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Home Studio Build: Sharing my step by step build done by Professional Acoustic Engineers
Old 4 days ago | Show parent
  #1201
Lives for gear
 
🎧 5 years
Quote:
Originally Posted by avare ➑️
outside as in the garden for example.
Okay, you really want to compare the room to the pure source.

I'm only afraid of volume levels for neighbours. If I pump around 70dB is that sufficient?

I'm a bit confused on how testing them in the garden will be beneficial with the firm. Of course it's useful to know how the monitors work in an open space, but the firm guaranteed a certain result in the studio, regardless of how the monitor's sound in an open space. Is there a (maybe obvious) reason for which it's so important, in my case, to test them out?

I'll try this evening anyway.
Old 4 days ago | Show parent
  #1202
Lives for gear
 
🎧 5 years
Quote:
Originally Posted by Starlight ➑️
I used chicken wire stapled to drop ceiling frames so that the insulation could not sag. Here are three photos of how I have done my ceiling.

Your ceiling is being done differently to mine but the principle you mention of using wire to keep the insulation in place is a proven method. It may be too late to get your builder to work differently - stapling chicken wire rather than adding another layer of slats.
I don't want to delay them on this detail, when I know there might be other parts more important on which to insist to proceed differently.
It's strange they didn't think of wire, which is much less expensive.
Old 4 days ago | Show parent
  #1203
Here for the gear
 
Quote:
Originally Posted by FrankDandrea ➑️
Okay, you really want to compare the room to the pure source.

I'm only afraid of volume levels for neighbours. If I pump around 70dB is that sufficient?
How do you want to measure it ?
A sine sweep doesn't last for hours, neither does MLS.

I don't think the neighbors will care much honestly, it's just too short.
Old 4 days ago | Show parent
  #1204
Lives for gear
 
Jason Foi's Avatar
 
🎧 5 years
Quote:
Originally Posted by FrankDandrea ➑️
Okay, you really want to compare the room to the pure source.

I'm only afraid of volume levels for neighbours. If I pump around 70dB is that sufficient?

I'm a bit confused on how testing them in the garden will be beneficial with the firm. Of course it's useful to know how the monitors work in an open space, but the firm guaranteed a certain result in the studio, regardless of how the monitor's sound in an open space. Is there a (maybe obvious) reason for which it's so important, in my case, to test them out?

I'll try this evening anyway.
70db is fine, volume doesnt change FR
Old 4 days ago | Show parent
  #1205
Lives for gear
 
Jason Foi's Avatar
 
🎧 5 years
Quote:
Originally Posted by BogaNet ➑️
How do you want to measure it ?
A sine sweep doesn't last for hours, neither does MLS.

I don't think the neighbors will care much honestly, it's just too short.
Lol, true, they'll just look at eachother and say, "wtf was that!?"
Old 4 days ago | Show parent
  #1206
Lives for gear
 
🎧 5 years
Quote:
Originally Posted by Jason Foi ➑️
Lol, true, they'll just look at eachother and say, "wtf was that!?"
ahahah

well...there could be more sweeps....as I'm still familiarizing with REW.

Anyway, I just tried to lift one. I'm by myself, except for my wife (she usually asks help even to open bottles).
I'll try in some way, but I'm afraid I'll have to wait to test them directly in the room (with the help of workers), before and after flush mount, unless they agree to carry them in the garden, then back in the boxes, then back in the studio....
Old 4 days ago | Show parent
  #1207
Lives for gear
 
avare's Avatar
 
🎧 15 years
Quote:
Originally Posted by FrankDandrea ➑️
ahahah

well...there could be more sweeps....as I'm still familiarizing with REW.

Anyway, I just tried to lift one. I'm by myself, except for my wife (she usually asks help even to open bottles).
I'll try in some way, but I'm afraid I'll have to wait to test them directly in the room (with the help of workers), before and after flush mount, unless they agree to carry them in the garden, then back in the boxes, then back in the studio....
Why back in the boxes? You must have neighbours and/or musician friends willing to help. You could offer studio time in exchange for labour. Use a hand truck like what is used for moving refrigerators, ranges, etc.
Old 4 days ago | Show parent
  #1208
Lives for gear
 
🎧 5 years
Quote:
Originally Posted by avare ➑️
Why back in the boxes? You must have neighbours and/or musician friends willing to help. You could offer studio time in exchange for labour. Use a hand truck like what is used for moving refrigerators, ranges, etc.
Back in the boxes because right now they're still cutting lots of wood and moving lots of dust. The installation of the ATC flush mounted won't be before next week. I'm doing my best trying to find a solution to move the speakers, most of my friends + neighbours are on vacation at the moment, but let's see what I can do of course...

