DI Boxes

(Video transcript) Hi. Paul Donovan here from AVTechnician.ca Thanks for watching my channel. This is the channel where we're giving tips and tricks to AV technicians and those who would like to be an AV Technician.

Today my topic is DI boxes. Direct Input or Direct Interface is what that means. In the AV world we will use this device to convert a signal coming from, say, an instrument such as a digital keyboard, a guitar, bass guitar and converting so it can go to the mixer board. One of the things that happens when you are getting a signal from an instrument you're getting through a cable like this with a 1/4" plug. If you look closely you will notice that that is only a single mono jack. That tends to be an unbalanced signal and it tends to also create a fair bit of potential for noise. and interference. What we want to do is we want to convert the signal that's coming from the instrument to an XLR As we do that we most likely will use a device such as a DI box.

This is my DI box and I'll tell you more about it in a few minutes. There such a variety of DI boxes some of the pictures I'll show will just show you the magnitude of how many types there are. What you've got coming into the DI box is a high-impedence sound coming off the instrument, guitar or piano, even a computer interface. These are high impedance and they tend to be much more powerful than what the mixer board is prepared to receive. You want to use a DI box to convert to a balanced XLR connection. Then when you have a balanced signal running through the XLR you can run a greater distance to the mixer. This will help reduce the loss of signal and also help protect the frequencies that are coming off of the instrument.

There are two types of DI boxes. The "passive" and the "active" type. The passive type is not the one I showed you, more like the one in the picture The passive have absolutely no power. No battery, no nothing. All they do is convert the high impedance signal to a low impedance signal. The cheaper ones are very simple, that's all they do. The little more pricey ones will add in a button to do ground lift issues, in case you are having any grounding within the cabling. Then up to the higher end ones that allows you to pad the signal and some will have an inverter switch. Helps further clean up the signal. All of this done without any power. All its using the power that is coming from the high impedance, low impedance, that little tiny power is all that is driving the signal.

The other kind, like my own, is an active DI box. An active DI box probably contains some form of power. In the case of mine it's got a 9-volt battery. You get additional processing capabilities. On my box there are two 1/4" input jacks and two XLR jacks. Through the combination of these buttons you have the ability to take a single feed split it out stereo. You can keep it separated out so each of these feeds are separate into two channels. Or you can even have a stereo feed, say from two instruments coming from a laptop with a stereo feed or some digital keyboards fire out a separate feeds for left and right. Then you can run it back to your mixer board on XLR cable and left/right control at the board. This one also has a pad control. A link to linking the two jacks together, or keeping them separate two channels. It has a ground lift button and it has the battery that turns the power on. It's got a little red light. This is an active DI box. It's probably one of the lower end cheaper ones. I've had a good luck with this thing especially the use of the stereo feature.

One of the common features we see happen a lot is when you've got your laptop output coming out of a jack such as this and you're taking these -- if your laptop is next to the mixer board you could just plug this straight into your mixer board, into the line inputs but what I often do with mine is I will plug them both in keeping the two tracks then each of these feeds go out to the mixer board so I maintain left/right or stereo feed to the mixer board so that I can continue to split it out. Really handy if you're trying to do something where you have a left and a right channel.

Likewise you can do the same is you could have just single jack for your piano and then the other jack could be for your guitar. Then two feeds going to your mixer. This is an active DI box. Really handy this one is made by Behringer. I didn't pay a heck of a lot of money for it. It's paid for itself many times over.

Because this one is on the lower end doesn't not have a pass-thru jack. Some of the cheaper passive ones you have the input where you put your instrument in and then another jack that is an output. The signal has not been adjusted. This is just passing the signal from the guitar or the instrument pass back out again so it can be connected up to the amplifier that might be on stage. This is almost a necessity because not a lot of guitar amps have an output that you hook to the mixer. This way you take your through-put put your instrument in the input and the other jack run another cable to the amplifier on stage. This DI box it does not have a thru jack. A lot of the cheaper/passive ones do.

That's a DI box, just a little bit of information. We recommend you use this whenever you are planning a long distance run from your stage to the mixer -- through your snake, maybe. Wanting to keep the quality of your sound coming from your piano and your instruments a clean as possible.

This is Paul Donovan from avtechnician.ca Please check out our website at www.avtechnician.ca. Subscribe to this channel to keep up with what's happening in the world of AV technicians. Thank you for watching.

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