A little help with PA purchase decision Please

[VanGogo]

Coverage is not really the concern. Two tops on either side of an 8ft table typically sound worse than one speaker. The reason is destructive interference. To avoid destructive interference, sources should be placed two wavelengths apart. At 100Hz, a wavelength is 11.3ft, so "tops" should be 22.6ft apart. I place my tops 25ft apart...because my tape measure doesn't have a ".6" mark.

Interesting info! the interference you speak of is phasing right?

For that application, a pair of 312A's will be fine. Run mono, run stereo...it won't make enough difference to matter. The point is to get sound onto the floor...and still let people order at the bar. A sub will improve the "fullness" of the sound, but doesn't really make the overall sound "louder" (e.g....all the frequencies from 100Hz-ish and up will be "the same" with or without a sub...sort of...offloading the <100Hz content from the tops will allow a more power to be put into the mid-bass frequencies but that's going to net <3dB of additional SPL).

I was hoping that would be the case for the small/medium venues. I really don't need to blow the roof off anywhere yet. Just need good sound with enough loudness for the dance floor, to start with anyway.
I do want the "thump" of a sub when I can afford it. As Xonetacular said, that's what people like when they are dancing, to feel the music/beat.

[sss18734]

I am a HUGE fan of DIY speakers. I built 20 for my own use (ten tops + ten subs). Plus I also built all my own road cases.

BUT...there are no good "plate amp" solutions for the DIY builder...so a passive system is really the only viable DIY solution. That means a crossover and amps at a minimum...and for a few more $$$ you really should get a digital PA manager with EQ, limiters, etc. That just isn't going to fit into a <$1k budget. If you have $2k...then DIY cabinets can be a good (but not great) value.

My first PA subs were a big set of 15" MMATS P3.0 car audio subs inside big bass-reflex enclosure I designed, powered off a pair of Behringer EP2500's. I bought all components used... the project ran me about $500 after wiring, mixer, and small crossover. They were ugly, but are pretty comparable to the Yorkville UCS1's I run currently.

[soundinmotiondj]

Interesting info! the interference you speak of is phasing right?

Yes. A google or youtube search for "comb filtering" will have some useful "visualizations." Here are two I found...

I was hoping that would be the case for the small/medium venues. I really don't need to blow the roof off anywhere yet. Just need good sound with enough loudness for the dance floor, to start with anyway.
I do want the "thump" of a sub when I can afford it. As Xonetacular said, that's what people like when they are dancing, to feel the music/beat.

Sounds like you are on the right track.

[VanGogo]

Definitely want to stay in active speaker land for now. The DIY route would be up my alley, but really don't have the time.

I guess the decision is made then....RCF's it will be, with a sub asap. I was thinking that would be the route to take, but as several posts have pointed out the sub is important with dance music and the cheaper options with a sub I was considering were tempting because of the sub.

The one main one sub idea while a good one, would put me over budget for now unless I get a lower quality sub. To keep up the quality I'll wait on the sub.

Thanks for all the info and opinions everyone!

[soundinmotiondj]

My first PA subs were a big set of 15" MMATS P3.0 car audio subs inside big bass-reflex enclosure I designed, powered off a pair of Behringer EP2500's. I bought all components used... the project ran me about $500 after wiring, mixer, and small crossover.

A pair of EP2500's would eat the lions share of your $500 budget. And, car audio speakers are fine...as long as the venue is no larger than the interior of a car.

[VanGogo]

The comb filter videos were great, thanks for posting them!

[sss18734]

A pair of EP2500's would eat the lions share of your $500 budget.

I got them used, for $200. Wait on craigslist long enough and deals do come around.

And, car audio speakers are fine...as long as the venue is no larger than the interior of a car.

Well this is an uneducated statement. They're motors, voice coils, and cones, like any other PA subwoofer.

Car audio speakers can actually be fantastic drivers. The only problem is that they are typically less efficient than their PA counterparts. But since I had a pair of EP2500's, this wasn't really a huge issue. In addition, the size/tuning I had them at helped offset the poor efficiency. They were plenty for bass for most events up to 200 people.

Just judging by ear, the pair was about as loud as a Yorkville LS801P, and had much better low frequency extension... at 1/3 of the price.


Regardless, the OP is not going this route, so lets not worry about it :P

[VanGogo]

The back and forth is educational though

[soundinmotiondj]

Well this is an uneducated statement. They're motors, voice coils, and cones, like any other PA subwoofer.

That is a bit like arguing that "internal combustion engines" are "like any other." I have a V8 in my SUV, and a 4 cycle on my weed eater. Each it really good at what it does, and is well suited to the specific application...but they are hardly interchangeable. As an "audio" example, consider that the 15" driver in a "subwoofer" can not be freely exchanged with a 15" driver in a "full range" cabinet.

It is the total sum of the driver T/S parameters, combined with the enclosure that results in the final performance of a speaker cabinet. To claim that the audio engineers who design woofers are not capable of optimizing one woofer for a car and another woofer for a concert venue is *really* insulting...and an uneducated statement.

Just judging by ear, the pair was about as loud as a Yorkville LS801P, and had better low frequency extension... at 1/3 of the price.

This is not directed at you in particular...but at all humans.. Your ears *suck* as measurement devices. Mood, fatigue level, recent noise exposure, and thousands of other things alter your perception of sound. Look at the "equal loudness" curve for a brief introduction to the field of psychoacoustics to find out more.

[sss18734]

It is the total sum of the driver T/S parameters, combined with the enclosure that results in the final performance of a speaker cabinet. To claim that the audio engineers who design woofers are not capable of optimizing one woofer for a car and another woofer for a concert venue is *really* insulting...and an uneducated statement.

Right... optimized. Comparing this to a V8 on a truck vs a 4 cycle weedeater engine is like comparing a tweeter to a sub.

You're right. CA subs aren't at all optimized for PA applications because they are high-excursion, low-efficiency drivers. This does not, however, mean that they necessarily make poor drivers given enough power.

We all know how little graphs and microphone measurements really matter to the end user. I never did RTA my subs, but they filled my venues just as well as the LS801P that I had been renting for quite some time, and had noticeably better low end extension. Sure, I could have dropped $500 on some crappy entry-level PA gear... but I wouldn't have had a fraction of the performance.

Yes, the combined subs had more cone area, larger combined enclosures, and more power - so they were certainly not optimized like the LS801P was. But they did exactly what they were supposed to due to the box design. I actually threw them in my truck to test them out and they actually fared quite poorly inside the car environment.

All I'm saying is that anyone who has basic knowledge with design software can build a pair of subs that easily outperforms anything in its manufacturer alternative price range - even using CA drivers.