NEW Basement Studio Design in New York. Looking for advice

[Waka]

Hi, just noticed your thread!
It's looking good.

You could use a deadbolt with a thumb turn on the inside for your external door.

Something like this

The thumb turn means you can unlock from the inside without a key, which is required in alot of places for fire safety reasons.

Dan

[Soundman2020]

Yes the speakers are extremely large they are Urei 813's. I believe the speakers plus the mdf boxes came to around 520 lbs each.

You actually helped me do the calculations on how many of those pads to use. They are Duro 50 and with the 17 pads they are at 22% deflection.

You are so right! Man, that was something like 5 YEARS ago, and I had completely forgotten about that. Yeah, now I remember.

There is no additional sorbothane planned in the system, just the pads you see in the photos.

Hmmm.... Way back then, I did mention to you that there are also lateral forces acting on your speaker: as the cone slams forwards and backwards, moving all that air around, the speaker also wants to slide backwards and forwards: action and reaction. The pads you have are fine for vibration in the vertical direction (up and down), but not so much for the other two directions: side to side, and forwards/backwards. The speaker will be moving and vibrating in all three directions, not just up and down. And since your speaker is large, tall, and top-heavy, it will probably end up "rocking" back and forth a little bit, on top of the pads you have. You should have some method for dealing with the vibrations in those directions too. I have developed a proprietary method for doing that for my clients, when I design their soffits, but that's not something I hand out in public. But it's not hard to figure out: you just need Sorbothane pads on the other 5 sides of your speaker, not just under it. And since those other pads don't have to support the weight of the speaker (just deal with the vibration), you won't need as many of them, and they can be smaller.

The mdf boxes will be built snugly/tightly around the speakers. I was not planning on having any rubber between the actual speaker and the mdf box. I am hoping this is not a mistake, I got the advice to do that from this site as well.

There's two basic methods for soffit-mounting speakers, and you might be confusing them. One method is the way I do it, which completely "floats" the speaker inside the soffit such that it can vibrate freely in all directions without transferring any of that to the soffit structure. The other method (which John prefers) is to hold the speaker so rigidly that it cannot move, and therefore cannot transfer vibrations into the soffit structure. You seem to be combining both into one! But you can't do that...

It looks like you might need to update your soffit design a bit...


- Stuart -

[richroyc]

[quote]There's two basic methods for soffit-mounting speakers, and you might be confusing them. One method is the way I do it, which completely "floats" the speaker inside the soffit such that it can vibrate freely in all directions without transferring any of that to the soffit structure. The other method (which John prefers) is to hold the speaker so rigidly that it cannot move, and therefore cannot transfer vibrations into the soffit structure. You seem to be combining both into one! But you can't do that.../quote]

So I was basically planning on the first method you mentioned. The plan was also to have the mdf box rigidly attached to the speakers. However the mdf box AND speaker together is completely "floated" inside the soffit. That mdf box doesn't touch anything except the pads.The only real purpose of the mdf box was so that I did not have to drill holes on the underside actual Urie speakers bottoms. So essentially, the mdf and speakers are vibrating together as one.

I understand that speakers are designed a certain way (weights, dimensions, materials, etc..) to achieve a certain sound, and that adding the mdf may effect that design. But I just needed a way to fasten the speakers to the pads underneath. I am hoping that I didn't mess something up with this design. It is definitely not too late to change the design slightly, (i.e. completely eliminate the mdf box, screw a few holes on the underside of the Urei box, and re-calculate the proper amount of sorbothane pads now that it is lighter). However, the blocks are already there, so that part can't really change - and the mdf board is already cut to into pieces ready to become boxes sop that would be sort of a waste of money since I can.t really use it elsewhere.

I would assume that with Johns method of mounting a speaker so rigidly that the actual speaker box doesn't move at all, would also have a similar effect as adding weight?

