impedance question

Hello guys, I started reading a lot lately about impedance matching and all the stuff around it anyway and I was just wondering if any of you know what impedance would come out of an acoustic guitar (morris tornado deluxe ZIII) with a 9 volt battery powering the mic inside.

I'm not sure thought whether its piezo pick ups, I dont know much about this subject yet. but I really believe there is a mic inside it (if I try and speak above the hole of the guitar it catpures my voice)

Thanks a lot

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Demetri, don't worry too much about impedance matching, as it doesn't really apply too much to your situation.

The critical thing about impedance is that the output from an amplifier should be reasonably matched to the load from the speaker or speaker cabinet. If this is got badly wrong, some major damage can happen to the amp.

In your case, you're talking about the impedance of the guitar output into the amp. Normal guitar or bass pickups send a pretty high impedance (several thousand ohms) signal to an amplifier. Piezo (acoustic) pups, "active" circuits and outboard preamps tend to send a low (tens of ohms) impedance signal. Neither will hurt the amp, but the amp's circuit may not be best designed to cope with this for the best tone.

If your amp has a "Hi Z" and "Lo Z" choice of inputs, then plug the acoustic into the "Lo Z" input for best results. If you don't have such an input, then tweak the eq, but you won't, definitely won't, burn the amp.

Hello there! thanks a lot for your reply! I basically want to connect my guitar on my computer's soundcard (M-audio 1814) I have line inputs (which are the has the less inpedance for the cable I have to connect my guitar TS-TS) the impedance is 10Kohms. and I also have the mic imputs which are low impedance but they are XLR. do you reckon it will be better if I buy a cable TS to XLR to connect my guitar on that ouput or should I just connect it on the line input?

P.s I also have an instrument input HI-Z but I didnt really like the sound from that input or maybe it just me?

and as well if I buy a di box, they are hi-z usually and trasnfor to low-z would that work for my guitar as its low-z?

Thanks a lot for the help

I would try the line input first. The impedance is about right for your acoustic's piezo output. If it's a little too flat, you may find the jack-xlr cable worthwhile getting to plug into the mic input. I'm not surprised the instrument Hi-Z sounds a bit poor. It would work fine with a normal electric guitar but it will remove a lot of the treble on a low-impedance instrument like yours. As I said, you will not do any harm to guitar, soundcard or computer so try things out and see what you like.

Keep us posted on how you're getting on :)

hello there, I tried to record both line in and instrument input, the recording sounded pritty much the same to me but when I monitored both files equalization with voxengo gliss EQ I noticed that the one I recorded from the line in roll off all the frequencies above 16 Khz (there werent any frequencies after 16Khz) is it a good or a bad thing?
The instrument input one on the other hand had complete frequency spectrum.
I thought my own that the complete one should be better so I just recorded a tiny guitar part and I would really like to here your opinions about it. how good or how bad sounding is. This completly unprocecced


I also proccesed it as well and this is the procecced one


can you pls tell me what you think about this one as well? how good or bad the proccecing is?

P.S: I'm only trying to improve my skills on guitar sounds

Thanks a lot


I haven't yet had a listen because I need to download a ".rar" decompressor. I'm sorry, I'm in the middle of something at the moment and I've been tied up. Have you had a look at Bob Houlston's "Computer recording" thread here? It's

and may be a useful read, perhaps to contribute a post to. If the line in rolls off at 16kHz, does this really have an effect? Even for acoustic piezo, I would've thought that there's not much contribution above this frequency. I promise to check your files and have a listen, but if the line-in sounds better to you, go with the ears rather than the oscilloscope.

I'd really like to say thanks a lot for helping me out with this stuff firsly! when you get time and listen to parts I recorded I'd be really glad to hear whats your opinion about them.
As for the best sounding one (instrument In VS line in) I really cant tell much difference in the sound. the only thing is that the line in I think because it didnt have any frequencies after 16 khz it sounded kinda "fake" in a way. but maybe it still just me. I will record both line in and intrument in the same pattern and post it in here so you'll have a listen and tell me what you think. you seemed to know miles better than I do!
I'm a student btw and I'm still learning this stuff now, I really like them and I just want to be able to do something good!

Thanks a lot!

I know what you mean. The removal of a tiny bit of nth order harmonics can have that effect of making a recording 'fake'.

BTW, we're all students here; still learning. I'm definitely closer to kindergarten than expert :) . Look forward to hearing more.

demetrisag wrote:
I basically want to connect my guitar on my computer's soundcard...

At risk of seeming to be a dreadful bore I have used the Behringer PB100 for computer recording and found it to be most useful and versatile. It will match many microphone and musical instrument low level signals, including piezo guitar pick up, to the line input on a personal computer system unit. You can read my review at URL:
Best wishes,
Bob #==(o )
p.s. My previous post may be useful:
Computer Recording
This is a basic method and explanation. Ensure all audio settings are set low to avoid overload of delicate equipment and speakers. Using a Windows 98 enabled Personal Computer or PC I recorded my guitar as a WAV file and then converted it into a MP3 file for upload to the internet using free software. Most guitars whether electric or electro-acoustic use a standard ? inch or 6?8 mm jack plug which requires connection to shielded audio cable. At the other end you will probably require a 3?5 mm stereo plug wired for a mono connection which will be inserted into the line or microphone socket on the rear panel of the PC unit. With the speakers on you should be able to hear your guitar amplified through the PC. If not, ensure that relevant audio pathways are not muted by clicking once on the speaker symbol on the task bar to reveal volume setting and click twice to reveal line in channel settings. Go: START > ALL PROGRAMS > ACCESSORIES > ENTERTAINMENT > SOUND RECORDER to record the WAV file and then use the free MusicMatch download to convert to MP3 and reduce file size as required. I use the 16 kbps setting when converting to minimise file size and ensure a fast loading for the listener although this does reduce sound quality. It may be possible to buy the lead ready made or use an adaptor with a regular guitar lead. A Cathode Ray Tube or CRT monitor may cause audio interference via the pickup of an electric guitar. Experiment with playing position to reduce hum. You may hear my work via

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