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  • PA question

    When running through a PA system what levels should I have the mixer and power amp at so I don't damage the speakers or amp? Should I max out the TD-8 and mixer volume and then go up on the power amp? Or should I go about 75% on the TD-8 and mixer and go up on the amp from there? Thanks for your experience.

  • #2
    As long as your speakers are not distorting and your clip light is not fixated you will be ok at what ever level you have your settings.

    You really want to set your amp’s output to a good strong level with headroom in case you want to push it. Then use your mixer to control your PA output. The mixer should never be pushed to the max; your mixer should not be clipping either.

    On the TD-8, the levels should be set to what ever seems good to you. Personally I keep my levels (on the faders) all the way up and control the gain individually for each instrument per kit within the TD-8’s mixer. I would also recommend keeping the kicks channel on the outboard mixer a bit higher then the rest of the TD-8’s sounds – hats, snare, toms, cymbals, etc. This way you can bring out some of less hard-hitting kicks and you can always turn down the harder kicks internally.

    Your ears will tell you what is right and what is not, when you get your PA fired up.

    What does your PA consist off? Is your impedence matched up well with your AMP and speakers? What is the power you are able to generate?




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    szvook
    Studio

    Comment


    • #3
      I already run my TD-8 like you described with the faders maxed and the internal mixer tweaked. My PA is 2 dual 15" speaker cabs with horns, 1000 watt power amp and an 8 channel mixer. I'm not getting clipping on either the power amp or mixer but I haven't needed to push the PA for more than house parties. I was wondering If someday I need to push it should I max out the power amp and then move the mixer levels up? What is impedence?

      Comment


      • #4
        I have pushed my PA many times (1600 watts continuous program power) and the best way is to turn up your amp first (either max or to your best discretion) and then play with the mixers levels.

        Speakers have an impedence. The speaker impedence is what the amplifier sees as the load. If a speaker is 4 ohms, that is the load at which amplifier sees, so the amps output is at 4 ohms. Most amplifiers run best at 4 ohms. Some are stable at 2 ohms but for
        longevity and to avoid overheating 4 or 8 is best.

        Impedance of a speaker will change with frequency. The better the speaker (generally) the less the nominal impedance will change in any given situation.


        What ohms are your speakers and your amp?


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        szvook

        [This message has been edited by szvook (edited May 08, 2001).]
        Studio

        Comment


        • #5
          Originally posted by ADD:
          What is impedence?
          Impedance : (Z) Measured in ohms, it is the total opposition to the flow of current (I) offered by a circuit. Impedance consists of the vector sum of resistance (R) and reactance (X).


          Impedance Matching : Matching the output impedance of a source to the input impedance of a load to attain maximum power transfer.

          ... or what svook said is good.

          -----------------
          -~

          Comment


          • #6
            I'm pretty sure they are running at 4 ohms.
            I will check for sure tonight.

            Comment


            • #7
              More info......


              Impedance - What does the term impedance mean? Impedance is a way of measuring how much a speaker "impedes" or resists the flow of electricity (watts) coming from your power amplifier. Oddly enough, the lower the impedance rating, the harder the amplifier has to work. Most professional speaker systems have nominal impedance rating of 8 Ohms. Ohm (symbolized by the Greek letter omega) is the actual unit of measure used to state impedance values. As you add more and more speakers to your system, the total impedance will get lower and lower and burden your amplifier until it goes into a protection status mode or blows up!
              Be careful how many speakers you hook up to your amplifier:
              If you plug two 8 Ohm speakers into one channel of an amp, the together changes total impedance will be 4 Ohms. If your amp is stereo (meaning it has 2 independent channels) and you plug only one speaker into each channel, the impedance will be 8 Ohms per channel.
              If you hook up two more speakers to your stereo amp, one to each channel you will now have an impedance of 4 Ohms per channel. This is probably fine for most stereo power amplifiers. However, you should refer to the amplifier owner’s manual for specific impedance information. This specification is usually stated as the "minimum load impedance". It might say "4 Ohm load minimum" per channel. If you do not have the owner’s manual for your amp, contact your dealer or the manufacturer directly and ask for one.
              Remember, using standard speaker cables, impedance adds up like this:
              Two 8 ohm speakers plugged together=4 Ohms
              Four 8 ohm speakers plugged together=2 Ohms.
              If an amp is rated for a "2 Ohm load minimum per channel", that means it will drive four, 8 Ohm speakers per channel or eight speakers total. Because there is less impedance to the power amp’s output section, it is capable of putting out more power, which makes it work harder and run hotter. The extra together changes power being delivered to your speakers will be divided equally among them so be careful that all of them are capable of handling the same power levels. The general rule is: the more speakers, the lower the impedance.


              Never can speakers be too powerful for an amp. The amp may not put out enough power to get the best and fullest performance out of the speakers but the speakers cannot over power the amp. The only way you can overload an amp with speakers is if you run too many speakers off one amp such that the ohms load is less than the amp can handle, say four 8 ohm speakers giving a 2 ohm load on an amp that is only designed for 4 ohms.

