | Xcelsus XPLT28W waveguide tweeter (sold separately) |
| Condition | Brand New (Factory Sealed, New Old Stock) |
| Status | DISCONTINUED - Limited remaining Audio Intensity inventory |
Non-Pressed Paper Cone: Natural Tonal Accuracy
The Paper Cone Advantage
In an era dominated by exotic synthetic materials—Kevlar, carbon fiber, aluminum, polypropylene—Dawid's choice of non-pressed paper for the XPLM6 cone represents deliberate adherence to proven acoustic principles. Paper has been the material of choice for audiophile loudspeakers since the earliest days of high-fidelity reproduction, and for good reasons:
Natural Damping
Paper's fibrous structure provides inherent mechanical damping that dissipates vibrational energy as heat. This internal damping suppresses cone breakup modes and resonances that color midrange response, resulting in smooth, natural tonal character without the metallic edge of aluminum or the plasticky timbre of some synthetics.
Optimal Stiffness-to-Mass Ratio
High-quality paper achieves excellent stiffness (resisting flexure under bass pressure) while maintaining low mass (responding quickly to transient signals). This balance allows the XPLM6 to reproduce punchy midbass kick drums while maintaining the speed necessary for detailed midrange vocals and instruments.
Predictable Breakup Behavior
All cone materials eventually reach frequencies where bending waves travel across the cone surface (breakup modes). Paper's predictable breakup behavior allows Dawid to design around these modes, pushing them above the driver's operating range or controlling them through geometric cone shaping and phase plug design.
Manufacturing Consistency
Modern paper cone manufacturing using precision molds and controlled pulp mixtures produces highly consistent mechanical properties from unit to unit—critical for left/right channel matching in stereo imaging and multi-driver arrays in SQL competition systems.
Non-Pressed vs. Pressed Paper
The XPLM6 specifies "non-pressed" paper—a distinction that matters significantly:
- Pressed Paper Cones: Created by pressing paper pulp into a mold under high temperature and pressure, increasing density and stiffness but often creating uneven density distribution and internal stresses that can cause non-linear behavior
- Non-Pressed Paper Cones: Formed through lower-pressure molding processes that maintain more uniform fiber orientation and density distribution, resulting in more linear mechanical behavior and predictable acoustic performance
The trade-off is manufacturing cost—non-pressed paper requires more sophisticated process control and longer cure times. Xcelsus's willingness to use non-pressed paper even in the affordable Primum series demonstrates Dawid's commitment to prioritizing sonic performance over cost reduction.
Lightweight Design Philosophy
Dawid describes the XPLM6 cone as "lightweight" specifically—a characteristic that directly impacts SQL performance:
- Transient Response: Lower moving mass (cone + voice coil + former) allows faster acceleration and deceleration in response to signal changes, improving reproduction of percussion, plucked strings, and other transient-rich musical content
- Efficiency: The 94 dB sensitivity rating partly results from lightweight cone design—less mass means more acoustic output for a given electrical input power
- Power Handling: While counterintuitive, lightweight cones can handle high power when paired with appropriate suspension and voice coil design. The key is maintaining linear excursion range, which the XPLM6 achieves through oversized magnet control authority
Oversized Motor System: Control Authority
130mm Magnet: Massive for 6.5" Class
The XPLM6's 130mm (5.1") diameter magnet is genuinely oversized for a 6.5" driver. For context, typical 6.5" coaxials and component woofers use 70-90mm magnets; budget drivers often use 50-60mm magnets. The XPLM6's 130mm magnet represents approximately 2-3× the magnet mass of typical competitors.
Why Oversized Magnets Matter:
Magnetic Flux Density
Larger magnets generate stronger magnetic fields in the voice coil gap, increasing motor force factor (BL product). Higher BL translates to greater control authority over cone motion, reducing distortion and improving transient accuracy—critical for SQL sound quality.
Reduced Compression
Oversized magnets maintain stronger magnetic field even as voice coil heats up during high-power operation. Smaller magnets suffer thermal modulation (reduced output as voice coil resistance increases with heat). The 130mm magnet keeps the XPLM6 playing loud without compression—critical for SQL loudness.
Extended Linear Excursion
Large magnets allow longer voice coil wind heights within the gap, maintaining linearity through greater excursion ranges. This enables high output SPL without voice coil leaving the gap (which causes severe distortion and potential damage).
Improved Damping Factor
Strong magnetic fields increase electrical damping (motional feedback), controlling cone resonances and improving transient response. This contributes to the tight, controlled midbass that SQL judges listen for when evaluating driver performance.
