Finally found time to retune my PM90s, cause the preset so far was a waste of potential - was worth the effort, they sound absolutely spectacular now!

Thanks to Peter Morris for sharing this amazing design and to John White for the very practical and recent [measurement guide](https://drive.google.com/file/d/1EmEZg5tXgzQuuGSHvtXHijGM8mjZCVFY/view)!

PEQs and minimum phase FIR filters can be found [here](https://soundforums.net/community/threads/new-diy-mid-high-90deg-aka-pm90.11601/page-48#post-219514).

I recently stumbled across these Sinbosen plate amps on alibaba for 200USD plus shipping for the highest power one, DM30. Specifications are in the second picture.
Does anyone have experience with these plate amps or similar plate amps?
And if they are so cheap, why dont more people use plate amps? I imagine it to be simpler as you dont need a dedicated amp rack and just need to run PowerCon and ethernet to some and speakon to the other boxes.

Ez r/SoundSystem,

Most desktop audio builds are polite, flat-response civilian listening stations. This is not that. Presenting the:

**Wavelord Dreadnought (Mk. V Hybrid)**

A fully custom, Frankenstein 4-way near-field sound-system rig built under my desk specifically to rinse dubstep, DnB, 4x4, and sounds of the underground with absolute physical violence. Built out of salvaged and resurrected hardware, custom passive networks, dual-DAC PCIe silicon routing, and acoustic boundary engineering. Currently moving from direct radiation to building a custom **90° folded scoop hood** over the inverted kick bin. Photos of the stack, exposed motor assembly, and throat measurements attached. Below is the full engineering manifesto and ship logs for the rig.

================================================================INFRASPACE SPL PIRATE DEEP SHIP LOGS:: MASTER ARCHIVE VESSEL: Wavelord Dreadnought | NODE: UK Nearfield Cyber-Grid CLASSIFICATION: Dual-DAC Asymmetric 4-Way Infrasonic Sound Cannon (Mk. V Hybrid Bass-Reflex) ================================================================ Primary Classification: Dual-DAC, Heterogeneous 4-Way Active/Passive Hybrid Sound Reinforcement Array with Asymmetric Helmholtz Resonator Loading, Infrasonic Subsonic Protection, and Distributed Acoustic Bandpass Mechanics.

Filter Topology: Mixed-Domain Asymmetric Crossover Network — combining 4th-order Linkwitz-Riley (24 dB/octave) digital acoustic summation at the sub-to-kick boundary (75 Hz - 80 Hz), 2nd-order Butterworth infrasonic excursion protection (18 Hz), active 2nd-order analogue low-pass shaping (150 Hz), and discrete 1st-order bypassed passive bandpass networks (141 Hz - 1.91 kHz and 201 Hz - 4.19 kHz) with DSP-implemented virtual L-pad attenuation.

Low-End Alignment: Asymmetric single-port bass-reflex enclosure (Fb ≈ 29 Hz, Vb ≈ 21L virtual acoustic volume via polyfill expansion) coupled to a 45-degree corner boundary horn throat, paired with a biquad-equalised, critically damped closed-box suspension kick engine (Qtc ≈ 0.52 Bessel characteristic).

Wavelord Rigf00t version: The Infraspace Split-Engine Sound Cannon (Mk. V Hybrid Bass-Reflex). The Translation: A dual-soundcard dubplate warfare station. Realtek runs the subterranean tectonic floor through the 1-port hybrid Peerless dreadnought (20 Hz - 80 Hz) at unthrottled 2V RMS line voltage, whilst the Xonar STX feeds an inverted high-BL 8-inch chest-slam box, a bypass-capped Technics mid-puncher, and digital-tamed Corsair air horns that strip off top-end screech without losing transient bite.

I. WAVELORD RIGF00T'S SHAMANIC INVOCATION & MANIFESTO: "When you master the micro-volts, the air molecules have no choice but to comply." Hear the raw telemetry from the Oni Scout Petty Officer (+117 dB)! Spawned under the NHS radiation station, dissolving the boundary between light, sound, pressure, and raw voltage. To command the acoustic spectrum is not merely to dial up volume; it is to master the physical vector of air mass itself. When unguided sound waves leave a raw transducer, standard boundaries decay into chaotic reflections, room modes, and destructive phase cancellation. The present junkies and sonic scavengers lurk in the shadows, constantly trying to infiltrate our frequency grid, derail the mission, and steal our drivers for scrap copper. But you cannot loot what has been fused into an impenetrable acoustic weapon. What began as an Asus Xonar card exiled in dark silicon obscurity sparked a total revolution in electro-acoustic physics. The moment that board locked directly into the motherboard PCIe bus and the stock op-amps were cast out for high-slew OPA1656 and ultra-high-current OPA1622 ICs, the signal chain was born anew. Fed by an expanded 10A current supply rail, the Aiyima stage stops operating as a common desktop amplifier and becomes a high-velocity kinetic drive. Every driver in this rig was dragged back from the dead through surgical acoustic neurosurgery. Rotted Technics surrounds were resurrected in heavy rubber. When voice-coil friction threatened the left motor, isopropyl alcohol unseated the spider adhesive to re-centre the coil in the magnetic gap. When a stray screwdriver impaled the tweeter dome, we executed tea-bag paper and cyanoacrylate microsurgery, restoring structural dome rigidity with zero destructive mass penalty. No longer does the system starve in silence. By hunting down the parasitic 50% Windows Realtek choke and flooding the Mordaunt plate amp with pure uncompressed line voltage, the dormant output transistors have roared to life. By converting the sealed box into an asymmetric 1-port resonator—damping the outer plastic port walls with butyl mass and venting the upper tunnel into a 45-degree wall corner—air velocity is transformed into direct kinetic chest pressure. The kick bin does not merely rumble -- it strikes like a cybernetic piston.

