Ellipticor

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poseidonsvoice

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Re: Ellipticor
« Reply #1 on: 12 Feb 2018, 10:48 am »
John,

Thanks for the post! So that is what Troels Gravesen looks like  :thumb: !

The drivers look interesting for sure, and the pricing doesn't seem out of line for what Scan-Speak charges. That will appease some of us who in the Pro-Audio and compression tweeter crowd. We value high efficiency amongst other things. That being said, the overall efficiency of that 2 way design will be about 92dB or less (limited by the mid woofer due to baffle step correction), so not terribly high imho but higher than what most people are used to. In fact, Troels' version (see link below) is about 90dB.

The tweeter does appear to be in a small (woefully small!) waveguide. I would like a much bigger and deeper one of course for better directivity control to lower frequencies, not just to a few kHz.

All that being said, I have had several of my colleagues build Troels' designs, only to sell them off within 6 months or so  :oops:  :scratch:  :?

Troels' website is beautiful. I think he enjoys woodworking as well. I suspect he enjoys publishing his designs (and promoting them) and woodworking just as much as if not more than actually doing the proper engineering needed for a well measuring loudspeaker. I have listened to 2 of his designs and well...they do some things well and not some others.  My $.02. He likes to do a lot of "voicing, listening, tweaking and re-tweaking."

Here is the Elipticor 2 way you referenced in the soundstage link above, with full details: http://www.troelsgravesen.dk/Ellipticor-1.htm

In the off axis response, you can see the dip that starts between 1-2Khz (which will only get deeper if you continued to measure all the way out to 90 degrees) as well as a loss in directivity control from 3-4.5Khz. Above 5khz looks nice, although we have less and less music up there  :wink: Constant directivity from at least a low 1khz all the up to 8khz would be ideal, but then again, very few speakers manage that. And those that do are all well...big!

Best,
Anand.

JLM

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Re: Ellipticor
« Reply #2 on: 12 Feb 2018, 11:26 am »
Thanks for the heads up John.  Finally drivers worthy of more expensive speakers.  It grinds me that speaker finishes can cost several times the price of drivers.  (The drivers in my floor standing single driver speakers cost 50% of the total speaker.)

JohnR

Re: Ellipticor
« Reply #3 on: 12 Feb 2018, 11:42 am »
The tweeter does appear to be in a small (woefully small!) waveguide. I would like a much bigger and deeper one of course for better directivity control to lower frequencies, not just to a few kHz.

I can't figure out the waveguide thing, in the photos of the tweeter alone there appears to be none, in the photos of the tweeter in the box at appears that there is one. For example:



vs



Perhaps there's some sort of adapter faceplate. Anyway, my "personal jury" is still out on the larger waveguides that you like, but I do have a project lined up for this year (I hope).

Yes, he definitely likes woodworking :) I did wonder about his comment about the "whopping" Qm (Qms?) of 6.5 - I just looked up a pro driver I was looking at recently (Faital Pro 12FH520) and it has a spec'ed Qms of 11.1. (I'm really not sure what difference it makes.)

poseidonsvoice

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Re: Ellipticor
« Reply #4 on: 12 Feb 2018, 11:56 am »
John,

They sure do look cool despite the claims!

Qms figures should be taken in the context of the size of the driver. Linear relationship pretty much. So compare it to other 7 inch drivers to be fair. Faital makes wonderful stuff...

I look at BL and BL squared/Re to get an idea of the “Force factor” of a driver which helps me discern subjective qualities like “impact, jump factor, etc...”

If Paul Spencer of Red Spade Audio is near you, give a listen to some of his designs...

Best,
Anand.

AJinFLA

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Re: Ellipticor
« Reply #5 on: 12 Feb 2018, 05:27 pm »
I can't figure out the waveguide thing, in the photos of the tweeter alone there appears to be none, in the photos of the tweeter in the box at appears that there is one. For example:


I think what used to be called a "recessed" dome with flat faceplate is now called a "waveguide" for marketing purposes. One can clearly see from the data there isn't much "guiding" going on.
Some really puzzling drivers from Scan. The tweeter looks almost obscene. Nothing new either, as Audax made an elliptical dome eons ago.
Sensitivities are decent, but both will require some filter parts to flatten response. The "directivity" control of the tweeter is at near useless frequencies. In fact, since the sound power will dive even more at HF, they could sound a bit "dark", with little air in some rooms. Kind of the opposite of a ribbon which typical exhibits that kind of vert/horz asymmetry.
Oh well, at least they have the pricetags to attract the bling crowd.  :wink:

poseidonsvoice

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Re: Ellipticor
« Reply #6 on: 12 Feb 2018, 05:47 pm »
I think what used to be called a "recessed" dome with flat faceplate is now called a "waveguide" for marketing purposes. One can clearly see from the data there isn't much "guiding" going on.
Some really puzzling drivers from Scan. The tweeter looks almost obscene. Nothing new either, as Audax made an elliptical dome eons ago.
Sensitivities are decent, but both will require some filter parts to flatten response. The "directivity" control of the tweeter is at near useless frequencies. In fact, since the sound power will dive even more at HF, they could sound a bit "dark", with little air in some rooms. Kind of the opposite of a ribbon which typical exhibits that kind of vert/horz asymmetry.
Oh well, at least they have the pricetags to attract the bling crowd.  :wink:

Couldn't have said it better myself AJ.   Hope you are doing well.

