KEF R3 Speaker Review

[QMuse]

Audioholics mentioned this in their latest video too.

I watched that video before but I don't remember that guy recommending extreme toe-in. Or..?

 

[Vuki]

In the 90s Audio Physics was recommending wide setup and extreme toe in. When done right it provides great imaging and wide soundstage. Absorber on the front wall between the speakers also helps.

 

[QMuse]

As far as I know, there's no direct research on this, so you have me there. That said, this shouldn't be about winning an argument. This is about logic. What do you honestly think. If you have very narrow dispersion speakers, then extreme toe in means that as you get further away from the left speaker, you become more on axis to the left speaker. Do you disagree with this?

I already agreed that extreme toe-in emphasizes direct sound and reduces reflections. Honestly, I tried it and it sounded awful.

 

[richard12511]

I own very narrow dispersion speakers. With no toe in, the sweet spot is about 2-3inches wide. With on axis toe in, it's maybe 8inches wide. With extreme toe in, it's 3ft wide.

 

[richard12511]

I already agreed that extreme toe-in emphasizes direct sound and reduces reflections. Honestly, I tried it and it sounded awful.

What speakers do you use?

 

[QMuse]

What speakers do you use?

Castle Harlech S2. And manufacturer recommends the same thing as Kef - little or no toe-in.

 

[richard12511]

With my narrow dispersion speakers (JTR), and extreme toe in, I'd say the sound quality gets about 5-10% worse, but the sweet spot doubles(or triples) in width, so the trade off is worth it.

 

[QMuse]

I own very narrow dispersion speakers. With no toe in, the sweet spot is about 2-3inches wide. With on axis toe in, it's maybe 8inches wide. With extreme toe in, it's 3ft wide.

Which speakers do you have? What is the distance between your LP and them?

It would be easier to talk about this if you can post measurements done from your LP for all these 3 scenarios.

 

[napilopez]

"Just the response you have in writing"? That seems uite official and valid to me.



Sure they do. And why wouldn't they? Or you think Dolby engineers got it wrong?

Okay, I think we're getting a bit confused now. I'm not disagreeing with KEF engineers.

Let me clarify the points I'm trying to make:

• In most cases, the KEF R3 sounds best with no toe in. This will also give you the largest soundstage in most cases.
• It will have the widest sweet spot with extreme toe in. This does not mean it will have the best sound or widest soundstage with extreme toe in. It can help with spatial presentation on a case by case basis, and will usually mean a more diffuse image, but not necessarily a wider one. But the fact that it will increase the width of the sweet spot is a pretty different matter.
• To be clear, bigger sweet spot width does not necessarily mean a larger soundstage. It means that you do not need to be sitting exactly in the center between two speakers to get a stable stereo image.
• The 5.1 positioning recommendations are not the same as 2.0 positioning recommendations. Fewer sidewall reflections are more acceptable/arguably better in multichannel setups.

So it can be true that the R3 sounds best with no toe in and that it will have the largest sweet spot with extreme toe in.

Do you care to provide some proof for that "fact"?

I know what Geddes says, I read his directivity paper about that, but I would prefer some measurements instead of his opinion.

I guess both richard and I assumed this was pretty common knowledge around these parts, extreme toe in as it relates to time-intensity trading. It is not trivial to measure as it is a psycho-acoustic effect. Check this whitepaper by Bill Waslo. More technical info in this AES paper.

 

[Vuki]

Wide placement extreme toe in AES paper

 

[richard12511]

Which speakers do you have? What is the distance between your LP and them?

It would be easier to talk about this if you can post measurements done from your LP for all these 3 scenarios.

I don't think I've taken measurements with those 3 scenarios, but I agree that I should. Maybe I'l do that this weekend.

I've got 5 different pairs of speakers (JTR 210, Revel M105, JBL 308p, JBL 305p, Infinity Beta 20), but the JTRs are my mains. I think the JTRs sound best on axis, but extreme toe in isn't that much worse, and it doubles or triples the sweet spot width.

It's less notable with the Revels or JBLs. I think this is due to their wider dispersion. I listen to them on axis.

 

[Erik]

I know what Geddes says, I read his directivity paper about that, but I would prefer some measurements instead of his opinion.

They are in the presentation I linked
He even made a program that simulates the sweet spot width depending on the loudspeakers characteristics and their toe-in.
http://www.gedlee.com/Application Files/RunRoomResp.aspx
Does not work on my PC, though.

