Soundman2020 - Studio Design Forum

Hello all, hopefully this isn't too long but bear with me.
Here is my .mdat file if you want to get right into things which hopefully i calibrated correctly.

It has sweeps with room empty, then with modular superchunk traps on the ground and then with the remaining panels leaning on the walls nothing hung at reflection points yet.

INTRO:
I've been through this process a few times, getting into treating an imperfect space little by little, building panels and getting better at understanding REW, but I've yet to post on the new forum. It always takes much longer than i think, and eventually we have to move.
This time because we needed more space with our new baby girl. Since she doesn't need a room quite yet I'm commandeering our second bedroom for my production space/mixing room.

The bedroom is pretty symmetrical/ rectangular however, it's also quite a bit smaller than my last living room apartment studio. I think I'll do better though here in the bedroom with less distraction/ more privacy to record as my new living room is not very practical for a setup.

Bedroom measures 10.3 ft wide x 18.5 ft to the back of the closet wall x 8ft ceiling (95" actually, which creates a problem due to my existing traps height) already removed closet doors, and considering whether or not to remove the closet clothing shelf/rail. This is a rental and I will have to put it back eventually and in the meantime store it somewhere so hopefully i can just leave it up, open to suggestions though based on the required treatment.
Photos:



Current state of things



Based on initial measurements, I am thinking i need a lot more bass trapping in this room than i did at my old space, unfortunately my modular superchunks with a 23" face don't quite fit stacked here the way they did in the old apartment, unfortunately I'm just shy an inch of ceiling clearance. I think 23" wide face isn't big enough for this room anyway, but i can still use them in other places.
Two Photos from my old apartment



Current traps available all made from Roxul AFB
8 - Modular superchunks 23" face
6 - Broadband panels 2' x 4' x 4" thick with 4.5" wide wood frame.
(Sides of frame were made mostly hollow with a with a jigsaw.)

1 - 3' x 5' ceiling cloud 4" thick with 4.5" frame sides hole sawn out


Just brought home 4 packs of 16" safe and sound. Would prefer the 24" for ease, but it seems all the insulation suppliers nearby are back ordered. Can't believe i managed to fit all this in the back of my wife's Subaru Outback, didn't even have to use the roof rack, hopefully this will get my new ceiling cloud and some of the super chunks started.


Current Plan:
Ceiling
Hang the modular superchunk traps in ceiling/wall corners where i am able to fit them.
Thinking:
2 on the left side wall (door frame prevents clearance for the 3rd)
3 on the right side wall
1 at the front above window
1 at the rear wall in closet
1 on the floor at the rear or front wall(not sure which is best.)

I cant hang two of these traps between the new super chunks as the 24" side lengths of the new superchunks doesn't leave enough space. For symmetry I could put one on the floor at both front and rear and if that is better than 3 on the right hand wall.(would get in the way of a storage chest i was planning on putting in the closet though.)

After reading more, I think I will build a 6' length x 4' width x 6" deep ceiling cloud, with the sides open either hole sawn or perhaps to avoid cutting a hundred holes i may build a skeleton frame out of 1x3 if i can get it sturdy enough.

I found that Stuart usually suggests a hard backed cloud, not sure why though, would love some info on that, as i didn't know that when i made my first cloud.

I bought some 5/8" MDF it is cut into 3 - 2' x4' sheets (so i could get it home) which should cover the entire rear of the cloud, also making the cloud a heavy beast, hopefully its thick enough, 3/4" MDF seemed way too heavy but i can always get some if it makes a big difference.
Once i build that, I can use the smaller cloud maybe mounted adjacent to the new one to elongate the mix cloud or somewhere in the rear of the room, open to ideas on what's best for this.

Corners
4 - 36" faced superchunks floor to ceiling at the front and rear corners of the room.
The closet rack is an obstacle but i can build around it, unless there's a good reason to remove it. I was thinking i could hang curtains and still use the closet for a little storage.
Rear wall
3 - existing 2' x 4' x 4" panels to fit between the the two superchunks and i may build/mount more traps to fill the remaining wall space above the closet shelf. 3 panels between the super chunks should fill the wall between the super chunks perfectly.

Currently building
2 - 2' x 2' by 4" thick absorbers for behind the speakers.
2 more - 2' x 4' x 4" broadband traps with the frames hole sawn
i have these frames already cut same as my existing traps. Using 1"x5" which is 4.5" wide.