UPDATE ON FLUSH MOUNT DESIGN.

Regarding the flush mount plan, I just received this mail from the firm:

"Here are the details of the supports that we can offer you to install the speakers.
These are dimensioned so as not to have any contact with the existing wood frame (which allows the flat baffle finish to be fixed). The geometry is also reflected in order to leave space for the remote power supply / amplification of each speaker.

The supports would consist of a formwork (made in medium 18 mm) completely filled with sand. Each support will thus weigh 130 kg (+/- 10 kg) without speaker.

We provide a resilient type closed cell foam (PLASTAZOTE brand) to place under the enclosure and thus avoid resonance of the support.

In order to separate the speaker support and the concrete slab, we plan to place a small resilient plate under the 4 feet of the support. For the choice of resilient: two solutions are available to you, each with advantages and disadvantages.

Solution 1
SYLOMER plot, dimensioned in accordance with the weight of the overall support / enclosure system, which would make it possible to obtain a cutoff frequency of 10 Hz.
SYLOMER pads provide us with a cutoff at very low frequencies but two drawbacks exist: these pads are slightly lacking in rigidity and could cause some imbalance when handling the speakers. In addition, these studs are made to measure and delivery times can reach 1 to 2 weeks.

Solution 2
Resilient agglomerated rubber support type plate for industrial machines, available in any store (so no long delivery times) and more rigid than the Sylomers shown above. We would therefore have no concerns about the stability of the supports because of the greater rigidity of the resilient.
The downside for these plots is that we don't have scientific data to calculate the cutoff frequency. We will therefore not be able to provide you with details on this point, but we know from experience that the decoupling carried out by these plates is sufficient and will work in the context of your installation.

I hope that this information will suit you and will allow you to validate the realization of the supports. Do not hesitate to call me tomorrow if you want to discuss the choice of the studs to place under each foot."




On these drawings perhaps it's not clear, but the wood plate on which ATCs will me stand should be a few centimeters over the existing wood framework that they'll use to close the facade, so not to touch it (I hope!).

What do you guys think of this?

They proposed me instead of the pile of cinder blocks, saying this solution is as heavy but easier to move around, if they need to adjust it to fine tune the installation.

I'm reluctant to use method 2 as I prefer Sylomer's scientific data. Although I'm afraid of course that having to wait for the Sylomer to arrive cut delay too much the works, so that they'll have to stop in august and come back to resume in september.
Old 4 days ago | Show parent
  #1209
Lives for gear
 
Jason Foi's Avatar
 
🎧 5 years
Quote:
Originally Posted by FrankDandrea ➑️
Back in the boxes because right now they're still cutting lots of wood and moving lots of dust. The installation of the ATC flush mounted won't be before next week. I'm doing my best trying to find a solution to move the speakers, most of my friends + neighbours are on vacation at the moment, but let's see what I can do of course...

UPDATE ON FLUSH MOUNT DESIGN.

Regarding the flush mount plan, I just received this mail from the firm:

"Here are the details of the supports that we can offer you to install the speakers.
These are dimensioned so as not to have any contact with the existing wood frame (which allows the flat baffle finish to be fixed). The geometry is also reflected in order to leave space for the remote power supply / amplification of each speaker.

The supports would consist of a formwork (made in medium 18 mm) completely filled with sand. Each support will thus weigh 130 kg (+/- 10 kg) without speaker.

We provide a resilient type closed cell foam (PLASTAZOTE brand) to place under the enclosure and thus avoid resonance of the support.

In order to separate the speaker support and the concrete slab, we plan to place a small resilient plate under the 4 feet of the support. For the choice of resilient: two solutions are available to you, each with advantages and disadvantages.

