Purpose of the DI box?

[JerryHooperMusic]

Would someone please share with me the purpose and benefit of a DI box? Thank you!!

[MRkeys]

Well, I"m not a regular but....

it"s to connect instruments to a mixer. Mostly for long runs down a snake. Converts instrument level to balanced mic level. Usually not necessary for runs under 20 ft

[midinut]

To make the sound man love you. lol

 

No, really it's more of what MRkeys says. That, and in some cases they will add a bit of warmth to your sound, or soul, or special sauce. I use a Radial ProD2 myself.

I feed the line out of my mixer into the ProD2, and the XLR outs to the FOH / Mains / Onstage Snake / Breakout Box (or whatever you prefer to call it). The other

output (thru) I feed to my Personal Monitor Controller for my In-Ear Monitors. They do make the sound man's job easier. Plus they have a ground lift in case you get a 60 cycle hum.

[Groove On]

Keyboards

Almost all keyboards output line-level, so if the mixer has line-level inputs then you don't need a DI, you can plug the keyboard directly into the mixer's line-level inputs. But if the FOH mixer only offers you mic-level inputs, a DI will convert your keyboard's line-level to mic-level. This usually happens at live-music venues because they want all audio inputs to match levels with the microphones of the hosts, singers and other mic'd instruments (e.g. drums/sax etc.). Dropping all inputs to match mic-level is a better/easier than the reverse - bringing all the microphones up to line-level.

 

Guitars

DIs for guitars do the same thing, they drop the guitar output (instrument level / Hi-Z) to mic-level (Low-Z) - so you can plug the guitar into the mic-level inputs on the mixer. Once again if you've got live singers or live mic'd instruments, the DI lets you match levels with the microphones. But if the mixer has instrument-level / Hi-Z inputs then you don't need a DI, you can plug the guitar directly into the mixer's instrument level / Hi-Z inputs.

 

Re: long runs, ground-lift, electrical protection, THRU monitoring

If you want the benefits of using DI - but without changing your keyboard's output to mic-level - look for other devices to fill the gap. For example, unbalanced to balanced converters (-10dBV To +4dBu) and a ground-lift for long runs, some sort of line-isolating transformer for electrical protection and a line-mixer with a THRU for monitoring. A good line-level mixer like the Key Largo has all those electrical goodies plus the ability to output mic-level when needed.

 

For reference:

- In case you're wondering, line-level is the highest signal, followed by instrument level (Hi-Z) and finally the lowest signal, mic-level (Low-Z).

- Keyboards like the Roland RD-2000 have both balanced XLR line-level outs and unbalanced 1/4 line-level outs. On keyboards like the FP-30 or FP-10, maxing the headphone-out volume basically gives you an unbalanced line-level signal. All these keyboard do not need a DI, they can be plugged directly into a mixer's line-level inputs.

[Cabo]

So, I should probably already know the answer to this question (since I own the keyboard) -- but--

 

For running the Roland RD2000 to a snake (and then front of house mixer), could I use XLR outs to directly go into the snake? I had thought the XLR outs could "replace" the need for a direct box. But since they're line level, does that mean I need to use a direct box?

[ABECK]

It's worth using one for the Thru output alone! This signal is for you, Mr. FOH guy. This signal is for me!

If you play or plan to play venues often, it's worth investing in your own rather than rely on the ones they provide. I've seen and heard a lot of suspect DIs that should be taken out into a field and retired.

[ElmerJFudd]

And to clarify - if you"re keyboard has 1/4' instrument outputs - yes, you need DI box to run to PA. However, if the venue"s sound guy doesn"t have a DI box, wtf? Also a good DI box will have a pass through so you can run a 1/4' cable to your amp from there.

 

Some Pro keyboards have XLR outs that are the correct impedance to go straight to PA. Most small firm factor mixers also have the correct output. So if you have either of those, you don"t need DI.

[Reezekeys]

So, I should probably already know the answer to this question (since I own the keyboard) -- but--

 

For running the Roland RD2000 to a snake (and then front of house mixer), could I use XLR outs to directly go into the snake? I had thought the XLR outs could "replace" the need for a direct box. But since they're line level, does that mean I need to use a direct box?

 

No you don't need a DI box. Connect them like you mention â that will work fine. Tell the sound man to expect a line level signal.

