What's the preferred treatment for ceilings 1st reflection points, above MLP and above speakers.

What's your preference and experiences?

 

I have been experimenting with 2D diffusion at ceilings 1st reflection points (Skyline type), i get more focus in the stereo image but i also loose height in the soundstage.

I'm about to try 1D diffusion instead to see results. 

Might be of interest, quite a lot of work in that thread all DIY.

Welcome to the Forum.

Photos and room dimensions help. If you are running REW and a calibrated mic, a waterfall graph is also helpful. 

 

Have been playing around with REW for some time, in the Impulse Response graph i think the noticeable peaks are ceiling and back wall.

Room sound is kinda dry i think (in a positive way) so no more absorption in the upper range, it's about 50/50 music/home theatre.

I have a pair of EQ Acoustics Spectrum 2 L10C Bass Traps in one back corner stacked, the other 2 corners i have Tuba HT horn subwoofers, last corner is the opening to hallway and i use a folding door to screen off to the hallway.

Ceiling is untreted, behind listening position i have 4 Slat AbFuser from Bluetone acoustics, got carpets on floor, heavy draped molton curtains in front of window (near side wall). I also use parametric eq to tame the lower frequencies.

 

 

 

 

 

 

Hi

I had a good long look at the response Waterfall graph with a really quite reasonable fundamental response.

Tried to emulate a graph of my own "space" with similar settings to yours. Didn't go all that well with the scale, but readable.

The lounge built has ceiling diffusers aiming at quelling a clap echo, that and a thick carpet with very heavy underlay. I practice a clap response initially  when evaluating spaces as it requires no tools and can yield a reasonably good evaluation just by listening to the burst decay, as in a pink, or sustained high frequency ringing sound.

Of note 

16 hours ago, Charson said:

Room sound is kinda dry i think (in a positive way) so no more absorption in the upper range, it's about 50/50 music/home theatre.

Talking ceiling absorption and looking at the 1200Hz and above decay times between both of the graphs, they are not far apart, 2.4m ceilings is hard to work with.

Absorption in this range tend to not dry out the reproduction but actually perceivably open up the space to seem larger.

However treatments through the 100 to 1200Hz does tend to "dry" this most interlegible, to a human, component of reproduction.

I've never been a big fan of diffusion as while it can have good effect in some applications, it does not tend to absorb decay, it mostly breaks up flat surfaces into smaller parts, good for first reflection points to subdue the combing effect but not great at absorbing the decay.

Of note the 2 graphs, seems t show a smoother high frequency decay time, without drying out the reproduction with the effect, simply put, more interlegible and defined very high frequency response.

The lounge has 4 differing layers of absorption plus diffusion.

1200Hz and up, 40mm layer of polymax and carpet of some +20m2

100Hz and up, via a 200mm air spaced polymax layering, +8m2 

30Hz and up, mass loaded, sealed air chambered vinyl membrane bass trapping at around 8m2 surface.

There is a diffuser array with 2 frequency ranges (1200 and 3500Hz) in addition although at about 0.7m2 on the front wall above the speaker set does not do a lot although it seems to garner a better quality stereo image effect.

There are plans to further treat bass with solid membranes, Vpr absorbers.

 

The lounge does not sound dry, if anything it sounds simply, better due to a balanced multi layer approach.

Personally looking at the 2 response graphs, your graph has a better fundamental response, but,  it still has decay lumpyness in the 1200 and up frequency range in comparison and might show improvement with ceiling absorb, rather than diffusion, in addition to the other trapping you have installed.

Sonically the lounge I'm in has a dry tonally correct, uncoloured bass response to the ear (preferable personally), but is balanced out with the layering into the upper frequency ranges. 

Try a good hard clap in your lounge and listen for the result, if it rings, there is room for improvement

 

playdough.

 

Edited January 22, 20242 yr by playdough

@playdough: Your scale is linear in your graphs, mine is logarithmic.

Will do some clap test later and see, last time I only had a few flutter echoes on the right side of the room.

 

Yes, low frequency decay is hard to tame, multiple subs in the right place will help if they are phase optimized and time optimized.

Can a VPR bass absorber be narrow width?

I ordered 1D diffusers to compare with my skyline diffusers (Vicoustic multifuser DC2). The plan is to put the Skyline above the MLP and at the front wall and use the 1D at the first reflection points in the ceiling. Will also test some absorption in the ceiling later.

 

Just found New Record Day's Youtube channel has some really good info:

 

 

Edited January 22, 20242 yr by Charson

Yes Ron does a good job and is extremely through. Kind of wished that had done similar during the last 6 months, although very happy with the result.

Still learning, happy to be coached   🙂 

8 hours ago, Charson said:

Your scale is linear in your graphs, mine is logarithmic.

Yea, wondered what went on there. Thanks for that, worked it out. Slice interval is out a little but the graph is better.

An old measurement of a basic test rig no EQ or TD, fundamental is all over the place. showing a fairly short reverb time through 1200Hz and above. Attributed to the thinner 40mm surface treatments. I like to have the noise floor present in the graphs.

9 hours ago, Charson said:

Can a VPR bass absorber be narrow width?

Interesting, from what I can read, they can be relatively thin, they have to be not square forming a rectangle, ideally 

There is an application here for at least 2, but they can be only 600mm x 2.4m. Should work, as it would have a fair area2.

The question I have is can aluminium plate at 1.2 mm be used instead of steel 🙂 

My guess is yes, although it has to be made and measured, first.

 

Yea, good luck with the QRD diffusers. Will be a good job and have effect at the positions you describe. 

I've been 3D Printing mine. 

I'll get through the EQ Wizard with the new speakers installed last week improve the fundamental now the stereo rig platform is in place with no more radical changes for a while. Has been a busy time.

 

Cheers.