Sound not really satisfying

Posted: 12/27/2011 11:15:07 AM

Joined: 12/26/2011

Hi everybody! I'm Matteo Silvestro, 18 years old, I'm Italian (so I apologize if I do any mistake) and I just got for Christmas a Burns B3 Theremin.

I fell in love with the theremin sound and with the way you play it, but as of now I can't get a sound that is satisfying.

By now I've solved some problems:

1. I've (well, my father did :D) replace the power supply with an Italian one (it says "OEM power adaptor Model:ADS18B-B 120100(L) Input:100-240V ~ 50-60Hz 0.5A Output:12V --- 1.0A")

2. I've understood that the pitch knob is needed to contract or expand the magnetic field, so I got to adjust it so that it doesn't make sound when my hands are far from the rod antenna - right?

But now I got a not-so-good sound - I connected it to my 2+1 audio system in my bedroom, and it's like (well, now it'll be difficult for me to describe it in English :P) it's hoarse, it's not clean, it's like drdrdrdr (onomatopoeia :D).

Now, what I want to ask you is:

1) Could it be that the power supply is wrong or something like that? (Check the specs up)

2) Do I have to get a better audio system or to get a guitar amp to get a better sound? (Is it necessary?)

3) Is it possible that it is due to computer, mobile phones and other eletronic things?

And as side questions:

4) Is it normal that in my bedroom (that is not very large) the pitch knob is almost at maximum level? (Very very contract field?)

5) The theremin is doing some "beep" sound today... is it normal?

I want to thank already who is going to help me... if you help me to solve my problems I'll be grateful forever and be a loyal theremin lover :D

Posted: 12/27/2011 12:29:28 PM

From: Colmar, France

Joined: 12/31/2007

Your drdrdrdrdr is an interference. It may come from the power supply, from a computer, a cell phone, a microwave oven, a nearby radio station etc. It can also be a grounding problem. It would be far better to connect your theremin to a keyboard or guitar amplifier which is correctly grounded through the mains cable.

The power supply for a B3 should be stabilized with a linear regulation. Switched mode power supplies are a "no-no" for theremins. It would be better to use a 15V version which gives a slight overhead, so that the internal voltage regulator of the B3 may operate within normal parameters.

The ADS18B-B 120100 is not good. I would use this one for the B3. La prossima volta mi chiedi prima!

The pitch knob is designed to adjust the size of the pitch field and to compensate environmental effects. The "normal" setup for a theremin is to put it onto a microphone stand and to adjust the height that your left hand is just above the volume loop when your upper arm is vertical and your forearm horizontal. 

You should then position yourself that while your left hand is in the position as indicated above, you are standing at about 60 cm from the pitch antenna. Now you should adjust the pitch knob so that the theremin makes no sound when you put your right hand near your right shoulder and creates an increasing pitch when approaching your right hand towards the antenna, always on an imaginary horizontal line between your shoulder and the pitch antenna.

Take care since the presence of metal or other electrical conductors (even an aquarium) near the theremin may strongly influence the pitch field.

The mic stand below the theremin and the power supply on the floor are not critical. Besides that, you should create a clear space with a radius of 2 meters around and above the theremin (lusters are the hell...).

Concerning the question if a good amplifier is necessary: The answer is "Yes"! The theremin is a precious music instrument and deserves suited accessories. You would not put rusty steel strings on a beautiful violin...

Posted: 12/27/2011 4:43:00 PM

From: Kansas City, Mo.

Joined: 8/23/2005

One way to locate the source of interference is to turn your theremin "on" and set the pitch control so that the theremin continues to make sound as you move away from it (that is, so that you can monitor the sound).  Then go through your room and, one by one, turn off equipment (i.e. computers, lights, etc).  If the interference stops when you turn something off, then you have located the source of the problem.

Posted: 12/28/2011 1:54:40 PM

Joined: 12/26/2011

Thanks a lot Thierry and kkssinger!

I already supposed that the problem was caused by the power supply, in fact now I got a ~13V one that does the work. The model is "MW AC-DC Adaptor PRI: 230V~50Hz 12.5W SEC: 1.2-3-4.5-6-7.5-9-12V --- 500mA 6VA(max)". (The volts are different because I can regulate them with a knob, now I selected 9V that effectively gives the Theremin 13V). Is there anything wrong or is it ok? And can the previous power supply have ruined my theremin? (As of now there's nothing that let me think of it)

Well, thanks to your advice, now with the Theremin and a Mic Amp or the Theremin and some headphones (even if it's very very low on volume), the sound is clear. I supposed I'll get a proper amp, but if I manage to I'll go to a music shop and try some of them (hoping I can do that).

Last 2 questions:

1) The theremin sometimes (but I supposed is caused by interferences) when I turn the knob suddenly goes to a super expanded magnetic field with a very acute sound: is that normal or is my theremin defective?

2) Do you think the B3 is a good theremin for starters? I've seen, for example, the Gakken Premium Theremin that is quite as cheap as  the B3 but has his own speaker and works also with battery, and there is also the audio output. Probabily a lot less problems.

Well, as of now the theremin got me mad. So so precious!

Posted: 12/29/2011 12:43:25 PM

From: Colmar, France

Joined: 12/31/2007

Connecting headphones directly to the audio output of the theremin may damage it. The audio output is ONLY for connection with an amplifier!

Your questions:

1) That is normal. Theremins are like ladies. They sometimes show unpredictable reactions.

2) Yes, the B3 is a good theremin for starters. But the Gakken Premium is a children's toy. You can imagine that if they include a small amplifier and a speaker, they must have taken very cheap components in order to maintain the low price...

Posted: 12/29/2011 2:13:39 PM

From: In between the Pitch and Volume hand ~ New England

Joined: 12/17/2010

Thierry said:

" 1) That is normal. Theremins are like ladies. They sometimes show unpredictable reactions."

And my Wavefront volume Response is like men. Too fast (ha!) and erratic ;)

Posted: 12/29/2011 2:29:03 PM

From: Colmar, France

Joined: 12/31/2007

@Amethyste: "Touché!" :-)

Posted: 12/29/2011 4:51:22 PM

Joined: 12/26/2011

Thanks a lot, I'm very glad of your advices! :D

Ok, I'll keep in mind that headphones can ruin the B3... well with all this things to know someone shuold make a guide to new thereminists, even for the ones like me that aren't very electronically skilled! :D

Are there other forbidden things I shuold know? My dad tried to put a isolated cable, is it dangerous? :D <-- little sarcasm here!

BTW, thanks for everything, I'll see if I can find a good amplifier (any advice? I hope to spend no more that €100) and a mic stand (here too, any advice? Is there some particular specs?)

Thanks again, hope you spend good holidays!

Posted: 12/29/2011 8:21:03 PM

From: Hillsborough, NC (USA)

Joined: 2/13/2005

I prefer the 3-legged mic stands over the ones with the heavy circular metal base.  I find they wobble less, and they're easier to transport because they fold up smaller and are not as heavy.

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