For the lateral movement of the speakers, those pads I am using are not just flat pads - they are called stud mounts, and they have a threaded piece sticking out each side maybe 1/2" or so, something like this:

stud mount.jpg

This should prevent any lateral movement cause by normal operation of the speaker (vibration). However you are definitely correct that these could be tipped over if you just press on the side. Its something I was planning on being cautious about during the construction of the soffit walls, once the walls are built around the speakers, there will be no access for anyone to be able to push the speaker as it will be inside the wall. I guess someone could technicality push the front of the speaker BACK into the soffit, but I think what would happen there is that before the box could tip over, the top would hit the top of the soffit face. I'm aiming at getting somewhere less than 1/4" between the speaker and the soffit face.

You had actually told me to private message you about this proprietary method you are talking about all those years back but you never responded!

Let me know if you think I'm on the right path or headed to disaster!

[Soundman2020]

The only real purpose of the mdf box was so that I did not have to drill holes on the underside actual Urie speakers bottoms. So essentially, the mdf and speakers are vibrating together as one.

That's fine! Some people do it that way. It also has the advantage of adding mass to the speaker cabinet itself, which is a good thing.

I understand that speakers are designed a certain way (weights, dimensions, materials, etc..) to achieve a certain sound, and that adding the mdf may effect that design.

999 times out of a thousand (invented statistic, but you get the point...), that will IMPROVE the sound. Speaker manufacturers go to great pains to make their cabinets as rigid and massive as they can, but there are practical limits... such as shipping costs, for example: A speaker with a 6" thick concrete case around it would be great, but the shipping might be a little steep. Probably not too many buyers, either: Nobody wants to have to hire Chunk Norris AND Arnold Schwarzenegger, just to lift the speaker out of the box, and onto the desk! (Which then collapses under the weight... ) Silly analogy! Anyway, just wanted to relieve your concerns that adding mass and rigidity to the box might change things in a bad way: it wont. It will either be neutral, or good. I'm betting on "good".

I am hoping that I didn't mess something up with this design.

It's fine! It will work. But I still would suggest considering pads around that, to keep it all happy...

However, the blocks are already there, so that part can't really change - and the mdf board is already cut to into pieces ready to become boxes sop that would be sort of a waste of money since I can.t really use it elsewhere.

The blocks are fine! No problem. Might even be over-kill, but it's a hell of a solid, massive base! There's no need to do anything to that.

My concern here is that, with a large powerful speaker like that, there's quite a bit of mass slamming around inside the box, which in turn can potentially cause the box to want to move forwards and backwards on top of the pads. Those Sorbothane studs you have are designed to support the weight of the speaker, acting vertically downwards, and to deal with any vibration in that direction. That's what they are tuned for, and that's what they will do. But if there are lateral forces acting side-to-side, or front-back, those pads are not going to be able to deal with that correctly, because the speaker is so tall. At low volumes, it's not going to be an issue, but when you turn it up to eleven, there's a lot of inertia going on inside, with the woofer mechanism chugging away merrily: action/reaction. There mass moving at high speed, the suddenly reversing direction and going back the other way, then repeating the cycle, ad infinitum. However, since the bottom of the cabinet is restrained by the studs, but the top is free to move, there's a potential for that inertial mass thumping away, to cause the entire speaker to rock back and forth on top of the pads.

This might not actually be a real issue, in your case! So don't sweat it too much. Do some testing first, and see if you even have a problem. If you do, then we can figure out solutions. If not, then you can sleep soundly again. So set up one speaker completely, turn it up to eleven, play lots of bass-heavy music, and see if the speaker actually does "rock" at some frequencies. Also run some pure sine test tones through the speaker at high power, and ramp up the frequency slowly, so see if there's any type of strange resonance that might cause it to "rock" at one specific frequency.

I don't want to scare you and say that you definitely will have this issue, and it will make your sound terrible, and tear your room apart! I don't like scare-mongering... There's just a potential for this to happen. Your speakers are so massive already that the effect might be negligible. It can be an issue with smaller, light speakers run at high power, but yours might be heavy enough to not even be bothered.

I would assume that with Johns method of mounting a speaker so rigidly that the actual speaker box doesn't move at all, would also have a similar effect as adding weight?

