Need help from you acoustical experts

Wow, thanks for all the responses.

A couple things: The GIK Impression panels are marketed as absorption & diffusion which the wooden decorative plates are supposed to be providing the diffusion.

baylinor There ARE bass traps in the corners behind the speakers.

I’ve had these speakers for a long time (and have been considering a change). They have been in 3 rooms and every time I’ve pulled them away from the back wall they loose bass, but I’ll give it another try in this room.

ronboco I did build this room myself. I consulted the people at GIK and went with their advice, and they wanted me to buy more so yeah, they are trying to sell treatments. I’ll look at hdacoustics.

I’m not an acoustical expert, however I designed presentation rooms for Corporate Clients for 46 years, often with acoustical engineer consultants I hired. Larger spaces of course, but the issues are similar.

75 yrs old, I have messed about with several residential systems, particularly the spaces for me, my friends and client’s homes.

Everything Adds Up.

I suggest:

1. Document the sound reaching the listening position

a. Inexpensive SPL, with Tripod Screw, like this one

https://www.amazon.com/Pressure-Measure-Material-Digital-Decibel/dp/B0CBMQ8TKG/ref=sr_1_14?crid=3FLRYI6K0TK0U&keywords=sound+pressure+level+meter&qid=1693575743&sprefix=sound+pressure%2Caps%2C105&sr=8-14

b. Test CD (not LP), with individual frequencies, I use this, 29 separate frequency bands (not sweeps or white noise)

https://www.discogs.com/release/7290000-Various-Amazing-Bytes

expensive, I could find you an inexpensive copy.

2. Meter, Tripod, Seated Ear Height, Copy of Frequency Chart

select individual frequencies (no need to do every one, I do every other one.. write what you are getting

Now you have measured facts, go from there.

3. Ceiling Tile Types, you want

a. STC (Sound Transmission Coefficient) Low keeps the reflected sound IN your space. You want high sound transmission.

b. SAC (Sound Absorbent Coefficient), the tile texture/material absorbs, and allows sound to pass thru, not reflected in your space. I often would put special 3" thick tiles, sometimes rolled absorbent insulation above the tiles (over stock broker’s desks), they also make foam sheets, unseen but they do their job.

BTW, for ceiling return air vents, I had them make a one foot high collar above the grille, lined all 4 sides with insulation, to keep sound from reflecting diagonally off the slab above then thru the sheetrock wall above the ceiling into adjacent offices.

c. My ceilings are Homasote, with wood strips concealing the joints. Painted, but slight texture and ’soft’ characteristic

https://www.homasote.com/

shows best photo 3 here

https://www.audiogon.com/systems/9511

the walls are textured wood panels like raked plaster, above system photos, photo #2, left side

4. Rearward Slant: Front spacer/lifter to get Tweeter aimed up, directly at seated ears (tweeters have the narrowest ’equal’ dispertion).

This importantly alters the angle of reflection off the floor and ceiling, combined with toe-in angling/altering side wall reflections (combining/affecting rear wall reflections).

5. Toe-In

a. single centered listening position: aim each speaker directly at the centered position.

b. Two listeners: assuming a small drink table between two off-center chairs

aim left speaker at right chair, right speaker at left chair. each chair gets more direct sound from far speaker, combined with more sound from the speaker they are closest to. Gives acceptable imaging to both.

c. assumes relatively easy ability to pivot speakers outside front corner ’in’.

My heavy speakers, I have 3 wheels (2 front, 1 rear). 3 because more weight per wheel than 4, and 3 always find solid footing without needing leveling.

Lighter speakers, some kind of ’slip’ material, felt/plastic corners, ....

6. Repeat Sound Pressure Meter/CD test, now see what seated listening position is getting.

7. Level Controls, a pet peeve of mine.

a. Speakers should have level controls to adjust the mid to the woofer, and the highs to the mids. All the old ones (that speaker companies made their reputations with) had them, as the space they would be used is was unknown.

b. unknown space is still an issue. Today, use good tone controls, separate equalizer, and again measure with SPL while adjusting/correcting.

8. YOUR Preferences, YOUR Hearing, measured is a start, next, what highs do your old ears hear, what do you like, what do your old ears perceive.

I am 75, after I use meter to get the best, then I use music I am familiar to push the highs more, but not too high, using Eurythmics Sweet Dreams; Blue Nile, Walk ... Rooftops; Andreas Vollenweider, White Winds; No More Tears Duet Barbra Streisand/Donna Summer; Jeff Wayne’s War of the World: other music with highs, and highs sometimes left, sometimes right to maintain balance while pushing each L&R up a bit.

 

 

 

@traudio excellent advice from @newbee, @erik_squires and others.
You have to give the speaker positioning suggestions a try. Move them out into the room more, i.e. the suggested 4ft from the front wall (behind speakers), listen. Then spread them further apart by about 1”, toe them in so you get a solid center image. Evaluate. Make small adjustments from that point on with distance to walls, between speakers (measured at center of drivers) and your chair. 
It’s a tedious and time consuming process but is 100% worth it. You will either get it to sound the way you like or you will realize it’s time for a change.

Reading @elliottbnewcombjr's post and looking at his photos reminded me of this rather old site, Mother of Tonehttp://www.mother-of-tone.com/index.htm. It deals with vibrations and materials that carry them.

They sell, as well as instruct on construction of, birch wooden panels treated with organic lacquers that have favorable vibrational qualities pleasing to the ear. There's also a section of room acoustics that might be worth a read that goes contrary to some of what's been posted here. 

Here's a shot of the owner of Audiovector's room and the treatment of the front wall:

Posting this had my muse whisper in my ear that something as simple as textured wallpaper can do wonders for reducing echo and reflection, which may be all one needs for their room. Just more food for thought.