Are Auralex Mopads just thick packing foam?

[pitchfork]

Ha! Love the foot pads. Bet they're made of something similar to Sorbothane. I'll have to check them out.

However..I'm ummm, can someone explain exactly WHAT he is trying to decouple the monitors FROM? And why? He didn't bother to explain.

[jhbrandt]

Fitz, old boy!

Decouple them from the room structure.

If not, you can experience early, early sound. This is sound transmitted via the structure of the room, floor, ceiling, etc., and can arrive at the listener BEFORE the sound in the air from the speakers. But you know this already, right?

- hey, stay in touch, man. send me an email.

Cheers,
John

[pitchfork]

Hmmm, just did a search on the Heel Cushion material. Although I didn't find out what this "gel" material is yet, I DID find another product made by Dr. Sholls, that described the base material as PORON. Seems interesting, although I don't think you'll find it at Walmart.

PORON Urethanes

But you CAN find it at McMaster-Carr-not to mention a gazillion other products.
McMaster-Carr

Amazing what you find on the net. I got the link from a DIY edrum thread.

They use PORON for piezo trigger pads.
Foam Castles

I've used McMaster-Carr for over 20 years. Their product list is astounding.
You can find virtually anything you need.

Ok, now to find the Heel Cushion material. God I love the net.

[pitchfork]

Fitz, old boy!

Decouple them from the room structure.

Hahahahaha...John, it was a rhetorical question. I KNEW, but figured I'd let a PRO define it ..you know..for those that don't understand the reasoning.

- hey, stay in touch, man. send me an email.

Cool. Will do...er..I'll have to PM ya though. Don't have your email addy. Maybe Facebook?
rick

PS, I do have question though John.

This is sound transmitted via the structure of the room, floor, ceiling, etc., and can arrive at the listener BEFORE the sound in the air from the speakers. But you know this already, right?

Which listener?(tongue in cheek)

Seriously though....two room studios notwithstanding, for a typical one room studio with engineer...sitting 4-8 feet from a monitor..is the time difference detectable by the brain... IE...that theory(can't remember) defining sounds arriving within 20ms of the direct sound... are assimilated as one? so to speak. In other words...does it really matter? And just how would this early early sound, transmit to your ears? Through you feet?

Even if it does...are there any tests confirming any aberrational effect in ones engineering judgements? Just trying to establish whether or not stuff like this really is a concern...or a brain fart. I mean, for 20 years I've seen the hoops people jump through to achieve solution X when there may not be a qualitative reason to do it in the first place. Just asking John. Thanks

[pitchfork]

Decouple them from the room structure.

One more thing John. The author doesn't say what these monitors are sitting on..ie..Stands or Console?

If stands are being used, correct me if I'm wrong, but doesn't the mass of the stand have something to do with it? From various sources over the years, I was under the assumption the stands need mass..which with monitor weight added, is the actual mass that needs decoupling from the floor via what ever device..ie..Sorbothane pads or whatever. ...no? If not..please explain the concept. I'll add it to my list of concepts to explore for the next 20 years.

[darrella]

[darrella]

John, when you say durometer, are you speaking of a tire-type durometer placed against the compressed/uncompressed material?

[jhbrandt]

Originally Posted by pitchfork

....two room studios notwithstanding, for a typical one room studio with engineer...sitting 4-8 feet from a monitor..is the time difference detectable by the brain... IE...that theory(can't remember) defining sounds arriving within 20ms of the direct sound... are assimilated as one? so to speak. In other words...does it really matter? And just how would this early early sound, transmit to your ears? Through you feet?

Even if it does...are there any tests confirming any aberrational effect in ones engineering judgements? Just trying to establish whether or not stuff like this really is a concern...or a brain fart. I mean, for 20 years I've seen the hoops people jump through to achieve solution X when there may not be a qualitative reason to do it in the first place. Just asking John. Thanks

Yes, we do tests like this all the time and see it on the ETC. The 'early-early' sound is most noticeable when flush mount mains are improperly done resulting in the coupling of the speaker cabinet to the room structure. It is often heard as a pre-echo overhead, & I have heard it come from the console and the side wall area as well. Yes, it is noticeable. As with any reflection or out-of-phase/sync signal mixing with the source, it can/will be the cause of image-smearing artifacts or comb filtering.

