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  • Doing A System Install - Requesting Comments

    An elementary school has asked me to spec out a sound system for their multi-purpose room (gym/lunch/stage). The Parent Teacher Organization will be buying the equipment directly and then I will do the installation for free. I am an Electronics Tech and routinely do repairs on this type of equipment, but designing installations is out of my area of expertise.

    I was hoping to get some input from the pro sound folks here before submitting my proposal to the PTO.

    The room is approximately 55 by 45 feet with about a 20 foot high ceiling. There is no sound treatment on the walls, but the acoustics are not as "bright" as might be expected in this type of room. Maybe the rough brick is killing some of the brightness? The sound system will be used for stage shows, dances, and movies.

    The Room:



    This is the system that I propose to install:

    (2) Electro-Voice TX1152 Tour X 15" 2-Way PA Speakers (One on each side of the stage - wall-mounted, slightly lower than the existing column speakers, and about 5' further away from the stage.)

    (1) Electro-Voice TX1181 Single 18" Subwoofer (On castors and stored under the stage when not required.)
    100 dB sensitivity, 500 watts rms 132 dB maximum SPL "An integrated low pass filter allows the TYX1181 to be connected in parallel with one a TX1152 on a single amplifier channel, eliminating the need
    for additional amplifier channels and processing."

    (3) Shure SM58LC Microphones

    (1) Shure PGX24/SM58 Handheld Wireless System

    (1) Behringer FBQ2496 Feedback Destroyer Pro

    (1) Tascam CD200i Compact Disc Player with iPod dock.

    (1) Crown XLS100 Power Amplifier
    350 watts @ 4 ohms / 215 watts @ 8 ohms per channel . The sub would be on one channel (4 ohm load on that channel) No way to adjust sub output level?

    The school currently has a TOA 900 series mixer/power amp installed. I would like to use this as the mixer.

    Wire, mic cables, mic jacks, speaker mounting hardware, etc. (have an equipment rack already installed)


    ANY comments or suggestions on this project would be appreciated!

    How about substituting a Dayton RS1202K Dual 12" Subwoofer (kit) in place of the EV sub?
    With the Dayton, the XLS100 should be adequate and there would be a way to adjust the sub level.
    Last edited by myheadhertz; 01-30-2011, 05:27 PM. Reason: change location of photo

  • #2
    Re: Doing A System Install - Requesting Comments

    Edit: I read over the feedback destroyer on your list. Great piece of equipment. I was going to recommend one.

    Comment


    • #3
      Re: Doing A System Install - Requesting Comments

      I wouldn't consider a point source system in a highly reverberant room like a gym. A room like that begs for a line array.
      www.billfitzmaurice.com
      www.billfitzmaurice.info/forum

      Comment


      • #4
        Re: Doing A System Install - Requesting Comments

        Thanks for the reply billfitzmaurice. Could you recommend a line array?
        Something like the TOA HX5B or SR-H3L maybe?

        jcpahman77- Glad to hear you had some good results with the destroyer. I understand you have to really crank up the volume when doing the cals.

        Comment


        • #5
          Re: Doing A System Install - Requesting Comments

          Originally posted by myheadhertz View Post
          Thanks for the reply billfitzmaurice. Could you recommend a line array?
          Something like the TOA HX5B or SR-H3L maybe?

          jcpahman77- Glad to hear you had some good results with the destroyer. I understand you have to really crank up the volume when doing the cals.
          Unfortunately I wasn't the installer in that instance either. It was installed in a youth room at a church I used to run sound for. I was doing the live mix for a farewell show for one of the church's bands. Never had feedback despite the fact that I blew 4 stage monitors on that show (they were old but the point is I had the volume up). Actually at one point the church's head of sound came to check on things -- it was the inaugural run for that system -- his only comment was to ask if I knew that when the main outs on the board hit red it would be 120 db's. I said yes, noting that I was at the last yellow light before red. He didn't say anything after that and the sound never distorted or lost musicality all night. JBL speakers as well FWIW.

          Comment


          • #6
            Re: Doing A System Install - Requesting Comments

            Originally posted by myheadhertz View Post
            ... Could you recommend a line array?
            On the Harman site:
            http://www.harman.com/EN-US/OurCompa...lications.aspx
            is a download by Don Keele called "Effective Performance of Bessel Arrays"
            It describes the performance of this type of line array.
            "Not a Speaker Designer - Not even on the Internet"
            “Pride is your greatest enemy, humility is your greatest friend.”
            "If the freedom of speech is taken away, then dumb and silent we may be led, like sheep to the slaughter."

            Comment


            • #7
              Re: Doing A System Install - Requesting Comments

              Don't know if they are worth it or not, but have you given any thought to referbing the speakers that are there?

              Comment


              • #8
                Re: Doing A System Install - Requesting Comments

                Originally posted by AMC View Post
                Don't know if they are worth it or not, but have you given any thought to referbing the speakers that are there?
                That's worth looking into, perhaps with the addition of subs they might work. Currently most commercial line arrays are either too small, like the TOA loaded with 3" or so drivers, or too big, as in Peavey VersArray etc. The selection of line array cabs was actually better in the '60s. If DIY is an option you might want to keep an eye on this thread:
                http://billfitzmaurice.info/forum/vi...p?f=30&t=14042
                www.billfitzmaurice.com
                www.billfitzmaurice.info/forum

                Comment


                • #9
                  Re: Doing A System Install - Requesting Comments

                  Originally posted by billfitzmaurice View Post
                  That's worth looking into, perhaps with the addition of subs they might work. Currently most commercial line arrays are either too small, like the TOA loaded with 3" or so drivers, or too big, as in Peavey VersArray etc. The selection of line array cabs was actually better in the '60s. If DIY is an option you might want to keep an eye on this thread:
                  http://billfitzmaurice.info/forum/vi...p?f=30&t=14042


                  Rebuilding is a good option and a great idea! Thanks AMC!!!
                  That would leave more money available for subs.
                  Do you think we could get by with the Dayton dual 12" sub? Maybe 2 dual 12's?

