Comparison very good room acoustics with Nap135 against bad room acoustics with Nap500
Since 1986 I rented two dwellings being situated next to each other. Before the normal bricked partition an additionally swinging wall was attached because of a better noise control.
My dealer advised me to remove this wall in order to receive better acoustics.
Since the room should be used exclusive as music room, I could set up long cabinet diagonally to the available 250 m, so that a corner 10 cm and the other 50 cm before wall was. Behind that 1.5 m high cabinet I filled up swallowing materials with sound.
At the wall before that the SBLs was was otherwise nothing different one. At the opposite wall was mentioned cabinet. Here I hung additionally still another thick carpet up. All records (ca.1000) are accommodated in open shelves.
The room is 6.7 m x 4.05 m and 2.5 m highly. The acoustics in the room were until recently excellent. I operate my SBLs with 2*135 for tweeter and the 500 for bass/middle. (first in reverse with clearly worse result.)
Because of a pending change of residence I had to let the swinging wall attach again in my music room. Otherwise in the gear nothing was modified. The result was greyful. Now overemphasis of the in the middle, sharper heights. Beforehand also finest sound events could be assumed at the same time with the loud tones - it was thus very close at life.
Before the installation of the swinging wall the 500 was short for one week with the dealer, so that I had to hear passively with 2*135. 2*135 beforehand sounded better than now Scap Snaxo, 500,2*135.
I in former times already knew that good room acoustics is important - I had nevertheless not expected this result.
The room acoustics is obviously still more importantly than the gear itself. While it is very simple however, for more cash a better system to buy it is very difficult to find someone which can improve the room acoustics.
Ulrich
Posted on: 03 October 2001 by Allan Probin
Ulrich,
So you are now having to listen to your 500 system in a poor environment knowing that the 135 system sounded better when used in the larger room. I can sympathise with you having been through a similar ordeal myself.
Small rooms with parallel reflective surfaces are extremely hostile. I've found two aspects to be fundamental to retrieving the situation.
1) Speaker placement. Bringing my SBLs closer together went a very long way towards getting rid of an overly strong bass. Along my 14ft wall I ended up with the SBLs about 5ft apart (centre-to-centre) so that the wall was divided roughly into thirds. This also had the overall effect of making the system sound not only lighter but much faster.
2) Reflections. In a small room you are always going to be close to strong reflections. This is what tends to limit the ability of the system to be played loud. Try moving your head slowly backwards and forwards, this will probably reveal listening areas that are alternately very harsh and very soft, even within a distance of a foot or so. This probably comes about because of interference patterns created from direct and reflected sounds. Trying to absorb reflections using things like rugs on the wall is definitely the wrong way to go - they tend to kill the music. I'm using fairly large home-built diffusors on the wall and ceiling that look reasonably discrete when painted. Using diffusors to lessen reflections seems to retain the tune much better than using absorption.
In a situation like this it is a dilema that 135s are quite soft at the frequency extremes compared to a 500. In a harsh environment, this can work to the 135's advantage. The 500 is capable of putting out a huge amount of bass energy into the room and this can be revealing of problems that may not have been apparent before. In addition to this, the 500 sounds so much cleaner than 135s that reflection/harshness problems can become more apparent and take on more significance.
Most small room problems can be overcome, it just takes a bit of thought and effort. Although extremely frustrating at times, superb results can still be achieved.
Allan.
Posted on: 04 October 2001 by David Hobbs-Mallyon
Allan,
Could you desrcibe in a bit more detail about your diffusors and what you do with them?
My experience with attempting to absorb using rugs on the walls is I end up with a clinical sound, which I think sounds worse, so would be interested in your experience with diffusors.
David
Posted on: 04 October 2001 by Dev B
I had the similar problems in my small listening room when I lived in Aberdeen the room was 15'x11' with parallel reflective surfaces. I had the SBLs along the long wall. To be honest, SBL's were just too big (in sound terms for this room), I never had a problem with boomy bass partly becasue I never sat back far enough to experience much bass. IBLs/Kans would have worked far better in this installation. My feeling is that I used to drive the system harder than now to get a sense of bass weight, etc.
My current room in London is much bigger, I sit approx 13ft away and have no back wall so to speak as the room is an 'open space', and although the room is a touch 'lively' I don't need such 'power' to achieve the same 'scale' and 'volume'.
Interesting discussion.