Originally Posted by pitchfork

One more thing John. The author doesn't say what these monitors are sitting on..ie..Stands or Console?

If stands are being used, correct me if I'm wrong, but doesn't the mass of the stand have something to do with it? From various sources over the years, I was under the assumption the stands need mass..which with monitor weight added, is the actual mass that needs decoupling from the floor via what ever device..ie..Sorbothane pads or whatever. ...no? If not..please explain the concept. I'll add it to my list of concepts to explore for the next 20 years.

The mass of the stand acts as a reference 'base'. This base should be 'like-a-rock', solid, and non-moving to provide substance for the woofer to push from. The speaker should be decoupled from the stand with the appropriate 'spring' to isolate the speaker from the stand and therefore the room structure. Doing so will improve perceived transient response, clarity, detail, and focus. (audiophile terms)

Originally Posted by darrella

John, when you say durometer, are you speaking of a tire-type durometer placed against the compressed/uncompressed material?

Correctamundo! But this is not something that you should need to do. The maker of the product should have this specified in their product data.

Cheers,
John

[musikmaschine]

I saw this thread so i didn't want to start another as it's discussing sorbothane. I'm looking at Sorbothane to isolate some small passive speakers from a monitor shelf.

The shelf isn't vibrating too much but i feel that the low end energy is being absorbed so i was going to buy the insoles and try cutting a few pieces out; is this the best thing to do, will it be effective or should i just go straight for the hemispheres or precut squares?

I also have hs80s on stands with mopads so would sorbothane sheets be good? The stands are not solid and do move so again i think a lot of the low end energy is being lost through the wobbly bases which i will replace with better stands at some point. Thanks.

[AreYouHuman]

Originally Posted by jhbrandt

The mass of the stand acts as a reference 'base'. This base should be 'like-a-rock', solid, and non-moving to provide substance for the woofer to push from. The speaker should be decoupled from the stand with the appropriate 'spring' to isolate the speaker from the stand and therefore the room structure. Doing so will improve perceived transient response, clarity, detail, and focus. (audiophile terms)

John I'm really thankful that you share you knowledge here. This is something I ask myself since ages.

But let me ask a question. When we decouple the speaker from the stand, the mass of the stand can't act as counterweight, because it has no solid connection. Brief: when the speaker "wobbles" a bit on the "spring", shouldn't the impulse response be worse? Therefore it should be better to couple the speaker to a mass and decouple that mass+speaker from the room. Feel free to correct me if I'm wrong!

SPEAKER
MASS
SPRING
MASS
MASS

VS.

SPEAKER
SPRING
MASS
MASS
MASS

If I'm right, any idea how big the coupled mass to the speaker has to be to act as a counterweight against the woofer?

Best Regards!

[OpusOfTrolls]

Obviously, more mass above the spring will result in a tighter excursion. But what's more important is mass overall. Then the spring must be loaded properly to attain a natural frequency over an octave below the f3 of the speakers. Do not neglect to add a bond between speaker and stand, or else they might just fall off.

[stevegalante]

In reference to Sorbothane Hemispheres 2" again, I contacted a reseller, and here's what they told me :
"I stopped carrying them because they warp a lot over time, biggest I have now is 1.25in or 2.25in discs."
Did anyone experienced this too ?

[binman_uk]

Hi guys,

I'm interested in getting some sorbothane - could anyone help me work out what size/thickness I'd need put under some Alesis M1 Mk2 speakers?

Dimensions: 381 x 216 x 248mm. Weight: 9kg each.

Was thinking of these?

http://www.ebay.co.uk/itm/261042062824

Any help much appreciated.

Cheers.

[binman_uk]

anyone ?

[stevegalante]

Originally Posted by stevegalante

In reference to Sorbothane Hemispheres 2" again, I contacted a reseller, and here's what they told me :
"I stopped carrying them because they warp a lot over time, biggest I have now is 1.25in or 2.25in discs."
Did anyone experienced this too ?

Exactly, anyone ?

[binman_uk]

No matter anyways. Got some off ebay. 30mm width domes, 15mm high.
Should do the job.