TC Electronic RS112: Port-Stuffing to cut boominess

[Rick Auricchio]

I just bought a four-inch foam ball to use as a port plug on my RS112s. Plugging the port cuts boominess, especially when the rear port is close to a wall.

Port-plugging will alter the cab tuning; this weakens deep bass and will slightly flatten the low-end rolloff slope.

The foam ball I chose (a Poof 4" mini basketball) is more dense than a Nerf foam ball, but not nearly as dense as rubber or plastic balls. It just fits the port on the RS112. (I don't know the port size on the RS210 or RS212.)

It cost about four dollars at Walmart, and I presume it can be found in many toy stores. I chose the black/neon-yellow color.

If the ball falls into the cabinet, it won't cause any damage, and you can easily reach in and get it out.

[Jazzdogg]

Interesting. Have you tried it on a gig with the port stuffed yet?

[billfitzmaurice]

Inserting a longer snug fitting tube into the duct would lower the cab tuning and tame boom without robbing response below the boom frequencies.

[nostatic]

Originally Posted by Rick Auricchio

I chose the black/neon-yellow color.

I hear the red ones sound a lot better

[Rick Auricchio]

Thanks, Bill. I'll hunt down a tube of some sort! If the tube extends outside the cab, does that count? It's easier to handle that way.

I haven't yet tried the cab on a gig; that'll happen on April 5th. The cab will be about six inches from the back wall, so I might need to tame it a bit. Of course, there's also EQ, but I'd like to have a solution that's trivial to put into place.

[billfitzmaurice]

Originally Posted by Rick Auricchio

If the tube extends outside the cab, does that count?

Even better. The cab booms because it's too small.

[Smallequestrian]

I'm surprised you find that cab boomy (outside of the port against the wall aspect).

[Rick Auricchio]

Like I said, I haven't yet gigged it. I'm only listening at reasonable volumes in my garage, in an area where the ceiling is short of 8ft. That's going to give me standing-waves somewhere above 80Hz, which could be the issue.

The gig is small and not loud, so I'll get a chance to really listen to the cab in a live situation.

[nostatic]

Not quite the same cab, but I find my Berg AE112 to be a bit boomy if I'm up against a wall (it's rear ported as well).

[Musicman20]

I think all cabs prove boomy in certain environments. I suggest a Gramma pad perhaps?

[The Diaper Geni]

Originally Posted by Musicman20

I think all cabs prove boomy in certain environments. I suggest a Gramma pad perhaps?

Or an amp stand. I use an amp stand (almost) all the time. Prevents "boominess" and I play at a lower volume becuase I can hear myself better (which in turn helps the FOH sound).

Also a Gramma or amp stand will make your tone more consistant from room to room. Of course IMO and etc apply. But I likey!

[chiplexic]

Originally Posted by nostatic

Not quite the same cab, but I find my Berg AE112 to be a bit boomy if I'm up against a wall (it's rear ported as well).

If the AE112 speaker is related to the Eminence DeltaLite 2512 I can see it being boomy. Does Jim use Eminence?
I know he must tweek the specs to his design goal. But I wonder if it's related to the 2512.

I get a boom around low-mids using the 2512. Around 82hz in 2.1 cu.ft cab tuned to 52hz. Wonder what that AE112 is tuned to and who it's sourced from?

[billfitzmaurice]

Originally Posted by chiplexic

If the AE112 speaker is related to the Eminence DeltaLite 2512 I can see it being boomy. Does Jim use Eminence?
I know he must tweek the specs to his design goal. But I wonder if it's related to the 2512.

I get a boom around low-mids using the 2512. Around 82hz in 2.1 cu.ft cab tuned to 52hz. Wonder what that AE112 is tuned to and who it's sourced from?

I can't speak to specific cabs, but there are two recurring common themes to bass cab design that are fairly ubiquitous. One is making the cab too small for the drivers inside. The other is tuning it too high. Both are the result of giving the customer what he wants, which is the smallest yet loudest cab possible. What's traded away to get that is solid low end, what you get in return is a tendency for the cab to boom, especially when the room acoustics encourage it.

[Rick Auricchio]

I don't think a gramma will help. The rear port will have far more influence against the wall than the stage-riser.

And, just to repeat, I haven't actually used the cab at the gig. I was just coming up with a quick way to "softly" block the port, anticipating it as a usable remedy in some situations.

