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Post by honeyboy on Sept 21, 2009 8:54:21 GMT
Impedance (Z) is the resistance of a circuit to alternating current, such as an audio signal. Technically, impedance is the total opposition (including resistance and reactance) that a circuit has to passing alternating current.
A high impedance circuit tends to have high voltage and low current. A low impedance circuit tends to have relatively low voltage and high current.
When you plug a low-Z mic into a high-Z input you get a weak signal. That's because a high-Z mic input is designed to receive a relatively high voltage from a high-Z mic, and so the input is designed to have low gain. So you don't get much signal amplification.
Solution: Between the mic cable and the input jack, connect an impedance matching adapter. It effectively steps up the voltage of the mic, giving it a stronger signal.
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Post by Gerry C on Sept 21, 2009 9:14:02 GMT
Swot... Cheerily, Gerry C
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Post by percythewonderant on Sept 21, 2009 11:23:47 GMT
In the persuit of higher learning and as 'impedance matching adapter', is a phrase I havn't come across before, I just went to e bay and typed it in. Not a sausage. But google turned up refs. to the Shure A95UF Impedance Matching Transformer.
A completely reversible transformer which matches low-impedance microphones to high-impedance inputs or high-impedance microphones to low-impedance inputs.
Sounds as though this is the same thing?
I am really surprised that I have never been aware of seeing one before. I am the kind of person who says - "What's that?" and "What does it do?" and I am sure that I've never seen, (or noticed) one before.
What a useful little thing! Cheers Percy
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Post by Deleted on Sept 21, 2009 12:21:33 GMT
This is such an informative thread especially to those of us on the threshold of our first gig who haven't bought any amplification at all yet.
I wonder if I might ask for some advice.
We are a trio who play dobro (lap style), banjo/guitar and mandolin/guitar/harmonica. We have done some recordings using a mix of Behringer C-3 condenser mics and a Shure SM57 which sound pretty good and we are edging closer to doing a first live gig to around 80 people in a village hall.
We have a mixing desk with phantom power for 4 mics but no amps/PA as yet. We have no pickups - all mics and we share vocals.
Which way should we go in terms of miking and amplification? Money is limited to around £600.
Any advice gratefully received.
Alan
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Post by honeyboy on Sept 21, 2009 12:35:19 GMT
Percy,
The impedance adapter is usually a box with a jack on one end and a male XLR connector on the other. Inside the box is a simple transformer. Its primary winding is high Z, wired to the jack. The transformer's secondary winding is low Z, wired to the XLR.You plug (for example) a guitar lead into the jack, and plug the XLR into a mic input in a mixer. People used to use it with a bass guitar, electric guitar, or synth.
This impedance-matching adapter works, but is not ideal. The load it presents to the guitar might be 12 kilohms, which will slighly load down the high-Z guitar pickup, causing the dreaded 'thin bass' phenonenon.
An active direct box solves this problem. In place of a transformer, the active DI usually has an FET (Field Effect Transistor). The FET has a very high input impedance that does not load down the guitar pickup.
That is why the 'active direct box' has now largely supplanted the old (but fascinating) impedance matching transformer, when it comes to guitar pickup matching.
Now, if they only made such a device that dealt with 'talent', rather than impedance........
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Post by percythewonderant on Sept 21, 2009 12:42:40 GMT
Hi Honeyboy
If you come across a link for a low to high talent transformer please let me know. Its something I could do with!
alfagtvjan IMO If you are going for an entirely acoustic set It is worth looking around for a decent second hand PA. £600 will get you along way at the moment.
There are decisions that only you can make. Such as whether you are content to have a good all round sound or if you need true stereo separation. The if the former, entry level Yamaha systems are well worth looking at. Cheap and easy to use. But I am sure there will be many opinions.
Good luck Perce
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Post by percythewonderant on Oct 19, 2009 16:09:34 GMT
I found an E Bay listing for a clip on mic for reso’s
E Bay number 350235646461
Beautiful natural and transparent sound reproduction for any type of acoustic guitar or other instruments. The included preamp is powered by one AA Battery (not included) that will run for 1200 hours. Clips on to instrument and does not require drilling or marring of the instrument in any way. 16' cable plugs into any 1/4" input jack (amp, pa, other audio). Specifications: Electret Condenser Microphone; Frequency Response: 20Hz~16KHz; Pick-up Pattern: Omnidirectional; Sensitivity: -65dB; Impedance Type: Low impedance; Power Supply: DC 1.5V
This isn’t a new idea I have an old Shure SM17 which works pretty well when set up right. It works well on my tricone but IMO it operates best when combined/blended with a signal from a pick up.
Any comments?
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Post by Deleted on Oct 20, 2009 13:26:26 GMT
Clip mic...looks like exactly what Maplins sell for half the price....but a Shure SM 57 every time does the business...just learn how to stay on the mic.
