PA Speaker Project

[alcavalier]

As a 1st timer, I'm trying to design a PA system to use for DJ and small band gigs and would like to know if I'm heading in the right direction.
I'm planning to tri amp with 1 QSC GX5 and 2 QSC GX3's along with a dbx 234 2/3/4 way crossover.
My choices for drivers are currently 1 Dayton DCS380-4 15" Subwoofer in it's own enclosure with a possibility of adding another identical enclosure later.
For Mids/Highs I am thinking of builing 2 enclosures with EACH having 2 Selenium (either 6W4P 6" or 8W4P 8", still haven't decided) woofers and 1 Selenium DT150 Super Tweeter 4x4 horn.
I'm planning to crossover at 150Hz and 4KHz.
The super tweeter is listed as 1.5KHz-15KHz.
**Question - Is this a high enough freq.? Others that are listed as higher (up to 27KHz) are rated at a much lower wattage.
Was just wondering if someone with lots more expertise could look over this design and make recommendations/comments.

Thanks in advance,
Al Cavalier

[subsonic]

> As a 1st timer, I'm trying to design a PA
> system to use for DJ and small band gigs and
> would like to know if I'm heading in the
> right direction.
> I'm planning to tri amp with 1 QSC GX5 and 2
> QSC GX3's along with a dbx 234 2/3/4 way
> crossover.
> My choices for drivers are currently 1
> Dayton DCS380-4 15" Subwoofer in it's
> own enclosure with a possibility of adding
> another identical enclosure later.
> For Mids/Highs I am thinking of builing 2
> enclosures with EACH having 2 Selenium
> (either 6W4P 6" or 8W4P 8", still
> haven't decided) woofers and 1 Selenium
> DT150 Super Tweeter 4x4 horn.
> I'm planning to crossover at 150Hz and 4KHz.
> The super tweeter is listed as 1.5KHz-15KHz.
> **Question - Is this a high enough freq.?
> Others that are listed as higher (up to
> 27KHz) are rated at a much lower wattage.
> Was just wondering if someone with lots more
> expertise could look over this design and
> make recommendations/comments.

> Thanks in advance,
> Al Cavalier

I'd go with a bigger midbass like 10 or 12"
and a 1" compression driver with a big wave guide.

[unknownuser]

> As a 1st timer, I'm trying to design a PA
> system to use for DJ and small band gigs and
> would like to know if I'm heading in the
> right direction.
> I'm planning to tri amp with 1 QSC GX5 and 2
> QSC GX3's along with a dbx 234 2/3/4 way
> crossover.
> My choices for drivers are currently 1
> Dayton DCS380-4 15" Subwoofer in it's
> own enclosure with a possibility of adding
> another identical enclosure later.
> For Mids/Highs I am thinking of builing 2
> enclosures with EACH having 2 Selenium
> (either 6W4P 6" or 8W4P 8", still
> haven't decided) woofers and 1 Selenium
> DT150 Super Tweeter 4x4 horn.
> I'm planning to crossover at 150Hz and 4KHz.
> The super tweeter is listed as 1.5KHz-15KHz.
> **Question - Is this a high enough freq.?
> Others that are listed as higher (up to
> 27KHz) are rated at a much lower wattage.
> Was just wondering if someone with lots more
> expertise could look over this design and
> make recommendations/comments.

The woofer looks like a very good value, and could probably cross over up to 500 Hz. You can always adjust this with your crossover.

The 6" midrange looks very good. It has a spike at 4000Hz, which is where it will sound harsh. So, you should cross it over an octave below that, at 2000Hz or lower.

The 8" midrange is efficient, but I would not want to cross it over at 2000Hz without hearing it first, it looks like trouble up there. But, I could be wrong.

The Eminence Alpha-6A 6" Midrange, Part Number 290-400 looks nice, and I like Eminence drivers. But, it costs more than the Selenium, and I think it would sound better. But, I don't know if it sounds that much better. Eminence also makes some good 8" midranges.

It looks like you should have a tweeter that can cross over around 2000Hz. The Selenium D210Ti 1" Titanium Horn Driver, Part Number 264-235 is on sale now, and gets some good reviews. I would recommend this tweeter with an 8" waveguide, or shallow horn.

