Guitar to interface impedance matching

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icedsushi
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Guitar to interface impedance matching

Post by icedsushi » Mon Jan 17, 2011 9:29 pm

If I plug my guitar into the instrument input of my Audio Kontrol & press the instrument level button is it the ideal impedance?

I saw this gadget & they're explaining that there are many variations of "instrument level" which still aren't the right impedance for guitar:

http://www.motu.com/products/guitar/zbo ... vices.html

Is something like the Motu product necessary for the best tone or is that a somewhat gimmicky product? Makes me wonder also why they're selling such a product, does that mean their own interfaces aren't ideal for guitar either so use the Motu ZBox to plug your guitar into a Motu interface? :?

UKRuss
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Re: Guitar to interface impedance matching

Post by UKRuss » Mon Jan 17, 2011 9:32 pm

You'd notice if the input your are using is not hi-z. If the signal you are getting into your DAW is strong, I wouldn't worry to much about it. Your 'instrument level' switch is doing the job for you.

icedsushi
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Re: Guitar to interface impedance matching

Post by icedsushi » Mon Jan 17, 2011 10:14 pm

That's what I thought. I like the ambiguity they use to market the product & leave it up to your own doubts. They make it sound as if there are no interfaces that quite get it right for guitar without this thing.

hacktheplanet
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Re: Guitar to interface impedance matching

Post by hacktheplanet » Tue Jan 18, 2011 1:46 am

What's gimmicky or ambiguous about an impedance matching transformer? For $40, It looks like a pretty handy little device that could save you some headaches here and there.
Image

icedsushi
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Re: Guitar to interface impedance matching

Post by icedsushi » Tue Jan 18, 2011 2:41 am

Did you read the blurb or the manual online? They imply that most interfaces don't have the right impedance for guitar even though they might be made for guitar or have instrument level inputs. How you gonna know you have one of the interfaces that don't need it? So they kind of worry you into buying it. Kinda, you'll never know for sure with your interface unless you use this. :wink:

The other ambiguous thing is they don't tell you if you need it or not of you already use one of their interfaces. You would think if they were the experts on this kind of thing, the right impedance would be built right into their own product rather then having to buy an add-on to correct their own product.

I'm not complaining, just raising the question after reading this stuff, how do you know if what you already have doesn't need something like this?

LoopStationZebra
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Re: Guitar to interface impedance matching

Post by LoopStationZebra » Tue Jan 18, 2011 3:35 am

Russ is correct. If you are plugging your guitar (high impedance/hi-Z) into an XLR mic jack (low impedance/low-z), you could suffer from the sound getting thin due to the lower and mid frequences getting shaved, lol. The only time I've used one (DI) is when recording direct into a board. Ages ago, lol.

However, MOTU's XLR mic jacks on all their units have 1/4" high impedance jacks as part of the same input. So if you are plugging your guitar into one of those - or running from your guitar to a pedal board and then the MOTU, etc, you certainly don't need the ZBox.
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Tone Deft
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Re: Guitar to interface impedance matching

Post by Tone Deft » Tue Jan 18, 2011 4:18 am

icedsushi wrote:That's what I thought. I like the ambiguity they use to market the product & leave it up to your own doubts. They make it sound as if there are no interfaces that quite get it right for guitar without this thing.
read the wikipedia entry on 'bridging.'

you want matched impedances for things like driving speakers and amps so you get maximum power transfer. if you have an 8 ohm speaker you want to drive it with an amp whose outputs are 8 ohms.

with bridging you want maximum voltage transfer. the guitar puts out a pretty weak signal, it's just wires (guitar strings) moving in a magnet. bridging provides a very sensitive input to connect to.

saying you lose the mids or whatever is putting the blame on a side effect. what you lose depends on the impedance of the input, is it matched? is it lower than the source? those answers will give different frequency responses.
oddstep wrote:I agree with all of this. I'm just bored of writing "its music, just listen and trust your judgement"

icedsushi
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Re: Guitar to interface impedance matching

Post by icedsushi » Tue Jan 18, 2011 4:34 am

Great thanks! That clears it up for me.