Side wall reflections
Was going to place 2 of my 4" thick broadband traps at each side wall for the first reflections.
I suppose i could instead make 6" thick side wall absrobers for the first refelction points on the side walls if needed, then i lose a foot of space though in the room, opposed to 8 inches.

I am open to any suggestions especially would like to know if there is a better way to move forward. I'm still not exactly certain how to diagnose my room on the .mdat file although i can see where there are issues. Mostly my acoustic knowledge is limited to building bass traps and first reflections. I'm sure once i install the new corner superchunks and take a new measurement that will determine if i even need to hang all of the smaller modular superchunks, but i'm assuming i will need all i can get.

Any input is greatly appreciated.

In your shoes, before I did anything else, I'd empty out the room then fill that entire rear wall closet with low density insulation. Whatever your local equivalent of loft roll would probably do. From bottom to top, side to side, to its full depth. How deep is it by the way?

As far as I know you can keep the shelf, it would be useful as low density insulation piled that high will tend to compress itself over time, The shelf will reduce this. Once you are happy with it, make a light frame covering the whole lot and cover it in fabric.

A deep low density bass trap of this kind at the rear of the room will give a massive improvement, all the way down to the lowest frequencies. Value for money & effort with this is huge, perhaps the best you'll get for the entire treatment process.

Once it's done, measure again and take it from there. You might not even need corner traps at the rear of the room in front of the closet.

Cheers!
Jennifer

Hey thanks for the reply Jennifer!

I appreciate you taking the time. I definitely considered doing that, but i was hoping that the 35" faced superchunks in 4 corners would be enough for additional bass trapping in addition to the smaller superchunks i already have, was hoping someone more versed might be able to take a look at my REW and make an assessment based on that.

I was doing some reading and can't really find a definitive answer on how low My super chunks will absorb though. One thing that threw me off in my .mdat file is the peak at 33hz. I'm not sure how the physics work, but i think my Yamaha HS80m's frequency range was only down to 46hz, so I'm assuming this has to do with a room mode being excited in the sweep?

I already removed the closet shelf in anticipation of building the super chunks, no big deal. I reckon it would take about 6 rolls of the fluffy Insulation to fill the entire closet which is 25" deep, I can get another 4-5 inches or so at the door frame if its worth doing. And the roll comes 25' long x 23" wide x 9.25" thick, so hopefully one 23" deep stack wall to wall floor to ceiling is all I'd need for ease of installation. I can possible hang a layer vertically in front of the first stack to fill the cavity but it would compress a little, or i could just hang my broadband traps in front of it as well. I would definitely build some support shelving out of 2"x2" and thin plywood to help with the compression. So at $50 or so a roll plus some wood maybe about $360ish to go this route.

I currently already have enough Roxul insulation for the superchunks, but i could repurpose some of it to make the new cloud instead.
One reason i was leaning toward superchunks is that it just seems like an awful lot of insulation to bring into the apartment, although i guess i could roll it back up and save it when i move out. It also would remove the option of any storage in the closet for micstands/cases and what not. Which is fine with me, if it really is the best method.

I was also learning more about "hanger bass traps" and came across this sketchup that John posted on this thread.
http://johnlsayers.com/phpBB2/viewtopic ... anger+trap



Based on the drawing these only protrude about 1 ft off the wall, while it would be much more work to install i think it would be a little neater and less messy. Maybe I'm wrong though. I just don't know how it would compare in effectiveness to filling the closet with fluffy. Any ideas here?

Otherwise I'm wondering if I might be able to start with the superchunks as I'm already in the process/ have the materials. Then maybe if I still have a huge low end problem, perhaps there is a tuned trap I could build and hang on the rear wall, I'm pretty handy and enjoy learning more about the construction and implementation of these devices.

I would assume this is something that kind of takes some experimentation to know for sure, but I am trying to go for the neatest best looking setup that uses the least amount of space if possible. Appreciate any input, and thank you in advance to anyone who takes the time to read and reply.

victorr_sun wrote:Source of the post... fill the entire closet which is 25" deep, I can get another 4-5 inches or so at the door frame if its worth doing.

I was also learning more about "hanger bass traps" ... Any ideas here?

I had a 27" deep rear wall bass trap using hangers (which were actually stands in my case) in my last place. You might like to look at posts 33 and 35 in the topic 2nd room in Slovakia on gearspace.com.

