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

[salvasol]

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

[avaserfi]

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

[Sonnie]

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.

[avaserfi]

Sonnie wrote:

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.

Why I'll teach you to pick at me!

DS-21 wrote:

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.

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.

DS-21 wrote:

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 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.

DS-21 wrote:

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.

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.

[Sonnie]

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!

[avaserfi]

Sonnie wrote:

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

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.

Sonnie wrote:

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.

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.

Sonnie wrote:

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

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.

Sonnie wrote:

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

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.

[Sonnie]

avaserfi wrote:

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.

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.

avaserfi wrote:

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.

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.

[avaserfi]

Sonnie wrote:

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.

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.

Sonnie wrote:

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.

Then enjoy and don't worry about it .

[Sonnie]

DS-21 wrote:

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.

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!