2. misc-audio
  3. 151169-5880

GIK Room Treatment Questions and Advice for Magnepans


     I submitted the following request form recently to GIK Acoustics for a free room analysis.  I want to apologize from the outset that my information establishing the relevant information is so lengthy and extensive, just for a few questions requesting advice at the end, but I thought it was important that readers were aware of all the facts in order to be able to offer the most relevant, specific and meaningful advice.  I'd also like to thank in advance any and all of you that take the time and effort to read this tome and respond.  I'm very appreciative of any advice you're able to offer.
     Okay, here's what I submitted as answers to the GIK form's questions:

 Room Size (width x length x height)?   16' x 23' x 8'
 Is this a dedicated room?   No 
What model of speakers / sub(s) will be used in this room?   Magnepan 2.7QR main speakers, a Magnepan CC3 center channel speaker and a 4-sub Audio Kinesis DEBRA  bass system positioned in a distributed bass array configuration in the room along with a pair of Infinity rear surround sound speakers mounted in the ceiling at the rear of the room. The room is a living room but is used for both 2-ch audio and 5.4 surround sound for HT. My Magnepan 2.7QR main speakers are 6' tall x 2' wide x 2" deep panels that straddle the 65" hdtv and are each positioned about 4' away from the front 16' wall. These and the CC3 center are bi-pole speakers.
Flooring?   Soft surface wall to wall carpeting. 
Are you able to move the location of your set up within your room if needed?   No 
Placement Restrictions?   I have a 65" plasma wall mounted and centered along the front 16' wall, with the center of the flat screen about 38" from the floor so it's at eye level at my viewing/listening seat centered on the rear 16' wall. The CC3 center ch spkr is mounted on a tv wall mount that places the speaker centered just above and even with the front plane of the 65" plasma hdtv screen. Both the hdtv and CC3 are extended about 32" away from the front 16' wall on their wall mounts. There's a 6' high and 8' long window centered on the left 23' wall that is covered with an equal sized plantation blinds window treatment with 1" horizontal slats.
There are two 5' wide openings to this room, one located along the rear 16' wall just in back and to the left of my listening chair as I'm seated in it (this leads to my home's front door foyer) and the other opening is located along the front of the right 23' wall that begins about 2' away from the front 16' wall (this leads to a large dining room).
There's also a 3' tall x 2' wide mirror hung and centered above my leather listening/viewing chair on the 16' rear wall behind it. I'm willing to remove this if you determine diffusion or absorption panels would function better on the rear wall directly behind my chair. 



     Here's the GIK rep's recommendation I received in response:

"I agree that with Magnepans diffusion of some sort is helpful on the front wall. While I’d love to throw a wall of Gothams up there, it would destroy the budget and leave too much other stuff untreated.
I think we should use the Alpha Series for a majority of the treatment because they provide both diffusion and deep absorption so we can solve both problems simultaneously. Based on what I could gather from your description we can at least treat the corners and front wall behind the speakers. It seems like there’s space behind the TV and center channel so bass treatment back there is helpful too, but I’m pretty sure our budget will limit our ability to do that.
The back wall would also benefit from a similar approach and I would absolutely recommend you remove the mirror from behind your chair.
I think I’ll give you a plan that covers more area that is well over your budget, but you can do some now and some later. That way you have a plan that gives you a more complete room that you can aim for down the road.

Here’s what I recommend for a fairly complete room:
4 -CT Alpha Series Corner Bass Trap with 2D Scattering @ $210.00 two in each front corner stacked for bass treatment and diffusion 5 -244 Bass Trap w/FRT (24”x 48” rectangle) Full Range @ $74.99 on the left wall next to the window to offset the archway on the other side and four mounted evenly across the ceiling. 2 -4A Alpha Series Bass Trap Diffusor/Absorber (Rectangle) with 2D Scattering @ $138.00 on the front wall one behind each speaker for diffusion and absorption 3 -6A Alpha Series Rectangle with 2D Scattering @ $198.00 on the back wall behind your chair for diffusion and bass absorption.
Total for all: $2084.95 plus shipping. It doesn’t address the sidewalls much but with the archway and the window, I don’t know that there’s much other space to treat there anyway." 


     Okay, here are my thoughts and questions for those intrepid souls that made it this far:

1.  I'm not going to purchase all of GIK's recommended room treatments for $2,085. I'd prefer to purchase those treatments that you and I believe will improve my room acoustics the most on a budget of about $1,000 initially with more to be purchased in the near future, after I have a chance to install and evaluate the results of the initial treatments purchased.
     In particular, I don't think any of the following are necessary or will be of benefit in my room: the 4 -CT Alpha Series Corner Bass Trap with 2D Scattering @ $210.00 two in each front corner stacked for bass treatment and diffusion 5 -244 Bass Trap w/FRT (24”x 48” rectangle) Full Range @ $74.99 on the left wall next to the window to offset the archway on the other side and four mounted evenly across the ceiling.  My reasoning is that my AK DEBRA 4-sub distributed bass array system currently provides extremely good bass performance in my room down to about 20 Hz along with the bass blending  very well with my main speakers throughout my entire room with absolutely zero room treatments being currently utilized.  I'm mainly concerned that any added room treatments functioning as a bass trap would only have negative effects on the bass in my room.    

