Auralex isolation riser Log Out | Topics | Search
Moderators | Register | Edit Profile

Alembic Club » Miscellaneous » Archive through October 01, 2010 » Auralex isolation riser « Previous Next »

Author Message
Username: rxbassman

Post Number: 30
Registered: 1-2004
Posted on Thursday, September 16, 2010 - 8:04 pm:   Edit Post

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
Senior Member
Username: lbpesq

Post Number: 4578
Registered: 7-2004
Posted on Thursday, September 16, 2010 - 8:22 pm:   Edit Post

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
Senior Member
Username: crobbins

Post Number: 682
Registered: 6-2004
Posted on Friday, September 17, 2010 - 6:32 am:   Edit Post

I use a milk-crate with my Markbass amp.
Senior Member
Username: mario_farufyno

Post Number: 529
Registered: 9-2008
Posted on Friday, September 17, 2010 - 7:19 am:   Edit Post

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...
Senior Member
Username: cozmik_cowboy

Post Number: 776
Registered: 10-2006
Posted on Friday, September 17, 2010 - 7:20 am:   Edit Post

Top of a flight case works well, too.

Senior Member
Username: jazzyvee

Post Number: 2139
Registered: 6-2002
Posted on Friday, September 17, 2010 - 11:55 am:   Edit Post

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

Advanced Member
Username: benson_murrensun

Post Number: 332
Registered: 5-2007
Posted on Friday, September 17, 2010 - 12:15 pm:   Edit Post

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.
Senior Member
Username: edwin

Post Number: 728
Registered: 5-2002
Posted on Friday, September 17, 2010 - 2:30 pm:   Edit Post

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!

Topics | Last Day | Last Week | Tree View | Search | Help/Instructions | Program Credits Administration