SIMO Studio - Construction Phase

Wow! Excellent work Simo and I don't think you could ever have enough pics. Very helpful. We're you a carpenter before you started this build? If not, you sure are one now. Keep it up. I'm sure I'm not the only one here living vicariously thru your build until I have the chance to build my own studio. Charlie

Hello everyone, hope all is well ! Charlie -> sorry I missed your post..thanks a lot for your encouragement man- it means a lot. you are very kind! No, actually I've never cut wood before, this is my first time :-) I just religiously followed this forum and tried to apply what I could see, the rest I guess is just desire to have my own space (which who knows if it will ever see the finishing line?!) :-) Have you started your build? Have you opened a thread? I finished the framing for the live room ceiling. Next electrics and HVAC (dreading it!) Ciao! simo

Simo - I am not staying in the house I am currently in and since mine will be a personal studio only, I want to make sure it's a permanent situation before I build anything. In the meantime I'm just learning as much as I can from this forum. Keep the updates coming. Fabulous! -Charlie

Charlie - good luck with your planning & researching stage then ! Looking forward to see your construction thread appearing on this forum very soon :thu: ciao simo

Hi there, A couple of questions about bass trapping: These are the two spaces I built at the rear of my control room to house acoustic hangers I'm planning of using a 3mm plywood for the core, and 50mm insulation on the sides Following the distance recommended on John's design, i.e.150-200mm (I assume not from the center of the hangers but from its edge, well not a huge difference anyway), I measured that I would manage to place just three of them in there! It seems a bit of a waste of space to me, what do you think? … Actually I never heard them in action so I don't know if three hangers in each side at the rear will be enough? Would it be better to have a big superchunk instead? or perhaps a combination of the two, i.e. superchunk on the lower half and then hangers on the top half ? Same thing goes for the space below the speaker soffit …as you can see from the pics the space available here is very small, again maximum I will manage to fit three very small ones in there… What do you think of having instead a superchunk with a channel for ventilation made with chicken wire the same way as above the speakers? Any thoughts much appreciated as usual! Many Thanks ciao Simo

I'm planning of using a 3mm plywood for the core, and 50mm insulation on the sides

John does NOT recommend plywood for the cores: he recommends a very low density, soft fiber board, called "Homosote", which is made from recycled paper: It's the type of board used for bulletin boards, that you can stick push-pins into easily. I don't think plywood is going to work correctly.

Following the distance recommended on John's design, i.e.150-200mm (I assume not from the center of the hangers but from its edge, well not a huge difference anyway),

As far as I know, John is talking about on-center measurements.

I measured that I would manage to place just three of them in there! It seems a bit of a waste of space to me, what do you think?

I may be wrong, but I reckon they will work OK. You also have to line the inside of that box (the walls, floor and ceiling) with thick insulation, so there will be a lot in there. And if it doesn't work well, then you can always take the hangers out and fill the whole thing with insulation, as a superchunk But John is probably the best guy to comment on this, as he has years of experience doing hangers, and seems to be the person who understands them better than anyone else. Maybe PM him with a link to this thread, and ask him to comment. - Stuart -

Thanks for your quick response Stuart, always informative and detailed. Strangely I can't find anywhere the Homosote in this part of the world, or any equivalent material light enough for that purpose - don't know why :horse: ?… so, due to this I was just following Glenn's advise (on this thread @ pag.6 3rd post from top) about using 3mm lightweight ply as an alternative (which it's very light indeed), and will be there just to have something to attach insulation onto :-) …but I'll keep searching for a low density fibre board - actually, anyone in UK knows where I can find it at all? Thanks for the "on-center" clarification Stu, and yes I will line the inside with insulation :thu: What you say about trying first with hangers and if doesn't work well convert it in superchunk makes sense ! Ciao

I've seen everything recommended as a core from cardboard to plasterboard, plywood being a very popular choice. Many studio designers have their own personal choice. Core material is not considered by many to be as relevant as is size and spacing as these hanger panels work on a very different principle i.e. waveguiding - which is not very well documented and perhaps not very well understood. The advantage of homosote, from what I understand, is that it will be more effective for lower frequencies. Homosote or soft-fiber board is the type of board used for making pin-walls, so if you go to the store and tell them you want the soft core of a pinup panel they should be able to source it. Failing that though, you could substitute cork (albeit rather expensive) or thick carton or cardboard - you might even try honeycomb panels, but plywood will also 'work' as Glenn suggested.

