Setting up a Respectable System for Small Events

[caoimhinn]

Hi all. I work for a company that does a fair number of outdoor employee events during the summer. Typical audience sizes are around 150-200, and typical musical fare is pop and rock. Currently, we use an Anchor Liberty PA, which isn't really appropriate for this application (although it is very convenient). We use it because another department in our company has it for other purposes.

 

We are looking to develop our own system that is reasonably easy to work with, and is powerful enough to produce a respectable sound level for the volume of attendees.

 

To this end, I have been reading up on various types of systems. Powered setups seem to make the most sense for our application; they are easier for non-technical people to work with, and require relatively less time to set up and break down.

 

This past week, I purchased two EV SXA180 subwoofers on Craigslist. They had reasonably good reviews, and seemed to offer a decent way to balance out the low end for our sound. I don't know much about these speakers, except that they purport to output 600W, peak, each, with 18" drivers. I haven't yet purchased tops to complement the subs, but am in the market. As I understand it, they were engineered with the SXA100 tops in mind, so I may start there.

 

I have a few specific questions:

 

1. What is the most sensible way to set up a powered system? My understanding is that I should run my inputs-->mixer-->powered subs-->powered tops. Most mixers I see have TRS out, and not XLR. Is there a problem with using an adapter or a converter cable that will result in sound degradation?

 

2. In "testing" the subs (albeit a very stupid way of testing them [running a laptop 3.5mm output into a 1/4" adapter into an XLR adapter into the sub input] with NO TOPS connected), I was extremely underwhelmed by the output. My desktop computer speakers have apparent comparable SPL. I don't imagine this is merely the result of high expectations from inferior hardware--I think the configuration is either too "stupid" to result in a realistic test, or something is electrically wrong with the amp units. On the other hand, what are thoughts on using a preamp or an amp before sending the signal to the subs? Despite the fact that these subs are powered, what is the risk of damage from using an amplified signal?

 

Thank you again for any advice.

[agedhorse]

Stop testing this way before you damage something. Stupid is probably too strong of a word, but reckless might be more appropriate. If you are using TRS adapters, you will get almost no output because that's not a balanced signal you are generating.

 

You are IMO the ideal customer for the matching EV tops, and then read the manuals (yes, it might reduce the recklessness) and set things up as recommended. They are plenty good speakers for your application. Most mixers do have XLR outputs unless you are looking at the bottom of the foodchain.

 

You are also not a good candidate for buying off of Craig's List. If you don't know exactly hor something is supposed to work, you are the ideal candidate for getting royally screwed... either by your own self or possibly by someone who sees a guppy on the end of the line. Just trying to save you from some costly grief.

[monthlymixcd]

First, welcome to the forum!

 

Second,

 

 

Seriously, though... STOP. Probably best to find someone in your area that knows what they're doing to help you pull a system together... if that's what you really need. If you're only doing a few events every summer it might be better to just rent what you need when you need it. Saves you from having to store and maintain the gear and if you rent you can test drive different systems to see what you really need to buy... if that time comes.

 

Otherwise, do you even know what professional PA subwoofers do?!? Pull up a spec sheet and you'll see that you shouldn't expect a lot of volume out of them for frequencies above 150hz... BY DESIGN. if you haven't already fried those subs them by trying to run amp output into 'em... you might be able to build a system around them. I've never been impressed with the output of the SXA180s (and I hope you got them for cheap), but I suppose they will make decent speaker stands if nothing else. Look at getting a pair of ELX12Ps to put on top of them for starters.

 

Also, you haven't stated whether you're just playing back recorded music or trying to amp up a band... please advise.

[caoimhinn]

Thanks for the responses! And honestly, I do appreciate the bluntness of the replies (if I didn't want or expect it, I wouldn't have posted to a forum).

 

monthlymixcd - As to the question of buying vs purchasing, if we use the system for 8+ events per season, for successive seasons over the service life of the equipment, purchasing makes more sense. That said, there are of course hidden costs, including the learning curve of properly maintaining and using the equipment (and the consequent mistakes that can result from negligent application or handling). They will be used to reproduce recorded music.

 

No, blessedly I haven't connected them to an amplification.

