Stereo Integrity HFS-24 – Dual 4 ohms 24″ Carbon Fiber Subwoofer

Stereo Integrity HFS 24″ Subwoofer

Our HFS-24 is the most cutting-edge compact 24″ subwoofer solution we have ever offered. The new shallow 24″ driver is equipped with a large 5″ diameter copper voice coil, single slug Neodynium cup XBL^2 motor, and the shallowest mounting depth of any large format subwoofer at only 8.75″ deep.

The single neo slug 5″ coil motor is mounted partially inside the basket, which is mostly responsible for the shallow mounting depth.

Two spider risers and a shallow Carbon Fiber/Rohacel/Kevlar sandwich cone body allow for 80 mm of peak mechanical travel. Attention to detail carries on to the flat stitched-on spider leads for maximum clearance. Every part of the HFS-24 was designed using FEA simulations, CAD software, and Klippel verification of the final subwoofer driver.

The HFS-24 was designed to be compact and light-weight while still allowing 2″ of total linear piston travel. Using computer simulations it can be quite difficult to get a 24″ cone to move more than 22-25 mm one direction (even with upwards of 3,000 watts of power).

Throughout years of listening and measuring our 24″ subwoofer platform subwoofers we understand that more than 2″ of cone travel is rarely approached so we decided to put all of our design prowess into the most compact 24″ subwoofer that we could produce.

To achieve one inch of linear positive and negative cone travel we immediately began designing an XBL^2 neo cup motor. XBL^2 offers industry leading Xmax-to-mounting depth ratios. The giant 5″ voice coil is towards the outside of the motor with the single slug of Neodynium accounting for part of the yoke and providing the necessary magnetic force for the subwoofer.

With an XBL^2 motor there are two rebates right in the middle of the voice coil so we placed one shorting ring in the outer rebate and another shorting ring in the form of a pole sleeve/cap to lower and linearize inductance for the lowest Re:Le subwoofer we have ever produced.

We carefully designed the HFS-24 to still offer class-leading low end performance even though we almost cut the mounting depth in half compared to our HS-24. Balancing motor strength, mass, and reducing inductance lower than ever, the HFS-24 provides tremendous performance levels in the widest options for enclosures for any 24″ subwoofer. It can be used in sealed, very small sealed, Dual-Opposed, Behind-The-Screen enclosures, and Infinite Baffle alignments.

Sealed enclosure sizes start at 3 ft^3 sealed.

Key Features:

• Single slug Neodynium dual gap XBL^2 Cup Motor
• 5″ diameter low inductance copper voice coil
• 10″ diameter Nomex spider for linear suspension travel
• Large pole vent
• Two internal shorting rings to control and linearize inductance
• Black anodized CNC aluminum motor coupling arms
• 25 mm one-way Xmax (50 mm total linear excursion) with 80 mm peak-to-peak stroke
• Compact 3 ft^3 sealed enclosure requirement
• Cast aluminum basket
• Carbon fiber and Kevlar sandwich cone body
• Large 4 AWG spring-loaded speaker terminals.

For optimal performance, we recommend a sealed enclosure size ranging from 4.5 ft^3 to 8 ft^3.

The HFS-24 requires a 22 3/8″ (22.375″) cutout, has a 24.35″ outer diameter, a mounting depth of 8.75″, and weighs 40 lbs. Experience the ultimate in bass reproduction with the HFS-24 subwoofer.

Specifications

Quick Info

• Weight 40 lbs
• Dimensions (OD) 24.35 inches
• Dimensions (Cutout) 22.375 inches
• Mounting Depth 8.75 inches
• Displacement 0.25 cubic feet
• RMS 3500 watts

Materials

• Surround Material Treated foam –
• Cone Material Carbon Fiber –
• Voice Coil Material Copper –

Thiele-Small Parameters

• Re 6.7 Ohms
• Fs 20.5 Hz
• Qes 0.68 –
• Qms 6.34 –
• Qts 0.61 –
• Le 2.1 mH
• Sd 322.8 square inches
• Vas 449.76 Liters
• BL 32.11 Tesla Meters
• Mms 807.29 grams
• Cms 70 µM/N
• Xmax 25 mm one-way 70% BL
• SPL 90.3 dB

Enclosure Recommendations

• Sealed Enclosure Volume 3-10 cubic feet
• Minimum Sealed Enclosure Volume 3 cubic feet
• Maximum Sealed Enclosure Volume 10 cubic feet

Additional Specifications

• Voice Coil Diameter 5 inches
• Terminal Type Large 4 AWG spring-loaded –
• Gross Weight 40 lbs