Sonic benefits of conventional vs coaxial design?

[NTK]

As I recall, the OG LS50 did a pretty good job.

Here is a comparison of a 1 kHz square wave waveform with and without phase correction from the LS50 Wireless II white paper.

 

[voodooless]

Here is a comparison of a 1 kHz square wave waveform with and without phase correction from the LS50 Wireless II white paper.

View attachment 556289

Yes, I suspect that my own recoding was with Dirac enabled

 

[2020]

I just can’t wrap my mind around treating AI regurgitation of scrapped and plagiarized bits and fragments of scattered human statements, mindlessly processed and reconstituted into unsubstantiated confident expressions of insight and synthesizing knowledge and judgment, as authoritative and sensible.

Well that's why I prefaced it with AI context. It's logic reasonable to me, but if you see a mistake, feel free to correct it.

 

[Duke]

A few observations, probably none of this news to anyone:

1. Even at very close distances, a coaxial has no audible vertical discontinuity. At normal listening distances this advantage tends to fade as the ears don't have very good angular resolution in the vertical plane.

2. The vertical dispersion of a coaxial is way better than that of a conventional speaker, and is often just as good as the horizontal dispersion. I say "often" because there are coaxials whose high frequency sections narrow in the vertical plane, but they still generally have better vertical dispersion than a conventional speaker because there is no vertical offset to pinch the pattern in the crossover region.

3. Coaxials tend to have inherently good pattern-matching in the crossover region and tend to have somewhat narrower and considerably more uniform off-axis response than conventional speakers.

4. Imo large vibrations of the cone are detrimental to clarity because of their effect on the tweeter's output (clarity being primarily a high-frequency phenomenon). So imo a high-output coaxial should be at least a three-way to prevent large-amplitude excursions of the cone affecting the tweeter's output. There are coaxial units wherein the tweeter's output doesn't "see" the cone's motion, and those configurations introduce other trade-offs, but they are probably the better candidates for use in high-output two-way systems.

5. The cone of a coaxial is probably never going to be as ideal of a waveguide as a dedicated waveguide can be.

In my opinion good three-way coaxials offer a really attractive combination of attributes.

 

[ryanosaur]

There's been a long simmering conversation on a thread from a different forum where one user keeps asking the Designer to do a new Center using a small coaxial driver with some other small woofs in hopes of seeing a very inexpensive Center that is smaller than 6" high.



I appreciate that @Mort brought this up over here. I know I've been intrigued by a few Coaxial designs, recently.

 

[Flaesh]

three-way coaxials

KRAKATOA Quintuple 18" Point Source Full Range

... in the spirit of ASR fun, for those looking for an active full range speaker, a new one just released: https://www.bassboss.com/catalog/krakatoa-quintuple-18-powered-point-source 4-Way quintuple 18” powered co-axial point source full range Full-Range single axis point source. Vented...

www.audiosciencereview.com

 

[Duke]

KRAKATOA Quintuple 18" Point Source Full Range

... in the spirit of ASR fun, for those looking for an active full range speaker, a new one just released: https://www.bassboss.com/catalog/krakatoa-quintuple-18-powered-point-source 4-Way quintuple 18” powered co-axial point source full range Full-Range single axis point source. Vented...

www.audiosciencereview.com

View attachment 556332

Actually something like the @SigbergAudio Manta is what I had in mind, with the woofer being completely separate from the coaxial.

Here's a link to the spec sheet for what I believe to be the 18" triaxial driver in that image:

https://www.parts-express.com/pedocs/specs/294-6472--bc-speakers-18htx100-8-spec-sheet.pdf

Notice the woofer's +7 dB peak at 600 Hz, followed by a similar-sized dip at 900 Hz. This is largely from some of the cone's output bouncing off the back of the horn back to the cone and then bouncing off the cone, some of it to perhaps bounce off the back of the horn again. This would be the trade-off for having that nicely-behaving separate horn. And EQ cannot remove the bounce itself.

"Speaker design is tradeoffs, Highness. Anyone who says differently is in marketing." - from The Princess Bride, poetic license invoked.

 

[Putter]

I tried the Adam A8H, a conventional speaker that is marketed as both midfield and nearfield, with a different reasoning behind it.

The company considers it midfield because of it's power/projection potential (116db at 1m) and "conventional wisdom" says it's also midfield due to the 8" woofer that specs at -3db at 34hz. However, Adam also says it's nearfield because it's minimum listening distance is only 0.6m, which is quite small. So it is possible to go below the standard 1m.

I asked Gemini AI about this a while ago and it said in a perfect scenario, where there is no problems with room acoustics or placement, traditional design would win because it would be be perceived as larger and more powerful (dynamics). It also said that it was more "pure" because each driver does less and the benefits are maximized in the process (unlike coxial, where the midwoofer acts as a waveguide for the tweeter and then the tweeter is technically being modulated and this is distortion). It said coaxial's real benefit was imaging and ease of integration. Because it's naturally in phase and has point source properties, it's less likely to interact with the room in asymmetric or "ugly" ways. Also, it will likely have a larger sweet spot so it will be more forgiving or placement or the listener moving. It went on to say that traditional design's weakness are just real spaces, but with that taken out of the equation in our hypothetical, it doesn't really have any weaknesses. Coaxial then loses by default because it's meant to address something that's no longer a real issue (unless you are obsessed with phase and prioritize that first).