I put your room measurements into the Amroc Room Mode Calculator and it confirms a modal peak around 30Hz, so your assessment of the 33Hz peak being caused by room modes appears very likely.

https://amcoustics.com/tools/amroc?l=18 ... ing%20room

The speakers being in the corners will also give a bass boost. Once treatment is finished you may find it useful to apply a low frequency rolloff to compensate for this.

I believe Stuart suggests a hard back cloud at the angled part only to reflect low frequencies away from the mix position as part of the RFZ (reflection free zone) approach. Presumably those frequencies are low enough that they would not be completely absorbed by the insulation.

As Starlight mentions, I've heard good things about the rear wall hangers too, and would certainly have considered using them in my place if there had been space to do so. Most of these applications seem to recommend around 2 feet or greater depth also.

Your closet would have enough depth for low density absorption or hangers. If you go with low density absorption don't cover the face of it with higher density absorption or you'll reduce the entire rear trap effectiveness. What happens is the higher density absorption reflects some sound back into the room before it hits the low density insulation.

One great feature of the low density absorption is how easy it is to try out. Buy your insulation rolls and as a trial pile them up in the closet without any wooden structure, fabric cover or what have you. Do before and after tests, then make an assessment on how to proceed. If you like the results, stick with the plan and augment the rest of the room accordingly. If it isn't sufficient, try something else. I suspect the hangers will offer even better results but have not verified this myself.

Perhaps this comes across as a bit cavalier to be suggesting an experiment that could potentially end up wasting $300 of your money, but it's an experiment I would personally do in a heartbeat. I spent far more money on less useful things on the way to discovering just how good these whole rear wall traps are

Oddly enough this type of loft roll seems much cheaper here in the UK. I probably paid about $20 per roll. Quite unusual that. Perhaps worth shopping around a bit?

I posted some results of my own experience with this. Even a partial height low density rear wall trap gave results I couldn't get close to with any amount of standard 4x2' traps. Right down to the very low frequencies. Posts 298 to 300; https://www.digistar.cl/Forum/viewtopic ... 3916#p3916

Cheers!
Jennifer

Alright it’s been a few weeks, but I decided to try my hand at making some hangers. I don’t know if I made the right decision but I tend to like a challenge.

I can tell you I spent way more than $300 dollars though and hours more in labor of course. Still in the process.

I’m hoping for the best although my design for hangers isn’t as deep as the closet would be if I filled it with fluffy. I did 16” deep, and about 7ft tall.
Chose this for portability, as I’m mostly doing the work myself, and have to carry each hanger from my garage to the upstairs bedroom, and eventually will have to move them all again when I move. 16” panels seemed more manageable, and it’s the only size in stock in my area. At least till November.

I was initially looking for fluffy loft roll, to use as I read that it’s cheaper and might not really matter the density. Unfortunately no one sells thin 2 inch fluffy near me. Or it would have to be special order. So I picked up some 3” thick roxul AFB, as they also didn’t have 2” in stock.

I decided to take the tedious task of slicing each sheet in the middle to get a rough 1.5” thick sheet.
Not sure I’d recommend, it’s was hard to get an evenly cut sheet as my electric turkey carver wasn’t long enough to go through the sheet in one pass.

So the panels are a bit rough with some thinner or thicker areas throughout. I figured having more thinner panels would be better and easier to move. Hard to find an exact answer on the subject.

I’ve been sort of documenting the process with pics and videos, might put together a YouTube video if they turn out to be a success.

Making 25 hangers to fit the closet, I thought about angling them, but it seemed like it would be a big pain in the ass and I’d fit less of them, or I’d need to make them in different sizes to fill the space.

Here’s some pics so far.




I strapped some 2x4 to the ceiling joist and wall top plate, itll probably be roughly 350lbs hanging from one joist and the wall top plate so I might brace the joist with a 2x4 from the floor to ceiling, just to make sure the ceiling drywall doesn’t bow at all. I feel like it’ll be fine, but couldn’t hurt.

I think im just gonna frame and wrap the closet entry, after all, which makes me think it might have just been easier to fill it with fluffy haha. But I liked the idea of learning something new.

Anyway I was wondering what if anything I can use to fill the gap. Can I mount my 4” broadband traps in front of the hangers? Or would that defeat the purpose? I think I’ve seen people do that when soffit mounting their speakers. What if I leave some empty airspace around the 4” panels in front of the hangers, like so there is an open port of entry around the sides of the panels into the closet if that makes sense. Any ideas?