Best,
Anand.

neekomax

Re: Ellipticor
« Reply #7 on: 12 Feb 2018, 10:06 pm »
Constant directivity from at least a low 1khz all the up to 8khz would be ideal, but then again, very few speakers manage that. And those that do are all well...big!

Best,
Anand.

Don't many speakers using Uni-Q drivers and the like achieve something like constant directivity between 1 and 8khz? They're not all very big, or rare. Unless I'm missing something (fort possible, as the French say).

poseidonsvoice

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Re: Ellipticor
« Reply #8 on: 13 Feb 2018, 12:45 am »
Don't many speakers using Uni-Q drivers and the like achieve something like constant directivity between 1 and 8khz? They're not all very big, or rare. Unless I'm missing something (fort possible, as the French say).

I mispoke. I was specifically relating to waveguide designs. You can’t manage constant directivity down to a low frequency with a small waveguide. They get large real quick, like 12,15,18,24 inches, etc...

Coincident designs can exhibit constant directivity but their dispersion is much wider (ie, not as “controlled” as waveguides). It’s not right or wrong, it can affect how you treat your room. Getting coincident designs right is also difficult. KEF, ELAC, Soundfield Audio, TAD, etc...that is still a smaller group than the non constant directivity designs in the world of loudspeakers. I’ve seen measurements on the Spatial M4, and sadly left unimpressed. The M3’s most likely are similar.

Let’s put it this way Neeko. Just because a company “claims” constant directivity, doesn’t  mean they are. One should ask for the measurements to see the degree to which as well over what bandwidth they are constant.

And whether a design uses coincident design, waveguides, horn, dipole, etc...means nothing to me anymore. Only because I have seen dramatically different executions and competence in design. If I am a paying client I want the truth, because well, I deserve it!

Best,
Anand.

neekomax

Re: Ellipticor
« Reply #9 on: 13 Feb 2018, 01:38 am »
I mispoke. I was specifically relating to waveguide designs. You can’t manage constant directivity down to a low frequency with a small waveguide. They get large real quick, like 12,15,18,24 inches, etc...

I see what you mean. Like the SEOS 12" waveguide that I have with the Jeff Bagby Fusion Tempest 12 kit that I still haven't built.  :lol:

But that still is just for the compression drive tweeter, so not what you're talking about really, either.

neekomax

Re: Ellipticor
« Reply #10 on: 13 Feb 2018, 01:48 am »
I’ve seen measurements on the Spatial M4, and sadly left unimpressed. The M3’s most likely are similar.



Be interested in seeing what you're talking about here, in case you still have a link handy.

jtwrace

Re: Ellipticor
« Reply #11 on: 13 Feb 2018, 01:58 am »
I mispoke. I was specifically relating to waveguide designs. You can’t manage constant directivity down to a low frequency with a small waveguide. They get large real quick, like 12,15,18,24 inches, etc...

Coincident designs can exhibit constant directivity but their dispersion is much wider (ie, not as “controlled” as waveguides). It’s not right or wrong, it can affect how you treat your room. Getting coincident designs right is also difficult. KEF, ELAC, Soundfield Audio, TAD, etc...that is still a smaller group than the non constant directivity designs in the world of loudspeakers. I’ve seen measurements on the Spatial M4, and sadly left unimpressed. The M3’s most likely are similar.

Let’s put it this way Neeko. Just because a company “claims” constant directivity, doesn’t  mean they are. One should ask for the measurements to see the degree to which as well over what bandwidth they are constant.

And whether a design uses coincident design, waveguides, horn, dipole, etc...means nothing to me anymore. Only because I have seen dramatically different executions and competence in design. If I am a paying client I want the truth, because well, I deserve it!

Best,
Anand.
Sure hope my speakers meet your standards.   :P

JohnR

Re: Ellipticor
« Reply #12 on: 13 Feb 2018, 03:47 am »
Perhaps I should not have used the "W" word  :lol: This is a 1 inch dome tweeter... I was just trying to figure out why the photos with the tweeter in the box look different...

Perhaps another thread on small waveguides...