Thank you, but fantastic on your part!
Oh my yes, my bad. I forgot to explain I have also not finished the drawing of the ports on the rears completely. But they are 1.625" x 1.625" and 6" long. That equals out to almost the minimum diameter that Unibox accepts. To yield a shorter vent. But yeah, itll workout, just havnt finished yet.
Great point actually. Maybe Ill make the back panel of the mids in the tower two pieces so it can slip down below and shimmy it out.
But I was thinking that, yet I do need that extra volume for the woofers though.
I did have success with the tweeters. Ill be sending them back today, and I got the new tweeters shipped to my grandparents so they will be there when I build.
Oh my yes, my bad. I forgot to explain I have also not finished the drawing of the ports on the rears completely. But they are 1.625" x 1.625" and 6" long. That equals out to almost the minimum diameter that Unibox accepts. To yield a shorter vent. But yeah, itll workout, just havnt finished yet.
Great point actually. Maybe Ill make the back panel of the mids in the tower two pieces so it can slip down below and shimmy it out.
But I was thinking that, yet I do need that extra volume for the woofers though.
I did have success with the tweeters. Ill be sending them back today, and I got the new tweeters shipped to my grandparents so they will be there when I build.
Can you not just use the existing side and top panels to make the slots work instead of adding extra pieces of wood? Ah, maybe the added strips for the removable backs will get in the way.
I wonder if 2 x 1" diameter round ports would work and just be easier too?
I wonder if 2 x 1" diameter round ports would work and just be easier too?
Sorry for the late reply, it has been a crazy week. First getting the wood was a nightmare, I cant believe I even have it still. But I got what I needed!
I have been building all week and I have all the pieces cut, inside and out. And I have the front baffles glued to the top&bottom and one side glued on. When I get back home I will be putting in the bracing and everything else. Then figuring out where to buy the absorption.
But I have decided to go with the triangle ports, yet I am going to use 1/4" wood instead of the 1/2" thats in that picture.
Also, I have ditched the starburst pattern window brace because it would take way too long to cut. Since drilling out a hole was easier and much quicker, I went with that. Also, you had said how changing the bracing shapes might help with standing waves. While that does seem like it still is a good idea, the absorption will deal with the standing waves.
Here is just a few photos from building.
I have been building all week and I have all the pieces cut, inside and out. And I have the front baffles glued to the top&bottom and one side glued on. When I get back home I will be putting in the bracing and everything else. Then figuring out where to buy the absorption.
But I have decided to go with the triangle ports, yet I am going to use 1/4" wood instead of the 1/2" thats in that picture.
Also, I have ditched the starburst pattern window brace because it would take way too long to cut. Since drilling out a hole was easier and much quicker, I went with that. Also, you had said how changing the bracing shapes might help with standing waves. While that does seem like it still is a good idea, the absorption will deal with the standing waves.
Here is just a few photos from building.
Attachments
That comment about getting the wood sounded like I stole it or something haha. To be clear I did buy it, straight from my Uncles supplier that is an hour and a half away. It was raining, and it just didnt fit in the van since I got three 5' x 5'. But a miracle happened from a good Samaritan that worked there, thankfully! Willing to help with straps. wrapping, and a tarp.
Then, it stopped raining on my way back!
Still cant believe it.
Then, it stopped raining on my way back!
Still cant believe it.
Yea, I was thinking - at gunpoint?
Just kidding.I was wondering if you had started the construction. Looks excellent. Don't worry about some of the smaller details - the right choices are the ones that work best for your priorities.
Keep up the good work.
Thank you very much!
First of all do you know of any good vendors for the absorption materials? I have found some sites that have reasonable prices, but I'm wondering if you have any good recommendations?
Also, while I am finishing construction. What do you suggest I do or start thinking about for the xo design? I know that'll be the next big thing to tackle.
First of all do you know of any good vendors for the absorption materials? I have found some sites that have reasonable prices, but I'm wondering if you have any good recommendations?
Also, while I am finishing construction. What do you suggest I do or start thinking about for the xo design? I know that'll be the next big thing to tackle.
First, be sure that you distinguish between damping and absorbing materials. Different materials and different purposes.
For sources, you can look at some of the diy suppliers like:
Parts Express
Madisound
Meniscus
But you'll find the big box stores are selling high and medium density mineral wool or denim insulation or other potential materials as well. Better value there but you usually have to buy larger quantities so you'll have to figure out what works for you. I like the heavier felt that you'll see Troels using frequently. It's also used to upholster furniture so you may find it for a better price at an upholstery supplier. I've also used memory foam bed topper for a medium density material.
Some type of bitumen sheet is usually used for panel damping. I'd just use that in your mid chambers and in the surrounds. Mass loaded vinyl might be good as well if you can get it in a small enough quantity. There are other diy solutions or recipes as well. You are after mass with little stiffness so I've seen people try heavy vinyl floor tiles, layers of roofing felt or even roofing tiles. I've made a concoction using Acousti-Seal caulking mixed with sand that has worked well but takes some effort and is a pretty messy procedure.
