SIMO Studio - Construction Phase

[Soundman2020]

I managed to find a supplier for Sorbothane here in the UK… wow! that stuff IS expensive:

Yeah, but it's the best stuff for isolating speakers. Neoprene and EDPM are the next best, I think. Some types of foam will work too, but the key is to make sure that what you use actually does isolate! Just like for a floating floor, you need to get the right amount of compression of the rubber / foam / whatever. The basic principle is the same: it acts as a damped spring, to decouple. If it is not compressed enough, it doesn't act as a spring, so no isolation. If it is over-compressed, same problem. It needs to be compressed the right amount under the weight of your speaker and/or the mounting method. So yes, some foams will work, as well some types of rubber, but it has to be done right.

How thick does it have to be? Same answer! Thick enough to isolate when compressed the right amount... that depends on the characteristics of the rubber / foam, the weight of your speaker, etc. The best thing to do is to get the data from the manufacturer: see how much weight you need per unit area to compress it the right percentage. If you can't find the data, get a sample of the rubber and test it yourself: measure the amount of deflection for several different loads.

- Stuart -

[simo]

Gotcha Stuart, thanks a lot for that !

…Right... on the electrics now:

I've got an electrician coming tomorrow to start wiring my studio.
He has never wired a studio before - or anything that should categorically be noise free - so I'm fighting a bit to convince him about the need of a proper earthing (star earthing).

Just to make sure I understand the concept (be aware that my knowledge in electronics is near to none!) before trying to explaining it to him and win the battle, I prepared a quick sketch of how I believe it should be:

Studio Electrics.pdf

Is that it? Am I missing something?
Also, Are there any other considerations on the house service panel, from where the studio main panel is getting the power from?

ciao
Simo

[BriHar]

The House Service panel should already be earthed with a rod - you should not need to drive another extra rod (in fact you might find this is prohibited in your local codes) ! Star grounding is about relative potential not absolute ground.

The cable from your service entry to your studio panel is a bit overkill at 16mm² (we are refering to the conductor cross-section) 3 - 5 mm should be sufficient - you've got 4 circuits typically rated at 15 A each (maybe you want 30 for HVAC and Equipment - although for equipment I would divide this into 2 15A circuits - but lighting shouldn't require more than a 10A. In any case your electrician has to know what's required here - that's part of his job!

Your note in red specifies three-phase cable - I think you mean 3 conductor cable and typically LNPE 3 x 1.5mm², again your electrician must know this. More important would be to specify whether these cables are in the wall, on surface and with or without conduit.

Your star-grounding scheme is correct though the Ground will be tied to the service earth as opposed to a separate rod as mentioned above. The 'separated junction box' is usually called a potential ground and consists of a copper terminal strip with a cover - not an actual box per-se, often will be mounted in or beside the sub-panel.
A separate conduit for the ground wires is not absolutely necessary, but I suggest the gauge of the ground wires should be higher than the power conductors typically 2.5mm² if the other conductors are 1.5mm².

Another thing to consider is you may want to route all power cabling near to the floor and have all signal and audio cabling near (or in) the ceiling, making sure that cables for lights etc. (in the ceiling) cross audio/signal cables at right angles.

[simo]

Thanks so much for your help Brian, much appreciated !!

The House Service panel should already be earthed with a rod - you should not need to drive another extra rod (in fact you might find this is prohibited in your local codes) !

Yes the House Service panel is earthed with a rod in the ground under the floor boards. Ok, I'll scrap the idea of the additional rod

The cable from your service entry to your studio panel is a bit overkill at 16mm²

I thought so… I've just been adviced to use that by a different electrician when building the outside construction.

IMG00143-20100409-1253.jpg

IMG00144-20100409-1253.jpg

Your note in red specifies three-phase cable - I think you mean 3 conductor cable and typically LNPE 3 x 1.5mm²

Sorry, accordingly with his quote he's using 2.5mm² twin and earth cable.

More important would be to specify whether these cables are in the wall, on surface and with or without conduit.

They run through (and are clipped to) the studwork, not in a conduit.

Your star-grounding scheme is correct though the Ground will be tied to the service earth as opposed to a separate rod as mentioned above.

Ok, is this updated star-grounding scheme better?

Studio Electrics-2.pdf

A separate conduit for the ground wires is not absolutely necessary, but I suggest the gauge of the ground wires should be higher than the power conductors typically 2.5mm² if the other conductors are 1.5mm².

So, if the 3 conductor cable he's using is 2.5mm², should the gauge of the ground wires be 3.5mm² (quite big) or 2.5mm² would be ok?

Another thing to consider is you may want to route all power cabling near to the floor and have all signal and audio cabling near (or in) the ceiling, making sure that cables for lights etc. (in the ceiling) cross audio/signal cables at right angles.

Yes, I'll pay attention to that - thanks for reminding me though


ciao
simo

[BriHar]

I'm not sure what's planned here. It looks like your Electrician is branching 3 phases to the out-building (or is it 2 phases and neutral?)- I had assumed a sub panel off the main panel but in this case it is being treated as a separate service i.e. parallel (split after the meter), in which case the original grounding scheme may indeed be correct particularly if the neutral has to be spearately established. I had forgotten that we're dealing with an out building here, so double check with your local code and electrician, this has more to do with regulations and safety. Sorry if I threw you a curve here.

