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Ishiwata Toe In (Extreme Toe In), have you tried this?

StigErik

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Joachim Gerhardt (Audio Physics, Suesskind Audio) had some interesting thoughts about toe-in almost 30 years ago, find the link to it below. Not very scientific, but still interesting I think. One might argue that placing the listening position close to the rear wall is not a good idea, but it does have some advantages is the low bass. It can work well with some absorption behind the listening position.




Bild5.jpg
 

LTig

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What Hugh Brittain proposed was a way of widening the 'sweet spot'. A listener on the left would hear more of the left loudspeaker, but would be more on-axis to the right 'speaker, somewhat restoring the central image. Ditto for a listener on the right. Note that loudspeakers of the 1950s had a fairly narrow HF dispersion due as much to the cone tweeters then generally used. As image position is influenced more by higher frequencies than lower, this makes a lot of sense, and was a way of ameliorating the criticism of stereo that it was only suitable for one listener sitting in the centre.

What this shows is that there's nothing new under the sun, and old techniques are constantly being 'rediscovered' and attributed to later publicisers.

S
Excactly. It makes sense e.g. for nearfield monitors at a wide mixing console so the mixing engineer can move to the left and right of the optimal listening position to operate the controls without loosing the stereo image. You need speakers with smooth off axis response for it to work properly.
 

Digital_Thor

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I find it interesting to see them use Q acoustics and Dali speakers as examples, when they both have a none smooth or linear response, both on and off axis.
Using a much more well measuring speaker from KEF or Revel, would in my view make more sense to toe in, if sidewall reflections are too much - even with first reflection damping.
 
D

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Ishiwata toe in or extreme toe in where the speakers cross over in front of the listening position.

I have done this. I had a room where I worked at a desk, close to and centered on a long wall. The room was 40' wide and 11' deep, so strange size. I was constantly moving at the desk, both side-to-side and forwards and backwards. To relieve the boredom, I had two cheap speakers. They were approximately 4' from the front wall, and 8' apart, aimed directly at each other. I sat directly between them.
I experimented somewhat, sitting slightly ahead of dead center and slightly behind dead center. There seemed to be no difference; both soundstage and image were not only acceptable, but quite good and definitely in front of me. Moving side to side, however, shifted the soundstage accordingly ... and predictably. I got used to that.

I can't comment on further use of the arrangement, because my positioning, and the positioning of the speakers, was quite restricted. However, I would have no compunction about experimenting with this same setup in a regular house. I have often thought that a center speaker would solve the L-R instability, but I just never got around to testing that.

I can be lazy. ;)

Jim
 
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Blumlein 88

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I've used it some. I've mostly used panel speakers in my life. Some of those are rather directional. I usually had them crossing a little in front of the LP. I done it that way, at the LP and slightly behind depending upon the speaker and room. It is not some big revelation or insight.

Now extreme toe in was specified by was it ADL speakers, anyway, back in the 80's or 90's they suggested very wide spacing and firing the speakers at like just in front of the opposing speaker. I think they had a different directivity as well. The claim was you got a very wide area over which the stereo effect was good for several listeners and their design had good FR used that way.

I also remember in college dorms it was common to put speakers at opposite ends of the dorm room (those were small rooms back in those days) firing at each other. A sort of a headphone effect could be obtained and it wasn't bad. The rooms were usually not long and very narrow. So lots of sidewall reflections kept that from being too much of a headphone effect.
 

dwkdnvr

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If I recollect Grimm recommended severe toe-in crossing a metre in front of the mlp, I think there was even an option in the software to optimise,
it’s here under ‘positioning’.

Keith
Earl Geddes suggested the same setup for his Summa and related speakers, I believe. Back when I had Unity horns in a way-too-small room I used this setup and it really did work very well, but I suspect you need speakers with fairly good/uniform dispersion characteristics (less of a problem now than 20+ years ago when Geddes was suggesting it)
 

raindance

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This is also useful if you need to use a pair of speakers placed either side of your display for the center channel due to layout issues. It maximizes the sweet spot. Of course, it also adds comb filtering effects so don't move your head too much...
 

Digital_Thor

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Earl Geddes suggested the same setup for his Summa and related speakers, I believe. Back when I had Unity horns in a way-too-small room I used this setup and it really did work very well, but I suspect you need speakers with fairly good/uniform dispersion characteristics (less of a problem now than 20+ years ago when Geddes was suggesting it)
His speakers have way different DI than most speakers. So again, I do not think you can fully use the same approach in all situations.
You can fiddle around with your speakers and try it all out. But I find that my coax speakers play better when pointing a bit forward rather than a lot inwards - especially since I have a TV in the middle and open space on the sides of the speakers. So I guess..... compromises :D
 

Duke

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... extreme toe in where the speakers cross over in front of the listening position [have you tried this?]

Yes. I was an early disciple of Earl Geddes (worked with Earl for a while on the development of the Summa). Ime crossing the speaker axes in front of the listening position works well when the radiation pattern is well-behaved.