Once the cabinets are done, the next step is to measure the drivers' FR's and impedance in cabinet. Best to do that with the stuffing and damping in place. With your background, you may already know how to do this but if not these 2 tutorials are helpful:
Box
https://www.diyaudio.com/forums/software-tools/259865-xsim-free-crossover-designer-39.html#post5260072
For measurements, I use REW.
For xo work, I use XSim.
For sources, you can look at some of the diy suppliers like:
Parts Express
Madisound
Meniscus
But you'll find the big box stores are selling high and medium density mineral wool or denim insulation or other potential materials as well. Better value there but you usually have to buy larger quantities so you'll have to figure out what works for you. I like the heavier felt that you'll see Troels using frequently. It's also used to upholster furniture so you may find it for a better price at an upholstery supplier. I've also used memory foam bed topper for a medium density material.
Some type of bitumen sheet is usually used for panel damping. I'd just use that in your mid chambers and in the surrounds. Mass loaded vinyl might be good as well if you can get it in a small enough quantity. There are other diy solutions or recipes as well. You are after mass with little stiffness so I've seen people try heavy vinyl floor tiles, layers of roofing felt or even roofing tiles. I've made a concoction using Acousti-Seal caulking mixed with sand that has worked well but takes some effort and is a pretty messy procedure.
Once the cabinets are done, the next step is to measure the drivers' FR's and impedance in cabinet. Best to do that with the stuffing and damping in place. With your background, you may already know how to do this but if not these 2 tutorials are helpful:
Box
https://www.diyaudio.com/forums/software-tools/259865-xsim-free-crossover-designer-39.html#post5260072
For measurements, I use REW.
For xo work, I use XSim.
I found these online a while ago, what do you think? They seem like a reasonable price to me.
Bitumen acoustic damping matt | KJF Audio
30mm Polyester Speaker Damping Sheet | KJF Audio
Wool felt speaker dampening | KJF Audio
or
Echo Absorber Acoustic Panel (Natural Blend - 1"x4'x4') - Soundproof Cow
or this
Acry-Tech Acoust-X 1 Gallon Absorption Coating Paintable Damping Material
For the medium density material I was also thinking like a memory foam as well since I actually have a lot of them. Haha I put them up on the brick walls in my college apartments basement so my band could practice without almost infinite reverb. But they are all old and very soft, they seem like they would not be so much a medium material as more of a lighter material to use.
Something like this seems to be more of a medium density material to me:
https://www.parts-express.com/sonic...nd-damping-material-with-psa-18-x-24--260-530
Just wondering your thoughts on it all because I'm going to be buying soon.
Right now Im thinking on the bitumen sheets for the mid chambers and the rears.Then also for the mid chambers Id do the medium density foam, with then the polyester fill sheets.
Then maybe the Acoust-X paintable damping material on the woofer chambers with then the wool/cotton sheets, then the polyester fill sheets.
Bitumen acoustic damping matt | KJF Audio
30mm Polyester Speaker Damping Sheet | KJF Audio
Wool felt speaker dampening | KJF Audio
or
Echo Absorber Acoustic Panel (Natural Blend - 1"x4'x4') - Soundproof Cow
or this
Acry-Tech Acoust-X 1 Gallon Absorption Coating Paintable Damping Material
For the medium density material I was also thinking like a memory foam as well since I actually have a lot of them. Haha I put them up on the brick walls in my college apartments basement so my band could practice without almost infinite reverb. But they are all old and very soft, they seem like they would not be so much a medium material as more of a lighter material to use.
Something like this seems to be more of a medium density material to me:
https://www.parts-express.com/sonic...nd-damping-material-with-psa-18-x-24--260-530
Just wondering your thoughts on it all because I'm going to be buying soon.
Right now Im thinking on the bitumen sheets for the mid chambers and the rears.Then also for the mid chambers Id do the medium density foam, with then the polyester fill sheets.
Then maybe the Acoust-X paintable damping material on the woofer chambers with then the wool/cotton sheets, then the polyester fill sheets.
Let's summarize the damping and absorption strategies:
3-way vented woofer chambers - panel resonances, rear panel reflections and standing waves are expected to be outside the passband so simply line the walls with 1/2" - 1" felt padding and maybe a little lighter density fill but making sure not to block the port entrances. For the towers, adding extra fill at the bottom of the cabinet should help as well. If the cutouts in the braces line up make sure there is some fill in between them too.
Wall damping (~1/4") can probably be used on the walls if you want to without lowering the panel resonance frequencies back into the passband but isn't absolutely necessary. If you use it, I see its function as more to help attenuate overall sound transmission instead of panel resonances and so I would cover every square inch of panel surfaces. Note that any damping will reduce net volume though although the lighter fill effectively gives some of that back to you.
