Monday, March 16th, 2009 | by matthew mcglynn
At the NAMM show in January 2009, I was very impressed a bass-drum EQ device called the KickPort. I shot a little shaky-cam video of a drummer named Taz Roberson tearing it up. The kick drum sounded killer.
I bought a KickPort, and took some time to test it. My initial results were mixed — I proved that it’s doing something, but I was not convinced it was doing something I need. But my results were unsound, for at least two reasons: briefly, the KickPort imposes requirements on the resonant head that my reso head didn’t meet. Further, my early prototype KickPort appears to have been flawed in some respect, and was graciously replaced by the vendor, Future Percussion Concepts.
I’ve since done a lot more testing, and after many weeks’ delay I’m finally writing the review I wish I’d written in the first place.
The KickPort is a “tuned port” that can be installed in any bass drum head with a reinforced 5''–5.5'' port in the resonant head. It is essentially a flared plastic tube plus a clever mounting and sealing mechanism.
The flared end, which is backed by foam weatherstripping, seats against the outside of the drum’s front head. Midway down the tube is a flexible rubber ring (the only illustrative term that seems really accurate here is foreskin) that is folded back for insertion (bear with me), then flipped back up toward the head where it locks the KickPort onto the head from inside the drum.
It can be easily installed or removed without taking the head off the drum. (Flipping the rubber lip forward requires reaching through the port and lifting the lip with a pen or screwdriver. It’s easy, and it works.)
Its construction seems to be solid. It looks like it will survive many installations — and once installed, it will probably outlast the head.
I tested the KickPort on two drums: a 22''x16'' Tama Granstar II (7 ply, 9mm birch), and a 20''x16'' Taye Studiomaple (7 ply, 5.3mm maple).
The 22'' Tama had an Aquarian Super-Kick II batter head. This is a double-ply head with a “floating” felt muffle ring attached to the back side. The resonant head was a loaner from KickPort inventor Sammi Millender: a basic white 2-ply Remo Emperor, with a reinforcement ring around the port.
The 20'' Taye had an Aquarian Super-Kick I batter head. This is a single-ply version of the Super-Kick II. The resonant head was the stock crimp-lock Dynaton head that came with the kit. It’s a single-ply head with an internal “muffle ring” of head material around the circumference.
The KickPort is picky about resonant heads. If you use a damped resonant head, such as an Aquarian Regulator or Evans EMAD (with foam ring), you’ll get no benefit from the KickPort until you change the head. The KickPort is essentially one piece of a system. The other piece is an undamped resonant head. As FPC rep Jesse Bradman told me, “the user may have to adjust his/her rig to achieve best results.”
The KickPort documentation has been made more explicit about this issue, due, I think, to my initial inability to get a good sound out of the thing:
Please note that drum heads with felt or foam muffling rings on the resonant head will take away most or all of the great qualities of the KickPort — we advise removing the felt/foam or using another head.
KickPort Test #1 — 22'' Tama Granstar II
I did my testing in a 28'x15' room. It has a cathedral ceiling that peaks 12' off the floor. The room is not treated, but it’s big enough to let the drums speak. Acoustically, the drums sound great in the room.
I set up several microphones, because I wanted to know which ones would “hear” the EQ change from the KickPort. For example, would a mic inside the drum hear whatever EQ change the KickPort is creating?
Inside the drum was an AKG D112, shockmounted via the May mic-mount system.
The Avenson STO-2 is a condenser mic with remarkably flat response — within about 0.1dB of flat from below 20Hz to ~8kHz. Unlike every dedicated kick-drum mic you can name, the STO-2 is capable of hearing in glorious hi-fi every bit of EQ change the KickPort might produce, down to 20 Hz and probably even lower. I put this mic just inside the hole in the drum’s front head.
Outside the drum, I set up a CAD M179, a large-diaphragm condenser mic with extended low-frequency response. I set it about 16'' away from the resonant head, in Cardioid mode, pointing at the center of the resonant head.
I played a series of strokes on the drum, with and without the KickPort. From each group, I selected notes that were within about 2dB of one another in gain, then normalized them all individually (adding at most 1-2dB of gain). The result is a sequence of 4 notes without, and 4 notes with the KickPort, as heard by each of the three microphones.
From top to bottom, you’ll hear the D112 (internal), the STO-2 (in the port), and the M179 (external). Be aware that if you’re listening on tiny, underpowered speakers you’ll get less out of this test than you will if you listen through a playback system capable of low-frequency reproduction.
The KickPort produces an audible change within each sample. The drum sounds less boomy with the KickPort. The sound is tighter and punchier. And the low frequencies are more pronounced.