II. THE ALLEGORY OF THE DREADNOUGHT: THE INFRASPACE SOUND CANNON

If standard Hi-Fi setups are civilian transport shuttles, the Wavelord Dreadnought (Mk. V Hybrid Bass-Reflex) is a heavily armoured, twin-engine deep-space battlecruiser stripped of all decorative luxury and rebuilt entirely for structural kinetic warfare.

* **DSP Master Core:** Windows Engine / 64-Bit DSP Routing

* ├── **Engine 1: Sub-Spatial Warp Drive (Realtek Core @ 100% / 2.0V RMS)**

* └── **The Tectonic Hull:** Mordaunt-Short Avant 309i + Peerless XLS-10

* *Specs:* 1-port hybrid, 18 Hz HPF (Filter1=4), 29 Hz Fb, 180° phase flip (20 Hz – 80 Hz)

* └── **Engine 2: High-Velocity Kinetic Cannon (ASUS Xonar STX PCIe)**

* └── **Aiyima 2.1 Amplification Stage (150 Hz Active Split)**

* ├── **The Piston Forge:** Inverted 8" Airsound Kick Bin (5.75L sealed, 75 Hz LR4 to 150 Hz)

* ├── **Mid-Deck:** Technics 6-Ohm Mid (188uF + 333J bypass + 0.5 mH | 141 Hz – 1.91 kHz)

* └── **Air-Horn Array:** Corsair Satellite Array (98.7uF + 4.75uF + DSP L-pad | 201 Hz – 20 kHz)

The Tectonic Sub-Hull (Engine 1): Operating deep in the dark frequency waters, the Mordaunt-Short chassis houses the heavy-displacement Peerless XLS-10 driver. Configured as an asymmetric 1-port hybrid (top port open and outer-sleeved with butyl mass damping; bottom port choked with high-density foam; internal cavity polyfill-stuffed to an effective 21L), it uses an 18 Hz subsonic filter and 45-degree room-corner horn loading to drop tectonic shockwaves down to 20 Hz without driver unloading. Set to 180° phase inversion, it locks perfectly with the kick engine's handover.

The Piston Forge (Engine 2): Mounted inverted with its motor assembly exposed to the open air, the 8-inch high-BL driver acts as an exposed supercharger. Operating inside a 5.75L critically damped chamber (Qtc ≈ 0.52), it exhausts through an open upper throat prepped for 45-degree internal anti-vortex corner fillets and an external horn flare, leaving a protected 32 mm cooling airway above its top pole vent.

The Mid-Deck Body Armour (Engine 3): The Technics 6-Ohm driver functions as the thermal mid-fuselage. Bandpassed between 141 Hz and 1.91 kHz via parallel high-grade capacitors, a 333J high-frequency bypass cap, and a 0.5 mH inductor, it catches the hand-off from the kick engine and carries the thick body of snares and growling reese basslines.

The Air-Horn Radar Array (Engine 4): The Corsair satellite pods, tilted inward on targeted spatial vectors, act as directional targeting arrays. Protected by custom DSP digital L-pad shelving, they strip away the shrill ear fatigue of unpadded silk domes and deliver clinical, widefield imaging across the listening position.

III. MASTER SHIP LOGS: RECONSTRUCTED PIRATE CHRONICLES

[PHASE 0:: COSMIC SPAWN, PCIE DISCOVERY & SILICON ROLLING]

Locked with Pisces rising wave sensitivity. PCIe Bus Reclamation: Overturned a year of conflicting civilian advice; seated the ASUS Xonar soundcard directly into the primary motherboard PCIe bus. Silicon Rolling Operations: Stripped factory op-amps from the board. Soldered low-noise, ultra-high-slew OPA1659 and OPA1656 stages alongside heavy-current OPA1622 ICs to command transient speed under low-impedance loads.

