Hy there, i am in the construction of small studio (music, dubbing,post). the aim here is to build a serious recording space with a very low budget and a lot of diy!!!
i am at the moment finishing up the soundproofing of the control room, and need to start the acoustic treatment (i will starting a construction thread soon :lol: ). i went for LEDE room with RFZ but need to know how to treat my back wall to get decent ISD gap with the reflected sound (back wall). i have flush mounted speaker (nearfield) in front wall within solid wood, porous absorber 20cm deep filled with 80kg/m3 rockwool of 8cm (2x4cm), and various traping on top of those panel (yet to be design) which i would like to tune to pb frequencies (at the mo 40hz), i will then design a cloud on top of the sweet spot and may angle the top window wall. as everything is conected together in terms of planning, i want to know how i could calculate the delay of the returning (reflexion) sound wave from the back wall. i already use REW but not sure how to get a reading of that. also this control room is conected to a larger live room around 2/5 bigger than the live room (that i planned to treat with modular acoustic).
control room dimension are 4.6L x 2.85w x 2.2h
i have been sent to some very interesting reading in other forums, but there is always some dark area on actually applying different acoustic concept. (well for me anyway)...
thanks in advance for any light on the subject
Hi there first post-isd gap help
Originally posted at johnlsayers.com, topic 18042.
Hi "kaneyking". Please read the forum rules for posting (click here). You seem to be missing a couple of things! :)
Anyway, a couple of comments/questions on your post:
How did you do that? (Materials, technique). That might have an influence on the treatment, so it is important to know. Photos and diagrams would be helpful.i am at the moment finishing up the soundproofing of the control room,
LEDE and RFZ are two different things. Yes, RFZ is an extension of LEDE in some ways, but there are many differences. It would help to know what you did to accomplish your RFZ layout, in terms of angles, positions, and geometry. LEDE is an old concept, dating back about 30 years, and seldom used these days, since a pure LEDE environment is too dead, and unpleasant to work in for long periods. RFZ deals with that, to a certain extent.i went for LEDE room with RFZ
There is nothing at all you can do to a wall to increase the delay, except move the wall! The delay time is determined entirely by the physical distance that the sound waves travel, which depends ONLY on the dimensions of the room. Since your room is 4.6m long, and sound travels at roughly 343 M/S in air, it takes about 13ms for sound to travel from the front wall to the back wall, or 26 ms for the round trip. However, your speakers are obviously not located at the front wall, and neither is your head, so the actual delay will be somewhat shorter than that. Assuming a typical layout, the actual delay is probably around 20ms, which is fine. Which is a good thing, since treatment cannot slow down sound waves! If you needed to increase your delay, the only option is to move the walls. So you probably don't need to move that wall to increase the time, fortunately. However, you DO need to treat it, in order to get the level down to comply with the RFZ design parameters.but need to know how to treat my back wall to get decent ISD gap with the reflected sound
You say "speaker" not "speakers"? So you only have one speaker?i have flush mounted speaker (nearfield) in front wall
I don't understand. If it is flush mounted properly in an infinite baffle, then where did you put the absorption? The infinite baffle must be very massive, very rigid, hard, and solid. You cannot use rockwool for that! :shock: The best material is concrete or brick, but must people use two or three layers of thick plywood, OSB, MDF or something like that. Maybe you should post some photos here of what you have.in front wall within solid wood, porous absorber 20cm deep filled with 80kg/m3 rockwool of 8cm (2x4cm),
You cannot put anything on top of the infinite baffle (front surface of the soffit). It must remain flat.and various traping on top of those panel (yet to be design)
I'm not sure what you mean by that. Please explain that more clearly. Based on your dimensions, your room does not have any modes at 40 Hz. Your lowest mode is the 1,0,0 mode, at 37 Hz.which i would like to tune to pb frequencies (at the mo 40hz)
Measure the distance in meters, divide by 343, then multiply by 1000 to get the time delay in milliseconds.i want to know how i could calculate the delay of the returning (reflexion) sound wave from the back wall.
It should show up on the impulse response graph, as a peak at around 20 ms.i already use REW but not sure how to get a reading of that.
That's not a very good ratio. It fails 2 of the 3 critical tests used by the BBC and others to decide if a room is good for critical listening or as a control room. Why did you choose that ratio? Also, if you have an RFZ design, then the room is not rectangular anyway, so please provide a diagram showing the locations, dimensions, and angles of all six walls. - Stuart -control room dimension are 4.6L x 2.85w x 2.2h