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Stereo Integrity
Stereo Integrity HFS-24 | Compact 24 Inch Subwoofer
SKU: SI-HFS24-D4-STD
$ 1,999.00
QUICK SPECS
- Type: Compact 24 in subwoofer, sold individually
- Mounting Depth: 8.75 in, 22.375 in cutout
- Power Handling: 3500W RMS, dual 4 ohm
- Excursion: 25 mm one-way linear
- Enclosure: 4.5 to 8 cu ft sealed recommended
Stereo Integrity HFS-24 | Compact 24 Inch Subwoofer
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Stereo Integrity
HFS-24
Compact 24 Inch Subwoofer | Sold Individually
8.75 in Mounting Depth 5 in Copper Voice Coil 3500W RMS 25 mm One-Way Xmax Dual 4 Ohm
A 24 Inch Subwoofer in 8.75 Inches
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.
Engineering Highlights
Neodymium XBL^2 Cup Motor
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.
Two Shorting Rings
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.
5 Inch Copper Voice Coil
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.
Carbon Fiber Sandwich Cone
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.
Enclosure Flexibility
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.
Wiring
The HFS-24 is offered in dual 4 ohm only. The two coils wire to 2 ohms in parallel or 8 ohms in series.
Fitment and Ordering
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.
Authorized Stereo Integrity Dealer
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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