Actually neither ear nor driver height unless the two are the same, rather it is the height of the relevant point in the path from midrange and tweeters to your ears. If there is enough difference between driver and ear heights to make a difference you can calculate assuming the sound to be travelling in a straight line with the angle of reflection the same as the angle of incidence - but it is often easier is get someone to hold a mirror flat on the wall when you are in the listening position, and get them to move it (keeping flat against the wall) until you can see the reflected image midrange/treble drivers. The point of reflection gives the position the panel should cover, and also shows you the correct horizontal position as well as vertical. The same with the ceiling, though not quite as easy to hold a mirror against it. In practice a panel should be -and is likely to be - large enough to cover variations in precise listening position: which again is easily checked with the mirror while moving between the range of possible listening positions, and ensuring the panel covers the range of reflection points.
It depends so much on the speakers, room and layout, but I am By no means sure it will be that high a proportion. Where there is bass boom that will decrease, with much more controlled bass as a result (and removal of ‘one note bass’), so for people who feel bass is too much in their room they may perceive less bass - and that in turn may open the door to full range speakers that they may previously have rejected. An increase in bass surely would only happen where cancellations are of significance.
Otherwise I agree with your post. I have measured my present room, and where I had a major problem with cancellation before adjusting positioning, the main issue now is bass decay time.
N.B. I now sit relatively near field, and pretty much on the 38% positioning point, symmetrically in a wide, heavily carpeted, room so the most significant near reflection point is ceiling. I was going to treat the room but with a planned house move on the horizon it seemed better to wait. My dream is to remove the walls - but I am aware that reality will be far short of that. I am just hoping I can manage to get a better proportioned room to start with.
Absolutely, that what’s I meant. And the mirror trick is of course the best way to find those reflexion points, both speakers reflexion points:
Good point, I had forgotten the opposite side speaker! However, the shorter the path the more significant, and floor/ceiling are often forgotten, yet are often the shortest paths/earliest reflections.
Hi Thomas, your room looks great and imagine it sounds superb. Can I ask about speaker placement. I notice they are asymmetrically positioned to the left of the room. You have some absorbtion and diffusion to the left. Did you treat the right hand side of the room and if so did you need to compensate for the asymmetry?
It sounds great now, but was really unpleasant before.
It took me ages to fine tune it.
Interestingly the dissymmetry wasn’t that difficult to solve.
Here is the treatment applied:
Sum up:
- 19 x Bass Traps
- 22 x Foam panels
- 12 x Diffuser panels
- Streamer Pro high efficiency acoustic veils all around the listening area
Details:
K
4 x : Vicoustic Super Bass Extrem (back corner)
H
9 x : Vicoustic Multifuser Wood 64 White
C
3 x : Vicoustic Multifuser DC2 white (cute/adjusted)
E
16 x : Vicoustic Cinema Round Premium
A
2 x : GIK Monster Bass Traps - Thickness 28cm
B
2 x : GIK Monster Bass Traps -Thickness 20cm
D
4 x : GIK Monster Bass Traps with Membrane Tech
Thickness 17cm + 2,5 cm air gap.
F+G
4 x : Vicoustic Cinema Round Premium
+
Streamer Pro – Acoustic veil
L
6 x : GIK Monster Bass Traps - Thickness 17cm
+
Streamer Pro – Acoustic veil
Not on the picture
1 x : GIK Monster Bass Trap ( 180cm x 55cm) - Thickness 17cm
+
Streamer Pro – Acoustic veil (cuts the room in two)
Thanks Thomas. I performed a rough experiment this evening. Purchased 6 slabs of 10cm thick rockwool. Wrapped them in weed suppression material to keep the fibres in check. Laced in two corners on front wall, one to my left on back wall and one on window cill behind my head. What a difference, everything is improved even with a crude experiment!!! Once sofas have been delivered in a couple of weeks I will experiment again. I can only imagine what correctly made traps would bring.
The corners are doubled up so 20cm thick.
