Help with school PA system - diyAudio
Go Back   Home > Forums > Live Sound > PA Systems

PA Systems A forum for discussion of all parts of a sound reinforcement or DJ system: loudspeakers, mixers (desks) etc.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 31st August 2012, 02:18 AM   #1
diyAudio Member
 
Join Date: Aug 2012
Default Help with school PA system

Hello everyone, hopefully someone can point me in the right direction.

My daughter's high school football stadium PA system just sounds horrible. She's in her senior year and for 4 years I've sat in the stands listening to people complain how bad the system sounds. So I decided enough is enough and trying to do something about it. It's a relatively small stadium setting, probably around 1000-1500 people.

The vocal sound from the microphone sounds ok, but when they play music, the speakers sound blown, with way too much bass and zero clarity.

So before I break down and start spending way to much money for new speakers, I was hoping for some advise on how to troubleshoot.

The system consists of a pair of EV sx300 outdoor speakers, a Samson sx 1200 amplifier, with a Tapco Mix 220fx mixer which a Sony CD player and announcers microphone plugs into. The Tapco plugs into the Samson with XLR connectors. The speakers plug into the Samson with speakon connectors.

Any advise on how to tackle this would be greatly appreciated.
  Reply With Quote
Old 31st August 2012, 03:10 AM   #2
Enzo is offline Enzo  United States
diyAudio Member
 
Join Date: Sep 2004
Location: Lansing, Michigan
Maybe the speakers ARE blown.

You might try connecting a different amp and signal source to them for test. And you might ty some different speakers connected to the amp system. They need not be up a pole, just sit them somewhere and listen to them

What sort of Sony CD player? Does it have line out jacks you are using? Or is it a portable unit and you are using the headphones output?

ANy chance the CD player is overloading the Tapco? Can you conect the CD player directly to the Samson for testing? Can you try some other CD player into your mixer.


Voice has a fairly limited frequency range - it doesn;t have a lot of low bass sounds. Your telephone is a good example. It has a response of something like 300Hz to 3000Hz. That is FAR from hifi, yet in talking to someone, most times you don;t think "gee this sounds crummy."

But music requires a full range of sound. SO your speakers could have shredded woofers and still sound OK for voice. SO we test the speakers, but also test the system. The speakers could be perfectly good, and are faithfully producing crummy sound coming from the system. So we test each part.


The equipment looks good enough for a small PA, but the speakers have only a 12" woofer, so there is a limit to how much bottom end it can produce - especially outdoors. Outdoors is the toughest room to fill with sound. Your system looks good for basicsd, but one addition that Might help would be a graphic equalizer between mixer and amp. That would let you fine tune the overall tonal structure.

How is the mixer being set up for the music channel? You have three-band EQ on each channel, so if your sound is boomy, make sure the EQ on the music channel does not have the LOW control cranked up.

The CD is a stereo signal, so are you going into the Tapco through channel 5/6 or 7/8? Those are set up to receive stereo signals. You could also use two channel in the 1 through 4 group. There is also the CD input jacks, but honestly I don;t recommend using them for use in the PA mix, I use them mainly as a way to listen to something - like while learning a song. Much prefer using 5/6 or 7/8 for CD.
  Reply With Quote
Old 31st August 2012, 04:59 AM   #3
kctess5 is offline kctess5  United States
diyAudio Member
 
Join Date: Dec 2011
Location: California
I'm sorry i cant help much, but my schools system had the same problem. I chalked it up to an inadequately sized system for the venue, leading to excessively THD from both the speakers themselves and the amps. I also decided to do something about it. Now I have building a very large pa system on the schools dime as a senior project
  Reply With Quote
Old 31st August 2012, 12:52 PM   #4
diyAudio Member
 
Join Date: Aug 2012
Quote:
Originally Posted by Enzo View Post
Maybe the speakers ARE blown.

You might try connecting a different amp and signal source to them for test. And you might ty some different speakers connected to the amp system. They need not be up a pole, just sit them somewhere and listen to them

What sort of Sony CD player? Does it have line out jacks you are using? Or is it a portable unit and you are using the headphones output?

ANy chance the CD player is overloading the Tapco? Can you conect the CD player directly to the Samson for testing? Can you try some other CD player into your mixer.


Voice has a fairly limited frequency range - it doesn;t have a lot of low bass sounds. Your telephone is a good example. It has a response of something like 300Hz to 3000Hz. That is FAR from hifi, yet in talking to someone, most times you don;t think "gee this sounds crummy."

