Please vet this idea for a dual horn midrange/HF speaker

[chris661]

Yes, of course.
Something like 15MB650 will easily outperform 3” array in terms of nearfield pressure and upper-midbass/low-midrange band.
But lets see far from soundstage?
First.
15” will drop -6 dB with distance doubling
3” array will drop -3 dB with distance doubling up to 40-60 meters.

This will result in much more even loudness over stadium.

Only applies at high frequencies, where the line array is very much larger than the wavelength.
500Hz has a 68cm wavelength, so the line of speakers will still act as a point source there. Now we have some frequencies with -3dB per doubling of distance, and others with -6dB!
That will be a very bright sound with lots of treble for those sitting further away.
This, IMO, is the big flaw with column type speakers.

There's also the treble beaming from the 3" wide diaphragm. 12kHz will be a laserbeam.

Chris

 

[conanski]

Now I'm looking at the easiest way to mount the woofer and horn. I guess I could just mount them both to a plank of wood, but I'm thinking of cannibalizing some trash like these Rockville RSG8 speakers. They're $85 for a pair, including shipping. I'd toss the driver and tweeters, and cut a slot above the driver for the horn.

Oh.. make a separate mid/hi box? That would work, you may get tired of moving the pair though so some new boxes would be a good idea at some point.

 

[gj00023]

Oh.. make a separate mid/hi box? That would work, you may get tired of moving the pair though so some new boxes would be a good idea at some point.

I'll probably build new boxes when I get a wood shop set up again. That might be awhile, and I'm bringing my PA to a 5-day free outdoor party in a few weeks, so I'm trying to rush something together for that.

Do you have any suggestions on what angle of dispersion to get for the horn for the compression driver? I'm inclined to go as wide as possible, but I'm open to any wisdom you or anyone else has on that.

 

[conanski]

90 degrees would be a good fit for your application I would think. One benefit of having the mids and highs in a separate box is that you can tilt them relative to the other boxes and that will help put sound where you want it then everything is stacked up.

 

[gj00023]

90 degrees would be a good fit for your application I would think. One benefit of having the mids and highs in a separate box is that you can tilt them relative to the other boxes and that will help put sound where you want it then everything is stacked up.

Thank you. Tilting the mids/highs does sound like it could be a plus. Do you mean 90x90, or the more typical 90x40? What is the advantage of a 90x40 versus this 100x80? (And for what it's worth, I'm more concerned with the sound at high SPL outdoors than what it sounds like in my house.)

 

[BesPav]

What is the advantage of a 90x40 versus this 100x80

Wider angle needed for short throw, i.e. closer placement to listeners. Any system need to be balanced between LF/MF/HF ratios.

LF are mostly omnisource, but high-power not a problem.
MF are more directional and more or less power-limited
HF are only directional, drivers are very sensitive and power-limited.

So you need to properly tune theese three around your PA space keeping in mind speakers placement, available power, dispersion, delays and needed levels.

 

[conanski]

Do you mean 90x90, or the more typical 90x40?

90x40.

What is the advantage of a 90x40 versus this 100x80?

A large vertical dispersion is rarely useful with a PA system as that energy will just be projected up into the sky and wasted when outdoors or if indoors splashed on the walls/ceiling where it will muddy and create reverb. And consider that for any given input voltage the driver produces the same output, the horn then determines how much area that energy will cover and the bigger the area the lower the average sound intensity will be. If the system will be used for mostly near field listening then a wide angle horn is best, if you want more energy further away then select a narrower horn.

 

[freddi]

here's one of JBL's 6.5" waveguide $50 seems a bit steep - perhaps it could be found cheaper. The plastic is thin so a reinforcing ring at the mounting flange might help WAVE GUIDE PRX535 - JBL - JBL Audio Spare Parts

here's the way mine looked on-axis

and with simple cap highpass

driver used

 

[gj00023]

I ended up just buying a pair of Yorkville U15 speakers and wow, they're pretty sweet.