Super Tweeter. Dispersion make much difference? Also, preference?

I use the APT150 in my PA cabs and it works well, but those are 3-ways. It'll give you clean top that doesn't sound harsh at all if you don't try to make it play lower than it's supposed to. It's not what you want to meet the top of a woofer in a 2-way. I always favor wide horizontal dispersion in favor of less vertical. Audiences may be as wide as you have room for, but the difference in ear level between a tall person standing and a short person sitting may still be only 4 feet.

 

Are you planning on a stack or a single cab? The reason I ask is because lately I've heard a lot of people say that as rigs get smaller/lighter/more powerful they are able to get by with just one cabinet but....have to tilt it back because they can't hear note definition with the single cab being so far below ear level. This is particularly true on small stages where you can't get very far away from your rig.

So based on that I'd say that vertical dispersion (like the Eminence square model) would be a big plus. Otherwise, maximum horizontal dispersion would seem logical in able to get consistent coverage in small gigs without P.A. support.

 

Well put, brother

 

I have multi-directional tweeters on my home stereo and they do make a big difference when walking around the room.
As for bass guitar, it will help you hear yourself if you like to move around the stage. Bass frequencies tend to bloom outward regardless but mids + hids can get lost.
I would pick the third one for "wider" dispersion.

 

Throw the Selenium D220Ti driver on their HC23-25 40x100 horn in your mix. Loud, smooth, and can handle being passed lower.

 

I try to get a decent pattern match between woofer(s) and horn in the crossover region. That implies choosing woofers with the crossover in mind, so now we're talking about pretty much the whole system design...

Of the tweeters you mention, the APT-200 is the one I'd lean towards, but it's stick-out-ness makes it a bit less practical in a gigging cab. Next choice would be the APT-150.

The Selenium driver Will33 mentions is a PA-capable driver, and imo does outclass the little driver on the APT models.

 

Go with the widest possible horizontal dispersion. Anything sent towards either the floor or ceiling is wasted.

 

I've often wondered what this type of pattern matching is doing to my 212's with a single 6 offset to the upper left. It sounds good, but I haven't dug all the way into analizing patterns with each other. The single 6 driver having a conical pattern in it's sweet spot vs. the vertical pair of 12's putting out a little more straight forward in their pattern. With the active crossover in the bass amp, it does sound a bit like separate parts up close to the rig. You don't have to get too far away before it melds together and out in the room, it's just your bass sound spread out pretty good. But getting smoother sound from the source would translate into better sound from there all the way down the line.

 

Dissimilar patterns can still work well together, but it's a bit more of a juggling act in the crossover region. You have to make tradeoffs between the on-axis response and the power response. I would give greater weight to the power response, but it's a judgment call.

 

Wow...two of the smartest designers in the world helping someone figure out how to set up a cab...gotta love this place

How ya doing, Duke?!

 

There is more to HF horn design than dispersion pattern...
Having used the above mentioned Eminence units, I'd say the APT-200 is the best sounding horn in the bunch for your application. I would not choose a horn with very small vertical dispersion. It makes it hard to hear the HF if you do not have the tweeter on or close to ear level.

Regardless what horn you choose, do yourself a favor and replace the sub par Eminence HF "driver" and put in something better. I machined throat adaptors that allowed me to fit Beyma HF drivers to the APT-200 horns and that is huge improvement in sound quality. Very noticable even for electric bass.

And do not overlook the Selenium ST 300/304 tweeter! Far better than Eminence, but at similar cost. This one is used in the EBS ProLine cabinets favored by many bass players that need a clear and bright sound for slapping, chording etc.
Find it here:
http://www.parts-express.com/wizards/searchResults.cfm?FTR=selenium+tweeter&search_type=main&WebPage_ID=3&searchFilter=selenium+tweeter

 

It's not on the list and the dispersion is 90 x 60, but it's one of the best tweets I've ever had in a bass cab ( with two vertical stacked 3012HO's.

XD125 - HF Compression Driver

 

+1. There will always be compromises. The main problem with cone/cone is that a twelve might have 90 degree dispersion at the crossover, while a six might have 160 degree dispersion at the same frequency, so there's a very large difference in the polar response within a very small bandwidth. A horn has the advantage of pattern control to get its dispersion much closer to that of the woofer at the crossover frequency, but the disadvantage is cost. A cone six capable of going to 1.5kHz or so can be much lower in cost than a compression driver and horn.

 

When biamping actively, the power response, or rather power input I guess you'd call it, is adjustable, easy to get different voicings or match up with the low side, but i guess there isn't much you can do about the pattern, eh? Move the 6 over so they at least line up in one plane? I guess that's one more excuse to change it all to a woofer/mid/woofer alignment other than it's something different, it looks cool, gets the mid out of your ear, and something about vertical pattern control I don't yet fully understand.

Hijacking the thread here....back to HF horns. Somebody had a good point in there about going too narrow vertically for up close personal monitoring if it's a short cab. I was thinking more audience coverage as wide as you can get it and pattern matching be damned.

 

I should have defined my terms. "Power response" means "the sum total of a speaker's output across all angles", or "the summed omnidirectional response of a speaker". So if a cone speaker has a flat on-axis response, as its pattern narrows with rising frequency ("beaming"), its power response slopes down. Or if a cone speaker has flat power response, then it has a rising on-axis response in the region where it's beaming.

In a reverberant or semi-reverberant environment, the farther back in the audience we are, greater the contribution of the reverberant sound relative to the direct sound. And the spectral balance of the reverberant sound is dominated by the power response, modified of course by the room's acoustics. It is only fairly close to the speakers that the direct sound delivers more energy than the reverberant sound, and of course the spectral balance of that direct sound depends on the angle (standing beside a cab that's on the floor gives a very different direct sound than standing out in front of it).

If a horn has constant directivity in both the horizontal and vertical planes, then its power response tracks its on-axis response pretty well. So as we EQ to correct the on-axis response, we are simultaneously correcting the off-axis response; we don't have to choose one at the expense of the other. But in turn one of the downsides of constant directivity horns is greater crossover complexity and cost.

Some PA cabs use horns that have constant directivity in the horizontal plane (for good horizontal coverage) but narrowing directivity in the vertical plane, as this does a better job of directing the precious high frequency energy where it's needed most. I say "precious" because usually the efficiency of a compression driver at high frequencies is considerably lower than its efficiency in the midrange.

 

Now I get it, makes total sense. Thanks, Duke. And no, you don't have to define your terms, those are common design terms I should know or look up for myself.

 

I know a guy who uses the D220Ti and loves it. Can't remember which horn he has though. It isn't either of those. But both those horns look great.