Once I finish up and test the response I’ll have a better idea of what to do. Stoked to see how well they work hopefully I can finish up this weekend.

Nice one.

A couple of observations based purely on reading about these as I haven't built any hangers yet myself;

I think they should be angled. I gather one of the major benefits is that sound hits them at an angle and "bounces" about among the hangers, adding to the absorption effect.

All the designs I've seen have insulation attached to the rear and side walls, and probably ceiling behind / to the side / and above the hangers. So sound that gets through the hangers and reaches the walls is absorbed more instead of being reflected back.

It's definitely not a good idea to put high or medium density insulation in front of a deep fluffy absorber because it reflects back a load of sound before it hits the fluffy. I suspect the same may be the case for the hangers.

Cheers!
Jennifer

endorka wrote:Source of the postI think they should be angled ... rear and side walls, and ... ceiling ...

I believe so, too.

Wow, it's been about a month and a half or two that I've been working on this project. Thought it would be lot easier but learning as i go and have learned so much more than when I began.

Found this thread and followed Stuarts advice:
;https://www.johnlsayers.com/phpBB2/viewtopic.php?f=2&t=12365&start=120

I remade all the panels, what a major pain in the ass. Had to cut some in half and used Simpson StrongTie Straps and zip screws and Gorilla Spray Glue to put each hanger together. What a drag. If only I did more research and made my traps 24" from the start. I also angeled them towards the speakers. 19 traps total. 3 16" traps corner in closet and one in the center, then 16 24" hangers angled towards speakers.

My speakers from the original baseline measurement got adjusted, so i made a NEW baseline measurement with the room empty. Then i added insulation on the closet wall, sides and ceiling and i made each hanger 24" (plus 3" of insulation. )

Looks like my low end decay times are well on their way, but am i missing anything? is 50hz at 300ishms as low as it gets in a room like this? Is my SPL dip at 92hz and 120 hz a SBIR issue? i'm still learning how to analyze REW, would love to hear more. Still gotta trap the First reflection points and The space directly behind the speakers.

I'm planning to hang my 4" traps to create an RFZ, and build a new 6"hard backed ceiling cloud angled to divert reflections.



What an awesome project, would appreciate any more analysis and tips on my room.


Best,
vic

Almost forgot Here’s some pics of the closet lined and then the hangers hung, latest tests include front wall corner super chunks.

RT60 is looking good, but was hoping 50hz would look a little better, like below 300ms

Is that possible? Is my rear wall bass trap not as effective as it should be?

Nice work, well done for persisting. I've had a look at the REW data and the "closet final" makes a huge difference, all the way down to 30Hz and below. It seems to have flattened and moved the 32Hz length mode peak down to about 30Hz. I recall reading that this is because the absorption effectively makes the room a bit longer. Nice to see the effect in action.

The chunks do a good job too around the lower mids, but don't extend much further down than that.

There are some huge spikes in the RT60, any idea what is going on there? Is that just because you haven't finished the room treatment and there are still some resonances, first reflections or what have you kicking about?

50Hz corresponds roughly to the room width, so perhaps there is not enough treatment there?

92Hz is a multiple of the room length mode, so you might want to check that. Are there any significant panels addressing this?

I believe 120Hz null is a common symptom of SBIR. It is also a multiple of the room length mode!

Do you have any photos of the current state of treatment?

Cheers,
Jennifer

Hey again Jennifer, thanks for following along and checking out my .mdat

So with those measurements so far only the closet and front corners are treated. The rest of the room is bare, which is what I assume is why the RT60 has spikes in the upper range, hoping to get my 4" thick traps hung up at first reflection side walls tomorrow.

I still have to build the ceiling cloud so that might be a little later.

50Hz corresponds roughly to the room width, so perhaps there is not enough treatment there?

Any idea what kind of treatment could help mitigate these?
I could make two more superchunks at the rear corners in front of the closet, but as you noticed they didn't seem to affect the low end in the RT 60 by much. Perhaps a tuned trap of sorts could do the trick, Where to place such a trap and what kind should i look into, is this even necessary?

92Hz is a multiple of the room length mode, so you might want to check that. Are there any significant panels addressing this?

I believe 120Hz null is a common symptom of SBIR. It is also a multiple of the room length mode!