 

In asking if I know what professional PA speakers are engineered to do, I figure you are asking if am expecting them to produce low end sound AND produce high output. Of course, I don't expect that. I expect them to round out the sound of the tops they are paired with. But, I still am left with the sense the the output I'm getting from the above described setup is abnormally low. We used a single QSC KSub for an application in past years that produced a much higher output than what I'm getting with this pair. Certainly, that could be because they are merely different products on different ends of the spectrum.

 

agedhorse - That brings me to your advice; I had considered the issue of the unbalanced input causing a sub-optimal output. But would that matter on such a short run of only a few feet? My understanding of the theory of balanced signals is that the dual signal allows for noise reduction when the cable is picking up interference significant enough to interfere with the sound. I would imagine that the risk of interference rises with the length of cable used, and that a short run used for testing would not be significantly affected. That said, today I will purchase the appropriate cabling.

 

As to the mixers, I probably am indeed looking at the bottom of the food chain. I start seeing XLR outs pop up at around $200. Below that, I mostly see TRS-only. Below that still, I see RCA. I have no interest in the RCA outs, but I do wonder about running a TSR->XLR cable. If balanced, is this going to produce quality similar to XLR->XLR?

 

 

[monthlymixcd]

I might be off base here, but I believe that balanced connections from, say... a mixer's output to the sub(s) send your primary signal (at the proper impedence, mind you) on the Tip of the TRS plug/jack to/from Pin 2 of the corresponding XLR plug/jack AND an out of phase signal along the coductor from the Ring of the TRS plug/jack to Pin 3 of the corresponding XLR plug/jack where the out of phase signal is inverted and combined with the primary signal... making any interference that got into either conductor out of phase with the other... essentially noise-cancelling.

 

What I believe I read that you were doing was trying to plug a STEREO output into a TRS to XLR adapter and then into a balanced input on the sub which will NOT work like you think it would... unless your laptop output was splitting the stereo output into two XLRs (L/R) and then plugging those into the sub... which would only make them unbalanced for a short run, but most likely would not have been at the right impedence for the inputs on the sub(s).

 

 

[nchangin]

Churckle, aged, I don' t know if he was "reckless" more like misinformed, why you gotta be so harsh all the time? Love ya aged (Andy) *** puts up his online shield of happiness and joy ***

 

Why not do it right and get a mixer with balanced outs? then your done, get the matching tops for those subs connect em and use as you intended. Not the best setup in the world (speakers), but the guys your talking to in this forum are Gold Members who do this at the Corporate level of audio. You can always sell them to someone else who is mininformed down the road if need be

 

Any corp event I've dj'd never needed big power anyway, 124 DB more than enough for those kinda gigs in most scenarios.

 

Good mixer is Allen and Heath ZED. Any mixer with balanced XLR outs is good, USB from laptop is even better. Zed has a handy dandy USB port, plug and play into laptop, mic into mixer, mixer to speakers, adjust levels and have at it.I used to do what you did with crappy junk (yes fun ole RCA and 1/4" ick) using adaptors to this and that, buy the right gear the first time and you won't fail. It makes no different between balanced XLR and balanced TRS provided you have the right adaptors that are balanced, however, you get what you pay for.

 

8 shows a year x $200.00 for a dirt cheap dj with a mic is $1600.00 saved. Seems justifiable right?

 

These guys are right, your trying to feed mud into a system expecting it to have diamonds on the output, to make the big diamond you have to feed it a little diamond not mud (going from adaptor to adaptor to adaptor, etc)

 

[Iamthesky]

trying to plug a STEREO output into a TRS

Sometimes I think I should seek out the perfect explanation of this and print it out in large type and small words on cards I can hand out, instead of spending ages trying to breach a fundamental difference in comprehension.

 

For some reason, no-one will stop doing this without an explanation, which they are not prepared to accept.

[RoryMcQ]

You experiment with the sub sounds like what happened when I got my first power amp. I plugged a Shure SM-57 into the XLR input and got hardly any volume, not understanding that the signal needed to go through a preamp first.

[monthlymixcd]

Iamthesky - I know, right?!?