Solution 1
SYLOMER plot, dimensioned in accordance with the weight of the overall support / enclosure system, which would make it possible to obtain a cutoff frequency of 10 Hz.
SYLOMER pads provide us with a cutoff at very low frequencies but two drawbacks exist: these pads are slightly lacking in rigidity and could cause some imbalance when handling the speakers. In addition, these studs are made to measure and delivery times can reach 1 to 2 weeks.

Solution 2
Resilient agglomerated rubber support type plate for industrial machines, available in any store (so no long delivery times) and more rigid than the Sylomers shown above. We would therefore have no concerns about the stability of the supports because of the greater rigidity of the resilient.
The downside for these plots is that we don't have scientific data to calculate the cutoff frequency. We will therefore not be able to provide you with details on this point, but we know from experience that the decoupling carried out by these plates is sufficient and will work in the context of your installation.

I hope that this information will suit you and will allow you to validate the realization of the supports. Do not hesitate to call me tomorrow if you want to discuss the choice of the studs to place under each foot."




On these drawings perhaps it's not clear, but the wood plate on which ATCs will me stand should be a few centimeters over the existing wood framework that they'll use to close the facade, so not to touch it (I hope!).

What do you guys think of this?

They proposed me instead of the pile of cinder blocks, saying this solution is as heavy but easier to move around, if they need to adjust it to fine tune the installation.

I'm reluctant to use method 2 as I prefer Sylomer's scientific data. Although I'm afraid of course that having to wait for the Sylomer to arrive cut delay too much the works, so that they'll have to stop in august and come back to resume in september.
Acoustics 101, only decouple once....

Wtf is plastozote!!?? Searching plastozote speaker decoupling returns no results. Do they have any data backing up their claims that its a suitable material.

Sylomer can dampen/decouple, but i agree, things can get wobly when you do it correctly, hence why everyone, literally ever expert, says you must stabilize on all axis.

Back to the drawing board "experts"...
Old 4 days ago | Show parent
  #1210
Lives for gear
 
DirkB's Avatar
 
🎧 15 years
Well, that would be a mass - spring - mass - spring - mass system in the vertical dimension.

Plus: where is the dampening the the horizontal axis happening? Your speakers are creating forces on the structure they are resting on due to the vibration of the coils. Imagine putting your speakers on 3 lose springs instead of a sturdy stand, what would happen?

Bottom line: this is not a proper design in my view...
Old 3 days ago | Show parent
  #1211
Here for the gear
 
Quote:
Originally Posted by Jason Foi ➑️
Wtf is plastozote!!??
https://www.gwp.co.uk/guides/what-is-plastazote-foam/
Old 3 days ago | Show parent
  #1212
Lives for gear
 
🎧 5 years
Quote:
Originally Posted by DirkB ➑️
Well, that would be a mass - spring - mass - spring - mass system in the vertical dimension.

Plus: where is the dampening the the horizontal axis happening? Your speakers are creating forces on the structure they are resting on due to the vibration of the coils. Imagine putting your speakers on 3 lose springs instead of a sturdy stand, what would happen?

Bottom line: this is not a proper design in my view...
I don't know if that will change your point of view, but they are going to secure the speaker on the MDF/spring plate with a strap, and all above, underneath and all around the speaker there will be rockwool.
Old 3 days ago | Show parent
  #1213
Lives for gear
 
🎧 5 years
Quote:
Originally Posted by Jason Foi ➑️
Acoustics 101, only decouple once....
Is that a strict rule? I remember people here on Gearslutz posting cinder blocks / spring / cinder blocks / spring.....kind of structures.

If I put only one spring, is it better between the speaker and the plate, or between the column and the floor?

Regarding stabilization of monitors on all axis, see my post #1212
Wouldn't strap + rockwool work?
Old 3 days ago | Show parent
  #1214
Lives for gear
 
🎧 10 years
Anyone of the experts care to link to the scientific papers with all the math and measurements on speakers and cabinet motion?
Old 3 days ago | Show parent
  #1215
Lives for gear
 
🎧 5 years
Ready for open air test of ATCs

Ready for open air test of ATCs

Let's hope it's not raining today.



I'll start now the testing. I'll check in here to see if there's any suggestions on how to properly measure speakers.

I'll do one by one then them together. Hope to be able to post first results soon this morning.