Copper Shorting Cap: Inductance Reduction
The XPLM6 incorporates a copper shorting cap (shorting ring) attached to the pole piece—a feature typically found only in higher-end drivers. This copper ring serves critical functions:
- Reduced Voice Coil Inductance: The voice coil acts as an inductor whose impedance rises with frequency, reducing high-frequency output. The copper shorting cap's eddy currents oppose this inductance rise, flattening impedance through the midrange and extending smooth response
- Lower Distortion: Voice coil inductance causes non-linear behavior that generates distortion products. Reducing inductance through the shorting cap lowers distortion, particularly in the critical 1-3 kHz midrange where human hearing is most sensitive
- Improved Transient Response: Lower inductance reduces electrical time constants, allowing faster current changes through the voice coil and improving transient reproduction accuracy
- Thermal Dissipation: The copper cap provides additional thermal mass and conduction path, helping dissipate heat from the voice coil gap during high-power operation
38mm Voice Coil: Power + Control
The XPLM6's 38mm (1.5") diameter voice coil represents substantial size for a 6.5" driver (many use 25-32mm coils). Larger voice coils provide several advantages:
- Increased Power Handling: Larger coil diameter means more wire surface area for heat dissipation, enabling the 125W RMS / 300W max power ratings without thermal failure
- Greater Mechanical Stability: Larger diameter provides better resistance to rocking modes (voice coil tilting in the gap), maintaining proper gap clearance during high-excursion bass reproduction
- Improved Motor Force Linearity: Larger coils allow longer wind heights that can remain within the gap through greater excursion ranges, maintaining linear BL product through the driver's full dynamic range
The integrated air-cooling system enhances thermal management further. While details aren't specified, typical implementations include vented pole pieces, vented voice coil formers, or optimized air gaps that promote convective airflow through the magnetic structure as the cone moves. This forced-air cooling allows sustained high-power operation without thermal compression—critical for SQL competition use.
Bullet-Contoured Phase Plug: Acoustic Refinement
Phase Plug Functions
The XPLM6's bullet-contoured phase plug mounted at cone center serves multiple acoustic functions:
High-Frequency Extension
At high frequencies, the cone center becomes acoustically large (wavelength comparable to cone dimensions), causing directivity narrowing and response irregularities. The phase plug acts as a high-frequency source from the cone center, extending smooth response through the midrange into the lower treble range (up to 7 kHz operating limit).
Cone Breakup Control
The rigid phase plug mass-loads the cone center, increasing stiffness in the region most prone to bending modes. This pushes cone breakup frequencies higher, maintaining piston-like motion through more of the driver's operating range.
Improved Directivity
The bullet contour shape guides high-frequency sound waves forward, improving on-axis response and controlling off-axis rolloff characteristics. This helps maintain consistent tonal balance in the difficult acoustic environment of car interiors where reflections dominate.
Reduced Cavity Resonances
Without a phase plug, the dust cap cavity can create resonances that color midrange response. The bullet-contoured phase plug eliminates or dampes these cavity modes, contributing to the smooth, natural tonal character essential for SQL sound quality.
80-7,000 Hz Operating Range
The XPLM6's 80 Hz - 7,000 Hz operating range positions it as a true midbass/midrange driver covering the bulk of musical content:
- 80 Hz High-Pass: Protects the driver from subwoofer-range content where 6.5" drivers lack displacement capability, while covering the critical 80-250 Hz midbass "impact zone" responsible for kick drums, bass guitars, and musical punch
- 7,000 Hz Low-Pass: Extends into lower treble territory unusual for 6.5" drivers (many roll off by 3-5 kHz), reducing the burden on tweeters and creating smoother crossover transitions. The bullet phase plug enables this extension
- Midrange Coverage: The 250-3,000 Hz midrange range contains vocals, most acoustic instruments, and the frequencies where human hearing is most sensitive—the XPLM6's paper cone and phase plug design prioritize accuracy in this critical region
Recommended Pairing: XPLT28W Waveguide Tweeter
Xcelsus specifically recommends pairing the XPLM6 with their XPLT28W waveguide tweeter, stating this combination "affordably delivers HiFi quality sound experience at extreme volume levels." The waveguide tweeter's controlled directivity matches the XPLM6's pattern, creating seamless polar response integration essential for SQL competition where judges evaluate off-axis listening positions as well as on-axis response.
SQL Competition Applications
Understanding SQL Competition Requirements
SQL (Sound Quality + Loudness) competitions present unique challenges compared to pure SQ or SPL events:
- Sound Quality Judging: Subjective listening evaluation includes tonal accuracy, imaging precision, soundstage depth/width, and absence of distortion or coloration—identical to pure SQ competitions
- SPL Measurement: Objective decibel meter readings at specified frequencies (typically 80 Hz, 160 Hz, 315 Hz, 630 Hz, 1250 Hz, 2500 Hz, 5000 Hz, 10000 Hz) with minimum thresholds required for each class
- Balanced Scoring: Final scores combine subjective and objective elements, rewarding systems that achieve both audiophile sound quality and competition-level output
The XPLM6 addresses both requirements through design choices that refuse to sacrifice one priority for the other.
