SMT Wing Diffusors vs. QRD Diffusors? Effective?
- Thread starter caesar
- Start date
In the video there is a device that looks like it is on the floor next to the Varitune panel that is being lowered. What is that and why is it taking a measurement from that location and not from the listening seat?
It is the main problem with this type of devices for bass treatment. You need a considerable number of them to effectively tune a room and IMHO they are not nice to see. YMMV.
Hallo!
Ok, I understand. The device is a SPL meter and to tune a Varitune you do as describe in the video. In front of the port you schould have as flat freq response as possible. You are running a pink noise thru the speakers as one can hear in the video. In the video(I was not involved in this measurement)they are just describing what is happening when adjusting a Varitune.
In my link in your thread, I am showing at my LP. I did the same measurement in front of all of my Varitunes as describe in the video. That time I did it with my ARTA program. Now I use my dbx260 where I have true SPL meter that I use to tune my Varitunes. When I measure and tune the right side Varitune(for example) I only run the left speaker, when I tune and measure the Varitune between speakers I use both speakers. The more Varitune you have the better it will be in the freq response at LP and at the same time the resonances in the room will be less and less and even out. The Burst Decay in ARTA comes very handy to see this.
In my provided link in your thread, It's a pity I don't have these measurements left when I had my room empty. When I did the measurement in all of my corners without any treatments in the room I had Peak at 30Hz, Suckout at 50-60Hz, Peak at 80Hz. The interesting thing is that the three Varitunes(V4) left(above V6), middle(underTV) and right(above V6), as show in the picture in my link, was tuned at around 55Hz, namly a suckout in the corners. Go figure!
Hope it cleared it up a little bit....
Edit...I forgot to mention that a Varitune is a Phase shifter as well.
Last edited:
Hallo!
It depends, about how many. I have seen great result with only two V6 in a small room.
Hallo!
It depends, about how many. I have seen great result with only two V6 in a small room.
Thanks. I have read somewhere that we can get Varitunes in a DIY flat type pack. Any truth in it?
BTW, I am having a great time reading the thread about your room in the gearslutz forum https://www.gearslutz.com/board/bass-traps-acoustic-panels-foam-etc/651132-my-room.html - most probably some of our readers will also appreciate it.
Though I sell acoustic products, there are a few things worth mentioning.
Common diffusers are based on BEM simulations and this is widely recognized in the industry. The SMT diffusers do not use BEM simulations but CATT simulations. No one else in the industry, at least that I'm aware of, believe it's possible to design diffusers that way. In other words, the SMT products may not be diffusers by the strict definition but more a kind of scattering unit. Difficult to say before there are independent measurements.
There are different types of QRD diffusers. Some withthout fractals and some with. The use of fractals creates a broadband diffuser that can diffuse all the way till 20KHz, while standard diffusers stop around 4KHz. This makes a huge difference. Some QRD diffusers like RPG's Modffusor and Modffractal are based on an aperiodic model, thus minimizing lobing greatly and creating a much more homegenous diffuse field when several units are used together.
I had heard Flyer's system before, which is full of SMT treatment, and Flyer had mentioned that the regular audiophile does not need so many wings - 1 behind each speaker, 1 behind but in the centre, at first reflection points, and on the ceiling are sufficient. This is exactly what I got to demo at Jazzhead's place in Mumbai last week.
His Marten Coltrane 3, powered by Vitus class A amp and Wavac PRT 1, are in a room that though long (25ft) is narrow (11 feet). He has made the best of his room though by pulling the speakers out a fair distance from the wall, and placing the SMT wings behind them, 1 behind each speaker and 1 behind but in the center. We are able to AB with and without. He also has first reflection points fixed to the walls that cannot be ABed, but then he has 1 wing on the floor in front of each speaker, raised up at a slight incline towards the speaker, and this could be easily ABed.
During each AB, there was a significant drop in soundstage, 3d, flow, and focus. With them in, the room seemed bigger and the bass and stage behind the speakers had a nice depth.
At flyer's place I had ABed the wings behind the listener, and at Elberoth's I had ABed a pair at first reflection points. Given the aesthetics of the wings, I am quite convinced by them as a product and will look for wings at key positions once my new room and speakers are ready.
His Marten Coltrane 3, powered by Vitus class A amp and Wavac PRT 1, are in a room that though long (25ft) is narrow (11 feet). He has made the best of his room though by pulling the speakers out a fair distance from the wall, and placing the SMT wings behind them, 1 behind each speaker and 1 behind but in the center. We are able to AB with and without. He also has first reflection points fixed to the walls that cannot be ABed, but then he has 1 wing on the floor in front of each speaker, raised up at a slight incline towards the speaker, and this could be easily ABed.
During each AB, there was a significant drop in soundstage, 3d, flow, and focus. With them in, the room seemed bigger and the bass and stage behind the speakers had a nice depth.
At flyer's place I had ABed the wings behind the listener, and at Elberoth's I had ABed a pair at first reflection points. Given the aesthetics of the wings, I am quite convinced by them as a product and will look for wings at key positions once my new room and speakers are ready.
Hi Björn, the proof in the pudding is in the eating.
I don't know if you have seen the wings already in real life because if you have, i don't think you would be comparing them to (fractal) QRD diffusors. When looking at the pictures in the link that Caesar forwarded, you may be deducting that the wings are QRD type but they aren't since their back is not only open but connected to each other. Check the transparent mobile V-wing drawing, you will see that each 'entry gate' has an opposing 'exit gate'.