3-way sealed mid chambers - panel resonances, rear panel reflections and standing waves are all likely to be within the passband so start with damping all the walls. Damping effectiveness increases with thickness - for 3/4" plywood, 1/4" would be good but I think 1/2" would be better. You can add damping to the braces too if you want.
For absorption, I go with a layering strategy of increasing density as you move away from the drivers with extra thicknesses on the back panel while still leaving some breathing room behind the drivers. So for the back panel, I'm talking about 1.5"-3" of 4-6 lb/cu ft of compressed mineral wool or about 4" of something like denim insulation or Roxul Safe 'n Sound. But if you can only get those in bags of ~ 1' x 2' x 4' that doesn't make too much sense. Maybe look here if you can't find another alternative.
2-way vented surrounds - like the 3-way mid chambers, panel resonances, rear panel reflections and standing waves are all likely to be within the passband but since it's vented you can't stuff it the same way. So damp the walls again but then just use the stuffing strategy of the 3-way woofer chambers.
So if you haven't already, go over that and draw up a plan for the amount of square feet that you need of each material and then look at your choices again and how the prices work out. Going with the audio specific products can be pretty expensive sometimes so that's why I was trying to suggest a few alternatives. I went thru my bookmarks and found a few more sources that might be in the US too, or something similar anyways:
CLIMALOC Multi Purpose Insulation R8 - 2" x 16" x 48" CF21648 | RONA
Underpad and Underlay: End Of The Roll
Custom Foam & Mattress Manufacturer located in Vaughan and Toronto | Foamite for Comfortable Living
The Felt Store US | Shop Online Craft, Wool & Industrial Felt
– thefeltstore.com
Looking at your links, is the KJFAudio stuff from England? Shipping costs?
The Echo Absorber looks decent especially at 1" thickness.
The Acoust-X damping stuff I'm not sure about. I have used something like that before but this stuff is way cheaper and from what I can tell doesn't have very much mass so I again, I am unsure. It may work. It may not. Or it may work just a tiny bit. Sorry, can't help on that one.
3-way vented woofer chambers - panel resonances, rear panel reflections and standing waves are expected to be outside the passband so simply line the walls with 1/2" - 1" felt padding and maybe a little lighter density fill but making sure not to block the port entrances. For the towers, adding extra fill at the bottom of the cabinet should help as well. If the cutouts in the braces line up make sure there is some fill in between them too.
Wall damping (~1/4") can probably be used on the walls if you want to without lowering the panel resonance frequencies back into the passband but isn't absolutely necessary. If you use it, I see its function as more to help attenuate overall sound transmission instead of panel resonances and so I would cover every square inch of panel surfaces. Note that any damping will reduce net volume though although the lighter fill effectively gives some of that back to you.
3-way sealed mid chambers - panel resonances, rear panel reflections and standing waves are all likely to be within the passband so start with damping all the walls. Damping effectiveness increases with thickness - for 3/4" plywood, 1/4" would be good but I think 1/2" would be better. You can add damping to the braces too if you want.
For absorption, I go with a layering strategy of increasing density as you move away from the drivers with extra thicknesses on the back panel while still leaving some breathing room behind the drivers. So for the back panel, I'm talking about 1.5"-3" of 4-6 lb/cu ft of compressed mineral wool or about 4" of something like denim insulation or Roxul Safe 'n Sound. But if you can only get those in bags of ~ 1' x 2' x 4' that doesn't make too much sense. Maybe look here if you can't find another alternative.
2-way vented surrounds - like the 3-way mid chambers, panel resonances, rear panel reflections and standing waves are all likely to be within the passband but since it's vented you can't stuff it the same way. So damp the walls again but then just use the stuffing strategy of the 3-way woofer chambers.
So if you haven't already, go over that and draw up a plan for the amount of square feet that you need of each material and then look at your choices again and how the prices work out. Going with the audio specific products can be pretty expensive sometimes so that's why I was trying to suggest a few alternatives. I went thru my bookmarks and found a few more sources that might be in the US too, or something similar anyways:
CLIMALOC Multi Purpose Insulation R8 - 2" x 16" x 48" CF21648 | RONA
Underpad and Underlay: End Of The Roll
Custom Foam & Mattress Manufacturer located in Vaughan and Toronto | Foamite for Comfortable Living
The Felt Store US | Shop Online Craft, Wool & Industrial Felt
– thefeltstore.com
Looking at your links, is the KJFAudio stuff from England? Shipping costs?
The Echo Absorber looks decent especially at 1" thickness.
The Acoust-X damping stuff I'm not sure about. I have used something like that before but this stuff is way cheaper and from what I can tell doesn't have very much mass so I again, I am unsure. It may work. It may not. Or it may work just a tiny bit. Sorry, can't help on that one.
That is a great explanation of it all and makes so much sense!
