Sensifivity of 2000-ohm Headphones
 

I am writing a program involving an antenna plus two coupled tuned circuits
plus a matched simple receiver.

I would like to know, crudely, the audio power input level to 2000-ohm, iron
diaphragm headphones for a nice, comfortable, not too difficult listening
level. Such as when the phones are used on a crystal and cat's whisker
radio receiver.

Such headphones are more sensitive than modern 8-ohm varieties. I have a
pair of 2000-ohm headphones but unfortunately no means of measuring power or
voltage input.

Just the number of micro-watts please. At what low power input level does
speech or music just BEGIN to fade out to a person of normal hearing? Any
ideas? I could take the average of a few replies.
----
Reg, G4FGQ

On Thu, 1 Jul 2004 19:43:02 +0000 (UTC), "Reg Edwards"
wrote:

I am writing a program involving an antenna plus two coupled tuned circuits
plus a matched simple receiver.

I would like to know, crudely, the audio power input level to 2000-ohm, iron
diaphragm headphones for a nice, comfortable, not too difficult listening
level. Such as when the phones are used on a crystal and cat's whisker
radio receiver.

Odd, I was just corresponding over this very matter recently.

Such headphones are more sensitive than modern 8-ohm varieties. I have a
pair of 2000-ohm headphones but unfortunately no means of measuring power or
voltage input.

Then we step into the area of conjecture.

Just the number of micro-watts please. At what low power input level does
speech or music just BEGIN to fade out to a person of normal hearing? Any
ideas? I could take the average of a few replies.

Hi Reg,

This will be have to be done through inference or Web research. As
far as inference goes, I will first state that magnetic speaker
efficiency is extremely poor, but I don't know if this extends to the
headphone implementation. Albeit, between 1 and 10% efficient.

The level of hearing for a child or teen fades out at 1db re
environmental impositions. Technically, in the absence of other
sounds:
1dB re 200µDynes per cM² at 1KHz

0dB = 200µDynes per cM² = 0.1 femtoWatt per cM²

a quiet whisper = 6 femtoWatts per cM²

conversation at 1M = 1 nanoWatt per cM²

Hearing at another frequency such as 400Hz (common sidetone for CW) is
10dB weaker (hearing peaks about 5dB in the 2-4KHz region) and worsens
as frequency lowers.

Hearing loss in the 50-59 Age group for men at 1KHz is about 10dB

Given "hearing" is subjective, a technical response is only as
accurate as the knowledge of these variables (age, sex, frequency,
efficiency).

73's
Richard Clark, KB7QHC

On Thu, 1 Jul 2004 19:43:02 +0000 (UTC), "Reg Edwards"
wrote:

I am writing a program involving an antenna plus two coupled tuned circuits
plus a matched simple receiver.

I would like to know, crudely, the audio power input level to 2000-ohm, iron
diaphragm headphones for a nice, comfortable, not too difficult listening
level. Such as when the phones are used on a crystal and cat's whisker
radio receiver.

Odd, I was just corresponding over this very matter recently.

Such headphones are more sensitive than modern 8-ohm varieties. I have a
pair of 2000-ohm headphones but unfortunately no means of measuring power or
voltage input.

Then we step into the area of conjecture.

Just the number of micro-watts please. At what low power input level does
speech or music just BEGIN to fade out to a person of normal hearing? Any
ideas? I could take the average of a few replies.

Hi Reg,

This will be have to be done through inference or Web research. As
far as inference goes, I will first state that magnetic speaker
efficiency is extremely poor, but I don't know if this extends to the
headphone implementation. Albeit, between 1 and 10% efficient.

The level of hearing for a child or teen fades out at 1db re
environmental impositions. Technically, in the absence of other
sounds:
1dB re 200µDynes per cM² at 1KHz

0dB = 200µDynes per cM² = 0.1 femtoWatt per cM²

a quiet whisper = 6 femtoWatts per cM²

conversation at 1M = 1 nanoWatt per cM²

Hearing at another frequency such as 400Hz (common sidetone for CW) is
10dB weaker (hearing peaks about 5dB in the 2-4KHz region) and worsens
as frequency lowers.

