No "Room Correction" Topic option. Why?

Good question about matching elastomeric to drywall, Tomic. Another reason to choose something engineered over something contrapted. I use elastomeric to join things that can’t be bought as an engineered unit - like drywall to stud.

Nice thread, reasonably sane by Gon standards....

One key question to ask is does brand X elastomeric between two sheets of Y constitute a constrained layer - converting some motion into heat ?

Rettinger covers all the ratios.... including the nasty but popular one...

and of course there is a nice page on staggered wall construction, I paid $10 for a deactivated Library copy....

I did something very acoustically low tech this week. It could be a smart or a stupid idea. It was done for my back health and to also get away from my desktop computer while I listen to headphone music. So less A’gon posts by me.

I got a big bean bag that I put up in the worst acoustic location of my small room. Tomorrow, when I get delivery of a 2 channel speaker amp I will be able to test out how great an ideal this was. The room was pretty good before and the bean bag is super comfortable. I may have a conflict.

@yyzsantabarbara 

I note that your article references the Salford simulations. Nice to have company!

People are missing the point of measurement and software and science and listening, they are not mutually exclusive, rarely is one sufficient.

studio six Digital provides a low / no Cost toolbox... start there

avs, felt is not a super broad band absorber But you do see it deployed on a variety of speakers - typically the mid and tweeter. 

Yyz that’s the company I mentioned, very effective 

They acoustic engineer who will be helping me next with my room + speakers told me to consider the following.

PS. Heavy velour drapes like https://www.acoustic-curtains.com/curtains/acoustic-curtains/ work wonders.

I initially worked with GIK Acoustics to treat the room and they were amazing. I am trying something a little more ambitions next and will use DRC for that.

https://audiophilestyle.com/ca/bits-and-bytes/what-is-accurate-sound-r923/

@tomic601 ....Thanks for that correction re sorbothane.
I'd love to apply the stuff liberally, but the $ involved vs. the sizes I'd like to apply kinda make it unobtainium on a practical level.

If I won a Powerball lottery however, that, and a lot of other things would obviously change in a rather radical fashion. *evil G*

'Scuse the late response...spent the weekend driving 380ish miles....twice.  'Mental road rash' takes a day to recoup from.... ;)

Personally, I've been curious about the use of sheet felt (1/2" thick or greater) as an acoustic accoutrement...any thoughts, yours or the collective?

@Chorus - You have 240VAC into your room right?  If you don’t mind, how many conductors are there (in conduit?) and what color are the insulation of the conductors please?

I have been following acoustic fields lately.

So much good information coming from so many sources - thanks for this thread, brilliant!

I guess i was lucky or more diligent in my working experiments....

My speakers sound marvellously well in a bad location and in a bad room...

Active device controls and not only passive materials are the key....You can use a computer to compute the nodes where to put the reflective and absorbant materials, but we must use our ears with the powerful active devices to decide how to connect them and with what and where to put them ( different resonators connected to Schumann generators).

Not only that but my 7 inches driver gives so much clear bass that i listen to with my body then a sub was really without interest... I disconnect the one i own, and i purchase it before my experiments....I listen mainly acoustic music....Cello, organ,piano and human voices.... No need of speakers management controls, perhaps to improve my results a bit for sure , but not more....I want to try the speaker mangement controls understand me, but my active room controls are so good that it will be ONLY to optimize what is already more than good...

No sibilant, clear bass, and imaging and decoupling music sound from the speakers.... That are my results....

Cost : peanuts.....



I will not annoy the reader in reexplaining what i said today in an another thread...i already said too much....

:)

« Why do you trust your ears more than a computer? Because we make love together in the old way» - Groucho Marx

The way to build a quiet wall is not with two layers of sheet rock. You build quiet walls. These are usually made with 2 X 6 sills and staggered 2 X 4 studs each opposing wall gets it's own studs so there is no direct mechanical contact between either side of the wall. Works great. We build such a wall between the master bedroom and my daughter's bedroom as our bed is right up against the wall. You can jump up and down on that bed till the cows come home and you can not hear a darn thing on the other side of that wall:)))
As for my music room? The system rarely goes below 80 dB and you are never going to hear the AC over that. The only thing I care about are rattles. I HATE RATTLES. So, bring on the construction adhesive and silicone.