Thank you for the links too to better sites that are in the US. I have been looking into all this and had some extra questions before I buy and have the final plan for damping and absorption.
In your last post you didnt say anything about any foam. I'm wondering where that would come into play, if at all. For the 3-way woofer chambers I agree that a 1/2" dense wool felt would be good with maybe one layer of the poly sheets in front of the felt, then more on the bottom. But what about foam? Maybe I can get away with a 1/4" wool felt and then like a 1/2"- 1" foam mattress? Not a super dense foam. Maybe that would be good as well? Which would work for me because I have a lot of old foam tempurpedic style foam mattresses.
Even if there were to be foam (either dense or not) in the mid chambers or 2-way vented surrounds, then how would that maybe play into the layers? Something I'm thinking of.
Also, what else do you recommend for the damping? I've heard everywhere to get bitumen sheets, yet there are not too make sites out there that have them for really great prices imo. Seems like thats one thing that ya gotta bite the bullet for.
Right now, I really like what you have said in the last post. My main direction will most likely be that way, but yet I am curious about a foam alternative.
I have been working on the speakers everyday. With the minimal clamps I have that are big enough, I have been chipping away at the gluing. Progress pictures to come soon this week!
Thank you for the links too to better sites that are in the US. I have been looking into all this and had some extra questions before I buy and have the final plan for damping and absorption.
In your last post you didnt say anything about any foam. I'm wondering where that would come into play, if at all. For the 3-way woofer chambers I agree that a 1/2" dense wool felt would be good with maybe one layer of the poly sheets in front of the felt, then more on the bottom. But what about foam? Maybe I can get away with a 1/4" wool felt and then like a 1/2"- 1" foam mattress? Not a super dense foam. Maybe that would be good as well? Which would work for me because I have a lot of old foam tempurpedic style foam mattresses.
Even if there were to be foam (either dense or not) in the mid chambers or 2-way vented surrounds, then how would that maybe play into the layers? Something I'm thinking of.
Also, what else do you recommend for the damping? I've heard everywhere to get bitumen sheets, yet there are not too make sites out there that have them for really great prices imo. Seems like thats one thing that ya gotta bite the bullet for.
Right now, I really like what you have said in the last post. My main direction will most likely be that way, but yet I am curious about a foam alternative.
I have been working on the speakers everyday. With the minimal clamps I have that are big enough, I have been chipping away at the gluing. Progress pictures to come soon this week!
If you have the time, I'm going to once again recommend reading the experiments augerpro is doing in this thread: A Monster Construction Methods Shootout Thread (link goes to the start of the insulation/fill tests).
Because unless anybody does controlled experiments like this, any information about insulation and damping etc that they suggest are mostly anecdotal, including me. And/or the suggestions are also very specific to exactly which materials are being used and how much of it and where it's being placed and so forth and so on. And I think that's why you don't see a lot of very specific guidelines in this area of speaker building. There has been a very sort of try it and see how it sounds kind of practice to this sort of thing.
Having said that as a preface, let me now say that there were 2 underlying bits of reasoning in my last post that I didn't articulate very well. One, that denser insulation is better at absorbing lower frequencies and 2, that different densities and types of stuffing seem to do better at different frequencies and sometimes unexpectedly so, and so using a layering of different densities and types will hopefully do a better job at absorbing a wider range of frequencies.
So what about your foam? I wasn't really sure about the quality of it but as a medium density stuffing, using that as a 2nd layer in the woofer chambers could work fine although I did some tests similar to augerpro's several years back and it didn't show much effect below about 600Hz. So maybe it's best considered as a slightly more lighter density stuffing. Which means it would be more suitable to the mid chambers and rear speakers.
The usefulness of foam might also depend on what you use as the densest layer. By this I mean if I was using rockboard as a 1st layer, I'd probably use some felt as a 2nd layer and then some wool or polyester as the third. But if I was using felt as the heaviest layer, then I might choose foam as the 2nd and again the polyester as the third one. Something along those lines to give you an idea.
But the hardest frequencies to absorb seem to be those below ~1kHz which is why I suggest very high density filling although I haven't seen any measurements on its effectiveness in speaker boxes. In manufacturers' spec sheets, the best stuff at LF absorption is considered to be 4-6lb/cu ft mineral wool (rockboard) and some Owens Corning FG boards (series 703 and 705?). In truth I didn't really expect that you might use these because they're not economical for a one-time build. Too much wastage in other words. Something that I forgot to mention though is that if you have to buy these products in larger quantities, they also happen to be some of the best stuff to make acoustic panels out of too. Which are really helpful in HT so that's just something else to consider. I mean if I was doing it, I would probably put it everywhere as the first layer. And that would also be the reason that I have about 2/3 of a bag of it that's just been sitting in a closet for the past 3 years. 😀
I came across these in another thread the other day though and they or something similar would seem to be a possible substitute for higher density stuff and look available in smaller quantities for decent prices:
https://www.amazon.com/BXI-Sound-Absorber-Absorption-Polyester/dp/B077Q2HYMW
And similar.
