Basic questions about a 2-way 12" & horn PA top

[chips and palsa]

Hey guys quick questions about putting together some quick cabs for a friend.

I am planning on using the Selenium D220 driver with the Dayton HS6512 horn. Originally planned on the Dayton PA310 but read some unfavorable reviews. May go with some eminence drivers instead.

Crossing with subs around 100 Hz, don't need much performance past that.

Just looking for some tips as far as baffle layout (ex horn / woofer spacing) and crossover design tips. Thanks!!

[Brian Steele]

Re: Basic questions about a 2-way 12" & horn PA top

Unfavourable reviews of the PA310? I'd be interested in seeing those, because it appears to be a decent driver for the price. I own one, BTW.

[chips and palsa]

Basic questions about a 2-way 12" & horn PA top

I was sad when I saw one too!
I couldn't believe the specs of it for $65.

http://fredt300b.smugmug.com/Hobbies/Speakers/132721_kcDVmw/1116777949_2FdJtqR#!i=1116777949&k=2FdJtqR

And this thread

http://www.audiokarma.org/forums/archive/index.php/t-150939-p-50.html

I will however be running these through a behringer iNUKE DSP amp so a parametric EQ cut should fix that bump right?

[Paul O]

Re: Basic questions about a 2-way 12" & horn PA top

Hey guys quick questions about putting together some quick cabs for a friend.

I am planning on using the Selenium D220 driver with the Dayton HS6512 horn.
Crossing with subs around 100 Hz, don't need much performance past that.

Just looking for some tips as far as baffle layout (ex horn / woofer spacing) and crossover design tips. Thanks!!

For 100hz up consider using a sealed box, and keep the woofer and horn as close to one another as possible. Crossover will be determined by the drivers used but otherwise it's no different than any other speaker, use complementary slopes and make sure the components can handle the power the system will see.

[chips and palsa]

Re: Basic questions about a 2-way 12" & horn PA top

Do the ports add to what that user was describing as muddy response?

Also, does the crossover help deal with the large efficiency differential between the woofer and horn? Or will I need to rely on the DSP for that? Have seen suggestions by some to use the 16ohm CD horn to deal with the sensitivity but others have commented that it can ruin change the behavior of the crossover completely.

[chips and palsa]

Re: Basic questions about a 2-way 12" & horn PA top

Unfavourable reviews of the PA310? I'd be interested in seeing those, because it appears to be a decent driver for the price. I own one, BTW.

What kind of application are you using this 310 for?

[billfitzmaurice]

Re: Basic questions about a 2-way 12" & horn PA top

Originally planned on the Dayton PA310 but read some unfavorable reviews.

The only unfavorable review I saw on the PE site was from someone who obviously was clueless. I wouldn't put any stock in the linked review without seeing details of the design, crossover and measured SPL charts. Since 'fred' used a 25 ohm series resistor for padding the tweeter, instead of a properly configured LPad, I wouldn't put a lot of faith in his level of expertise either.

For 100hz up consider using a sealed box,

+1, with the caveat that it gives the desired response and output in a sealed box. Most high quality pro-sound woofers won't, having high Fs and low Qts that works better in a VB, even used only to 100Hz. You must model whatever you're considering to be sure.

Just looking for some tips as far as baffle layout (ex horn / woofer spacing) and crossover design tips.

The asking of that question tells me that you should consider a tested design, saving yourself a lot of potential grief.

[chips and palsa]

Re: Basic questions about a 2-way 12" & horn PA top

Fair enough Bill. I found a Selenium CD and Delta 12 crossover schematic that I would use.

The issue is that this far, I haven't found an plan! You'd think such a simple setup would be everywhere. The tempest and econowave variants all look like HT setups but if all I have to add are ports handles and a top hat I have WinISD on my side

[jefffluker]

Re: Basic questions about a 2-way 12" & horn PA top

Email me. [email protected]

Better still, call me. 985.543.0057

Jeff

[chips and palsa]

Re: Basic questions about a 2-way 12" & horn PA top

Cool thanks Jeff, I'm really starting to notice the popularity of these trapezoid 2-way boxes. And simmed the B&C 12" box and why do you know! It performs exactly as it says! The benefits of expensive drivers =(

[Brian Steele]

Re: Basic questions about a 2-way 12" & horn PA top

Do the ports add to what that user was describing as muddy response?

It's possible, though those vents look a bit short to result in a peak near 500 Hz as the builder indicated. It's more likely that the peak may have been caused by resonance in a poorly-damped enclosure that made its way through the vents. I'm seeing what seems to be bare wood visible through one of the vents and that's always a sign of a poorly-damped full range enclosure IMO. All sides of the enclosure should at least be lined, and FWIW I actually prefer the sound of a fully-stuffed enclosure (light stuffing if being used in a vented alignment).

I note that the builder recommended an Eminence driver instead, but he used that driver in an entirely different enclosure with the vents placed to the rear of the cabinet.

[Brian Steele]

Re: Basic questions about a 2-way 12" & horn PA top

What kind of application are you using this 310 for?

It's for a TH design, so its response above 100Hz or so isn't all that important to me. However during my testing of the PA310, I didn't notice anything that would discount its use in a full-range design IMO.

[chips and palsa]

Basic questions about a 2-way 12" & horn PA top

I'm finding that with most of these lower priced drivers it's difficult to get a response without a huge peak around the tuning frequency in a normal sized cab (40-50 liters) also, the Dayton has a very high port velocity around 100Hz if using less than 4 - 4" ports where as the B&C in comparison has a much flatter response, will not max excursion at full continuous power (same 5mm Xmax as Dayton) and maintains a low port velocity with half the 4" tubes. Wondering what TS specs are accounting for that nice behavior...

[Sydney]

Re: Basic questions about a 2-way 12" & horn PA top

...I'm really starting to notice the popularity of these trapezoid 2-way boxes. And simmed the B&C ...

While there may be a design reason for trapezoid boxes in high end professional speakers ( Meyer for example ) , often it is used as a marketing gimmick in low end gear emulating the look of others.
FWIW: BSC is not designed into PA tops for a variety of reasons

[billfitzmaurice]

Re: Basic questions about a 2-way 12" & horn PA top

I'm finding that with most of these lower priced drivers it's difficult to get a response without a huge peak around the tuning frequency in a normal sized cab (40-50 liters)

The first thing you want to do when considering a driver is to model it in WinISD Pro, letting the program go to the default maximally flat alignment. With the PA 310 that's 39L (net) with 45 Hz tuning, and there is no response hump. If you are seeing a big response hump when modeling that means the driver Q is too high to work well in a VB.
As to vented or sealed, the PA 310 in a 23L box has a 0.7 Qtc, with a 100Hz f3, so one might be inclined to say that's fine with a 100Hz crossover to subs. But that's in half-space, which you don't get with the speaker on a pole where it needs to be. Doing a bit of alignment jamming you can put it in a 30L box tuned to 60Hz. That gives a bit of a 100Hz bump, but nothing severe, and when up on a pole in free-space that bump won't be there. I do this with my Simplexx 12 loaded with the Beta 12CX for just this reason, to compensate for the speaker not being on the floor.
As to the port velocity issue, with a 30L 60Hz box and a single 4 inch port I'm not seeing any problems up to 300w within the 100Hz and higher passband.