System Configuration Recommendations
Active 2-Way Front Stage
Configuration: XPLM6 midbass + XPLT28W tweeter, active crossover via DSP
Crossover: 80-100 Hz high-pass on XPLM6, 3000-4000 Hz crossover point, 24 dB/octave Linkwitz-Riley
Benefit: Maximum control over frequency response and time alignment, essential for competition-level imaging precision
Active 3-Way Front Stage
Configuration: XPLM6 midbass (80-500 Hz) + dedicated midrange (500-3000 Hz) + tweeter (3000+ Hz)
Benefit: Allows XPLM6 to focus exclusively on midbass impact zone where its large motor and paper cone excel, while dedicated midrange handles critical vocal range with minimal excursion
Multi-Driver Midbass Array
Configuration: Dual or triple XPLM6 drivers per side in kick panels or door locations
Benefit: Multiple 6.5" drivers sum acoustically for +3 dB (dual) or +4.8 dB (triple) output increase, reaching SQL SPL thresholds while distributing power across multiple voice coils for thermal management
High-Power Amplification
Requirement: 100-150W RMS per XPLM6 driver
Benefit: Utilize full 125W RMS rating with headroom, ensuring amplifier never strains during dynamic peaks. Reduced amplifier distortion improves SQ scores while maximum driver output capability improves SPL scores
Installation Considerations for SQL
- Kick Panel Mounting: Ideal for XPLM6 midbass—direct path to listeners, minimal reflections, ability to mount drivers aimed at listening positions for optimized soundstage
- Door Mounting: Requires extensive sound-deadening (CLD tiles, foam, mass-loaded vinyl) to eliminate panel resonances that judges penalize. Vapor barrier behind driver creates proper rear chamber for bass response
- Enclosures: XPLM6 can operate in sealed or infinite baffle (IB) configurations. Sealed provides tighter bass control and predictable response; IB provides slightly higher efficiency but requires proper rear-wave management
- Amplifier Selection: Choose amplifiers with excellent signal-to-noise ratio (>100 dB), low distortion (<0.05% THD), and high damping factor (>200) to maintain XPLM6's inherent accuracy
- Signal Processing: High-quality DSP (like Goldhorn DSPA 810 Pro, AudioControl, Helix) essential for precise crossover slopes, time alignment correction, and EQ optimization without degrading source signal quality
Installation & Vehicle Compatibility
Mounting Dimensions
| Dimension | Measurement | Compatibility Note |
|---|---|---|
| Outer Diameter | 200mm (7.9") | Larger than standard 6.5" speakers—measure clearance |
| Mounting Hole | 144mm (5.7") | Standard 6.5" cutout diameter |
| Mounting Depth | 71mm (2.8") | Moderate depth—check door panel clearance |
Important: The XPLM6's 200mm outer diameter is larger than typical 6.5" drivers (usually 165-175mm). Verify adequate clearance in door panel or mounting location, particularly in vehicles with limited space between speaker mounting surface and interior trim.
Power Requirements
The XPLM6's 125W RMS / 300W max power handling requires appropriate amplification:
- Minimum Recommended: 75-100W RMS per channel (moderate listening levels, non-competition use)
- Optimal SQL Competition: 125-150W RMS per channel (full driver capability, headroom for dynamic peaks)
- Maximum Safe: 175W RMS per channel (brief peaks only—sustained power above 125W risks thermal damage)
The 94 dB sensitivity means 125W RMS input produces approximately 115 dB maximum SPL at 1 meter—sufficient for SQL competition SPL requirements in the critical midbass frequencies when combined with proper vehicle tuning and subwoofer support.
Grilles Included
The XPLM6 includes protective grilles—a practical consideration for door-mounted installations where interior trim grilles may not provide adequate protection. These grilles safeguard the lightweight paper cone from accidental contact during vehicle entry/exit or cargo loading, while providing professional finished appearance.
New Old Stock from Audio Intensity: Final Opportunity
What This Means
These XPLM6 Primum drivers are New Old Stock (NOS) from Audio Intensity, meaning:
- Brand New Condition: Never installed, never used, never opened—factory sealed with all original accessories including grilles
- Audio Intensity Inventory: Final remaining units from Audio Intensity's stock of discontinued Xcelsus Primum series
- Xcelsus Discontinued: Xcelsus has permanently discontinued the Primum series, focusing on higher-end Ultra SQL and Reference lines
- No Future Availability: Once Audio Intensity's NOS inventory is exhausted, the XPLM6 will be unavailable—no restock, no reproduction, ever
Why Discontinued?
