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An inexpensive speaker tweak that works!
Old 27th July 2017
  #361
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bino_5150's Avatar
When I built my custom monitor stands for my satellite monitors, I put a layer of Dynamat, then a layer of foam under-carpet padding, and then a layer of the foam/rubber anti-slip drawer liner like rds did. Seems to do the trick for me. Very inexpensive and effective.

What also made quite a bit of difference is I covered my desktop with that drawer liner as well. Really helped clean up the highs since the desktop was between me and the monitors.
Old 28th July 2017
  #362
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It seems to me that the most important thing is that the speaker does not move. Even if there are multi-layers of damping or whatever under the speaker the only thing that counts is if you walk up to the speaker and push it very firmly from the front and the back there should be no movement. If there is movement heavy bass or high volume will cause some smearing of the sound. Some people think that spiked speakers are preferred to decoupled speakers.
Old 28th July 2017
  #363
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Quote:
Originally Posted by sd270 View Post
It seems to me that the most important thing is that the speaker does not move. Even if there are multi-layers of damping or whatever under the speaker the only thing that counts is if you walk up to the speaker and push it very firmly from the front and the back there should be no movement. If there is movement heavy bass or high volume will cause some smearing of the sound. Some people think that spiked speakers are preferred to decoupled speakers.
I'm not so sure about this. If a speaker is on a completely rigid platform then it creates a flanking path for vibration. Just like if you tap a hammer on very thick concrete, you can hear the tap the other side. If however the speaker is on a platform that can swing, but has sufficient mass, it forms a mechanical high pass filter. If that filter's roll off is below the low frequency limit of the speaker then no vibration from the speaker should pass and it shouldn't be excited by it either.

Essentially, I'm suggesting ( with very limited engineering knowledge admittedly ) that a flexible platform for a monitor to sit on could be advantageous. It was a recent reading of the BBCs research into thin, but heavily damped, loudspeaker cabinet panels that got me thinking about this.
Old 10th March 2019
  #364
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bumping this old thread but i'm trying to decide whether to go for the cheap pads recommended in this thread or something a bit more expensive, like these ones: ISO-L8R<font style="font-size:15pt">155</font> Isolation Stands for Speakers and Studio Monitors | IsoAcoustics
Old 10th March 2019
  #365
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Quote:
Originally Posted by GJ999x View Post
bumping this old thread but i'm trying to decide whether to go for the cheap pads recommended in this thread or something a bit more expensive, like these ones: ISO-L8R<font style="font-size:15pt">155</font> Isolation Stands for Speakers and Studio Monitors | IsoAcoustics
I use those with my KEF LS50s, very good. Not compared directly vs sorbo (which I use for the Kii's).
Old 12th March 2019
  #366
nms
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Quote:
Originally Posted by GJ999x View Post
bumping this old thread but i'm trying to decide whether to go for the cheap pads recommended in this thread or something a bit more expensive, like these ones: ISO-L8R<font style="font-size:15pt">155</font> Isolation Stands for Speakers and Studio Monitors | IsoAcoustics
Perfect example of the fact that paying more doesn't ensure a better product.

More studio designers will advocate a properly load matched sorbothane config over those. Thomas Jouanjean of Northward Acoustics being one compelling example.
Old 10th December 2019
  #367
Here for the gear
 

Hello all! Reviving an old thread here.

Our studio has had a custom welded steel stand for years that borrowed the isolation element from recoil stabilizers. Basically we have a steel plate spanning the meter bridge, then a layer of 2” open cell foam, then another steel plate, followed by a neoprene mat. This has worked fairly well for us over the years, but we recently upgraded our speakers with an order of ATC scm50asls and I need to modify the stand to make it work correctly. Since we’re going through the modification I’m considering losing the layers and just doing 2.5” 30 duro sorbothane pads on the main steel support. Any thoughts of that would be better, the same, or worse? Fwiw I think the speaker height would be slightly better with the sorbothane....

Adrian
Montroserecording.com
Old 10th December 2019
  #368
Gear Addict
SCM100's on 2.5” 30 duro sorbothane pads (5 each) over here.
Got them on a custom fabricated solid steel stand and it works fine, although the pads are extremely squashed down.
Makes me wonder how long these pads will keep their isolating properties.
Old 10th December 2019
  #369
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Deckdaddy's Avatar
The pads under my Kii Threes are squashed as well, works great though.
Old 11th December 2019
  #370
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Quote:
Originally Posted by aolsen View Post
Hello all! Reviving an old thread here.

Our studio has had a custom welded steel stand for years that borrowed the isolation element from recoil stabilizers. Basically we have a steel plate spanning the meter bridge, then a layer of 2” open cell foam, then another steel plate, followed by a neoprene mat. This has worked fairly well for us over the years, but we recently upgraded our speakers with an order of ATC scm50asls and I need to modify the stand to make it work correctly. Since we’re going through the modification I’m considering losing the layers and just doing 2.5” 30 duro sorbothane pads on the main steel support. Any thoughts of that would be better, the same, or worse? Fwiw I think the speaker height would be slightly better with the sorbothane....

