DIY 'Gramma' isolation platform

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Peter Parker

Distinguished Member
I bought one of these for my Rel to limit an vibrations going through the floor in my loft. It appears to be made from 12mm MDF, carpet, dense foam and accoustic foam.

I wanted to do something similar with my main stereo speakers, so made two 'Grammas' using some MDF I had. I bought some cheap carpet from Carpet Right for £2.49 a square meter (£10 for a 4 x 1 meter length).

I found some very similar packing foam which is almost as dense and is similar to that found in tool cases - you cut it to shape for the tools etc. I also found some thick corrugated 'egg crate' style foam that looks similar, but probably has different properties. Try http://www.iplacoustics.co.uk fopr some 'profiled accoustic foam' which will probably do the job. I'm not sure where to get the thick dense foam strips from (4" x 2" on the Gramma, 3" x 2" on mine), but I'm sure a web search will find something similar.

here's a link to the pics in another thread:

http://www.avforums.com/forums/showthread.php?s=&threadid=127788&perpage=15&pagenumber=2

Gary.
 

Spligsey

Well-known Member
I'm looking forward to your " DIY Subwoofer" & "DIY Speaker" posts....

It would cost "less" than the cost of a new one.

Are you having a laugh?



Adz.
 

Phil Hinton

Editor
Staff member
Originally appeared on Secrets of Home Theater website
I'm pretty confident the GRAMMA can do no harm. But can it do some good?

I took an impromptu frequency response reading of my sub (gated, "quasi anechoic") while it sat on the floor, then again with it on the GRAMMA. No surprise: there was no difference and we shouldn't expect one. There was also no change in impact (back to what we were saying about "feeling it" in your chair). Lets be clear: the GRAMMA is not a tweak for your sub. It's better thought of as a treatment for your room!

What we did find is a slight tightening of the bass. Less "bloat". Less "fatness". Not that there was much to begin with:

Conclusions

A monumental-change-your-life-religious-experience? No.

So question has to be why waste your money.
 

bob1

Well-known Member
Originally posted by THX 1138
So question has to be why waste your money.

Isn't the point of the post to save money.
Plus you forgot to add in the conclusion
But at just $59 (regular A/V isolation platforms can cost hundreds of dollars), why not get one! Or maybe two if you have a Velodyne HGS-18 (JJ has four). It will also elevate your sub a few inches, something you should do in most situations anyway. If you've followed my writings at all, you know I'm a no nonsense kind of audiophile, constantly questioning the validity of expensive cables, black magic power conditioners, and anything with the word "tweak" attached to it. For what it's worth, the GRAMMA gets a thumbs up!
 

Ian J

Banned
Originally posted by Spligsey
So, what's your point Mr Lightfoot?

His point was probably the same that MuFu made some time ago when he said that he had made a "subwoofer isolation panel" out of an old wooden door and some carpet tiles and having "upgraded" that to the real McCoy could hardly tell the difference.
 

avanzato

Active Member
Originally posted by Spligsey
So, what's your point Mr Lightfoot?

The Secrets review was hardly the most conclusive I've ever read as the conclusion was "it's so cheap", "it can't do any harm" and err "you might as well try one"

Garys is even cheaper so on that basis is even better.

Why do you feel the need to snipe at Garys post?
 

buns

Banned
If some of us were more honest with ourselves, alot of the 'upgrades' we make are barely noticeable, but we still make them. Thats the point :)

ad
 

Peter Parker

Distinguished Member
Well, I believe there's a lot of 'snake oil' in home cinema products, and a lot of people spend a lot of money on things that in reality make no difference. Placebo has a great deal to do with percieved performance and that's what the manufacturers rely on.

Projector ceiling mounts generaly cost around £150, yet a metal speaker bracket with similar functionality can cost as little as £12 - and you get two of those!

In this case, I've isolated my main speakers and saved £100 from buying two products that will do the same job. Now that I have two subs, I'll make two more - as I've only had to buy carpet, the cost of each 'Gramma' to me is only £2.50. I'll use the existing one for the center, unless somebody wants to give me £55 for it (Spligsey?) :D

Gary.
 

Spligsey

Well-known Member
Originally posted by avanzato
The Secrets review was hardly the most conclusive I've ever read as the conclusion was "it's so cheap", "it can't do any harm" and err "you might as well try one"

Garys is even cheaper so on that basis is even better.

Why do you feel the need to snipe at Garys post?


Dont confuse me with someone who cares.

I am just lodging my thoughts


Adz
 

Spligsey

Well-known Member
Originally posted by Ian J
His point was probably the same that MuFu made some time ago when he said that he had made a "subwoofer isolation panel" out of an old wooden door and some carpet tiles and having "upgraded" that to the real McCoy could hardly tell the difference.


Cheers Ian


Adz
 

rags

Well-known Member
I have a gramma which sits on an old wooden floor - it definately has improved things - the floor rattling has been greatly reduced and the door that is located close to the sub no longer vibrates.

For me was worth paying £50 for as I have about a zero chance of making it myself. Im sure that other more DIY competent people could easily construct an effective version themselves.
 

Peter Parker

Distinguished Member
DIY varies from person to person, and we all have our limits.

What someone can do, there are others that can't, so there's no dishonour in having to buy things because you're not confident in doing it yourself or haven't the time, regardless of how easy someone else may say it is. Cost isn't necessarily an issue in that case either.

What I can't understand is why someone should take offence at someone who's trying to help those who are capable and want to have a go and save themselves some money. Surely, given the choice, we'd all like to get things cheaper wouldn't we? Actualy I do understand the reason but I dunno if I should let on...

Anyone thinking of buying some Mopads to isolate their speakers? Save yourself over £30 and go into Jessops and look at their bags of case foam (not the diced stuff) - some looks identical in construction to the Mopads and only costs £7.50. I'm willing to sell this at a huge profit to anyone who wants it (I'll get a closer look and feel next time I'm near the place).

Bugger. Just given my secret source away.. ;)

Gary.
 

mw3cdj

Standard Member
Gary,
Good idea mate,
As my sub sits an a marble slab at the moment, do you think that if i used some mopads to isolate the marble from the floor this would cut down on room vibrations for me. Got plenty of spare mopads in work ;-)
Regards
Daran
 

avanzato

Active Member
Looking at their spec the Mo-pads have a weight limit of 100lbs. I guess if you can fit enough under the marble slab to support the weight of it and the speakers then they'll work just fine. Is there enough room to put a pad under each corner of the slab? Or cut them to size. So long as the speaker isn't wobbly it seems like a good idea.
 

Peter Parker

Distinguished Member
If you've plenty to spare, you've nothing to lose, but they should help stop some of the vibrations if nothing else. :)

Gary.
 

Stuart Wright

AVForums Founder
Staff member
Originally posted by Spligsey
Dont confuse me with someone who cares.

Seems to me you care enough to be confrontational.
Perhaps it's because you spent money on buying the product that it upsets you that someone can offer ideas for a cheaper alternative.
You've contributed nothing useful to this thread.
 
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