John Sayers' Recording Studio Design Forum

guys you´re so cool...

thanks alot... keep motivating me!

but sorry for my dumbness: whats the acoustic axis of the speaker? not just the middle of it? maybe i translated it wrong and just dont get it...



edit: ok i just checked again and just corrected the speaker position more to the middle but thats the most i can go i think (because the wood baffle need to be at least 3 times the half diameter of the woofer right?) if yes that would be 45 cm left and right minimum in this design...

with this speaker postition my ears (not the apex of the triangle) are at ~41%

i think this is good enough for me

The acoustic axis is kind of like the center point of the expanding sphere of sound emitted by the speaker. Some manufacturers indicate where it is in their specs (check your user's manual), but most don't. It is somewhere in between the woofer and tweeter, normally much closer to the tweeter than the woofer. Imagine that you are drawing a line on the front panel of the speaker itself, joining the center of the woofer to the center of the tweeter: the acoustic axis of the speaker will most likely fall somewhere along that line, and will poke out from the speaker panel at right angles. If your speaker specs don't show where it is, then you can consider it to be the center of the tweeter and you won't be far wrong. (Some people even say to always use the center of the tweeter, and while that is close, strictly speaking it wont be exact. But we are talking a few centimeters, at most, so it's good for a rough estimate).

Regarding what you did with your diagram: I was thinking more of moving the entire soffits! I mean, cut a slice off each side of the center panel in between the two soffits, and bring each of the soffits closer to the center. That way each speaker will still be centered in its soffit. You can even adjust the side walls a bit, if you want.


- Stuart -

_________________
I want this studio to amaze people. "That'll do" doesn't amaze people.

ah ok i´ll do that... what about the front panel between the soffits? can it be fully absorptive or does it have to be reflective? because i really like this angle in the design...

It can be either, but if you want to make it reflective then you'll have to figure that angle very carefully to avoid reflections bouncing off it and back to your ears.

- Stuart -

_________________
I want this studio to amaze people. "That'll do" doesn't amaze people.

does reflective have any advantages over absorbtive in this kind of soffit front?


edit: by the way: i love this forum

In my personal opinion, no. I'd go with absorption: I just don't like the idea of having reflective things in front of me, and also in front of the speakers. It's really hard to figure out where those reflections are going: maybe coming back off the console or desk, or the floor, or side walls... Unless you have a ray-tracing program, it's hard to figure more than two bounces. Even one bounce is hard enough!

(But I'm sure others might have differing views... )


- Stuart -

_________________
I want this studio to amaze people. "That'll do" doesn't amaze people.

Hi Guys, for those of you who are still interested:

dont think i´m not thankful or that i just suck up infos from this forum and then leave...

i was just so busy with building and earning money that i just didn´t manage it to post regularly...
AND i got a girlfriend and a dog

i made a huge process in building the studio and i think you guys need to know whats going on...


please dont blame me for my non-existing building skills and please dont blame me for having done mistakes (i´m sure)

but how it is going to be when its finished is enough for my (home) needs

plus i am very sure i broke some rules, especially when it comes to soffit mounting

but i did a couple of measurements recently and it turned out better than expected...


but see for yourself...


enjoy

basic framing

framing filled with rockwool for absorbtion... i had itchy pain all over my body and IN my body even days later

starting rear wall framing and rockwool stuffing with cavity for my diffractal diffusors

whole backwall trap is 50cm deep... unfortunately i couldnt fill the corners more, because of the doors on each side...

i think i had to stuff 12 packs of rockwool in this frame


i also doubled checked with the diffusors if im still on the right course

adding melamine foam (basotect) to the side walls for raising the efficiency of the absorber and as a first trickle protection (i had a couple of mats lying around)

first positioning of speakers and measurements of the room so far

i decided to add hangers to the whole concept because i had bass problems and i wanted to get rid of it... i also had spare room beside the speaker front because i changed my original layout a bit for not sitting in the middle of the room... i´m now at 38-39% of the room front... speakers went more together so why not adding hangers...

as much as the wallet allows


i tried to differ the hangers in size and thickness for making them more broadband... i really didn´t know what im doing exactly because there is no science about them anywhere.... but in the end they turned out to work just perfect... i didnt take screenshots of the measurements but i can tell you i had almost 1,5 seconds decay at 50hz before and afterwards (with all hangers and backwall absorber) i had only 450 msec... i think its a great improvement


by the way... all frames on the ceiling and floor are glued, no screws at all, because drilling in stell-reinforced concrete would have driven me crazy... this was easy, cheap and fast...

and its so extremely stable, its crazy...

starting the speaker front

here comes the crazy part


i put my speakers on the thick mdf plate for a vibration test just to look how the framing behaves and it was horrible... everything was shaking.... even the wall vibrated and sound transmitted to everywhere... floor, rooms above, etc...






i know its a early building phase but to avoid fights with my neighbours i just decided to decouple everything a bit more

i did cut the mdf-board to build a tower of concrete blocks underneath the speaker-box... 400 kg of pure concrete per side placed on thick rubber

that was the fastest, cheapest and easiest way to decouple the speakerbox from the room

i paid 80 euros for all of the concrete plus 20 euros for the rubber mats

results were very good, nothing was vibrating, i think it was enough mass to reduce the mechanical vibrations

here a little pic where i started to place the concrete (forgot to post this one before)






after that i built the thick mdf-box around the speakers filled with rubber mats for a very tight fit of the speaker











i then placed the mdf-box (very heavy) on top of the concrete with big sorbothane blocks underneath for even more decoupling