The S-wing has a bit of a different design, actually a more complex system of 'connecting vases' once the wave has entered but in the end all 'gates' are connected. This has several beneficial effects that ultimately have to be heard to be believed. After all, it is not abnormal that a new product that says to have a novel approach has an impact not known till then. It just shows the research paid off.
Finally, I am as well a fan of more exact approach and used to love to see measurements. But if you put several manufacturers next to another, you will quickly notice there are a big number of norms being used (ISO, ASTM, AES, ...) and they cannot necessarily be compared although each manufacturer claims it is 'the norm'.
I cannot resist to think that some manufacturers even put forward norms of which they know they cannot be compared to peer companies... so yes, they have plenty (or some) measurements but if you are not sure you compare fruit with fruit it is just window dressing.
But, on a positive note again, I wish the RPG test protocol and documentation for its products would be used more widely across the industry! Though it is not applicable to the SMT wings as the effects of the latter would only partially be laid bare in such test due to their different functioning, but this is just an opinion of mine.
I have both seen them and heard the result in many rooms. And after that I've even more convinced that they are not diffusers but simple scattering units without an even distribution and where the result is frequencies that sticks out in a negative way. That's what both I'm hearing and my friends who have also been in room with these products. Neither of them had any bias or knew anything about the products before they walked into the rooms but commented the same thing. I don't know if I've ever heard so many high gain specular reflections from a setup with so much treatment as the one below. The opposite would be the case if the treatment worked properly.
The idea that the sound will pass into the tunnels and distribute frequencies in an evenly way, which is required for it to be called a diffuser, is dubious. What you get here is probably a little delay only for certain frequencies and also high gain reflections from the surface of the unit. Many of the higher frequencies will hit the surface directly causing both specular reflections and diffraction.
Sorry, but I don't believe these products are proper acoustic products. And while I understand people would question me since I'm a retailer of RPG products I can honestly say I wouldn't have a problem recommending them if I knew they were well designed products. SMT can prove me wrong by offering real measurements of the products, following the standards in the industry.
The idea that the sound will pass into the tunnels and distribute frequencies in an evenly way, which is required for it to be called a diffuser, is dubious. What you get here is probably a little delay only for certain frequencies and also high gain reflections from the surface of the unit. Many of the higher frequencies will hit the surface directly causing both specular reflections and diffraction.
Sorry, but I don't believe these products are proper acoustic products. And while I understand people would question me since I'm a retailer of RPG products I can honestly say I wouldn't have a problem recommending them if I knew they were well designed products. SMT can prove me wrong by offering real measurements of the products, following the standards in the industry.
Hallo!
You are right, they are not diffusers rather "Time Delays Lines". Better than diffusers
This you have to prove "And after that I've even more convinced that they are not diffusers but simple scattering units without an even distribution and where the result is frequencies that sticks out in a negative way."
And, there is NO measurments that I have seen in a real room presented by RPG product's. Full freq band, waterfalls graphs and sliced ETC curves, nearfied measurement in small rooms.
And yes, you are only a seller and a retailer of RPG products.
Last edited:
Here is some measurements with the flower wings on the floor.
In two separate rooms....
https://www.gearslutz.com/board/9455716-post166.html
https://www.gearslutz.com/board/9455764-post168.html
This is an old mesurements, it is so much better now with the s-paper wings cover the sidewalls.
https://www.gearslutz.com/board/9664574-post183.html
There excist no scattering in wings modules.
In two separate rooms....
https://www.gearslutz.com/board/9455716-post166.html
https://www.gearslutz.com/board/9455764-post168.html
This is an old mesurements, it is so much better now with the s-paper wings cover the sidewalls.
https://www.gearslutz.com/board/9664574-post183.html
There excist no scattering in wings modules.
JBL Cinema Screen Array's 3731 Bi-amp mode and two 4641 Subs with three Crown MA5000i amps.
Yes, it is a two channel system.
Last edited:
Hallo!
What is that on the floor??, must be something here you are hearing the high gain specular reflections. Looks like they have put something to cover the carpet.
Last edited:
Björn,
You forgot to mention that lots of Scandinavian forum members rewarded Marten show set up with best sound. Good reviews from Sven Bilen Nomono, also, SMT Wings had also best in show one week earlier Hamburg Norddeutsche HiFitage.
www.facebook.com/audiorefinement/?fref=photo
You forgot to mention that lots of Scandinavian forum members rewarded Marten show set up with best sound. Good reviews from Sven Bilen Nomono, also, SMT Wings had also best in show one week earlier Hamburg Norddeutsche HiFitage.
www.facebook.com/audiorefinement/?fref=photo
Hi Björn, if I read your sentence right, then if SMT were to provide you 'real measurements, following the standards in the industry', you would be willing to recommend the product. I guess you must be thinking RPG has the 'standards of the industry', so you think no other brand is giving real measurements and hence you discard them all...
On the other hand you hammered a few posts earlier on how poor sounding the SMT products are in your opinion.
I can't believe you wrote that to be honest: if I was as negative as you were on the sonic effects, I would not recommend the product, whichever way the measurements look like!
You disclosed earlier that that you are an RPG-dealer which is positive, what is much less so is that you are trying to prove that in any way you can.
As an SMT dealer myself in Belgium (having had plenty of Schroeder panels myself) I can only strongly disagree with what you describe must be the effects of the wings.
For me "the proof of the pudding is in the eating" by hearing the treatment. Not so for everyone I know now.
Similar threads