Here's the part in the manual that was confusing for me. Assume anything with a "guitar input" is Hi-Z. Now look at the first sentence where they specifically say "guitar input". It's as if they're saying most stuff out there with a Hi-Z still doesn't work as well as it could with guitars. Then they go on to say "instrument" input:

http://s3.amazonaws.com/motu/manuals/gu ... ctions.pdf

"Guitar inputs on audio interfaces, mixers, PAs, wireless transmitters and other similar devices (often labeled “instrument”) usually have impedances that differ significantly from most guitar amps. This mismatch can make your guitar sound too bright, thin and brittle. ZBOX provides the proper input impedance levels to match your guitar’s output signal. The result? Your guitar sounds like it is connected to a real guitar amp and has a much warmer tone and authentic “response.” This is especially true when using digitally modeled guitar processing software (plug-ins) on your computer, audio interface, digital mixer, etc. ZBOX is the “missing link” for digital guitar processing, providing the hardware- driven input characteristics required to truly emulate a real guitar amp."

So according to Motu plugging your guitar into anything other than a mic input, you need this! :lol:

LoopStationZebra
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Re: Guitar to interface impedance matching

Post by LoopStationZebra » Tue Jan 18, 2011 4:52 am

Yeah, well. They can make all the claims they want (warmer tone :x ) but where's the actual testing/results? Have you found any reviews for this thing? None of the shops around me have any in stock, either. I was actual going to head out tomorrow and try one out, I'm that curious.

But again, the only reason you would need this with a guitar would be if you are plugging into any low-z input. Any interface or footpedal will pretty much have hi-z inputs for your guitar, lol. And who the fuck plugs directly into a mixer or soundboard these days? :lol:

*shrug*. I dunno. Maybe it will make my tone warmer as I plug into my PodX3 then into my Motu. Stranger things have happened.
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Tone Deft
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Re: Guitar to interface impedance matching

Post by Tone Deft » Tue Jan 18, 2011 4:57 am

more often than not the people that write that stuff don't understand what they're saying. they try but they can get it wrong.

check this sentence:
"ZBOX provides the proper input impedance levels to match your guitar’s output signal."

awful choice of words to use 'match' when what they're talking about is a matched input vs. a bridged input.

soldier on, always trust your ears and nobody else. :P
oddstep wrote:I agree with all of this. I'm just bored of writing "its music, just listen and trust your judgement"

Tone Deft
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Re: Guitar to interface impedance matching

Post by Tone Deft » Tue Jan 18, 2011 4:59 am

LoopStationZebra wrote:where's the actual testing/results?
it's just basic electronics.

guitars put out a very weak signal so you need a very sensitive input to connect them to.
oddstep wrote:I agree with all of this. I'm just bored of writing "its music, just listen and trust your judgement"

stefan-tiedje
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Re: Guitar to interface impedance matching

Post by stefan-tiedje » Tue Jan 18, 2011 8:35 am

icedsushi wrote:If I plug my guitar into the instrument input of my Audio Kontrol & press the instrument level button is it the ideal impedance?
I don't know your Audio Kontrol, but in most cases (all professional equipment I know of,) yes. An input labeled Hi-Z or instrument, especially if there is an extra switch, is made for electric guitars or basses (as if there are no other instruments...).
It doesnt match for piezo pickups, but the zbox does neither...

The zbox is useful if you have a Mixer or audio interface with only Mic/line inputs. Its a simple transformer, as it doesn't need power...
If you want to know if you need a gadget, never ask the manufacturer. They will tell you, you need it anyway.
If in doubt, trust your ears, they never fail, at least if you play an instrument...
(there are rumors that HiFi enthusiasts can hear a difference between gold-plated and other material in digital cables, but that is a case for psychology, not technology...)
If you can test the gadget in a shop and your ears tell, you need it, trust your ears, not me...

Some of the motu interfaces would need it, some not (as far as I know...)

Nothing more to tell about it...
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LoopStationZebra
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Re: Guitar to interface impedance matching

Post by LoopStationZebra » Tue Jan 18, 2011 2:53 pm

Tone Deft wrote:
LoopStationZebra wrote:where's the actual testing/results?
it's just basic electronics.

guitars put out a very weak signal so you need a very sensitive input to connect them to.


I know, but I'm asking with respect to Motu's device. Just did a search and I can find no meaningful reviews. Just some guys at Gearslutz saying it either adds nice warmth or it's shit and does nothing. :lol:
I came for the :lol:
But stayed for the :x

Khazul
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Re: Guitar to interface impedance matching

Post by Khazul » Tue Jan 18, 2011 3:20 pm

On the audio kontrol 1, line input 2 (with the line/inst switch) is a hi-z/normal line according to state of the switch. Should be fine for a guitar when on inst as then the input impedance is in order of 1M rather than the usual 40-50K or so for line inputs.

Dont use input 1 for a guitar however as this is switchable between line and mic - not the same thing.
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