Acr Speaker 1240-mk2-pa-classic
Best box: 121.9 L bass reflex tuned to 44.1 Hz · F3 41.9 Hz
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Comparable 12.0" Drivers
Drivers with similar piston area, resonance and Qts — useful alternatives when the Acr Speaker 1240-mk2-pa-classic does not fit your target box volume or tuning. Each entry links to its full enclosure design and Thiele/Small parameters.
⚠️ Engineering Notice for Builders
- Large enclosure volume (121.9 L) requires extensive internal matrix bracing to prevent panel resonance.
Recommended Bass Reflex (Vented)
PORT BUILDABLE| Net Box Volume (Vb) | 121.9 Liters |
| Tuning Frequency (Fb) | 44.1 Hz |
| F3 (-3 dB Cutoff) | 41.9 Hz |
| F6 / F10 Extension | 37.5 Hz / 33.2 Hz |
| Port Inner Diameter | Ø 10.0 cm |
| Port Physical Length | 2.8 cm |
| First Pipe Resonance | 6186.0 Hz |
| Estimated MOL @ F3 | 120.6 dB SPL |
Recommended Sealed (Acoustic Suspension)
MAX TRANSIENT DAMPING| Net Box Volume (Vb) | 53.0 Liters |
| System Q (Qtc) | 0.707 (Butterworth) |
| System Resonance (Fc) | 75.7 Hz |
| F3 (-3 dB Cutoff) | 77.2 Hz |
| F6 / F10 Extension | 58.4 Hz / 44.2 Hz |
| Air Spring Linearity | High (Zero port compression) |
Thiele/Small Parameters
| Resonance (Fs) | 45.0 Hz |
| Total Q (Qts) | 0.39 |
| Electrical Q (Qes) | 0.42 |
| Mechanical Q (Qms) | 5.42 |
| Equivalent Volume (Vas) | 121.2 Liters |
| Diaphragm Area (Sd) | 498.8 cm² |
| DC Resistance (Re) | 5.6 Ω |
| Efficiency Bandwidth Product (EBP) | 107.1 |
| Linear Excursion (Xmax) | 5.8 mm |
| Thermal Power (Pe) | N/A W |
| Nominal Diameter | 12.0" |
| Catalog Source | Load Forge catalog (manufacturer datasheets and retailer listings) |
Frequently Asked Questions
What is the recommended ported (bass reflex) box volume for Acr Speaker 1240-mk2-pa-classic?
Load Forge's calculated alignment puts Acr Speaker 1240-mk2-pa-classic in a 121.9 liter vented enclosure tuned to 44.1 Hz, reaching an F3 cutoff of approximately 41.9 Hz.
Can Acr Speaker 1240-mk2-pa-classic be used in a sealed box?
Yes. In a sealed (acoustic suspension) enclosure of 53.0 liters with a Qtc of 0.707 (Butterworth), the system exhibits an F3 of 77.2 Hz.
What port dimensions should be used for Acr Speaker 1240-mk2-pa-classic to avoid port chuffing?
Sized from cone displacement (Sd × Xmax), a minimum port diameter of 10.0 cm with a length of 2.8 cm is suggested; check the port air velocity at your drive level in the Load Forge Studio.
Shareable Acoustic Card for Forums & Social Media
Embed this design card on DIYAudio, AVSForum, Reddit, or Facebook. It shows the calculated F3, MOL (when the power rating is published) and box parameters.
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