I don't think a super tweeter would be a good match for most midrange cones.

So, that is my recommendation. The Dayton DCS380-4 15" woofer crossed over about 350Hz. One Selenium
6W4P 6" midrange, or Eminence 6" midrange. And 1 Selenium D210Ti 1" Titanium Horn Driver with a waveguide.

This will be a good sounding system. You could use a passive crossover for the tweeter and use less amplifier channels.

I am not sure how well the Dayton woofer will hold up being moved around from place to place. When I asked Parts Express for advice on woofers they said Eminence was worth the money compared to less expensive drivers. You can always upgrade the woofer, or add another pair of woofers if needed.




(Originally posted by: SteveF)

[Paul O]

I suggest you make the mains a 3way cab with a 10 or 12" low frequency driver, single 6" mid and 1" compression horn with crossovers of 500hz and 2khz. The dual 6" mids would suffice for recorded music but will be woefully inadequate for live sound reinforcement where you need to support lots of mid bass content. A compromise is to go back to a 2-way in a 12+1 format.
The Dayton sub has no business in this setup at all, you need to utilize at least a pair of pro audio sub drivers in reflex cabs that are capable of 6db more output than the mains. If you use horn loaded subs you'll get away with cheaper drivers and will need less amplifier power, but the boxes will be bigger. Sub to mains crossover should be no higher than 100hz in most cases.

[Max_Andrews]

I agree that you should be looking at a horn-loaded subwoofer. A regular sub will not be able to keep up with the rest of the system in terms of output. billfitzmaurice.com has some great horn loaded sub plans for a small fee. Maybe the tuba 24/30 design is more in line with your goals.

For the mains, I'd go with a 10" driver and a tweeter w/waveguide in a smallish sealed box. You'll be using the sub anyways, so having mains that go deep isn't an issue, and the smaller size and weight of the cabinets compared to vented boxes will make setting up and moving them a lot easier.

For the woofer I'd suggest the BP102 10" driver: <A HREF="http://www.partsexpress.com/pe/pshow...number=290-471">http://www.partsexpress.com/pe/pshow...number=290-471</A>

A widely acclaimed driver with lots of excursion and a warm midbass region makes it ideal for use as a suspended main (i.e., a speaker on a stand in the middle of a room). Cross it to the subwoofer at 100hz, the tweeter at 2000hz, and you're set.

For the tweeter I'd suggest the selenium D210: <A HREF="http://www.partsexpress.com/pe/showd...number=264-235">http://www.partsexpress.com/pe/showd...number=264-235</A>
Cross it at around 2000hz.

Use this for the tweeter horn: <A HREF="http://www.partsexpress.com/pe/showd...number=270-310">http://www.partsexpress.com/pe/showd...number=270-310</A>
It will work better than the biradial style horns as it will have uniform dispersion rather than confined to two axes. Cross the tweeter at 2khz.

Instead of the dbx crossover, I'd recommend a pair of the behringer DCX2310 models run in mono mode: <A HREF="http://www.partsexpress.com/pe/showd...number=248-664">http://www.partsexpress.com/pe/showd...number=248-664</A>

They have a separately adjustable subwoofer output, so you can adjust the point of rolloff for the subwoofer and the mains separately, making it easy to get the right balance. There will likelt be a bit of overlap between the woofer and tweeter in the response around 2khz, due to the horn loading on the tweeter and the breakup from the woofer, which you'd have with any woofer and tweeter. You could either equalize it out, or put a simple passive circuit on the woofer which would be an inductor in series and a zobel (resistor and capacitor) in parallel. This circuit would reduce the breakup and therefore reduce the spike in response at 2khz. I'd have to model it to give you the exact values, which I can do on monday if you want.

And even better solution if it's within yor price range is to get a single DCX2496: <A HREF="http://www.partsexpress.com/pe/showd...number=248-669">http://www.partsexpress.com/pe/showd...number=248-669</A>

This allows you to adjust the slope and position of each filter, to blend the drivers together perfectly.

Hope I've given you a few good ideas to work from.
-Max