Adrian
Montroserecording.com
Sorbothane will work great, but you need to get the load and weight distribution right.

In your case you don’t really need to add any additional weight to the speaker to make it work. All you need is 4 of the 2.5” 30-duro hemispheres and you will be in the sweet spot.

One 2.5” 30-duro has a sweet spot between 25-35 lbs so 4 of these will have a sweet spot of 100-140 lbs. SCM50ASL is 107lbs so you are good to go.

If the monitors are front heavy position the hemisphere closer to the front so the weight is distributed evenly on all 4 pads.

One thing to watch out for is that you don’t really want a direct contact between sorbothane and the paint of the monitors. Sorbothane is a chemical that will slowly react over time and maybe you will have permanent spots from them. So just place something in between.
Old 11th December 2019
  #371
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happy to see this thread back in action - I'm going to get some sorbothanes for my APS Aeons (18kg / 40lbs)

I reckon I'll go for four 2"/30 duro each (11-16 lbs) for a range of 44-64lbs, sweetspot 54lbs/24kg

Then to make up the extra weight to be in the sweet range I'll put a circular barbell weight like 5 or 6 kg or 10lb or 14lbs(1 stone) on top of the speaker, with blutack.

initially I'll carefully (ie very hands-hovering!) experiment with balancing the speaker on a pencil or some kind of little rod, as a roller, halfway back, just to see how the weight distribution goes between the drivers at the front and the amps at the back.

Then with a bit of fiddling I ought to be able to position the weight to make the weight distribution even.

I might even be as organised as to do before/after rew measurements. we'll see...
Old 11th December 2019
  #372
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Quote:
Originally Posted by mutetourettes View Post
happy to see this thread back in action - I'm going to get some sorbothanes for my APS Aeons (18kg / 40lbs)

I reckon I'll go for four 2"/30 duro each (11-16 lbs) for a range of 44-64lbs, sweetspot 54lbs/24kg

Then to make up the extra weight to be in the sweet range I'll put a circular barbell weight like 5 or 6 kg or 10lb or 14lbs(1 stone) on top of the speaker, with blutack.

initially I'll carefully (ie very hands-hovering!) experiment with balancing the speaker on a pencil or some kind of little rod, as a roller, halfway back, just to see how the weight distribution goes between the drivers at the front and the amps at the back.

Then with a bit of fiddling I ought to be able to position the weight to make the weight distribution even.

I might even be as organized as to do before/after rew measurements. we'll see...
Best to try before you make up your mind. The Sorbathane mentioned in my first post works GREAT but as others have pointed out there are many different ways of using it. If you buy it from Amazon you have 30 days to return it if it does not do what you want it to do. I have a good friend who built himself some amazing speaker stands out of cinder blocks, sand and plywood and they worked well but the thing that made them sound AMAZING is when he used Sorbathane under his speakers. Quite an improvement. FWIW
Old 11th December 2019
  #373
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Thanks!

Thank ya! Ordered 2.5 30 duro pads and will see what happens!
Old 12th December 2019
  #374
Deleted 307cb3c
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Quote:
Originally Posted by mutetourettes View Post
happy to see this thread back in action - I'm going to get some sorbothanes for my APS Aeons (18kg / 40lbs)

I reckon I'll go for four 2"/30 duro each (11-16 lbs) for a range of 44-64lbs, sweetspot 54lbs/24kg

Then to make up the extra weight to be in the sweet range I'll put a circular barbell weight like 5 or 6 kg or 10lb or 14lbs(1 stone) on top of the speaker, with blutack.

initially I'll carefully (ie very hands-hovering!) experiment with balancing the speaker on a pencil or some kind of little rod, as a roller, halfway back, just to see how the weight distribution goes between the drivers at the front and the amps at the back.

Then with a bit of fiddling I ought to be able to position the weight to make the weight distribution even.

I might even be as organised as to do before/after rew measurements. we'll see...
Sounds like a plan, numbers are good
Old 18th December 2019
  #375
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Quote:
Originally Posted by mutetourettes View Post
happy to see this thread back in action - I'm going to get some sorbothanes for my APS Aeons (18kg / 40lbs)

I reckon I'll go for four 2"/30 duro each (11-16 lbs) for a range of 44-64lbs, sweetspot 54lbs/24kg

Then to make up the extra weight to be in the sweet range I'll put a circular barbell weight like 5 or 6 kg or 10lb or 14lbs(1 stone) on top of the speaker, with blutack.

initially I'll carefully (ie very hands-hovering!) experiment with balancing the speaker on a pencil or some kind of little rod, as a roller, halfway back, just to see how the weight distribution goes between the drivers at the front and the amps at the back.

