Arendal 1723c 2way mtm has 45° horizontal dispersion?? Lies?

[GabrielPhoto]

Hi.
A guys is claiming that this link proves the 1723 center has 45 degrees of horizontal dispersion....

1723 Center THX

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arendalsound.com

Unless it was designed at Hogwarts, I don't see how that is happening with a 2-way horizontal MTM center.
Am I missing something?

 

[moonlight rainbow dream]

+/- 22 degrees is not a lot. In a horizontal MTM, if you push down the crossover frequency and woofer centre-to-centre distance enough, you can achieve figures like that.

 

[GabrielPhoto]

+/- 22 degrees is not a lot. In a horizontal MTM, if you push down the crossover frequency and woofer centre-to-centre distance enough, you can achieve figures like that.

I mean the person is claiming 45º each side of MLP for a 90º total!

 

[Beave]

I saw the post and was about to comment. Those measurements are likely for the speaker stood upright (ie, vertically, ie, woofer over tweeter over woofer, ie upright MTM). I don't see how a 2-way toppled MTM could have those measurements otherwise.

 

[GabrielPhoto]

I saw the post and was about to comment. Those measurements are likely for the speaker stood upright (ie, vertically, ie, woofer over tweeter over woofer, ie upright MTM). I don't see how a 2-way toppled MTM could have those measurements otherwise.

Now that you mention that I kind of recall someone saying that Arendal was been very misleading with that and that it was measured vertically.
But yeah if they can do 45 degrees left and right with a way mtm they just have found some magical configuration nobody else has lol

 

[muad]

I saw the post and was about to comment. Those measurements are likely for the speaker stood upright (ie, vertically, ie, woofer over tweeter over woofer, ie upright MTM). I don't see how a 2-way toppled MTM could have those measurements otherwise.

For sure, there's no lobing in the polar plot.

 

[moonlight rainbow dream]

Well I went and dug this up. Horizontal off-axis plot for the Encore C6 by Erin... similar layout speaker, but with 6.5" woofers.

 

[GabrielPhoto]

Well I went and dug this up. Horizontal off-axis plot for the Encore C6 by Erin... similar layout speaker, but with 6.5" woofers.

Sadly I can't picture things without the polar map or countur thing lol

 

[Sancus]

https://www.audioholics.com/bookshelf-speaker-reviews/arendal-1723/conclusion/1723verticalwaterfallresponse.jpg/image

The above is the same design as a bookshelf, so that would be its horizontal response when placed horizontally. So, no, it's just a normal 2way center. Also don't believe everything you read on a manufacturer's website.

 

[GabrielPhoto]

Ok no more mystery..I got a reply from Arendal


Thank you for reaching out and for your interest in our speakers.
Unfortunately, we do not have the horizontal measurements of the 1723 Center.
But Audioholics did a review of the 1723 Monitor, which is the same speaker as the Center, and measured the horizontal and vertical orientation.
Please have a look here.

Do not hesitate to contact us with any additional questions

They link to the same audioholics review I took the graph from before so there you have it... Nothing magical from their mtm..This is the horizonal dispersion
View attachment 3363729

 

[fpitas]

You can get even a horizontal MTM to have wide horizontal dispersion, if you use an odd--order Butterworth crossover like D'Appolito did, specifically BW3 for his original MTM.

 

[617]

You can get even a horizontal MTM to have wide horizontal dispersion, if you use an odd--order Butterworth crossover like D'Appolito did, specifically BW3 for his original MTM.

How does that work? A 20" wide woofer array is still far more directional than a dome tweeter.

 

[fpitas]

How does that work? A 20" wide woofer array is still far more directional than a dome tweeter.

The woofers are in quadrature with the tweeter, which spreads the beam. It's wavy, but try it yourself in XDir for example.

Tolvan Data

 

[617]

The woofers are in quadrature with the tweeter, which spreads the beam. It's wavy, but try it yourself in XDir for example.

Oh, clever. So they're 1/4 out of phase?

 

[fpitas]

Oh, clever. So they're 1/4 out of phase?

Yes, 90 degrees, like Butterworth has to be for flat on-axis.

Soon afterwards D'Appolito decided that LR4 sounds better for MTM. And here we are...

 

[617]

Yes, 90 degrees, like Butterworth has to be for flat on-axis.

Soon afterwards D'Appolito decided that LR4 sounds better for MTM. And here we are...

Yes I remember the MTM crossover wars of...whenever that was. 2011? Remember when everyone was designing MTMs with dayton RS180s and an RS28f or a?

Then Jeff Bagby contributes with this:

6 components. Good times.

 

[fpitas]

Yes I remember the MTM crossover wars of...whenever that was. 2011? Remember when everyone was designing MTMs with dayton RS180s and an RS28f or a?

Then Jeff Bagby contributes with this:

6 components. Good times.

Jeff was the undisputed master of simple but effective crossovers.

 

[GabrielPhoto]

So if this is a good option to get better dispersion from horizontal MTM, why it seems nobody uses it and just design crippled 2way mtm centers?

 

[fpitas]

So if this is a good option to get better dispersion from horizontal MTM, why it seems nobody uses it and just design crippled 2way mtm centers?

Not sure what this does or doesn't do. By the few graphs I've seen here, it uses even-order in-phase crossovers, so it has a narrowed beamwidth. As for people using 3rd order BW, several DIY designs for horizontal MTM I've seen do. It always surprises me how f*cked up crossovers on commercial speakers are. Maybe they have no one that knows about electronics? Caveat emptor...

 

[617]

Back to the subject at hand. The Arendal measurements slyly omit whether the measurements are horizontal or vertical. For some reason, in the off axis chart they provide, they emphasize that the off axis sound sums to something called the power response, which is not a very useful graph to provide, not that they provide it.

I don't see where they claim 45 deg of dispersion, and such a figure would have to be accompanied by some kind of tolerance (+/- 6db or whatever) to be meaningful. This speaker, like any speaker, will produce some sound at every frequency at every angle, the question is how much.

The deep waveguide probably helps this speaker but there's a reason high end center channels use coaxials or 3 way designs.