Xcelsus discontinued the Primum series (including XP620 coaxials and XPLM6 midbass) as part of brand repositioning toward premium markets. Dawid Koniarski's reputation as the inventor of the component speaker system and 40+ years of design experience command higher price points in the Ultra SQL and Reference series where exotic materials, hand-tuned tolerances, and limited production runs justify premium positioning.
The Primum series represented Xcelsus's entry-level offering—genuinely designed by Dawid with his characteristic attention to driver topology and motor optimization, but using more cost-effective materials (paper cones vs. carbon fiber, standard magnets vs. neodymium) to reach accessible price points.
Discontinuation doesn't reflect performance deficiencies. Rather, it's a business decision to maximize Dawid's design time on products where his legendary status justifies higher margins. For buyers, this creates exceptional value: SQL-capable drivers designed by an industry legend, priced as closeout inventory.
Collectibility & Historical Context
Beyond their SQL performance capabilities, XPLM6 drivers represent a specific moment in car audio history: Dawid Koniarski's final affordable SQL design before Xcelsus focused exclusively on premium products. As the inventor of the component speaker system (1983) transitions fully to high-end markets, these entry-level NOS units become the last affordable access to his design philosophy.
For collectors, competitors, and enthusiasts who appreciate the lineage behind their equipment, NOS XPLM6 drivers represent the last chance to own Dawid-designed SQL drivers at closeout pricing rather than the premium commanded by his current-generation products.
Audio Intensity Final Inventory
These are the absolute final units from Audio Intensity's inventory of discontinued Xcelsus Primum products. Audio Intensity has confirmed:
- No additional XPLM6 stock will be acquired
- Xcelsus will not produce additional Primum series units
- Once current NOS inventory sells, the XPLM6 is gone forever
- This represents the last opportunity to purchase brand new units at any price
Act now—this opportunity will not return.
SQL Excellence at Closeout Pricing
In SQL competition, compromise means defeat. Systems must deliver audiophile sound quality while generating competition-level output—requirements that eliminate 90% of drivers as unsuitable for either SQ or loudness priorities. The Xcelsus XPLM6 Primum refuses compromise through deliberate engineering: lightweight non-pressed paper cone for natural tonal accuracy, oversized 130mm magnet for control authority, 38mm voice coil with integrated cooling for power handling, bullet-contoured phase plug with copper shorting cap for extended response.
This is Dawid Koniarski's SQL philosophy made affordable—the same design approach that dominated IASCA and EMMA championships worldwide, applied to the Primum series before Xcelsus discontinued the entry-level line. Brand new, factory-sealed drivers from Audio Intensity's final NOS inventory. 125W RMS power handling, 94 dB efficiency, 80-7,000 Hz response covering vocals through midbass impact. Protective grilles included.
This is discontinued inventory—once Audio Intensity's NOS stock sells, the XPLM6 Primum is gone forever. Xcelsus has permanently discontinued the Primum series, focusing on premium products where Dawid's legendary reputation justifies higher pricing. No restock. No reproduction. No second chances.
Build your SQL competition system with drivers designed by the inventor of the component speaker. Experience the sound quality + loudness philosophy that earned championships on every continent. Own a piece of car audio history before it disappears.
New Old Stock. Discontinued Forever. SQL Performance at Entry-Level Pricing.
Xcelsus XPLM6 – PRIMUM Series SQL Midbass/Midrange
Frequently Asked Questions
Are these items authentic, and why are the prices so low?
This sale includes demo units we've used for customer demonstrations since 2016, new-old-stock from discontinued product lines, display models from trade shows, and carefully curated inventory we've collected over nearly a decade. Most items include original packaging where available.
What types of items are included in the relocation sale?
Our relocation sale includes demo units we've used for customer demonstrations, new old stock from discontinued product lines, and display models from trade shows. All items are genuine products from top car audio brands - we're simply clearing inventory we can't take to our new location. Items range from amplifiers and speakers to processors and accessories accumulated over nearly 10 years at this location.
Do sale items come with manufacturer warranties?
Warranty coverage varies by item and condition. New old stock items typically include full manufacturer warranty if still valid. Demo and display items may have limited or no manufacturer warranty remaining. We clearly state warranty status in each product description. All sales are final on relocation sale items.
How does shipping work for relocation sale items?
We ship relocation sale items using the same careful packaging methods as our regular inventory. Shipping costs are calculated at checkout based on size and weight. For multiple item purchases, we'll combine shipping where possible to save you money. Large items like subwoofer boxes may require freight shipping with additional costs.
Can I return or exchange relocation sale items?
All relocation sale items are sold as-is with no returns or exchanges. We encourage local pickup customers to inspect items before purchasing. For shipped items, we provide detailed descriptions and photos. Since we're relocating, we cannot accommodate returns or warranty service after the sale period ends.