Re damping: yup, expensive for the bitumen sheets. Mass loaded vinyl if you can find it in small quantities. A box of heavy vinyl flooring tiles maybe plus the glue to layer them together and to the panel walls. Roofing tiles which are just bitumen and tiny rocks (ie flexible mass) plus the glue again to layer them together. Car audio has a number of similar products too but again, expensive. Recycled car tire rubber floor tiles/mats possibly but again, not cheap and not as heavy as mass loaded vinyl. Or there are other diy recipes out there but I can't attest to their efficacy.
That's for extensional damping but you might also think about constrained layer damping which is adding a 2nd layer of stiff material (wood, concrete board, real hard and heavy (ceramic?) tiles, etc.) with a viscoelastic layer in between (green glue). Resonances are damped via the energy loss of the sheering action of the 2 layers as the panels bend and resonate. Supposed to be better than extensional damping but I don't have a good enough handle on all the details to inform you on that topic.
Or you can go wild on google and do more research of course. Try 'soundproofing'. Here's 1 link of general info: Material for Sound Proofing and Sound Dampening | Phelps Industrial Products
Because unless anybody does controlled experiments like this, any information about insulation and damping etc that they suggest are mostly anecdotal, including me. And/or the suggestions are also very specific to exactly which materials are being used and how much of it and where it's being placed and so forth and so on. And I think that's why you don't see a lot of very specific guidelines in this area of speaker building. There has been a very sort of try it and see how it sounds kind of practice to this sort of thing.
Having said that as a preface, let me now say that there were 2 underlying bits of reasoning in my last post that I didn't articulate very well. One, that denser insulation is better at absorbing lower frequencies and 2, that different densities and types of stuffing seem to do better at different frequencies and sometimes unexpectedly so, and so using a layering of different densities and types will hopefully do a better job at absorbing a wider range of frequencies.
So what about your foam? I wasn't really sure about the quality of it but as a medium density stuffing, using that as a 2nd layer in the woofer chambers could work fine although I did some tests similar to augerpro's several years back and it didn't show much effect below about 600Hz. So maybe it's best considered as a slightly more lighter density stuffing. Which means it would be more suitable to the mid chambers and rear speakers.
The usefulness of foam might also depend on what you use as the densest layer. By this I mean if I was using rockboard as a 1st layer, I'd probably use some felt as a 2nd layer and then some wool or polyester as the third. But if I was using felt as the heaviest layer, then I might choose foam as the 2nd and again the polyester as the third one. Something along those lines to give you an idea.
But the hardest frequencies to absorb seem to be those below ~1kHz which is why I suggest very high density filling although I haven't seen any measurements on its effectiveness in speaker boxes. In manufacturers' spec sheets, the best stuff at LF absorption is considered to be 4-6lb/cu ft mineral wool (rockboard) and some Owens Corning FG boards (series 703 and 705?). In truth I didn't really expect that you might use these because they're not economical for a one-time build. Too much wastage in other words. Something that I forgot to mention though is that if you have to buy these products in larger quantities, they also happen to be some of the best stuff to make acoustic panels out of too. Which are really helpful in HT so that's just something else to consider. I mean if I was doing it, I would probably put it everywhere as the first layer. And that would also be the reason that I have about 2/3 of a bag of it that's just been sitting in a closet for the past 3 years. 😀
I came across these in another thread the other day though and they or something similar would seem to be a possible substitute for higher density stuff and look available in smaller quantities for decent prices:
https://www.amazon.com/BXI-Sound-Absorber-Absorption-Polyester/dp/B077Q2HYMW
And similar.
Re damping: yup, expensive for the bitumen sheets. Mass loaded vinyl if you can find it in small quantities. A box of heavy vinyl flooring tiles maybe plus the glue to layer them together and to the panel walls. Roofing tiles which are just bitumen and tiny rocks (ie flexible mass) plus the glue again to layer them together. Car audio has a number of similar products too but again, expensive. Recycled car tire rubber floor tiles/mats possibly but again, not cheap and not as heavy as mass loaded vinyl. Or there are other diy recipes out there but I can't attest to their efficacy.
That's for extensional damping but you might also think about constrained layer damping which is adding a 2nd layer of stiff material (wood, concrete board, real hard and heavy (ceramic?) tiles, etc.) with a viscoelastic layer in between (green glue). Resonances are damped via the energy loss of the sheering action of the 2 layers as the panels bend and resonate. Supposed to be better than extensional damping but I don't have a good enough handle on all the details to inform you on that topic.
Or you can go wild on google and do more research of course. Try 'soundproofing'. Here's 1 link of general info: Material for Sound Proofing and Sound Dampening | Phelps Industrial Products
Thank you for the, again, very informative post! I unfortunately do not have time to read that thread, things are getting really busy. Though I have been thinking about this for awhile and doing some research when I can.