Based on Bill's recommendation, I found a six-inch plastic can that fits as a port-extender. It does the job---though it makes the cab even longer than it is. And since the original problem was being too close to the wall on a shallow stage, the extender eats up more stage space. So I have both the extender and the foam-ball plug in case I need them.

As for amp stands, most are designed for cabs that are shallow and wide (like a guitar combo). The RS112 is 14" wide and almost 17" deep, exactly the wrong shape for most amp stands. Besides, boominess from floor coupling isn't mitigated till you get the cab a few feet up.

Edit: The cab is 19.5" deep, and we add three more inches for the Speakon cable.

[nostatic]

Originally Posted by billfitzmaurice

I can't speak to specific cabs, but there are two recurring common themes to bass cab design that are fairly ubiquitous. One is making the cab too small for the drivers inside. The other is tuning it too high. Both are the result of giving the customer what he wants, which is the smallest yet loudest cab possible. What's traded away to get that is solid low end, what you get in return is a tendency for the cab to boom, especially when the room acoustics encourage it.

I should point out that this only really happens when it is right up against a wall. Outdoors the cab is perfect, and indoors as long as I've got a few feet it is fine. I also can pretty easily eq it with the TC head.

The other data point is this is my first cab with 12s (always had 10s before) so it also might be the inherent character of the speaker that I'm conflating with the placement and tone.

The length of the RS112 was one of the things that turned me off the design actually. I often play in fairly tight/odd places and 2" can make a difference.

Hmm, where have I heard that before...

[Rick Auricchio]

+1. This is only something to consider when the port is very close to the back wall. At this gig, I can get perhaps six inches' space to the back wall, otherwise I'll be falling over the cabinet!

My prior cab was the Eden D112XLT, which has front ports and far less low-end extension.

I was wondering about finding/building some type of exotic stand that would hold the cab at a steep angle, 45 degrees or a bit steeper. It would almost look like a conga drum, with the driver facing upward. It'd certainly be an eye-catcher. No idea where I'd put the amp head...

[nostatic]

Originally Posted by Rick Auricchio

+1. This is only something to consider when the port is very close to the back wall. At this gig, I can get perhaps six inches' space to the back wall, otherwise I'll be falling over the cabinet!

My prior cab was the Eden D112XLT, which has front ports and far less low-end extension.

I was wondering about finding/building some type of exotic stand that would hold the cab at a steep angle, 45 degrees or a bit steeper. It would almost look like a conga drum, with the driver facing upward. It'd certainly be an eye-catcher. No idea where I'd put the amp head...

I've played gigs with the head sitting on its side on the floor with me sitting on the cab. I have the footswitch so no real need to look at the head except to maybe set master.

The design aesthetic of the RS cabs would work well with some sort of funky stand. The shape of the RS112 makes it a little less obvious that is *should* be setting flat. I think of it kind of like a torpedo. With a big bottom. (cue the music)

[jnewmark]

Originally Posted by The Diaper Geni

Or an amp stand. I use an amp stand (almost) all the time. Prevents "boominess" and I play at a lower volume becuase I can hear myself better (which in turn helps the FOH sound).

Also a Gramma or amp stand will make your tone more consistant from room to room. Of course IMO and etc apply. But I likey!

+1. Been using an amp stand for years for my smaller cabs, and my Roland DB 700 combo. One thing I have noticed for sure is my tone being consistent from gig to gig. With my 212 and my 215, on the floor, not so much.

[Jazzdogg]

Originally Posted by billfitzmaurice

Inserting a longer snug fitting tube into the duct would lower the cab tuning and tame boom without robbing response below the boom frequencies.

My home stereo subwoofer (B&W) came with several tubes of different lengths with which its response can be adjusted to suit the room in which it's being used.

I'd be curious to hear how the response of the RS112 might be changed using tubes of various lengths.

[Rick Auricchio]

I'll play around trying funky almost-vertical stand arrangements. Maybe even vertically like a conga? That would really confuse people. Can't hurt to try.

It would be nice to experiment with tuning by extending the port. But that makes the cab even deeper than its 16.5" depth, which is already a drawback on a shallow stage. Maybe an elbow to turn the extension vertically? Bill will get a chuckle at that.

First guess at a stand: see attached photo! Rip out the burner and it's sturdy enough to hold the 30lb cab. These fryers are often cheaper than buying something from a music store.