Is a higher directivity speaker 'coloring' the sound?

[Mort]

For many months now, I've been listening to two very different directivity speakers, Philharmonic Audio HT's with an AMT ribbon and the coaxial Genelec 8361a's. The biggest difference (regarding directivity) is the HT's sound more spacious or to me 'ethereal'. The Genelecs have a much clearer but smaller soundstage. Both of these experiences are predicted and expected by the measurements of the individual speakers. Neither is 'better,' but I've come to hear the extra reverb of the Philharmonic Audio speakers as a 'coloring' which I sometimes like, especially on acoustic tracks, but overall prefer the Genelec cleaner sound.



For the record, I think directivity is a commonly confused speaker measurement. Audioholics does a pretty good job of explaining in this first of a three-part video series.

This video explains loudspeaker directivity, which is how a speaker disperses sound in different directions (0:42). It covers:

• Definition and Measurement: Directivity is measured using polar plots and can be quantified by the directivity index (DI), where a low DI means wide dispersion and a high DI means narrow dispersion (2:30, 2:48). Measurements are often taken at various angles around the speaker (3:15).
• Ideal vs. Realistic Directivity: The video shows ideal directivity plots, noting that perfectly constant directivity across all frequencies is not feasible, especially at low frequencies (7:04). A realistic constant directivity speaker widens its response at lower frequencies but maintains control in mid-range and treble (7:31).
• Directivity Matching: This refers to how well the dispersion of different drivers (like woofers and tweeters) aligns at their crossover point (11:15). Mismatches cause the sound to change dramatically when listening off-axis, affecting reflections in the room (11:36, 12:55).
• Causes of Mismatches: The size of the driver (piston diameter) is a primary factor in when it starts to "beam" or narrow its dispersion (15:32). A common mismatch occurs when a small tweeter (which is omnidirectional up to about 3 kHz) is crossed over with a larger mid-bass driver that has already started to narrow its dispersion (16:40).
• Directivity Control: This involves efforts to restrict or shape the sound radiation (21:06). Examples include using waveguides or horns for narrow dispersion, or advanced DSP with multiple drivers for adjustable dispersion (3:03, 20:31). The video also discusses how different directivity patterns affect the listening experience in a room, such as phantom imaging and spaciousness (24:10, 39:02).

 

[boxerfan88]

I think there is an element of personal preference in this.

Back then when I was shopping for my speakers, I listened to Perlisten S7t, the soundstage wasn’t big (stayed within speaker boundaries), imaged superbly well and at loud levels gave me a feeling the singer was inches from my nose.

Eventually I bought the KH310 with wider directivity. Soundstage is a tad larger (outside speaker boundaries) even when toed-in, imaging a little less sharp. I prefer it this way.

 

[Pareto Pragmatic]

I think of it as directivity changing how your room colors the sound. More or fewer sidewall reflections, most commonly. Generally, how the sound dispersion from the speakers interacts with the room as a whole.

10'/3m into my room for speakers, wide is fine. Half that distance or less, I definitely want narrower to get similar levels of room coloration.

the HT's sound more spacious or to me 'ethereal'.

The more sidewall reflections I get, the more I hear similar results. The cost is more distortion. So balance to taste.

 

[Toni Mas]

For many months now, I've been listening to two very different directivity speakers, Philharmonic Audio HT's with an AMT ribbon and the coaxial Genelec 8361a's. The biggest difference (regarding directivity) is the HT's sound more spacious or to me 'ethereal'. The Genelecs have a much clearer but smaller soundstage. Both of these experiences are predicted and expected by the measurements of the individual speakers. Neither is 'better,' but I've come to hear the extra reverb of the Philharmonic Audio speakers as a 'coloring' which I sometimes like, especially on acoustic tracks, but overall prefer the Genelec cleaner sound.

May i ask what make you think that directivity is the reason why these speakers sound "different" ( I prefer to avoid the term coloration)?

 

[Kal Rubinson]

The biggest difference (regarding directivity) is the HT's sound more spacious or to me 'ethereal'. The Genelecs have a much clearer but smaller soundstage. Both of these experiences are predicted and expected by the measurements of the individual speakers.

The answer is to combine the higher directivity with multichannel.

 

[sfogg]

The answer is to combine the higher directivity with multichannel.

