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Discussion Starter · #1 ·
Hi,


I called Pac-International the Makers of the RSIC-1 clips and Spoke to Mike Gernhart and this is what I Learned Regarding Placement of RSIC-1 clips vs performance.


I'm posting this info here because maybe someone else may need to know this info one day Like I did.

My First Question was...

When Framing a 2x4 Studded room out, Is there any special clips that need to be used to join the studded walls together?

Mike Gernhart's Reply was

"No. Just Frame out the Room like you normally would and think of these RSIC-1 clips as a patch and repair kit that fixes the wall after Its up."

My Next Question was...

Will Accoustics Benefit if I build deeper walls, like use 2"x8"s instead of 2"x4"s for framing with RSIC-1 Clips?

Mike Gernhart's Reply was

"The Difference is a .1 to .2 Difference which is basically No difference to the Human ear because the human ear can only hear a .5 difference and above."

My Next Question was...

Will using Stagger Studded Walls increase performance with RSIC-1 Clips?

Mike Gernhart's Reply was

"No."

My Next Question was...

Will the use of RSIC Clips on both Sides of a freestanding 2"x4" studded wall increase performance?

Mike Gernhart's Reply was

"No. It will only make it worst because both walls will then be moving."

My Next Question was...

If You have Concrete walls, is It better to frame out a new wood studded wall in front of the concrete wall and and use RSIC-1 clips on the new wood studded wall. Or, attach the RSIC-1 Clips directly to the concrete Walls?

Mike Gernhart's Reply was

"If You don't need the extra space inside the walls for work boxes, outlets, etc. then attaching the RSIC-1 Clips directly to the Concrete Walls performs just as well."

My Last Question was...

If You have a concrete Ceiling, is it better to frame the ceiling out first before using the RSIC-1 clips or just attach the RSIC-1 clips directly to the concrete ceiling?

Mike Gernhart's Reply was

"There hasn't been any recorded differences between Framing out a concrete ceiling up to 30" deep opposed to attaching RSIC-1 clips directly to a concrete ceiling."


I also found the RSIC-1 Clips for $4.40 each when you buy 100 or more at...
http://www.professionalacousticsco.c...ping_cart.html


Ruben
 

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My thoughts on his answers are .... well puzzled to say the least.


Frankly I would put more weight from the opinion of Brian (sound engineer) or Dennis (HT engineer) for the "real world" effect trying to soundproof and decouple a room. Not that this fella doesn't know his product, but I would like to know how many test out in the field he has performed and has he ever installed them himself.


As far as the walls comment. Why would someone purposely couple their walls to the existing framing, only to HAVE TO fix this problem by using RSIC-1. A decoupled wall and /or a decoupled staggered stud wall will work very well. No need for RSIC on the walls, just on the joist above for the HT ceiling.


In the CATV business, we have a lot of glorified experts from the training side who have never worked hands on with the equipment. I would respect the opinion of a field technician over the trainer anyday.


Scott
 

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guys, i have been avoiding posting this week as i'm horrendously busy and might not be able to reply should someone ask me to elaborate... but i'm going to make a comment on this thread, i hope i make it clear enough to make sense without re-explaining myself

Quote:
Originally Posted by SandmanX
Hi,


I called Pac-International the Makers of the RSIC-1 clips and Spoke to Mike Gernhart and this is what I Learned Regarding Placement of RSIC-1 clips vs performance.


I'm posting this info here because maybe someone else may need to know this info one day Like I did.


My Next Question was...

Will Accoustics Benefit if I build deeper walls, like use 2"x8"s instead of 2"x4"s for framing with RSIC-1 Clips?

Mike Gernhart's Reply was

"The Difference is a .1 to .2 Difference which is basically No difference to the Human ear because the human ear can only hear a .5 difference and above."




the answer to this is YES. the reason is that doubling the depth of the air cavity will (maybe greatly) lower the low-frequency mass-spring resonance and (maybe greatly) lower the frequency at which the clip become effective decouplers.


this is a great product, it makes a great wall on 2x4's, i absolutely promise you that low-freq performance will be notably improved on 2x8's or 2x10's etc.. these are the immutable laws of physics, and i'm willing to wager the cost of the tests on proving it at a 3rd party lab if anyone is willing to be a taker.

