Coupling Vs. Decoupling

[TerribleTim68]

Interesting moment during the SBL "Heavy Metal Bass" course with David Ellefson, he discusses amps/cabs in the gear section and said he prefers to keep his cabs coupled because he feels it creates a resonance that can't be achieved by any other means. I had to pause for a bit because I see so many posts here saying "decouple your cab!" Interesting to hear what the pro guy whose been touring for decades says.

 

[Stumbo]

IME, you do whatever it takes to make the mix sound good. Go wireless so you can hear what the FOH/audience hears. Adjust from there. HPF, LPF, vertical stacks, wedges, tilted cabs, parametric eq, active bass...whatever works. Beat your rig and the room into submission.

 

[S-Bigbottom]

Stage boom can be good or annoying, like all sounds these things make it is players choice.

 

[Passinwind]

Interesting moment during the SBL "Heavy Metal Bass" course with David Ellefson, he discusses amps/cabs in the gear section and said he prefers to keep his cabs coupled because he feels it creates a resonance that can't be achieved by any other means. I had to pause for a bit because I see so many posts here saying "decouple your cab!" Interesting to hear what the pro guy whose been touring for decades says.

I happened to catch his clinic at the Tacoma Guitar Show when I was "working" there a couple of years ago. It went into a lot more technical depth than I expected and he kept it quite entertaining too.

 

[Zbysek]

I, too, prefer the sound of my cabs on the floor. I elevate them only in rooms where placing them on the floor causes problems...

 

[agedhorse]

It depends entirely on the situation and player preference.

 

[TerribleTim68]

I happened to catch his clinic at the Tacoma Guitar Show when I was "working" there a couple of years ago. It went into a lot more technical depth than I expected and he kept it quite entertaining too.

Ahh.....Tacoma Guitar Show. I was actually planning on going for the first time this year. Stupid Wuhan!

 

[Passinwind]

Ahh.....Tacoma Guitar Show. I was actually planning on going for the first time this year. Stupid Wuhan!

The one I went to was pretty good, hope to see you there in the future.

 

[Rockbobmel]

I have been using an Auralex copy for the last 5+ years Almost 100%. I tried it without for a few songs here and there and keep going back to it. Maybe I'll try it again if I ever get to play again. It seems that the bass sounds stronger in front and weaker out on the dance floor. Maybe I'll get better bass further out with the cab on the floor.

 

[bucephylus]

Speaker cabinets "couple" to the stage plate by way of the projected pressure waves emitted from the drivers into the air. The details about the coupling are somewhat complicated; but, the general degree of coupling initially increases as the cabinet is elevated off of the stage plate, reaching a maximum approximately 4" to 6" above the stage plate, and then decreasing as the cab is elevated further.

Since different stages have different resonant characteristics, it is unlikely to be able to identify an invariable optimal height. I would agree with Mr. Ellefson that some amount of coupling can reinforce the bass sound on stage / in the venue. Controlling that is where things get tricky. I too know of pro touring players who prefer some small amount of elevation; which itself is interesting; because as stated earlier, a small amount of elevation actually increases the coupling.

If any of you ever visit Frank Lloyd Wright's winter residence in Scottsdale, Taliesin West, you will see that even for a chamber quartet, Wright needed to specifically tune the characteristics of his stage in his "acoustically perfect" performance hall.

Ultimately, the player needs to work with the sound engineer and be prepared to change the elevation of any cabinets on stage to suit the mix. It is non-trivial, and this is one good reason that many stages have gone silent, using the developing preamp/DI technology with IEM's.

Edit: I should add that if your goal is to decouple the cab from the stage, then other than elevating it a foot or more, the other way is to put absorbing material, like a yoga mat in front of the drivers to soak up the pressure waves.

 

[TerribleTim68]

.... I would agree with Mr. Ellefson that some amount of coupling can reinforce the bass sound on stage / in the venue. Controlling that is where things get tricky. ...

