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DI BOX ISSUE

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DI BOX ISSUE

Postby azurmai » Fri Nov 04, 2011 12:41 am

Hi,
Do I really need to have a DI box in my home studio?
Can anyone tell me please what exactly the benefit would be, if i had one at home.
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Re: DI BOX ISSUE

Postby The Elf » Fri Nov 04, 2011 7:37 am

The most obvious use for a DI box would be to plug a bass guitar, or an electric guitar into an audio interface that lacks 'instrument' inputs.

But without knowing what other gear you have, or what problem you are trying to solve it's hard to know whether you need a DI box or not!
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Re: DI BOX ISSUE

Postby ef37a » Fri Nov 04, 2011 9:29 am

As Elf said "Waddyawantitfor?" (sort of!).

But then a DI* box is perhaps one of those things that are handy to have about the place because "you never know...". You can pick up a new, passive one for ~£20 but the active units are more versatile and should present the "proper" impedance to the guitar.

The top name is Radial but do checkout Orchid Electronics who make what looks to be an excellently specified active box, battery or phantom powered for about 1/3d the price of the Radials (any chance of "doing" their range SoS?).

*So we are all on the same hymm sheet. A DI box, unspecified means to me a device that converts a guitar signal to a balanced, lower source impedance signal suitable for feeding a microphone input. It will also have the capabilty to break the earth path between guitar (and possibly amp) and the mic feed. It is NOT a box for breaking earth feeds from soundcards to monitors or any similar duties.

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Re: DI BOX ISSUE

Postby JohnLardinois » Fri Nov 04, 2011 11:54 pm

The main purpose of a DI box, or at least it's intent, is to resolve impedance issues. They lower the impedance of an instrument plugged into it so that it doesn't lose signal when traveling to the input of the next device.

Impedance is electrical resistance in it's most basic sense. It's like friction for an audio signal, but not really...

The idea is that low impedance feeds high, which has the least resistance and allows the entire audio signal to make it to the input. With higher resistance, the signal loses vast amounts of information and can become unmixable. A DI box take a high imedance instrument like an electric guitar and converts it to a low one, so as it travels along the line to the input of the soundcard, the guitar signal is not lost.

Poorly managed impedance doesn't have much of an audible effect until you start mixing. You will notice the signal doesn't respond properly to EQ or even compression, and just refuses to fit into the mix, stand out of the mix, or be fixed at all. It's the most stubborn audio track you will ever encounter.

Here is the good news: If you're a guitar player, you probably don't need to spend money on a DI box. Most guitar pedals are designed in such a way that they act as DI boxes, although this is not their purpose. If you're a guitarist, just plug it into a pedal and run it clean!
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Re: DI BOX ISSUE

Postby ef37a » Sat Nov 05, 2011 6:58 am

Morning John.

I deliberately did not class a passive guitar as a "high" impedance device for it is not and herein lies the root of much of the myth and smoke about loading the instrument.

With all the controls at max, a Strat for example has a source Z of about 7-k Ohms but that is a weird and complex source and will change at different frequencies (which is why we refer to "impedance" after all!). Certainly as the volume pot is reduced the Z increases but it gets ever more resistive. I have just crudely checked my sons' Mex Strat and that is 6.9k at max and never goes above ~56k for any VC setting. I believe the "must be 1meg" myth started because all early guitar amps were of course valved, the guitar effectively fed in just post the detector stage of what was in principle the AF side of a radio and that was 1meg so as not to load the detector! Passive guitars will feed inputs down to 150-250k with little audible loss (indeed a very long lead could make more difference than going from 200k to 1meg)which is handy because that is about as high as a passive, transformer DI can manage!

The pedal suggestion is a very good one. Make sure it is not of the (daft IMHO!)"Tue Bypass" variety. An EQ pedal is a good choice as guitars can benefit from some middle suckout when not feeding a properly "voiced" amp and speaker.

Dave.
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Re: DI BOX ISSUE

Postby azurmai » Sun Nov 06, 2011 4:05 pm

Actually I am a classical guitar player. However I sometimes record electro guitar as well. And when I record it, its signal sounds too tiny. maybe it coz of the guitar amp I own or I really gotta buy a DI.
Thanx for the reply.
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Re: DI BOX ISSUE

Postby azurmai » Sun Nov 06, 2011 4:12 pm

Thanx for the inf.
So i just want to ask one more thing,
I was on google having a look at DI boxes you recommended but came across something like this; http://www.dv247.com/studio-equipment/m-audio-dmp3-dual-microphone-instrument-pre-amp--4808

is this a box that has both mic preamp circuit and di box circuit?
or does a preamp do what diboxes do?
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Re: DI BOX ISSUE

Postby azurmai » Sun Nov 06, 2011 4:21 pm

thanx JohnLardinois,
Yes im a guitar player but the classical one. So as a result of this i dont have pedals, when i have to grab my electro guitar, I just use NI Guitar Rig. But its signal is really low, thin as well as weak, it sounds as weak as a water dripping from the tap. So it doesnt satisfy me. thats why i am drugged into this dibox issue.
but what confuses me is whether or not i really need to buy a dibox to make it warm and stronger instead of a pre amp.
Or any suggestion apart from these?
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Re: DI BOX ISSUE

Postby James Perrett » Sun Nov 06, 2011 10:17 pm

I'm afraid that you are unlikely to get a good classical guitar sound without a nice room, nice mics and decent recording skills. Any attempt at DI'ing a classical guitar will probably result in a weird, lifeless tone. As a compromise, you might want to look at a soundhole mounted mic which would be a halfway house between a pickup and a properly mic'ed guitar.