But music requires a full range of sound. SO your speakers could have shredded woofers and still sound OK for voice. SO we test the speakers, but also test the system. The speakers could be perfectly good, and are faithfully producing crummy sound coming from the system. So we test each part.


The equipment looks good enough for a small PA, but the speakers have only a 12" woofer, so there is a limit to how much bottom end it can produce - especially outdoors. Outdoors is the toughest room to fill with sound. Your system looks good for basicsd, but one addition that Might help would be a graphic equalizer between mixer and amp. That would let you fine tune the overall tonal structure.

How is the mixer being set up for the music channel? You have three-band EQ on each channel, so if your sound is boomy, make sure the EQ on the music channel does not have the LOW control cranked up.

The CD is a stereo signal, so are you going into the Tapco through channel 5/6 or 7/8? Those are set up to receive stereo signals. You could also use two channel in the 1 through 4 group. There is also the CD input jacks, but honestly I don;t recommend using them for use in the PA mix, I use them mainly as a way to listen to something - like while learning a song. Much prefer using 5/6 or 7/8 for CD.
Enzo, thanks so much for quickly responding. You've given me a great action plan to try to figure this out.

I think the first thing to rule out is the speakers. I just need to find someone who has speakers we can use.

The Sony CD player is just a typical home stereo type unit with the two RCA jacks. These are terminating into a 2-to-1 plug adapter into channel 2 of the Tapco. I did move them into the CD input jacks and there wasn't any improvement. Adjusting the three band eqs had no effect. Unfortunately the Samson only has XLR type input connections. Do they make RCA -> XLR adapters? We will definitely try another source.

Do you have any recommendations for the equalizer between the mixer and amp?
  Reply With Quote
Old 31st August 2012, 02:50 PM   #5
diyAudio Member
 
Join Date: Aug 2012
Forgot to ask, if the woofer is shredded, can it be replaced with an aftermarket, like a Dayton PA310-8?
  Reply With Quote
Old 31st August 2012, 04:00 PM   #6
diyAudio Member
 
chrispenycate's Avatar
 
Join Date: Aug 2006
Location: Geneva, Switzerland
Silly question, but how old are the speakers? I've got a pair of EV 12" where, after abou thirty years of good and loyal service the foam surrounds just disintegrated; I'm planning to have them reconed soon. Not overuse, or too much power; just the foam itself having a limited lifetime (unfortunately, the guy who claimed a "lifetime guarantee" on the products when I first got them in the seventies was obviously talking about his own lifetime, not mine; he died the year before).

But if this is the case, all EV professional products I've met can be repaired, not just thrown away.
  Reply With Quote
Old 2nd September 2012, 02:20 AM   #7
imix500 is offline imix500  United States
Proud Union Member
diyAudio Member
 
imix500's Avatar
 
Join Date: Mar 2004
Location: Nashville, TN
I agree, the replacement woofers are not that expensive if you can find a local place that will sell them at a discount or you could get them online. The sX300 really isn't a bad speaker and can take a fair bit of abuse, but any equipment operating outdoors is subject to extreme duty.
Without seeing how they are deployed, you might consider adding another pair of the 300's and adding another amp or upgrading the Samson to drive all of them to even the coverage in the stands. Or you could just put a couple of Danleys boxes at the scoreboard and call it good.
  Reply With Quote
Old 2nd September 2012, 03:01 AM   #8
diyAudio Member
 
Ferrit37's Avatar
 
Join Date: Apr 2007
Hey Guys,
The original post said that speech was okay, so maybe it's the sony cd player and the Tapco mixer aren't matched, line level/mic level ?
maybe turning the input gain down, if its overloaded, might help or if theres no line input inserting a pad on the line.
__________________
Warmest regards,
Ferrit37
  Reply With Quote
Old 2nd September 2012, 12:37 PM   #9
diyAudio Member
 
Join Date: Nov 2002
Quote:
Originally Posted by stilinsm View Post
Hello everyone, hopefully someone can point me in the right direction.

My daughter's high school football stadium PA system just sounds horrible. She's in her senior year and for 4 years I've sat in the stands listening to people complain how bad the system sounds. So I decided enough is enough and trying to do something about it. It's a relatively small stadium setting, probably around 1000-1500 people.

The vocal sound from the microphone sounds ok, but when they play music, the speakers sound blown, with way too much bass and zero clarity.

So before I break down and start spending way to much money for new speakers, I was hoping for some advise on how to troubleshoot.

The system consists of a pair of EV sx300 outdoor speakers, a Samson sx 1200 amplifier, with a Tapco Mix 220fx mixer which a Sony CD player and announcers microphone plugs into. The Tapco plugs into the Samson with XLR connectors. The speakers plug into the Samson with speakon connectors.

