PreSonus: Temblor T8 Active Subwoofer

Last year, while Scott McChane was evaluating a number of affordable nearfield monitors for his home studio, we had a conversation about subwoofers. I'm a big proponent of using subwoofers with monitors that aren't purpose-built into the room (like soffit-mounted mains are). Scott, on the other hand, wasn't convinced that a subwoofer would help his mixing. When the opportunity arose to review monitors from the PreSonus Eris MTM family, I asked Scott to also give the PreSonus Temblor T8 subwoofer a try. I had purchased a T8 for my EDM-producing son a couple of years ago, so I already knew how effective it could be in a home studio. –AH

SM: A few months ago, I reviewed the Eris E66 active monitors [Tape Op #115] without the Temblor T8 subwoofer. Originally, I felt (and still do) that a nearfield monitor should stand on its own qualities. However, after less than three months of use with three different sets of nearfields in my project studio, I'm here to say that a carefully tweaked, inexpensive subwoofer like the PreSonus Temblor T8 can change your little world. I've had the opportunity to work in control rooms with soffit-mounted mains. Their big, full sound is quite emotional, and in my opinion, the simple addition of a subwoofer to your floating nearfield playback system can get you closer to that big production feel.

AH: Generally speaking, in a professionally designed facility, soffit-mounted mains are precisely positioned in a carefully treated room in an effort to attain the best possible frequency and time–domain response of the playback system. On the other hand, in a DIY project studio, the sound emanating from nearfield monitors positioned in free-space (on stands or on a meter bridge) will interact with all of the room surfaces in such a way that bass response will suffer. In other words, many DIY studios are subject to room resonances that cause serious dips in amplitude as well as pronounced ringing at low frequencies. This problem is exacerbated when speaker position corresponds to null points of the room's modal frequencies. To put it succinctly, the best position for nearfields to maximize stereo imaging and detail is rarely ideal for bass-response accuracy. To solve this dilemma, you need effective bass traps — but you can fit only so much trapping in a room. Another tactic to use alongside acoustic treatment is to separate the bass driver from the rest of the speakers, so you can generate the bass frequencies from an optimal room position. That's what you're effectively doing with a subwoofer.

SM: The Temblor T8 is designed to be a permanent part of a project-studio or editing-suite monitoring system. With the use of the Temblor's built-in crossover, setup is a snap — simply plug the outputs of your interface, mixer, or monitor controller into the T8's pair of balanced 1/4'' TRS or unbalanced RCA jacks, then patch the T8's TRS or RCA outputs to your nearfields. The T8's rear panel also offers a switch that enables an 80 Hz high-pass filter on the signal that you route to your nearfield monitors. A low-pass filter rotary control sets the upper end of the frequency range that the subwoofer will represent. In most instances, I preferred to set the LPF manually with the HPF off. Because its crossover controls are located on the back, like on most subwoofers, the T8 can be a bit of a bear to tune — but once it's right, it feels like it should be in-line all the time.

AH: Scott's preference for setting up the T8 so that his nearfields receive the full-bandwidth signal brings up another point. Instead of asking the subwoofer to take all responsibility for the bass frequencies in its operating spectrum, the subwoofer can be configured to augment the nearfields. Even if your nearfields reach down low enough for your needs, a strategically located subwoofer can help to reduce the aberrant low-frequency behavior brought on by room modes. Case in point, I have a pair of HEDD Type 30 monitors in my control room that reach down to 30 Hz. (I measured −3 dB at 30 Hz.) I borrowed my son's T8 and placed it in the corner of my room, where it could excite all room modes. With the feed to my HEDDs at full bandwidth, and listening at moderate volumes, the T8 was able to fill-in several room-mode valleys from 30–90 Hz, measured at mix position. On the other hand, my son has a pair of compact monitors, and in his room, the T8 is configured to handle everything below 80 Hz. This frees up his monitors to make more volume with less distortion, since they're not being tasked with generating the power-hungry sub-bass frequencies of his electronic music.

SM: The front power indicator lights the T8's PreSonus logo blue when powered on; while in sleep mode (in accordance with EU Power Efficiency Standards) the logo is white. I love that I can just leave the sub on all of the time (only consuming 0.5 W in standby) and not have to worry about groping around under my desk to find the power switch. With a powerful, yet tightly controlled, downward-firing 8'' glass-composite driver, and a compact front-ported cabinet (just under 12'' around all sides), the Temblor T8 offers a small footprint that won't get in the way physically or sonically (when used with taste and subtlety, of course). You don't see it or really notice it; you just feel it.

AH: The down-firing woofer was one of my primary reasons for choosing the T8. You can place the T8 anywhere, without fear of the driver being kicked in (or damaged otherwise). And despite its compact size, the T8 has significant reach. I measured −7 dB at 30 Hz. Contrast that to the frequency response of the much bigger Behringer B1200D-PRO that my son has for his live rig. Even with a 12'' driver, the Behringer's response is down −10 dB at 40 Hz. The T8 does have a slight resonance at 36 Hz (due to its driver/port tuning) that impacts its impulse response, but otherwise, it sounds relatively tight and controlled for a tiny cabinet with a long-excursion driver. The bigger brother Temblor T10 has a forward-facing 10'' driver, and PreSonus claims a frequency response down to 20 Hz. It also offers XLR I/O in addition to TRS, with a dedicated subwoofer output for daisy-chaining multiple subs, as well as a 1/4'' jack for the included subwoofer-bypass footswitch.

SM: In use, I never felt that the T8 was overcoloring the mix, so much as exposing when I went too far with bass guitar or kick drum levels — or when I just simply overhyped material below 100 Hz because I could not hear that detail otherwise. The T8's frequency response is listed as 30–200 Hz, and I did not feel that is a "hyped" specification, nor did I feel I need more low-end for my small project-studio space. True, I'm not getting down to 20 Hz with this sub, but 30 Hz is more bottom than most $500 nearfields can provide. The theory of having to "work for the mix" or make the mix sound good in a low-cost, band-limited monitor is valid, but given the choice, I'll take information over ignorance. With three sets of budget-friendly nearfield monitors on hand, I felt that the inclusion of the Temblor T8 to my system bumped those monitors into a higher class! Great work, PreSonus. Not a big-risk decision here. Highly recommended.