Quote:
My Next Question was...

Will using Stagger Studded Walls increase performance with RSIC-1 Clips?

Mike Gernhart's Reply was

"No."
and he's right for mid/high. the RSIC clips are a superb decoupler, and the extra decoupling from staggered studs is inconsequential.


BUT THE STAGGERED WALL IS DEEPER = LOWER MASS-SPRING RESONANCE = LOWER FREQUENCY OF EFFECTIVE DECOUPLING. this is plainly visible in myriad tests with resilient channel on stagg studs -vs- RC on 2x4's. the RSIC clips will follow suit.

Quote:
My Next Question was...

Will the use of RSIC Clips on both Sides of a freestanding 2"x4" studded wall increase performance?

Mike Gernhart's Reply was

"No. It will only make it worst because both walls will then be moving."
there is data to support his assertion with resilient channel - adding channel to both sides causes even more sub-region performance loss than channel one side, although it's not likely that STC would go down, and it might go up. with RC, STC rises when adding channel o the second side...


this is no resilient channel, this is a much nicer product, and his advice is 100% solid. this was an agreement, just a chatty one.

Quote:
My Next Question was...

If You have Concrete walls, is It better to frame out a new wood studded wall in front of the concrete wall and and use RSIC-1 clips on the new wood studded wall. Or, attach the RSIC-1 Clips directly to the concrete Walls?

Mike Gernhart's Reply was

"If You don't need the extra space inside the walls for work boxes, outlets, etc. then attaching the RSIC-1 Clips directly to the Concrete Walls performs just as well."

My Last Question was...

If You have a concrete Ceiling, is it better to frame the ceiling out first before using the RSIC-1 clips or just attach the RSIC-1 clips directly to the concrete ceiling?

Mike Gernhart's Reply was

"There hasn't been any recorded differences between Framing out a concrete ceiling up to 30" deep opposed to attaching RSIC-1 clips directly to a concrete ceiling."
i again will wager the cost of the tests, out of my personal pocket, if i can't demonstrate demonstrative low-frequency gains (sub-region) due to increasing the size of the cavity. most tests are 100-5000hz, it might not show up there, or it might, often people just look at STC, and STC may well not improve.


the only cop-out for this wager that i will request is the right to have proof that the facility is not flanked-out.



mass-spring-mass resonance will lower, low frequency performance will improve.



i really dig those clips, they really ARE better than RC. and i think i understand where Mr. Gernhart is coming from, and his points are not invalid.


but i absolutely promise you that depth is a good thing for low-freq isolation. heck, that's a phenomenal benefit of the clips themselves, an extra 1.625" of depth.





now, on a rigidly coupled wall, like 2x4 -vs- 2x6 -vs- 2x10 etc., adding depth doesn't help you much at all.


a GG wall will benefit a bit ore than a normal wall from this extra depth, for what that's worth, but an RSIC clip or spring hanger or RC or double studs, a SIGNIFICANT increase in depth (like 50% or something) will always increase low-freq performance.


THIS POST IS NOT MEANT TO SAY THAT YOU NEED MORE DEPTH, JUST OBSERVING.


g'night and i really hope this post makes enough sense to not cause confusion if i can't reply to it soon.
 

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the point where additional air will not matter is that point where the spring force of the clip itself is >> than the spring force of the air in the cavity.


and not an inch sooner


:)


darn, darn, darn that STC system. [email protected]^$&@$&*#%*#%^
 

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....also, as a point of reference, Gernhart comes from the STC world where below the 1/3rd octave centered at 125Hz "don't mean nutting". His experience base is completely within the STC range and our concern (and thanks to Brian for his research and product) goes much lower in frequency than that.
 

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Not meaning to hijack the thread, but a somewhat related question...


