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[Ivan Beaver]

V/H at what frequency?  (channeling Ivan).

You beat me to it

Even with the best products, the actual pattern varies a good bit with freq.

Some a whole lot, and others not so much.

And this is within the freq range that the horn is actually large enough to have pattern control.

Many people "assume" (wrongly) that the rated pattern is over most of the freq range.

Just look at the questions about speakers that have 6" horn that are "rotateable"-so that they can "attempt" to keep the energy off of the walls..

But in the narrow dimension, often the horn only controls above 6 or 8KHz and up.

Not exactly what I would worry about.  The rest just "splatters" everywhere.

Size matters.  Just do the simple math:

Freq of control=1,000,000/(size of horn in inches x rated pattern in degrees)

The size of the horn is NOT the outside of the mounting flange and in many cases it is smaller than the outer edge of the actual horn, and somewhere inbetween the flare break and the outer edge.  But just use the outer edge for ease of measurement.  The actual freq will be a little higher than the calculation due to this.

This can be quite eye opening.

[Jeff Lelko]

Laser lights built into speakers to help speaker aim and placement.

I can’t comment about the aim and placement aspect of it, but they already make speakers with built-in lights and lasers.  I had the unfortunate opportunity to experience one recently when a random “DJ” showed up with such a box, plopped it down in the middle of the stage, and started jamming with it right in the middle of my load-out.  Neither I, my client, nor the venue owner knew who he was or where he came from...

[Dave Garoutte]

It'd be adjustable, so you can play with the rectangle until it matches the coverage in a useful way.  The idea is that it would help with adjusting your tilt and general placement.  You still need to use your ears, but like any tool, it could speed things up.

[Steve M Smith]

A few years ago, I made an XLR lead tester which works on phantom power... then found out that Dave Rat sold one under his Sound Tools banner.

If anyone wants to make one...




Steve.

[Mark Wilkinson]

Ok, here's my "creative" work in progress, although creative is really stretching it...it's more just taking things i like from stuff I have, and recombining / re-purposing.

It's a ground-stack, designed-to-array, modular main, meant for easy one person transport and set up....and of course to make more noise
Basically, it's the drivers from Peter Morris's DIYs, put in two boxes that stack up to mimic Peter's double 10" and Jeff's 3TX, but using double 12's. It's also Peter's recommended x-over points etc.  Guys, please accept the old 'imitation is the sincerest form of flattery' accolade

I wouldn't be thinking this design has anything to do with creative, except for a few little twists.
 
I've put the compression driver and its horn in a box of their own, with rubber feet on the front of the box that fit into recesses on the top of the mid box, and a rear swivel jack bolt that allows a variable downward angle. So I get easy down tilt for 650Hz up...(xover to CD)

Also, by making the CD & horn box separate, I can change coverage patterns really easy.  The first pict shows 4 different horns...folks might recognize the horns from the PM90 and PM60, and the 3TX 60 & 90. 

The 12"s mid box is a "I don't really know what type it is"...I guess maybe a tapered pipe.  Rear volume expands top down to port.
My measuring skills are a lot better than my modeling skills, so I just used trial and error to get the best raw response I could. 
It's size and angles were determined by the size of the box for the largest CD/horn I wanted to use, and specifically the splay angle that measured best for that. Easy to array was one of the main objectives.
 
The mid weighs 47lbs without grill. The CD box weighs 23lbs with the heaviest driver/horn.
The combo is 48" tall, which puts the horn center almost 3 1/2 ft above the subs.
They're light enough I can carry them up a step ladder to stack on top of subs 6ft high, if I want to go that high.
It's totally a ground stack idea....I just couldn't get comfortable last season with near 80lb boxes on stands, even on fairly robust st-132's.
Debbie's recent pole dancer story reconfirmed my paranoia  lol

I haven't been able to do a mid section sensitivity comparison to the PM boxes yet, but it appears it's gonna be closer than i hoped.  The horns are the same, so it should be a pretty loud box. I heard  the PM60 against a srx 835p and there was at least a 6dB difference I think. 
I'm hoping two of my stacks a side will crank some serious lounge level volume.

