Last January, I was invited to participate in beta trials for the flagship sub in a new line of Polk subwoofers, the DSW MicroPro series. If you have been reading me for a while, you know that I am a true SVS cultist, but I'm not opposed to having a little fling every now and then with other subs. You might also be shocked to learn that, from time to time, I push my revered modified SDA SRS 1.2TL's to the side and audition other loudspeakers [footnote 1].;)
I figured the MicroPro and I would have a few laughs and then I'd send it back. Sometimes flings turn into longtime relationships.:)
Some changes were made to the MP4K's digital amplifier and software based on beta tester's feedback and then the improved amplifiers were sent to the testers. Polk's engineering department confirmed that the beta versions, after the initial amplifier improvements, are essentially the same as production versions.
Figures 1 and 2 show how much fun the UPS handlers had with my DSW MicroPro 4000, which shall hereafter be referred to as the MP4K [footnote 2].
Figure 1. The good folks at UPS handled my MP4K with their
usual kind attentions. Thanks UPS.
Figure 2. The box and styrofoam padding were busted to Hell, but the
MP4K miraculously made it to me unscathed. Incredible!
MSRP: $1770, 1200 watts continuous digital power amplifier, 16-3/4"H x 15-1/2"W x 16-1/2"D, weight: 57.5 pounds, 3 dB limits: 24 Hz and 90 Hz, 12" driver with 12" square passive radiator.
Under household lighting, I could detect no defects in the finish. It appeared to be perfectly flat with no discontinuities whatsoever. I wheeled it out to my front sidewalk and took another look in bright sunlight. I couldn't find any defects then either.
I liked the grille-less face. It made the MP4K more sculptural in appearance. It was a perfect aesthetic match with my Samsung plasma, which also has a gloss black finish and a blue LED on the front.
Figure3. No runs, drips, swirls, bubbles, scratches, cracks or dimples.
No imperfections at all in the mirror gloss piano black finish.
Figure 4. Square and black and shiney. You could use the sides and top
of the MP4K as a shaving mirror.
Figure 5. With the exception of the microphone input, the MP4K has
the usual complement of inputs/outputs. I appreciated the detachable
power cord capability.
Figure 6. The MP4K blended in seamlessly with my Magnepan MG 12's.
Figure 7. All the cool blue lights.
Setup and Accessories
The MP4K comes with a remote control, microphone and detachable power cord. Figure 8 shows the stock MP4K 18 AWG power cord (good), a Volex 14 AWG power cord (better), and a MagicPower 10 AWG power cord (best). The Volex cord provided a subtle improvement in bass definition over the stock cord. The MagicPower cord provided noticeably more bass definition and weight. However, in order to use the MagicPower cord, the end connectors would have to be changed to 90 degree angled connectors. Otherwise, the power cord ends would cause the sub to sit out too far from the wall. Until I modify the MagicPower cord, the Volex cord will be used. I had to similarly modify the MagicPower cord used with my SVS PB12 Ultra/2 subwoofer. Of course, for beta testing feedback purposes, the stock cord was used.
Figure 8. The stock MP4K power cord (front center), Signal Cable
MagicPower cord, and Volex power cord.
Figure 9. MP4K AutoPRO microphone.
The user has the option of manual setup or using the AutoPRO (Automatic Polk Room Optimizer) feature which uses a microphone to take sound samples of the listening room and then adjust the amplifier for smoothest response. When using AutoPRO, I clipped the microphone to a camera tripod at ear height at the listening position and let it do its thing. The sub sequenced through a set of test tones for about 90 seconds to two minutes, depending on the location in the room. Some of the test tones exceeded 100 dB-C, so some users might want to wear ear protection or leave the room while the AutoPRO routine completes.
While I liked the concept of the auto room correction feature, I was not entirely happy with the sound that resulted from it. The frequency response curve after room correction was smoother, but the sound from the sub was less natural sounding and had less definition and articulation. It wasn’t "muddy", but it did sound a bit veiled, as if a sheet had been placed over the sub. Also, after auto correction, the sub did not blend in with the main speakers as well as it did with the manual setting.
Setting the volume and using one of the manual PRO presets gave me the best sound with fast, tight, natural sounding bass. I realize that auto correction was probably not designed with the tastes and sensibilities of the audio purist in mind. Auto room correction will probably satisfy the vast majority of MP4K users.
The blue LED on the front does more than just indicate that the sub is turned on. It also confirms, through a number of blinks, volume and other settings sent from the remote. For example, volume level 24 would be indicated by two long blinks and four rapid blinks. The blinking LED is much easier to read from across the room than an alpha-numeric display would be. Most subs make you do a reach around to the rear to access the controls.
Figure 10. The MP4K remote is the same size as a standard credit
Listening Evaluations - Master Bedroom A/V System
Subwoofer performance will vary depending on the type of floor the unit is sitting on. All the floors in my home are either 3/4" thick hardwood glued to slab or ceramic tile glued to slab.
The MP4K was first evaluated in my master bedroom system, where it replaced an SVS SB 12 Plus subwoofer (MSRP $749 in rosenut veneer finish) and was paired with a set of Magnepan MG12 speakers. During listening evaluations, the preamp/processor volume control was adjusted to maintain an average sound level of 85 dB-C.
After manual set up, the MP4K totally disappeared and huge bass sounds seemed to come from the area between the planar magnetic panels. The bass was fast and articulate and presented a degree of impact and realism that was unattainable with the SVS SB12 Plus.
Figure 11. Two compact bass radiators prepare to square off.
Immediately after the MBR system trials were over, the SVS was retired to the confines of my audio closet and a decision was made to purchase an MP4K when they came on the market. Fortunately, for my wallet, Polk, Inc. offered the beta testers the opportunity to keep the production samples in appreciation for our assistance. Such good audio largess.:)
[Footnote 1] Once, I even replaced a set of SDA's with another loudspeaker type and brand. Don't believe me? See it for yourself here.
[Footnote 2] Polk, Inc. prefers the acronym "uPro4k".