Any advise on how to tackle this would be greatly appreciated.
First of all the system is questionable as to its usability. The EV SX300 is a bassy sounding speaker and needs a 31 band EQ in about all installations. They sound muddy at best before eqing and somewhat usable after eqing. Two of them would be pushing the limit in most applications. Generally these speakers suffer from the spider assembly coming unglued and the assembly vibrating and giving a blown sound.

If it were me I would borrow the necessary equipment in which to test the response of the system. You need an pink noise generator and an analyzer as well as a calibrated microphone. You are simply going to put pink noise out and listen to what your getting and based on the response adjust the 31 band EQ and the result will be a system that will sound and perform better.

If the woofers are indeed blown then change them out with EV drivers and not something generic in nature. The box is ported for that specific driver and not something else.

I would be more than happy to GIVE you an Eq if you would pop for shipping. I have several Shure DFR11's and a analog 31 band Eq and you could have your choice.

If you want something better I have a Shure DFR22 which I had in my theatre in my other house that I would sell for $150.00
  Reply With Quote
Old 8th September 2012, 01:51 AM   #10
diyAudio Member
 
Join Date: Jun 2012
I think the horrible spunding speaker deal is a staple of small town football stadiums and basketball courts. I have never been to a game in such venues where the intermission activities or anything but the normal announcer's voice did not sound like a broken tin bucket trying to broadcast an old am mexico radio station, and uber poorly in doing it! That siad I too have offered many time in the past to please please let me mess with to the point of please just let me buy you guys something so that I can escape that terrible sound! type of deals, to no availe here anyways. I hope you have much better luck!
If those speakers are mounted outside and have any length of service time on them you can just about be assured they are blown, there are dirt dabbers wasps nests inside the horns and maybe even on the woofers and that if the cones are even partially intact the surrounds have long since left the building with Elvis, allowing the cones to wonder around freely at volume levels usable for music, in which the voice coils of course will be shorting out. Find some speakers, hook them up direct inside the annpouncer booth, ensure the pre-amp, eq etc is set close to properly ( not too high on the pre or initial gain settings or too low allowing for an bad attemnpt at the chisled sound of Jimi-Hendrix Marshall amps..and go from there. find that usually the pre amp (or whatever they are using for such) is turned way up highe than the amp creating horrible distortion, speakers are always blown in one way or another (face it there is a reason they make outdoor type speakers, even they need cleaned and checked routinely!) and thirdly the actual amplifier is one made for voice only amplification, such as the many P/A amps or multiple channel mics amps (high gain and usually not connected correctly)..try finding a local band guy or d/j, any inquires with music companies generally lead to a total sales pitch for their stuff, with-out truely identifying the problem. and yes sometimes there is a simple fix, rare but it can and does happen. Generally I have found most of these systems being installed by electricians who do the lighting for the venues, and no, even tho some do adapt them, those old university or radio shack bullhorn looking loudspeakers definately were never made to reproduce with clarity any for of musical sound, they are meant for vocal announcement type use only, and sound like it too!.
Good Luck if I can help feel free to ask. I ended up buying 4 peavey SP-2x's and building boxes for them (screens and wather proofing as best as possible) and mounting them on top of the announcer's booth at the football field, one used Electro-Voice 2600 amp and a cheap ebay purchased 4 channel mixer is used as a pre-amp....clearly marking the para-eq dials to the best settings for announcer's vocals and the best settings for playing music, and even then later setting two channels for announcers and two for music and removing the dial knobs completely to ensure they were not adjusted by some would/be wanna/be sound tech ( or w/e). SOunds pretty great, clear and loud, covers the entire field at respectable DB, npo not concert levels by any means but loud enough to make the older Gen squint and at times complain, usually that means just right, right?..total cost, 780$, a couple days of shopping on ebay and a couple hours directing highschool kids where I wanted them to set the speakers up with. The enclosed boxes I made from things around my shop, but that all could have been bought for less than 100 bucks too.
Good Luck, let us ll know what you end up with!.oh.beware of wasp nests when messing around old outdoor installs, happens everytime!
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Portable PA system renzuken101 PA Systems 14 4th November 2011 02:50 AM
PA sound system metaverse Subwoofers 46 7th October 2008 05:27 PM
PA system got me down.... xstephanx Multi-Way 27 28th April 2006 12:46 AM
2 way + sub PA system: what power for each way? Bricolo Everything Else 1 29th June 2004 01:57 PM


New To Site? Need Help?

All times are GMT. The time now is 03:08 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2