Bass Trap / Acoustic Panel Experiences

[Agaton Sax]

methoslomenia

No nitpicking but for Googlers the word is Mesothelioma.Of all the things you do not want to die from this one is way close to the top.Imagine a  cancerous peel forming on the inside of your chest and squeezing and squeezing till that day when no air can enter at all. No cure and horrible,horrible to see. The further nice thing is that the disease typically occurs many years after exposure to  blue asbestos.Mean time from diagnosis to death 9 months without treatment or 8 months with treatment.

 Shed a silent tear for all the mineworkers,builders, hapless Transnet pensioners who spent their lives close to train brake pads and steam boilers or  just those people who grew up in the Northwest Cape or who lived close to a railway line where this crap was transported in open wagons.As for it being rare? Well maybe in countries that banned this ****,where it is not mined,where kids did not play on open heaps of this,where buildings with asbstos are covered in vacuum plastic and demolished. But not here China,not here.

No comment on the fireglass causing this bit.

[edward.ruthven]

I used a mirrow to determine the reflection points. I am aware the the side walls have two reflection points, one from the closest speaker and one from the further speaker. Considering my near field listening position the two points are very close to one another easily allowing one panel to do the job per side.

My lounge has a very funny layout with a small alcove on the right and a pillar in the centre of the room, as well as a jutting wall on the left. This has created a very difficult system setup.

[edward.ruthven]

See Photos of my layout without panels

https://picasaweb.google.com/109200963106610950753/Hifi?authuser=0&authkey=Gv1sRgCNu-lPnPtvD1Lw&feat=directlink

[joel]

Pretty much none of us are near field (the area where what we hear is predominantly from the speakers)
Due to the size of our rooms, most aren't far field either.

This means that most of us listen in a transitional area that consists of direct and indirect sound (I'm explicitly not saying early and late reflections as typical domestic rooms are too small for true late reflections)

To my mind (and anyone cleverer than me can correct me) determining your first reflection point by whatever means is only relevant if you assume that the wave that propagates from your speaker is truly omnidirectional, phase coherent and has a perfectly flat response.

In the vast majority of cases this isn't true.

If, for example I have an issue at a frequency where my tweeters start to beam, the first reflection point at this frequency would not be the same as a lower frequency. Were I to place absorption at the theoretical reflection point (to reduce the amplitude of the frequency that bugs me) I would make matters worse because frequencies other than the one i want to limit are being absorbed. That pesky frequency is now even more prominent in relation to the others.

While I'm a proponent of getting things acoustically better, the more I learn about the subject (and I admit that in relation to the real experts I know little), the more I realise that we need to look at every room as a separate entity before we can make over reaching statements and recommendations.

Sure treating early reflection points may help in many situations, but not necessarily all.

The other day I cam up with a simple and silly test. I hooked a mic up to my laptop, set my RTA to scope mode and played a pure sine wave.

When directly in front of a speaker, I saw, as expected a sine wave.
As soon as I moved as little as around a half a metre away, the sine wave started to become jagged (already showing room interaction) by the time I got to my chair it the shape was still sine waveish but it looked horrible. Sonically apart from level the sinewave didn't sound that different, despite there being a whole lot of harmonics.

Knowing the frequency I could if I wanted, have placed absorbers around my room until the sine wave started looking smooth again.
All this would have proven was that I had tamed one frequency.

Into geek area here so apologise for the long post and moving away from the OP.

[audiomuze]

No nitpicking but for Googlers the word is Mesothelioma.My bad, should learn to use spell check, albeit even the dictionary would've been lost on that one.

A friend's father suffered from mesothelioma.  An 80 y/o still capable of mowing the lawn on a half-acre stand, 3 months after sudden illness and subsequent diagnosis they buried him.

[Rodney_gold]

IMO you are already nearfield listening looking at those pics , the pillar behind you in the sweet spot could be problematic , but don't think so ,difficult to predict what the sound will be like in that room cos there lots of openings to other spaces.

[edward.ruthven]

I have put a mid/high panel on the pillar now plus the ones at the first reflection points. after some listening last night I find i am now hearing small details that were not there beforehand.

I am now going to purchase the rigid fiber boards for my bass traps. Thinking of 1 50mm u-therm 8 (120kg/m3) and 1 50mm u-therm 6 (66kg/m3) per panel. I will be buiding 4 of these so that i can have floor to ceiling panels for the front wall. will move the think pink bales to the back wall.