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Bag End InfraSub-18 Pro, PMM-8 Monitors Review


From longtime speaker manufacturer Bag End comes a new package designed for a variety of mixing, mastering and reference applications: the InfraSub-18 PRO and PMM-8 powered monitors. Designed to work as an integrated, self-powered turnkey system, this combination of workhorse speakers offers a host of useful features with loads of solid power and crisp detail.

All of Bag End’s monitors use Ed Long’s Time Align principles of design.

The InfraSub-18 PRO is the big brother to the original InfraSub-12, which I reviewed in Mix May 2004, and subsequently purchased. The InfraSub-18 PRO has all of the same basic features of the InfraSub-12; it’s a self-powered sub with an 18-inch cone loudspeaker in a sealed enclosure, using the same preamp and power amp as the InfraSub-12 PRO (500 watts), with an extended operating frequency down to 8 Hz. The amplifier also includes a built-in INFRA dual integrator providing a flat response down to 8 Hz, well below the audible range of human hearing. In many cases, one feels it as much as hears it. Like its smaller sib, the InfraSub-18 PRO is a seamless, smooth performer, with power to spare for the lowest part of the listening spectrum.

Included with the unit is the Status monitor, a handy visual cue device—connected via its own XLR cable to the back of the cabinet—to show “on” status, as well as dynamic filter threshold, should you push it hard enough. (Again, there’s power to spare; I rarely drove my test unit beyond the green “on” status indicator.)

Designed to work as the bedrock for a 2.1 or 5.1 system, the InfraSub-18 features a “passthrough” automatic crossover/LFE feed to connect from a console to the upper PMM8 speakers. Simply connect L and R, or LRC, Ls/Rs cables to the rear XLR male connectors, and then connect another set of XLRs out to the PMM8s (or other powered speakers of your choice).

Level for the InfraSub-18 is set via two rotary pots on the rear, and a variety of other useful functions (polarity, -10dB attenuation, etc.) are also provided.

The PMM-8s are the crown jewels of the system, featuring a single coaxial driver with separate 8-inch mid and 1.75-inch aluminum-compression HF drivers, passively crossing over at 2.9 kHz. This self-powered (rated at 150W nominal, 600W peak), time-aligned unit has XLR inputs (from the InfraSub-18 or directly from a console output with similar connectors) and a dedicated Neutrik Speakon AC power connector. (A very smart precaution; there’s never a possibility of plugging the wrong cable into the wrong socket!)

Additional features include front panel rocker switches for power, polarity reverse (brilliant idea!) and a 3-position EQ level switch for near-field/final (brightest, for listening to finished material from a distance), NFM™/Original (least-bright setting; no boost or attenuation of the material) and MFM™/Final and Distant/Original (medium brightness/middle setting). The subtle but important 1.5dB shift in HF levels hinge at 5 kHz make a clear difference, depending on your sitting position, work habits and overall speaker placement. There’s a tuned oval port on the bottom front of the cabinet, normally hidden by the detachable (and all but sonically transparent) black grille cloth. The PMM-8s roll off fairly quickly below 100 Hz, which mates very nicely with either the InfraSub-12 or -18.

All of Bag End’s monitors use Ed Long’s Time Align principles of design, which include physically lining up the drivers and adjusting driver and crossover delays. When a system is aligned, the fundamental and overtone timing is the same at the listening position as they are at the input of the monitor.

After a quick setup, the system came together flawlessly, with nothing more than minimal tweaking and physical adjustment for best listening angles and height. Starting with the default settings for the InfraSub-18 and the PMM-8s, I was up and running almost as quickly as I got them out of their boxes. The PMM-8s provided a rock-solid mono dead-center image right from the start, and stereo imaging was superb. At times, it felt like the normal L/R boundaries were pushed beyond the physical limits of the boxes themselves; a very nice experience. I haven’t listened to true Time-Aligned devices in quite a while (anyone remember the UREIs?), and my experience with the PMM-8s was quite startling—in a very good way. As some passages got louder, the soundstage seemed to expand right along with it.

Response time was impressively fast for percussive instruments, while string and wind instruments were creamy and smooth. Imaging for piano, guitar and even flute was stable and vivid. From solo jazz and classical vocalists to pipe organs to full orchestral mixes, the system never sagged or sounded clipped. With the extended range of the InfraSub-18 (and seemingly endless bass), I found nothing to complain about, except for perhaps a little exaggeration in the low mids on certain male voice-over recordings (which could have been the listening space itself). Most importantly, low-end response was smooth and effortless; never any hot spots or uneven results.

This past fall and winter season had me working on a wide range of projects, including live jazz mixes for NPR broadcasts, radio production voice-overs, full concert choir productions for DVD soundtracks, pipe organ recitals from the Kimmel Center in Philadelphia, and several CD remixing and mastering projects.

Having the luxury of a few months to really work with this system, there was time to compare production mixes with my other setups, including a pair of Lipinski L-505s (with its own InfraSub-12) and another listening-room system with Focal M8s and a consumer/generic sub. Many times, the PMM-8s surprised me with a little extra definition here, a little more detail on the reverbs there, and a wide, diffuse soundstage for live recording mixes. They more than held their own against my tried-and-true everyday-use power tools, proving to be a vital “second listen” for many critical mixes.

Mixing and mastering engineers require accurate, transportable mixes that don’t change depending on the format or delivery systems. Playback systems can’t lie, and they can’t crap out when pushed hard. For soundtracks, broadcasts, general mixing, final mastering and more, the InfraSub-18 and PMM-8s is one complete package that delivers clean, clear, non-fatiguing results.

I don’t work without a subwoofer. The point isn’t to rattle the walls, but just to know what’s going on down there. Far too many professional recordings still contain thumps and footfalls, buses going by and even the occasional subway rumble. Having spent a large part of this past decade successfully mixing with the InfraSub-12, I found that the InfraSub-18 (paired with the PMM-8s) delivers more of the same: reliable, accurate extended bass response matched with a superb pair of near-field speakers.

What was most impressive was how quickly this system sets up and sounds fantastic before any tweaking. If you’ve never worked with a true Time-Aligned™ system, this seamless pairing is worth a listen. The cost is comparable to most other similarly sized and powered systems, and if you’re considering investing a system upgrade, the extra features make the InfraSub-18 and PMM-8s a serious consideration.

Joe Hannigan is owner and chief engineer of Delaware-based Weston Sound.

Click on the Product Summary page to view the InfraSub-18 Pro product page.