If I have a room that is already finished (2x4 exterior walls with 1/2" dywall on interior, plywood sheathing and hardi-plank siding on exterior, with standard fiberglass batt insulation), is it worth the effort (from a sound isolation standpoint) to rip out the drywall and re-frame to create a staggered stud wall, using RSIC-1 and double drywall with green glue, or will I get similar sound isolation by using RSIC-1 RETRO clips on the existing drywall (in line with the studs, of course), followed by two layers of drywall with green glue?


The second approach would yield a void between the back of the new drwall and the face of the existing drywall. I would likely fill this void with a layer of mineral wool insulation. It has the obvious appeal of not needing to rip up a bunch of existing drywall and creating a big mess...


Thanks for any insight about this!


Dwight
 

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Quote:
Originally Posted by dwightrahl
Not meaning to hijack the thread, but a somewhat related question...


or will I get similar sound isolation by using RSIC-1 RETRO clips on the existing drywall (in line with the studs, of course), followed by two layers of drywall with green glue?
You just did.


No. This willl form a triple leaf.


Andre
 

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Discussion Starter · #8 ·
Quote:
Originally Posted by dwightrahl
Not meaning to hijack the thread, but a somewhat related question...


If I have a room that is already finished (2x4 exterior walls with 1/2" dywall on interior, plywood sheathing and hardi-plank siding on exterior, with standard fiberglass batt insulation), is it worth the effort (from a sound isolation standpoint) to rip out the drywall and re-frame to create a staggered stud wall, using RSIC-1 and double drywall with green glue, or will I get similar sound isolation by using RSIC-1 RETRO clips on the existing drywall (in line with the studs, of course), followed by two layers of drywall with green glue?


The second approach would yield a void between the back of the new drwall and the face of the existing drywall. I would likely fill this void with a layer of mineral wool insulation. It has the obvious appeal of not needing to rip up a bunch of existing drywall and creating a big mess...


Thanks for any insight about this!


Dwight
I Beleive adding RSIC-1 Clips to your existing Walls right on top off your existsing sheetrock and then adding another 2 layers on top of the RSIC Clips would be even more effective.
 

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Ruben:


Did you miss my post immediately before yours? That will create a triple leaf whic is bad for isloation.


Andre
 

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I must say, the folks at Pac-Intl are very good about providing quick answers to questions you give them on their website. I asked for some information regarding the RSIC-1 Retro product with respect to triple-leaf issues (and I asked about the use of staggered studs), and within about 2 hours of sending the question, I got the following reply:

You are right, a triple layer system is not good. However, the RSIC product delivers such extreme high noise reduction to most assembly into which it is introduced the negative impact of the extra layer in the middle of an assembly (such as the RSIC-1 Retro) is less than the positive impact of adding the RSIC-1 and the extra layer of gypsum board thus the NET gain is approximately 10 to 12 STC or about 100 to 120% change in a the amplitude of noise transferring through the wall.


Yes you would receive even a Higher Net gain in noises reduction (approximately 200%) by removing the existing layer of gypsum board and installing the RSIC-1 directly to the framing members. One additional advantage of removing the existing gypsum board is the wall width would be thinner. You would have a chance to increase the insulation in the wall cavity to the maximum the Newly created air space can accommodate.


As to the Staggered stud idea. The fact is the structure born noise transmission is the path of least resistance for noise transmission. In the staggered stud design there is a common top and bottom plate so the noise simply follows the structure born path to radiate from stud to plate to stud the net acoustical improvement would be an improvement but not proportionate to the expense and the usable floor space lost the stagger stud assembly. The exception would be if you used the RSIC low profile wall and the RSIC-1. Here is a hyperlink to the RSIC low profile wall design for your convenience: http://www.pac-intl.com/decoupled_lp_wall_system.html


If wall width (lost floor space) is a serious consideration, as an alternative to the stagger stud wall you may want to consider a single stud wall and the RSIC-1 with additional layers of gypsum board for improved acoustical performance.