Aside from the relatively wide sweet spot due to time/intensity trading, the arrival of the first significant lateral reflections are pushed back in time, which is a disruption of the "small room signature" of the playback room. These first lateral reflections also arrive at the opposite ear which minimizes their coloration effects and improves the ear's ability to extract spatial information from them. The net result is imo an improvement in both sound quality and spatial quality, the trade-off being that you lose the soundstage-broadening effect that comes from having strong early same-side-wall reflections.

Here are two such setups (using speakers I designed), and in both cases the toe-angle is 45 degrees (or thereabouts); underneath the grille cloth of the first is a 90-degrees-horizontal constant-directivity horn crossed over to a 12" prosound woofer at the frequency where their patterns match in the horizontal plane:

PhantomCenter-002.jpg


TimeIntensityTrading.jpg


In both of these systems the center vocalist is still approximately in the center from the location where the photo was taken. The owner of the speakers in the first picture got rid of his center channel speaker because he no longer needed it and liked the sound quality and spatial quality better using phantom center mode. (That being said, for anyone with a hearing imbalance, using a center channel speaker makes sense in a home theater system imo.)

One of the more interesting experiences I had with this configuration was with a customer in the Phoenix area who had owned SoundLabs for over two decades. He wanted speakers that didn't need as much power so he could use cooler-running amps, but he didn't want to take a step backwards in sound quality or spatial quality. I'm also a SoundLab dealer so I knew all too well what I was up against.

We moved his SoundLabs into another room and I set up my speakers (large bipolars) with the axes cross-crossing in front of the listening position. He was highly skeptical to say the least, and I had to tell him "let's just try it this way". We ended up listening to many dozens of recordings over the course of the weekend, and he was impressed enough that he placed an order(!!!). We put the SoundLabs back in his room and I packed up my speakers and drove home.

Then about two days later he cancelled the order. Here's what happened: He had re-positioned his SoundLabs to replicate the extreme toe-in geometry I'd used for my speakers, and the SoundLabs had now moved out in front by enough of a margin that he no longer wanted to replace them with mine. Dangit! This was fifteen years ago and to the best of my knowledge he's still using SoundLabs set up that way.
 
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Thomas_A

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I use almost 45 degree angle and speakers are designed with that in mind. It creates a stable phantom center and reduce the level of reflection from nearest walls.
 

ernestcarl

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I've done this before on and off for my couch's main front LR speakers, but have reverted back to on-axis. I figured, since it's only me here majority of the time anyway, I'm better of using DSP presets to adjust the interaural level and time difference and add a bit of EQ for when I want to listen off-axis. The main side-effect was laser imaging focus esp. vocals were reduced/blurred slightly at the center MLP. Also, the slightly better interaural volume level difference when sitting far off the MLP does not fix at all the time difference -- which is way, way more important.

Incidentally, my rear surrounds for the front desk in the room crosses acutely due to them being used as surrounds for the couch as well in the rear of the room room -- in other words, it wasn't really designed on purpose to be that way. Luckily, left-right localization is still mostly as expected.
 

Kevin1956

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According to this article in the Dope from Hope newsletter by Paul Klipsch, the benefits of 45 degree toe in on an enlarged stereo “sweetspot”, have been known since at least 1934. “Ishiwata Toe In”? I suspect he knew of the same research as PWK, as well as PWK’s work, and also agreed with the conclusions.

 

MattHooper

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According to this article in the Dope from Hope newsletter by Paul Klipsch, the benefits of 45 degree toe in on an enlarged stereo “sweetspot”, have been known since at least 1934. “Ishiwata Toe In”? I suspect he knew of the same research as PWK, as well as PWK’s work, and also agreed with the conclusions.


I had always figured when I saw extreme toe in at shows, that it was to widen the sweet spot (which makes sense given you have multiple listeners at shows).
 

GXAlan

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Big Marantz fan and I owned the PM-10 and SA-10. Ken Ishiwata actually explained that the excessive toe in was only for demos to allow more people to experience good sound but it was not his recommendation for individual listeners.
 

StigErik

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Here’s one of my setups. Close to 45 degrees toe-in. The speakers are good old Magnepan 1.5s (with active XO and DSP of course ). Soundstage is very wide, with no loss of «pinpointing» or stable centre image. That’s entirely my own subjective experience of course.

.
IMG_0442.jpeg
 
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GXAlan

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Big Marantz fan and I owned the PM-10 and SA-10. Ken Ishiwata actually explained that the excessive toe in was only for demos to allow more people to experience good sound but it was not his recommendation for individual listeners.


Found this. It is an interview with Ken Ishiwata and the caption for the speaker photo states:


At the venue, there was a large listening booth individually dedicated to Ken Ishiwata's demonstration, and many visitors were crowded each time. The reason why the speakers are extremely toed in is to make as many people as possible experience the sound stage at an event where a large number of listeners gather.

