Show me your Panels!

[phillihp23]

 

[phillihp23]

 

[phillihp23]

I didn’t make them, just rewrapped them in black.

 

[Travis Ballstadt]

My panels are more "non-reflective decor", but I put some leftover Linacoustic inside, just because.

 

[Anand Raman]

One of the 3 diffuser panels (1 on each side wall near listening position and 1 on the back wall):

From 35Hz on up, you will notice an even and rapid drop of at least 40dB in less than 400msec.

 

[NBPK402]

Looks great and measure great too! Did you make the box diffusers yourself? Are the metal pieces next to your slotted wood ones diffusers too?

 

[NBPK402]

In my last HT... I covered the whole front wall with 3" thick Roxul, and stuffed the front stage with insulation (around a DTS10 sub). I made all of the walls with fabric covered frames, and had the first reflection points filled with 4" of Roxul (walls and ceiling). For the rear I stuffed the rear stage with insulation (around the 2nd DTS10 sub), triangles floor to ceiling for corner bass traps, and the whole rear wall was 9" of Roxul for a bass trap. Room sounded great, but was right on the line of too much absorption. The room was so quiet we could hear a truck drive by in the Pitch Petfect movie in the background of one of the scenes. We thought at first it was a truck driving by the house, but it was 100% repeatable. In my new house it is so live I cannot retrieve that level of information yet. Room, treatment is def #1 best improvement for any room IMO.

 

[JStewart]

@Anand Raman that’s one really nice looking room and bass response!!
By chance are those speakers constant directivity and toed for time-intensity trading?

 

[Anand Raman]

J.Stewart and NBPK402, thank you for the compliments.

Here is a description of my room (of which only 1/2 is shown in the above pics):

Room construction:

The room construction involves 2 external solid core doors with rubber seals, and integrated door sweeps. Between the 1st door and 2nd door, there are full range GIK 244's for additional isolation. Next, there is a double drywall w/Green Glue and over 200 RSIC-1 clips and multiple furring hat channels. 2 rows of studs were implemented on the front, rear, left and right walls along with additional isolation techniques for the ceiling. There is a 1 inch gap between the rows of studs so that the adjoining room does not engage in sympathetic vibration when the walls of the listening room vibrate! QuietGround Rubber underlayment for the floor. Separate equipment room with very similar construction. All outlets, whether power or speaker have their own MDF enclosures. Ceiling lights have their own soffit. In addition, extensive attention was placed on HVAC design, use of mufflers, etc...

Acoustic treatments:
The room is carpeted. GIK Acoustics, Listen-Audio, Arqen & Custom DIY acoustic panels.

Front wall and immediate side walls
4 GIK 242 panels on the front wall with 5 Stepfractal diffusers in a stepped aperiodic array. Pair of GIK Tritraps in each front corner; 2 GIK Soffit traps on floor/side wall junction to treat SBIR. 4 GIK 4A Alpha Woods in blonde veneer on each side wall in front of the sidewall 1st reflection treatments. Each sidewall 1st reflection point has 2 Aperture Diffraction Grating wide bandwidth hybrid diffusers;
Ceiling
10 GIK Grid fusors and 1 GIK 242 panel on the ceiling;
Rear walls and immediate side walls
5 Stepfractal diffusers in an aperiodic array on each of the rear side walls; 2 GIK QRD's on left upper rear corner, with 3 GIK Monster Trap FRT w/Limiter; 1 GIK QRD each on the bathroom door and front door covering the upper right rear corner, and 2 GIK 244's FRT w/Limiter on lower right rear corner; 4 Stepfractal diffusers in an aperiodic array on the mid to high rear wall combined with a 4 inch OC703 fiberglass w/FSK with air gap; 1 GIK Monster Trap on mid rear wall and 1 GIK Monster Trap FRT w/Limiter on low rear wall/floor junction;
Ceiling bass trap
Soffit on *entire* ceiling perimeter doubles as an absorber by having a combination of OC703/FSK w/ fluffed fiberglass similar to GIK Soffit trap.

If you want to see individual measurements of the diffusers, wide bandwidth and narrow bandwidth absorbers, they are all available at GIK's, Arqen's and Listen-Audio's websites. Some are predictions using AFMG Reflex software as it is very difficult to measure diffusers accurately. The absorbers on the other hand are measured at Riverbank Acoustical Laboratories.

