For DVD/BD movie playback, might a pair JMLC AH425 horns produce a very good phantom center owing to their narrow directivity and if properly toed in?
You plan on being a solo listener? Maybe, if they happen to image well in your room. Beyond that you can't beat a center channel WRT having a much larger sweet spot in comparison for other than solo listening.
Rob 🙂
Rob 🙂
Indeed, parabolic is the goal with a wide horizontal and narrow vertical aspect ratio, i.e. relatively tall, narrow like a ribbon.
Yes, it ought to produce a good (tight) phantom image. With proper set up, early reflections should be favourably absent through a critical part of the spectrum and this is a good step toward seeing it isn't being blurred.
It's also unlikely these horns will produce problematic artefacts themselves, since the LeCleach profile is smooth and well thought out.
It's also unlikely these horns will produce problematic artefacts themselves, since the LeCleach profile is smooth and well thought out.
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Sure……you need to crossfire the main axis in front of the listening position……..but LR imaging suffers……everything is a compromise. Speakers with a constant wide beam width is another method and the one I prefer but does require some room treatment to the sides.
Best phantom system I’ve ever heard?…….Polk L800. Too big for my space.
This can actually improve imaging under the right circumstances.
????
Yes
Yes, a wide and deep sound stage (like Pierre's Athos TH4001 horns https://www.diyaudio.com/community/threads/beyond-the-ariel.100392/page-764 ) is what I'm hoping would be ideal, or at least the best compromise, for both stereo music and DVD/BD movies-but my main priority is mono/stereo music reproduction. But as Kevinkr cautioned it will likely require considerable room treatment to attenuate late reflections. I will soon be auditioning systems with Troy Crowe's ES450
https://josephcrowe.com/products/3d-cad-files-horn-no-1994-es450-biradial-for-jbl-2446-2-throat
and NicoB's horns. https://audiohorn.net/x-shape-horn/ https://audiohorn.net/next-gen-bi-radial-horn/
The NicoB customer has both of NicoB's horns. Hopefully, the rooms I'll be hearing these three horns in won't be too much different structurally than mine.
How would you rate those Geddes plots of NicoB's horns?
Here's g3Dahl's 425 system. https://galibierdesign.com/wa-trip-01/
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It doesn't work like that. A wide radiator can make a mess of imaging. You don't need a wide radiating speaker for a wide soundstage.
The horns linked to NicoB are all waay too narrow for my liking for phantom center.....i'd prefer out to 60 +/- 3db from 3k up to 10k. Kinda why i'm a big fan of ribbons.....
If full range ribbon speakers instead usually have a narrowing directivity with decreased frequency what midwoofer and subs do you use below ~ 3kHz?
Hi OP:
I have both a few years of exposure to motion picture auditorium sound and also lots of DIY experience/experimentation in theater sound so I think I may be unusually well suited to answering your question.
I think you misunderstand the purpose of the center speaker, and once you understand it you'll be better able to make informed choices.
In a theater the problem we faced was that listeners could be seated across a very wide area, 40' on either side of the center of the screen was not uncommon. The center speaker, and the Dolby Surround matrix (as it was called in theaters, it's first full implementation in home was called ProLogic) attempted to anchor center dialogue and effects so no matter where you sat in the theater you had the sense of sound coming from the center when needed. Consider if you are seated far left. With only 2 speakers you were much more likely to hear the left speaker as the source of the sound.
The effects in the home are the same. The center solves the issue of off-center listening. If you have only 1 seat in your watching area then I can honestly say after a great deal of listening with/without the center speaker enabled (some of this due to bad equipment that would drop the center unexpectedly) that it's almost impossible to tell if you have a center or not. Any good stereo pair of speakers that can image music in the center reasonably well will do. It's when you moving around, or lie down on your couch for instance that the center or it's absence becomes apparent. Of course, the wider apart your speakers, and or the bigger your screen the bigger the problem.
So, for designing a speaker, horn or otherwise, that replicates the center as much as possible you want to throw as wide of a "sweet spot" as possible, and this in my experience is accomplished with wide dispersion and severe control of early and direct reflections. A narrow dispersion speaker, while reducing early reflections severely and giving excellent performance in the center is not going to be a good substitute for the benefits of a center channel.
In my last real listening of commercial speakers Magico and Revel seemed to do this exceptionally well.
Best,
Erik
I have both a few years of exposure to motion picture auditorium sound and also lots of DIY experience/experimentation in theater sound so I think I may be unusually well suited to answering your question.
I think you misunderstand the purpose of the center speaker, and once you understand it you'll be better able to make informed choices.
