Bag End is a speaker manufacturer that has always been renowned for its insane low end. For many years, the company has offered subwoofers that are flat
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Bag End is a speaker manufacturer that has always been renowned for its insane low end. For many years, the company has offered subwoofers that are flat down to 8 Hz — that's nearly all the way down to the “brown” frequencies. The fact is, Bag End also offers high-quality full-bandwidth systems. I test-drove a pair of Bag End M6 studio monitors paired with an Infrasub-12 Pro subwoofer. This is truly an excellent system that should be considered if you need solid, accurate monitoring in your studio, particularly if you engage in the kind of mixing that requires excellent resolution in the low end.


The M6 monitor is a two-way system with a 6-inch low-frequency driver and a coaxially mounted high-frequency driver. The low-frequency driver is made out of polypropylene and is capable of a pretty significant throw. Behind the low-frequency driver's dome is a 1-inch neodymium high-frequency driver. The enclosure is made of ¾-inch MDF 9 (medium density fiberboard) and is thus very solid. It measures 14 inches high by 9 inches wide by 9 inches deep. The box weighs 15 pounds and features a nice black textured-paint finish. The total volume of the enclosure is 0.4 cubic feet, enabling solid bass response. This is not a ported monitor, so there is none of the tubby resonance that so many monitors of this size exhibit. The M6s ship with a black nylon grille cloth on a wood frame that pops right off if you wish to remove it. Optional wall-mount brackets are also available, and the connection to your amplifier is made with five-way binding posts.

The total impedance of the system is 8 ohms, and the published frequency response is 60 Hz to 20 kHz. The crossover happens at 3.5 kHz and is accomplished with Bag End's proprietary Passive Time-Align equalizer filter (more on this to come). The rated sensitivity is 87 dB SPL, and distortion is rated at less than 3 percent THD. These monitors can handle 90W of continuous power and 360W of instantaneous peaks. Obviously, these are passive monitors that require a separate amplifier.

The idea behind aligning the drivers of a multi-band loudspeaker is not new. In the live-sound world, front-of-house engineers spend hours prior to the concert aligning the lows, the low mids, the high mids and the highs so that the entire frequency range of the program material arrives at the ears of the audience in simultaneous coherency. There are any number of schemes to accomplish this, ranging from physically placing the drivers so that the various slices of bandwidth arrive coherently to more sophisticated electronic delays. Bag End's Time-Align system is even more sophisticated and results in transients being presented simultaneously by both drivers. In turn, the smear or blurring associated with misaligned drivers is eliminated, and the resultant reproduction exhibits much more clarity.


The Infrasub-12 Pro subwoofer is a self-powered sub based on a 12-inch front-firing driver with a truly substantial foam suspension ring, enabling a significantly long throw. Its solid enclosure is made of ¾-inch MDF and measures 15.5 inches high by 18 inches wide by 16 inches deep. The enclosure is magnetically shielded due to the driver's particularly massive magnet, and it has a removable black nylon grille cloth mounted on a wood frame. It weighs 56 pounds, largely due to the speaker's magnet and the internal amplifier. The amp produces a healthy 400W and marries nicely with the low-frequency driver. One particularly nice feature of this subwoofer is its I/O. There are six balanced XLR inputs and six balanced XLR outputs. Five of the outputs represent their corresponding inputs after the insertion of a highpass filter — instant 5.1 bass management. The sixth output represents the Infra subwoofer output for connection of another subwoofer. This Infra output is not just a lowpass filtered output, either; it represents the output of Bag End's proprietary Infra circuitry, which I'll discuss. The highpass filter causes the signal to roll off to 3 dB down at 130 Hz and to 6 dB down at 95 Hz, exhibiting a slope of 12dB/octave. The level of the five highpass-filter outputs is at unity gain, and the single Infra output represents the filtered and processed summation of all inputs.

