GRS 3AS-4
Best box: 1.5 L bass reflex tuned to 105.4 Hz · F3 120.1 Hz
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Comparable 3.0" Drivers
Drivers with similar piston area, resonance and Qts — useful alternatives when the GRS 3AS-4 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) | 1.5 Liters |
| Tuning Frequency (Fb) | 105.4 Hz |
| F3 (-3 dB Cutoff) | 120.1 Hz |
| F6 / F10 Extension | 96.1 Hz / 79.1 Hz |
| Port Inner Diameter | Ø 5.0 cm |
| Port Physical Length | 31.7 cm |
| First Pipe Resonance | 542.0 Hz |
| Estimated MOL @ F3 | 97.0 dB SPL |
Sealed (Acoustic Suspension) — compromise
SUITS INFINITE / OPEN BAFFLEWith Qts 0.95 a Butterworth (Qtc 0.707) box would be many times Vas. A box equal to Vas reaches Qtc 1.344; for a flat response this driver is better used on an infinite (IB) or open baffle.
| Net Box Volume (Vb) | 0.9 Liters |
| System Q (Qtc) | 1.344 (above Butterworth: Qtc cannot fall below Qts (0.95)) |
| System Resonance (Fc) | 175.4 Hz |
| F3 (-3 dB Cutoff) | 141.9 Hz |
| F6 / F10 Extension | 120.5 Hz / 98.9 Hz |
| Air Spring Linearity | High (Zero port compression) |
Thiele/Small Parameters
| Resonance (Fs) | 124.0 Hz |
| Total Q (Qts) | 0.95 |
| Electrical Q (Qes) | 1.298 |
| Mechanical Q (Qms) | 3.54 |
| Equivalent Volume (Vas) | 0.9 Liters |
| Diaphragm Area (Sd) | 36.1 cm² |
| DC Resistance (Re) | 3.6 Ω |
| Efficiency Bandwidth Product (EBP) | 95.5 |
| Linear Excursion (Xmax) | 5.0 mm |
| Thermal Power (Pe) | 15.0 W |
| Nominal Diameter | 3.0" |
| Catalog Source | Load Forge catalog (manufacturer datasheets and retailer listings) |
Frequently Asked Questions
What is the recommended ported (bass reflex) box volume for GRS 3AS-4?
Load Forge's calculated alignment puts GRS 3AS-4 in a 1.5 liter vented enclosure tuned to 105.4 Hz, reaching an F3 cutoff of approximately 120.1 Hz.
Can GRS 3AS-4 be used in a sealed box?
Yes. In a sealed (acoustic suspension) enclosure of 0.9 liters with a Qtc of 1.344 (above Butterworth: Qtc cannot fall below Qts (0.95)), the system exhibits an F3 of 141.9 Hz.
What port dimensions should be used for GRS 3AS-4 to avoid port chuffing?
Sized from cone displacement (Sd × Xmax), a minimum port diameter of 5.0 cm with a length of 31.7 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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