Dev
Posted on: 04 October 2001 by Allan Probin
David,
The principle behind a diffusor is that sound is scattered randomly when hitting the surface. An ideal diffusor would scatter energy in a hemispherical pattern. Because the energy is 'spread-out' like this, the amount that actually heads in your direction is quite small.
The problem with using absorption is that it tends to be extremely difficult to absorb evenly throughout the frequency range. They tend to suck-out the high frequencies and have very little effect at low frequencies - and very uneven inbetween. This results in a tonal imbalance whereas diffusors tend to behave much better and retain a balanced level of high frequency energy in the room whilst still managing to attenuate strong reflections.
My ceiling diffusor is approx 4ft x 4ft and placed roughly in the middle of the ceiling where reflections from the ceiling would normally travel to the listening position. Its made from smooth-planed 18mm x 75mm section wooden slats placed parallel to the speaker wall and randomly spaced. Painted white (to match the ceiling) it blends in quite well.
My wall diffusor design is a bit more complex (and more efficient). Its approx 4ft wide by 2ft high, again built from 18mm x 75mm section, but arranged into cells of random width and random depth. If you take a look on the RPG acoustics site www.rpginc.com I've build a kind of hybrid between the Formedfusor and Omnifusor. The wall diffusor is built large enough so that it covers the reflection points of the left and right speaker on the same wall.
Additionally, on the back wall I've deliberately chosen to use CD racks that pigoen-hole the CDs into compartments approx 6"x6". These pigeon-holes are randomly full. This is a really discrete way of using diffusion. [I'm using 5 Ikea Benno CD Towers in birch at £35 each]
I still have a small amount of absorption in two of the corners and some on the back wall just to mop-up some stray bass. But the more diffusion I put into the room the less absorption I seem to need.
Dev,
My room is 14ft x 11ft. When I first tried Kans in there I was shocked at how good they were. Now I've addressed a few room problems there is really no doubt about how much better the SBLs are despite the room constraints. Maybe if you find yourself up-north on the A1 you should call in for a listen.
Allan
Posted on: 05 October 2001 by bob atherton
Ulrich,
I had a very big problem with room acoustics when I moved to our home with a 4m x 4m listening room. I found that source ,amplifiers & set-up still made important differences, but that speakers were crucial & very fussy.
It could be that SBL's in your new room are just not the ideal speaker. I'm confident that the 500 with the 'correct' speakers will outperform your SBL's. Don't give up on the SBL's yet though. As Allan was explaining positioning of these is very important.
My room just will not take a medium size speaker so I went from Kans to IBL's, though I think I'm going to go back to Kans again.
Good luck & keep us informed.
Bob.
Posted on: 05 October 2001 by Allan Probin
quote:
I went from Kans to IBL's, though I think I'm going to go back to Kans again.
Bob, having used both now, IMHO - the Kans have it. Kans are certainly more fun, the IBLs sound a bit 'tight' and don't let go quite so easily.
Allan
Posted on: 05 October 2001 by bob atherton
Allan,
Good to hear from you. I am beginning to think that as good as IBL's are,& they are very good, they maybe lack the degree of 'fun' that is in the Kans. Also I want to work towards a CDX & XPS or CDSII, & this would free up some funds for that.
I will keep you posted anyway.
Do SBL's 'let go' more that IBL's?
Bob.
Posted on: 05 October 2001 by Ulrich Hohn
Allan and Bob
thank you for your pieces of advice. In the meantime I am taken off from the flat let for rent and live in my own house. Here again quite different problems expected me: mine musicroom has a suspended ceiling, those strongly vibrated.
Remedy: More than 50 holes (diameter=8cm) were bored into the cover. Then the gap between concrete cover and the suspended cover was filled with Isofloc. This is an insulating material, which is won of old paper. After these dirty work the carpet had to be renewed. The acoustics in the bass became quite good. The heights are not yet quite optimal, since large windows are opposite the loudspeakers. The room is 5,70 m x 5,20 m largely and 2,55 m highly. My dealer finds the acoustics altogether good. I am also quite content.
Ulrich
Posted on: 05 October 2001 by Allan Probin
quote:
Do SBL's 'let go' more that IBL's
Yes, but perhaps not as much as Kans. Kans and SBLs are about on a par though with that emotional communication thing but Kans do sound a bit monochromatic, in contrast to the SBLs which sound rich and vibrant. The clincher for me is that I forget all about speakers when the SBLs are in. Oh yes, and then there's dynamics, weight, scale ...
Allan
