Kanef

Thanks Terryo I to have had experience with these beautiful pieces of interior design. Like so much Italian design, form does not follow function. Great for corporate. Board rooms etc. Not well suited as acoustic room treatments as pre and post treatment testing we’ve found. If you have some test results you wouldn’t mind sharing I would be interested. cheers Kanef

Always leave electronics on. An air conditioned room set to 25C will ensure best listening.

If you have a well designed room you’ll find yourself immersed in 110db Peak sound pressures especially on well recorded hi dynamic range material. Atmos?

Most straightforward way of putting the clipping concern to bed. check the rail voltage on the power amp feed. if you have 100 VDc across the two legs you’re not going to go into clipping any time soon on 95dB /w sensitivity bass drivers. The driver will be good for 105 + dB sound pressures in a normal listening room. Put them in a paddock and you could scare the cows.

No mate amps do not require Burn In. You’re experiencing designed in non linearity. A well designed reference amp will not interfere with your listening experience. From day one. Actually it’s likely to be the pre amp section that’s giving you grief.

Hey Dave your ears are telling you that the room absorption and time signatures are all out. You’re now experiencing the unfortunate fact the absorption is not reverberation. Reverb time used to be used as a proxy for attenuation. However the science has got a lot better since the 1950s. Any room treatment MUST start with bass treatment. As can be seen in the SPL graphs large low frequency energy waves are sloshing around your listening room completely unattenuated. These high energy waves are also producing the harmonics that you see on your SPL graphs, reaching well into the voice range. happy to help out if you wish.

Yes drapes and furnishings need to be factored in to any room analysis, either by Sabin absorption summing or better, actual room acoustical measurements. However soft furnishings offer only minor absorption. Any room, especially a small room, requires substantial and well designed passive absorption in order to produce a response that is acceptable. Remember that the objective is for the room to effectively disappear from the listening experience, allowing only the direct sound from the loudspeaker system to prevail. Otherwise why would you spend many thousands of dollars on your system. Room resonances, especially low frequency resonances, distort the sound coming from your loudspeakers. Why would you want that? Successful room treatment must start with treatment of the lowest frequency modes in the room. If you try for the mid range first then you’ll never make it because you can’t beat out the high energy bass modes with mid range treatments. The physics doesn’t allow it. And if you install diffusion before dealing with everything else your just going to amplify all those lower distortion modes and you’ll end up in a worse situation than when you started out. A note on XHD. The bass absorption profile of XHD 50 mounted is shown below. The absorption response is substantially flat across the bass band, however the absorption rate low. This example illustrates one of the problems with the ISO 354 standard that NRC is derived from in lab testing. The standard uses the T20 reverberation time, that is the time taken for sound level to drop by 20dB. So a LARGE sample is placed in a room with known decay times and the resulting NRC values are calculated. The main issue with this approach is that T20 decay is not the important sound absorption characteristic that is required in a room. In fact excessive T20 decay is a real issue in a room and can make the room sound ‘dead’. Everyone will have heard this in rooms that use glass wool as an absorber. Which was a popular low cost approach in the 1960’s and is unfortunately still being used today. Contrast the XHD profile with the absorption profile of our Axial Mode absorption panels which have been designed to deal with the kind of primary mode issues that are so annoying when listening in a small room. I hope this helps you. cheers Kane

Re cutting XHD. Hot wire works well.

We manufacture the Super 80. However I would need to do some measurements on your listening room. No charge. Then we need to discuss the results and make a plan. This will ensure we identify our target. Then we’ll know when we get there.

I always rely on my ears also. It’s what is between them that’s unreliable. The road to psycho acoustic nirvana is littered with the bones of those who listen but don’t hear. We all hear what we WANT to hear. Especially when we’ve invested hard earned money. I’m happy to help when ur ready. Everyone comes around. Eventually. cheers

The strong bass boom introduced by your room size can be seen in the modal diagram below. The fundamental is at 43Hz. Then successive harmonics beyond. Until the fundamental is dealt with, that energy will create unwanted harmonics that smear the sound stage. Your listening room has 12 to 15 dB of boost at 43 Hz. The very small amount of absorption provided by the units you’re contemplating will do nothing to improve the situation. (As an aside the corners are not the correct placement for bass absorbers. They may be aesthetically pleasing but acoustically they’re almost useless in this position.) The only method of addressing sub and mid bass successfully is with mass coupled with absorption. The NRC coefficient stated @ 50Hz is 0.2. But what is this a measure of? And what happens below 50Hz? Our Super 80 bass absorbers have an NRC of 0.6 right down to 20 Hz. Nevertheless, in a 48m3 room it will require substantial amounts of absorption, especially if you listen at high volume. (Orchestral Music recorded properly can have a 100 dB dynamic range). Correct room treatment requires careful measurement and then proper design. When this is achieved the resulting listening experience, even in a small room, can be remarkable.

