Small music writing and mixingroom

[Soundman2020]

The listening position is now 43% /

That's getting a little far back in the room... I'd try to bring it forward a bit. Maybe tighten the angle of the soffits just a bit.

I also noticed that you have a 30cm depth from the wall to the "panel" between your soffits: is that necessary? Could you get by with less than 30cm, and still fit in your speakers, framing, damping, and ventilation? If so, then consider reducing that distance.

Also, what is your plan for that "panel"? Will that be something solid, rigid, and massive? Or soft? Will it run from floor to ceiling? If it large, solid, massive, and full height, then it's going to change the acoustic length of the room, and modify the modal behavior...

hAlso, Have you thought about how to mount your 8330s in the soffits? It's not easy to do, due to the strange shape...

- Stuart -

[MattHank]

Thanks for your response Stuart!

That's getting a little far back in the room... I'd try to bring it forward a bit. Maybe tighten the angle of the soffits just a bit.

Do you mean a bigger angle, like something over 30°? What is a good distance of speaker beams from my ears at mixing position?

I also noticed that you have a 30cm depth from the wall to the "panel" between your soffits: is that necessary? Could you get by with less than 30cm, and still fit in your speakers, framing, damping, and ventilation? If so, then consider reducing that distance.

I'll try if I can make it less than that. I just wanted to leave enough space for the speaker box and for a possible future speaker update.

Also, what is your plan for that "panel"? Will that be something solid, rigid, and massive? Or soft? Will it run from floor to ceiling? If it large, solid, massive, and full height, then it's going to change the acoustic length of the room, and modify the modal behavior...

I will do it like Frank's/John's soffit. So there's a 30cm gap at the bottom and that hard-backed insulation part for desk reflections above that. Also a gap at the top part of the soffit. I was thinking I could use mdf at the front, maybe two or three layers of 19mm. But a thick soffit face will also make mounting of my monitors more difficult. Are the side wing faces also meant to be as massive and rigid? If this all also changes the acoustic lenght of the room, how do I need to take this in consideration? Should I count my mixing postion 38% from the middle part between the soffits?

Also, Have you thought about how to mount your 8330s in the soffits? It's not easy to do, due to the strange shape...

Yeah, that's a problem. But there are screw holes at the back of the speaker. I could make a similar L-shaped steel part that Genelec uses to secure the speaker to their soffit mount box. Then I could mount the speaker tightly in a rigid mdf box with that steel part, so that the speaker won't move at all and so that it comes out of the box enough. It would be very difficult to make the speaker itself floating. But could this box around the speaker be decoupled from the soffit structure? Or could I just attach the box tightly to the shelf?

genelec_8330a_back.jpg

Genelec flush mount kit 1.png

genelec flush mount kit 2.png

[Waka]

Hi Matt,

I might be able to help.

Do you mean a bigger angle, like something over 30°? What is a good distance of speaker beams from my ears at mixing position?

Stuart is talking about reducing the internal angles of a triangle created by connecting the two speakers and the listening position.
Currently they are 30 degrees inwards from pointing straight down the length of the room. This is 60 degree internal angle. If you "tighten" this angle to 55 degrees for example (giving you 35 degrees off pointing straight down the room) you will bring the listening position closer to the front wall. Increasing the angle from 30 towards 45 degrees narrows the sweet spot, but can widen the sound stage.

I'll try if I can make it less than that. I just wanted to leave enough space for the speaker box and for a possible future speaker update.

Increasing the angle of your speakers from 30degrees may help with this also as they will project towards the corner more.

I will do it like Frank's/John's soffit. So there's a 30cm gap at the bottom and that hard-backed insulation part for desk reflections above that. Also a gap at the top part of the soffit. I was thinking I could use mdf at the front, maybe two or three layers of 19mm. But a thick soffit face will also make mounting of my monitors more difficult. Are the side wing faces also meant to be as massive and rigid? If this all also changes the acoustic lenght of the room, how do I need to take this in consideration? Should I count my mixing postion 38% from the middle part between the soffits?

If the middle part is massive, like the baffles then count the mix position from this, yes.