Yes... sort of! But with a speaker that large, it would be an "interesting" exercise...

For the lateral movement of the speakers, those pads I am using are not just flat pads - they are called stud mounts, and they have a threaded piece sticking out each side maybe 1/2" or so, something like this:

I'm familiar with those, yes. I have used that exact thing for HVAC compressor isolation mounts, and other things. And I've actually seen one case where the pads worked fine for up-and-down motion of the compressor, isolating perfectly during normal operation, but they were totally shredded and torn to bits, dumping the compressor down onto the mounting brackets, when they failed during start-up, due to the lateral forces acting on them as the compressor spun up to speed... At very low speeds, the compressor speed ramped up through the resonant frequency of the pads, and at that specific frequency there was enough vibration in all directions to rip the Sorbothane to pieces. Not the fault of the rubber, of course! The fault of the design. You should take other precautions if the isolation mounts will ever experience vibration at their natural resonant frequency, due to the amplification of the forces.

Now, don't worry! That's NOT going to happen with your speakers! They are not HVAC compressors, and they'll never be producing frequencies in the resonance range, that could provide such destructive vibration. But it does illustrate the point that there are OTHER forces acting on those studs, not just gravity and vertical vibration.

This should prevent any lateral movement cause by normal operation of the speaker (vibration).

Mmmmm.... maybe not! See above.

However you are definitely correct that these could be tipped over if you just press on the side.

Red flag!

once the walls are built around the speakers, there will be no access for anyone to be able to push the speaker as it will be inside the wall.

Maybe people can't get in there, but other forces could... have you ever seen the massive air pressure changes that a large speaker cone can produce inside a box?

I'm aiming at getting somewhere less than 1/4" between the speaker and the soffit face.

That's side-to-side, but what about front-back motion? There's nothing to stop the speaker moving in that direction... and it's quite possible that a real person COULD push on the front face of the speaker, forcing it backwards into the soffit. Either by accident, or on purpose....

I always try to get that gap down to 5mm, then use 6mm high flexibility closed-cell foam all around the edge, to get the air-tight seal. You don't want air huffing and puffing though that gap, as the woofer woofs...

You had actually told me to private message you about this proprietary method you are talking about all those years back but you never responded!

That's weird! I really don't recall seeing that at all! Sorry about that.... Try again, if you feel up to it...


- Stuart -

[richroyc]

Also run some pure sine test tones through the speaker at high power, and ramp up the frequency slowly, so see if there's any type of strange resonance that might cause it to "rock" at one specific frequency.

Image-Tacoma_Narrows_Bridge1.gif

I don't want to scare you and say that you definitely will have this issue, and it will make your sound terrible, and tear your room apart! I don't like scare-mongering... There's just a potential for this to happen. Your speakers are so massive already that the effect might be negligible. It can be an issue with smaller, light speakers run at high power, but yours might be heavy enough to not even be bothered.

Attention to every single detail is why I come here. I'll set everything up one one side and run some tests as you mentioned as see how it looks. I'm hoping the fact that I'm using a crossover may help a bit since I'm only sending 80Hz and above to these speakers.

That's weird! I really don't recall seeing that at all! Sorry about that.... Try again, if you feel up to it...

No worries, I will def shoot you another message I know you're a busy man Stu!!!

I do have one quick question. Should I put this insulation in here or no?

Conc Speaker Stand 2.jpg

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It's just 703 - I cut it thin enough to account for the 22% deflection so that the insulation won't be compressed at all. I figured it easier to just do this and take a photo rather than design or describe it - so if it's wrong I can just remove it.

[Soundman2020]

Should I put this insulation in here or no?

Definitely!


- Stuart -

[richroyc]

So I've been making a ton of progress! I'll have a bunch of photos to post next!

For now I had a question regarding fabric underlayment.

According to Guilford of Maine - they recommend using Tyvek as a opacity layer/underlayment - just behind the finish layer of fabric and to cover the wood/703 behind it.

I know Stuart has mentioned that any cheap fabric will work as long as it is breathable.

So I have a bunch of FREE rolls of this stuff laying around at my shop at work.