     Does anyone think using treatments that include bass trapping would be of any benefit in a room in which the bass is already considered extremely good?  If so, what benefits would be perceived?


2.  I'm thinking it would be best to use 2D diffusing treatments on both front and back 16' short walls in my room; meaning behind each dipole Magnepan on the front wall, the space above my flat panel hdtv and between my main speakers on the front wall and behind my listening seat that is centered on the rear wall.

     Do you agree that placing a 23" x 45.5" rectangular 4A Alpha Series Bass Trap that also diffuses behind each Magnepan and smaller 2' x 2' square 4A Alpha Series Bass Trap that also diffuses behind my listening chair and above my hdtv and between my main speakers woul be a good solution?

     Or, do you think one of these diffusers would be better behind each Magnepan?
https://www.gikacoustics.com/product/evolution-polyfusor-diffusor-absorber-bass-trap/

https://www.gikacoustics.com/product/gik-acoustics-q7d-diffusor/

    I'd also like to know if you think 2' x 2' square absorption treatments would be best behind my listening seat and possibly above my hdtv like these?

https://www.gikacoustics.com/product/gik-acoustics-242-acoustic-panel/



Thank you for any advice you care to offer,
                     Tim
128x128noble100
noble100's avatar
noble100 OP
2,419 posts
 
Hello brownsfan,

Browns looked good pounding the Jets. And yes, I did buy your old house and yes, I did find that hidden dungeon room you built in the basement. Talk about room treatments, that thing is soundproof! It’s now my kids’ new playroom, thanks.
My system doesn’t really have any major issues, overall it sounds very good. I’m mainly interested in achieving a very palpable, 3D presentation that makes it seem like the musicians are in the room or I’ve been transported to the musical venue. I currently only have this experience on some select very good recordings.

I’m using an 18 TB NAS containing about 20K albums, about half are FLAC ripped CD files and half are hi-rez FLAC and WAV files that range from 24bit/96KHz to DSD and I’m using a Lumin D2 to stream these files. I was thinking I have a decent enough system and enough well recorded music recorded at a high enough resolution that the ’you’re in the room’ quality playback should  be a more common occurrence.
My main goal for investing in improving my room’s acoustics is to have more of my music collection provide this ’in the room’ perception. I’m thinking better room acoustics is likely a good method of achieving this. I really enjoy the somewhat elusive experience of a solid and stable 3D soundstage where everything seems and sounds so dynamic, palpable, immediate and real.


Hello larryi and tep,

I agree with you both about approaching room treatments incrementally along with not wanting to over dampen the room through absorption. I’ve been learning that utilizing panels that diffuse or scatter the midrange and treble frequencies while also absorbing the bass below a specified frequency may be the best solution for my dipole speakers and room.
The bass in my room, thanks to deploying four 10" subs in a distributed bass array system, is currently extremely good and I believe there’s still no need for any bass traps in my room. 
     But I understand that excessive upper bass in a room can mask and negatively effect the important midrange frequencies. I don't hear any excessive bass at any frequencies.  However, I've also never ran a spectrum analysis in my room and it's technically possible there's some bass issues effecting higher frequencies that I'm not even aware of.  Therefore, I'm hoping a bit of upper bass trapping built-in to some of the newer GIK acoustic diffusor panels won't change my perception that the bass is extremely good in my system/room but, if there are issues, this damping may even improve the sound quality overall.  I'm doubtful but realize sometimes you just don't know what you don't know. I'll just call 'em like I hear 'em.
     So, I’m currently planning on starting with the following:
Two -4A Alpha Series Bass Trap Diffusor/Absorber )33"x48.5"x2"Rectangle) with 2D Scattering on the front wall one behind each main speaker for diffusion and absorption.
Six--4A Alpha Series Bass Trap Diffusor/Absorber (24"x24"x2" Square) with 2D Scattering, 3 on the front wall above my tv and between my main speakers and 3 on the back wall directly behind my listening chair, all for diffusion and absorption.

I think this is a good targeted quantity to begin with. I’ll audition the results with these and proceed from there.


Thanks you guys,
Tim
three_easy_payments's avatar
three_easy_payments
2,097 posts
 
yep, according to the guys at Arqen Sonic here are the Three Golden Rules for treating small (e.g., domestic sized) rooms:

  1. Add broadband bass traps to as many corners as feasible, including the wall-ceiling corners.
  2. Add mid/high frequency absorption at the first reflection points on the sidewalls and ceiling.
  3. To prevent flutter/slap echo, add some mid/high frequency absorption and/or diffusion to any large areas of bare parallel surfaces. E.g., parallel walls, parallel ceiling and floor.

