My Journey with Magnepan Room Correction and system optimization
System Optimization
Since the 1970s, when I first heard the Magnepan Tympani, I've been a fan of dipole speakers. I had many KEF and Focal speakers, and later I returned to dipole speakers: the Martin Logan Stylus, the Magnepan 1.7, and finally the Magnepan 3.7i. The best power amplifier for the Magnepan and all speakers is the Purifi power amplifier period. I wouldn't trade it for a $95,000 Pass Lab. Additionally I added a Rythmik F12 XLR3 subwoofer to satisfy my bass needs.
I started my journey of room correction with a Magnepan with a NAD C658 preamp and a full-featured Dirac room adjustment system. What happened:
Magnepan Room Correction Problems with Dirac
Using Dirac Live with Magnepan 3.7i speakers presented challenges. The time-alignment across the full frequency range made the Maggies sound boxy and unnatural. Dirac’s global phase correction interfered with the dipole radiation and the natural 'air' of the speakers. Even if I restricted the frequency range to 20 -200Hz, Dirac would time align my room reflections to 20khz. The result was technically correct but musically unsatisfying.
By the way the NAD C658 is a very good versatile piece of equipment, which is made for the Purifi power amp.
Advantages of Using the dbx VENU360 Instead of Dirac
Switching to the dbx VENU360 offered advantages over Dirac when paired with Magnepans. The dbx focuses on amplitude-based AutoEQ without imposing full-band time alignment. This preserves the natural openness and imaging of the Maggies while smoothing room-induced peaks and dips. Additionally, the dbx allows precise crossover and subwoofer integration (time alignment) without over-processing.
Going Analog into the dbx
Initially, the system was fed into the dbx via analog inputs (NAD’s XLR’s). This worked well, but it meant going through an extra A/D conversion before processing, which limited the potential clarity and added unnecessary conversion stages.
Switching to AES Digital Input with Wiim Pro Plus
The introduction of the Wiim Pro Plus streamer changed the chain significantly. Using the AES/EBU input on the dbx connecting the WiiM pro plus digital coax out over a 75-to-110 Ohm impedance converter, which allowed a direct digital handoff. This eliminated the redundant A/D step, ensuring cleaner signal delivery into the dbx.
Wiim Pro Plus – Best Software in Class (personal opinion)
Beyond the hardware, the Wiim Pro Plus stands out for its software ecosystem. The app is intuitive,
stable, and offers excess to all streaming apps. Compared to many competitors,
Restricting Output to 24/48 to Match the dbx
Although capable of 24/192 output, I restricted the Wiim to 24/48. This matches the dbx VENU360’s internal DSP rate, preventing unnecessary down sampling inside the processor. In this setup, the Wiim delivers a bit-perfect 24/48 stream directly clocked to the dbx, achieving maximum transparency.
Clocking and Jitter Considerations
With Sample Rate Conversion disabled on the dbx, the processor locks directly to the Wiim’s low-jitter clock. This ensures stable, accurate timing. Feeding 24/192 into the dbx would have forced a resample down to 48 kHz internally and use the lower quality DBX clock. By restricting the Wiim to 24/48, the system avoids this redundancy.
High Headroom for Volume Control
The Wiim Pro Plus upsamples internally to 32-bit precision for volume control. Feeding the dbx a 24-bit, 48 kHz stream ensures over 140 dB of dynamic range, so the Wiim volume control provides plenty of headroom without audible resolution loss. This makes digital volume control transparent and safe, even at moderate listening levels.
Final Take
I calibrated the system with the dbx venue 360 connected to the dbx RTA microphone. I used the DBX AutoEQ. The calculated DBX room correction can then be fine-tuned manually. I used the microphone positions for the right and left ear. This results in a very close seating position, but with the best results for me. Finally, a few thoughts on high-resolution DACs or improving with better streamer transport, etc. With room noise of ~30dB and the influence of the room and speakers, investing in expensive equipment is not worth it. I checked out expensive DACs, but in the end, I sold them; I didn't hear any noticeable difference.
With the WiiM pro plus -> DBX Venue 360 -> Purifi -> 3.7i + Rythmik system, I'm happy with my Maggies. Finally.
