Transcript
Understanding the Driverack 260 First, let’s look at the main Program screen.
This picture shows the Preset # and name for the currently selected preset. If “Not Loaded!” is displayed at the bottom of the diplay, the ENCODER must be pressed in to load the currently selected program.
This screenshot shows the inputs and outputs of the program screen.
Here is a breakdown of the components in the Driverack 260.
If at anytime you want to come back to this main program screen just press the PROGRAM button. Think of it as a kind of “Panic” button.
The below screenshot is a typo in the manual. This is actually a screenshot from the Driverack PA and will never be displayed in the Driverack 260.
Configuration Mode The Driverack 260 has a CONFIGURATION mode that enables you to go in and change the internal routing of the signal, link/unlink processors and select different processing blocks. This gives you much more control and many more configuration options over the Driverack PA.
In order to perform the below procedures, it is recommended that you familiarize yourself with the navigation of the Driverack 260. Please see the owners manual for more information on navigation.
When setting up your system the procedure order is as follows: 1. Set the x-over points, slopes, driver alignment delays and post x-over PEQs (optimizes your speakers, but doesn't take the room into account). These are usually available from the speaker manufacturer. If your speakers were selected in the WIZARD these settings will be set for you automatically (do not go back into the x-over and change these settings if you are unsure of what you are doing). If you use passive (full range) speaker cabinets you shouldn’t have to worry about any PEQ settings, but you may want to set a high pass and possibly a low pass filter if needed (look at the frequency response of the speakers). 2. Set the gain structure (optimizes your signal to noise ratio and helps prevent clipping). This includes setting the gain of each device (in this case the Driverack and amps) and the output limiters. If you selected your amps in the WIZARD, the x-over (output) gains and limiters will automatically be set. Do not go back into the X-over or Limiter and change the settings if you are unsure of what you are doing. 3. EQ the system (tune your system to the room). Use the Auto EQ function to tune the system to the room. Some fine tuning will likely be needed. Fine tune gain structure to take the EQ gain into account. 4. Ring out the system using the AFS (feedback suppression) to eliminate feedback. 5. Add extras to desired taste. This includes the Subharmonic Synth, compression, etc.
1. X-OVER & PEQs If you selected your speakers in the Setup Wizard, the Driverack will automatically set your x-over parameters, driver alignment delays and PEQs. If your speakers are not in the Wizard, you should select “Custom”. You will need to obtain the recommended x-over settings (and other speaker tuning info, if available) from the speaker manufacturer. There are some tuning programs available for download. Please check the dbxpro website to see if your tunings are available for download. You will have to use the provided Driveware software to load these programs into the 260. If you use passive (full range) speaker cabinets you shouldn’t have to worry about any PEQ settings. If the subs are not lined up with the mains, driver alignment delay may be needed.
2. GAIN STRUCTURE & LIMITER By properly setting the gain structure, your signal to noise ratio will be optimized (your system will be as quiet as possible) and you can minimize the possibility of clipping any components in your system. Make sure that your amplifiers are properly rated for your speakers before proceeding. If you are unsure, contact the speaker manufacturer. If you selected your amps in the Wizard this has already been set for you. If not, please proceed. Make sure to select “Custom” for your amps when you run the SETUP WIZARD. Make sure that all the dynamics processors (limiters and compressors) and the graphic EQ are off before proceeding. Unplug your speakers from your amps. Most solid state amplifiers will not be damaged when operated without a load connected. If you are unsure, contact the amplifier manufacturer. Keep in mind that the amp may clip slightly sooner when the load is connected, so make sure to leave a “cushion” of headroom. If possible you can use a dummy load to get a more accurate reading. Make sure that your output limiters are off before proceeding. Run pink noise through your mixer (from a cd or generator). Set your CD (pink noise source) channel to unity gain. Bring up the master faders on the mixer until you barely clip the mixer. If you can’t clip it, bring up the channel fader. If you still can’t clip the master section, try raising the gain or trim pot slightly. Now adjust your mixer to just under the clip point. Now adjust the inputs of the next device (for the sake of this document, this will be the 260) until you are just below the clip point. If your amplifiers have a voltage sensitivity switch, set them to around 1.4 Volts. Now, select one of your amps to start with and set the attenuator so that it just clips, then back it off so that the clip indicator just goes out. Now lower it slightly to provide a little extra room to compensate for there being no load connected. Mark this setting with a piece of tape or something that will not permanently mark the amp. Now turn the amp attenuator up until the clip indicator just lights again. Go into the Limiter, for the outputs that you are currently working with, and turn it on. Set the Overeasy setting to “off”. Set the limiter Threshold so that you no longer clip the inputs of the amp. Now set the attenuator back to the mark that you made earlier. Repeat this process for all other amp channels in the system. Turn your mixer down and your amps off. Reconnect your speakers, turn your amps back on and try running some music through your speakers. You should not be continually hitting the limiter when you are running your system at performance level, which should be unity gain (0 VU on your mixer). If you do, go back and redo the gain structure process. The limiters should only be triggered by the peaks. You will want to then adjust the attenuators to achieve as flat of a frequency response as possible before you run the Auto EQ. Make sure that you turn down attenuators (you don't want to set the attenuators past the mark that you made earlier). So for example: If you don't have enough low end, turn down your mid and or high amps. If you are using powered speakers you will need to know what the maximum input of the powered speaker is. The maximum output of the Driverack PA is 20 dBu (about 7.75 Volts).You would have to find out how much attenuation is needed on the amp/speaker so that an input of about 7.75 Volts (20 dBu) would be just under the clip point of the amp.