I suppose it is time for me to rant.
I think egenmedia is right. The dimensions and design of the room are most important when it comes to bass. I think length vs width should be at least 2 to 1 and width vs height again 2 to one or better. Leave the back wall open. In my house the back wall opens to the kitchen and a hallway. The kitchen then opens to the dinning room. The nearest full wall is 80 feet from the Hi Fi. All the walls including the interior ones have 2 X 6 studs covered in blue board and two coat plaster. Construction glue was used under the blue board but I can not remember what kind. That was almost 30 years ago. The Quietrock does look like an interesting product. If I were ever to build another house I would give it a try. With my system set up like it is there is no nodal behavior that you can consistently measure but there is a lot more to it than the room. One of the best ways to deal with room acoustics is to have speakers that do not throw energy all over the place. Horns and dipole linear arrays have the most controlled dispersion. I personally prefer dipole linear arrays for everything above 125 Hz. They throw very little energy to the sides, up or down and what bounces off the front wall is easily controlled with absorption devices. In order for an array to be linear down to 125 Hz it has to be taller than 10 feet or butte right up to the floor and ceiling. So, in an 8 foot tall room you need 8 foot tall dipoles. ESLs are perfect in this role. The same applies for bass except the array needs to be on the floor right up against the wall into the corners and each driver must be no more than 5 feet away from the next. 
I have read many assumptions about "room control" from people who have little extended experience with it or really understand what it is all about. Room control is really not room control. You can not change a room's modal behavior by monkeying around with frequency response. It is digital speaker control. The benefits are that you can digitally equalize your left and right speakers so that they have dead flat and exactly the same response curves as a starting point. Then you do the same for your subwoofers as well as supply the crossover and sinc them in time and phase with your satellites. In doing this the computer is taking into account any frequency response interaction between the speaker and the room in their individual location. No two speakers are identical. No two speakers occupy the same location in a room. Any frequency response differences between channels will muddy your imaging. Once everything is flat you can institute changes that you find beneficial. At normal listening levels I like the treble rolled off so that it is down 6 dB at 20 kHz.
I find flat is too bright. All the processing is done 48/192 and essentially distortionless particularly in reference to anything you might do in the analog domain. But, you can not fix a bad room with digital speaker control. You can manage it to a degree with the right speakers and acoustic treatment but it is always going to be a bad room. 
It is absolutely not true that the effect of speaker control can only be advantageous at the listening position and egregious everywhere else.
The benefits are heard throughout the room. Many current systems take measurements at several places in the room. 
There are many other advantages of digital system management and speaker control. 
Having lived with it for 20 years. I will never be satisfied without this capability. I can instantly remove the sibilance from any recording, bring the treble out in a dull recording and neutralize fat bass. I have programmed dynamic loudness compensation. The tonal balance remains the same regardless of volume. You can make your system sound however you want. You can not get the absolute best bass without it but you still have to have the right speakers and room to get there. You can not get the best imaging without it but you still have to have the right speakers and room. If you have the right speakers and room and are willing to put in the effort to learn how to manage this (steep learning curve) you can make some very appreciable improvements in your system's performance. That includes the analog side of things as well.
If you want to be a digital phoebe and shoot yourself in the foot that is fine also but don't dis it until you have spent at least a year with it. If you are making negative comments on a 15 minute exposure you are doing yourself and others a disservice. 

Meant to say:   "Turn the room upside down and fill it with water, then find the leaks".  

I happen to be friendly with Scott Hull, the owner of Masterdisk, grammy winner, chief mastering engineer.  At some point he will be coming to my
house for final tweaking (and then I'll tweak it to where I like it). I have listened to some master tapes sitting in the "captain's" chair at the console. Very interesting.  Anyway, one of his first thoughts as I picked his brain for a while was "Turn the room upside and fill it with water, then find the leaks".  Thought experiment obviously, but it stuck with me.

@invalid Do you have the brand name of the carpet glue, just curious.

I had an unrelated call with Richard Vandersteen yesterday and we got to talking about the room - talked about a Mutual friend of Our who owns an audiophile record company - super high grade reissues - his quality evaluation/ listening room also included The above in the thread  mentioned golden ratio, double layers, air gaps, etc we have been talking about but also S ducting on the air conditioning/ heat ducts as well as the return line.
free pro tip

I used two layers of 5/8" drywall on the room I built, but I couldn't afford green glue so I used an elastomeric carpet glue at about one tenth the price. The green glue might be better, but this carpet glue worked really good, I still have a scrap piece of drywall with the stuff on it and it is still soft and pliable. If you go with two layers of drywall don't get the newer light weight 5/8" drywall it doesn't have the density of the heavy 5/8". My room is so quiet that I noticed I have a slight case of tinnitus that I never noticed before.

Don't forget the cost of labour to put up two layers of drywall and slather with green glue, instead of just one layer. If you're not doing it all yourself, that is.

Good luck!

Terry,  My understanding is that a double layer of 5/8" drywall with Green Glue in between does not vibrate at all.  That's not to say that Quietrock is not better, probably is, but I do have a budget.  As I have said I will be looking into both. BTW the room didn't sound bad with the old sheet rock. Thanks for the input. I'll let you know how it goes.
Regards, barts
 

Barts, it's actually a whole lot more than soundproofing. The thing is to make the walls rigid, so that they don't flex in response to sound energy, especially sound from the speakers.