In a theater the problem we faced was that listeners could be seated across a very wide area, 40' on either side of the center of the screen was not uncommon. The center speaker, and the Dolby Surround matrix (as it was called in theaters, it's first full implementation in home was called ProLogic) attempted to anchor center dialogue and effects so no matter where you sat in the theater you had the sense of sound coming from the center when needed. Consider if you are seated far left. With only 2 speakers you were much more likely to hear the left speaker as the source of the sound.
The effects in the home are the same. The center solves the issue of off-center listening. If you have only 1 seat in your watching area then I can honestly say after a great deal of listening with/without the center speaker enabled (some of this due to bad equipment that would drop the center unexpectedly) that it's almost impossible to tell if you have a center or not. Any good stereo pair of speakers that can image music in the center reasonably well will do. It's when you moving around, or lie down on your couch for instance that the center or it's absence becomes apparent. Of course, the wider apart your speakers, and or the bigger your screen the bigger the problem.
So, for designing a speaker, horn or otherwise, that replicates the center as much as possible you want to throw as wide of a "sweet spot" as possible, and this in my experience is accomplished with wide dispersion and severe control of early and direct reflections. A narrow dispersion speaker, while reducing early reflections severely and giving excellent performance in the center is not going to be a good substitute for the benefits of a center channel.
In my last real listening of commercial speakers Magico and Revel seemed to do this exceptionally well.
Best,
Erik
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So, this means that even with a pair of narrow directivity horns, like the JMLC 425, if I'm ~ 11 ft away, viewing alone, seated upright and within a ~ ? ft of the toed-in speakers then I'd have no apparent need for a center speaker?
The JBL Everest DD55000 had an interesting horn profile which they marketed as giving a wide sweet spot due to the horns dispersion.
Car audio folks use a similar technique with a pillar mounted tweeters to account for both seats being non central.
Rob.
Car audio folks use a similar technique with a pillar mounted tweeters to account for both seats being non central.
Rob.
If the intent and purpose in this use case is to anchor center channel content to the screen?…….yes. But now you’ve also moved the left and right channel content including the spatial component to the screen……in using the narrow directivity to reduce early reflections from stereo music playback, you’ve effectively collapsed the multi channel presence and congested the soundstage.
Now some folks…..and many to excellent degrees of success would simply add front WIDE and/or HEIGHT speakers to such a system using multichannel algorithms to regain the spatial presentation. Today’s spatial and Atmos music content can work very well in these instances too…..but it’s hit or miss currently as the way these tracks are mixed has no real standard…..more of playtime have fun thing going on…..but many or dare I say most engineers are doing an excellent job of it.
If you sit significantly off-center, either to the left or right of the central listening position, you end up much closer to one of the speakers. The other speaker is farther away (resulting in a time delay) and, in most cases, sounds quieter due to the increased distance. These two factors often lead to a shift in the soundstage toward the closer speaker or even cause the sound to "stick" to it. Speakers with wide dispersion tend to have a broader sweet spot, but they are not immune to this effect—the nearer speaker still sounds louder.
To reduce this effect, you can make the farther speaker play louder while lowering the volume of the closer one. This adjustment primarily applies to mid and high frequencies since bass is more evenly distributed throughout the room (excluding bass modes for now).
You can achieve this if you have speakers with relatively narrow and consistent directivity (or a very gradually narrowing pattern) and aim them so that each speaker’s axis points to the farthest opposite seat on the couch (toe-in before the listening position). This way, when sitting at the far left or right position on the couch, you hear the on-axis sound from the opposite speaker (maximum dB) and, say, a 35- or 45-degree off-axis sound from the nearer speaker (significantly lower dB but maintaining a balanced frequency response, or with some high-frequency loss).
Of course, there will still be a delay from the farther speaker, but overall, you get a significant stereo effect (or a spacious sound in movies). Speech intelligibility in movies remains well-preserved because you hear a similar frequency response from both the left and right speakers in any seating position. The soundstage will still shift toward the nearer speaker, but the effect won’t make it feel like all the sound is stuck to one side. By adjusting the speaker toe-in and the size of the listening triangle, you can achieve a very stable soundstage from any position on the couch. Additionally, the effect remains smooth when moving from the central position to the sides.
I guess the issue is the definition of "relatively narrow." My experience with say ESL's has been poor, while the two brands I used for reference, above, has been very positive.
I would say if you sit in a narrow channel in the center of the TV the need for a center is greatly reduced. Toe in/toe out has more to do IMHO with side reflections. The best angle for the speakers will have a lot to do with how close to the side walls they are and how much room treatment is present.
It is true that there is some head related transfer function (HRTF) which makes a center channel theoretically better. Your head occludes and causes some comb filtering with a phantom center which is not present when you have a true center channel. Same is true for mono music BTW, but in practice I absolutely cannot tell the difference in my setup.