3. GRAPHIC EQ If you have the optional RTA microphone, you can use it to tune the system to the venue. If you have set the gain structure properly, when your system is at unity gain throughout, you will also be at the desired performance level. So, this means when you run the AutoEQ, you should reach the desired performance level when the Driverack 260s output levels are around 0 to +5 dBu (they may be slightly below this due to x-over and speaker tuning settings). Just make sure that the outputs aren’t really high before running the AutoEQ function. You need to leave some headroom available for the EQ to make it’s adjustments. Microphone placement can be a big issue. If running both sides at once, place the mic out approximately the same distance as the speakers are apart. Place it so the distance between the mic and either speaker is the same. You don’t want there to be a time delay (one speaker being further from the mic than the other). You could also try placing the reference mic directly on the floor. This can have a big effect on frequencies near 250Hz. You may want to try running the pink noise out of only one side, so that you are not trying to compensate for the comb filtering effects of the two speakers combined. There are a few different response curves in the Auto EQ. Usually, response 0 (flat) is a good place to start, but may require some fine tuning. If you plan on running your system at loud levels, you will want the response to be more flat. If you are running the system at lower levels, you may want to use one of the other response curves that contain a low and high boost. You may want to set the lower frequencies (from about 100 Hz down) closer to flat after the Auto EQ completes. This is usually a better choice because EQing these lower frequencies are going to affect other listening positions in the room anyway. Unfortunately, you cannot make every listening position in the venue have the same low frequency response. Since you cannot EQ non minimum phase problems, any bands that are boosted or cut more than 6 dB should be brought back closer to 0 dB. You may want to fine tune the higher frequencies by ear. There is a natural high frequency roll-off that occurs as the distance from the source (speaker) increases. If you boost the high frequency bands too much, you run the risk of distorting your high frequency drivers (running out of headroom) and/or deafening the people in the front row. You may want to experiment with the other response curves to see what sounds best with your style of music and at different system levels. However, typically you want your speaker system to not introduce its own color on the sound, so a response setting of “0” is usually a better choice for live sound. You will need to experiment to find what works best for your application. A precision setting of “LOW” will finish the fastest, but will not be as accurate as a “HIGH” setting. Sometimes a setting of “MEDIUM” or “HIGH” may take a long time or never finish because the acoustic environment may be too complex or ambient noise may be impeding the process. The “LOW” setting should be acceptable for most applications and will get you up and running the fastest. The LOW setting also has convergence criterion that allows more bands to be off. Use this settings if the Auto EQ does not finish or you want a first cut of the EQ. You can always "freshen up" the eq settings with a subsequent Auto EQ procedure - it will pick up where it left off. There can be many circumstances where the AutoEQ will not work. AutoEQ can only fix the problems that EQ can fix - if there are speaker placement, gain structure, xover, speaker presets, time alignment issues etc, AutoEQ will not be able to tune the
system. If AutoEQ is not consistently converging, look at the rest of the system - there may be issues with the setup that Auto EQ can not address. AutoEQ does best when it only has to compensate for room resonance. Tuning your speakers is best done with the x-over/PEQ/alignment delay. If the display reads "not done", take a look at the EQ settings after you have run the Auto EQ. It will tell you which frequency region you are having problems with. If it's around the x-over point, then you have most likely improperly set the x-over settings. If the problems are in the lower frequencies, it could be caused from room modes or lack of low frequency response in your system. If it is the high frequencies it could be that the mic is placed too far away and trying to boost the extreme high frequencies (the Driverack PA cannot take a systems natural high frequency roll-off into account). If you do not have the optional RTA microphone, you will have to go into the GEQ and fine tune the system manually by ear using a music CD that reproduces all frequencies that your system is capable of reproducing. You will most likely need to fine tune the gain structure to compensate for any EQ adjustments. Keep in mind that you do not want to alter the overall balance between the low, mid and high drivers.
4. AFS FEEDBACK SUPRESSOR Run the AFS Wizard to ring out the system and achieve more gain before feedback. There are two modes or types of filters in the AFS. These filter types are FIXED and LIVE. Keep in mind that it is very important for the systems gain structure to be properly set for the AFS to function properly. The FIXED filters are used as permanent notch filters and the LIVE filters will be lifted if one of the below conditions are met: 1. Expiration of a period of time that is pre determined by the user (LIVE filter lift setting). 2. All filters are used and begin to round robin (lifts the first LIVE filter set to use it at another frequency location). Chances are if this problem persists and begins to loop, then you need to turn down the gain at your mixer. 3. The unit is power cycled. You will want to do a quick sound check on the microphones first. Get them as close to the desired performance level as possible before feedback occurs. Make sure to use proper gain structure techniques for adjusting the individual mixer channels. You can start with 6 FIXED and 6 LIVE filters. Select the desired notch filter size. The selections range from SPEECH, which have the broadest Q factor to MUSIC HIGH, which have the narrowest Q factor. Speech will be the most audible and may not use as many filters to eliminate the feedback. Music High is the most inaudible, but may use the filters up faster. You will have to find a happy medium when selecting the width of the filters. Now with no signal going to the mics, but with the mics active, slowly bring up the master fader(s) on your mixer until you reach the desired performance level (probably around 0dB on your mixer’s master fader, assuming your gain structure is set properly). You may want to push the master fader(s) slightly above 0 VU so that you are not right on the verge of feedback when set to unity gain. If you run out of FIXED filters, go back and allocate more filters as FIXED and repeat the process. If you still can’t eliminate the feedback and don’t have many more FIXED filters to set, try setting the filters to a broader Q (such as Music Low). If you don’t use all of the FIXED filters, you can go back and designate more of the filters for LIVE and repeat the process. Once you are done the unit will automatically enter LIVE mode.
