Installing Wheels

[yaggy]

I've always installed sturdy rubber
swivel wheels on all my cabinets. I can throw my
rack on top and just roll into gigs with extreme ease.
Novel idea, huh?

However, I believe I'm shortchanging myself in another
category. Despite the nods from other bassists, with
that "hey, that's a good idea" look, I think playing with
the cabinet raised off the ground is bad for my sound.

It may only be three inches, but by removing it and
practically isolating from being in contact with
the ground, I'm beginning to believe I lose low-end
replication and that gut-wrenching boom. True,
the house PA is doing all this for the room, but on-
stage and in practice, I feel weak. Hell, even the
house PA subs are sitting on the ground. No wheels
on them bad boys. Should I yank these off?
Perhaps a good idea would be to test my theory
by laying the cabinet on its side? Ah, but the
cabinets are ported at the bottom, so maybe
this won't be an effective test.

I can always grab a flat, wooden dolly to roll my
cabinets around on. But I want to get some
opinions from my veteran colleagues!

Thanks,
G

 

[billfitzmaurice]

by removing it and
practically isolating from being in contact with
the ground, I'm beginning to believe I lose low-end
replication and that gut-wrenching boom.

Only if those wheels are at least a foot or so diameter, and even then you'd only lose boundary coupling above 280Hz. Three inch wheels have no effect.

 

[Vanceman]

Maybe what your missing is the vibration coupling of the cab to the stage?

 

[billfitzmaurice]

Maybe what your missing is the vibration coupling of the cab to the stage?

He may, of course, but that brings up two other points. First, the walls of a properly constructed cab don't vibrate, so they also don't transmit vibration. Whether his cab is properly constructed is another question. Second, if the cab does vibrate it will only transmit vibration through an equally poorly constructed floor, though unfortunately that isn't the least bit uncommon.
Even in that case most of the vibration imparted to the floor is from the audio output of the cab, not via direct vibration from the cab walls. When this does occur the result is more often than not undesirable booming, and one of the cures for that is to lift the cab, not by inches, but by a couple of feet or so.

 

[Pilgrim]

Two things come to mind:

1) Removable casters.

2) Roll the rig in, then tip it over 90 degrees so it's laying on its side. See if it sounds different. I'll bet it's not significantly different.

 

[professor_bills]

My Guitar player has a combo unit with wheels in the side so when he tilts it it rolls but when he stands it up it is sitting on the floor. They look a little different from the little casters that came on teh bottom of My big cabinet So I imagine they were designed specifically to work that way. Plus if your cab is real heavy the screws need to be able to handle the sheer factor.
Or just buy a light weight handtruck.

 

[tallboybass]

Two things come to mind:

1) Removable casters.

2) Roll the rig in, then tip it over 90 degrees so it's laying on its side. See if it sounds different. I'll bet it's not significantly different.

I use the second method if more low-end is needed. Somehow it seems to help a little (mental?). With my UL410 it's not too often that more is needed, but outdoors it sounds better to me on it's side. YMMV. I LOVE being able to stack everything on the cab and roll it in.

 

[Bryan316]

I've got huge casters on my 212 cab now. I got sick of the push-in post-style casters, and got me four industrial 4" dia swivel casters. My cab is now a full 5 inches off the floor. I played at the I-Rock last night opening for Edguy, and even as high up as it is now, my rig was thundering, and not muddy.

I'm no longer concerned about wheel size and cab height off the ground. I just added a full 1-1/2 inches of gap between my cab and the floor and it still sounded awesome. Like Bill said, it's not the cab resonating into the floor, it's the speaker's output REFLECTING off the floor. If you're worried that your rig isn't loud and deep enough for you, then it's time to buy better quality cabinets. You are, after all, playing a Hartke cab.

 

[yaggy]

Thanks for all the information already! Wow.

You are, after all, playing a Hartke cab.

Ouch! Burn! Heh, yeah it's not top-of-the-line.
Well, it's actually top shelf of Hartke, compared to
their VX or Transporter series. Sounds decent on its own.

So the redirection here is, then, cabinet construction?

While many of the cabs only sound marginally different
at solo volumes (35% of pre-clip volume) they become
excessively different at performance levels? (85% of pre-clip)

 

[JonathanD]

Well, here is what I can contribute from my little experience.

With 2 acme 210 cabs and a stereo amp being feed by the same preamp.
stacked one on top of another they sound COMPLETELY different. I thought I blew a driver in the top one(CAB A) or something was wrong with the amp because it had so much less bass coming out of it. So I switched the speaker cables and the top cab still sounded a great deal less bassie and had more mid clarity than the bottom cab alone.

So I switched cab position and the top cab (now cab B) and it now had very little bass. This was on a wood floor in an apartmen at full volume (700 watts each cab.)

jonathan

 

[billfitzmaurice]

So I switched the speaker cables and the top cab still sounded a great deal less bassie and had more mid clarity than the bottom cab alone.

So I switched cab position and the top cab (now cab B) and it now had very little bass. This was on a wood floor in an apartmen at full volume (700 watts each cab.)

jonathan

What you think you heard isn't what you heard. With the two cabs stacked atop each other they mutually couple, in effect acting as one large cab, not two smaller ones, in the low frequencies. Their bass outputs are identical, and omnidirectional. What does differ is the midrange and high frequency output, which is very directional. You can't hear the midrange and high frequencies from the lower cab, because your ears aren't within their radiation pattern. You can hear the midrange and highs from the top cab that's closer to your ears. The psychoacoustic perception is that there's less bass from the upper cab, whereas in reality it's more mids and highs, not less bass.

 

[K2000]

With the two cabs stacked atop each other they mutually couple, in effect acting as one large cab, not two smaller ones, in the low frequencies. Their bass outputs are identical, and omnidirectional.

I've seen guys with two Ampeg 8x10s or two 2x15's lay their cabs on their sides, stacked one on top of the other. I've been wondering if that setup was better than having the two cabs standing side by side. Theoretically, the vertical speaker "arrangement" is still the same (8 speakers wide, 8 speakers vertical). So when stacking, the cabs do couple that way and provide an... audible... benefit...?

 

[billfitzmaurice]

I've seen guys with two Ampeg 8x10s or two 2x15's lay their cabs on their sides, stacked one on top of the other. I've been wondering if that setup was better than having the two cabs standing side by side.

Only if the cabs have tweeters and so doing places the tweeters in a vertical line; they'll work better than side by side. As far as the woofers are concerned, no difference, but it's a bad way to set up cabs. Horizontal dispersion is inversely proportional to the width of the radiating plane. Vertical stacking would be better, albeit precarious.