Worst measuring loudspeaker?

[Justin Ayers]

Given the tweeter array thing, I wasn't terribly surprised to see that it measured fairly well on axis. I was surprised to see that it did well off axis too, though. I don't understand the tweeter array thing fully, but to its credit, it seems to work fairly well.

I assume that the tweeter array is used to improve dispersion. Having multiple tweeters that are at different angles should help to overcome the beaming problem. That's my assumption, at least.

Before I saw this Tekton just now, I was musing about a way to make the Fostex 31.5" FW800N woofer into an interesting speaker set and thought about having it in the center of a round speaker with the upper mid drivers and tweeter drivers in a circle around it. The tweeters would be aimed at slightly different directions to reduce "head in vise" beaming. I'm no speaker designer but I thought that might help to reduce the issue of directionality. It seems the Tekton takes a similar approach by making that circle of many tweeter drivers. One of my versions was just the woofer and the tweeter circle around it but I assume some high mids are needed with that woofer to improve its performance. Perhaps another option would be to have a planar midrange, possibly adjacent on its own stand, to avoid the less aesthetic look of mixing mid and tweeter drivers in the surrounding circle.

 

[andreasmaaan]

The tweeters would be aimed at slightly different directions to reduce "head in vise" beaming. I'm no speaker designer but I thought that might help to reduce the issue of directionality.

I'm afraid this won't help much with beaming, which is caused by interference between sound waves of the same frequency that travel different distances to the listener (e.g. from multiple tweeters). Since varying the direction in which the tweeters point doesn't significantly alter the relative path lengths from each tweeter to any given off-axis location, it won't do much to prevent beaming.

 

[Justin Ayers]

I'm afraid this won't help much with beaming, which is caused by interference between sound waves of the same frequency that travel different distances to the listener (e.g. from multiple tweeters). Since varying the direction in which the tweeters point doesn't significantly alter the relative path lengths from each tweeter to any given off-axis location, it won't do much to prevent beaming.

So is the only benefit to having so many tweeters to get away with using higher-efficiency tweeters that don't have the shortcomings of those designed to push more SPLs on their own? That was another thing I thought the circle idea might be able to accomplish. Weaker tweeters with higher efficiency (due to less mass) could supplement one another in terms of overall power level. Anyway... it's all speculation based on what little I know. Thanks for the clarification about the beaming. It figures that if the problem could be solved that easily most every model would have the multiple tweeters already.

Also, maybe I'm reading too fast but it seems that your comment suggests having multiple tweeters would increase the beaming problem, due to "interference between sound waves of the same frequency that travel different distances to the listener — e.g. from multiple tweeters".

 

[andreasmaaan]

So is the only benefit to having so many tweeters to get away with using higher-efficiency tweeters that don't have the shortcomings of those designed to push more SPLs on their own? That was another thing I thought the circle idea might be able to accomplish. Weaker tweeters with higher efficiency (due to less mass) could supplement one another in terms of overall power level.

That's right. One major benefit would be less stress on each tweeter, and therefore lower distortion, higher max. SPL, and/or the possibility of a lower crossover point.

Also, maybe I'm reading too fast but it seems that your comment suggests having multiple tweeters would increase the beaming problem, due to "interference between sound waves of the same frequency that travel different distances to the listener — e.g. from multiple tweeters".

In general, this is correct, although multiple tweeters can be used to control directivity in a way that may be desirable in a particular design. Certainly, one of the goals of the Tekton speaker is controlled vertical directivity. This is achieved to some extent, albeit in a chaotic fashion:

A better result could be obtained with multiple tweeters and progressive delays (either resulting from a curved or stepped baffle, or implemented electronically) and some form of intensity shading (i.e. such that different tweeters in the array produce differing SPLs for a given input voltage). Even then, the distances between the tweeters need to be very short for the off-axis behaviour of the array to stay controlled up to the highest audible frequencies (in general, no greater than one wavelength, which would be about 2/3" for an array that controls directivity to 20kHz).

Such large, intensity-shaded tweeter arrays are seen often in PA sound systems, and occasionally also in home audio systems (e.g. Don Keele's CBT speaker).

Unless you were very experienced or were following someone else's design, though, this kind of thing would make a very difficult project for a DIYer

 

[ahofer]

.but Ultralinear Speakers were a national brand that flourished for a few years using this economic model. They were sold exclusively by a single dealer in each market area and most of the material cost seemed to go towards large but very thin woodgrain cabinets, and aluminum speaker trim rings.

Just saw this. Yes, during my short and troubled time gophering at Atlantis Sound in 1978 they sold those. The salesmen joked about it all the time. Reminded me of this-

 

[Juhazi]

A candidate from Canada, 15.000/pair https://www.stereophile.com/content/acora-srb-loudspeaker

 

[thewas]

A candidate from Canada, 15.000/pair https://www.stereophile.com/content/acora-srb-loudspeaker

At least the drivers and horizontal and vertical directivity are decent so with some EQ it will probably sound good.
The price and bass reflex port are a bad joke though...

 

[andreasmaaan]

A candidate from Canada, 15.000/pair https://www.stereophile.com/content/acora-srb-loudspeaker

Like this and this, it's another batman speaker.