The LF shift is most apparent in the STO-2 sample — right in the mouth of the KickPort tube.
The KickPort really does bring out the drum’s low-end thump.
KickPort Test #2 — 20'' Taye
For the Taye test, I set up the M179 as on the Tama. Hear it in the top clip below. I added a Beyerdynamic M-380 (bottom clip), an oddball figure-of-8 dynamic that has earned cult status as a bass cab and kickdrum mic, thanks to praise from Steve Albini.
The M179 sample is especially revealing. The drum “before” has a nice punch, but a low-frequency ring that isn’t appealing. With the KickPort in place, the drum sounds slamming. The samples are at -6dB across the board, but the KickPort samples sound louder. The ringiness is gone.
A true comparison?
The above before-and-after samples are somewhat contrived, because not many drummers would play an undamped front head with no towel, foam, or pillow inside the drum. A more honest test would compare the muffled and damped drum to an empty drum with the KickPort on an undamped head. That way, the KickPort sample would have even more body and tone, in part due to the lack of internal muffling.
Nonetheless, I conducted these tests the way FPC did at NAMM: the only change from “before” to “after” was the insertion of the KickPort.
The point is that, depending on your kick drum setup, you may well hear even more dramatic changes than are suggested by the audio clips here. I started with a pretty dead kick drum, but this test has entirely changed the way I tune it.
KickPort Frequency Analysis
Jesse from FPC had told me that the KickPort causes a boost in low-frequency energy in the low 20Hz range. It does that for sure. In fact, mics that are capable of picking up lower frequencies show that the KickPort is creating another peak below 20Hz.
To see these effects, I imported single kick-drum samples into a frequency analysis tool. The plot from the STO-2 on the Tama drum illustrates the sort of change I saw in most of the mics: the peaks in the LF are shifted to lower frequencies by about half an octave. In most cases, I saw a flattening or reduction in sound in the 100Hz-500Hz range.
It’s very interesting that the three peaks in green describe exactly 2 octaves. I didn’t see the same pattern with all the mics, but then none of the other mics have such consistent low-frequency response.
What will those big blasts of sonic energy at 12Hz and 24Hz do for you? People in the room will feel ’em, but they won’t make your record. Engineers roll those frequencies off because most playback systems can’t reproduce below 40 Hz, although with a bit of gain they’ll sure sound crackly and bad trying to.
In most cases, those low frequencies won’t make it to a PA either, simply because kick-drum mics are EQ’d to have a LF peak at 50Hz, and roll off below that — see, for example, the D6, the Beta 52, or the N/D868. (The “chart” button on those pages will show you each mic’s frequency response graph.)
But the KickPort is clearly doing more than just creating frequencies only your subwoofer can love, or else you wouldn’t have been able to hear differences in the audio clips above.
In other words, a frequency-response chart does not tell the full story. It confirms that the KickPort is altering the frequency response of the drum. The KickPort is also altering the attack and sustain of the drum. Neither of those changes would show up on this graph, but I think you’ll hear them.
Hearing the KickPort in context
What does the KickPort sound like in the context of a full drum kit, with multiple mics happening?
|Aquarian ported, 4.75''||The hole is too small, and the felt ring must be removed.|
|Aquarian ported, 7''||The 7'' port is too large.|
|Attack resonant (Ported)||The 4'' port must be enlarged.|
|Evans Onyx Resonant||With a 5'' port, this head should work fine. The “control ring” might need to be taped down if it causes noise.|
|Evans EQ3||With a 5'' port, this head should work fine. Remove the “EQ muffle ring.”|
|Evans EMAD Resonant||The 5'' port will work fine. Remove the foam muffle rings.|
|Remo Powerstroke 3||With 5'' DynamO|
|Remo Ambassador (Ported)||The 5.5'' port is larger than ideal, but should work fine.|
|Remo Emperor||The 2-ply Emperor is one of the demo heads used by FPC; note that it will need a port cut and reinforncement ring installed.|
Note: the above table is a work in progress; I welcome corrections and additions. The general criteria a resonant head must meet are:
- Two-ply heads are preferred, but not necessary.
- The port must be 5-5.5'' in diameter.
- The port must have a reinforcement ring installed, both to prevent tear-outs and to give the KickPort something to grip.
- No foam or felt muffling is allowed. This is critical. Heads with built-in foam or felt, such as the Aquarian resonant, must be replaced or stripped of the damping materials.
- Perimeter rings of head material, as found on the Remo Powerstroke, are acceptable but these must occasionally be taped down to prevent rattling.