Thanks a lot for you very clear explanation Brian, much appreciated ! All the Best ciao simo

Sorry guys to bother you again with this, but… :oops: I've just found this website that sell notice board in UK made with 100% recycled newspaper, which should be what we want, right? BUT looking at the products specification I wasn't convinced by their density, which I think is a bit on the heavy side (500 Kg/m3)….I seem to remember that in another thread it was advised for the hangers' core to use something with a density of 160 Kg/m3 or around that. Basically my concern is that if I use this product as the core of my hangers it will make them too heavy, so they won't be able to move in sympathy with the sound as I believe they are supposed to? If you want to have a look at the website here's the link: - http://www.sundeala.co.uk/sundeala.htm - click on Notice boards - click on Sundeala Uncovered - click full product specification Shall I keep looking for something else lighter you reckon? :? Many Thanks in anticipation guys ciao simo

500 kg/m³ does sound a bit heavy, probably depends on the bonding agent. The panels I will be using are 10mm thick and weigh 2.3Kg/m² (so 230Kg/m³) see also http://www.johnlsayers.com/phpBB2/viewtopic.php?f=2&t=12365&start=45

The stuff I use is 400kg/m3 so that looks about right - I don't know where you got the 160kg idea from.

Brian and John - Thanks a lot for your response. John, the link that Brian posted (acoustic hangers) is where I got the 160 kg/m³ information…. BUT if you say that you use material that's 400 kg/m3 (obviously with success!) and what I found looks right, well that's good enough for me :D - Thanks ciao

Hello everyone…me again :-) sorry to post here so much recently …just a quiet time work-wise, so trying to get more stuff done with my studio. Four questions (apologies :oops: ) about the speaker box and soffit this time…. they might be silly questions, but ones that I'd like to get off my chest ! : Q1) Speakers height from floor: As it stands now the acoustic axis of my speakers is at circa 1.3m from the floor. I read everywhere that 1,2m is suggested, otherwise you need to think about tilting them down to face your head. To give you more information, my room height (not considering the false splayed ceiling or cloud that I'm planning to build) is 2.4m, so actually having the speaker's axis at 1.2m from the floor would land exactly at half way (50%), which I gather should be avoided as well… I could modify the soffit (not easily but I guess I could)…would you face the trouble? or if 1.2m is only a guideline, and so if my speakers are a bit higher it's nothing outrageous ? Q2) For the decoupling layer to line the inside the speaker box: I can find soft rubber strips of thickness ranging from 2mm up to 25mm, so I was planning on using a 5mm layer…Is that suitable in your opinion? Or would you go with a thicker / thinner one? Q3) For the external power switch for the soffit-mounted speakers: I'll try to explain this one with pics, hoping that it'll be easier to understand. Option 1: ... or Option 2: I'm planning on using Option 2 (as it would give a neater finish)…. would that be correct ? Q4) I've seen suggested somewhere around the forum to use a packing strap or a heavy string around the speakers in order to be able to pull them back out of their box if needed… BUT - don't laugh :lol: - my question is: how would you hide the ends of that strap for a neat finish? I mean, I read on another thread about leaving a few millimetres (if possible 1mm) gap between the front panel (bezel) and the speakers front face and to seal around the edges so they are decoupled…and then I end up with the ends of this strap / string hanging out of that gap? not very neat right? I can feel the solution it's under my nose but I have to admit I'm a bit puzzled …stupid question I know, but hey…i warned you at the beginning, didn't I ? :-) Thanks in advance for your help guys ! ciao simo