Yeah, that's a problem. But there are screw holes at the back of the speaker. I could make a similar L-shaped steel part that Genelec uses to secure the speaker to their soffit mount box. Then I could mount the speaker tightly in a rigid mdf box with that steel part, so that the speaker won't move at all and so that it comes out of the box enough. It would be very difficult to make the speaker itself floating. But could this box around the speaker be decoupled from the soffit structure? Or could I just attach the box tightly to the shelf?

genelec_8330a_back.jpg

Genelec flush mount kit 1.png

genelec flush mount kit 2.png

For the speakers you will prob be better floating them within a heavy box with sorbathane. Then cutting the front baffle to fit the shape closely. You could mount them like you say, but they might transfer vibration into the structure. Unless you can mount the brackets in a way that decouples them, using sorbathane washers/bushings.

Dan

[MattHank]

V4 here

RFZ V4.jpg

[Gregwor]

V4 here

Greg

[Soundman2020]

Looking good! Time to start building your SketchUp model, and check it out in 3D....


- Stuart -

[MattHank]

Looking good! Time to start building your SketchUp model, and check it out in 3D....

Great! I'm working on it!

[MattHank]

What do you think, is this enough mass for the soffit face: 19mm mdf - 3mm mlv - 19mm mdf? Frank's soffit face looks similar to that. Do I also need to make the sidewings like that?

[Soundman2020]

is this enough mass for the soffit face: 19mm mdf - 3mm mlv - 19mm mdf?

Sounds about right, yes.

Do I also need to make the sidewings like that?

Perhaps! The design of the soffit "wings" can be done in several ways, but in this case, the "wings" are actually sliding glass doors to other rooms!

- Stuart -

[MattHank]

I had 3 days sick leave and had time to start learning SketchUp. At first I thought it's too difficult to learn, but after I watched some tutorials on youtube, I started to get it. Now I think it's totally true when people say that you should design your studio first in 3D, it's much easier to make changes in your drawing and you can spot your mistakes before you build. And you can easily calculate the amount of building material needed. Here's my soffit design. I'm not sure if I should put hangers in the upper part of the soffit or just make it superchunk.

Soffit 1.jpg

Soffit 2.jpg

Soffit 4.jpg

Hanger on the right side is 40cm wide and the shortest is 10cm. I couldn't make them any wider. If those need to be wider, then I need to bring the soffit front more towards back of the room.

Lower hangers.jpg

Here's my idea for mounting the speaker to the box. There's a metal bracket attached to the speaker with two 6mm screws. Then a bolt attached to the mdf box, with sorbothane washers and bushings, to make sure the speaker stays in place. I haven't calculated those sorbothane pads yet, but in the picture they are 50mm wide and 25mm high. There's a 6cm empty space behind the speaker in the box.

Speaker box2.jpg

Speaker.jpg

[Gregwor]

Great work!

Did you consider putting some sorbothane under the speaker box bottom plate to decouple the entire speaker module from the soffit?

Greg

[MattHank]

Thanks Greg! Yeah, I was thinking about it. I could draw that too.

[Soundman2020]

Did you consider putting some sorbothane under the speaker box bottom plate to decouple the entire speaker module from the soffit?

You CAN do that, if you are careful, but do beware: that makes it into the equivalent of a 3-leaf system: You have Mass (the speaker) - Spring (the rubber between the speaker and the box) - Mass (the enclosure box) - Spring (the rubber under the box) - Mass (the entire soffit structure. So it is MSMSM: a three-leaf system. Therefore, you have to use the equations for 3-leaf systems to do the calculations here, to ensure that your f- and f+ are BOTH still well outside the range where that system won't be isolating...

Things are not always what they seem at first sight. You think "If isolating it once is good, then isolating it twice must be better!". Not always true... only if you specifically design it to be so...

- Stuart -

[Waka]

So it is MSMSM: a three-leaf system. Therefore, you have to use the equations for 3-leaf systems to do the calculations here, to ensure that your f- and f+ are BOTH still well outside the range where that system won't be isolating...
- Stuart -

Hi Stuart, that's very interesting. Can I ask which formulae you use for your 3 leaf systems? I'm struggling to find a good one.

Dan

[Gregwor]

Hi Stuart, that's very interesting. Can I ask which formulae you use for your 3 leaf systems? I'm struggling to find a good one.

Check out page 342 of Architectural Acoustics by Marshall Long

Greg