directional speakers

treepmeyer

I apologize, I now realize the importance of the specifics of your post. My responses are related to 2D and Front Imaging: not ‘3D from 2D’ which is Bacch4MAC’s objective.

I just looked it up and realized Bacch4MAC is what my friend wanted me to go to a demo of in Princeton (45 minutes from us). After a glance, I declined, thus I have never heard/experienced their solution in use.

I think Narrow Dispersion is the wrong way to go.

Imaging, wide and precise starts with the engineering, then IF vinyl, the cartridge's wide channel separation and tight center balance make a big difference for imaging: both before you send the signal to the speakers. Digital (CD, Streaming -not me) already produces separate L/R, again, the engineering making the difference. The recorded signal is producing better or worse imaging prior to the pre/amp/speakers.

Tweeters are the narrowest dispersion, thus they need to be directed at the listening position, both horizontally and vertically to seated ear height, (slanted front face or leaning the speaker back solves this) and has the advantage of altering the initial reflections off the floor and ceiling and eventual reflections off the rear surfaces.

Horns, for tweeters and midrange typically, are designed for controlled directivity, oriented correctly, go for wide horizontal dispersion, combined with limited vertical dispersion. (as well as horns increase in a driver's output (thus high sensitivity) Check the Polar Graphs to see both horizontal and vertical dispersion.

Toe-In, and Angle of the drivers are important. As noted, tweeters need to be aimed directly at the listener. Wide dispersion will maintain better frequency balance better than narrow directivity.

Alternate Toe-In (forget spikes). For two listeners, I aim the left speaker directly at the right listener; right speaker directly at the left listener. This uses the DBX Imaging Concept: you are nearer one speaker for volume and you get more direct dispertion/volume from the other side.

Rear Wall/Corner/Ports. I am no fan of ports, if so, front. Distance from corners can be messed with, and measured via sound pressure meter and cd test tracks (not LP)

By the time we get enough money for good equipment, and good source material, and enough free time: we are old enough that our lack of sensitivity to high frequencies has begun, and will continue to diminish, thus the distribution of the narrowest frequencies are the ones we want to preserve, perhaps boost a bit and a bit more as we age.

Ignore the Space (at first)

One Listener, always dead center, narrower may be beneficial.

A bit OFF Center (i.e. two listeners): narrower may be detrimental.

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Measurements, published specs:

frequency balance (i.e. 45 hz to 35000 hz +/- 3db)

sensitivity (1 watt/1 meter away i.e. 89db)

are taken directly facing the speaker. (i.e. direct toe-in), most often in a space with zero reflections.

On/Off Axis (infrequently given by maker, mostly revealed by reviews with test reports). Polar graphs of individual drivers, and assembled speakers exist.

On/Off Axis shows the ’drop off’ of various frequencies as you sit off axis (off center), the narrower frequencies ALWAYS dropping sooner off center, and producing less volume than other frequencies. Horns, multiple tweeters, acoustic lens ... are meant to minimize horizontal drop off of narrow frequencies (often controlling/limiting vertical distribution)

Sit Dead Center: toe-in: aim the speakers other than directly at listening position,

narrow frequencies will be weaker in volume than wider frequencies. Detrimental to both frequency balance and Imaging.

Sit a bit off center:

narrow dispersion: the highs are weaker than other naturally wide frequencies, and Imaging is altered detrimentally.

wide dispersion: the highs are closer to the other naturally wide frequencies, and Imaging will be better than narrow dispersion.

Alternate Toe-In. DBX Wide Imaging System.

Aim left speaker directly at right position. Aim right speaker directly at left position. Each position gets ’more’ volume via directivity combined with ’more’ volume via distance to nearest speaker. Wide imaging is created. Great for 2 listeners and very important for home theater

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Imaging (not frequencies)

2 channel stereo: All is phantom, the engineers varying volume side to side, phase, other engineering methods.

narrow dispersion: successful imaging will be limited to dead center

wide dispersion: successful imaging will be extended a bit off center as well as center.

You, wherever you are, are not aware of whether distribution/imaging is from narrow or wide dispersion drivers, you only hear what that specific position receives. IOW, you are not aware if the distribution is narrow or wide, just whether the imaging is poor or good.

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Now Consider the Space (reflections off floor, ceiling, side walls, rear wall)

and Toe-In as it relates to the speaker’s directivity, and the space’s alteration of the speaker’s measured dispersion, NOW in a space with reflections..

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Get thee a SPL Meter, Tripod, and a Test Tone CD (not LP). Know what you are dealing with, what you are getting, at that location, in that space.

Oh yeah, old fashioned features: a balance control, tone controls, equalizer, or my beloved speakers with level controls combined with those features.

Then, adjust for your preferences and/or needs i.e. your hearing ability as revealed in testing.

Lastly, remote balance, a gift you give yourself.

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treepmeyer

thanks for acknowledging my input.

I don't know anything about what you are doing, I just write for you and others I imagine who are following: to share what I have experienced, perhaps to get you to try that alternate toe-in for instance, try leaning your speakers back to aim the tweeters, and alter the floor and ceiling reflections, perhaps buy a sound pressure meter, test cd, a tube tester, i.e. give yourself tools to get the most out of what you have or might buy.

Especially speakers, always the biggest difference, and understand you have to find how they best fit 'that' space.