What are the most important measurements data to get when speakers are tested open air, by the way? All of them?
Old 3 days ago | Show parent
  #1216
Lives for gear
 
Jason Foi's Avatar
 
🎧 5 years
Quote:
Originally Posted by bert stoltenborg ➑️
Anyone of the experts care to link to the scientific papers with all the math and measurements on speakers and cabinet motion?
Thats the best i got for now....
Freestanding speaker decoupling system DIY on a budget question
Old 3 days ago | Show parent
  #1217
Lives for gear
 
🎧 5 years
Quote:
Originally Posted by Jason Foi ➑️
Thanks Jason.

By the way the firm is willing to use sylomer vs the other material that is not really proven to work (scientifically at least).

For a total 195 kg of load (monitor + structure) he's proposing SYLOMER SR55-25.

Do you think it's a suitable choice, and how many millimiters would you use?
(I don't know if that's an easy calculation but....if anyone knows which sylomer and thickness would work I'd be happy to know.
Old 3 days ago | Show parent
  #1218
Lives for gear
 
🎧 10 years
Quote:
Originally Posted by Jason Foi ➑️
I wonder how much a 65 kg speaker cabinet will rock when excited by a 0.1 kg membrane moving over a couple of mm, don't you? There must be a zilion measurements about that, just like about speaker cables and custom shop solid body guitars .
There were worries in the 1970's about cabinet walls moving as a reaction to driver movement because the middle of the wall, especially when not braced adequate is of course the spot moving most easyly. That is why B&W and other companies created the matrix box.
I sincerely hope a manufacturer daring to ask a ridiculous $ 16.000 for a hifi loudspeaker did take care of that.
Old 3 days ago | Show parent
  #1219
Lives for gear
 
🎧 10 years
Quote:
Originally Posted by FrankDandrea ➑️
Thanks Jason.

By the way the firm is willing to use sylomer vs the other material that is not really proven to work (scientifically at least).

For a total 195 kg of load (monitor + structure) he's proposing SYLOMER SR55-25.

Do you think it's a suitable choice, and how many millimiters would you use?
(I don't know if that's an easy calculation but....if anyone knows which sylomer and thickness would work I'd be happy to know.
Sylomer provides extensive data about all their product varieties making it a piece of cake for an acoustician of a company to calculate this.
Old 3 days ago | Show parent
  #1220
Lives for gear
 
🎧 5 years
Quote:
Originally Posted by bert stoltenborg ➑️
Sylomer provides extensive data about all their product varieties making it a piece of cake for an acoustician of a company to calculate this.
If I read this well, at around 200kg Sylomer SR55-25 decouples even a little bit below 10Hz.

My structure will weight around 195 +/- 10kg. Which means I should be fine?

I remember Northward saying decoupling at 7Hz is advisable as 10Hz is bare minimum. But I think it's not a tragedy if the system really decouples at 10Hz or around that?
Old 3 days ago | Show parent
  #1221
Lives for gear
 
🎧 10 years
Quote:
Originally Posted by FrankDandrea ➑️
If I read this well, at around 200kg Sylomer SR55-25 decouples even a little bit below 10Hz.

My structure will weight around 195 +/- 10kg. Which means I should be fine?

I remember Northward saying decoupling at 7Hz is advisable as 10Hz is bare minimum. But I think it's not a tragedy if the system really decouples at 10Hz or around that?
I don't know, I'd have to calculate that.
But with Sylomer you can float studiobunkers and trainways at 7 Hz, so I wouldn't be surprised.

Edit: I didn't read the northward remark. You get usefull decoupling from SQRT 2 x fs (resonance) so you'll have to decide if 10 Hz is adequate.
Old 3 days ago | Show parent
  #1222
Lives for gear
 
Jason Foi's Avatar
 
🎧 5 years
Quote:
Originally Posted by bert stoltenborg ➑️
I wonder how much a 65 kg speaker cabinet will rock when excited by a 0.1 kg membrane moving over a couple of mm, don't you? There must be a zilion measurements about that, just like about speaker cables and custom shop solid body guitars .
There were worries in the 1970's about cabinet walls moving as a reaction to driver movement because the middle of the wall, especially when not braced adequate is of course the spot moving most easyly. That is why B&W and other companies created the matrix box.
I sincerely hope a manufacturer daring to ask a ridiculous $ 16.000 for a hifi loudspeaker did take care of that.
well, those were my thoughts exactly, and most times i asked i received no response, but I do remember one conversation with thomas where he did give me a range of movement, and it was much more than i thought would be possible. I'll see if i can find the thread.
Old 3 days ago | Show parent
  #1223
Lives for gear
 
Jason Foi's Avatar
 
🎧 5 years
Quote:
Originally Posted by FrankDandrea ➑️
Ready for open air test of ATCs

Let's hope it's not raining today.