While I admit I'm a KEF fanboy, the AI response is not really helpful. First of all, it's just a big block of prose with no separation of thoughts. It also doesn't make a lot of sense. It says that conventional speakers win because their weakness is use in conventional rooms. Room response is considered to be one of the biggest problems in speaker response. Just listen to a speaker in bare room. The best imaging I have ever heard was on a pool deck with conventional speakers, i.e. no room response. We don't listen to speakers in hypothetical rooms with no reflections.

Of course the answer is that coaxials have advantages such as better imaging more uniform dispersion and disadvantages like increased intermodulation distortion and are typically more expensive to manufacture. Also Amir's tests have shown excellent speakers of both types.

 

[berjine]

All coaxials are not created equal though. I had 2 pairs of Tannoy for a few years (passive 10" and active 6") and basically there was no imaging whatsoever compared to good conventionnal 2-ways. Phantom center was very strong but that was it, everything was in the center !
The homogenous directivity was great though for casual listening, I had them at the 4 corners of the room, gave me good sound everywhere, sitting or standing.
I have to try modern ones they seem very good

 

[Flaesh]

to try modern ones they seem very good

Here's a not-so-new, but still relevant Tannoy model. One guy uses it at home, but I don't know him. As Duke likes — separate woofers, 2x12". And as I like — already done for separate subwoofers, not these huge boxes with holes.. But there are tradeoffs everywhere — for home use, subs a little lower are probably better.

Notice the woofer's +7 dB peak at 600 Hz, followed by a similar-sized dip at 900 Hz. This is largely from some of the cone's output bouncing off the back of the horn back to the cone and then bouncing off the cone, some of it to perhaps bounce off the back of the horn again. This would be the trade-off for having that nicely-behaving separate horn. And EQ cannot remove the bounce itself.

With steep crossover at 600 Hz it might not be so scary. And by the way, this was [somewhat!] humorous project for a compromise basless compact desktop speaker.

"Speaker design is tradeoffs

For example, subwoofers will need to be proportionate for Desktop18HTX100. And many may need a second table for stereo pair of Desktop18HTX100. Another this speaker name is TwentyTwentyTwelve in honor of box size (the horn sticks out forward a little)

 

[aarons915]

The measurements have been discussed and whether they actually matter or not but what I've found that drew to KEF speakers in the first place was that they sounded clearer and had a better point source presentation than a well designed typical 2 way speaker. It was my 1st blind comparison and it was between the LS50 and the Revel M105, I did a writeup at AVS forum and believe here as well but it was very surprising to me since I was expecting the M105 to win based on measurements.

This is something I never noticed until directly comparing the 2 level-matched, with a single speaker of each in mono and being able to instantly switch back and forth.

 

[Duke]

With steep crossover at 600 Hz it might not be so scary.

Yup, I think that's what would have to be done.

 

[Torin Krell]

My Genelec "The Ones" 8341A coaxial speakers have received excellent reviews and have far smoother ceiling and floor reflections than my conventional speakers. I find that their sound also remains significantly more consistent as I move around my music room, sitting / standing etc. With the balanced addition of my two 12" subs I have been very satisfied with this setup for over 5 years. They are my preferred sound system in my home over some other quality gear.

 

[dfuller]

The company considers it midfield because of it's power/projection potential (116db at 1m) and "conventional wisdom" says it's also midfield due to the 8" woofer that specs at -3db at 34hz.

The max SPL they provide is ridiculously optimistic, it's distortion limited to below 100dB/1m by their own measurements.

A true midfield costs easily 2x as much (KH350 or S360, or for the purposes of this thread 8361, for example) and is much larger. They also go much, much louder. Like, 10-20dB louder in the midrange easily, never mind the low end.

Anyway to stay on topic the big advantage of coax that I see is that minimum listening distance is reduced dramatically. 8361s still make sense within 1m - kh420s, for example... Not so much.

 

[Flaesh]

Oleg said that they say it's coaxial:

But that’s not certain—maybe it’s just a double phragm mid(?). The terminals on the gray part are visible.

 

[MattHooper]

Imaging depth seems to be better in my experience with coaxials. Even with coaxials that don't seem to have very wide dispersion, it feels like there's better row separation between instruments. I think the uniformity of the dispersion probably creates some interesting effects with the reflections that you don't get with traditional dome and cone speakers.

FWIW,

I use both Joseph Audio Perspective2 speakers and Thiel 2.7 speakers.

The Thiels are a first order/time aligned design using a coax mid tweeter. The Josephs are a high order crossover 2.5 design.

Both speakers in my room produce a tremendous sense of depth with precise imaging and layering.

I would say the Thiels sonic images feel a bit more dense and focused though .