It is definitely breathable.

Reinforcing Fabric:
http://www.mapei.com/US-EN/Tile-&-Stone ... ing-Fabric

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Would this work? (by the way - I don't think this product is waterproof by itself, its part of a membrane system under tile and possibly some roofing applications)

[richroyc]

here's a few update photos as well - i know they are not quality pics but I haven't cleaned up the place enough to take out the good camera and have a photo shoot yet.

Progress pics:
Superchunk in corner behind speaker stand (with a temp bass hanger for placement)

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Bass hangers before being lowered into place. There are a total of 9 bass hangers below each speaker box + surrounding the concrete speaker stands.

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Speaker box before fill

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Where I'm at now:

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I DID run the tests as Stuart mentioned (played loud music and swept a sine wave) to make sure there were no strange vibrations or harmonic reaction that cause the speakers to wobble.

The framed soffit wall isn't touching the speaker box at all - there's a gap there I'll take some close-up pics of that. If I push on the speaker box with my hand, I can rock it back and forth slightly (it is only sitting on those sorbothane pads) I can take a short video to show this. The pink fluffy insulation isn't packed tight at all, just basically laying in there along with all of the scraps I've accumulated during the whole process. Once I put in a few more noggins, I'm pretty much ready for my front soffit walls to go in.

That box in between the speakers is my "Machine Room" or basically just my power amp box. It is tied into the AC system (that is that 4" flex duct back there)

The speakers themselves are also passively vented with chicken wire chimney through all that pink fluffy stuff. They exit not toward the face of the speaker, but rather towards the middle. That middle area that is open now, will have a small 28" TV flush mounted just above the AMP box. The wall will be finished with fabric, and behind it, probably (2) more bass hanger traps to either side of the box (more if I can fit them). If you zoom into the photo - you may even be able to see the small stub of the chicken wire chimney sticking out (right next to the 4" silver flex duct). That AMP box also has a chimney (not attached yet - its actually that thing on the floor in the bottom right of the last photo) with duct liner and the bottom section of the box is a baffle box (you can see the inlet bottom left). It will have a glass door in the front to seal it up. I may have went overkill isolating the amps as the fans noise isn't exactly low frequencies that are the most diff to isolate. So it is made of only (1) layer of 5/8" OSB.

[Soundman2020]

So I have a bunch of FREE rolls of this stuff laying around at my shop at work.

It is definitely breathable

It looks like it should work from the acoustic point of view, but I'm not so convinced about the aesthetics. The main purpose of that rear liner is to make it hard to see inside, through the weave of the finish fabric. I use black cloth for that, as it seems to block light better than white cloth. You are trying to stop as much light as possible getting into the device, and also stop as much light as possible coming back out. That stuff you have might be fine for that: I would try it out and see how it goes on a large test section, done temporarily. If it works, and you can't see anything inside, then greate! But if if doesn't work well, then switch over to cheap black cloth.

Speaker box before fill

Man, those things are huge! You don't really appreciate the full scale of them, visually, until you see it like that.

One comment: I'm not sure that the gap is large enough, right down near the floor, between the bottom of the absorber box and the floor. That "slot" down there should be at least 12" high (30 cm). Yours doesn't look that big...

Another comment? What are you plans for the ceiling? Normally, you would have an angled, hard-backed cloud up there, but your speakers are so huge and the ceiling is low, so I'm not sure you'll be able to do that: the cloud would be partly covering the speaker. That's going to be a challenge...

I DID run the tests as Stuart mentioned (played loud music and swept a sine wave) to make sure there were no strange vibrations or harmonic reaction that cause the speakers to wobble.

And all is OK? No vibrations or wobbles?

If I push on the speaker box with my hand, I can rock it back and forth slightly

Right, but does it do that when you are playing loud, low-frequency sounds, such as a thumping kick drum or floor tom? Or maybe a six string bass playing way down low?

It's coming along nicely, though! Looking good...

- Stuart -

[richroyc]

Stuart! Always great to get a response from you!

But if if doesn't work well, then switch over to cheap black cloth.