Today I have been doing a lot of looking around the internet for the materials I need and looking at prices to gauge also what I should do. I have lots of things on my mind that I will just spill out in the most orderly fashion!
As an over view:
3-way Woofer Chamber: 3/4" wool felt everywhere but the front baffle, then 1" poly fill sheets. Will test with maybe some more poly fill.
3-way Mid Chamber: 1/8" mass loaded vinyl 1lb/sqft everywhere. Then 2" denim insulation on all walls but the front baffle, double thickness in the back. Then polyfill sheets, yet leave room for the drivers to breath.
2-way Surrounds: 1/8" mass loaded vinyl 1lb/sqft everywhere. Then 3/4" or 1/2" wool felt on all walls but the front baffle. Then some polyfill sheets.
So, I'm looking into damping for the Tower Mid-Chambers, Surrounds, and Center Mid-Chamber. You said to damp all the walls, so I'm guessing you are also including the front baffle, and the outside of the slot ports. Literally every surface. I have looked everywhere and here is the best site I found for the price and with the amount of sqft I need. Even with the $27 for shipping.
Now, Im looking into a 3/4" felt padding for the Tower/Center Woofer-Chambers and Surrounds. Yet, I can not find a website that sells cheap 3/4" felt padding anywhere. All the professional sites sell it for like ~$150 for 5sqft. I need ~30sqft of it.
All of the sites you and I have put in here only have 1/4" felt padding. Which I can layer, yet that would be even more expansive. So, Im at a loss there tbh.
That Meniscus site has a very reasonably priced polyfill 1" sheets (for everywhere), as well as denim insulation (for the 3-way mid-chambers). So, I will be going with them for those two things.
My foam idea wont happen fyi. I also would rather not want to work with a fiberglass insulation, yet I will if need be.
Today I have been doing a lot of looking around the internet for the materials I need and looking at prices to gauge also what I should do. I have lots of things on my mind that I will just spill out in the most orderly fashion!
As an over view:
3-way Woofer Chamber: 3/4" wool felt everywhere but the front baffle, then 1" poly fill sheets. Will test with maybe some more poly fill.
3-way Mid Chamber: 1/8" mass loaded vinyl 1lb/sqft everywhere. Then 2" denim insulation on all walls but the front baffle, double thickness in the back. Then polyfill sheets, yet leave room for the drivers to breath.
2-way Surrounds: 1/8" mass loaded vinyl 1lb/sqft everywhere. Then 3/4" or 1/2" wool felt on all walls but the front baffle. Then some polyfill sheets.
So, I'm looking into damping for the Tower Mid-Chambers, Surrounds, and Center Mid-Chamber. You said to damp all the walls, so I'm guessing you are also including the front baffle, and the outside of the slot ports. Literally every surface. I have looked everywhere and here is the best site I found for the price and with the amount of sqft I need. Even with the $27 for shipping.
Now, Im looking into a 3/4" felt padding for the Tower/Center Woofer-Chambers and Surrounds. Yet, I can not find a website that sells cheap 3/4" felt padding anywhere. All the professional sites sell it for like ~$150 for 5sqft. I need ~30sqft of it.
All of the sites you and I have put in here only have 1/4" felt padding. Which I can layer, yet that would be even more expansive. So, Im at a loss there tbh.
That Meniscus site has a very reasonably priced polyfill 1" sheets (for everywhere), as well as denim insulation (for the 3-way mid-chambers). So, I will be going with them for those two things.
My foam idea wont happen fyi. I also would rather not want to work with a fiberglass insulation, yet I will if need be.
Actually foam isnt completely out of the question. I'm thinking of using foam as a substitute for the denim insulation.
Okay so I actually found some roof tiles on my basement that I will use since it's free! I'll use Liquid Nails to glue them to the cabinets.
Then, I'm still thinking of using the lighter foam mattresses for the substitution of the denim insulation. Since, I have foam mattresses at my disposal. I even have one thats about 3" thick.
I also have old pillows I can use for light fill if needed, but I'm still going to get the polyfill sheets.
Last thing to find is a better price on the 1/2" or 3/4" felt. Or just bite the bullet on that one.
Then, I'm still thinking of using the lighter foam mattresses for the substitution of the denim insulation. Since, I have foam mattresses at my disposal. I even have one thats about 3" thick.
I also have old pillows I can use for light fill if needed, but I'm still going to get the polyfill sheets.
Last thing to find is a better price on the 1/2" or 3/4" felt. Or just bite the bullet on that one.
Wow I forgot you gave me some links to some dense acoustic panels on Amazon that look like they would actually work very well!
Okay so here is what I'm thinking is the final layout, in my mind! Please let me know if you see any problems here. But gathering from what you've said this seems like a solid plan.
3-way woofer chambers: in order from the wood
- Liquid Nails
- These acoustic panels which are 3/8" thick, but they are pretty dense and I looked back at Troels Gravesen and they use 8mm felt. So 3/8" is actually slightly bigger anyways.
