Sound problem, converting +4 DB to -10 DB ?

[bart bervoets]

I need to make a cable to convert an audio signal of +4DB to -10DB
(broadcast audio to consumer level)
How can i do this best, can i just solder in a resistor, if so, what value?

Bart Bervoets

 

[Bob Horvath]

On Thu, 25 Sep 2003 14:23:22 +0200, "bart bervoets" <nekobe@online.be>
wrote:

Maybe this will help.
http://www.hut.fi/Misc/Electronics/circuits/speaker_to_line.html

I need to make a cable to convert an audio signal of +4DB to -10DB
(broadcast audio to consumer level)
How can i do this best, can i just solder in a resistor, if so, what value?

Bart Bervoets

 

[Kyle Miller]

"bart bervoets" <nekobe@online.be> wrote in message news:<3f736c65$0$31719$ba620e4c@reader1.news.skynet.be>...

I need to make a cable to convert an audio signal of +4DB to -10DB
(broadcast audio to consumer level)
How can i do this best, can i just solder in a resistor, if so, what value?

Bart Bervoets

A resistor would introduce an impedance mismatch in your cable line,
which could distort the audio signal. If you know the impedance levels
of each audio device, you may be able to build a resistive divider
circuit that would retain the correct impedance levels of each device.
The signals of +4db to -10db would I believe be approximately 30 times
as much signal voltage in the broadcast audio device. Perhaps a 30:1
metal oxide resistor network would work.

 

[Jerry G.]

What you want is a 14 db pad. If your broadcast unit is using balanced
audio, and your device is using unbalanced audio, this will be a bit
complicated to easily do, if you want the quality maintained.

If you refer to any of the audio reference books, or even do a search on the
net, there are sites that will show graphs, and give the formulas for the
signal reduction, and maintain proper impedance. The conversion from
balanced to unbalanced, or the other way, is what can get complex to do
properly.

If you go to the page below it is all very well explained
http://www.tape.com/Bartlett_Articles/db_or_not_db.html

Near the bottom, they give an example for what you want. But it is done in
a shortcut way. The proper way is to use some active circuitry, and it would
be a bit complex to design yourself.

--

Greetings,

Jerry Greenberg GLG Technologies GLG
=========================================
WebPage http://www.zoom-one.com
Electronics http://www.zoom-one.com/electron.htm
Instruments http://www.zoom-one.com/glgtech.htm
=========================================


"bart bervoets" <nekobe@online.be> wrote in message
news:3f736c65$0$31719$ba620e4c@reader1.news.skynet.be...
I need to make a cable to convert an audio signal of +4DB to -10DB
(broadcast audio to consumer level)
How can i do this best, can i just solder in a resistor, if so, what value?

Bart Bervoets