Last you may want to consider the application of Mass Loaded Vinyl attached directly to the framing members prior to the installation of the RSIC-1 product. When used as a limp mass the Mass loaded vinyl can help to close the 2500 hertz dip caused by the natural frequency of 5/8" gypsum board. Some reseller of MLV charge excessively for MLV. I do not know whom is the best priced reseller of MLV, so please use caution when shopping for MLV IF you choose to add MLV to the wall design.


Gotta love it when questions get answered quickly.


In reading the above, does anyone disagree with the suggestions?


Thanks,


Dwight
 

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Quote:
In reading the above, does anyone disagree with the suggestions?
REad teh percenatges about improvment of triple kleafing with RSIC. The imp0ication is that you can the same with just doubling the :)


If you are serious about it avoild triple leafs. OTherwise you are wasting your momey.


Andre
 

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Quote:
Originally Posted by dwightrahl
I must say, the folks at Pac-Intl are very good about providing quick answers to questions you give them on their website. I asked for some information regarding the RSIC-1 Retro product with respect to triple-leaf issues (and I asked about the use of staggered studs), and within about 2 hours of sending the question, I got the following reply:

You are right, a triple layer system is not good. However, the RSIC product delivers such extreme high noise reduction to most assembly into which it is introduced the negative impact of the extra layer in the middle of an assembly (such as the RSIC-1 Retro) is less than the positive impact of adding the RSIC-1 and the extra layer of gypsum board thus the NET gain is approximately 10 to 12 STC or about 100 to 120% change in a the amplitude of noise transferring through the wall.
very small air space will lead to problems below the STC range. please take out the existing drywall and reap thefull potential of teh RSIC product.
Quote:
Yes you would receive even a Higher Net gain in noises reduction (approximately 200%) by removing the existing layer of gypsum board and installing the RSIC-1 directly to the framing members. One additional advantage of removing the existing gypsum board is the wall width would be thinner. You would have a chance to increase the insulation in the wall cavity to the maximum the Newly created air space can accommodate.

Quote:
As to the Staggered stud idea. The fact is the structure born noise transmission is the path of least resistance for noise transmission. In the staggered stud design there is a common top and bottom plate so the noise simply follows the structure born path to radiate from stud to plate to stud the net acoustical improvement would be an improvement but not proportionate to the expense and the usable floor space lost the stagger stud assembly. The exception would be if you used the RSIC low profile wall and the RSIC-1. Here is a hyperlink to the RSIC low profile wall design for your convenience: http://www.pac-intl.com/decoupled_lp_wall_system.html
you don't need stagg studs with RSIC, the clips are more effective decouplers than the staggered studs, BUT the extra air space is good...
Quote:
If wall width (lost floor space) is a serious consideration, as an alternative to the stagger stud wall you may want to consider a single stud wall and the RSIC-1 with additional layers of gypsum board for improved acoustical performance.


Last you may want to consider the application of Mass Loaded Vinyl attached directly to the framing members prior to the installation of the RSIC-1 product. When used as a limp mass the Mass loaded vinyl can help to close the 2500 hertz dip caused by the natural frequency of 5/8" gypsum board. Some reseller of MLV charge excessively for MLV. I do not know whom is the best priced reseller of MLV, so please use caution when shopping for MLV IF you choose to add MLV to the wall design.
i urge you to not put anything behind the clips. creates a small air space. there is no existing test data for MLV taken by any maker and published (to the best of my kohwledge). a far, far cheaper way to control the coincidence dip that is very well proven to eliminate the dip in lab tests is a damping material.


or spend the money on more clips and do a triple layer of drywall. via my most solemn vow i promise these are better ideas.
 

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Hi Brian,


Thanks so much for again taking the time to answer questions about sound isolation.


I will be removing the existing drywall in the room and installing RSIC-1 clips on the existing 2x4 walls. I'll fill the additional space between the stud face and the back of the first layer of drywall with insulation, and apply 2 layers of drywall with green glue in between.


I'll also do a similar treatment to the ceiling, which is starting life as a cathedral ceiling. I'll hang a proper two-layer drwall ceiling from new ceiling joists that I'll install to provide a flat ceiling.


Thanks again,


Dwight
 
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