My dedicated audio room build - QuadDiffusor's Big Dig

[QuadDiffuser]

Further simplifying, with recommendations expressed in a chart. Accordingly, instead of running my Ground conductor straight through in parallel as I have planned, instead I'll try to spiral it loosely around the tightly twisted Live + Neutral pair.

Final Recommendation:

The best configuration, as per the patent, is twisting the live and neutral (or phase) conductors tightly while keeping the ground wire untwisted or twisted at a much lower rate, maintaining a constant separation from the current-carrying wires.

 

[QuadDiffuser]

Speaker Positioning (relative to the room dimensions)

Luckily, there's ample space in my listening room for flexibility and latitude in speaker placement. Of course, these positions are not dogmatically set in stone and will be subject to experimentation and tweaks during the auditioning process to determine the optimal positions.

1) The rearward-facing subwoofer will be placed at a deep null position, corresponding to 25% of the room length.
[9,795mm / 4 = 2,449mm] This should help "couple" the subwoofer's output more effectively into the room's primary resonance mode.

2) The forward-facing tweeters and midrange driver will be placed at 33.3% of the room length, following the "Rule of Thirds".
[9,795mm / 3 = 3,275mm] The 100mm offset seen in the diagram is to compensate for the sloping baffle of the Ultra 9s (see photo).

 

[QuadDiffuser]

Listening "triangle"

The separation of 3.0 meters (9.85ft) between the speakers worked well in my smaller apartment listening room. For this larger listening room, it's going to be just a touch wider, at 3.1m (10.17ft), but remaining relatively closer together to ensure solid lower frequency coupling between the two speakers.

A 60-60-60 equilateral triangle configuration would place the listening position at exactly 3.1m, delivering a near-field listening experience. I'll try adding 10% more distance, pulling the listening seat away slightly, perhaps into the beginning stages of a mid-field perspective. The extensive room treatment with QRDs (on the front wall, side walls, and ceilings) will ensure that the direct sound from the loudspeakers will remain distinct and vivid even in the presence of an abundance of indirect sound (thanks to the decorrelation and randomization of the latter).

Though not shown in this diagram, the speakers will likely be toed-in slightly, between 10-20 degrees. While Damon Von Schweikert's tuning wizardry will be invaluable when he personally visits me one day, ZOOM calls likely suffice, in the meantime.

 

[QuadDiffuser]

Sidewall's 1st reflection point - surface of the QRDs

Here's what happens after sound from the loudspeakers strike the SURFACE of the P17 QRDs.

It's important to understand both the time delay (calculated via distance traveled), and the path angle (as it will affect the perception of soundstage ambiance).

Time taken for the direct sound to arrive: 343m/sec (div) 3.410m = 1/100.59 = 9.94msec
Time taken for the 1st reflection to arrive: 343m/sec (div) [1.653m + 3.492m] = 15.0msec (matching the second graph below)
Time delay = 5.06msec

 

[QuadDiffuser]

Sidewall's 1st reflection point - inside depth of the QRDs

Here's what happens after sound from the loudspeakers strike the BACK (inside) of the P17 QRDs, factoring in their depth of 406mm (16 inches).

It's important to understand both the time delay (calculated via distance traveled), and the path angle (as it will affect the perception of soundstage ambiance).

Time taken for the direct sound to arrive: 343m/sec (div) 3.410m = 1/100.59 = 9.94msec
Time taken for the 1st reflection to arrive: 343m/sec (div) [2.049m + 3.795m] = 17.04msec (matching the second graph below)
Time delay = 7.1msec

 

[QuadDiffuser]

Note that the two red lines which converge to the listening position (in the first graph posted above) creates a lateral angle of around 120 degrees. This angle is very important in terms of creating a soundstage in which the perceived soundstage "envelopment" is optimal.

Back in post #30, I mentioned this phenomena, citing a page from Floyd O'Toole's book "Sound Reproduction: The Acoustics and Psychoacoustics of Loudspeakers and Rooms".

My dedicated audio room build - QuadDiffusor's Big Dig

There is of course another room acoustical technology that provides a third approach to dealing with low frequencies. Developed for and in use by well known film/recording/mixing studios (links to examples below), it is based on very high numbers per sf of non-parallel surfaces (DHDI ZR...

www.whatsbestforum.com

Essentially, I will be synthetically creating setup "(b)" (see the green highlight) in the chart below. The near-equilateral triangle placement (60-degree spread) of the L/R speakers will provide the primary +/- 30* soundfield. The slightly attenuated and diffused sidewall reflections from the P17 QRDs will provide the 120-degree spread.

 

[pjwd]

Sidewall's 1st reflection point - inside depth of the QRDs

Here's what happens after sound from the loudspeakers strike the BACK (inside) of the P17 QRDs, factoring in their depth of 406mm (16 inches).

It's important to understand both the time delay (calculated via distance traveled), and the path angle (as it will affect the perception of soundstage ambiance).