Speaker and subwoofer setup:

Speakers are 10 feet apart and toed in such that the central seat is 20 degrees off axis to the main speakers. The speakers are of constant directivity design (GedLee NA12), and are about 4-5 feet from the front wall/corners. Listening position is roughly 10-12 feet back. Back wall is at least 10 feet behind me. One Tsunami I sub is on the left side wall near midpoint of room. The other is at midpoint on the right side of the room. The Tsunami II is at the rear right side of the room. The Funk 21.0LX sub is on the rear left side wall/corner. Entire low end response from 20-300Hz was optimized using a calibrated MiniDSP-UMIK-1, and software. It is better than +/- 3 dB *without* smoothing from 17-300Hz and +/- 2dB with 1/12th octave smoothing. Surprisingly, DSP is only used on the Funk 21.0LX ULF sub to extend ultra low bass.

I used to use the room for dual purpose HT and 2ch. Unfortunately, I hardly use the HT portion of the setup, as such it is taken down and I primarily use the room for a 2ch system with an asymmetrically distributed multisub system. It goes without mention that I am a disciple of Floyd Toole, Todd Welti, Earl Geddes, and Duke LeJeune.

Minidsp primer on multisubs (with discussion regarding Harman's symmetrically distributed multisub setup vs. Geddes' asymmetrical recommendations)
Serious Audio Blog primer on Geddes' multisub papers
Hifizine Bass Integration Guides
2ch “In Room” Acoustical Measurement Standards

The Tsunami 1 sub design is my own and is a 1.5 cubic foot sealed box with a BMS 15n850V2 driver. I have 2 of these subs. They are powered by a Neurochrome Modulus series stereo amplifier.
The Tsunami 2 sub is also my own, and is a dual opposed sealed design of approximately 4 cubic feet using (2) B&C 15BG100's. It is powered by an ICEEDGE 1200AS amplifier (1200w/4 ohms).
The Funk Audio 21.0LX is an exceptional subwoofer design , and uses a Funk 21 inch underhung woofer with incredibly low inductance in a 5 cubic foot sealed enclosure, a 2.4KW plate amp using a Pascal Class D design with a pretty versatile DSP module.

I use a heavily modified Behringer DCX2496 (AMB Kappa DCX modification) as the main DSP processor to set all 4 subs. Surprisingly due to proper placement of the subs, xo frequencies, phase, and crossover slopes, I have had to implement very little DSP (i.e. EQ). This is terribly important to appreciate and understand as it proves to me that an asymmetric distribution of low frequency modules really does work in minimizing spatial differences of bass perception in small rooms.

Discussion/Impressions:

The use of low inductance ultra low distortion subwoofer drivers of very high efficiency (93-96dB) is the key to having a very fast midbass that is at least as good as open baffle subwoofer designs (like GR Research/Rythmik) but with distinct advantages in attack, ultimate SPL capability, and deep bass extension. Motor design is paramount and absolutely everything. Building boxes is super easy and requires little knowledge for the diy’er. I auditioned several prospects and thankfully several pro audio companies design some of the finest woofers that are 15 inches and greater (i.e. B&C, BMS, LaVoce, Ciare, Funk, Faital Pro, etc…). Most "hifi" woofers are either designed for great midbass or great bass (extension) but usually not both. Several are just too small with tiny piston areas and swept volumes. Compartmentalizing the advantageous motor designs for midbass and then 1 or 2 other “conventional” woofers designed for low bass extension is an excellent compromise.

That being said, my 'bass system' is somewhat the exception to the rule (i.e. I didn't want to compromise ). The Funk Audio 21 inch driver has both exceptional midbass and low bass extension to boot. You would expect it to be a 'big thumper' but it's not. In fact, it augments the other 3 monopole subs. And yes, the other three have gobsmacking midbass which are essential for 2 ch music but with frequency extension to only about 40Hz. Put them all together and the result is sublime.

The placement of subs cannot be done without didactic in room measurements such as those afforded by John Mulcahy's excellent REW program. I am greatly indebted to him and his free software design. By using an asymmetrical multisub setup as well as room treatments (while being able to harness the technological advancements of stringent motor design that is typically reserved for the finest systems and large venue installations) one should be able to easily address modal issues, SBIR, and in particular, the "modal region."

I firmly believe that a properly designed low frequency setup is at least 30% of the playback performance as it has distinct effects in not only bass perception, realism but sound staging and imaging as well. This may not be obvious to a lot of folks. It's not about 'thumping' bass, it's about finely delineated bass detail that can be appreciated even at the highest SPL levels. Properly done, it affords a 'realism' to any 2ch playback system.

Best,
Anand.

 

[Anand Raman]

Looks great and measure great too! Did you make the box diffusers yourself? Are the metal pieces next to your slotted wood ones diffusers too?

The diffusors next to the slotted wood ones (GIK Alpha 4A) are from Listen Audio and yes they are diffusors, a modified MLS type to be accurate. They appear to be 'metal' because they are in a carbon fiber veneer. They are actually made out of MDF.

Thanks,
Anand.

 

[PaulSmt]

I don't have any photos of these panels, but I will make them soon and send them here.