Well done StuW!
If you’re planning to build the panels yourself, then make them as thick as possible. The ticker the lower the frequency you’ll be able to absorb, and that’s your very goal.
You’ll end up absorbing evenly throughout a large frequency range, and therefore obtain an even decay time (which is key!)
Make your corner absorbers floor to ceiling, as thick as possible. You’ll easily find some nice DIY instructions on youtube.
You’ll have the feeling of having “less bass”, which can be disturbing/unusual.
But that’s just a feeling. What you get is less noise! Double-bass lines will be much clearer and easy to follow. At the same time, mids and highs, previously covered by the noisy low end, will be more precise, clearer and therefore provide a nicer stereo image.
There is no such thing as correctly made bass traps The only thing that actually counts is the amount of porous material (rockwool or glass fiber).
Making them nicer won’t help. But nicer is cool
Well, that’s not totally correct. Having your rockwool in a nice wooden frame allows to add some air between the porous material and the wall, which will increase the bass trap efficiency.
Have fun!
Her is an idea for your bass traps’ frames : IKEA shelves!
Fill them with rockwool or fiber glass, remove the back, then staple the whole thing with a nice fabric (buy if from it from GIK, but don’t buy the cheapest…)
Simple and easier then building the frames yourself.
Just an idea
Whilst the thicker the better, the density of the fibreglass/mineral wool panel also has an influence. Received wisdom is that around 40-50kg/m3 is probably the best compromise of characteristics.
Right, probably closer to 50Kg/m3.
Owens Corning 703 fiberglass panels, which is usually the recommended, is 48Kg/m3.
Of course, Owens Corning’s fiberglass insulation is expensive. One can achieve the same results with other brands and materials (rockwool)
I guess when I say correctly made I mean with rigid rockwoll/fibreglass. Mine aren’t particularly dense just the standard DIY loft insulation. Maybe some flex range technology would help?
I don’t think I will get away with floor to ceiling but some 1200 high tri traps or soffit traps in the front corners would get passed I think. We have a friend who is a local artist so I am looking to get two 244 impression panels either for the front wall above the TV or side walls. Interestingly I placed a panel in front of the TV between the speakers and this seemed to spoil the imaging, too much absorbtion maybe?
If you’re planning to order your panels (not building them), Monster Bass traps are preferable (thicker).
GIK Acoustics can make them to your needs: dimensions, depth, fabric and even the printing thing. Just call/mail them.
None of my Monster Bass Traps are standard, GIK did a really good job!
If the TV and rockwool is “aligned” with or slightly in front of the speakers, close to the drivers, you’ll absorb mids and highs (Take some pictures).
Mids and highs are responsible for the stereo imaging.
Furthermore, placing absorption between the speakers and not in the corners might create some kind of imbalance.
Well, this is of course speculations only.
Cheap as chips and worked a treat
150mm rockwool with 50mm airgap
When I get round to it will get better cloth covers
The wooden frames are old scaffold boards planed etc
My experience of DIY loft insulation is the stuff that comes in rolls, which is low density unless compressed, by design fluffing up to its specified 100mm, 200mm or whatever when unrolled, and not very sound absorbent compared to mineral wool ‘batts’ that come as flat sheets of the specified thickness, almost panel-like but floppy: As supplied by general builders’ merchants more often used for wall insulation or sound insulation between floors as well as specified acoustic uses. They are sold by thickness and density, ranging typically from 10kg/m3 to over 100kg/m3, and products in the middle of that range, such as 40, 45, 48 or 50 kg/m3 depending on brand typically being reported as most effective for this particular function.
Hi IB it was the acoustic rockwool bats 100mm that I used rather than the roll. I am not sure if this differs from rigid rockwool or fibre glass for bass absorbtion?
What you used is probably the right thing or pretty close - when you said DIY loft insulation I was picturing the fluffy rolls for thermal insulation!
Rockwool RWA45 is good imho
I believe this is what I used.