I'll start now the testing. I'll check in here to see if there's any suggestions on how to properly measure speakers.

I'll do one by one then them together. Hope to be able to post first results soon this morning.

What are the most important measurements data to get when speakers are tested open air, by the way? All of them?
1m away, mic pointed at acoustical axis of speaker
Old 3 days ago | Show parent
  #1224
Lives for gear
 
🎧 10 years
Quote:
Originally Posted by Jason Foi ➑️
well, those were my thoughts exactly, and most times i asked i received no response, but I do remember one conversation with thomas where he did give me a range of movement, and it was much more than i thought would be possible. I'll see if i can find the thread.
Thomas, although he is the obergruppenhauptsturmbahnfuhrer of this forum, also can be as vague as a 12 year old in the heat at moments :-).
Old 3 days ago | Show parent
  #1225
Here for the gear
 
Quote:
Originally Posted by bert stoltenborg ➑️
Edit: I didn't read the northward remark. You get usefull decoupling from SQRT 2 x fs (resonance) so you'll have to decide if 10 Hz is adequate.
How much useful musical information is present at 14hz ?
Also wouldn't a bass-reflex speaker be high-passed anyway to protect the woofer ?
Old 3 days ago | Show parent
  #1226
Lives for gear
 
🎧 10 years
Quote:
Originally Posted by BogaNet ➑️
How much useful musical information is present at 14hz ?
Also wouldn't a bass-reflex speaker be high-passed anyway to protect the woofer ?
If you can get to 7 Hz with the same efford, why wouldn't you?
Old 3 days ago | Show parent
  #1227
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avare's Avatar
 
🎧 15 years
Quote:
Originally Posted by BogaNet ➑️
How much useful musical information is present at 14hz ?
Also wouldn't a bass-reflex speaker be high-passed anyway to protect the woofer ?
The isolation is 0dB at 14 Hz. If you want 6 dB isolation at 28 Hz, you need the 10 Hz resonance.
Old 3 days ago | Show parent
  #1228
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avare's Avatar
 
🎧 15 years
Quote:
Originally Posted by FrankDandrea ➑️
Ready for open air test of ATCs

Let's hope it's not raining today.



I'll start now the testing. I'll check in here to see if there's any suggestions on how to properly measure speakers.

I'll do one by one then them together. Hope to be able to post first results soon this morning.

What are the most important measurements data to get when speakers are tested open air, by the way? All of them?
Congratulations! The most important is the MLS test. It is like which tire is most important on my car?
Old 3 days ago | Show parent
  #1229
Here for the gear
 
Quote:
Originally Posted by avare ➑️
The isolation is 0dB at 14 Hz. If you want 6 dB isolation at 28 Hz, you need the 10 Hz resonance.
Thanks for the very valid point, I got a bit carried away by bert's point ("you get useful decoupling from sqrt(2)*fs").

Well not really no, it only starts decoupling from that point upward. And possibly relatively slowly one might add :


Although just to be clear, I was not saying there is nothing down there.
I have music CDs with stuff down to 4/5hz, confirmed by both an FFT and a buttkicker LFE.

Now whether one would want to actually reproduce that, with what loudspeaker, and how to isolate it is of course another question.
Old 3 days ago | Show parent
  #1230
Lives for gear
 
🎧 5 years
My acoustician says we don't really need to decouple at 10Hz since my ATC 100's frequency response starts at 32 Hz.

By instinct, my response was: "Isn't going to change after flush mount"?

But he said under 32 Hz will be areal frequencies, and not transmitted as vibration by the monitor support, so that portion under 32Hz doesn't need to be decoupled.

Comments on that?

(By the way he says he's willing to use one layer only of Sylomer SR-55, the load distributed over 4 small plots 20mm thick.

PS: I finished measurements, I'll post them soon.
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