I am sure I have seen this also confirmed in an YouTube interview with KI somewhere, but I cannot find it.
 

tmuikku

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My subjective experience with playing around with the room acoustics is not the same. The effect of changing a speaker's toe-in is very obvious on measurements, and it can be heard. But how do I know what to expect from say - a reflection off the back wall arriving 12 ms after the direct sound with a level of -15 dB? How does that sound? What should I be expecting?
Hi, if you are interested fooling around with this kind of stuff see here https://www.diyaudio.com/community/...practical-tips-and-tricks.406608/post-7535307
In short, if you expose yourself to how reflections sound like you have a chance to actually hear them and have an opinion about it. And to do this you'd need to figure out some listening experiments and I've posted some behind the link for starters.

If you really are curious and start to do listening tests, that might seem crazy to family members and neighbours, you'll find out it's possible to hear a reflection, and then just by turning your head or move a little to mute it. Looking at it might mute it, while turning your head exposes it!

What's the takeaway? you can npw stat reasoning with hour perception. For example, if you can't hear it does it still affect somehow perceptually? is it better to hear it or not? If it changes with head position for example, where did it go, why don't I perceive it as it supposed to be still there as the room and speaker didn't move? Point is, you have now a chance to actually listen this stuff and form an opinion about it, as already said, start reasoning with your own perception.

Basically it's all just developing listening skill, putting your mind on what you perceive, get to understand some of your own auditory system which is very important in my opinion, only when you understand what you perceive you can now optimize your system in your room. I like to think what we perceive is what our own auditory system lets into existence into our conscious mind we think with. Of course, the room and speakers matter but only through adjusting them to align with your auditory system, in your reality of audio in your room!:) I think we all do this naturally already, but really paying attention, doing listening exoeriments and reasoning on them is the key.

Details of singular reflection like -15db at 130deg azimuth with 12ms delay are meaningless in a way, easy to understand reading them, but unless you can actually hear them you do not know if they are useful or not, and in which context, and whether you like it or not, and whether it happens or not with ypur systrm. What if you have only -14db and only 11ms and it's 180deg instead of 130deg, what it supposed to do, should it disappear or just get quieter or how it should be perceived?? is it better or worse, or does it matter at all in your room with our speakers and what you want to hear? Is it something you want to deal with anyway, why not just listen to music? :) The details are useful to point into right direction, but eventually you'd have to have opinion about perception to know if it was what you are looking for or not.

Improving listening skill is a way to figure out all of this, by yourself in your context. This is something no amount of written words can transfer, because they do not come with perceived audio experience, which you must figure out yourself. At least, this is my opinion about the stuff, does it make sense?

And yes, ~constant highish directivity with proper toe-in seems to be one important thing for good sound to me, it makes the sound quite stable with the time intensity trading. By stable I mean the sound doesn't change (spectrally or spatially) too much with changing listening position, which makes it easy to listen to as it is not changing all the time with movement like in a worst case it could. As Duke said, phantom center stays pretty much at the center no matter where in room I'm listening, it doesn't collapse to nearest speaker like with no toe-in and no directivity. Another thing with smooth directivity is that listening axis can be anything always sounding good and now toe-in can be optimized for spatial effects of sound in main listening position, how the room sounds like beyond the "direct sound". Regarding which I think there is two perceptions of spatial sound just from our own auditory system, and in my experience toe-in supports the other (Griesinger stream separation) while no toe-in supports the other (no stream separation). These two are perceptually very different and basically need bit different optimization from room and speakers depending which one is preferred, ideally one would optimize for both.
 
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-Matt-

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Before discovering ASR I had several different models of B&W speakers. Most recommendations were to have them pointed to cross slightly infront of the MLP. I think the idea is to slightly reduce the high frequencies at the MLP because they have narrower dispersion than the lower frequencies.

Anyway, I've gotten used to seeing the speakers like that and so I definitely prefer (visually) to see a sliver of the outer sides of the speakers, rather than the inner sides. I now have Kef's with better directivity and on axis response, so I currently have them more or less pointing directly at the MLP.

Moving speakers around and attempting to get symmetrical positioning relative to the walls can be time consuming, so I've not recently tried experimenting with toe in. (Far easier to just fine tune the frequency response with EQ). Using toe in to itteratively optimise soundstage seems almost a fool's errand as the impressions are so subjective.

But this makes me wonder...
Could measurements be made with a stereo microphone system (simulating our ears) and some computer code (simulating our brain processing) in order to test the precision of sound object localisation? I'm imagining that you'd have test sounds with well defined locations in the soundstage and then the computer code would spit out position information (with uncertainty) for different sets of speakers (or for different toe-in etc).

I've not looked into the details, what are the capabilities of Trinov's fancy 3D microphone system?

Or maybe something like MiniDSP Ears but for speakers rather than headphones?
 
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sq225917

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Used to run a set of MA studio 2s like this long room, did a lot to tame the HF
 
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