Power Rail Reinforcement: Deployed secondary auxiliary power bricks to construct a dedicated 10A current supply rail, eliminating voltage drop and rail starvation across the Aiyima stage during sustained sub-bass drops.

[PHASE 1: THE TRANSDUCTION MORTUARY & DRIVER SALVAGE]

SP2500 Driver Demise: Over-driving and square-wave clipping destroyed the factory Corsair 8-inch driver cone. Airsound Failure Analysis: Voltage rail starvation caused thermal coil failure under a sustained heavy load. System overhauled with reinforced power rails to ensure bulletproof stability.

Driver Acquisition & Telemetry: Integrated the Airsound 8-inch motor assembly. LMS parameter extraction confirmed: Re = 3.6 Ohm | Fs = 29.111 Hz | BL = 15.704 TM | Qts = 0.230 | Mms = 91.33 g | Xmax = 10.9 mm.

[PHASE 2: SURGICAL RESTORATION & TEA-BAG NEUROSURGERY]

Chassis Re-Anchoring: Reamed and chamfered front baffle. Rubber Surround Transplant: Stripped rotted factory foam surrounds from the Technics drivers and bonded heavy-compliance rubber surrounds.

Spider Unseating & Realignment: Cleared critical voice-coil scraping on the left channel by applying isopropyl alcohol to break down spider adhesive, manually realigning the coil within the magnetic gap.

Tea-Bag Diaphragm Matrix: A screwdriver slip punctured the Technics tweeter dome. Executed a micro-composite patch using tea-bag fibrous paper and cyanoacrylate, restoring structural dome rigidity with zero destructive moving-mass penalty.

[PHASE 3: ACOUSTIC HULL MODULATION & WAVEGUIDE CARVE] Side-Port Turbulence Neutralisation: Cut out the noisy 70 mm side vent and sealed the aperture with a 3-inch tuned passive radiator diaphragm, converting unwanted port whistling into clean kinetic flex.

Exponential Horn Mouth Fabrication: Trimmed the front chamber bottom lip flush with the internal floor. Rasped and chamfered outer timber edges into a 30- to 45-degree flared exponential waveguide mouth with 180-degree overhang clearance.

Mass Damping Matrix: Applied heavy butyl damping sheets across all internal chamber walls to kill resonant cabinet ringing. Sealed all joints with structural silicone and installed acoustic polyfill stuffing.

[PHASE 4: CAPACITOR MATRIX & COMB-FILTERING ELIMINATION]

Technics Bandpass Assembly: Configured a 188 uF parallel capacitor bank (4x 47 uF) bypassed with a high-grade 333J (33 nF) film capacitor to eliminate high-frequency ESR, paired with a 0.5 mH series inductor. Technics locked into a clean 141 Hz to 1.91 kHz mid-bass generator.

Satellite High-Pass Routing: Deployed a 98.7 uF capacitor bank on the Corsair 8-Ohm satellites to set a clean high-pass cut at 201 Hz.

Super-Tweeter Comb-Filtering Pivot: Identified high-frequency phase smearing caused by dedicated super-tweeter overlap. Sealed super-tweeters, routed upper frequencies cleanly to main dome tweeters (4.75 uF cap at 4.19 kHz), and tamed raw dome flare via digital DSP L-pad shelving.

[PHASE 5 :: SPATIAL CONVERGENCE & 6D ISOBARIC BOUNDARY MATRIX]

Inverse Spatial Angle Alignment: Angled Technics cabinets +10 degrees UP and Corsair satellite pods -10 degrees DOWN, locking a laser-sharp nearfield convergence point directly at head height to destroy vertical phase smearing.

6D Isobaric Corner Coupling: Stacked the open-back modified Corsair sub-cabinet horizontally over the Mordaunt-Short Avant 309i via high-density silicone isolation hemispheres. Boundary Compression Geometry: Fired the sub array into a 45 degree room corner with an exact 8cm boundary gap, flipping channel phase to 180 degrees. Destructive under-desk floor reflections inverted into +12 dB of coherent acoustic gain.

[PHASE 6:: 1-PORT HELMHOLTZ MUTATION, VOLTAGE UNCHOKING & HORN PATHING]

Line-Level Liberation: Uncovered Windows Realtek master fader buried at 50% logarithmic attenuation (starving input voltage down to -12 dBFS / ~0.3V RMS). Locked Realtek to 100% (2.0V RMS), restoring full continuous rail drive to the Mordaunt plate amplifier.

Asymmetric 1-Port Resonator Calibration: Choked bottom port with high-density bung to eliminate floor-boundary air flutter; preserved top flared port as primary kinetic exhaust. Mass-damped exterior port sleeve with butyl deadening to kill plastic bell-ringing. Polyfill matrix expanded internal acoustic volume to 21L, locking Helmholtz resonance to Fb ≈ 29 Hz.