- Then these polyester batting sheets
3-way mid chamber: in order from the wood
- Liquid Nails
- The roofing tiles, probably only two layers
- Liquid Nails
- The Amazon acoustic panels
- Foam mattress
- The poly batting
2-way surrounds: in order from the wood
- Liquid Nails
- Roofing tiles
- Liquid Nails
- The Amazon acoustic panels
- the poly batting
Okay so here is what I'm thinking is the final layout, in my mind! Please let me know if you see any problems here. But gathering from what you've said this seems like a solid plan.
3-way woofer chambers: in order from the wood
- Liquid Nails
- These acoustic panels which are 3/8" thick, but they are pretty dense and I looked back at Troels Gravesen and they use 8mm felt. So 3/8" is actually slightly bigger anyways.
- Then these polyester batting sheets
3-way mid chamber: in order from the wood
- Liquid Nails
- The roofing tiles, probably only two layers
- Liquid Nails
- The Amazon acoustic panels
- Foam mattress
- The poly batting
2-way surrounds: in order from the wood
- Liquid Nails
- Roofing tiles
- Liquid Nails
- The Amazon acoustic panels
- the poly batting
That sounds better to me. I was just writing this up as you posted so now here's an edited version.
I have a sort of rule of proportion that I use which sort of says that the quality of the cabinet and the damping and the absorption etc as well as the quality of the xo components should be about equivalent to the quality of the drivers. It sort of works with the amount of money I spend in each category too. So you've picked some very good drivers, particularly good value drivers but they are not exactly ScanSpeak Revelators, or SB Acoustic Satori's or Accuton ceramics or so on. So I'm not sure I'd be spending too much money on cabinet fill when all is said and done. Unless of course you really want to......
Re extensional damping: a thin layer like 1/8" is unfortunately almost useless up against 3/4" wood. Up against 1" wood it'll be totally useless. I was doing some further reading into damping and below is a chart I came across showing damping effectiveness (vertical scale) against the relative thickness of top layered damping - which just confirmed for me that extensional damping needs to be at least 1/2 the thickness of the rigid panel thickness if not more to be effective.
So with roofing tiles make them about as thick as you can. And I think what is very important is to bond them together well enough so that they form essentially 1 thick solid heavy but flexible mass. And bond it well to the panels too. PL Premium is my glue of choice for this type of heavy duty application but Liquid Nails may be just about as good but I'm not sure about that.
augerpro happened to test that Acoust-X stuff btw and it showed no measurable effects. So yea, stay away from that one.
If you can't find felt at a reasonable price, I'm just going to say perhaps just scrap that idea all together. So instead I went looking for some Roxul Rockboard in your area but I found that the Owen Cornings version is what your Home Depot sells instead: https://www.homedepot.com/p/Owens-Corning-Thermafiber-Fire-and-Sound-Guard-Mineral-Wool-Insulation-Batt-15-in-x-47-in-SG-25-P3-15-47-221/303347027. That's $42 for 49 sq ft at 3" thickness and that's actually pretty good value. You can keep it at 3" thick for the back walls (or even 4" perhaps) but I might suggest cutting it down to 1.5" or 1" thick to line all the rest of your walls for all the speakers. Cuts pretty easily with just something like a bread knife. Or even a hand saw. Not hard to work with at all. It's not like the old loose fiber glass stuff at all. You just want to make sure that no fibers escape into the driver vent holes or out the port though. So perhaps for the next layer, cover all the mineral wool with your memory foam, or polyester batting and/or head down to your local re-use it store (Value Village?) and look for some thick soft blankets or towels or some such to cover the stuff with. I found some lovely red velvet curtains once that I'm still using for this very purpose. And I've just used a spray adhesive glue them together. And for the driver rear vents, cover them with nylon stockings.
My rough calculations suggest you'll have some of the mineral wool left over but it's still a good value. I was looking at the square footage of some of that denser 'felt' acoustic panels I linked to previously, and they don't come close in terms of price per coverage. I think in your link, you get 8 sq ft at 3/8" thick for $23 compared to $43 for 98 sq ft at 1.5" thick of mineral wool.
Sorry, just finished this before your last post, but it should still apply. In particular, the damping layer needs to be thick(er) and a spray adhesive can probably substitute for the liquid nails in all the spots not having to do with the damping tiles.
I have a sort of rule of proportion that I use which sort of says that the quality of the cabinet and the damping and the absorption etc as well as the quality of the xo components should be about equivalent to the quality of the drivers. It sort of works with the amount of money I spend in each category too. So you've picked some very good drivers, particularly good value drivers but they are not exactly ScanSpeak Revelators, or SB Acoustic Satori's or Accuton ceramics or so on. So I'm not sure I'd be spending too much money on cabinet fill when all is said and done. Unless of course you really want to......
