Hertz HMX 7 7 S LD SW 2
Best box: 10.0 L bass reflex tuned to 51.0 Hz · F3 73.2 Hz
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Comparable 7.5" Drivers
Drivers with similar piston area, resonance and Qts — useful alternatives when the Hertz HMX 7 7 S LD SW 2 does not fit your target box volume or tuning. Each entry links to its full enclosure design and Thiele/Small parameters.
Recommended Bass Reflex (Vented)
PORT BUILDABLE| Net Box Volume (Vb) | 10.0 Liters |
| Tuning Frequency (Fb) | 51.0 Hz |
| F3 (-3 dB Cutoff) | 73.2 Hz |
| F6 / F10 Extension | 60.6 Hz / 46.5 Hz |
| Port Inner Diameter | Ø 5.0 cm |
| Port Physical Length | 19.1 cm |
| First Pipe Resonance | 903.0 Hz |
| Estimated MOL @ F3 | 111.6 dB SPL |
Sealed (Acoustic Suspension) — compromise
SUITS INFINITE / OPEN BAFFLEWith Qts 0.72 a Butterworth (Qtc 0.707) box would be many times Vas. A box equal to Vas reaches Qtc 1.018; for a flat response this driver is better used on an infinite (IB) or open baffle.
| Net Box Volume (Vb) | 12.5 Liters |
| System Q (Qtc) | 1.018 (above Butterworth: Qtc cannot fall below Qts (0.72)) |
| System Resonance (Fc) | 84.9 Hz |
| F3 (-3 dB Cutoff) | 71.2 Hz |
| F6 / F10 Extension | 58.6 Hz / 46.9 Hz |
| Air Spring Linearity | High (Zero port compression) |
Thiele/Small Parameters
| Resonance (Fs) | 60.0 Hz |
| Total Q (Qts) | 0.72 |
| Electrical Q (Qes) | 0.767 |
| Mechanical Q (Qms) | 11.8 |
| Equivalent Volume (Vas) | 12.5 Liters |
| Diaphragm Area (Sd) | 167.3 cm² |
| DC Resistance (Re) | 3.3 Ω |
| Efficiency Bandwidth Product (EBP) | 78.2 |
| Linear Excursion (Xmax) | 6.0 mm |
| Thermal Power (Pe) | N/A W |
| Nominal Diameter | 7.5" |
| Catalog Source | Load Forge catalog (manufacturer datasheets and retailer listings) |
Frequently Asked Questions
What is the recommended ported (bass reflex) box volume for Hertz HMX 7 7 S LD SW 2?
Load Forge's calculated alignment puts Hertz HMX 7 7 S LD SW 2 in a 10.0 liter vented enclosure tuned to 51.0 Hz, reaching an F3 cutoff of approximately 73.2 Hz.
Can Hertz HMX 7 7 S LD SW 2 be used in a sealed box?
Yes. In a sealed (acoustic suspension) enclosure of 12.5 liters with a Qtc of 1.018 (above Butterworth: Qtc cannot fall below Qts (0.72)), the system exhibits an F3 of 71.2 Hz.
What port dimensions should be used for Hertz HMX 7 7 S LD SW 2 to avoid port chuffing?
Sized from cone displacement (Sd × Xmax), a minimum port diameter of 5.0 cm with a length of 19.1 cm is suggested; check the port air velocity at your drive level in the Load Forge Studio.
Shareable Acoustic Card for Forums & Social Media
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