Simple question?

[chriswanson]

Hi,

My fiddle has a sort of contact pickup. When I plug it straight into a little 30W amp it sounds great.

If i plug into a Behrenger mixer and then run out to the amp, it sounds a lot different -- weaker.

Do I need to do anything special to go into a mixer? Pre-amp like Fishman?

Thanks!

c.

[txstrat]

The way you describe it the mixer seems to pull down the strenght of the fiddles signal.
That would make it a problem of the mixer rather than the fiddle. The mixer might need a preamplified signal.

[Enzo]

The problem is one of equipment purpose. PA systems are meant to REproduce sound faithfully. They cover the full range of the audio spectrum. The frequency response is more or less flat so all frequencies are amplified evenly. Guitar amps are NOT designed to reproduce sound, they are primary producers of sound - they are part of the instrument. They are intended to add their own coloration to the sound. Otherwise they would all sound the same - like PA systems do. That is why guys will tell you "I play a MArshall" or "I play a Fender."

Plug an electric guitar into a PA channel - any PA - and it will sound thin and weak.

I think that would be the main reason for the difference in sound.

There are instrument preamps designed specifically for acoustic instruments, you might want to look into one of them. Or if you like the sound from the small amp, use it and mic it into the PA.

[chriswanson]

Hi,

thanks for responses.

just confirmed my situation here, and the signal from the mixer is definitely noisy and lacks bass compared to the straight-to-amp sound, which is not bad at all - quiet and sort of "full"..good enough to play live shows and sound fine.

Funny that it sounds so different when mixers are supposed to not alter the original signal. If I add a little pre-amp, do you think that Im going to just get a very loud, bad signal?

Do you think that a longish cable from the violin to mixer, maybe 10 feet, makes a difference? Does the Behringer company have a good reputation for quiet mixers?

I see what you are saying, Enzo...thanks for that point..

No hurry, but all comments appreciated. Thanks!

http://chriswanson.com/about.aspx

[Enzo]

Let's say you saw a beautiful actress on a movie screen. Then when you met her in person, her skin tone was not quite as glowing and her eyes looked a little puffy. You shouldn't think "I wonder why she is reacting to my presence that way." The movie MADE her look special.

The mixer WAS playing your signal without alteration, it is the guitar amp that is processing your sound to make it sound so nice.

Go to a music store wher you can try out products. Play your instrument straight into a mixer there for a baseline of performance, then add a preamp and try through the same mixer.

[chriswanson]

Enzo,

Well explained! Im catching on...

Only remaining question mark for me: I'm getting a fair amount of hiss when I use the mixer...do you think that my amp (30 watt crate acoustic instrument amp) has a noise-reduction feature? Cutting out common hiss frequencies?

its true that when i cut the treble down a ton and turn up the bass i get a lot closer to what i hear during direct connecting.

c.

[Enzo]

I don't know. Take the input out of the mixer channel and turn the mixer up with nothing plugged in. How much hiss is there now?

Guitar amps are not remotely flat and between the circuit and speaker tend to roll off pretty good by 5kHz. Of course turn up the gain on a guitar amp and you usually gert some hiss.

You didn;t mention it was an acoustic amp before. That alters the discussion somewhat.

Does your amp have a line out? Try feeding that to your mixer.

[Steve Conner]

My old band used to have a fiddle player with a similar pickup. As far as I know, they are passive piezos, and these need a high impedance load or they lose their bass response. Mixer line ins typically have 10k ohms, a guitar amp will have 1 Meg which is 100 times higher. So the mixer could be killing your bass by a factor of 100.

So yes, something like a Fishman preamp would help. Or maybe even an active DI box, which might be cheaper. Or maybe your little Crate acoustic amp already has a DI out, plug that into the mixing board.

[Enzo]

I stand corrected.

[chriswanson]

Hi,

OK, cool...I'll check that with a D.I. soon..I guess they might change the impedance that the mixer "sees"? Am I saying that right?

Enzo's point still much appreciated..im sure Crate has a nice formula for making my crappy pickup sound good during straight connections.

..ok, im reading about DIs at http://www.musiciansfriend.com/document?doc_id=102219 and wikipedia..possibly contradictory information about how they affect impedance. Anyway, ill give it a shot, and sounds like a good answer to my situation.

By the way, I'm using a clip-on Roland tuner pickup that cost about 15 dollars, and it works pretty well for rock and roll. Sounds like an electric guitar sometimes, but with nice vibrato I can sound like a violin again. And sometimes I actually want to sound like a guitar, you know.

[Le Basseur]

Hi,
I'm a violinist ( by trade) and I faced the same problems regarding the piezo PU/mixer/amp/DI thing.There are some thoughts:
1.The PU thing:
Try a Yamaha bridge with the incorporated piezo transducers.If the mechanical contact is weak (as is with most clip-on's...belive me,I tried enough of them),the output response is by definition weak and unequal.
2.The amp-vs.-mixer thing:
You said that the small amp you use is more "responsive" than the mixer.If it's dedicated "acoustic instrument" amp,then most probably it has a dedicated piezo input.This means that the input impedance as "seen" by the piezo transducer is very high (higher than 1 MOhm,tipically 4-5 MOhm) wich is "what doctor reccomended" for the piezo.AFAIK the input impedance is a critical issue and that's why I used a EF86 pentode in the first stage of my violin amp.On the other side,your tipical microphone input in a mixer has several times lower that value (OK for the mics/line in's but insufficient for a piezo).Aside of the impedance matching,the mixer input sensitivity and the better linearity are factors to be considered,as Enzo said.
3.The DI thing:
Frankly,I'm not sure if a piezo-DI-mixer signal route would solve your problem because the DI's main purpose(s) is (are) a little different than a source impedance matching,at least not of that magnitude(please correct me if I'm wrong).
On the other side,the noise issue you mentioned when plugged the piezo directly in the mixer's input might have something to do with the nature of signal itself.
As you know,the piezo signal is unbalanced (coax cable/jack).On the other side,the mixer input is balanced (XLR or TRS jack),meaning that when you plug an unbalanced source,one side of the mixer's differential input stage is shorted...I saw some mixers behaving very noisy in this situation but I wouldn't know if that's a general rule.This is where a DI should show all the benefits (a DI "converts" an unbalanced input signal to a balanced one) but,again,a DI doesn't have the needed input impedance for a piezo (again,my knowledge might be incomplete so please correct me).
My recomendations:
1.Use the best/stiffest piezo you can afford.
2.Plug the piezo in a dedicated piezo preamp (Fishman is a great thing but there might be others,cheaper,with similar results...or even a DIY box for a fraction of the price,why not?)
3.Use a DI between the preamp and the mixer and use the appropriate cable (balanced all the way between them).
4.Poor man's solution:if your Crate has a DI output,plug the piezo in the amp's input,keep the Crate running as a "stage monitor" and run a balanced XLR or TRS cable between the amp's DI output and the mixer's input...the results might be alot better.
Regards,