 

[Ilkless]

A candidate from Canada, 15.000/pair https://www.stereophile.com/content/acora-srb-loudspeaker

Impressive to coax so little from so much (Scanspeak Illuminator). Seems a combination of no BSC, underdamped bass alignment, maybe port resonance and the native response of the Scanspeak left uncorrected.

 

[Mnyb]

Anyone measured any of these white van speakers that where sld from parking lots

 

[andreasmaaan]

Impressive to coax so little from so much (Scanspeak Illuminator). Seems a combination of no BSC, underdamped bass alignment, maybe port resonance and the native response of the Scanspeak left uncorrected.

Whenever you see a Scan Iluminator or a Seas Mg Excel on a bookshelf speaker from a small, boutique manufacturer, 9 times out of 10, the best thing to do is run.

 

[Ilkless]

Whenever you see a Scan Iluminator or a Seas Mg Excel on a bookshelf speaker from a small, boutique manufacturer, 9 times out of 10, the best thing to do is run.

I can attest to that. Mag Excels have great midbass performance, but quite finicky with the notch and high-order slopes needed. Illuminators a bit more versatile, but something about it attracts really wonky boutique designs too...

The local SEAS distributor does (did?) custom builds. He was big on running the mag Excels 6dB/octave because lower part count XOs were "purer" and "less distorted"...

 

[andreasmaaan]

The local SEAS distributor does (did?) custom builds. He was big on running the mag Excels 6dB/octave because lower part count XOs were "purer" and "less distorted"...

Lol, exactly. Add a delicate, exotic tweeter that shouldn't be pushed below 3kHz, give it a 6dB roll-off beginning at 2.5kHz, and you've got the trifecta: a misguided concept, the wrong drivers for it, and terrible execution.

 

[Adam_M]

Whenever you see a Scan Iluminator or a Seas Mg Excel on a bookshelf speaker from a small, boutique manufacturer, 9 times out of 10, the best thing to do is run.

I'm not sure I completely agree with this. I haven't worked with any of the Illuminators, but the Excels can be tamed (depending on the situation, of course) with a 4-component XO to give a 4th order acoustic rolloff and the breakup completely eliminated (i.e. - smooth 4th order rolloff). Reputable boutique manufacturers won't have any issues.

Of course the ones referenced that use a first order slope - run away. Far away.

 

[andreasmaaan]

I'm not sure I completely agree with this. I haven't worked with any of the Illuminators, but the Excels can be tamed (depending on the situation, of course) with a 4-component XO to give a 4th order acoustic rolloff and the breakup completely eliminated (i.e. - smooth 4th order rolloff). Reputable boutique manufacturers won't have any issues.

Of course the ones referenced that use a first order slope - run away. Far away.

Absolutely. It can be done competently. It's just more common with a certain type of manufacturer IME that it isn't.

Really though, my comment was meant mostly in jest

 

[Purité Audio]

Perhaps not the worst but Wilson’s, ‘Sabrina X’ courtesy of Hi-fi News,


https://www.hifinews.com/content/wilson-audio-sabrinax-loudspeaker-lab-report

Keith

 

[Dialectic]

Perhaps not the worst but Wilson’s, ‘Sabrina X’ courtesy of Hi-fi News,


https://www.hifinews.com/content/wilson-audio-sabrinax-loudspeaker-lab-report

Keith

Over £20,000... Unbelievable.

 

[Purité Audio]

Come the revolution...
Keith

 

[sergeauckland]

Perhaps not the worst but Wilson’s, ‘Sabrina X’ courtesy of Hi-fi News,


https://www.hifinews.com/content/wilson-audio-sabrinax-loudspeaker-lab-report

Keith

And on top of lousy performance comes this:-
Positioning is excruciatingly critical. I know: every speaker ever made has optimal siting, so that's a truism, but the SabrinaX responds to every millimetre of change.

To me, the mark of a well engineered product is one that's 'fit and forget' or as near as. Anything too fussy, whether amplifiers that actually need special high inductance / low capacitance cables for stability, cartridges that need VTFs measured to the milligram or DACs that have no buffers or reclocking and need an ultra-low jitter input are just rubbish. What's worse is when a manufacturer actually makes a feature of being fussy (i.e. poorly engineered!)

Ditto loudspeakers, especially expensive loudspeakers. If they make a point of millimetre positioning, then they'll have serious problems with normal rooms.

S.

 

[Valhalla]

That sums it all up right there

Greg Roberts is basically a good carpenter. I would say he is a poet with wood. But he has little understanding of acoustic and electroacoustic and speakers IMO. His first model Vittora was a La Scala klipsch with rounded corners and upgraded parts. Parts that were popular back then in Klipsch community. Better Tractrix midrange horn (Edgar style) than the K400 exponential horn of Klipsch itself. Better compression driver (BMS 4592-mid) and better tweeters (Beyma CP25 at first and Faital Pro HF10AK afterwards). Faital Pro 15PR400 woofers. The bassbin of Vittora was designed by Mark Kravechenko. Crossover was designed by John Warren who is highly skilled in this. It seems that Greg is using less help from others in his recent models so no wonder about bad measurements. I still think Vittora could potentially sound very good taking the quality X-over and drivers used into consideration but I have no idea about Alura and Rival and Razz.