[Werno]

One of the main reasons for a DI is to keep your keyboard from being fried if user error connects phantom power from the mixer to your outputs. I have this on good authority from several other times this question has been raised; it was mentioned above amidst lots of other good info, but in case the OP didn't notice it there, I'll risk redundancy. Happy to say I don't know this from personal experience.

[stoken6]

One of the main reasons for a DI is to keep your keyboard from being fried

I was about to post the same thing.

 

I believe that the consensus is: keyboards don't need an active DI, passive is sufficient.

 

Cheers, Mike.

[Mills Dude]

So, I should probably already know the answer to this question (since I own the keyboard) -- but--

 

For running the Roland RD2000 to a snake (and then front of house mixer), could I use XLR outs to directly go into the snake? I had thought the XLR outs could "replace" the need for a direct box. But since they're line level, does that mean I need to use a direct box?

 

No you don't need a DI box. Connect them like you mention â that will work fine. Tell the sound man to expect a line level signal.

 

Yes, technically, you don't a DI, but it may be beneficial to be prepared with one. I used to gig with an RD700SX with XLR outs. In some situations, FOH personnel were pros. Easy to just give them the heads up about the output being line level and they handled it just fine. In other situations with less skilled FOH personnel, those who don't really get the concept of gain structure, having an XLR at line level was very confusing. Sometimes, I could help them out and set the gain properly. Other times it wasn't possible. So swapping in a DI just made the problem go away. Having a Radial JDI Duplex in my bag saved me many times.

[stillearning]

If you do end up buying one or two DIs, and you plan to keep them, scratch your initials into them somewhere. Sound companies are usually in more of a hurry to tear down than the band, and will start wrapping cables and generally assume any DIs on stage are theirs. Your initials will come in handy when the time comes to look around for where yours ended up. Ask me how I know...

[Docbop]

It's a small transformer that converts a high impedance signal to a low impedance signal. Early days when I was in recording and sound it was just about certain transformers brands/model were better for audio than others and they just a TS type jack to transformer to a XLR jack that was the whole thing. Now some get really fancy like the Avalons with pre's built in.

 

Not much to them.

[U.Honey]

The purpose of DI box is to eliminate unwanted interference in transmission. It does that in two ways:

 

1. Convert unbalanced signal to balanced. The longer the unbalanced line, the more buzz and hum. A balanced line can run hundreds of feet without problems.

2. Isolate ground. This eliminates ground loop and the 60Hz hum that comes with it.

 

If you have an active DI you get the bonus option of amplifying the signal if needed.

Usuallly DI's come with the option to pad the signal (=attenuate) if needed.

[timwat]

I've mentioned this countless times on this forum over the years, but once more will increase my post count might help anyone new to this topic.

 

TL;DR: When buying a DI, I strongly suggest buying the most expensive unit you can afford. I strongly recommend Radial or Countryman (of the many I've personally used). There are surely other top-quality units out there, but I haven't used all of them.

 

Detail: I worked for several years as the worship director as a large church. I had the occasion to A/B several different brands / models of DI in one fixed, controlled situation using the same instruments, same PA, same installation. What I found was (for me at the time) revelatory. All DIs are not created equal. While most of them will get rid of your pesky 60 cycle as intended, many cheap ones degrade your tone and timbre in significant and alarming ways. This degradation is directly correlated to price. The sad part of all this is most users never have the time, availability or occasion to compare different DI boxes, right? At the venue, you either get hum-free signal or you don't. You never then say, "Hold on, let me try this OTHER brand of DI and see if there's a difference...". So rarely does anyone realize how lifeless, crappy, and weight-less your tone has become using that budget $30 DI. But like some other things in life, you generally get what you pay for. I wish I was endorsed by Radial, but I'm not - I just did the comparison.

 

I spent hours doing this, with all sorts of different instruments we had at the church. My conclusion? Many, many brands out there - sorry, I'll never use them again.

 

My choices? See above - Radial or the Countryman Type 85. I now have several different Radial boxes, and now use their Key Largo.

[Reezekeys]

OK I amend my advice - I still say you don't absolutely need a DI, but avoiding phantom power frying your output circuits is a definite plus, so use a DI! Of course fried outputs won't happen if the RD2000 has transformers before its XLR jacks, but I sure wouldn't bet on that. My original advice was also based on the fact the RD2000 has separate 1/4" outs, which makes it easier to deal with one's own monitoring situation.