Same question, I'm not exactly sure how to deal with a room mode the length of the room, I was hoping the closet bass trap would address these haha. Is more broadband panels around the room in addition to the first reflection points a good solution?

I still have 8 smaller (23" face & 17" deep at the sides) superchunks I can install in the various ceiling corners. I could experiment and see how they perform, but it is kind of a pain to hang them without knowing how they will respond. I guess i could lay them on the floor and see how the room reacts to get a better idea. I'll do that.

Was definitely hoping to come up with a plan to deal with my specific issues instead of just stabbing in the dark like i normally do, so any advice or information/articles would be awesome. Perhaps once I place the first reflection panels and test I'll have a better idea of what i need.

Is there any way to determine what a good RT60 looks like for a room this size? Like what specific decay timing should i be trying to achieve based on my rooms volume? is there a formula or a general rule i can apply? I know a well balanced/even decay across the spectrum is generally more important but just trying to get an idea of what my goals should be.

All the best and thank you for taking the time.

So I went ahead and arranged the remaining traps I had laying around and roughly placed them in the room just to get another idea. Here's the photos of the room and the new .mdat file.






I was actually quite impressed at how much smoother the T30 measurement in RT60 became above about 300hz.

Ceiling cloud will hopefully make another big difference but I'm not sure exactly sure if that will address nulls around 90hz to 120hz or the decay times from 50hz to 100hz.

And for the ceiling cloud, i was planning to make a 6inch thick roxul safe and sound 4 ft by 6 ft trap, however concerning the RT60 from 50-100hz, perhaps i should go even thicker? I could possibly do a 9" thick trap? Is fluffy fiberglass better at that thickness vs the safe n' sound from Rockwool?

And for anyone curious but not curious enough to download the file, would love to hear your thoughts.

victorr_sun wrote:Source of the post The rest of the room is bare, which is what I assume is why the RT60 has spikes in the upper range, hoping to get my 4" thick traps hung up at first reflection side walls tomorrow.
I still have to build the ceiling cloud so that might be a little later.

I just looked at the new measurements now you've done that. It has made a huge difference. The floor wedges have a big effect from low mids up, and some effect in the very low range. Combined with the side panels they've really cleaned up the room acoustics. Lovely to see.

A ceiling cloud is crucial, and should be done before other considerations such as tuned traps and smaller incremental improvements. I reckon it will give further improvements, hopefully around that 80 - 150Hz portion. I suspect fluffy fibreglass at 9" depth is not appropriate; I think you have to be getting close to 24" for that. Other people have mentioned angled hard back clouds, is that something you've considered? I've not tried it myself, but my room has an angled ceiling where the cloud would be, and it does seem to give benefit.

Have a look at this porous absorber calculator, it models the response of various options; http://www.acousticmodelling.com/porous.php

To aid in this quest I'd recommend looking at the impulse charts. Sometimes they are easier to interpret if you switch from dBFS to %. The ideal is to have no peaks in the first 25ms or so above -20 dBFS. You have a peak around 3.80ms in the left and right. This represents the additional delay of a reflected signal from the direct signal. From this time you can calculate the additional distance the reflected sound has travelled. Use Stuart's string trick to find the surface causing it, and treat accordingly.

Stuart's string trick is described in this post viewtopic.php?p=1373#p1373

Only do impulse assessments on the single speaker measurements by the way!

50Hz corresponds roughly to the room width, so perhaps there is not enough treatment there?

Any idea what kind of treatment could help mitigate these?
I could make two more superchunks at the rear corners in front of the closet, but as you noticed they didn't seem to affect the low end in the RT 60 by much. Perhaps a tuned trap of sorts could do the trick, Where to place such a trap and what kind should i look into, is this even necessary?

I'm not sure superchunks in front of the rear closet would make much of a difference as you say. You could always measure the room with & without them and make a judgement. By the time you have the ceiling cloud, ceiling chunks and side wall treatment it may well get good enough anyway.

92Hz is a multiple of the room length mode, so you might want to check that. Are there any significant panels addressing this?

I believe 120Hz null is a common symptom of SBIR. It is also a multiple of the room length mode!

Same question, I'm not exactly sure how to deal with a room mode the length of the room, I was hoping the closet bass trap would address these haha. Is more broadband panels around the room in addition to the first reflection points a good solution?

