I think Amir's conclusions in his test of the LRS is quite fitting...
"The Magnepan LRS is a hugely flawed speaker with moments of delight."
"The best way I can explain this is that the designers solved 30% of the physics of building a speaker, and threw you in there to solve the rest! You take on the job of spending what must be a lifetime messing with location, tilt, EQ, etc. to get sound that is good for more than a few select tracks."
I think this is true of virtually any speaker made by Magnepan. I've not heard the 30.7, but all other current Magnepans, and quite a few of the previous generations. At some point I owned seven pairs of them. Currently I have a pair of 1.5, 1.6 and 3.7, and two pairs 3.6. I have ripped them all apart, measured them and know them in and out.
Some observations:
- None of them come close to a smooth and controlled in-room frequency response, regardless of room and setup. 20.7 is the best I've measured among them. LRS+ the worst.
- Very uneven off-axis response
- Bass distortion is horrible at any SPL
- The bass panel's distortion increase at lot below 400 Hz, but is extremely low above 400 Hz.
- The mid/tweeter panel's distortion increase a lot below 700 Hz, but is extremely low above 700 Hz.
- Both panels show virtually no resonant behavior/breakup at all.
- The true ribbon tweeter of 3.6/3.7 will buzz and distort below 2500 Hz
- The wire (1.5/3.6) mid/tweeter panel's sensitivity is about 80 dB @ 2.83V
- The QR (1.6/3.7) mid/tweeter panel's sensitivity is about 78 dB @ 2.83V
- The ribbon tweeter's sensitivity is about 80 dB @ 2.83V
- The bass panel's sensitivity is quite good at 90 dB @ 2.83V above 500 Hz. But expect 10 dB loss at lower frequencies.
If you want to get the best out of your Magnepans, I suggest the following based on my own experience:
- Remove the passive crossovers and replace them with DSP and multiple amps.
- Bypass the fuses as well, and consider removing the original connectors and solder new wire directly to the panels. The original wiring use spade connectors, and have a tendency to corrode.
- Use high quality, high power amps, as they will need a lot of watts. The impedance is ruler flat, so they are very easy to drive.
- Use very steep FIR filters, because the acoustic distance between the different drivers is large. Steep filters (i.e. Brickwall filters) help reduce off-axis comb filtering at the crossover points to a minimum.
- Cross over the bass panel to a dedicated dipole woofer system no lower than 400 Hz.
- Use the good sensitivity of the bass panel to cover most of the midrange. Crossing over at 3 kHz is indeed possible without scarifying off-axis response.
- Do not cross over the true ribbon tweeter (3.6/3.7) lower than 4 kHz. I currently cross at 6 kHz.
- Consider removing the front grilles of the 3.6/3.7. They cause reflections and diffraction for the mid/hi panel and ribbon tweeter.