I'll stop at the store today and get a small roll of black fabric, and a see which one works better, I guess black makes more sense. Also this white stuff is not the most opaque fabric so I think you may be right.

One comment: I'm not sure that the gap is large enough, right down near the floor, between the bottom of the absorber box and the floor. That "slot" down there should be at least 12" high (30 cm). Yours doesn't look that big...

Yeah you're definitely right about that! thanks for catching that, it should be a pretty easy fix, i think I can cut it up a bit higher without having to remove the wall at all, just carefully get a sawzall in there.

Another comment? What are you plans for the ceiling? Normally, you would have an angled, hard-backed cloud up there, but your speakers are so huge and the ceiling is low, so I'm not sure you'll be able to do that: the cloud would be partly covering the speaker. That's going to be a challenge...

So I am planning on doing some form of a cloud, but as you mentioned I don't have a lot of space to work with AT ALL. I actually originally planned to have my return duct run overhead in that same area so I would have symmetrical air-flow, but there was just no room for it (even if i pancaked the duct to it's max, it would have been like 28" x 4" before insulation to maintain the 300 FPM). So now my return duct/grill is to the left side of the room. I'll try to make this more clear with some photos and/or sketchup.

I also am planning on putting a TV/Monitor between the speakers, pretty high up as well. So yeah this is definitely a big challenge. I probably won't get to do the normal hard backed cloud you mentioned, maybe I'll be able to get a few inches of trapping up there? Any suggestions would help.

Now I don't know if this SORT of helps the situation, but the center listening axis on these speakers is from the bottom 15" driver (dual concentric/coaxial driver). The top 15" driver is the subwoofer. On top of that, I have an external crossover at 80Hz. So I'm not saying that the top cone isn't doing ANYTHING, but it's definitely doing a whole lot less less that it would without the crossover. Inside the Urei box, there is a 3-way network. Trying to find info on the actual bottom crossover freq is a bit difficult. The top subwoofer was often referred to as the "helper woofer". From what I gather it was crossed over as low as 100Hz. So the top woofer may only be doing the work of producing around +/- 80Hz-100Hz range. This is why I'm thinking more trapping may be better that reflecting overhead?

So I think whatever cloud I do install, can go pretty much as low as the top of the cone, or maybe even lower? (might look weird). Its about 6-7" to the top of the speaker box from the ceiling, and maybe 10" roughly to the top of the cone/woofer. So I was hoping I could get the cloud down as low as 10" in the front of the room (may cover the top of the speaker box itself, but not the cone), and just angle it back from there. If I partially obstruct the top cone, I can go 12" down in the front of the room.

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I know I need a good angle to maintain my RFZ in the vertical plane which is going to be the main challenge.

And all is OK? No vibrations or wobbles?

all good. I tested it WITHOUT the crossover as well so it was getting full range. I went real slow with the sine wave generator in all the low freq's to see if I could get a reaction out of them but nothing. Tried some deep house music as well and some other stuff with a deep kick and bass. No visible movement at all. the only time I can get visible movement (rocking, wobbling) is if i push it by hand. Also, although the insulation is loosely filled, there is definitely noticeably less rocking/wobbling that happens when I push the box now that is filled. I think just the weight of the insulation itself sitting on top of the box, and the friction along the sides, is somewhat dampening the rocking even further. I hope this is a good thing. There's definitely no flanking or overly compressed insulation anywhere. The extreme weight of these things gives it a very firm/solid feel overall.

It's coming along nicely, though! Looking good...

honestly this is the best thing I've heard all year. Thanks StuArt!

[richroyc]

everything is taking forever but here is a few update photos:

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[Gregwor]

It is looking awesome!!!! Keep up the good work!

Greg

[richroyc]

few more update pics

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[richroyc]

more pics!

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[gullfo]

very very nice.

although pink lighting can cause aggression, not sure why but there was a study done about 15 or so years ago on different colored light effects on people and the researchers were surprised by heightened tensions and increased aggression of pink light. so maybe save the pink lights for the heavy metal sessions