Facedown Bass Cab - good or bad idea?

[Mexay]

As the title says, if you add an extra cab to your setup (impedance aside) and lay it firing downwards on the ground, is there any risk to the gear in doing this?

I am trying to achieve a scenario where the bass is really felt and I wonder if firing a cab directly at the ground may do the trick. Something like a 15 inch cab, face down.

This would be in addition to a 212 and house speakers.

Is this likely to do anything? Am I going to bust my gear doing this or will I just look like a tosser?

Cheers in advance

 

[Old Garage-Bander]

You may get some bass coupling, but it may be at risk of damage to the facedown cab.
The obvious point of any cab is to move air. But the not so obvious consequence is that it may restrict the cone/voice coil/ports (if ported) from doing what they need to do to achieve "feel", that is to move air.

Trying to skirt around original design parameters in the usage of cabs is at best just an experiment.
At worst? Well hopefully that doesn't happen.

Suggest a stack of cabs, with the 15 (if it actually is the cab that can go lower) on the bottom.
The cab itself can achieve some coupling to the floor of the stage. But if the stage isn't well coupled to the room, you might not see (feel) much advantage.

 

[agedhorse]

Not a good idea, the speaker is no longer radiating into free air and this will change the air load that the speaker sees which will detune the cabinet. There's no way to predict its effect on displacement and thus power handling.

 

[Wasnex]

Acoustic Image used to make cabs that did this, and they sounded pretty cool. I have tried it with regular bass cabs, and the sound was worse than stacking the cabs in the normal fashion.

I think that having the driver shooting down could have an impact on how the cone centers in the voice coil gap. This could have a negative impact on performance and power handling. If you decide to try it, be conservative with how hard you push the down-firing cab...or maybe just don't.

 

[ebo]

I’ve been around here too long. I’m starting to understand the stuff that @agedhorse says.

 

[abarson]

Acoustic Image used to make cabs that did this, and they sounded pretty cool. I have tried it with regular bass cabs, and the sound was worse than stacking the cabs in the normal fashion.

I think that having the driver shooting down could have an impact on how the cone centers in the voice coil gap. This could have a negative impact on performance and power handling. If you decide to try it, be conservative with how hard you push the down-firing cab...or maybe just don't.

The difference with Acoustic Image is that it was designed to perform that way.

 

[agedhorse]

Acoustic Image’s execution is very different even if it seems similar.

 

[Redbrangus]

Yes, a very bad idea. As @agedhorse pointed out, the speaker will be operating into a virtually infinite load - kind of the acoustic equivalent of a dead short. The speaker will in no way perform as intended. The driver will probably couple to adjacent resonant masses more effectively just sitting on the floor in a more normal operating position and being acoustically coupled to the room. Or in other words, you'll end up just looking like a tosser.

I seem to remember reading that Neil Young used to use a Bandmaster cab lying face down on the floor and taking a bridged output direct to the PA. This was to achieve a particularly nasty distortion -- I expect this experiment would produce a similar effect.

 

[agedhorse]

Space it 6” off of the floor facing downward would be a better approach if you are focused on trying this.

 

[vvvmmm]

Might be louder on, say, a wooden stage than a concrete one ...

A weird OT story but I worked in a gas station with glass-doored bays, put my Pinto in one with some Sound Design 8" woofer 2-ways from a home stereo pointing a foot or two away from those glass doors, and had the cops there in about 5 minutes, said they heard "Slow Ride" a cuppla miles away. (Yeah, it was the late '70's.) Kinda wish I started with "Psycho Killer" ...

 

[JPK_DK]

I am trying to achieve a scenario where the bass is really felt

Maybe you could try one of these:

EICH BassBoard M | EICH Amplification

 

[Element Zero]

Do it. Film results and get back to us

 

[ga_edwards]

I am trying to achieve a scenario where the bass is really felt and I wonder if firing a cab directly at the ground may do the trick. Something like a 15 inch cab, face down.

This would be in addition to a 212 and house speakers.

A thought occurs. When you say "the bass is really felt", by whom should it be felt? Just by you, other band members or the audience as well? If the former, you may be better served by the EICH BassBoard mentioned above or BackBeat device.

If the latter, then let the PA do the heavy lifting. The ground coupling effect only reaches so far - I shudder to think of the volume and power required for other people to feel the bass just from your rig - especially at the back of the room.

I'm no expert in such matter, but from my limited understanding acoustics, one of the problems with intentionally exciting the floor to feel the bass is that it's unpredictable. Depending on what the floor surface is constructed of, and whether it's solid or hollow can play havoc with low frequencies. Mechanical coupling almost always results in unwanted "boom" and vibrations, which can also affect other instruments, particularly stationary vocal mic on stands. You might also encounter reflected frequencies that either cancel out making some notes disappear, or "one loud note" syndrome. This is why so many of us have embraced the humble HPF and even isolation risers.

