Horn tweeters V.S. aluminum dome tweeters

Which tweeter provides the bigger sweet spot, the horn tweeter or an aluminum dome tweeter?

My local high-end theater equipment store just told me on the phone that horn tweeters have a very narrow listening area, while dome tweeters have a much wider sweet spot. In contrast, I found a few internet articles that say just the opposite . . .

I'm forced to have far from ideal room conditions for my theater set-up (stuck in a corner, but rotated about 30 degrees), so I was wondering which tweeter would provide me with the wider sweet spot, enabling me to accompany more guest seating positions?

Thanks for any help anyone can provide.

Bob

Don't believe everything they say ... Do as you did, a research online to find out the differences

If you can, ask them if you can try them at home (What better way to decide which one are best for you ) ... if they can't loan you a pair, I'm sure they have a 30 day return/exchange policy ... you can buy a pair and excahnge/return if you don't like them

I believe I answered your question sufficiently here: http://forums.audioholics.com/forums...ad.php?t=40482

Yep... I think Andrew gets the bone on this one. Excellent answer, although I have no idea if he's telling the truth, but it sounds really good. Just picking at you Andrew.

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Sonnie



Cedar Creek Cinema

The Behemoth

Can't say I like that answer much.

A few things. First, all tweeters are "horn" tweeters, in the sense that all of them are loaded on a waveguide of some sort. (A flush baffle is just a 180deg waveguide.) Some of them are designed to improve power response (and thus imaging) by providing constant directivity over a given area, with a smooth rolloff of treble energy past that point. (Many coaxes, such as the KEF Uni-Q and Tannoy Dual Concentric, attempt constant directivity by using the cone profile as a CD waveguide.) Others (e.g. the Tractix flare used by Klipsch and others) does not attempt constant directivity. A 180deg waveguide is basically hopeless, and leads to all kinds of problems in the midband power response, because it does not control the dispersion of the tweeter at the bottom of its passband at all.

So generally, I think it's safe to say that the best imaging - especially the best imaging over a zone in a room, as opposed to a spot. - comes from constant directivity waveguides, with other waveguides being various levels of inferior to a good CD waveguide.

While technically you are correct every tweeter is a "horn" this is not the common terminology most are familiar with and I was answering with respect to the OPs terminology.

I am not sure if I understand your thought process here. With proper integration of drivers (the midrange and the tweeter) this is not an issue at all. *Clarification* What I mean by this is: With the proper crossover settings along side a midrange and tweeter with similar on and off axis responses this issue can be overcome. I am fully aware of this issue due to my current testing in which I am doing exactly this. With a mock baffle set up I have encountered no such issues.

In terms of the loudspeaker itself it is off-axis response that creates imaging and the sense of a sweet spot. Simple physics dictates that for the largest sweet spot greater off-axis dispersion is required and for this to be pleasurable this response need to mimic the axial response.

Of course the room plays a hugely important role in this situation, but again the OP asked about which type of tweeter which is why my emphasis lay on the loudspeaker not the room.

As far as waveguide versus off-axis dispersion they are two different but interrelated things. A waveguide does exactly what the name implies where the horizontal and in this case less importantly vertical response are "guided." While this can limit a tweeter's off-axis dispersion characteristics it does not entirely control the linearity of these responses which is why this distinction is important. Waveguides can control actual dispersion, but the dispersion itself dictates imaging so I guess in a sense both the waveguide and the tweeters resulting dispersion characteristics will be indicative of imaging/sweet spot sensation. If one is looking for a way to quantify this data off-axis response will be the most important data to collect and analyze.

Clear this up for me... I don't want to misunderstand what I'm reading.

Does this make any speaker other than the Klipsch, KEF Uni-Q and Tannoy DC or similar type horn useless?

I guess all these speakers developers for about 95% of the speakers on the market are not so smart... and the hundreds of speaker reviewers giving good marks to all these speakers with flush baffle speakers just don't realize all the problems that exist in these speakers and really shouldn't be writing reviews?

I wonder how all these speakers companies with flush baffles stay in business with all the problems that exist in this design?

I wonder where my Martin Logan's fit into all this?

And that monkey is just too funny!

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Sonnie



Cedar Creek Cinema

The Behemoth

Not at all. As I am sure you know no loudspeaker is perfect. This is why subjectivity comes to play so greatly when one goes out speaker shopping and listening you are narrowing down choices you are actually removing imperfections that you are more sensitive too.

Also, in some rooms it is preferable to have poor off-axis response. While in a technical sense this is not ideal there are certain situations such as an extremely reverberant room where off axis response would likely need to be tamed for maximum sound quality.

One extremely important thing to realize with speaker reviews is that the room they are auditioned in plays a paramount role in sound quality. So the reviewer is reviewing the specific loudspeakers interaction with the given room.

I don't know where you got this from, but flush baffles are used very often without problem. Internal to the tweeter (and thus in an area we cannot see or sometimes it just isn't noticed) there can be a waveguide which allows for proper dispersion characteristics without need for baffle compensation allowing for a flush mount with no problems.

If DS-21's reference to a 180 degree waveguide is where this came from I believe he was referring to a situation where a non-waveguided tweeter is used in conjunction with a flat baffle which is exactly what I plan on doing and as I have previously said is an extremely good idea if proper methodology is taken .

Baffle compensation is only really needed in the case where a non-waveguided tweeter is used and the tweeter in question has extremely linear off-axis response. If the compensation is not taken off-axis response will be ruined due to wave diffraction issues.

