Soft Flush mount specs

How thick should my walls be, should I float my floors (and if so, how), why is two leaf mass-air-mass design important, etc.

Moderators: Aaronw, sharward

Soundman2020
Site Admin
Posts: 11938
Joined: Thu Aug 21, 2008 10:17 am
Location: Santiago, Chile
Contact:

Re: Soft Flush mount specs

Post by Soundman2020 »

Don't confuse raytracing with raytracing! :)

There's two very different things that both use the same word. One of those is a video rendering technique that can produce very high quality photo-realistic images, with real lighting, shadows, reflections, textures, etc. That's not what you want. That's the plugin you got, but that's not what you need.

The other type of raytracing, you do by hand, one painstaking step at a time. Long, slow, boring process, but the only way to check that your room is acoustically sound. You do this type of tracing by drawing out many "rays" that leave the acoustic center of your speaker, at many angles, and seeing where each ray goes: what surfaces in the room does it hit. When a ray hits a surface, you make it "bounce" by drawing the reflected version of that ray, as though the surface was a mirror and the original ray was a laser beam hitting it. So the angle of reflection is equal to the angle of incidence, but flipped over in the opposite direction.

You do that with a whole bunch of rays leaving your speaker at small intervals, such as every 5°, or every 10°, in both directions. After you have done a few dozen of those, you'll be able to get a picture of where the sound is going in your room, what surfaces it is hitting, and where the reflections from those surfaces are going.

After you have done that in the horizontal plane, you then also do it in the vertical plane, because sound is 3D not 2D.

Like I said: very slow, boring, painful, maddening process. It would be nice if there was a plugin to do this type of raytracing for you, but there isn't...

The "picture" can end up looking something like this:
RDMS-V285-RayTrace-example.png
Another way that I've developed to help with this, is a geometric component with colored segments at 5° increments, that I just attach to the acoustic axis of the speaker. It helps to get a quick idea of hos things are working out, and I then use it as the basis for ray-tracing:
Rainbow-raytrace.png

- Stuart -
matt-korban
Posts: 29
Joined: Sun Oct 21, 2018 2:19 am
Location: Sardinia - Italy

Re: Soft Flush mount specs

Post by matt-korban »

Ok, i got it.
How much i have to consider for speaker sound irradiation in degrees? 60, 90, 100?
The speakers are Amphione One 18.
matt-korban
Posts: 29
Joined: Sun Oct 21, 2018 2:19 am
Location: Sardinia - Italy

Re: Soft Flush mount specs

Post by matt-korban »

Guys some help?
How much i have to consider for speaker sound irradiation in degrees? 60, 90, 100?
- You should have a back on your speaker enclosure. Leave a hole in it to pass heat and cabling.
Maybe i can not do that... my monitor have a back passive radiator, and i don't know if i can cover it with cabinet...
- What are you using for your soffit baffle?
I think 26mm of drywall, because large and big wood panels here in italy cost really much...

Here you can see some progress of sketchup project... Maybe this can be a solution?
One reflection don't bounce because hit a fiberglass triangle absorber... what do you think?
Raytracing 1.jpg
Soundman2020
Site Admin
Posts: 11938
Joined: Thu Aug 21, 2008 10:17 am
Location: Santiago, Chile
Contact:

Re: Soft Flush mount specs

Post by Soundman2020 »

How much i have to consider for speaker sound irradiation in degrees? 60, 90, 100?
What speakers are you using? What is their dispersion like? What frequencies fall off at what angles? What treatment would you need at each angle to deal with the remaining frequencies?

