Portable Acoustic Treatments


Expensive but exactly what my room needs. Unfortunately, it appears to be a non-returnable item from the sole US importer. I’m thinking of starting with just one. Thanks for posting the link.

Correction, it is returnable with 5% restock and pay shipping both ways, though they ship for free initially.

I have a eval setup for a pair in late October after the pro audio AES show. I’ll update this once I’ve had some time with them.


hlg3 & Brett66 - After many hours of playing with the REL S3/SHO sub position, level, cross-over… I have come to the conclusion this room is acoustically larger than the physical size indicates. I decided to acoustically measure the room with no sub and just the main Sonus Faber Guareni Evolution speakers. I re-did the John Hunter speaker placement method and got the best bass coupling (by ear), then swept the room with REW software at 0.5in increments, getting the best bass coupling over a 2ft movement forward, rear, left, and right. After arriving at perfect placement, the room is 15-20 dB lower from 20Hz to 80 Hz. Therefore, the room appears a lot larger than the 11ft X 21ft X 10ft physically. In addition, with the S3/SHO pair at max volume they just start to pressurize the room. Therefore, I’m going to move up to the REL 212/SE. These are the subs REL recommends for the SF Guareni Evolution speakers for a grand salon. The 212/SE sub is like having (2) S5/SHO subs in one package with the same 1,000 watt amp as the No. 25 reference sub. I’m going gangster with these subs. These 212/SE subs go to 110dB so I will be able to pressurize the room at a lot lower level than having to max the S3/SHO 350 watt amplifier.


You should read the REL 212/SE review in The Absolute Sound. It details the integration of a pair of 212/SEs in a large room with large full range speakers.

As you are discovering, you have a very large acoustic space because you have large openings to other rooms you cannot close off. The effect of this is heard mostly in bass frequencies. Your ears are not as sensitive to bass and extreme high frequencies because they are tuned to midrange frequencies, think the human voice. This is the science behind a loudness curve. As you listen at more real life volumes the bass can get out of balance, so make sure and use your regular listening levels during setup.

I can tell by your comments and commitment to this effort that you are what some would call a bass hound. I am also. I have had the great privilege of experiencing many reference quality systems in my life, despite never being able to afford equipment of that level. I used to sell and install high end stereo and theatre systems before changing careers in the 90’s. I worked at a retailer that made the investment to have high quality systems in the store, so customers could hear them. I also set systems up in homes and experience the results first hand.

The popularization of home theater and the vast improvements in subwoofer technology have brought good quality bass reproduction to the masses. It is easy to get enough acoustic output today. It is still very difficult to get high quality bass reproduction, as you are finding out.

I frequently took great pleasure in allowing customers to experience sound better than they wanted to afford. The expression on someone’s face when they heard a favorite song on a really good system was priceless. We had a pair of Infinity IRS Beta speakers set up for demo. They were an example of what most folks would call overkill.

When they heard them, they frequently commented on the lack of boom in the bass frequencies. They were hearing, for the first time, what having enough subwoofer meant in a system. You seem to be getting there also.

Let me caution you about getting too tied up with getting flat frequency response when integrating a small set of monitor type speakers with subwoofers in a large room, you will drive yourself crazy. Use the equipment for initial setup or to solve a boom issue as you seem to have. Use your ears, they are the best test instrument you have. Everybody has a different perfect sound. You might find that ultimate flat response is too much bass for your taste, this would not be unusual.

Having enough subwoofer should result in you not noticing them as much. Paul McGowan has said, mid bass, the point between a sub and midrange , might be the most important part, and hardest, part of the system to achieve. This system synergy is what makes subwoofers disappear.

If you ever get the chance make a trip to PS Audio when they get the IRS Vs set up in the new building. I had the privilege of hearing them last summer, and they were magical. It brought back the memories of all the great systems I have experienced.


hlg3 - Thanks for spending the time and responding with good insight from experience. I would not consider myself a bass hound; however, these S3/SHO subs in that room sound like ported subs because I’m having to stick them in the corners to get the proper matched volume of the main speaker and now I’m listening to the bass boom. I have the amps cranked full up and moving them to the center of the room does not help much. I love the SF Guareni Evolution speakers and don’t consider them small bookshelf speakers at all, they are amazing. I have owned KEF reference floor standing, Vanderstien, B&W and these SF speakers are head an shoulders above those speakers. I just want to help them with excellent bass extension. The 212/SE subs will extend bass at 1/3 to 1/2 volume (1,000 watt amp) with a lot of head room to spare. In addition, they are matched to my SF speakers as you have noted; therefore, they will have great mid-bass sound (speed) w/ the SF speakers. The S3/SHO subs are not cutting it at all and were depressing to listen.