I am not aware of any credible 3rd party measurements on the Ascent I's. If you know of any I could give you my thoughts on the objective performance of the loudspeaker. If you wish not to jack this thread feel free to PM me or start another thread.

Yes... I was referring to his comments... (A flush baffle is just a 180deg waveguide.) and A 180deg waveguide is basically hopeless, and leads to all kinds of problems in the midband power response, because it does not control the dispersion of the tweeter at the bottom of its passband at all.


I am not aware of any either. I really haven't even studied the ML philosophy for that matter. I just can't get over how much I like the sound... even if someone discovers they are design flawed. In that case I would say I am glad they erred.

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Sonnie



Cedar Creek Cinema

The Behemoth

Yeah, I am pretty sure he was referring to a non-waveguided tweeter with a flat baffle. But I have already discussed why I disagree with this idea and why I even plan on using exactly what he said as hopeless in my current speaker design a couple posts back. Proper integration is key. Ambient field effects will change, but these can all be dealt with using proper planning and design.

Then enjoy and don't worry about it .

I've never heard a system with a flush-mounted tweeter that had a consistent sound on- and off- axis. All of them seem to get in trouble at the crossover region. Sure, there are some band-aids (e.g. the BBC dip) but to my ears they don't work as well as just doing it right to begin with.

Well, as a guy who's bought basically nothing but KEF or Tannoy speakers (with a short digression into a DIY MTM using Peerless HDS 8" woofers with various dome and planar tweeters) for the last decade (after comparing them with others before purchase) I would be inclined to say "yes." But that's just me.
(Not that I have much love for the Tannoys or KEFs that employ supertweeters. They seem to have the same problems, just higher up. I'd rather have some issues in the 10-20kHz octave than interference issues in the 5-10kHz octave. KEF seems to have moved away from the supertweeter approach. Hopefully Tannoy will soon, too.)

Furthermore, I would toss the Klipsch (Tractix flares are not CD, though they're better than 180deg waveguides), and add good CD waveguide implementations, e.g. the Danley Unity/Synergy horn, GedLee's OS flare, a lot of the current Toole-designed/inspired Harman stuff, SP Tech's speakers, some new Jamo models, most modern pro audio speakers, and so on. Not to mention other coax-based designs, such as the Gradients, TADs, Pioneer Elites, Danley Sound Labs, etc. Also, single-driver wideband speakers (point or line source) don't exactly have CD, but they also generally avoid the upper-mid "flare-out" in the power response endemic to the flush-mounted tweeter. Ditto for tall panels such as Sound Labs, Eminent Techs, ML's, and Maggies.

The other approach that might make some sense in some rooms is omnidirectional response. (Or as close to it as possible.) I can't say I've ever heard an omni system that wowed me, but in the right room (really, really dead) an omni speaker might be just the ticket, because that consistency of power response should in theory make for very even room response. That said, I've not heard the Duevel speakers, which are supposed to be pretty spectacular.

Also, another way to get around these problems might be to push the tweeter crossover way low, such that the directivity of the midwoofer at the top of its passband and the directivity of the tweeter at the bottom of its are still pretty close. (That's the Jon Marsh philosophy, more or less.) I don't know, not having tried it myself. Those Cauer-Ellptical crossovers at HTGuide.com are a bit intimidating for me.

Honestly, that sounds about right to me.

Note that when Toole started employing his blind testing methodology at Harman, good designs (waveguide-loaded tweeters, multiway centers) proliferated and bad designs (flush-mounted tweeters, toppled MTM centers) disappeared from all but the cheapest models, with the end result being that Harman has what I consider the deepest and broadest bench of good speakers right now bar none. Why? One obvious conclusion is that good designs implemented well sound better than bad designs implemented well.

See supra.

So the upper end of JBL, Infinity, Revel are all some of the better designs? Actually all of Revels centers appear to be the toppled MTM design. Seems to be the same with JBL and Infinity. I'm assuming Harman owns more speakers companies I'm not aware of and maybe I'm not looking at the right models. Can you be more specific? Thanks!

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Sonnie



Cedar Creek Cinema

The Behemoth

I think so, yes. At least, the ones that I've heard. Though I wouldn't just say at the upper end. An awful lot of their "mainstream" product is outstanding, too. Not outstanding enough to give up the Tannoy 12 DMTs for, but for someone who doesn't want a giant ugly bookshelf with a 12" coax, those three firms are a great place to start looking.
(I'm also sure Harman owns other speaker companies, but I don't know of them.)

Note also that other speaker companies known for prioritizing engineering over propaganda, such as PSB and Paradigm, are moving over to waveguide-loaded tweeters.

And the Revel centers aren't toppled-MTMs, unless they have a supercheap model of which I'm unaware. All of them from the Concerta up use a conventional MT with waveguide-loaded tweet flanked by two woofers. The crossover between the woofers and mids is low enough that the fatal flaws endemic to the 2-way toppled-MTM do not present themselves.

I plan to get a pair of bookshelf speakers with a center for our great room, so this thread may help me decide what to get. I had looked at the Klipsch and the JBLs... particularly the RB-51 and L830.




Bob... if this discussion is not helping you and you feel I'm hi-jacking your thread, let me know and we'll move it. I'm hoping that it's helpful to you though... and others as well.

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Sonnie



Cedar Creek Cinema

The Behemoth