Time taken for the direct sound to arrive: 343m/sec (div) 3.410m = 1/100.59 = 9.94msec
Time taken for the 1st reflection to arrive: 343m/sec (div) [2.049m + 3.795m] = 17.04msec (matching the second graph below)
Time delay = 7.1msec

View attachment 147797View attachment 147798

QD .. assuming you are getting somekind of hemispherical dispertion from the qrd aren't you going to get a small component of reflection from each diffuser ( much more complex than sketch .. varying angle of incidence, lobing etc.) Plus a reduced db .. I am not saying that's a bad thing as it most likely will not impact on your perception of direct sound .
Are there published dipertion patterns for type 17 qrd
Phil

 

[MarkusBarkus]

...I have never fully resolved the reflection patterns for the QD on sidewalls in my mind. They seem to work well and I like them in my room (back wall), but it seemed to me that the measurements and the concept was predicated on a "direct hit" into the diffusor, utilizing the various different back-wall depths to create the desired effect.

If waves enter the various chambers at an angle, it seems to me a more complicated reflection pattern emerges. This is just a thought puzzle for me, as I cannot measure the condition here, only hear the end results, which I enjoy. Thanks for the info QD. Looks terrific.

 

[QuadDiffuser]

The purpose is to understand the principle of 1st reflections, as stated by the law of reflection, ie. that the angle of reflection is always equal to the angle of incidence. In other words, the most direct reflection with the shortest path length between the speaker and the listening position will have the highest amplitude and arrive the soonest, hence will be the most audible and significant influence.

Markus and Phil - I've posted the charts below before, but I'll do so again, as they will (again) explain what happens to different sound frequencies when they strike the P17 QRDs at 45 degrees. Sound from the loudspeaker does NOT have to hit straight-on, at zero degrees, with a "direct frontal hit" for the QRDs to do their job. "Complicated" diffusion patterns are just fine, as long as they have the following four characteristics.

Since the Von Schweikert Ultra 9 has a very broad and uniform directivity index, acoustic energy launched into the side hemisphere will strike the P17 QRDs and diffuse back into my listening room, creating a nice ambiance or "air" to the presentation, through the following "contributions":

1) delayed by 5 to 7 milliseconds (between 5 and 30ms is optimal to utilize the positives of the Hass Effect - will explain later).
2) attenuated in amplitude, uniformly across the broad frequency spectrum without significant hot or cold spots (unlike foam absorbers)
3) scrambled in the time domain across the broad frequency spectrum, due to the different well depths in the QRDs
4) primarily originating from 60-degrees left of center, and right of center, for a spread of 120 degrees

Scattering, diffusing, and (slightly) delaying direct sounds from the loudspeakers are WONDERFUL ingredients to add to the direct sound!!! Yes, TRIPLE exclamation marks.

 

[pjwd]

The purpose is to understand the principle of 1st reflections, as stated by the law of reflection, ie. that the angle of reflection is always equal to the angle of incidence. In other words, the most direct reflection with the shortest path length between the speaker and the listening position will have the highest amplitude and arrive the soonest, hence will be the most audible and significant influence.

Markus and Phil - I've posted the charts below before, but I'll do so again, as they will (again) explain what happens to different sound frequencies when they strike the P17 QRDs at 45 degrees. Sound from the loudspeaker does NOT have to hit straight-on, at zero degrees, with a "direct frontal hit" for the QRDs to do their job. "Complicated" diffusion patterns are just fine, as long as they have the following four characteristics.

Since the Von Schweikert Ultra 9 has a very broad and uniform directivity index, acoustic energy launched into the side hemisphere will strike the P17 QRDs and diffuse back into my listening room, creating a nice ambiance or "air" to the presentation, through the following "contributions":

1) delayed by 5 to 7 milliseconds (between 5 and 30ms is optimal to utilize the positives of the Hass Effect - will explain later).
2) attenuated in amplitude, uniformly across the broad frequency spectrum without significant hot or cold spots (unlike foam absorbers)
3) scrambled in the time domain across the broad frequency spectrum, due to the different well depths in the QRDs
4) primarily originating from 60-degrees left of center, and right of center, for a spread of 120 degrees

Scattering, diffusing, and (slightly) delaying direct sounds from the loudspeakers are WONDERFUL ingredients to add to the direct sound!!! Yes, TRIPLE exclamation marks.

View attachment 147824
View attachment 147826

Thanks for that.. we are on the same page .. that is what I was illustrating .. you will get reflected information from a wider area of the wall at a much reduced volume... I would expect the reflections from the full depth of the qrd will be quite delayed ( within the range of effectivenes)
It's interesting that most published dispertion patterns are from a perpendicular source whereas we are always listening at an angle .
As you know we have differing views on correlated vs non correlated reflections but I am sure this will sound amazing

 

[QuadDiffuser]

This Seismion Reactio2 (active vibration reduction platform) has significantly elevated my apartment system’s bass performance and overall articulation - highly recommended! Will be buying a few more for my future basement system.

