Acr Speaker 1238-mk1-pc-acr-classic-new
Best box: 300.6 L bass reflex tuned to 21.9 Hz · F3 37.2 Hz
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Comparable 12.0" Drivers
Drivers with similar piston area, resonance and Qts — useful alternatives when the Acr Speaker 1238-mk1-pc-acr-classic-new 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
- The textbook alignment (100.2 L at 36.5 Hz) would need a 3.3 cm port; the recommendation is retuned to 300.6 L at 21.9 Hz so the port can be built.
- Large enclosure volume (300.6 L) requires extensive internal matrix bracing to prevent panel resonance.
- Limited linear excursion (Xmax: 3.93 mm); set a high-pass subsonic filter at 25–30 Hz when driven with high power.
Recommended Bass Reflex (Vented)
PORT BUILDABLE| Net Box Volume (Vb) | 300.6 Liters |
| Tuning Frequency (Fb) | 21.9 Hz |
| F3 (-3 dB Cutoff) | 37.2 Hz |
| F6 / F10 Extension | 28.8 Hz / 17.3 Hz |
| Port Inner Diameter | Ø 6.8 cm |
| Port Physical Length | 2.7 cm |
| First Pipe Resonance | 6397.0 Hz |
| Estimated MOL @ F3 | 103.9 dB SPL |
Sealed (Acoustic Suspension) — compromise
SUITS INFINITE / OPEN BAFFLEWith Qts 0.92 a Butterworth (Qtc 0.707) box would be many times Vas. A box equal to Vas reaches Qtc 1.301; for a flat response this driver is better used on an infinite (IB) or open baffle.
| Net Box Volume (Vb) | 125.3 Liters |
| System Q (Qtc) | 1.301 (above Butterworth: Qtc cannot fall below Qts (0.92)) |
| System Resonance (Fc) | 60.8 Hz |
| F3 (-3 dB Cutoff) | 47.5 Hz |
| F6 / F10 Extension | 40.4 Hz / 33.2 Hz |
| Air Spring Linearity | High (Zero port compression) |
Thiele/Small Parameters
| Resonance (Fs) | 43.0 Hz |
| Total Q (Qts) | 0.92 |
| Electrical Q (Qes) | 1.064 |
| Mechanical Q (Qms) | 6.79 |
| Equivalent Volume (Vas) | 125.3 Liters |
| Diaphragm Area (Sd) | 506.7 cm² |
| DC Resistance (Re) | 5.6 Ω |
| Efficiency Bandwidth Product (EBP) | 40.4 |
| Linear Excursion (Xmax) | 3.9 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 1238-mk1-pc-acr-classic-new?
Load Forge's calculated alignment puts Acr Speaker 1238-mk1-pc-acr-classic-new in a 300.6 liter vented enclosure tuned to 21.9 Hz, reaching an F3 cutoff of approximately 37.2 Hz.
Can Acr Speaker 1238-mk1-pc-acr-classic-new be used in a sealed box?
Yes. In a sealed (acoustic suspension) enclosure of 125.3 liters with a Qtc of 1.301 (above Butterworth: Qtc cannot fall below Qts (0.92)), the system exhibits an F3 of 47.5 Hz.
What port dimensions should be used for Acr Speaker 1238-mk1-pc-acr-classic-new to avoid port chuffing?
Sized from cone displacement (Sd × Xmax), a minimum port diameter of 6.8 cm with a length of 2.7 cm is suggested; check the port air velocity at your drive level in the Load Forge Studio.
Shareable Acoustic Card for Forums & Social Media
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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