 

Thinking about it, why even have XLRs on a keyboard? Any pro-type situation will probably be somewhere with DI boxes on hand. I guess it's the "semi" pro situations you might want to worry about - but those are the ones you'd really want that DI box for!

[EscapeRocks]

Thoughts on this scenario:

 

Mixer in keyboard gig rack uses Balanced XLR outputs: (no 1/4")

 

If I was using such a thing in my rig, I could just plug into the snake?

[ElmerJFudd]

Thoughts on this scenario:

 

Mixer in keyboard gig rack uses Balanced XLR outputs: (no 1/4")

 

If I was using such a thing in my rig, I could just plug into the snake?

 

Ya, I would. You set gain on the channel strip for your boards, the signal running to snake over balanced XLR outs is good to go! Does anyone disagree?

[Groove On]

Thoughts on this scenario:

 

Mixer in keyboard gig rack uses Balanced XLR outputs: (no 1/4")

 

If I was using such a thing in my rig, I could just plug into the snake?

1. If the snake goes to a mic-level input, you need to use a DI; it converts your mixer's line-level out to mic-level.

2. If the snake goes to a line-level input, connect your mixer directly to the snake. In this case, you don't need DI because it doesn't make any sense to convert your line-level to mic-level, and then plug it into a line-level input on the FOH mixer.

 

*** The main reason to use a DI is to convert line-level signals to mic-level *** why? - so you can plug line and instrument level equipment into a mixer's mic-inputs (like guitars, keyboards and mixers). If you're connecting to a mixer's line-level input, don't use a DI - it doesn't make any sense for the exact same reason you don't plug mics into a line-level input.

 

The only other bit of common sense I'd add - in any venue, make double-sure the tech actually knows which input they're using for your equipment. That's where the problems are, when people don't know the difference between line, instrument and mic-level. Don't depend on the connector (XLR, 1/4" etc.) to figure out if it's mic, line or instrument level, go to the mixer and make dang sure you know what that input is and what you need to plug into it.

[ElmerJFudd]

And the pad switch. Knocks it back down 26db if the mic input is too hot. Gain brings it up if too low.

[stoken6]

Mixer in keyboard gig rack uses Balanced XLR outputs: (no 1/4")If I was using such a thing in my rig, I could just plug into the snake?

Would accidental phantom power from the FoH desk fry your mixer? If so, a DI is good insurance.

 

Cheers, Mike.

[stillearning]

...2. If the snake goes to a line-level input, connect your mixer directly to the snake. In this case, you don't need DI because it doesn't make any sense to convert your line-level to mic-level, and then plug it into a line-level input on the FOH mixer.

 

*** The main reason to use a DI is to convert line-level signals to mic-level *** why? - so you can plug line and instrument level equipment into a mixer's mic-inputs (like guitars, keyboards and mixers). If you're connecting to a mixer's line-level input, don't use a DI - it doesn't make any sense for the exact same reason you don't plug mics into a line-level input...

Except that another purpose of a DI is to convert unbalanced to balanced, so you can run cables more than 20" to get to the FOH mixer.

 

Edit: I just re-read and saw that the specific poster you were responding to already has balanced outputs.

[EscapeRocks]

Thanks all......

 

 

So if I "needed" a DI...I'd have to get something like the Radial ISO, which is XLR in and XLR out

 

Again, this is hypothetical, as I don't have this setup. I use a Radial PRO D2 from the 1/4" outputs on my Focusrite18i20

 

Just thinking ahead if I were to change things up in the future.

[Reezekeys]

So if I "needed" a DI...I'd have to get something like the Radial ISO, which is XLR in and XLR out

 

Again, this is hypothetical, as I don't have this setup. I use a Radial PRO D2 from the 1/4" outputs on my Focusrite18i20

 

Just thinking ahead if I were to change things up in the future.

 

I'd probably get two of these - total $ for both is less than 1/2 the price of the ISO box you mentioned: https://www.radialeng.com/product/icecube

[EscapeRocks]

Thanks Reeze!

[Theo Verelst]

I suppose my built in electrical engineer feels about such a subject, of course electronics aren't easy for everyone.