I know there are no doubt a million ways I could improve this design...it's a first try for me, built around specific compromises. Go easy on me !
Looking forward to making off-axis measurements.  On axis tuning sounds great so far....



 

[Chris Grimshaw]

Ok, here's my "creative" work in progress, although creative is really stretching it...it's more just taking things i like from stuff I have, and recombining / re-purposing.

Hi Mark,

If you can get a dimensioned sketch of the internals to me, I'd be happy to throw together a Hornresp simulation and see what you've come up with.

Chris

[Mark Wilkinson]

Hi Mark,

If you can get a dimensioned sketch of the internals to me, I'd be happy to throw together a Hornresp simulation and see what you've come up with.

Chris

Hi Chris, that would be great thx! 
It will probably make me sick, seeing how much I've left of the table ! 
But I REALLY do need to learn Hornresp.  I was getting fairly decent sim matching as long as I stayed with a rectangular box and one 12".
When I went to 2 12"'s and trapped box with a small mouth extension, well.....I gave up ....

I'll PM you some picts and measurements, surely before weekend is over...OK?

[Ivan Beaver]

Ok, here's my "creative" work in progress, although creative is really stretching it...it's more just taking things i like from stuff I have, and recombining / re-purposing.

It's a ground-stack, designed-to-array, modular main, meant for easy one person transport and set up....and of course to make more noise
Basically, it's the drivers from Peter Morris's DIYs, put in two boxes that stack up to mimic Peter's double 10" and Jeff's 3TX, but using double 12's. It's also Peter's recommended x-over points etc.  Guys, please accept the old 'imitation is the sincerest form of flattery' accolade

I wouldn't be thinking this design has anything to do with creative, except for a few little twists.
 
I've put the compression driver and its horn in a box of their own, with rubber feet on the front of the box that fit into recesses on the top of the mid box, and a rear swivel jack bolt that allows a variable downward angle. So I get easy down tilt for 650Hz up...(xover to CD)

Also, by making the CD & horn box separate, I can change coverage patterns really easy.  The first pict shows 4 different horns...folks might recognize the horns from the PM90 and PM60, and the 3TX 60 & 90. 

Here is the "basic problem".

It all has to do with distance between drivers and the different arrival times at different seats.

Unless the drivers are within 1/4 wavelength of each other around xover freq, you will have differing combfiltering at different seats.

But if the flexibility of the system is more important than sonic character, then don't worry about it.

But there is a reason(s) speaker designs have moved away from the separate box approach.

[Rob Spence]

A great feature for a multi box design would be integrated hardware for attaching the boxes together, similar to line array cabinets.
Also, a clever way to extend the rear foot (feet?) on the horn to specific angles quickly.
I find most of the hassle of ground stacking is the kludge of strapping the pile in place.



Sent from my iPad using Tapatalk Pro

[Mark Wilkinson]

Here is the "basic problem".

It all has to do with distance between drivers and the different arrival times at different seats.

Unless the drivers are within 1/4 wavelength of each other around xover freq, you will have differing combfiltering at different seats.

But if the flexibility of the system is more important than sonic character, then don't worry about it.

But there is a reason(s) speaker designs have moved away from the separate box approach.

Yep, I totally get all that. 

Peter's dipole mid, straddling the HF horn definitely acts a bit better towards being a point source. I've already measured that...

On my stack-ems, I could tighten up center-to-center a couple of inches between mid and HF if all were in one box...but it's not worth it for what I was trying to do. Get horn higher, lighten pieces, give flexibility to use different horns/drivers, be able to tilt horn, be able to array easier, be able to experiment easier....

I do feel i am able to mitigate c-to-c issues a bit because I've learned to tune with much higher x-over slopes than are normally used (96dB/oct), without latency or ringing issues once past about 300Hz.  (Mid-to-high is 650 on these, subject to further development.)

And really, the more I play around, the less I'm getting concerned with lobing issues if they are not too out of hand.
I mean, there's so many non-optimal factors usually in play, a little lobing/combing 'never hurt anybody'
For instance, how often is the sub-to-main handshake within 1/4 wavelength throughout  summation range? Or co-located?

[ProSoundWeb Community]