              Another huge point. Many people erroneously think their 500 watt amp is always putting out 500 watts and thus fear that they could blow up their 100 w speakers. Well true, they could but don't have to. They could happily drive even 50 watt speakers for years with no blow out UNLESS the owner cranks up the volume to the full power output capability of the amp. Then sit back and watch the cones flap. It's a misunderstood point. The power output of an amp varies with volume level- when there is no sound the amp is producing zero watts. When the volume is low the amp is putting out only part of its potential. As the volume is increased, the amplifier power output increases. Mono- bridging is a way to get more power out of your amp. With two 8 ohm speakers, you can get 290 watts into each speaker in stereo or nearly 600 watts into each speaker mono bridged. You got to read the spec sheet. Not all amps can be mono-bridged

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              szvook

              [This message has been edited by szvook (edited May 08, 2001).]

              [This message has been edited by szvook (edited May 08, 2001).]

              [This message has been edited by szvook (edited May 08, 2001).]

              [This message has been edited by szvook (edited May 08, 2001).]
              Studio

              Comment


              • #8
                Zt = Z1 x Z2 / Z1 + Z2

                (8 x 8 = 64) / (8 + 8 = 16) = 4 ohms

                a shortcut is if you are using all the same impedance speakers, divide the imp. of 1 speaker by the total number of speakers.

                8 ohms / 2 speakers = 4 ohms

                Comment


                • #9
                  Svook, man....what the fu*k.

                  I'm hiring you as my sound guy when I'm famous.


                  I never understood any of that (and, being a drummer, never really needed to). I'm not sure I fully understand it now, but I'm glad I have more of a clue. Thanks.

                  BINARY

                  Comment


                  • #10
                    Here's some more info on pa systems. Check the efficiency of your speaker cabinets. Generally, cabinets with two 15s and a horn are about 102/3 at 1w/m. That's pretty efficient. If your power amp says it is 1000 watts, it's probably rated at 1000 watts at 4 ohms bridged. This translates into about 350 watts per speaker cab at 4 ohms. Together with an efficiency of 102/3, this will give you adequate power for most small to medium places. Keep in mind that going through the passive crossovers in you speaker cabs will cost you approximately 10% of your power.

                    I agree with Sz, turn your amp up first . I almost always turn the power amps wide open. This will allow the transients/dynamics of the music to be fully reproduced at the power level you're using.

                    There are some things you can also check for to help with more clean power/volume. If your amp and speaker cabs have speakon connections, get two 14 gauge speaker cords. This will give an immediate boost in power and clarity, though not earth-shaking, assuming you are using normal 16 gauge 1/4" speaker cords. Make sure your speaker cords are the same length. Try to run the shortest speaker cords you can. Try not to run over 50' feet in each direction.

                    If you do as many of these as you can and start playing places where you need more clean power, beg, borrow, steal, but find a way to get a Mackie sub. It's extremely easy to interface into any pa system and it will give you loads of kick and bass that you didn't hear before, without the complexity of another amp, crossover, etc. You're big cabs will last many more years and they will be capable of getting seriously loud, cleanly.

                    Sorry this was so long. I tried to keep it short. Hope I didn't confuse you. You can e-mail me if you need more info. Hope it helped.

                    Jay
                    jg52

                    Comment


                    • #11
                      Originally posted by BINARY:
                      Svook, man....what the fu*k.

                      I'm hiring you as my sound guy when I'm famous.


                      I never understood any of that (and, being a drummer, never really needed to). I'm not sure I fully understand it now, but I'm glad I have more of a clue. Thanks.

                      BINARY

                      To be honest, I was really hesitant to drop that kind of info – I didn’t want to make people feel uncertain about their needs for a good match up in the PA. But since we are dealing with electronic drums, the need for a proper PA is as vital as the drum modules of choice that we decide to use. After all, the signal output through speakers will be the final judgment of your module and it’s sounds and that needs to be factored in on the highest level.

                      Simply put – only a proper match up in the amp & speaker can make the edrums sound right and a wrong match up could make the edrums sound like…lets say less promising; which could lead some to believe that the module is not all that and unnecessary tweaking to the module could follow.

                      The last step is the most important and crucial !!!!!


                      PS: Can I also get famous first? Then I will be free and I will take you up on the offer




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                      szvook
                      Studio

                      Comment


                      • #12
                        Originally posted by szvook:
                        ... the flow of electricity (watts) coming from ...
                        Correct me if I'm wrong but, I thought the flow of electricity is known as current and current is measured in ampres.

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                        -~

                        Comment


                        • #13
                          Originally posted by Marc.:
                          Correct me if I'm wrong but, I thought the flow of electricity is known as current and current is measured in ampres.

                          Just lingo

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                          szvook
                          Studio

                          Comment


                          • #14
                            Can I ask A Question?

                            How are you guys sending your stuff out to the p.a. and the amp?Are you using the outputs to send everything or are you using the headphones out to your amp?(monitor)
                            I have seen a couple of people in here that do that,And I didn't think you could.Am i missing something here?

                            Comment


                            • #15
                              Everything is going through my Mackie board; the outs from my TD-8 and my amp/speakers – and that is the way it should be. Unless you don’t have an external mixer and then you are cutting your self-short.

                              How are you doing it, just straight from the module?




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                              szvook
                              Studio

                              Comment

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