Small room build in Essex - a couple of questions

[NickMac10]

I am in the process of building a room in my garage to be used as an 'office/ideas room' rather than a studio. I'm in a link detached house, so the garage connects to next door. Because of this, I don't think I'd ever be able to achieve enough isolation (within my tiny budget) to have the room as a functioning audio/mixing room, so it'll be acoustic guitars and some mics at most.

With that said, I'm still trying to reduce the sound transmission as much as possible, so I've made the walls and floor nice and heavy with 3x12.5mm plasterboard (walls) and 3x12.5mm plywood (floor), as well as a super(ish) door.

To cut a long story short, due to my poor construction skills, I hadn't marked the studs as accurately as I thought and missed one of the studs with three screws in a row on the last layer.
To what extent have I ruined all of the work I've put in with regards to transmission loss? And is this situation salvageable?! I'd hate to think three screws have ruined the whole project. My only thought was to try and fill the holes with acoustic caulk.


My other question was with regards to flooring. Someone told me on here a while back that any hard surface flooring is ok. I'm guessing this is for acoustic reasons? Is there any disadvantage to using carpet, in particular office floor tiles, which would be easier to move a chair around on that regular household carpet?

Thanks,
Nick.

[Paulus87]

Hi,

Did you build a room within a room or are all your walls/ceiling a single leaf?

Trying to understand why you think you've ruined your isolation... if you've built a two leaf system and missed the studs with some screws then surely those screws are not long enough to make contact with the second leaf? And if it's a one leaf system then those screws are not "shorting" out anything, since it's a single leaf system.

Either way, if you're concerned then yes you can just remove the screws and fill the holes with acoustic caulk. Caulk has roughly twice the surface density of drywall...

Regarding the floor, hard solid reflective is best with a treated ceiling. Carpet does not absorb much, only a tiny bit of the higher frequency range, but useless for broadband or bass trapping. The result is a dull sounding room, and since we generally try to maintain a fair amount of high frequency energy in the room we prefer hard reflective flooring.

However, since you are not really trying to make this a fully fledged studio you can do whatever you like, use carpet if that is what makes you comfortable.

Paul

[NickMac10]

Hi Paul,
Thanks for your reply.

It's a room within a room. Three layers of 12.5mm plasterboard on the inside of the studs, with a 20cm air space between those and the adjoining walls. The reason I was concerned is that those screws have gone through the plasterboard and into thin air, and because the whole idea is to try and keep the structure as airtight as possible, those holes have compromised that airtightness.
Acoustic caulk certainly seems like the way to go. One concern was that it would be really difficult to get the caulk all the way into the screw hole (without the use of a tiny syringe!) and that would still result in diminished isolation. But as you point out, the surface density is twice that of the plasterboard, so I'll plug up the holes as far as possible and that should do the trick.

Regarding the carpet, it wouldn't be for any absorptive properties. More for cost saving than anything else. My question was whether there would be disadvantage to using it, but as you mentioned it can make the room a bit dull.
You're right, this won't be a fully fledged studio, but I'll be doing more listening and mixing than anything else so I'd like the room to have a reasonable sound. I'll get hunting for some laminate/engineered flooring on eBay...

[Paulus87]

Man, you worry too much haha! that's a compliment.

Yes, really no big deal, you could either leave the screws in and caulk over it or just shove some thin backer rod in there, or some tooth picks...

If it was me I would just caulk it, as long as it's air tight on the surface it's not going to massively impact your isolation.

Yes, I managed to pick up some very good laminate on facebook market place for £100 which covered the entire control room floor (45sq.mt). It looks new.

Another cheap idea: if the existing floor is concrete then that is perfect already, if you don't like the look then you can paint it. If it's rough you can polish it or put a self levelling screed and paint that.

Paul

[NickMac10]

Haha! You're right, but thank you!

OK great, well I'll try and get some caulk in there and then seal over the top. Glad all is not lost!

Oh yes, I always forget about Facebook marketplace. I'll give that a try as well as eBay. The floor is concrete, but it's quite uneven, so maybe I'll have a look into the self levelling screed as an alternative. Good to know I have a few options!

Appreciate your advice.

Thanks,
Nick.

[DanDan]

Just a caveat. A hard floor is more hygienic and practical in some ways. However it is not more practical in other ways. Musicians tap their feet and move about on chairs etc.
This is why one rarely sees a picture of a musician in a studio without an area rug underneath.
The rug or carpet underneath will eliminate the HF aspect of very early floor reflections. This is either desirable or not sonically, but in terms of purity of the recording or indeed listening to a loudspeaker, eliminating those early reflections increases clarity by preventing HF comb filtering.
Clouds are always welcome and they prevent flutter echo between ceiling and hard floor.

[NickMac10]

Thanks DanDan, appreciate that info.

I have put a couple of clouds on the ceiling so that I could recess the lighting, so hopefully they'll help to limit the comb filtering. I do like the idea of the laminate with a rug under the chair, and I think it'll look nicer than the levelled concrete.

Many thanks,
Nick