Auralex isolation riser

[Dale M Williams]

Anyone using this product, an Auralex Gramma? it is used to float an amp or loudspeaker. Many of the bars and clubs seem to have 6 to 12 inch high (cheap)staging. Too often my bandmates say my bass is a bit boomy or muddy. I don't want to lose any low end, so I thought I might give this a try.
Dale W

[lbpesq]

I have one.  It seems to do a good job of isolating the cab/amp from the ground.  I use it with guitar, not bass.  I haven't noticed any dramatic difference, but it does appear to be well designed and manufactured.  Of course there's not much to it - a platform on short foam feet.
 
Bill, tgo

[crobbins]

I use a milk-crate with my Markbass amp.

[mario_farufyno]

As far as I know, the destructive interactions that may occurs between Speaker and Floor happens by cancelations due to proximity, not by vibrations transfering. So looks more logical to just raise your Cab a little than using some kind of muffling or absorption pad.
 
I'm not sure about that, but seems that you never looses lows getting your Cab far from floor, you simply prevent from canceling some highs. So you're just hearing your Amp more flat as far as you take it away from surfaces. You can always use room to help fatten your tone, but preventing phase cancelations should allows you to get tighter lows (as far as your Cab can reproduce them, though). At least, this should makes you hear your Amp's tone with less room's coloration.
 
As any surface can act as a sound deflector, summing reflected sounds/frequencies out off phase with direct sound can always cut some of your highs out. To prevent boomyness I would first try raising it a little more or taking it far from close walls.
 
Changing place can be as effective as buying some other gadget (or more) and it's cheaper...

[cozmik_cowboy]

Top of a flight case works well, too.
 
Peter

[jazzyvee]

Do wheels on the cab have the same kind of de-coupling effect as raising it on a pad or milk crate?
 
Jazzyvee

[benson_murrensun]

I have heard of an acoustic phenomenon known as coupling, which has the effect of emphasizing bass frequencies. It occurs when the speaker is near to any single or combination of walls/floors/ceilings. I would think that getting the speaker off the floor in any way would reduce bass frequencies in the room. That is not to say that the Auralex device doesn't have other effects as well.

[edwin]

What Ben said is true. I got one of those a while back and noticed that it did make the bass less boomy on some stages. OTOH, I also noticed that on gig I did a few times on dock that was super flexible, it actually increased the low end. I think somehow a the cabinet was moving a lot (when the magnet and voice coil interact, the cabinet wants to move back when the cone moves forward) and the Gramma damped some of that motion. At least that's my theory. In any case, it sounded better. I stopped using it when I went to using a cabinet with casters, and that seemed to have a similar effect. Maybe I should drag it out again for when I use non-castered cabinets!