Waveguide opinions?

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soarertoy

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Waveguide opinions?
« on: 12 Oct 2017, 03:42 am »

I contemplated, but did not buy in time, the constant directivity waveguides. 

How well do they perform - pros, cons.
Do the Neo ones have a high frequency roll-off, as in the earlier design?
How about for the spiral treble unit?

Thanks for any comments,

Richard

Evoke

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    • EVOKE Planar Loudspeakers
Re: Waveguide opinions?
« Reply #1 on: 12 Oct 2017, 04:16 pm »
I contemplated, but did not buy in time, the constant directivity waveguides. 

How well do they perform - pros, cons.
Do the Neo ones have a high frequency roll-off, as in the earlier design?
How about for the spiral treble unit?

Thanks for any comments,

Richard


Hello, Richard -


This has been a hot topic over the years. If you look at a concert speaker - you will see a horn in front of the actual driver. For example, there may be a 3" compression driver with a very large horn in front of it as a wave guide to control the dispersion of the sound. People who know the sound of unplugged sound often called them "honky". Cup your ears and see if they sound different than without your hand around your ear.


That said, sometimes a positive effect can result. As a designer, I don't see a wave guide impacting the spiral tweeter, and the ribbon wouldn't need one. As for the NEO driver, it can control the vertical field effect, but the nature of the guide acts as a filter that can affect slopes and sensitivity.


With proper positioning of your speakers - distance between, from you, toe in, from back wall, from side walls, space behind you, room reflectivity, you will achieve amazing results. The wave guide won't fix any of those things - but if you do those things I don't think the wave guides would make a difference to the extent that you would ever miss them.


Mark

John Casler

Re: Waveguide opinions?
« Reply #2 on: 12 Oct 2017, 06:08 pm »
Mark is correct and not all understand the WHAT and WHY of seeking constant directivity.

Your gain would be totally dependant on your style of quality listening.

Early loudspeaker design, eventually was focused on a "coverage" goal.  That is, in venues that had large spaces, dispersion/directing the full frequency response evenly over the largest area to be covered.

While this is a goal to even sound to more people at any place in a room or area, it IS NOT always the best goal for a High Performance audio use.

The upside to such wave guides is more even sound distribution no matter where you sit.

The downside, is that the you get more reflected sound and weaker/lower SPL's if you always listen "seriously" in a Sweet Seat.

If all your "serious" listening is done in that position, then your best bet is (with VMPS ribbon monitors) NO CDWG.

If you don't care about the sweet seat, and might benefit from the CDWG then go for it.

That said, due to the reduced specific output when CDWG is used you would need to change the caps to increase SPL's.

Aside from the fact that the WG itself blocks some output, the greater area of directivity reduces SPLs as you get further and further from the driver.

So the simple answer is:

If you always listen in the Sweet Seat = No CDWG
If you listen all over the room, or use the system more for Home Theater, then the CDWG makes sense.


Hipper

Re: Waveguide opinions?
« Reply #3 on: 16 Oct 2017, 06:16 pm »
I concur with John's assessment.

I bought RM30Ms with waveguides in 2004 - the wave guides with a slot for the ribbons.

I found that in use they knocked about 2dB off the volume and made the sound slightly but noticeably  muffled.

As I listen on my own I only use the guides as protection of the drivers when the speakers are not in use. The foam has fallen off anyway.