This my basic approach.  Haven't gotten to the ceiling yet.

brownsfan
1,508 posts
 
@noble100,  
I took a look at your member info and found you live in Noblesville.  Funny, my old house was in Castleton.   We moved to Tennessee for retirement in 2014.  Nice seeing the Browns actually win a game every once in a while.  Its been awhile.  

I have two other questions.  
How far off the back wall is your sofa?
Do you perceive a drop in SPL on the side with the 5' opening?

I would emphasize again the importance of utilizing the REW software (free download) as a guide while you are evaluating your starting point.  Again, in a room like yours, making sure you get your decay times below 300-400 milliseconds in the vocal range is very important. Also, dipoles are less predictable because of the back wave and because first and second reflection points on side walls can be less problematic than with dynamic speakers.  The software is free.  The only expense would be in buying an SPL meter or microphone. 

I'm inclined to think that after you manage (if necessary) low frequency decay times the next most important area to treat is the back wall.   Side wall early reflections may or may not be contributing to image degradation, but back wall early reflection almost certainly is.   I'd be inclined to go with diffusion on the back wall if your seat is far enough away from the wall for a diffusor to work.  If not, then judicious use of absorption can help as long as you don't add so much that you deaden the sound.  I used GIK soffit traps with range limitation so that I didn't suck too much of the mid and high frequency out of the room.   If you use broadband traps, be careful how much you introduce.  One too many traps and a room can really go dead. 




noble100's avatar
noble100 OP
2,419 posts
 
Hello TEP,

Good info, thanks.

1. Broadband bass trapping always concerns me and makes me hesitant to even try it in my room. As I’ve stated, I use an Audio Kinesis DEBRA 4-sub distributed bass array that performs incredibly well in my room.
I honestly cannot think of any aspect of the bass performance in my system/room that needs improvement.
     Because of this, I’m very reluctant to introduce any room treatments, even ones as conventional and traditional as bass traps, that might negatively effect the current very high quality bass performance I’ve been enjoying in my system and room. I decided not to purchase any of the GIK corner bass traps and purely bass trapping panels suggested in their analysis of my room.
     However, I am going to soon order and utilize some GIK Alpha Series Bass Trap Diffusor/Absorber panels of various sizes for my front and back 16’ walls. These are mainly intended for the purposes of increasing diffusion in my room but they also contain elements designed to absorb frequencies from the mid-bass to the mid-treble. I’m a bit concerned that even these could negatively effect the bass performance in my room.


2. Mid and high frequency absorption at the first reflection points on the sidewalls and ceiling is something that makes perfect sense to me, making sure the direct sound from the speakers and the reflected sound don’t arrive at the listening position too closely together time wise. However, my right front Magnepan panel is positioned directly across from the beginning of a 5’ wide opening on the 23’ long right wall in my room that leads to the dining room beyond. And my left front Magnepan panel is positioned directly across from the beginning of a 6’ high x8’ long window section, completely covered by plantation blinds that are about an inch wide, along the 23’ long left wall in my room.
     So, there’s no first refection point on my right wall and the first reflection point on my left wall is on a plantation blind covering a window, which is difficult to absorb. I’ve been leaving the 1" thick horizontal blinds open, when seriously listening to music, reasoning that the open blinds act as an acoustic diffusing panel in my room.
     Of course, I can’t be certain early reflections are being sufficiently delayed through this method. I’m thinking I’ll have my wife hold up one of the 23"x48.5" Bass Trap Diffusor/Absorber panels at this point to determine whether that results in a soundstage improvement. But if it does, I doubt she’ll be willing to do this for hours at a time. Any ideas?
     For the ceiling, I think I’ll follow your lead and get to that later. I also believe my Magnepan planar-magnetic speakers’ radiation pattern directs very little to no sound energy towards the ceiling.

3. I do have two 23’ long parallel walls but the left wall has a 6’ high x 8’ long window in the middle of it completely covered by wide plantation blinds and the right wall only has a few bare sections. Both you and the GIK analyst suggested diffusion or absorption may be beneficial on these walls so I’m going to experiment a bit with both on these surfaces.


Thanks for your help,
         Tim



gammonit_2000
83 posts
 
I set up my Magnepan LRS in my LR/DR space today, and my mind is blown how well I did.  The carpet in front of the speakers that is thick seems to work in terms of not reflecting off the hardwood floors, while spreading out the sound in front.  I set the speakers in a "knock out" area so the bass is great as there is a 4ft. coat closet on the left, and the corner on the right.  I actually have them closer to the closet than the corner.  They fire to the back wall into tall very filmy curtains.  Anyway I can literally walk everywhere and it's all a freaking sweet spot. Behind the sound is consistent from left to right, walking around the speakers it is still sweet.  In front a ways away it is a little louder but no better in quality.  These speakers like the Bryston 4BSST amp and BP20 preamp.
More to discover