Re extensional damping: a thin layer like 1/8" is unfortunately almost useless up against 3/4" wood. Up against 1" wood it'll be totally useless. I was doing some further reading into damping and below is a chart I came across showing damping effectiveness (vertical scale) against the relative thickness of top layered damping - which just confirmed for me that extensional damping needs to be at least 1/2 the thickness of the rigid panel thickness if not more to be effective.
So with roofing tiles make them about as thick as you can. And I think what is very important is to bond them together well enough so that they form essentially 1 thick solid heavy but flexible mass. And bond it well to the panels too. PL Premium is my glue of choice for this type of heavy duty application but Liquid Nails may be just about as good but I'm not sure about that.
augerpro happened to test that Acoust-X stuff btw and it showed no measurable effects. So yea, stay away from that one.
If you can't find felt at a reasonable price, I'm just going to say perhaps just scrap that idea all together. So instead I went looking for some Roxul Rockboard in your area but I found that the Owen Cornings version is what your Home Depot sells instead: https://www.homedepot.com/p/Owens-Corning-Thermafiber-Fire-and-Sound-Guard-Mineral-Wool-Insulation-Batt-15-in-x-47-in-SG-25-P3-15-47-221/303347027. That's $42 for 49 sq ft at 3" thickness and that's actually pretty good value. You can keep it at 3" thick for the back walls (or even 4" perhaps) but I might suggest cutting it down to 1.5" or 1" thick to line all the rest of your walls for all the speakers. Cuts pretty easily with just something like a bread knife. Or even a hand saw. Not hard to work with at all. It's not like the old loose fiber glass stuff at all. You just want to make sure that no fibers escape into the driver vent holes or out the port though. So perhaps for the next layer, cover all the mineral wool with your memory foam, or polyester batting and/or head down to your local re-use it store (Value Village?) and look for some thick soft blankets or towels or some such to cover the stuff with. I found some lovely red velvet curtains once that I'm still using for this very purpose. And I've just used a spray adhesive glue them together. And for the driver rear vents, cover them with nylon stockings.
My rough calculations suggest you'll have some of the mineral wool left over but it's still a good value. I was looking at the square footage of some of that denser 'felt' acoustic panels I linked to previously, and they don't come close in terms of price per coverage. I think in your link, you get 8 sq ft at 3/8" thick for $23 compared to $43 for 98 sq ft at 1.5" thick of mineral wool.
Sorry, just finished this before your last post, but it should still apply. In particular, the damping layer needs to be thick(er) and a spray adhesive can probably substitute for the liquid nails in all the spots not having to do with the damping tiles.
Attachments
Right, use only open cell foam to damp most cabs, closed is only good for damping high pressure under-damped alignments such as low tuned TLs and even then a ~aperiodic vent is normally a better choice.
Don't know if this many decades old suggestion is of any use nowadays is to buy [usually for free in my time since installers had to pay to get rid of most of it otherwise, leaving only scraps under furniture, etc.] the dense felt used under premier carpet installs. Just strips/patches of it strategically placed does a great job of toning down a cab's internal eigenmodes.
GM
Okay yeah that damping to wall thickness proportions makes a ton of sense. I was thinking how 1/8" heavy vinyl can do much up against 3/4" baltic birch. so thank you for that, yeah Ill make sure that the roofing tiles are stacked to about a half inch or so. I have used liquid nails a lot for construction before and it does a great job, plus I have like 6 tubes at my house that I can already use.
Haha good to know about the Acout-x stuff. It did seem very odd to me, but yet the marketing had me curious.
So the Rockboard is a good price effective way to substitute the felt. Though, I have used that stuff before for home install and its not very dense. I have nothing to back myself up on, but I feel like that stuff at 1.5" would be doing that same job as the foam.
Plus, if there can be some extra money spent on the Amazon felt for ease of installation. Then I might do that to save the trouble of cutting the Rockboard down to 1.5" and then needing to use the blankets.
Only since, yet again, I do have somewhat of a deadline. Since my brother will be here from Texas for Xmas, thatll be the last time in a long time I'll see him. So, it would be preferred by him that I get it done by then. Yet, idk how realistic that is. Haha we'll see.
Haha good to know about the Acout-x stuff. It did seem very odd to me, but yet the marketing had me curious.
So the Rockboard is a good price effective way to substitute the felt. Though, I have used that stuff before for home install and its not very dense. I have nothing to back myself up on, but I feel like that stuff at 1.5" would be doing that same job as the foam.
Plus, if there can be some extra money spent on the Amazon felt for ease of installation. Then I might do that to save the trouble of cutting the Rockboard down to 1.5" and then needing to use the blankets.
Only since, yet again, I do have somewhat of a deadline. Since my brother will be here from Texas for Xmas, thatll be the last time in a long time I'll see him. So, it would be preferred by him that I get it done by then. Yet, idk how realistic that is. Haha we'll see.