It's all about directivity. Check the directivity plot for YOUR speakers, and compare that to YOUR room...
Maybe i can not do that... my monitor have a back passive radiator, and i don't know if i can cover it with cabinet...
Of course you can! If you build the enclosure correctly. The speaker won't blow up or burn out if you soffit-mount it. Take a look at this thread (click here) and note the speakers. Those are Eve Audio SC-407s. They have a massively huge bass reflex port on the back, yet there they are, mounted in soffit, with an massive enclosure box around them on all sides except the front, and the seem to be performing rather well like that... :) Why would yours be different? A passive radiator is basically the same as a bass reflex port, just implemented in the form of a damped speaker cone, instead of a tuned tube. It still moves air in roughly the same way as a port, except that it avoids some of the pitfalls of reflex ports. But as far as the soffit is concerned, it's pretty much the same...
I think 26mm of drywall, because large and big wood panels here in italy cost really much...
Not drywall, no. You have to cur a large hole in the baffle for the speaker to go through, and you can't do that with drywall: the edges would be brittle, flaky, and pumping out powdered gypsum all the time, from the pressure changes inside the soffit. Use something like MDF, OSB, or plywood. It needs to be heavy, thick, and rigid.
One reflection don't bounce because hit a fiberglass triangle absorber... what do you think?
That won't work. That discontinuity in the baffle where the fiberglass is, will create all types of artifacts. You should angle the soffit "wings" more, as well, such that the reflections go a long way behind your head.

Also, you are only drawing rays on ONE side of the speaker: it emits sound in BOTH directions... :)



- Stuart -
matt-korban
Posts: 29
Joined: Sun Oct 21, 2018 2:19 am
Location: Sardinia - Italy

Re: Soft Flush mount specs

Post by matt-korban »

What speakers are you using? What is their dispersion like? What frequencies fall off at what angles? What treatment would you need at each angle to deal with the remaining frequencies?

It's all about directivity. Check the directivity plot for YOUR speakers, and compare that to YOUR room...
Ok i have send a message to the tech support that will tell me something about speaker irradiation...

Of course you can! If you build the enclosure correctly. The speaker won't blow up or burn out if you soffit-mount it. Take a look at this thread (click here) and note the speakers. Those are Eve Audio SC-407s. They have a massively huge bass reflex port on the back, yet there they are, mounted in soffit, with an massive enclosure box around them on all sides except the front, and the seem to be performing rather well like that... :) Why would yours be different? A passive radiator is basically the same as a bass reflex port, just implemented in the form of a damped speaker cone, instead of a tuned tube. It still moves air in roughly the same way as a port, except that it avoids some of the pitfalls of reflex ports. But as far as the soffit is concerned, it's pretty much the same...
Ok i'll try to do that!

That won't work. That discontinuity in the baffle where the fiberglass is, will create all types of artifacts. You should angle the soffit "wings" more, as well, such that the reflections go a long way behind your head.
Ok, i have modified something...
- Speaker moved just 15cm to the front center wall
- "Sides baffle wings" more angled (in the picture there is not window, but i'll put soon in the project (same angle of the wall)

- This appear a nice RFZ (in the horizontal plane), what do you think?
- Is there some problem if i build with MDF only the speaker wall baffle and build with drywall front center baffle and sides baffles?
- What do you think about the rear wall broadband absorber, with the corner? (it's covered with some tipe of fabric)
Raytracing Modified room 1.jpg
Raytracing Modified room 2.jpg
Raytracing Modified room 3.jpg
Raytracing Modified room 4.jpg
Also, you are only drawing rays on ONE side of the speaker: it emits sound in BOTH directions... :)
:D yes i know, just trying...
Soundman2020
Site Admin
Posts: 11938
Joined: Thu Aug 21, 2008 10:17 am
Location: Santiago, Chile
Contact:

Re: Soft Flush mount specs

Post by Soundman2020 »

You still are not tracing rays out far enough, in either direction. You are doing maybe 40° or 45°. Take a closer look at the examples I gave you. I'm pretty sure you have first reflection issues on your side walls.

Also, you have a skyline diffuser on the rear wall: I doubt that your studio is large enough to do that successfully. What frequency range will you tune the skyline for, and what is the distance from the front of the skyline to your ears?

- Stuart -
matt-korban
Posts: 29
Joined: Sun Oct 21, 2018 2:19 am
Location: Sardinia - Italy

Re: Soft Flush mount specs

Post by matt-korban »

I'm doing 50 degree for each side, 100 in total...

