formats

Why you should tune your stage monitors in the venue prior to an event

Let’s assume there is a stage full of floor wedges that are being provided by a rental company. Shy of verifying them with a measurement rig, there is no reason to assume the wedges are all functional much less able to provide a flat frequency response just because they came out of a truck. In fact the chances of them providing a flat frequency response is almost zero. Here are a few scenarios I’ve run into over the years.

1. The local has his / her favorite settings to make the monitor sound good which could mean anything.
2. No one has any opinion at all and maybe doesn’t even care. After all, “it does makes sound.”
3. You’ve been provided with a really nice monitor rig that is well maintained and the local has tuned them for you (and not with his voice).

The first time I actually made the time to measure all the stage wedges provided for my show was an eye opener. I was provided with “custom” 2 way active boxes. By measuring each box individually, I found some frightening things. In some cases the woofer & horn were out of polarity leaving a huge hole in the frequency response through out the crossover range. I also discovered extreme imbalances between woofer & horn due to the amp settings which by the way changes the crossover frequency. I also found one wedge that only produced highs because the speakon connections were loose. It was on this specific gig that I decided to purchase Smaart 7. Specifically for it’s LIVE IR function.

This might be a rare case but my guess is that any sound company that is providing “custom” active stage monitors that doesn’t own a measurement rig (and know how to use it) is providing inferior gear and service. At one time in history, all stage monitors were “custom” made. Fortunately the industry matured and we now have some very good sounding and well processed options. This isn’t to say that they don’t need to be verified and tuned. I speaker with a perfectly flat response won’t be perfectly flat anymore if it’s near a wall or near a corner of a room (a typical situation on a small club stage). If you use 2 wedges as a pair (typical), you will have severe comb filtering across most of the frequency range unless you aim those speakers correctly to avoid it. Even so, you can expect the low end of a wedge pair to be enhanced and expect to need some low end reduction in order to provide a flat frequency response to the user. Many monitor engineers use their 31 band graphic EQ to “shape” or “correct” the response of a wedge but I would strongly argue that is the wrong approach. Stage monitors should be processed for a flat frequency response (just as a sound system should be) leaving the 31 band graphic EQ flat. This allows for quick adjustment of the mix if necessary. If you use the graphic eq to shape the response of a stage monitor, you’ve already hacked things up before the artist arrives.

For years I saw band riders that said, “no passive wedges, all wedges must be active 2 way with 2″ HF driver.” In theory,

In my view, unless you’re provided with a self powered wedge, you’re better off with a well designed passive wedge than an unknown active wedge. Whether you’re designing a passive or active wedge (or any speaker for that matter) you have to select the right drivers, build a box that those drivers are happy in and then optimize how those drivers interact and work together. Get it right and you’ve got a marvelous thing. Get it wrong and no amount of EQ will solve the issues. With a passive wedge designed by a reputable company, there isn’t much to go wrong. You can damage the driver / drivers by using too many or too little watts but otherwise it will just work. Once you move into the active realm, there are a dozen or more things to go wrong. One of the mistakes I’ve seen made on active stage monitor rigs more than once is to adjust the balance between the lows and the highs using the amp channels. To be clear, there is a right and wrong way to adjust the response of an active speaker and it shouldn’t be done at the amps once the speaker has been correctly configured. How? With a measurement rig. A measurement rig will help make important decisions like the crossover frequency, balance between lows and high and the general shaping of the speaker. Once all that is done correctly, it’s a safe bet that the wedge will sound good AS IS and whatever might need to be adjusted will be easily managed with the industry standard 31 band graphic eq provided on pretty much every monitor rig in the modern world. If you get the crossover / balance between drivers and processing wrong, there is little chance the graphic eq will be able to solve the issues.

Questions:

How do you choose the appropriate cross over frequency?
How do you choose the correct amp / amps to power a passive or active speaker?
How do you process a speaker in such a way that it has a flat frequency response on the floor?