 

[Zvu]

Gentlemen, please read this whitepaper before you continue arguing about this:

http://libinst.com/PublicArticles/Setup of WG Speakers.pdf

 

[QMuse]

So it can be true that the R3 sounds best with no toe in and that it will have the largest sweet spot with extreme toe in.

I suggest you ask KEF to check that theory. I would be really interested to hear what will they answer.

Btw, I find it interesting that Dolby guys are not using that trick as with AV setups you do need a wide sweetspot.

 

[Jon AA]

I suggest you ask KEF to check that theory. I would be really interested to hear what will they answer.

Did you completely miss all the conversation we had about this earlier in the thread? This is not some new half-baked theory somebody on this board came up with. Can you not look at horizontal off-axis measurements of relatively narrow, relatively constant directivity speakers, do a little geometry and figure out for yourself there might be something to it? Or better yet, try it with some appropriate speakers (though I haven't seen measurements for your speakers, from their design it's doubtful they'd be good candidates)?

 

[napilopez]

I suggest you ask KEF to check that theory. I would be really interested to hear what will they answer.

Btw, I find it interesting that Dolby guys are not using that trick as with AV setups you do need a wide sweetspot.

Not going to bother them just for what I consider to be common and factual knowledge, but if I remember I'll bring it up next time I review one of their speakers. I have already tested this with the R3s and about a dozen other speakers -- essentially every time I test a speaker with a substantial waveguide.

In any case, there are about 5 different papers/resources above you can read through . It's very easy to test yourself with narrower directivtiy/Constant directivity designs. Try no toe in, then try extreme toe in, and sit a foot to left or right of your sweet spot. See which one has the more stable stereo image then.

Dolby can't universally recommend it because it only works with some types of speakers, and there's no point to it if you have a center speaker.

In any case, it's not clear the dolby image actually implies anything about toe in. The angles presented in the graphic may be about the speaker's spatial location in your room, not how much they should be toed in. And obviously, not every speaker on the market should be toed in the same, but positioning does matter in the way sounds are mixed for dolby standards.

 

[QMuse]

Not going to bother them just for what I consider to be common and factual knowledge, but if I remember I'll bring it up next time I review one of their speakers. I have already tested this with the R3s and about a dozen other speakers -- essentially every time I test a speaker with a substantial waveguide.

In any case, there are about 5 different papers/resources above you can read through . It's very easy to test yourself with narrower directivtiy/Constant directivity designs. Try no toe in, then try extreme toe in, and sit a foot to left or right of your sweet spot. See which one has the more stable stereo image then.

Dolby can't universally recommend it because it only works with some types of speakers, and there's no point to it if you have a center speaker.

In any case, it's not clear the dolby image actually implies anything about toe in. The angles presented in the graphic may be about the speaker's spatial location in your room, not how much they should be toed in. And obviously, not every speaker on the market should be toed in the same, but positioning does matter in the way sounds are mixed for dolby standards.

So you would recommend to all owners of say Revel F208 to apply extreme toe-in to their speakers so they are crossed several feets before them?
Is that how you listen to your speakers?

Btw, I just looked at a photos of Toole's and @amirm room and that is not how their speakers are positioned. Have they no clue how it should be or their speakers are not directional enough?

 

[Jon AA]

So you would recommend to all owners of say Revel F208 to apply extreme toe-in to their speakers so they are crossed several feets before them?
Is that how you listen to your speakers?

You're really missing the point.
1) The F208s are extremely wide dispersion through the upper mid-lower treble region. It's unlikely to work well, if at all with them.
2) Like anything else about setup, everything is a compromise. Even with speakers for which this works well, it's largely useless for a 2-channel listening room where all you care about is a single sweetspot. For that one would play with toe until they sound the best for that spot.

The whole point behind it is widening the sweetspot so it sounds better when you're not perfectly centered between the speakers. This is extremely useful for giving the best experience to multiple listeners or for any listener who doesn't want to sit in the exact same location all the time.

 

[tuga]

You claimed that extreme toe-in widens the sweet spot. As KEF engineers don't recommend any toe-in, or in some special cases only moderate, you must know something they don't.

Where did you get that information?
These are from the Kef manuals:

 

[napilopez]

So you would recommend to all owners of say Revel F208 to apply extreme toe-in to their speakers so they are crossed several feets before them?
Is that how you listen to your speakers?

Btw, I just looked at a photos of Toole's and @amirm room and that is not how their speakers are positioned. Have they no clue how it should be or their speakers are not directional enough?

You hit the nail on the head. They are not nearly directional enough.