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Re: DI BOX ISSUE

Postby azurmai » Sun Nov 06, 2011 11:18 pm

Sorry but you seem to misunderstand. It is the electro one not the classical one.
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Re: DI BOX ISSUE

Postby ef37a » Mon Nov 07, 2011 12:33 am

azurmai wrote:Sorry but you seem to misunderstand. It is the electro one not the classical one.
Join the club Az'!Recording a good electric guitar sound is tricky (find THE article on the subject SoS Aug 07). IF you have a nice little amp, AC15, a Dominator or any of a dozen good amps (check my user name out!) and you can have that cooking and mic it up maybe, just maybe you will, after quite some experience, get a good tone in the can. But even a 15watter working at its "sweet spot" is going to be way too loud most of the time.

Now a DI box will get a signal into the system but it won't, as a general, rule change the frequency response much, maybe just take off a bit of really top end "fizz" and that is what proper guitar amps do, they are "voiced". Every maker has their "curve" but they all comform to a bit of bass boost and some HF boost from about 3-4kHz then a pretty steep dive from 10kHz or so. Put another way, a broad midband suckout. Download Duncanamps tonestack calculator and you will see the basic voicing of the major brands.

So, your options are a decent amp, preferably one with an "emulated" output for quiet recording,or a pedal with comprehensive tone controls and an em'out if possible or an EQ (graphic) pedal.

Dave.
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Re: DI BOX ISSUE

Postby JohnLardinois » Mon Nov 07, 2011 1:10 am

James is right - recording classical guitar should be done with mics in a nice room, not with a pickup. If you're trying to record electric guitar with a mic, you have to run the guitar into an amp and record the amp. This is not recommended for classical guitar, as amplifier frequency responses generally don't go above 7-8kHz. You would loose a lot of sparkle, clarity, and air that makes classical guitar so attractive.

Here is a simple setup that doesn't require a DI box... usually. Get an acoustic guitar and two mics. One mic must be a cardiod pattern, and the other a figure eight. Place the cardiod facing the bridge side of the soundhole (brighter), and the figure eight placed perpendicular to the cardiod, so that the rejection is where the cardiod picks up. Next record your guitar.

In the mixer inside your DAW, duplicate the figure eight (bi-directional) track. Pan one left, the other right. Reverse the polarity (not flip the phase, these are two completely different things) of the right-panned track. Bring the cardiod back into the mix slowly in the center to create a mid-side stereo image.

This is a beautiful technique for classical acoustic, and captures a room well. Preamps are not necessary unless your soundcard doesn't have them. But keep in mind that if you buy a preamp, you now must buy an A/D Converter, power supplies, cables, summing mixer (possibly), and have a space to put them in. Mic Pres are not cheap.

The easiest, but most expensive way to improve your sound by purchasing new gear is to upgrade Preamps, Mics, and A/D Conversion.

The easiest, and cheapest, way to improve your sound is to closely study and practice gain staging, signal flow, impedance, distortion, noise, headroom, microphone placement, and acoustic treatment. Acoustic treatment can get expensive, but doesn't have to be. If you would like to know more about gain, signal flow, impedance, distortion, noise, and headroom, I will be glad to post the link to a lengthy article I am writing about these things. The article discusses the proper ways to improve the sound of your mixes and recordings without foolishly spending thousands on new equipment. The idea is that if you don't learn the cheap ways to improve your sound, you don't have the skill or musical responsibility to handle the expensive ways. It would be a waste to spend thousands on Pres, A/D, and Mics if you don't understand the basics.

If you want, I'll post a link. I'm not sure if I can, this is my first forum.

Happy Mixing

-John
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Re: DI BOX ISSUE

Postby JohnLardinois » Mon Nov 07, 2011 1:11 am

cardioid***
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Re: DI BOX ISSUE

Postby JohnLardinois » Mon Nov 07, 2011 2:33 am

A DI box is necessary if you're going Direct Injected into the soundcard (no amps or mics). Using a pickup would require this.

Here is a DI box from a trusted brand: http://www.sweetwater.com/store/detail/REDDI/

A Designs is wonderfully analog and transparent.
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Re: DI BOX ISSUE

Postby JohnLardinois » Mon Nov 07, 2011 3:41 am

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Re: DI BOX ISSUE

Postby ef37a » Mon Nov 07, 2011 8:01 am

Excellent tho' I am sure that Red unit is I bet it is going to be the thick end of £800 over here!

Then I am always wary of audio kit with valves* in it for the newb or inexperienced since replacement will be needed one day and that can be costly if you cannot DIY.

In any event the OP can get a bloody good amp for far less than 800quid with emulated output, FX send and return...Di-da.....Or...
Boss GE-7 EQ stomp box, job's a good'un.

*"Tubes" are what they wrap bog paper around.

Dave.
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Re: DI BOX ISSUE

Postby JohnLardinois » Mon Nov 07, 2011 7:05 pm

I agree, replacement would be costly, and can be difficult and dangerous to replace if you haven't done it before.
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