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SKU: SI-HFS24-D4-STD
Stereo Integrity
HFS-24
Compact 24 Inch Subwoofer | Sold Individually
The HFS-24 is the compact member of the Stereo Integrity 24 inch family. It mounts in 8.75 inches, 4 inches shallower than the HS-24, and the driver weighs 40 pounds. Stereo Integrity got there by setting a single slug neodymium cup motor partly inside the basket and driving a large 5 inch copper voice coil. Like its other 24 inch drivers, every part was designed with FEA simulation and CAD, and the finished driver was verified on a Klippel system.
The reasoning is practical. After years of listening to and measuring its 24 inch platform, Stereo Integrity found that more than 2 inches of total cone travel is rarely used. So the HFS-24 is built around 25 mm of one-way linear excursion and 80 mm of peak-to-peak mechanical travel, with the savings going into depth and weight.
A single slug of neodymium forms part of the yoke in a dual gap XBL^2 cup motor, a topology chosen for its high ratio of excursion to mounting depth. A large pole vent keeps the motor breathing.
One shorting ring sits in the outer rebate and a second takes the form of a pole sleeve and cap. Together they lower and linearize inductance, and Stereo Integrity says this is its lowest Re to Le subwoofer to date.
The low inductance 5 inch copper coil sits toward the outside of the motor, supported by a 10 inch Nomex spider on two spider risers with flat, stitched-on leads for clearance.
A shallow carbon fiber, Rohacell, and Kevlar sandwich cone keeps the moving assembly stiff. It rides in a cast aluminum basket with black anodized CNC aluminum coupling arms and large 4 AWG spring-loaded terminals.
Stereo Integrity rates the HFS-24 at 3500 watts RMS and designed it for a wide range of enclosures: sealed, very small sealed, dual-opposed, behind-the-screen, and infinite baffle. Sealed enclosures start at 3 cubic feet, the specification sheet lists a sealed range of 3 to 10 cubic feet, and Stereo Integrity recommends 4.5 to 8 cubic feet for best performance.
Surround options: The standard version uses a treated foam surround and lists an Fs of 20.5 Hz with a Qts of 0.61. The accordion version uses a cloth surround and lists 23.2 Hz with a Qts of 0.48.
The HFS-24 is offered in dual 4 ohm only. The two coils wire to 2 ohms in parallel or 8 ohms in series.
Cutout: 22.375 in. Outer diameter: 24.35 in. Mounting depth: 8.75 in. Displacement: 0.25 cu ft. Driver weight: 40 lb.
The HFS-24 is built to order and ships by freight. Call 931-563-5151 before you order for current lead time and delivery options.
Audio Intensity is an authorized Stereo Integrity dealer, and we build enclosures around their drivers.
Call 931-563-5151 to plan an HFS-24 build, from enclosure style to amplifier power.
| Specifications | ||
|---|---|---|
| Model | HFS-24 | |
| Size | 24 in | |
| Voice Coil Configuration | Dual 4 ohm | |
| Power Handling (RMS) | 3500 W | |
| Voice Coil | 5 in low inductance copper | |
| Motor | Single slug neodymium dual gap XBL^2 cup, two shorting rings | |
| Spider | 10 in Nomex on two spider risers | |
| Cone | Carbon fiber, Rohacell and Kevlar sandwich | |
| Frame | Cast aluminum with CNC aluminum coupling arms | |
| Terminals | Large 4 AWG spring-loaded | |
| Outer Diameter | 24.35 in | |
| Cutout | 22.375 in | |
| Mounting Depth | 8.75 in | |
| Driver Displacement | 0.25 cu ft | |
| Peak-to-Peak Mechanical Travel | 80 mm | |
| Weight | 40 lb driver, 45 lb listed shipping weight | |
| Thiele-Small Parameters | ||
| Parameter | Standard Surround | Accordion Surround |
| Surround Material | Treated foam | Cloth |
| Resonant Frequency (Fs) | 20.5 Hz | 23.2 Hz |
| DC Resistance (Re) | 6.7 ohm | 6.1 ohm |
| Voice Coil Inductance (Le) | 2.1 mH | 2.1 mH |
| Electrical Q (Qes) | 0.68 | 0.52 |
| Mechanical Q (Qms) | 6.34 | 7.45 |
| Total Q (Qts) | 0.61 | 0.48 |
| Equivalent Compliance (Vas) | 449.76 L | 449.76 L |
| Effective Piston Area (Sd) | 322.8 sq in | 314.1 sq in |
| Force Factor (Bl) | 32.11 Tm | 33.5 Tm |
| Moving Mass (Mms) | 807.29 g | 608.7 g |
| Suspension Compliance (Cms) | 70 um/N | 77 um/N |
| Linear Excursion (Xmax) | 25 mm one-way (70% Bl) | 25 mm one-way (70% Bl) |
| SPL | 90.3 dB | 92.9 dB |
| Enclosure and Response | ||
| Sealed Range | 3 to 10 cu ft | |
| Recommended Sealed | 4.5 to 8 cu ft | |
| Other Alignments | Very small sealed, dual-opposed, behind-the-screen, infinite baffle | |
| Frequency Response | 3 Hz to 2000 Hz | |
| Figures as published by Stereo Integrity. The two parameter sets correspond to the standard and accordion surround options. | ||
See every Stereo Integrity subwoofer box and enclosure, each cut for a specific Stereo Integrity driver.
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