If the walls do flex, they act like exceedingly low grade woofers - woofers made of drywall, responding out of phase. Hence Quietrock 545 with embedded sheet steel.

This may be of use.

https://www.acousticfields.com/ten-guidelines-for-room-acoustic-treatment/

i prefer natural absorption w rugs and furniture, hiding acoustic absorbers behind artwork, acoustical curtains if absolutely necessary, plants as diffusers and RPG wood diffusers.

handymann

One can split a 220VAC line and both are already on the same side of the buss, however if you have two high current monoblocks, the ground or “common” will not be able to carry the amperage that one will need for each amp.

If we are talking about residential use in the US, this does not make sense. A 240VAC line would consist of a pair of 120VAC lines each fed from a different bus. There’d be no way to have them on the same leg. NEC allows the 240VAC line to be split into two 120VAC lines with a shared neutral. Each 120VAC line must have its own appropriately sized breaker, and the breakers must be tied together so that both trip simultaneously. You would need to check with your local inspector to determine if such connections meet local code.

Thanks to all for the discussion/ideas of soundproofing, regards to chorus who I hope doesn't think I meant to hijack his thread.

@tomic601 Totally agree with you that I'm looking for the lowest "noise floor" I can achieve in my music room, although not at the expense of making the room dead.

@terry9  Thanks for the leads to other products I will consider.

@eganmedia  I have to live with with the room I have,  I consider myself fortunate to have a room I can do whatever I want to.

I have not heard anyone mention that all this soundproofing made the room dead.  So, my original fear of over doing it to achieve the lowest noise floor seems to stand on it own and doesn't make the room dead, just quiet from invasive noise.
Regards, barts

One can split a 220VAC line and both are already on the same side of the buss, however if you have two high current monoblocks, the ground or “common” will not be able to carry the amperage that one will need for each amp.  If you have a stereo amp and simply want to connect your low power equipment to the other line, it will work.  If you have a 40 amp breaker, you’re in luck.  Codes however, may be a problem.

My Dad was an electrical contractor.  I split my 220 dryer outlet  The breakers are easy to change out, and don't really require that you turn off the power, unless you are a klutz. A duplex recepticle can have both 110 outlets. 

Acoustical embedding are the more important..... More than mechanical and electrical one in power to deliver S.Q.

Passive materials treatment are only HALF of the story....

Active device controls can make your audio system to be freed from the limitations of the room...(i mean non electronical device by the way)

Almost nobody speak about that....Except some sellers of very costly device....It is not necessary to buy one if you know what to do..... Cost: peanuts.....

"Generic" designed speakers dont have soul and body, without a "specific" room designed by you to be his working organ synchronizing with your ears....

:)

The editor of Stereophile had an interesting editorial regarding rooms that I totally agree with...a room often adds a sense of reality that renders digital "correction" unnecessary. Digital "nannies" might be useful if your room has no furniture and glass ceilings or you live in a dumpster, but, for example, digital bass correction puts in a slight delay and adds phase issues to a signal that isn't worth it. For my room, furnishings are all the correction I need...for you, buy stacks of bass traps and heavy curtains and you can reach for a sound devoid of life.

#millercarbon knows everything. He loves to show off a system he claims is his.

Chorus, I suggest that you also consider the lights themselves. LED's and fluorescents tend to create electrical noise which can get back into your equipment - certainly through the line, but also perhaps through EM radiation.

Does not apply to strips of bare LEDs, and maybe some other LED fixtures.

I used 12V quartz track lighting throughout, powered by 20 little toroidal transformers mounted outside the room (in case they hummed). The electrician was great and did all the hard work, leaving me to sort out logic and connections. 

Agree, IF luxury get the room dimensions correct - golden ratio , Fibbonachi sequence, yes!Then room noise floor
The stereo illusion is fragile at best, I myself mostly a seated listener don’t mind 11 bands of analog EQ below 120 hz w typical room node centers and cut 2x boost.
but of course there are other ways
i find real living spaces often far exceed over treated dedicated rooms, not always but often.
best to all

Tomic, you might like to know that both M1 and BuildSecure are low-odour, low-VOC, non-toxic substances. Unlike some other construction glues I could name. And elastomeric is only common sense in an active earthquake zone.

Egan, you are absolutely right. The first thing one notices upon entering my music room is the quality of the silence. Not only are there no distracting noises, but the room has a positive quality of its own - sorry, but that’s the best description I can write. Could be as Tomic says, "the baseline noise floor of the room."

I would add that books and articles on acoustics often discuss H x W x D in terms of opinion and rumour instead of science. The only way, IMO, is to do very many computer simulations. Cox and D'Antonio at Salford have done all this - all the heavy lifting. I am just the beneficiary.