And make the room as dead as possible as the surround will reproduce the ambiance and spaciousness in the recording. No need for the room to try to fill that in as needed for stereo.

 

[mj30250]

The answer is to combine the higher directivity with multichannel.

Agreed, but in my experience this is an answer that is in itself in need of an answer. Much of what I prefer to listen to does not exist in native multichannel, particularly in lossless formats that are readily accessible.

I've played around with upmixers several times, and each time I've found the results to be...mixed. Perhaps I'm just doing it wrong.

 

[ppataki]

I think of it as directivity changing how your room colors the sound. More or fewer sidewall reflections, most commonly. Generally, how the sound dispersion from the speakers interacts with the room as a whole.

10'/3m into my room for speakers, wide is fine. Half that distance or less, I definitely want narrower to get similar levels of room coloration.




The more sidewall reflections I get, the more I hear similar results. The cost is more distortion. So balance to taste.

And it is measurable too
Taking a look at the IR curve provides insights about reflections - the wider the dispersion (=less beaming) the higher those reflections will be
I have posted measurements about this phenomenon here a few times, if anybody is interested I can look it up

 

[DVDdoug]

I agree it is largely a matter of taste...

If you want "accurate studio sound" then you want a dead room and constant directivity, or "flattish" slightly downward sloping response. Of course the deader the room the less directivity matters.

I like a little more room sound. I've had my speakers in a dance hall a couple times and the natural big-room reverb coming from all directions sounds great! At home I use a "hall" or "theater" setting on my AVR for some delayed reverb from the rear.

The biggest difference (regarding directivity) is the HT's sound more spacious or to me 'ethereal'. The Genelecs have a much clearer but smaller soundstage.

My intuition tells me that omnidirectional speakers make a bigger but less precise soundstage.

And I saved a quote from Amir about dipole speakers:

A dipole speaker surely generates spatial effects that are not real and were never heard in the studio. Combine two such speakers and you are just dealing with fantasies as opposed to mimicking what someone may have setup.

 

[suttondesign]

And I saved a quote from Amir about dipole speakers:

Amir's quote is correct that the effects of dipoles were not heard in the studio, but he misses Siegfried Linkwitz's point about how they are heard by the listener. His idea is that the brain sorts out the late reflections caused by properly-set-up dipoles. So the reflections are certainly occurring, but the listener's brain presents the first-arriving sound as the primary source. Until you hear his designs, you can't appreciate the dramatic effect they have. That said, with tv dialog, they're awful off-axis. He didn't intend them as home theater speakers.

 

[sfogg]

Agreed, but in my experience this is an answer that is in itself in need of an answer. Much of what I prefer to listen to does not exist in native multichannel, particularly in lossless formats that are readily accessible.

I've played around with upmixers several times, and each time I've found the results to be...mixed. Perhaps I'm just doing it wrong.

Which ones have you used? Many are really tuned for movies and don't work as well for music. There are a few built for music that can work well though. Logic 7 and DPLII arer good but are only on older equipment. Both have adjustments to let you tailer the results to you tastes, Logic 7 has many adjustments to do that. A used Lexicon MC-8 would give you both, along with other things such as Panorama (interaural cross cancelation) and they sell for little money now. A DC-1, DC-2 or MC-1 would give you L7 and Panorama but not DPLII and they are little money now. All the Lexicon's will also give you bass management, time alignment, an SPL aware loudness function and some really handy things like a Tilt control.

I just started using QuantumLogic Surround, and it is very good but it is incredibly demanding to setup for use in a home.

 

[Kal Rubinson]

I've played around with upmixers several times, and each time I've found the results to be...mixed. Perhaps I'm just doing it wrong.

Understood. Good room correction would be better.

Amir's quote is correct that the effects of dipoles were not heard in the studio, but he misses Siegfried Linkwitz's point about how they are heard by the listener. His idea is that the brain sorts out the late reflections caused by properly-set-up dipoles. So the reflections are certainly occurring, but the listener's brain presents the first-arriving sound as the primary source.

Indeed, two of the best multichannel systems I have heard consisted of large planar dipoles. In each case, the listener was in the near field completely surrounded by the speakers but the speaker array was situated in a much, much larger room.

 

[Chris A]

And make the room as dead as possible as the surround will reproduce the ambiance and spaciousness in the recording. No need for the room to try to fill that in as needed for stereo.