I also wonder how much of his desire to create that is driven by his overall equipment choices. He prefers to use 8" speakers, so a stack of (2) 4x8 cabs is gonna have a different sound than a stack consisting of a 4x8 on a 1x15. So I wonder if he is using some of the coupling to return some bottom end that the lack of a 15 isn't delivering.

 

[Bass_Pounder]

I also wonder how much of his desire to create that is driven by his overall equipment choices. He prefers to use 8" speakers, so a stack of (2) 4x8 cabs is gonna have a different sound than a stack consisting of a 4x8 on a 1x15. So I wonder if he is using some of the coupling to return some bottom end that the lack of a 15 isn't delivering.

Speaker size alone does not dictate it's frequency response.

There are 10's out there that go way low, and there are 15's out there that are midrange monsters. The only thing the size of the driver tells you is the size of the speaker.

 

[zombywoof5050]

This article discussing mechanical and acoustic coupling may be useful here:
Stage Or Floor Coupling? The basics

 

[bucephylus]

This article discussing mechanical and acoustic coupling may be useful here:
Stage Or Floor Coupling? The basics

Alex is a good guy and makes excellent cabs; but, his page is a little misleading because what he refers to as mechanical coupling is insignificant compared to the Acoustic Coupling, which dominates the physics of the interaction. Like, by two or more orders of magnitude.

There are better references (which I am unfortunately not allowed to provide).

 

[TerribleTim68]

Ultimately it's all good conversation and I find it all mildly intriguing. I say mildly because I'm still not sure I'm sophisticated enough to even tell the difference. But that doesn't mean I don't find it fascinating on a certain level.

 

[Tim Skaggs]

I've always played with my cab on the floor. Anytime I tried to put a cab in a chair or on a table, it was like raising my high pass filter to about 150 Hz. It's something you get used to and it's hard to give up that low end reinforcement you get with a cab on the floor. I think that's always been why 810 cabs seem to sound better than their specs indicate they will. They are both floor coupled and have speakers up closer to your ears. It's probably why vertically oriented 4x10s or two vertically stacked 2x10s or 2x12s have become as popular as they are.

 

[TerribleTim68]

I've always played with my cab on the floor. Anytime I tried to put a cab in a chair or on a table, it was like raising my high pass filter to about 150 Hz. It's something you get used to and it's hard to give up that low end reinforcement you get with a cab on the floor. I think that's always been why 810 cabs seem to sound better than their specs indicate they will. They are both floor coupled and have speakers up closer to your ears. It's probably why vertically oriented 4x10s or two vertically stacked 2x10s or 2x12s have become as popular as they are.

That's an interesting take!

 

[JimmyM]

Interesting moment during the SBL "Heavy Metal Bass" course with David Ellefson, he discusses amps/cabs in the gear section and said he prefers to keep his cabs coupled because he feels it creates a resonance that can't be achieved by any other means. I had to pause for a bit because I see so many posts here saying "decouple your cab!" Interesting to hear what the pro guy whose been touring for decades says.

I haven't seen anything of the sort unless we're talking about uncontrollable boominess, in which case decoupling CAN work onstage. Only problem is that it takes like 2 1/2 feet or more to properly decouple a cab from the floor. And if you're onstage and the stage is elevated, it's pretty well uncoupled already.

 

[Stewie]

I have two identical SVT 15Es. The one on the floor (2 inch casters) produces a lot more bottom end than the one stacked on top, even if I switch their locations from top to bottom.
If I had three, the top one would point right at my head, I'd like that.

 

[zombywoof5050]

Alex is a good guy and makes excellent cabs; but, his page is a little misleading because what he refers to as mechanical coupling is insignificant compared to the Acoustic Coupling, which dominates the physics of the interaction. Like, by two or more orders of magnitude.

There are better references (which I am unfortunately not allowed to provide).

I've seen your research, so I don't doubt what you are saying, but that doesn't mean that mechanical coupling can't ever have it's own problems.