 

OP - Your logic for outfitting your company w/ a capable system is sound, but I've done that before and it inevitably caused headaches down the road... system gets outdated, replacing something that breaks is often a pain ("What do you mean it's broken?!? YOU picked it out for us... isn't it supposed to work perfectly forever? Why did you get something too complicated for us to hook up/operate? Can my kid borrow it for his band to practice with?", etc., etc). Don't set yourself up for headaches later.

[cappttenron]

My advice is get a simple allen and heath Zed. Now you can go direct into a real board with the USB cable from your computer and have nice xlr out. I swear by mine. Second start off with two decent powered speakers like a Yamaha DXR 10, 12 or 15. QSC K series is nice so is EV. Then get a sub or subs that are powered. Done I have the EV zxa1 sub and I am very happy with it but you may want to go with a higher output sub with a 15 or 18 inch. With the Zed you can also do small groups with built in effects much more versatile than a pure dj board. Also for playback virtual DJ is really simple to learn and the basic version is free.

[OneEng]

Love my little ZED 10fx. Solid little mixer, and well worth the $300.00 they go for new for the quality you get.

 

As for the speakers, the subs you picked out will supply some bottom, but not much. At lower volumes, your idea of pairing them with the SXA100's is a good one. I have always liked the tone of EV systems, but I have never heard this one in specific.

[Shaster]

First of all, you should be thankful that agedhorse was particularly kind in his response. But you should also reread his post because he speaks the truth. Secondly, welcome to the forum!

 

Now let's see, the sub you bought is really for lighter weight duty as it's only 300 watts continous and is paired with the SXa100. But it will probably do fine because after all, how loud do you need to be at a company function? So go ahead and get the matching tops, and you'll have a system that's made to work together - and you will not be tempted to play at unreasonable volumes.

 

BTW, the way you were testing the sub was all wrong, so cease and desist. You will find with a mixer, and proper gain, that sub will do nicely and be louder than your computer speakers. Unless you're using a Yorkville LS801P for your computer sub

 

I like the suggestion of an Allen & Heath Zed 10FX mixer if that's enough channels, or get a bigger Zed if needs be. A Soundcraft small format would work as well. In any case, most of the small format mixers that have internal power supplies (which is what you want - NOT a wall wart) have XLR outs.

 

Monthlmixcd was spot on with his comments about company PA's. I've placed a fair number of PA's in schools and am amazed that they're willing to replace their computers every 5 or 6 years but want their PA's to last (and be relevant) as long as the school building lasts. Makes no sense, but there you are. So make sure that folks know that you will periodically need to update or replace mics, stands, cables and so on. and label everything and have a set up, and inventory sheet that others can use.

 

The beauty of a system that's advertised as such, is that some of the heat is off of you. After all you're getting a sanctioned EV system - it must be great, right? And it probably is. Those are nice little top speakers - I've always thought the SXa100 sound / weight ratio was quite good.

[agedhorse]

I was being kind, I did not believe the OP was being stupid at all.

 

A balanced input is looking to see a balanced signal, one that has the program on pin 2 and same program but inverted on pin 3. When run into a balanced (or differential) input, the difference between pin 2 and 3 is the desired signal (+ minus a - = 2+) and signal that is common to both pins is subtracted to a theoretical zero. The problem with using a stereo headphone is that there is no phase inversion so anything that is common to both channels (including almost all bass) is subtracted out.

[monthlymixcd]

Monthlmixcd was spot on with his comments about company PA's. I've placed a fair number of PA's in schools and am amazed that they're willing to replace their computers every 5 or 6 years but want their PA's to last (and be relevant) as long as the school building lasts. Makes no sense' date=' but there you are. So make sure that folks know that you will periodically need to update or replace mics, stands, cables and so on. and label everything and have a set up, and inventory sheet that others can use.[/quote']

 

It should be made clear to any company/school that is considering ownership of their own PA system that they should just plan on an annual budget item for upkeep/maintenance for said system. Unspent accrual of maintenance funds can help offset the cost of large item replacement or future upgrades. Buying used gear is also a bad idea in these cases as the warranties can be a big benefit with numerous people potentially running/destroying the system and any company/organization like a school (or in my case local government) frowns upon buying equipment from anyone that's not an approved vendor (i.e. with no conflict of interest, etc.)