If you've got full-range directivity control down to the room's calculated Schroeder frequency (~100 Hz in my listening room), then you actually do not need to make the room quasi-anechoic. Here is a RT plot from REW with the microphone at the front loudspeaker (1st-gen Jubilee) with absorption on the floor between the front baffle and the microphone capsule:

I find that I don't need to deaden the room any more that what you see, above, to plainly and clearly hear phase corrections in all loudspeakers (including the TH subs) with the room reflections as you see.

But then again, almost no one here has loudspeakers all the way around that hold their polars down to the room's Schroeder frequency (where directivity basically no longer matters).

JMTC.

Chris

 

[sfogg]

If you've got full-range directivity control down to the room's calculated Schroeder frequency (~100 Hz in my listening room), then you actually do not need to make the room quasi-anechoic. Here is a RT plot from REW with the microphone at the right front loudspeaker (1st-gen Jubilee) with absorption on the floor between the front baffle and the microphone capsule:


But then again, almost no one here has loudspeakers all the way around that hold their polars down to the room's Schroeder frequency (where directivity basically no longer matters).

Nice setup, I was just reading about your mod to the K402 yesterday, very cool.

Totally agree that it is very difficult to keep polars consistent all around. I have LaScala bass bins for L/C/R with K510/44xts for the top end. With another 14 speakers in the room (and 2 subs) which don't have nearly the same control. Acoustic treatments on all walls and the ceiling with with thick velvet drapes over that. I want it as dead as possible.

 

[Chris A]

With another 14 speakers in the room (and 2 subs) which don't have nearly the same control. Acoustic treatments on all walls and the ceiling with with thick velvet drapes over that. I want it as dead as possible.

Yes, the problem with Atmos increased channel setups is that you basically have to trade off directivity control due to room real estate limitations. I could only imagine having the elevation and midpoint-wide loudspeakers having directivity down to Schroeder. Even I would object to K-402-MEHs hanging from the ceiling and back surrounds, etc.

Multichannel SACDs and PCMs (a little over 250 of them in my library) sound quite live as-is. (Classical piano is particularly good.) Going to Atmos, etc. seems pointless and since I don't really watch Marvel superhero movies--there is presently little reason to add more channels beyond 5.1 in my case, I've found.

I found that phase flattening/time alignment of all channels is critical, though, in addition to flattening amplitude response to ±2 dB (psychoacoustic smoothing) all the way around--not counting listening room modes.

Chris

 

[sfogg]

I am not using Atmos. Thise extra channels are used for 2,5.1 and 7.1 sources. If you can easily add rears (even for a test) they can be very effective in helping with envelopment and making everything more cohesive.

 

[Chris A]

I suppose you're saying that these charts (from Toole 1st Ed,) really aren't telling the story, eh?...

...comparing configurations "E" (full 12-channels) vs. "I"/"L" (ITU 5.1) in the second figure, above.

Chris

 

[SSS]

For me it is as easy as it can be. Thus meaning there is no ideal polar response. The sound distribution is always modified by room reflections and absorbtion. Nothing new of course. So it may be wise to choose the speaker with a certain polar response which gives best sound result in the intendet room. More side reflections widens the sound stage. No side reflection, sound stage is always between the speakers. Therefore it is a personal preference what someone like best. Myself I live good with the sound reflections from my room because it is natural. If one wants just only to hear the mix itself then best use closed earphones.

 

[sfogg]

I suppose you're saying that these charts (from Toole 1st Ed,) really aren't telling the story, eh?...

Not the whole story, no. Spaciousness goes below 100hz for example, see the work of Dr. David Griesinger.

along with numerous other papers. Including multiple papers on # of loudspeakers for playback to increase spaciousness and envelopment.

But the proof is in the listening. If you can setup a temporary pair of rears you might consider giving it a try. You just might find it fills in holes you didn't even realize you have. I did. Or maybe you won't. I went to 7.1 25+ years ago and it made a nice improvment on music in all of the rooms I've used it in.

You might note that Dr. Toole's system is well beyond 5.1 too....

 

[Chris A]

Thanks, that was precisely what I was looking for...

My awareness of Griesinger's work goes back to my own experiments with phase flatness. That experience was astounding, and came after I read his presentation on clarity.

Chris