2.5mm² being specified for your circuits then I assume your branches are 25 or 30A - OK though the lighting really only should need 14 or 15A in which case 3x1.5mm² would be sufficient (cheaper!) (these circuits of course require no separate ground wires)
The grounding wires should never be less diameter than the L & N wires so above 2.5mm² as long as they match it will be ok. The larger gauge the wire, the less resistance, which is why I recommend the largest wire possible for the earthing - but agreed, above 2.5mm² the need diminishes. In my own case I have a 3.5mm² copper wire running from the service to my PE bus, from there I starground each outlet with 2.5mm² - the power wiring is 1.5mm²

If indeed you have more than a single phase then ensuring that your Audio equipment is on a separate phase to the others (esp. HVAC) I'm sure is being considered, consider too though what loads are on what phases in the main house as well.

I'm just going on assumptions so if you can provide more detail on the actual planning, this would be a great help, and reduce the possibility of false assumptions.

[BriHar]

By the way, while we're on the topic of grounding, something else you might consider ...

Many of todays effects and audio gear are powered via adapters - wallwarts. As such these devices have no grounding and are simply floating. Under some configurations these too can cause ground loops and sometimes need to be grounded. So you might want to provide near (some of) your receptacles, a binding post or banana jack tied directly to ground (because of proximity these can be tied to the local receptacle ground).
Case in point: Sometimes I digitize vinyl records - recording, cleaning, and burning onto CD. I plug my turntable into a small soundcraft mixer (because this has a built-in RIAA filter). The turntable (as many do) has and requires an additional ground wire (otherwise it hums). The mixer which has a grounding binding post on the side just for this eventuality, is powered by a wallwart so there is no real grounding at the mixer. If I go directly to an amp, usually the grounding over this path is sufficient, but if I route through my main mixer and into my PC the hum is evident. So I've included a green banana socket mounted on the panel where I usually power the Turntable and I simply plug a wire between the small mixer's ground lug (which also accepts a banana jack) and this socket - problem solved.

FWIW

[simo]

Thanks for your input Brian, very helpful indeed!

I've just emailed my electrician, so hopefully I should be able to make it a bit clearer very soon.

Great tip the banana jack tied directly to ground…I do use turntables too so that option could be handy.

ciao
simo

[simo]

...Ok this is what my electrician told me:

It looks like your Electrician is branching 3 phases to the out-building (or is it 2 phases and neutral?)

It's Single Phase (1 Live, 1 Neutral, 1 Earth)

I had assumed a sub panel off the main panel but in this case it is being treated as a separate service i.e. parallel (split after the meter), in which case the original grounding scheme may indeed be correct particularly if the neutral has to be spearately established.

It's split off Hanley block from Main Supply (small garage board in house and Main board in studio).

2.5mm² being specified for your circuits then I assume your branches are 25 or 30A

Lighting (6 Amp), 2 x Ring circuit (32 A)

Hope it makes sense

ciao
simo

[BriHar]

Single phase, two would be preferable (isolation of audio circuits a described earlier) but perhaps you only have the 1 phase available. Still, I wonder the 16mm² wiring - do you mean 16mm² cable (i.e. containing all 3 conductors)? OK I checked, in the UK this is apparently the diameter of the whole cable - OK.

It's split off Hanley block from Main Supply (small garage board in house and Main board in studio).

Terminology problem here, never heard of a Hanley Block, you refer to 'main supply' and 'main board' then 'garage board',and that being in house while 'main board' is in studio ... now I'm really getting disoriented.

Regardless, as I now understand it Somewhere the power is delivered to your property, and this then goes to a meter from whence it is fed to the buss bars (Hanley block?) of your distribution panel. Here too, the Neutral and ground buss are bonded to a rod driven into the ground in the near vicinity. From this Panel your (16mm²) 3 conductor cable is attached directly to the hot, neutral and ground busses, and this cable goes to your distribution panel in the studio.

The main point of this was simply to determine the necessity of a separate ground rod. Regardless where what panel is, the description of your service shows that a separate ground rod is not required.

Again, star-grounding is all about potential - a common grounding, potential reference for all devices and gear in the studio. Exactly where it physically bonds to the grounding rod is not so important - but also why I recommend the heaviest gauge wire for this connection as is feasible.

[simo]

Hi there,

Here is the updated drawing of the electrics for my studio:

SIMO Studio Electrics.pdf

Brian, I hope I can answer your questions with that
…but, quickly:

I wonder the 16mm² wiring - do you mean 16mm² cable (i.e. containing all 3 conductors)?

Yes, it's a 16mm² SWA (Steel Wired Armoured) cable containing all three conductors.

Terminology problem here, never heard of a Hanley Block, you refer to 'main supply' and 'main board' then 'garage board',and that being in house while 'main board' is in studio ... now I'm really getting disoriented.