Reason for asking is that QD is usually the final step in the room treatment process. I’m interested to learn what you’ve done and how.

Cubes are notorious. Would you mind recording some measurements with your iPhone? I’m like to learn more. Cheers Kane

Small rooms create large challenges? Below is the result from a quick Room Sim run using the room dimensions you provided. Note that I’ve placed to speakers and viewers 0.8m from the walls to reduce baffle effects. Room correction gets more demanding as you get closer to the wall surface. Room modal response with no treatment is shown below. I’ve turned off tangential and oblique modes as these complicate the discussion and can be dealt with once the primary modes are tamed. (green lines are axial width modes, red lines are axial length modes and blue axial height modes) Room treatment starts with the lowest frequency mode and works up. These modes contain large amounts of energy and in a small room play havoc with sound perception. Im sure that you’ll try to PEQ these modes out first, as I did when encountering small rooms. However I concluded that the ‘cure’ was worse than the disease. The SPL graph looked better but unfortunately the sound was worse, even with high end DSPs. Which is why I’ve developed passive absorption technology that is capable of treating the high energy problems. PEQ can then be used to polish the room response. Once we have the high energy problems ironed out then we can deploy diffuser technology, smoothing the midrange and beneficially make the room feel acoustically larger than it is. The finishing touches can be acoustic drapes and quality acoustic absorption foam. Remember that we’re dealing with room response. We want the room to effectively disappear, allowing you to listen expensive loudspeaker system directly. First to the 21.4 Hz width mode. Dirac can deal with this one using a sharp bass roll off starting around 30 Hz. Our Super Bass carbon absorption technology will absorb what Dirac can’t roll off. Our Super Bass response is shown below. The Super Bass technology is a combination of diaphragmatic panel and low frequency absorbing carbon. These units are 550mm * 550mm * 300mm deep. Or we can custom build to your requirements. Alternatively we can deploy our Super 80 carbon technology. The room characteristics show a serious modal grouping between 40 and 63Hz. This is a common mode in small rooms. I recommend using notched absorption. I designed the Notch 60 absorber for this purpose. These units are 550mm * 550mm * 90mm deep. Designed for wall mount, for mobile panels on castors or as build ins for standard stud walls. To get the best results possible the four walls will need extensive absorption. Treatment can be phased as budget allows. Where possible walls should be acoustically treated. Below is a scenario with your room treated with 20 Hz to 100Hz absorption. 33% absorption front and rear walls, 50% absorption LH wall and 66% absorption RH wall. Further measurements and work required to get the result however I hope that this gives you some ideas. Kind regards Kane

Hi Marc You have a lot of advice so I won’t add. So when you reach the point that you’ve had enough of muddy bass and messy soundscape then I’ll be happy to chat. cheers Kane

Martini XHD will help absorption of your room axial mode reflections. However the material is not particularly linear in its response as can be seen in the test results below. Referring to first image, the blue line is the XHD at 50mm thickness. (Doubling the thickness makes matters worse. ) The purple line is my own absorber. Developed to produce smooth absorption thru the full base spectrum. Compare these with my super bass absorption panel results in the second image. Designed to deal specifically with fundamental axial modes in small rooms. This passive absorber will deal those difficult 40 to 80 Hz modes. All panels are 550mm * 550mm *90mm deep. They may be wall mounted, free standing, inserted between wall studs or incorporated into room furniture.

A great room. However absorption curtains may be useful further down the track. Suggest that you do phase 2 first. what is the longest dimension in the room? Happy to assist in getting some data together. Just need to use your smartphone. I can email a wav file with some sweeps that will interrogate the room. We would need to make Audio measurements in a number of points in the room. since I retired I’ve developed some Passive absorption technology that may be of use. cheers Kanef