I'll tune the skyline (or maybe other tipe of diffuser, you can suggest me) maybe around 1khz...
I have read your post (and something about Alton Everest) about the time for return the reflection at hears, after at least 20ms for avoid problems...

For a directly and clear reflection, from the speaker to the rear wall (or diffuser), and from the rear wall to listening point (speaker/rear/listening point) i have about 797cm...
So something like 23ms at 20 celsius... maybe good?

The skyline (or other diffuser) / listening point distance is 320 cm.
matt-korban
Posts: 29
Joined: Sun Oct 21, 2018 2:19 am
Location: Sardinia - Italy

Re: Soft Flush mount specs

Post by matt-korban »

I have modify at 120 degrees the irradiation of the speaker...

Here the result, what do you think?
Soundman2020
Site Admin
Posts: 11938
Joined: Thu Aug 21, 2008 10:17 am
Location: Santiago, Chile
Contact:

Re: Soft Flush mount specs

Post by Soundman2020 »

That's not 120° !!!

0° is straight ahead. 90° is straight out to the side, along the face of the speaker. 120° would be going BACKWARDS, behind the speaker, into the wall...

Take another look at what I posted earlier:
Rainbow-raytrace.png
Look at the numbers....

- Stuart -
Paulus87
Senior Member
Posts: 652
Joined: Sun Mar 02, 2014 8:42 am
Location: Wales, UK

Re: Soft Flush mount specs

Post by Paulus87 »

I think you could get a much bigger RFZ by decreasing the length of your soffit wings and increasing the angle at which they splay out. In my experience the length of the soffit wings only needs to extend as far as the listening position (imagine there’s a horizontal line going through your ears to your side walls) that’s about as far as is needed to make it decent... of course I can only speak from experience designing my own RFZ and the dimensions are different to yours... but try it. In my opinion it’s better for the sweet spot to be wider rather than longer as you’ll be mainly moving from side to side as you mix to get to your hardware.

Paul
Paul
matt-korban
Posts: 29
Joined: Sun Oct 21, 2018 2:19 am
Location: Sardinia - Italy

Re: Soft Flush mount specs

Post by matt-korban »

Ok ok now i got it! Sorry.

See below and let me know...

I have considered 80 degrees for each side.
Raytracing 120 1.jpg
Raytracing 120 2.jpg
Raytracing 120 4.jpg
Soundman2020
Site Admin
Posts: 11938
Joined: Thu Aug 21, 2008 10:17 am
Location: Santiago, Chile
Contact:

Re: Soft Flush mount specs

Post by Soundman2020 »

See below and let me know...
:thu:

Yup!


- Stuart -
matt-korban
Posts: 29
Joined: Sun Oct 21, 2018 2:19 am
Location: Sardinia - Italy

Re: Soft Flush mount specs

Post by matt-korban »

So i have my RFZ room? :D
Now i can proceed and start building?

If you tell me that's ok, i add to my project the window, and the inspection hatch, for let me know if it's everything ok...
Ok?
matt-korban
Posts: 29
Joined: Sun Oct 21, 2018 2:19 am
Location: Sardinia - Italy

Re: Soft Flush mount specs

Post by matt-korban »

Here an idea for the inspection hatches...
A cutted piece of the same wood used for the baffles (maybe MDF), screwed up and maybe also with rubber gasket at the baffle wood stud structure...

You think it's ok? This don't will cause some tipe of artifact?
Soundman2020
Site Admin
Posts: 11938
Joined: Thu Aug 21, 2008 10:17 am
Location: Santiago, Chile
Contact:

Re: Soft Flush mount specs

Post by Soundman2020 »

Why do you need inspection hatches? You will never be able to get to anything back there, because the massive bass trapping under the speaker shelf will be in your way. One the soffit is completed properly, you will never be able to get to anything under there, ever again.

If you have anything that needs inspecting back there, then move it to the MIDDLE of the front wall, in between the soffits, where it will be much easier to access.

Take a close look at the soffit construction on other threads, to understand this.


- Stuart -
Post Reply