                  I'll take the columns down this week and take a peek inside.

                  ...unless we're snowed in, of course. 25" predicted. Tonight, we're running on battery power just to make sure everything is ready for the "big storm". Four hours in and the lights and pellet stove are doing just fine. Usually can go 12 hours on a charge running continuously. Don't have the guts to plug the nice new LG LCD/LED TV into the modified sine wave inverter. LOL

                  Plenty of 12 volt class D audio available, so who needs TV?
                  Using some rebuilt Dahlquist DQM-9's (95dB 1w/1m) powered by a Topping TP21. Sweet! The TP21 is on it's own battery to avoid the inverter hash.

                  Thanks for the linky Bill.

                  Thanks for the linky Sidney. Looks like I've got some reading to do.

                  Comment


                  • #10
                    Re: Doing A System Install - Requesting Comments

                    It doesn't look like there is any downward angle on those column speakers(line array) and that is someting you will have to address if you decide to use them, as mounted they aren't covering anything but the perimiter walls starting at about 10' off the floor.:rolleyes:

                    My automatic reaction is no.. the dayton sub will not be suitable. It may actually produce adequate output but it doesn't have balanced inputs(why haven't they added this yet) and if you want reasonable SPLs in the room I think you'll be pushing it to the limits a lot which isn't good for system durability.
                    A better option IMO would be a sub based around a Pro driver or two simply because it will be able to generate the SPLs needed at something less that it's full rated input power, and that will mean longer life.
                    If you're buying new amplification I'd also suggest getting one with built-in processing to handle crossover duties, a single amp will do with the mains on one channel and the sub on the other, keeping them seperate like this provides better control over the sound.
                    Paul O

                    Comment


                    • #11
                      Re: Doing A System Install - Requesting Comments

                      Take one down, pull it apart, and then lets see what you have. A simple replacement of the drivers with a referbed or replaced x-over might be all that is needed. As far as the subs, the easy way would be to use a conventional powered sub, and just about everyone is making them. You could build one, like a BFM titan or two, but considering your application, I think that a powered unit might be more convenient as you will have multiple people setting up and operating this system. This would not be as nice as a well made and implemented bank of horns, but you must consider the end users here, and active subs will be closer to fool proof.

                      Anyone want to predict whats inside? I'm guessing this is a low budget institutional design, most likely loaded low-mid grade hifi drivers. But sometimes these systems will surprise you.

                      Comment


                      • #12
                        Re: Doing A System Install - Requesting Comments

                        Originally posted by myheadhertz View Post
                        An elementary school ...
                        The room is approximately 55 by 45 feet with about a 20 foot high ceiling. ...The sound system will be used for stage shows, dances, and movies...
                        FWIW RE: Subs - A 32,000 cu ft area ( performing arts school - similar scenario ) uses 2 18's;
                        Your area is 50% larger, but your target SPL may be lower.
                        "Not a Speaker Designer - Not even on the Internet"
                        “Pride is your greatest enemy, humility is your greatest friend.”
                        "If the freedom of speech is taken away, then dumb and silent we may be led, like sheep to the slaughter."

                        Comment


                        • #13
                          Re: Doing A System Install - Requesting Comments

                          Thanks for all the replys and ideas.

                          PaulO: There used to be a second floor upper balcony along the back wall. That's probably why the speakers were positioned high. So, lower and a downward tilt would be better? How about spreading the columns further apart?

                          A "big amp" with built in processing and a couple subs to start. Hmmm... We could then later add more subs if required.

                          Might the original TOA amp work just fine to power rebuilt columns?

                          Comment


                          • #14
                            Re: Doing A System Install - Requesting Comments

                            What is the system going to be used for. For speaking and general playback music the sub woofer would not really be needed and could actually make things worse in a gym...if not properly set up, adjusted. In a multipurpose, multi user system such as what this looks to be the simpler the better.

                            There's a million different speaker concepts to choose from, what you picked would work, mounting them in central cluster above the stage could be something to look at. As for amps look at the XTI Crown Series. With the internal DSP you can set up high pass filtering, EQ and limiting.

                            The TOA mixer uses input modules of various types depending on the kind of input signal you want to connect to a particular input channel. You may need to get some more modules for the mic inputs and the CD player.

                            With some proper EQ no need for the "feedback destroyer".
                            Mike Caldwell
                            http://www.mikecaldwellaudioproductions.com

                            Comment


                            • #15
                              Re: Doing A System Install - Requesting Comments

                              yea, I'd skip the sub. for a dance in a gym you need minimum 600 watts for modest volumes, and that's into pro woofers. the amp you have spec'ed is a little anemic for music duties (bigger amp=less clipping = longer tweeter life) but adequate for speech and general PA. Subs can also be abused, and cheap subs die quickly. you gotta pay to play.

                              speaker choice is fine. hang at an angle. Line Arry would be better but your budget talks, too.

                              go thick on the cabling to keep efficiencies up. there are some long runs here.

                              feedback destroyer... meh... I'd almost say no. go old-school. get a high-res (many band) eq or a parametric, then tune the room either with test tones and a cheap spl meter or buy/rent a RTA. use the eq to knock out the 2-5 main feedback frequencies. add in a compressor/limiter to limit what gets sent to the speakers. Put the limiter, and the EQ, behind a lock. kids and adults think an eq should look like a smile. use white-out to dot the fader positions on the eq.

                              these are classic tools for a fixed install.

                              M

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