Audiophile – Seismion

seismion.com

 

[QuadDiffuser]

The PowerLab Century sub-MCB with built-in noise reduction circuitry (tourmaline powder?) will be replacing my smaller plain-vanilla PowerLab Galaxy 6. Mine will come with six 32A breakers and four 20A breakers, expandable to six more for a total of 16 breakers.

Power Lab Century Fuse Box

The best audiophile grade fuse box currently available in the market that money can buy.

powerlabb.com

 

[Kingrex]

Fancy power panel. Is it surface mount and designed to be taken with you when you move?

 

[QuadDiffuser]

Yes, it's portable, at just under 25kg. But I doubt that I'll ever be moving (again), as the new house (and the basement audio room) will likely be my "forever" home.

I'll be posting and sharing all of the gory details of the AC power line design, routing schematics, etc. I'm thinking of skipping AC duplex outlets and "audiophile" AC cables altogether, hard wiring the extremely high quality in-wall AC cables from the breakers DIRECTLY into the input plugs (then into the component's IEC inlet) by using these babies:

FI-50 NCF(R) | FURUTECH

FI-50 NCF---15A 125V /10A 250V AC

www.furutech.com

Will need to figure out whether 6mm2 and 10mm2 copper conductors can be crimped into Furutech's mini spades, and then connected to the innards of the plug.

 

[pjwd]

Yes, it's portable, at just under 25kg. But I doubt that I'll ever be moving (again), as the new house (and the basement audio room) will likely be my "forever" home.

I'll be posting and sharing all of the gory details of the AC power line design, routing schematics, etc. I'm thinking of skipping AC duplex outlets and "audiophile" AC cables altogether, wiring the extremely high quality in-wall AC cables from the breakers DIRECTLY into my components by using these babies:

FI-50 NCF(R) | FURUTECH

FI-50 NCF---15A 125V /10A 250V AC

www.furutech.com

Will need to figure out whether 6mm2 and 10mm2 copper conductors can be crimped into Furutech's mini spades, and then connected to the innards of the plug.

View attachment 148331

The bocchino plugs will easily accommodate those guages .. I use them for similar purpose and built a direct wired power distributer .. save a lot of plugs and sockets

 

[Kingrex]

I love that idea. I have fiddled with it and it is by far the most superior way to connect. As direct as possible with as few breaks and contact points as possible. A cable, hard wired to a panel with good wire, then terminated with a quality IEC connector to gear would beat any $20,000 power cable having to pass through a duplex. Even better, you could slug the fuse in the equipment and use an appropriate CB. For example, a 3.2 amp or 5 amp CB to match the fuse you removed. Can you say, Swiss Digital Fuse.

I know little about code details in europe.

In the US and Canada, they would say your feeding equipment that is not permanently attached. Its not a HW tank, Oven or similar. Code says non permanently attached equipment shall be fed with a cord that plugs into a duplex. They wont let you hard wire.

You could hard wire to the panel with hard usage SO cord. That would have to terminate into a duplex outlet. Then a plug in cord from gear to duplex. That would sound awful.

You could nipple a box of quality duplex to the panel enclosure and load it with premium wire and premium outlets. That would perform at a very high level.

Personally, I would travel the path you noted. It will sound amazing.

 

[QuadDiffuser]

The bocchino plugs will easily accommodate those guages .. I use them for similar purpose and built a direct wired power distributer .. save a lot of plugs and sockets View attachment 148348

Thanks, Phil !
Extremely short on photos and diagrams, but I'll try starting with the following website/page:

baluga

 

[pjwd]

Thanks, Phil !
Extremely short on photos and diagrams, but I'll try starting with the following website/page:

baluga

Well done finding that !
I will PM you

 

[Kingrex]

I have terminated and installed Bocchino. They work well. There are other options as well. Bocchino is not the end all. Remember to Caig Deoxit G100 all parts well as the surface is coated with Silver and will tarnish fast.

You can also use Furutech, Watgate and others. I personally, just me, look for as pure a copper as I can get. No plate metal. I try and avoid colorations from plate metals.

Sometimes the Bocchino are an issue with fit. The bodies are so large they cram the insertion location. Be aware. Try a test fit before you bother to terminate.

 

[pjwd]

I have terminated and installed Bocchino. They work well. There are other options as well. Bocchino is not the end all. Remember to Caig Deoxit G100 all parts well as the surface is coated with Silver and will tarnish fast.

You can also use Furutech, Watgate and others. I personally, just me, look for as pure a copper as I can get. No plate metal. I try and avoid colorations from plate metals.

Sometimes the Bocchino are an issue with fit. The bodies are so large they cram the insertion location. Be aware. Try a test fit before you bother to terminate.

The bocchino can take a huge guage wire and is a much firmer connection for more rigid wire.
In my experiments they seemed to raise the sq quite a bit compared to other plugs on the same wire.. worth trialing