Then with a bit of fiddling I ought to be able to position the weight to make the weight distribution even.

I might even be as organised as to do before/after rew measurements. we'll see...
well, I realised i had a pack of four of the 2"/30 pucks from a different project, so I did a quick and dirty before and after of these under one of my speakers - note I did NOT add any extra weight, so the sorbothane is quite underloaded here, and I cannot adjust the stands, so the speaker is approx 1cm higher, but in any case you can see how lots of ringing energy is being taken away from the lowmid and bass frequencies and shoved off below 20hz (speakers are pretty flat to 33hz). I wasn't expecting to see such a clear result for peanuts cash... :D hopefully even better if I add the right weight..

the graphs are the same axes etc:

without the sorbothane:
An inexpensive speaker tweak that works!-withoutsorbothane.jpg

with the sorbothane, inadequately loaded:
An inexpensive speaker tweak that works!-withsorbothane.jpg
Attached Thumbnails
An inexpensive speaker tweak that works!-withoutsorbothane.jpg   An inexpensive speaker tweak that works!-withsorbothane.jpg  
Old 19th December 2019
  #376
nms
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Quote:
Originally Posted by mutetourettes View Post
you can see how lots of ringing energy is being taken away from the lowmid and bass frequencies and shoved off below 20hz (speakers are pretty flat to 33hz). I wasn't expecting to see such a clear result for peanuts cash... :D hopefully even better if I add the right weight..
This looks unusual. If you're up for it, try repeating the process and post the second set of snapshots to see if they show the same thing.

What type of floor do you have? No other factors possible in the room such as a door open or closed?
Old 19th December 2019
  #377
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Quote:
Originally Posted by nms View Post
This looks unusual. If you're up for it, try repeating the process and post the second set of snapshots to see if they show the same thing.

What type of floor do you have? No other factors possible in the room such as a door open or closed?
floor is carpet on old stone on planet earth, as far as I'm aware conditions were identical between the two measurements, certainly no door difference etc, just the few minutes it took to put the sorbothane under, and the speaker is 1cm higher.

I'd not take these as a measurement of how my room is doing, as there's all manner of clutter around (including drums)! But the only difference between the two measurements was the sorbothane - the graphs are averaged from 8 sweeps each, mic approx 1m from a single speaker.

to be honest I didn't know if anything would show up as different, but I thought if people are hearing something improved it *might* show up in a measurement..

I don't know why decoupling the speaker from the stand would reduce 'ringing' of the mess of bass frequencies.

As you can see, initial frequency response is pretty identical.

There's clearly room stuff going on at 34 and 44hz, and also the APS Aeon ports seem to be resonant at 34hz

The stands are pretty crappy, so it may be that the sorbothane is radically changing their relationship with the speakers and how they react.

here's the stands back when i made them when they had K-Roks (and sorbothane hemispheres) on them:
DIY ultra cheap ~£30/€40 monitor stands from solid wood (Ikea)

I don't think another set of measurements will make much difference at this ppint, but I might do another set of before and after when I've got the proper extra weights on the speakers, and there's less crap in the room.

the measurements were at normal listening levels, I wonder if I did them really f**king loud it would be any different?
Old 19th December 2019
  #378
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Another product to consider for decoupling speakers is floor mount spring isolators like these-

https://www.supplyhouse.com/Vibratio...ators-23502000

The springs will have more deflection, which translates to greater isolation, and won't decompose over time. Generally they are going to work better in a situation where you can add some mass to the speakers or stand because these are made for heavier equipment.

The key part of the physics here is that this is based on the mass-spring equation-

http://farside.ph.utexas.edu/teachin...ves/node3.html

Single degree of freedom harmonic motion. This IS a tuned system, and for best results it's very important that the tuning frequency is infrasonic and 10hz or lower. You don't want the system to resonate in the audible band.

This is why you want to compress the springs, or sorbothane, to near their max deflection. Given the same newton force of the spring, the higher mass on the spring will result in a lower tuning frequency. This is also why solutions like tennis balls or random rubber aren't great. The newton force of the spring is unknown, and becomes difficult to impossible to tune it to the correct frequency.
Old 12th May 2020
  #379
Is this still considered a good idea?
If my speakers are 26lbs/12kg (APS klasik 2020) then should i get the hemispheres or the circular pad ones listed in the original post #1 ?
Keeping in mind my stands are fairly cheap: http://www.ultimatesupport.com/js-ms...ands-pair.html
Old 6th June 2020
  #380
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Picked up a 2 sets of 4 Sorbothane hemis 2.25 diameter, 1.125 height, 30 duro as recommened by Isolateit for my ATC SCM45s, which weigh 80lbs each. The hemis are rated at 18-26 per hemi so a total load of 72 - 104 lbs. Will be placing them on Sound Anchor ADJ-2 Stands, which will be on spikes and conecoasters as the stands will rest on hardwood and not carpet.

