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Amp/Cab Isolation configuration question

Lumpy_Bass

Lumpy_Bass

Jun 8, 2010
196
11
Hockessin, Delaware
www.instagram.com
#1
What's up TB,

I know this has been addressed in this forum numerous times but I wanted to get advice on my specific setup. I am running a a Hartke HA2500 to a hartke 210VX and 115XL. When I do smaller gigs I use just the 210 and if space permits I set it on this stand:
46728b9a-2336-4ceb-9f30-93a253788826_300.jpg

I have an outdoor gig on a raised stage (about 4 feet) that I know is especially boomy being as this is our 4th year at the venue. I have 2 of these stands and I am considering elevating both cabs side by side with the amp on top of the 210.

Will this significantly reduce my boominess? Does anyone have any other suggestions for how I should configure using these pieces?

Any and all input is appreciated.

Thanks
 
#8
Vibration isolation is pretty straight forward - it is done in industrial applications for machinery all the time. Doing it for a bass rig is trivial, but requires some calculation.

With a known weight for your rig you want to set it on a spring that has a resonance [under load] that is a few octaves below the lowest resonance you wish to isolate. This would not be difficult using durable visco-elastic blocks such as this material.

http://www.google.com/search?q=sylomer

If you contact a dealer with the details of weight for the rig and lowest desired isolation frequency they should be able to spec a set of pads for your rig that will decouple the rig for any stage boominess arising from mechanical resonance transference. For acoustic coupling you'll still have to fiddle with the EQ but that is probably a small fraction of the problem in the situation you describe.
 
#9
RickenBoogie said:
A graphic eq is even easier to dial out the boomy frequencies. Just stack the speakers atop each other with the head and rock out. Use your graphic eq to reduce the offending frequencies.
Click to expand...

Bands on a graph can be a fairly large frequency area though, with a full parametric you can use the Q to control a narrower bandwidth if that's all that's needed (I'm sure you know how a parametric works by the way, couldn't think of any other way of saying it...)
 
#10
Foz said:
Vibration isolation is pretty straight forward - it is done in industrial applications for machinery all the time. Doing it for a bass rig is trivial, but requires some calculation.

With a known weight for your rig you want to set it on a spring that has a resonance [under load] that is a few octaves below the lowest resonance you wish to isolate. This would not be difficult using durable visco-elastic blocks such as this material.

http://www.google.com/search?q=sylomer

If you contact a dealer with the details of weight for the rig and lowest desired isolation frequency they should be able to spec a set of pads for your rig that will decouple the rig for any stage boominess arising from mechanical resonance transference. For acoustic coupling you'll still have to fiddle with the EQ but that is probably a small fraction of the problem in the situation you describe.
Click to expand...

This is the type of suggestions I was looking for. Thank You. Now, where the heck can I find this, or something similar quickly as the gig is Friday:help:
 
#11
Can't promise it'll work but for a down and dirty, from your local big box hardware store, get some medium squishy EVA foam pads as are sold in interlocking jig-saw puzzle like pieces meant to add an anti-fatigue / cushion floor to lay on concrete floors.

Stack a couple of these up and set your rig on top. You might need to do some cut outs on the top layer for the feet/casters to spread the weight around more evenly and get a stable stack. In a perfect world the right foam to get a very low resonance spring would deflect maybe as much as 10% from full height once the weight of the rig was added - but random store bought pads may be too stiff [or too soft] to achieve the proper result. Might do in a pinch - but would not be as good as a properly engineered solution. If you contact a dealer they can calculate your needs with high precision and sell you a pad of the proper thickness and stiffness [durometer/ shore number] for optimal results.
 
#13
Foz said:
Can't promise it'll work but for a down and dirty, from your local big box hardware store, get some medium squishy EVA foam pads as are sold in interlocking jig-saw puzzle like pieces meant to add an anti-fatigue / cushion floor to lay on concrete floors.

Stack a couple of these up and set your rig on top. You might need to do some cut outs on the top layer for the feet/casters to spread the weight around more evenly and get a stable stack. In a perfect world the right foam to get a very low resonance spring would deflect maybe as much as 10% from full height once the weight of the rig was added - but random store bought pads may be too stiff [or too soft] to achieve the proper result. Might do in a pinch - but would not be as good as a properly engineered solution. If you contact a dealer they can calculate your needs with high precision and sell you a pad of the proper thickness and stiffness [durometer/ shore number] for optimal results.
Click to expand...

That is whatIi was thinking. I actually think I may try 2 or 3 layers of the pads under the tops of the stands shown in my first post and then the cab to give it lift and then absorption. Thanks for your help. I will post on Monday with results.
 
#15
SwamiRob said:
Link Removed

That's non DIY, but probably considerably more expensive, alternative if you find yourself in too much of a rush. The DIY method will be better when done properly I'd imagine though.
Click to expand...


But they are kinda pricey...
I've actually been mentally planning out building one of these on my own I just haven't had the time to gather the materials and work on it.

From what i can tell it's basically 2x4's and plywood cover with wool felt with a wedge of soundproofing foam attached to the bottom. Well the gig is tonight so I'll post tomorrow with how the fatigue pads worked out
 
#18
SwamiRob said:
Bands on a graph can be a fairly large frequency area though, with a full parametric you can use the Q to control a narrower bandwidth if that's all that's needed (I'm sure you know how a parametric works by the way, couldn't think of any other way of saying it...)
Click to expand...

I use both, graphic and parametric, EQ's. Graphic EQ's are not specific enough to isolate only one frequency. You take down one slider and you'll be taking down other adjacent frequencies along with it. With a parametric you can actually isolate one frequency and remove it without affecting others.

I like to use both for tone shaping, and then use the graphic to narrow an offending group of frequencies and then fine tune it with the parametric. I hate to have a room totally dictate to me what kind of tone I can have, so using both helps me find a balance between my tonal goals and what the room allows.
 
#19
Well IMHO I think there was a definitely an improvement in my tone with the use of the padding. I got these from a local retail chain.

10080112124?hei=600&wid=600&op_sharpen=1&qlt=90,0&resMode=sharp&op_usm=0.9,0.jpg


They are 2X2 and my cab is 24" so that worked out great. I just taped the whole stack together with duct tape so my total cost was under $20.

We ran our own sound on Friday and I definitely noticed a difference. My sound was only coming from my cabs (no DI, mic etc.) and I definitely noticed more clarity and less mud than in prior years there. I also used the pad on my Saturday gig which was on one of those 6 piece portable stages that are about 12 - 18" off the ground. This was also a notoriously muddy and tone stealing stage. Again, definite improvement and even the sound guy said he noticed a difference. I did not have the opportunity (or time!) to do any sort before and after comparison but at this point I do forsee this little pad stack as new addition to my live setup.
 

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