What they call Henley Block here is a junction box (essentially a splitter).
The small consumer unit in the house, what he call "garage board" (after the henley block), which has it's own main switch and a 50A circuit breaker, is there to avoid that if something trips in the house (washing machine, fridge, etc..) it won't affect the studio.

The main point of this was simply to determine the necessity of a separate ground rod. Regardless where what panel is, the description of your service shows that a separate ground rod is not required.

For what he told me, actually there isn't a rod into the ground in the house. He said that here in UK the rod is outside (before entering the property) and so it comes in already 'earthed' (this is different for houses in the countryside and/or for out buildings). And that's why he was suggesting to have a separated rod for the studio.
Hope that makes a bit more sense…(?!)

Please let me know if I'm missing something?

Many Thanks
ciao
Simo

[simo]

Hi there all,

I'm presently enquiring about HVAC systems as I can't postpone it any longer and so should be the next step in my build.

So far I've received three quotes from companies that have experience in HVAC system for studios. The result is that they all are WAY too expensive for my pocket, so I need to think of alternatives.

Comparing these quotes, one common point is that all of them opted to install one SPLIT ducted heat-pump A/C system per room (1 x 5kw for the control room and 1 x 3.5kw for the live room), with ducting and in-ceiling attenuators plus a fresh air system.

In my studio, the option of installing a SPLIT HVAC system becomes unsuitable as the void between the outer and inner ceiling is minimal (only 35 cm). This makes it very difficult to fit the fan coil unit in such a small space.
For this reason I was considering to install a MINI-SPLIT AC system instead (one per room), and provide Fresh air through a separated ducting system. That should be sufficient, right?

Since my understanding of  HVAC is very limited (just about the same as my knowledge of electrical systems ) I was wondering whether you could check if the following is correct:
From what I understand a MINI-split system does not have any ducting at all, as the only connections between the outdoor unit (Compressor) and the indoor wall mount unit is a Refrigerant and an Electricity piping connection.

So the question is : Using this approach, do I need to use the ducting (with silencers) JUST on the system providing fresh air in and exhausting stale air out (as it's the only connection with the outside world)? or I'm missing something?

Also, being that the fresh air supply is not connected to the AC system (or at least I don't see how it could be done?!), does this mean that it won't be possible to condition the fresh air (heat it or cool it down)?

Any help to clarify this issue is much appreciated !!

Many Thanks


ciao
Simo

[Soundman2020]

For this reason I was considering to install a MINI-SPLIT AC system instead (one per room), and provide Fresh air through a separated ducting system. That should be sufficient, right?

Yup! That will work just fine.

From what I understand a MINI-split system does not have any ducting at all, as the only connections between the outdoor unit (Compressor) and the indoor wall mount unit is a Refrigerant and an Electricity piping connection.

Exactly. Normally there are two pipes and one electrical cable.

So the question is: Using this approach, do I need to use the ducting (with silencers) JUST on the system providing fresh air in and exhausting stale air out (as it's the only connection with the outside world)? or I'm missing something?

Exactly. You'll need two silencers per room, one on the incoming fresh air duct, and one on the outgoing stale air duct.

Also, being that the fresh air supply is not connected to the AC system (or at least I don't see how it could be done?!), does this mean that it won't be possible to condition the fresh air (heat it or cool it down)?

That depends on how you route your incoming fresh air! If you arrange things so that the register on the end of the fresh air duct is right next to the intake grill on the mini-split, aimed right at it, then most of the fresh air will get sucked straight in to the unit, and be conditioned before it goes into the room.

In that case, you should have the intake register for the stale air duct on the other side of the room, hopefully high up, where the hottest and "stalest" air will be in the room, near the ceiling (or in the ceiling), and as far as possible from the inlet/mini-split, in order to not suck out and throw away air that has just been brought in, cooled and de-humidifed. So try to put those exhaust ducts where the hottest, dirtiest air will be in the room.

You will still need fans in all of the inlet/exhaust ducts, to move the fresh/stale air into and out of the rooms. Those fans need to be sized correctly to move the right amount of air for each room (CFM / room changes per hour, or whatever else you calculated).


- Stuart -

[simo]

Stuart - Thanks so much for your advice man, Very kind and very informative as usual !!

I'll make a sketch as soon as I can and will post it to see if I'm on the right track.


Grazie !
Simo

[simo]

Hiya !

Here is a sketch of how I was thinking of doing the fresh air in / stale air out system - hope you can follow it.
I made it just for the control room, but obviously the idea applies to the live room as well.
I've got a few questions BUT let me check first if I'm on the right track, just to avoid wasting mine and your time

Any advice or suggestions always very welcome!

Simo Studio Fresh Air system 1.jpg

Simo Studio Fresh Air system 2.jpg

Simo Studio Fresh Air system 3.jpg

Simo Studio Fresh Air system 4.jpg

Simo Studio Fresh Air system 5.jpg

Simo Studio Fresh Air system 6.jpg

ciao
Simo

[Soundman2020]

The air plan looks fine to me, but I'm wondering why your "main studio ceiling frame" does not go all the way to the rear wall and the front corners! The frame only goes as far as the front of the soffits and the edge of the rear bass traps. ???


- Stuart -