I made a typo there, doh! Of course the closet trap deals with the length mode, and very effectively Taking a few measurements with the mic slightly forward and behind the current position might give some insight and possible improvements. Stuart talks about the walking mic tests for this. It's laborious but might help identify what is from room modes & SBIR.

Is there any way to determine what a good RT60 looks like for a room this size? Like what specific decay timing should i be trying to achieve based on my rooms volume? is there a formula or a general rule i can apply? I know a well balanced/even decay across the spectrum is generally more important but just trying to get an idea of what my goals should be.

There is. Have a look at page 6 of EBU Tech 3276-1998 "Listening conditions for the assessment of sound programme material: monophonic and two–channel stereophonic". It gives you a formula to calculate this based on room volume. From a quick look, I'd say you are already very close. There is an increasing tolerance for reverberation times towards the lower frequencies.

https://tech.ebu.ch/docs/tech/tech3276.pdf

Cheers!
Jennifer

Wow been exactly a year since the last reply from Jennifer, Thank you by the way. it was extremely helpful and I hope you're doing well if you see this. Got so busy with work, but been back at it grinding to get this room dialed finally. I'm pretty close i think, at least to the furthest extent of my knowledge/abilities. There is still a big modal issue as we discussed before, but moving the mic forward a bit seemed to help lessen the depth of the first big null.

I've attached the new files and some photos, if anything is glaring or obvious I'm always open to advice, ideas and learning. Still have to wrap the closet with a proper fabric so don't mind the bed sheet in the mean time

Photos


For the cloud I originally thought go big or go home, since i'm sure I'll be moving to a bigger room eventually, although i didn't consider that with a standard 8 foot ceiling a 4 foot wide cloud would not allow me to get the proper angle.

Thankfully i tested it before wrapping in fabric, however i had to disassemble it, rip and frame my 4' x 6' cloud down to two separate 2' x 6' clouds. they are about 7" thick with Rockwool Safe n Sound, and a 1 and 3/8" thick hard backing made of 5/8" MDF and 3/4" plywood glued together, with 6 inches thick of Insulation. They still seem a bit too large for my ceiling height but for now but it seems to help on the early Impulse chart.


Positioning the cloud was a pain, still not sure if its perfect but it seems to be helping now after some experimenting with position. I used a unistrut channel system to mount them to the ceiling, unfortunately I lose a couple inches in max height clearance from the hardware but much easier to adjust the position vs mounting directly to ceiling joists as mine run in the wrong direction. Perhaps i can tie the hardware up tighter to gain an inch or two in height.

I made some wooden frames and wrapped them to cover my big front corner bass traps. Also had to disassemble two of my little portable super chunks and cut them by a few inches to stack them vertically in the rear then reassemble them.
What a pain removing hundreds of staples. I also hung my old cloud in the rear of the room near the couch, to try and help any ceiling reflections if I'm recording a vocal or acoustic guitar back there.

The wall area in the middle of the room where there is no trapping still has an annoying flutter echo. I have two more frames for broadband traps almost ready to add to the sidewalls of the room, but I guess i may have to cover the entire wall area to fix that, hopefully it doesn't come out too dead.

Incidentally, I've been more conscious of dust and have began wrapping my clouds and bass traps in .3 mil painters plastic underneath the fabric to help with allergies and what not. I've noticed the dust escapes whenever the traps get disturbed/moved so trying to avoid that especially on the ceiling mounted traps. I think i read somewhere that Stuart or John would wrap their ceiling traps in plastic to help with dust and as a side benefit overall liveliness of the room.

If anyone has any insight on how or if its possible to treat my room mode peaks/nulls I'm all ears, would a tuned trap of sorts be a good idea?

I was already thinking of pushing my current sidewall first reflection traps back towards the couch to cover more wall in the rear and building this trap designed by John Sayers. One because i think some wood and angled dimension would help break up the monotony of mostly fabric/ parallel wall and also in the hopes that it may sound better at the listening position.

Since his passing it seems the original John Sayers site was not maintained as it was originally intended to be. Fortunately with the help of the wayback machine internet archive i was able to dig up the pdf for his wall units.

Any experts have an opinion on whether this trap seems like a feasible idea in my room? Not sure what frequency range i should aim for, and I'm uncertain on how effective they are as a broadband tuned trap, although that's what John specifies in his design. I will definitely keep experimenting and hopefully get some feedback from Jennifer or anyone else reading.

Best,
Vic