PS - I just finished the TAB review with integration into his planar speakers. Best placement John found was inside rear of the main speaker. I believe the 212/SE is the answer. If the room was sealed, going S5/SHO would have done the trick. Also, the suck out at 44 Hz appears to line up with the cross hallway 12.5 ft from the attack wall. This small physical room is very large acoustically. If you read the REL literature on sub selection it makes that note of having a hallway in the rear or room opening up to another room in the back as a bass trap effect.


hlg3 - So, I promised the measurements with the subs moved toward the center (1/3 the way) from the wall. I figured out how to get rid of the 44Hz trough shown in the frequency response above. So, I got to thinking of where I was sitting in relation to the speakers and the rule of 30 degrees from each speaker. So, I measured and found I was in the middle of the cross hallway and sitting 112in from speaker plane with the speakers 91.5 in from one another. Looking at “Y” as 91.5 / 2 in and “X” as 112 inches I was sitting at (degrees(atan(y/x)) ~ 22 degrees. In addition, I was in the middle of the cross hallway. So changed my seating from 112in to 82 inches from the speaker plane and was much closer to 30 degrees. The result was a sound much better so I thought lets measure the difference and below are the results with the XOVER at min & max. The question now is weather I need the 212/SE subs and that is a tough call. One thing for sure, the system sounds much better. Do I really want more base extension…


Strange that the x-over appears to have little effect on freq, only amplitude. I would work to fill in the ‘hole’ from ~60Hz-100Hz. Maybe move the mains closer to a boundary as it appears the subs can’t do it or try the 212/SE.

Your decay time look darn good now. I’m surprised to see this much improvement.


brett66 - If I had set up the system properly to begin with it would have looked better. First, make sure you start at 30 degrees and then move forward and reverse to gain sweet spot. Also, I moved the speakers 1ft at one inch increments in all four directions and this is the best coupling the mains can get. This was very close to the spot after the SUMIKO master speaker placement process. These S3/SHO subs are inadequate at the low end and it also bothered me about the crossover too. In music, I can definitely hear the difference between min, mid, and max. You have to be careful relying solely on the measurements and careful relying solely on the ear. Measurements are not subjective; however, the interpretation and the effect of 5dB may not be as drastic as you think. I don’t know, I just love calculating, analyzing, and engineering this system. It is a just a lot of fun for me. Incidentally, the room has zero acoustic treatments. The next time one of those “acoustic experts” trys talking you into treatments… make sure you measure your room first. I just spent $7,000 on treatments I have to sell. $200 investment in a mic, HDMI to TOSLINK convertor and fiber is worth a lot of money. I just finished designing a P7 & P13 diffuser I can’t wait to build. I’m going with a pair of P13 diffusors on the back wall and a pair of P7 diffusors on the side walls. Going to get this done around Thanksgiving. I will be playing with this system from now till eternity. I just love running thought experiments, analyzing, then executing ideas and measuring. You learn so much about sound when you start measuring. The data is there, you have to figure out “why” and that is the fun part.


I completely agree. I made my own treatments to experiment, and only after liking the results (by ear) did I purchase some nicer made, and lighter weight ones from GIK, but even then only a few hundred $.

At some point, it becomes academic…a hobby in and of itself to measure the response regardless of the audibility of it but it should never take away from the enjoyment of listening.

You started out with a very ambitious goal, don’t forget to smell the roses as they say.


brett66 - I will always play with my system and that is the fun of owning a system like the one I have and an understanding wife. This is just one of a few obsessions I have so every once in a while I get to thinking about whatif…


Very true. But somehow these academic pursuits can be really fun.

We are wonderfully spoiled as we can devote time and resources to such nonsense. :slight_smile:


Elk - Could not agree more. While listening to my system, a big smile comes over my face as my wife walks by the music room and she knows there are very few things in this world that will make me that content. It is all the little things in the world that make you happy. A well recorded song that has amazing texture and 3D imaging. The moment you get the speakers placed just right and settle in with a perfect cup of coffee and a nice stereo magazine to listen to your favorite smooth jazz song. Life just does not get any better… :slight_smile:

After loosing my son at eight years old in a traffic accident, happy is a very hard thing to come by and my system allows me to forget and just enjoy a slice of happy. My wife understands and when she sees that Cheshire cat grin, it is worth every penny I scrounged buying my obsession.