Honestly, I think there's better solutions for what you want to achieve that won't wreak havoc with the mix and stage sound, and won't upset your band mates.

 

[Jay Corwin]

As the title says, if you add an extra cab to your setup (impedance aside) and lay it firing downwards on the ground, is there any risk to the gear in doing this?

I am trying to achieve a scenario where the bass is really felt and I wonder if firing a cab directly at the ground may do the trick. Something like a 15 inch cab, face down.

This would be in addition to a 212 and house speakers.

Is this likely to do anything? Am I going to bust my gear doing this or will I just look like a tosser?

Cheers in advance

What type of venues are you playing that you're worried about people not feeling the bass? When I was playing standard dive bars and rock clubs, a 4x10 with a decent head would just about blow the doors out if I felt like pushing it. Maybe you just need more fire power from a head? What is your rig?

Also, down firing speakers on crappy plywood stages sounds like an inherently bad idea, if those are the types of venues you are playing. Just my experience.

 

[Dynomuttasaurus]

I know from experience this can be done with a couple caveats. A few years ago, I worked a gala for the deaf. The sound guys brought in 5,000 watts of DEEP bass and a specialized cab/speaker system to shoot the vibrations straight into the floor for the audience to "hear" the music. Unfortunately, the exact cab design and signal equalization used is a mystery to me.

 

[Mexay]

This thread has been immeasurably enlightening.

As a few have guessed, I am looking to have the audience 'feel' the bass more, mainly in settings where there may not be fantastic venue sound, although the 'bass board' idea ks very cool.

From personal experience I know how great it is when you can genuinely feel the bass in your body and it tends to get people moving, which makes for a better gig. My thought process is "if I can reproduce this a little with just tacking on a cab pointed at the ground, it might make for better small-medium shows".

Interested to hear what others experiences are with this kind of thing though.

 

[Mike Mulligan]

When playing small venues (or even some larger ones) that have lousy sound systems (or sound men), I like to fire a cab at the back wall of the stage instead of the crowd. Obviously, this will vary with the particulars of the venue, but it can often achieve what I believe you are going for.

The house (or other cab, if stage mix) takes care of the tone and mix, the backward cab adds a ton of thump without overwhelming the overall mix.

YMMV, but it has worked for me!

Mike

 

[MultiScaleMale]

For a similar implementation, look at Boom Bass Cabs. Their Matrix, for example has a down-firing 15" and two front-firing 10" speakers. Interesting design, questionable build quality.

 

[Grinderman]

My first instinct or Scientific Wild Ass Guess IF I were to pursue this experiment would be to improvise, maybe with some cement blocks stack at the corners with protective wood blocks or plywood caps, to prop the cab up off the floor, face down, to fire toward the floor but providing air for the speaker/s to move.

If it the tested proved a worthwhile result I might design and build a sort of open coffee table or table frame (with no actual table top to cap it off), probably made to have an adjustable height off the floor, to create a downward facing cabinet stand.

I like Mike Mulligan's suggestion better, I'd have the cab backwards, firing at a wall be behind; a lot easier to do with less risk and probably more acoustic upside. (did I intend to make that pun?)

Either way, I suspect the construction of the stage or floor below or the wall behind would make dramatic difference in what you get. Thinking of solid constructed floor or wall cement, brick, block, and or tile vs hollow raised floor of wood or plywood subfloor, or hollow walls of sheet rock or plaster over wood studs; plus rugs, carpet, drapes, etc.

 

[Old Garage-Bander]

Might be louder on, say, a wooden stage than a concrete one ...

A weird OT story but I worked in a gas station with glass-doored bays, put my Pinto in one with some Sound Design 8" woofer 2-ways from a home stereo pointing a foot or two away from those glass doors, and had the cops there in about 5 minutes, said they heard "Slow Ride" a cuppla miles away. (Yeah, it was the late '70's.) Kinda wish I started with "Psycho Killer" ...

Always love a good Pinto story. With all that bass, at least the gas tank didn't think it was getting rear ended.
Owned three back in the day, between '72 and about '83. Two got rear ended, but never exploded. One was parked on the street, the other was being driven by the ex. (Not that I'd wish any ill upon her.)
I got some insurance money for the one on the street. The insurance company didn't take possession, letting me keep it. A neighbor then bought it to "fix" up but never did. Double win for getting rid of a rusty old bucket.

OK. Back to figuring out how to get a low groove to the elephants at the zoo.