I try to be organized and clear enough when I write, perhaps comes off as 'you should', but it is really 'you might want to try this'.

treepmeyer

"I just bought a Bacch4Mac bundle and am thinking of upgrading speakers.  Theoretica recommends speakers that are more rather than less directional.".

Perhaps you could summarize the beneficial theory you are pursuing.

Audio Presentation: 2D Stereo; 5.1 Directional; 3D Enveloping

Live sound is generally ‘front stage based’ (except ‘surround theater’ like Cats), presenting 2D directionality (varying greatly with seat location). Conveying the sense of a particular space, but almost never experienced as surround sound.

I listen to ‘Front Stage Based’ 2D (live and recorded/reproduced). Quality equipment and speakers for fidelity. Two Speakers to provide Stereo Imaging. (great Mono fidelity already existed). The Stereo Imaging is greatly affected by the Space the Speakers are in.

Bacch4MAC (3D from 2D). Nyet, a blunt no from me. I lived thru the era of unsuccessful ’enveloping sound’ attempts, Quad etc.

I have never liked or wanted ’stereo everywhere from 2 speakers’, like Bose and others attempt, and not a big fan of attempts of 3D from 2D, like Bacch4MAC is.

It should be noted: 3D Immersion from 2D is different than Dolby 5.1 ‘directional sound’ (developed for Video).

Video’s Sound: I used to grab the speaker wires out of old CRTs, hook up better speakers, realizing the audio signal was far better than what we heard from the dinky speakers within. I was thinking about improved fidelity, not directionality

Dolby 5.1 is ‘improved front imaging’ via center speaker along with better front speakers spaced widely apart: combined with directional effects of specific sounds, placed here or there by programming, to be produced by separate additional directional speakers, for often unseen sources i.e. helicopter from rear left …. The ‘.1’ adding a sub-woofer for a Dinosaur Stomp. Dolby is enhanced directionality, not 3D immersion. (excepting battle scenes, earthquakes, ... still created by specific programming for INDIVIDUAL directional speakers, not 2. Individual Room Correction is adjusted by specific locations of 5 speakers and 1 sub, volume matched by ear or automatically volume matched by ’In-AVR’ signals and microphone provided. Those adjustments are based on and re-produced from/to the center listening position: 1 person, dead center.

‘Sound Bars’ attempt, like Dolby 5.1 to produce improved directionality (not 3D immersion) via ‘processing tricks combined with special drivers within.’

 

Note: omitting a center channel speaker while listening to 5.1 totally eliminates the sounds specifically programmed for the center speaker, i.e. most dialog compromised). No Center Channel Speaker: 5.1 content: Changing the AVR to 2 Channel Stereo very often improves the primary sound as center programmed sounds are added equally to both FL and FR

Now, I watch a lot of Video on my small Dolby 5.1 Home Theater.

VIDEO: I concentrate on Improved Front Imaging: 2 or 3 persons sitting on a couch: (3 persons: the Majority or 2 persons the Entire audience off-center.

Or, 1 person, i.e. proximity to an end table). the entire audience off-center, Important for both front 2D Imaging (stereo: no center or rear speaker/content) and the improved front 2D of Dolby 5.1. 2.1 simply adds a subwoofer to 2D Stereo. .

My Vintage DBX 100 speakers, are designed specifically to create a wide front stereo image. (I call the DBX 100 solution ‘cross toe-in’). Aim the Left Speaker toward the right side/Aim the right speaker to the left side. Stereo Imaging is widened based on: relatively equal volume l/c/r via opposite side increased directionality combined with volume from near side proximity. DBX 100’s have 3 tweeters (front/side/rear) to solve highs that have too narrow dispersion to work via ‘cross toe-in’.

Pseudo 5.1 (created from recordings that were not specifically made for 5.1) very often sounds better when the AVR is changed to 2 Channel Stereo. Often selecting ‘direct’ changes Pseudo 5.1 to 2 channel. I find much content is Pseudo Surround.

 

from their site (emphasis by me):

**BACCH-ORC is the most advanced room correction technology today. Unlike any other commercially available room correction system, BACCH-ORC relies on quick in-ear (binaural) acoustic measurements, millimeter-resolution head tracking, and cutting-edge algorithms derived from years of psychoacoustic research, to produce and apply individualized optimal room correction (ORC) FILTERS: that elevate any stereo loudspeaker playback system to its ultimate level of transparency".

"BACCH-dSP is a 3D audio powerhouse application for mixing and rendering 3D binaural audio over loudspeakers and headphones.

At the heart of BACCH-dSP is BACCH® 3D Sound, a proprietary technology developed at Princeton University that allows the listener to experience stunning virtual reality 3D imaging using only two loudspeakers."

the in-ear microphones are : "used to generate personalized digital filters for BACCH® 3D Sound". (from those speakers, in that space, at the in-ear microphone's specific location.

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Without reading about Theoretica, I presume, by OP's statement, that NARROW DISPERTION speakers are recommended i.e. narrow is best for the in-ear microphones reception NEEDED to produce the filters to create Individualized optimized room correction.

Playback via those filters want to be reproduced by the same narrow dispertion speakers.

This is definitely designed for 1 person, centered, keeping their head/ears where they were when the in-ear microphones received the in-room signal to create the filter for that specific room.