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Post by Gerry C on Oct 20, 2009 14:02:51 GMT
alfagtvjan - Alan: here's a link toa site that may prove useful to you before that first village hall gig: www.bobmills.org/amu/ The 'amu' stands for 'all mixed up' and it's an invaluable guide to setting up a PA for acoustic instruments and mixing the sound. You can read it online and print off the 4-page summary for reference. I found it hugely useful a few years ago when I was suddenly called in to to sub for the soundman of a ceilidh band who was ill. Just be glad you don't have a fiddler who (a) won't use a pickup and (b) won't stand still at a mic!! Cheerily Gerry C
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Post by ianz on Oct 20, 2009 14:37:56 GMT
that is a cracking page Gerry - bookmarked!
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Post by Deleted on Oct 26, 2014 21:43:02 GMT
Hello folks. This is a great thread from some of the 'older guard'. I ended up here following honeyboy's MM blues & lace ultraslim magnetic humbucker review on youtube. In a nutshell, the MM sounded great mic'd, poor with the ultraslim, and kind of interesting with both. BUT I'm using an ultraslim through a zoom g2 pedal. There are so many things you can do with eq / volume / gain (including some classy amp reproduction sounds) that I'm doing the PA mans job - he just lugs the gear, moves a slider and takes care of the reverb. The main drawback with an ultraslim / mag is that it picks up no body sound. I whack and tap the body as part of the rhythm - and a piezo works really well for this. TT
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Post by obrienp on Nov 12, 2014 19:57:37 GMT
Interesting thread.
I had a Schatten NR-1 fitted in my MM Blues 28 by Robin when I bought it. I started gigging with a small acoustic band recently and the Schatten sounded OK with a boost (it's a passive pick-up) and tonal correction from my Zoom A3 pre-amp. It then goes into my Marshall AS100. However, it wasn't great. I have an AKG C1000, so I decided to improve the tone by using that as well and blending the two signals in the Zoom A3, which also provides phantom power for the mic. This gave a much better overall tonal balance but introduced the problem of feedback, so I have to be careful about signal levels and feedback filter settings (which has a trade off in tone). It's a lot of faff for the kind of pub/village hall gigs we do.
Last gig the Schatten started making horrible farting noises when I played the lower strings, so I had to unplug and just use the mic. Conclusion: it takes some getting used to doesn't it! A whole new technique to learn but a pretty good sound.
BTW: has anybody had the distortion (farting noises) problem with a Schatten? Is there a cure, or has the pick-up had it?
Slide on, Pat
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Post by obrienp on Nov 20, 2014 18:34:16 GMT
To add to my post above. Michael had a look at the guitar in question at Pocklington and recommended a Highlander replacement. The Schatten did sound pretty horrible direct into the PA at the Arts Centre; more shat-on than Schatten:-(.
Still wondering about whether it is worth spending over £200 (more fitted) on a pick up for a guitar that cost less than £500. It seems that loads of you manage fine with a mic. I may just have to learn to stay on mic. An SM57 as recommended by several people in this thread would be half the price of a Highlander and probably easier to gig with than my AKG C1000 condenser.
Any thoughts? Slide on, Pat
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Post by gordon on Nov 30, 2014 14:54:37 GMT
I don't have any technical knowledge to add to the discussion, but I had an really good experience sound-wise playing a concert last night and wanted to add to the wealth of testimonies here. I had a Highlander fitted to my MM Blues 28 because even though I prefer the sound with a mic, as I sing as well I tend to move maybe more than I should when I'm playing. With some eq'ing, the highlander sounds ok, not great but ok. Last night I had the luxury of time to set up and and a reasonable soundman, so we had a mix of the pick-up and a microphone placed in front and it sounded just great. Pretty sure I played better because I was happy with the sound.
Still, with a second-hand MM Lightning on its way - lucky find ! - I'm wondering about the Schatten NR-2 for it. Cheaper than the Highlander, easier installation .... I've read through the positive and not-so positive remarks here, and seen some good and not so good sounding videos of resonators with them fitted. Pat, I wonder if the fact of going through a pre-amp and working on the eq or through an acoustic amp rather than straight into the PA makes a big difference, it does for me with the Highlander. This one's not bad, sounds warmish and not too piezo brittle. I think I could live with that sound when mic-ing the guitar isn't possible :
Thanks !
Gordon
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Post by obrienp on Dec 2, 2014 18:26:02 GMT
Thanks Gordon. Enjoyed the video. It sounded pretty good to me.
I am holding fire for a little bit as no further gigs have come along recently but maybe an NR-2 should be an option. I have one of those attachments for my mic stand that allows me to fit a second mic (and boom if I want it) similar to Deuce's, which is what I am putting the guitar mic on. Now if I can just stop moving around so much.......
Slide on, Pat
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