Before installing them, I just tried the speakers on my old ADJ-1 stands where I had 1.5 dia, 70 duro hemis, which are rated for the same weight...due to the distrbution of the weight of the speaker, and also being that the speaker has to hang over the front lid so it's not directly centered on the base, the front hemis are being compressed more than the rear, and the speaker is tilting downward slightly.

So before I install the 30 duro 2.25s on the ADJ-2 stands (larger bases so i'll get the base closer to centered, though still with a bit of the front jutting out more than the back, what's the best method to keep the speakers level?

Than you to anyone who can help figure this out, and also confirm I got the correct ones for the 45s.
Old 7th June 2020
  #381
Gear Addict
claimer: no expert here, but:
basically the front two pads probably will be carrying more load than they were designed to, due to the uneven mass distribution of the cabinet you are trying to isolate.

I had the same issue and ended up having three pads in the front, where the speaker chassis are mounted and only two in the back. This gave an even compression of the sorbothane pads, which is ultimately what you should be aiming for.

That said, you will need to purchase an extra pack of pads and also make sure you you stay within the specs of the specific pads you are using.
This will be an issue in your specific case, as you would need to add at least 10 lbs of mass to the speaker to be within spec if you decide to go that route.

Maybe someone else will chime in with a more elegant solution...
Old 7th June 2020
  #382
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Not a solution but CAREFULLY balancing a speaker (with an assistant) on a rod of some sort (like it was a see-saw) gradually moving the rod until the speaker is roughly balanced will then give you an idea of front-back weight distribution.. or maybe sit it on two sets of scales (front/back)?
Old 7th June 2020
  #383
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Seems complicated...hmmm...maybe i'll just try the speakers on the blue tack that come with the Sound Anchor ADJ-2s. They're such heavy stands, so I'm not sure if the sorbothane is really a huge improvement in my case. If it's worth it, i'll figure out a way...
Old 7th June 2020
  #384
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Here’s the product guide.

https://www.sorbothane.com/Data/Site...othane-SPG.pdf

Generally, it’s good to choose hemispheres (starting on page 8) rated for a quarter of the speaker weight and use a set of 4 per cabinet.
Old 7th June 2020
  #385
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Quote:
Originally Posted by jerry123 View Post
Here’s the product guide.

https://www.sorbothane.com/Data/Site...othane-SPG.pdf

Generally, it’s good to choose hemispheres (starting on page 8) rated for a quarter of the speaker weight and use a set of 4 per cabinet.
Yep but some speakers are front heavy with all the hefty magnets.. if you do two front two back, the front ones are overloaded so won’t work within spec (And the back underloaded so same) and the front ones will compress in time and the speaker may tip forward.. Even three front one back may be overcompensating... it may seem a little complicated to make sure each puck is properly loaded, but efficacy (and even safety) would suggest it’s worth it.
Old 7th June 2020
  #386
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I have 8 old sorbothane hemis from my previous speakers that are 1.5 dia, 70 duro - so while sorbothane.com recommended I use 2.25/30 duro for the ATCs, I'm thinking I can use the 70 duro 1.5s to experiment on a pair first, and figure out how to balance the weight...so I can try 3 in the front, 2 in the back, or different placements until the speaker is level...might that work?

The other option I saw were the iso acoustic pucks, which seem to be sorbothane based, but not a compression hemisphere...perhaps those will work without tilt? A lot more expensive, but whatever it takes to get it right...
Old 8th June 2020
  #387
Gear Addict
I would place four hemis in a rectangular layout and add a 5th one centered in the front. Then place a spirit level on the top of the speaker and start sliding the 5th one back until the speaker is level. Before doing this, make sure your speaker stand is level, of course

With my ATC 100 I ended up in a V-shaped layout for the 5th hemi if that makes any sense...
Old 8th June 2020
  #388
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Quote:
Originally Posted by Glamdring View Post
Hi guys, for ATC 45a which weigh 79.2 lbs per cabinet, am I correct with 6 x 2" Sorbothane hemispheres rated at 30 duro per speaker?
Hey @ Glamdring did you figure out the proper way to load ATC 45s on sorbothane, since the speakers are front heavy?
Old 8th June 2020
  #389
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Verified Member
Quote:
Originally Posted by mikoo69 View Post
Hey @ Glamdring did you figure out the proper way to load ATC 45s on sorbothane, since the speakers are front heavy?
Yo!

Yes - I have my ATC 45as on six pads per speaker. Three at the front and three at the back.

There is a very slight tilt to the front owing to the weight of the drivers, but it is only a few millimetres.

To be honest I didn't really consider it that much of an issue - but welcome any futher education on the subject and understand the loading now is not quite correct...
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