The Bag End Infra technology is a sophisticated way of ensuring that the lowest lows are reproduced for you. The Infra dual integrator is a circuit that boosts low frequencies below resonance. All speakers naturally roll off in the low end, but this circuit emphasizes the lowest frequencies more as the frequency gets lower. For instance, it takes a certain amount of amplification to cause the driver to reproduce 20 Hz at a certain level. It takes much more amplification to cause that same driver to reproduce 10 Hz, and that is precisely what is accomplished by Infra. Strictly speaking, there is no true lowpass filter. The Infra dual integrator accomplishes the task of feeding the appropriately band-restricted signal to the driver. One positive result of this mechanism is the elimination of the long variable delay normally associated with a true lowpass filter. Thus, the acoustical output of the subwoofer is time-aligned with the output of the associated high-end system. The bass is also thus rendered tighter psychoacoustically. The dispersion of low-frequency energy is perceived to be tighter, better time-aligned and more consistent throughout its range.

The published frequency response of the Infrasub-12 subwoofer is 8 Hz to 95 Hz. There is a continuously variable level control for this sub, enabling the tuning of the system to the acoustical specifics of your studio and monitoring system. There's also a 10dB attenuator on the sub's number 6 input. The sub's lowest frequency can be switched from 8 Hz to 20 Hz, depending upon your needs. A dynamic filter circuit affords protection to the system, allowing you to monitor near the maximum level available without fear of damaging the driver or experiencing distortion. What's slick about this is that it doesn't just slam the entire subwoofer signal with a hard limiter; it limits only the lowest frequencies, which are inherently the most likely to do damage to the driver or cause audible distortion. This circuit effectively conceals an overload. The truth is, however, that it reduces the audible level of the lowest frequencies, which results in an inaccurate representation. For the benefit of mixing engineers in critical situations, Bag End provides a visual indicator that shows when the filtering is engaged. In most mix-monitoring scenarios, the circuit is not going to engage frequently unless the system is constantly pushed to its limits with excessive subbass program. The indicator LED is provided as a truth-in-advertising-type courtesy to discriminating engineers who really want to know the absolute truth about what's happening in the deep bass.


I set up this system in my control room and powered the M6s with the excellent Hafler TransNova P7000 amplifier. I sat down and listened to a broad selection of music from virtually all genres. I also fired up the Native Instruments Reaktor synthesizer to check out the superdeep bass of the subwoofer — which frightened my son and pissed off my wife! In my environment, I am very accustomed to my own monitors, on which I have tilted up the high-end response a bit. As a result, the M6s seemed a bit dull, but after listening for a while, I realized that I probably just have too much high end happening on my own monitors. One of the big reasons that I reached this conclusion is that I found the M6s to be far less fatiguing in the high end. The neodymium high-frequency drivers smoothly and pleasantly represent the highs; transient signals like hi-hats and other percussive elements are crisp without being brittle. Even after listening for quite a while, I had no significant fatigue, but I eventually realized that I was perceiving a slight bump right in the mids. It's definitely not a deal breaker for me, because it's not an overtly pronounced bump. I also perceived a slight lack of warmth in the low mids. The energy is being dispersed there, but it just didn't have that warm glow in that range. In defense of the monitor, however, this is really a result of its accuracy. The low mids are presented precisely as they really are, without coloration. It's funny how coloration has come to be accepted and even appreciated. But that's the point: These speakers tell it like it is.

The subwoofer is simply brilliant — no surprise — this is what Bag End is known for. The bass is deep and full while at the same time being tight. No resonant tubbiness is happening here. It's deep and punchy. Did I mention that it's deep? I cannot stress that point enough. It is simply deep. You've heard good subwoofers, but you haven't heard one like this.

Overall, the Infrasub-12 Pro and M6 combination is truly excellent. Across the frequency spectrum, the energy dispersion is consistent and pleasant. In particular, it's very revealing in the low end, which is important in today's electronic music. Bearing the price in mind, this is a solid system that I recommend considering. As a matter of fact, I prefer this to my own 2.1 monitoring system, which is quite good. Do I have to send it back?

Product Summary


M6 > $596 (each)

Infrasub-12 Pro > $1,980

Pros: Tight, full, deep bass. Accurate throughout frequency spectrum.

Cons: Amplifier required for M6. Almost too accurate; no warmth in the low mids.