Q1. The 1.2m is just a guideline based on the average height of a seated persons ear. Measure from the floor to your own ear when seated normally to get the exact figure - it will probably be around 1.2 m. Granted that 50 % of the floor to ceiling is not ideal - hence the invention of the cloud so we can adjust this when necessary. Prepare your space for the inclusion of a cloud or drop ceiling over the listening position should it become necessary. Testing will quickly show if you'll need it, and then you can consider soft or hardbacked (modal problems) and whether sloped for reflection problems. Regardless, the correct height for the speakers is ear height. The space can be corrected. Q2. 5mm sounds good - important is that the weight of the speaker compresses the rubber, but not completely. If you lay out the rubber as you will eventually install it, then place the speaker on it and measure the thickness before and after, there should be about a 15 -30 % compression if I remember correctly. Q3. Not sure what the question is - it seems to be a matter of taste, but option 2 looks the most convenient to me. You might also consider controlling both monitors from a single switch. You've opted to install the monitors with their respective amps intact, hopefully the ventillation is adequate. Something else you might keep an eye on though - when I had my actives set up with a separate switch, they used to POP when switched on and off - the power switch on the monitors themselves had protection circuitry to prevent this, but my remote switch obviously bypassed this as they were always physically switched on. Perhaps you should test this before committing to a final decision. Q4. :) I've been pondering this same problem recently. If you come up with a good idea, let us know.

Q3: You're planning on adding ACTIVE monitors in a soffit wall. No problem, if you have proper heat exits build in the soffit. Active monitors have amplifiers. Thos amps will get warm, or even hot. The heat needs to escape or you'll blow your amps. You can either add a vent shaft behind the amps or detach the amp completely and place it somewhere else.

What can I say… Brian, your answers are as clear as ever, Thanks man, all of that totally satisfies my curiosity ! …and yeah, let's see who comes up first with the solution for Q4 :-) Ro, thanks for your response man ! Yes I'm planning on building the speaker box and soffit following John's design to allow air circulation: - opening above & below the rear of the speaker box - a slot on the front panel, above the speaker (connected with the top vent of the box via a 'tunnel' made with chicken wire or a duct - like the one used for the HVAC - to prevent the insulation to stop the air flow) - a port at the bottom of the soffit The idea of separating the amp makes a lot of sense (and I know Genelec supports that) …but it makes me nervous too :-) and I haven't taken that into account either when building the soffit… Many Thanks ciao simo

Just about to buy some rubber for lining the inside of the speaker box. Here's a chart I found…I thought it would be useful to post it here as a reference for everyone (hope you can see it ok !). Looking at the characteristics, to me it seems sensible to get the "Natural" one (first column from the left)….but you still have some time to stop me… :lol: Have a good weekend ! Ciao simo

Neoprene is what you want. Or even better, Sorbothane (which is not on your list). - Stuart -

Thanks Stuart for your response ! I managed to find a supplier for Sorbothane here in the UK… wow! that stuff IS expensive: 500x500 x 3mm (£39) 500x500 x 4mm (£46) 500x500 x 5mm (£53) 500x500 x 6mm (£60) I've seen Glenn suggesting on another thread as alternatives: Sylomer (I found in the same price range as the sorbothane), soft neoprene or closed cell foam… I don't know whether his list was in order of performance, but I'm starting (for my pocket) to fear so :( Would using closed cell foam be that bad, you reckon? :-) …as it's noticeably cheeper, you know ! :lol: Or if I stretch to the Sorbothane sheets, would the 3mm option suffice? I know you often like to quote on your posts that "every inch counts"…but at this stage of my build I would add that "every penny counts" :wink: ciao simo

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 -

Gotcha Stuart, thanks a lot for that ! …Right... :shot: 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: 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

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.

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

BriHar wrote:

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 :-)

BriHar wrote:

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.

BriHar wrote:

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.

BriHar wrote:

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.

simo wrote:

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?

simo wrote:

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?

simo wrote:

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

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.