Hearing loss in the 50-59 Age group for men at 1KHz is about 10dB

Given "hearing" is subjective, a technical response is only as
accurate as the knowledge of these variables (age, sex, frequency,
efficiency).

73's
Richard Clark, KB7QHC

Rich, why don't you say you don't know. ;o)
---
Reg.

Rich, why don't you say you don't know. ;o)
---
Reg.

I would like to know, crudely, the audio power input level to 2000-ohm, iron
diaphragm headphones for a nice, comfortable, not too difficult listening
level. Such as when the phones are used on a crystal and cat's whisker

Hi Reg, Don't know either, but if you have access to a scope and a signal
generator, you could find out what you want. I have these, but not some 2000
ohm phones.
When I was a child playing around with crystal sets, I listened to a 1KW AM
station about 1 KM away with a 25' wire, a germanium diode, and a 1000 ohm
crystal earphone. The diode drop would be around 250 millivolts, and the
listening level would be fine. Thats 250 mv into 1000 ohms. Ther are several
crystal radio web sites that may provide more help.
73 Gary N4AST

I would like to know, crudely, the audio power input level to 2000-ohm, iron
diaphragm headphones for a nice, comfortable, not too difficult listening
level. Such as when the phones are used on a crystal and cat's whisker

Hi Reg, Don't know either, but if you have access to a scope and a signal
generator, you could find out what you want. I have these, but not some 2000
ohm phones.
When I was a child playing around with crystal sets, I listened to a 1KW AM
station about 1 KM away with a 25' wire, a germanium diode, and a 1000 ohm
crystal earphone. The diode drop would be around 250 millivolts, and the
listening level would be fine. Thats 250 mv into 1000 ohms. Ther are several
crystal radio web sites that may provide more help.
73 Gary N4AST

On Thu, 1 Jul 2004 22:18:27 +0000 (UTC), "Reg Edwards"
wrote:

Rich, why don't you say you don't know. ;o)
---
Reg.

On Thu, 01 Jul 2004 20:43:37 GMT, Richard Clark
wrote:

I don't know

Hi Reggie,

What if I said 43?

Do you actually read responses to your questions? Let's see, there's
enough numbers in it to satisfy lord kelvinator, and enough principle
in it to make sir plushbottom happy, and it even contains the
structure of another unzipped program.

Too demeaning to say thank you, hmmmm?

88's
Richard Clark, KB7QHC

On Thu, 1 Jul 2004 22:18:27 +0000 (UTC), "Reg Edwards"
wrote:

Rich, why don't you say you don't know. ;o)
---
Reg.

On Thu, 01 Jul 2004 20:43:37 GMT, Richard Clark
wrote:

I don't know

Hi Reggie,

What if I said 43?

Do you actually read responses to your questions? Let's see, there's
enough numbers in it to satisfy lord kelvinator, and enough principle
in it to make sir plushbottom happy, and it even contains the
structure of another unzipped program.

Too demeaning to say thank you, hmmmm?

88's
Richard Clark, KB7QHC

Reg Edwards wrote:

I am writing a program involving an antenna plus two coupled tuned circuits
plus a matched simple receiver.

I would like to know, crudely, the audio power input level to 2000-ohm, iron
diaphragm headphones for a nice, comfortable, not too difficult listening
level. Such as when the phones are used on a crystal and cat's whisker
radio receiver.

Such headphones are more sensitive than modern 8-ohm varieties. I have a
pair of 2000-ohm headphones but unfortunately no means of measuring power or
voltage input.

Just the number of micro-watts please. At what low power input level does
speech or music just BEGIN to fade out to a person of normal hearing? Any
ideas? I could take the average of a few replies.
----
Reg, G4FGQ

EH? WHAT DID HE SAY? :-)

--------------------
Irv Finkleman,
Grampa/Ex-Navy/Old Fart/Ham Radio VE6BP
Calgary, Alberta, Canada