 

I you have an un-grounded keyboard, mixer or other device (effects, lamp,..) on stage or in some room in the studio, and you're not certain you're on the same mains group, the name of the D.I. (Direct Input) unit becomes a description, especially in 230V situations, you want to make sure you don't get unpleasant voltages on your metal enclosures, guitar strings, output and input jacks when changing cables, etc. Many inputs of modern equipment will put capacitors between the two mains wires, to the ground. Now if the ground is not connected, that can give you a maximum of half the peak mains voltage voltage difference between for instance your output jack's metal housing and what should be considered "ground" where you are on stage. If another piece of equipment, like the mixer on a long multi cable, is connected to another group, and God forbid, would together with the power amps use no round, the voltage the metal multi cable enclosure could be considerable in such a way that the difference between your "floating" ground" and the mixers or amp's ground on another mains group could be considerably more. Just connecting your outputs/inputs may well blow up you equipment this way.

 

If someone where there's a current leak to ground makes your metal front panel electrified, and you touch it while touching a considerably different voltage (like another piece of equipment) , you could die. People have, it's no joke. Now to prevent most of that, and certainly the danger to humans, use always grounded equipment and extension cords for all musical equipment. That has the above mentioned disadvantage of at times creating considerable ground loops, which introduce hum into the signal, which to can be prevented by eliminating the ground connections in a loop by a transformer based D.I. box. The disadvantage is, unless you require a sound effect, a DI box's transformer will introduce some distortion to the audio signal, and it will cut low frequencies from some frequency downward, because transformers do so. A microphone level the magnetic distortions will be less than at line level, but it's probably still there.

 

Direct line inputs into a mixer are fine, but when the mixer is far away, the high frequency impedance of the cable might become an issue for a weak signal output of an instrument, which lessens high frequency content and introduces distortion in the output buffer. An instrument or mixer with high level and built in XLR balanced connectors probably do not have that problem. Ground loops are possible that way, though.

 

T

[CowboyNQ]

I"ve used a DI at every gig I"ve done since I was 18. At the first live gig I ever did the sound guy was MOST UNHAPPY I didn"t have one.

 

If the venue provides a sound guy I always require they provide a DI as part of the tech advance. If we are using our own PA I bring my own.

 

To answer OP"s question - way back in the day Mr Unhappy Soundy rather assertively explained to this unworldly teen that a DI:

 

1. Provides galvanic isolation (so you and your gear don"t get zapped)

2. Converts line level input to mic level input (makes his life easier)

3. Prevents the hum caused by ground loops.

[Mark Schmieder]

A lot of good and accurate feedback already, so I'll just focus on products now, and mostly for others here vs. the original poster.

 

I'm about to sell all of my DI's as I just upgraded to the new mk 5 version of Radial's large form factor JDV active DI.

 

Not for keyboards, mind you; I don't currently do large venue shows with keys (for some time now); I'll cross that bridge later if necessary.

 

No, this is more for home recording and also guitar and bass work as well as re-amping. Turns out the drag control makes this all-purpose.

 

For guitar/bass, I can match the impedance exactly, so the thru to the amp sounds the same as plugging in direct. Similarly with re-amping.

 

I used to have the passive stereo Jensen transformer Radial DI for live keyboard work. In the studio, I found the active DI's sounded better.

 

My active DI's for keyboard work are simply part of my mic pre-amps and audio interfaces. Audient ASP880 and True Precision 8 both rock!

 

I would have assumed passive was sufficient or best. Radial has corrected and updated their own explanations now, to explain the choice.

 

An active DI gives you more headroom, which usually translates to better sound and also usually means no colouration from transformers.

 

As Radial points out in the new JDV mk 5 lit, a standard power line gives way more headroom as well vs. using phantom power for the DI.

[Dr Mike Metlay]

I have a Radial JDI Duplex that comes to every gig with me. I don't use it often but it's a lifesaver when I need it. There are other companies than Radial that make DI boxes.... I think. I've never actually bothered looking around.

 

The newer JDI Stereo is a single-control-set DI for stereo devices rather than a pair of single-channel DIs in one box, so it's a lot cheaper, which doesn't make it cheap per se. My Duplex costs more than some of my iPads did, and I keep a close eye on it at every gig.

[Docbop]

Simple explanation and video if you like...

 

Link to: What is a DI box