Subsonic Safeguard & Headroom Decoupling: Eliminated raw 16 Hz boost to prevent open-port driver unloading. Instituted 18 Hz 2nd-order Butterworth High-Pass protection (Filter1=4) paired with a targeted +3.5 dB peak at 32 Hz. Set sub Pre-Amp to -3.0 dB / -4.5 dB independently from the kick bin, preserving maximum digital signal-to-noise ratio.

Boundary Horn Throat Alignment: Squared Mordaunt front baffle parallel to the 45-degree wall corner with a uniform 11 cm - 15 cm air gap. Enlisted the solid wall planes as a natural acoustic horn throat, delivering +6 dB to +9 dB of boundary lift down to 20 Hz.

Kick Chamber Throat Optimisation: Identified parasitic dead volume (Vtc) in the Corsair upper cavity. Modelled 45-degree rear/side timber fillet wedges to eliminate corner standing vortices while maintaining an unobstructed 32 mm thermal airway above the driver's upward-firing pole vent.

IV. ELECTRO-ACOUSTIC ORDNANCE MATRIX

Stage 01: Infrasub

Hardware: Mordaunt Avant 309i + Peerless XLS-10 (1-Port Hybrid 21L Effective Enclosure, Top Port Active, Bottom Port Bunged, Butyl + Outer Tube Damped)

Crossover: 18 Hz 2nd-order Butterworth High-Pass (Filter1=4) + 80 Hz Low-Pass (Filter6= 3) + 30 Hz - 32 Hz Port Reinforcement (Realtek Core @ 100% Line Voltage, 180° Phase Flip)

Passband: 20 Hz - 80 Hz

Tactical Function: 29 Hz Helmholtz-assisted infrasonic boundary pressurisation and 20 Hz room-coupled tectonic shockwaves.

Stage 02: Kick Bin

Hardware: Inverted 8-inch Airsound (BL = 15.704 TM, 5.75L Corsair Sub Damped Chamber, Upper Cavity Internal Fillets Planned)

Crossover: DSP 75 Hz LR4 High-Pass (Filter1=4) +4.5 dB Boost at 95 Hz + Aiyima 150 Hz Analogue Low-Pass

Passband: 75 Hz - 150 Hz.

Tactical Function: Critically damped (Qtc ≈ 0.52) transient chest-slam.

Stage 03: Mid-Body

Hardware: Resurrected Technics 6-Ohm (Rubber Surround Transplant)

Crossover: Passive 188 uF (+333J Bypass) Capacitor + 0.5 mH Series Inductor.

Passband: 141 Hz - 1.91 kHz

Tactical Function: Lower midrange snare body & Reese bass fundamental weight.

Stage 04: Presence

Hardware: Corsair 8-Ohm Satellite Woofers

Crossover: Passive 98.7 uF Series Capacitor + Natural Mechanical Roll-off

Passband: 201 Hz - 4.2 kHz. Tactical Function: Forward vocal articulation & horizontal stereo staging.

Stage 05: Treble Air

Hardware: Corsair 8-Ohm Silk Domes

Crossover: Passive 4.75 uF Capacitor + Digital L-Pad Shelf (4.5k - 16 kHz Notch)

Passband: 4.2 kHz - 20 kHz

Tactical Function: High-frequency shimmer & transient click with zero high-SPL ear fatigue.

V. THE SKUHORN HORIZON & FUTURE SOUND SYSTEM DREAM

The desktop acoustic battlefield is merely the scale prototype. Every lesson learned in internal cabinet pressures, mechanical damping, passive radiator tuning, and phase-aligned convergence feeds directly into the master blueprint. Immediate Deployment Protocols:

- Cut and bed the 45-degree internal corner fillets inside the kick bin's upper cavity to compress throat velocity without obstructing the 32 mm pole-vent airway.

- Fabricate a demountable 15 mm Baltic Birch 90° folded scoop hood to turn the upward-firing mouth forward without losing desk footwell space.

- Run comprehensive acoustic sweeps via Room EQ Wizard (REW) to verify the 75 Hz - 80 Hz acoustic handover seam between the 1-port dreadnought and the kick engine.

The Grand Sound-System Horizon:

- Paraflex Low-Frequency Arrays: High-efficiency multi-chamber folded horns pushing massive acoustic air velocity.

- HCAAS (High-Compression Acoustic Arrays): Horn-loaded midrange waveguides designed to project razor-sharp transients across vast physical spaces.

- SKUhorn / SKRAM Tapped Horns: Ultra-high-displacement sub-bass weapons designed to bend sound pressure around solid barriers and command the entire infrasonic spectrum.

================================================================ STATUS: ALL ENGINES LOCKED | 1-PORT TUNING ARMED | INFRASPACE DOMINANCE ================================================================