@tomic601 , I had the same experience at Quietrock. After talking with them I bit the bullet and paid the bucks. May your project prosper!

Others here have suggested it, but I will reiterate that the most significant positive thing you can do for a room's modal distribution is to design it with modal distribution in mind.  With good H:W:D ratios you can do more to make a room sound good than any treatment added after the fact.  Way more.  Trying to fight bad room dimensions is a bandaid at best and phenomenally expensive if good.  Spend some time reading some acoustics books on studio control room design to understand how to control first order reflections without  treatment, and how to use treatment to fine-tune, not "fix" your room.  "Room correction" EQ remedies anomalies at the spot where the measurement is taken and usually makes things sound worse elsewhere.

You're in a unique position to fix your room problems at their root.  It would be a shame to just put it back together the same way and add various treatments (some which may work, some which may not) that fit a visual aesthetic when good ratios, construction, and geometry look purposeful and beautiful all by themselves.

@m-db nobody in right mind would trust a hack like me with your board...

I think some might be missing half the point, which is the baseline noise floor of the room. 

@terry9 thanks so much - I shall build some panels and learn :-)

I had a great back and forth w excellent customer service and technical support at Quietrock the 545 has a 32 mil galvanized steel barrier, I will try that soon.

In room treatment there is 3 possibilities:

You pay 50,000 dollars for an acoustically engineered room or even morre...

Or you buy costly acoustical materials and you made it yourself... But the cost will be a couple of thousand dollars mostly for quality materials.... But it will be a PASSIVE treatment made for the geometry and content of your room... (I used this passive way also but with cheap materials i dont have much money)

But if your room is not ideal, with odd dimensions and one the speaker is at an odd place in a corner (like mine), you are in a really bad shape.... :) Passive treatment work in some degree, with some limit...

But most people, dont know that it is possible to use ACTIVE controls to change the room acoustic.... Not by electronical equalizer.... But with a grid of ACTIVE generators connected to some grids of active resonators....

Then the sound image become totally holographic and completely decoupled from the speakers....

Yes it is possible, and the good news is that the cost is low....

My best to all...

@tomic601 

I used several hundred tubes of M1 caulk/glue and 20-30 tubes of BuildSecure construction glue, which is marginally stronger. Both are elastomeric.

Acoustic Sciences Corp. offers a fantastic product they named Wall Damp. It is part of a complete wall construction system, Wall Damp being a thin (1/16" iirc) viscoelastic material, available in 4" x 4" squares and long strips. I heard a mighty fine hi-fi in a room built using the complete ASC system, that of Audiogon member Folkfreak. Outstanding!

What is the Chemlink product ?

Decided against green glue and acoustic drywall. For one thing, it isn't a glue, IIRC. I had some experience with low VOC elastomeric glue, and went with modern incarnations from Chemlink.

Also, I suggest a supplier of commercial/industrial specialist drywall. That stuff has to make spec or there is hell to pay. I used Quietrock. Their 545 has a layer of sheet steel embedded into several (5?) distinct layers of drywall. It works. And it’s specced.

Or you could go to the friendly folks who don’t know much at your local building store.

With regard to carpet: do you have any down-firing subs? I have owned a few, and have experimented with them on wood floors and concrete floors, with and without carpet.

Carpet vs. hard surface under a down-firing speaker may get different results. May also be true of speakers with down-firing ports or down-firing passive radiators.

For those interested in soundproofing, you may want to check out the construction of my stereo house in "my system".

For those who appreciate science and the blacker arts, try ( pardon the pun ) cutting some carbon black powder into green glue.

i have done this with plugs for fireplaces and in a vocal booth , your mileage may vary

@avsjerry the product I use is Acousticork , it is foam and cork, ignore my error in quoting sorbothane. Never the less- effective. As for the Labrador, some small amounts of random are good

Lots of experience w green glue, works well w two layers of rock

chorus, sounds like you have the bases covered in your project.

I too have an exterior wall down to the studs that will be going back together in pretty short order, just need some electrical work, lighting etc.  Covid has slowed the process.
I will be soundproofing that wall because the A/C compressor is on the other side and I
can (barely) hear it, very annoying. 
You may be interested in this YouTube vid "Green Glue vs Mass Loaded Vinyl":
https://www.youtube.com/watch?v=jmgAgFZomd8

To all:  Does anyone have first hand experience with either of these products? I do believe that either will block the exterior noise, but I'm concerned that they may "deaden" my music room.
All comments are welcome. BTW the floor is concrete.

Thanks.  Regards, barts

 

If you are building anyway, building for acoustics can make big differences.  More than 8 ft ceilings and other dimensions is a start.  Try books like this before you start. https://smile.amazon.com/Handbook-Sound-Studio-Construction-Recording/dp/007177274X/ref=sr_1_38?dchild=1&keywords=building+a+home+studio&qid=1597839007&sr=8-38