I will be messing with my system till I’m drooling on my self, forgetting who I am… I love the thought experiments and tests and analysis proving you think you know what you are doing till the knowledge boom comes down on you… all good!


Did you put the bass traps back on the floor in the corners as well?

Just curious.



scotte1 - not one peice of acoustic treatment. Sad I spent $7K on a notion that a small room is going to be horrific low end, blah, blah, blah…



Live and learn, I guess.

Got anything good listed for sale yet…?



scottie1 - I just put them on the “for sale” section of the forum. I live in the Phoenix, AZ area and travel to Southern CA in our Range Rover every month. They are brand new and I’d like to sell them.

Traps for Sale:
(6) 3ft ASC 13in diameter “new isothermal” bass traps (silver/grey)
(6) 3ft ASC 16in diameter “new isothermal” bass traps (silver/grey)
(2) wood octagon 13in basses
(2) wood octagon 13in basses



brett66 - OK, so I took the plunge. I just bought the Roon Nucleus+ and iPAD 2017. Here is my new block diagram. I was thinking of keeping it in the great room and just unplugging the P20. Had enough fun w/ data… Then I got to thinking of unplugging the P20 CAT7 cable in the music room and adding the Roon Nucleus+ to one of my rack shelves. This would facilitate getting great power from the P20 and going with the Sbooster or some other linear PS for the Roon Nucleus+ in the future. I’m going to add it in the music room and if there are any issues, will move it to the Great Room. I can’t wait to develop my first convolution filter. In addition, Roon is such a better platform with meta-data and just digging in and learning about source content.


Get a cheap 2TB drive and copy everything you’ve ripped to it. Cheap insurance for your time saved not having to rip them all again…


brett66 - Yes, done that already with a Passport drive. I decided to take advantage of the P20 and place the Roon Nucleus+ on the top of my component rack. I just received my Sbooster 18V-19V MKII LPS and it fits nicely next to the Nucleus+. Powered from the PSA P20 through the Sbooster MKII to the Nucleus+ will be very clean. I’m going to use the 18.0V setting. After digesting the maximum output wattage spec, the 18.0V setting - max wattage = 40.5watts; 19.0V setting - max wattage = 35.15watts. Roon blog indicated NUC715 consuming 29.5watts (linear interpolation) based on 19.0V & 15.0V current measurements. Therefore, I will need as much head room as I can get using the Nucleus+ versus the NUC715 (Nucleus). In addition, I will be using convolution filtering (DSP); therefore, the wattage will definitely exceed the 30watt mark. Based on the Sbooster maximum (conservative) specification, 36.4% more head room using Nucleus+ working DSP. I also rerouted the main speaker cables and got rid of all my acoustic treatments. I will be moving the subs around a little more to get the optimum acoustic response. The iPad (2017) will be arriving tomorrow. The one downside to this reconfiguration of streaming (Roon) is having to loose my iPad III. Roon can’t run w/ iPad III; reason I did not use Roon in the first place. However, after using Mconnect for months; not a fan of that platform. I am not a fan of anything Apple; I hate synchronization and that whole lousy way of handling music. After owning (3) bad Apple music devices, I vowed never to use anything Apple… Oh well, not going to introduce a laptop w/ in the music room. Yes, I know, Roon Nucleus+ is a high powered laptop (i7 dual core w/ 8GB RAM, 128GB SSD, housed in extruded aluminum case; no fans or moving parts) without the noise. I’m connecting the Nucleus+ to my network (100ft away in Great Room) through a CAT7 (great shielding) Ethernet cable with cable toroid at Nucleus+.


Music stores have some great stuff… check it out… you can go to your local Sam Ash or Guitar Center… they have stuff… you can make it look attractive as some come in very neutral colors and you can mix and match… make patterns… get clever.

Bruce in Philly



I’ve had one PSI AVAA C20 eval for a few days now. I simply don’t have the aesthetic freedom to have more than one in the room.

I’m sorry to say but one of them makes a barely perceptible difference in low frequency ringing in my space. I suspect I would need 3 or more to truly tame it, and that of course would be costly.

I used a RF remote power outlet so that I can toggle it off/on from my listening position. The change is so little that I’m often wrong as to whether it’s on or off (the outlet is silent in operation and thus easy to lose track if it’s on or off).