Topics

Speaker query #ubitx

tommason56@...
 

Gents. Many thanks for your responses, very much appreciated. 
73.
Tom
M3TEG.

Steve
 

While Tom's got your attention on speakers, I've got a interesting problem:  I have a 1.5", 8 Ohm speaker I liberated from an old FRS radio.  As you can imagine, the sound quality from this speaker on the BTX40 is not very good.  However, when I encircle the speaker with my thumb and forefinger, the volume and clarity improve dramatically.  I've tried putting it in a piece of PVC, or surrounding it with a metallic "ring", and no change.  What gives?  Do I have magic fingers?  BTW the MFJ 281 accessory speaker is working pretty good for my '40.  My first (of many, I suppose....) post to the group.  Hope I did this right....Aloha, Steve WH6ST

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Tim Gorman
 

Some speakers require a specific damping factor to sound the best. A
small speaker in a small case, e.g. a microphone, has a high damping
factor, it keeps the speaker cone travel from moving too far. Your
fingers may be doing the same thing. Volume depends on the amount of
air the speaker moves. With no damping it may be moving out to the
maximum point of travel and just vibrating at that point instead of
using the full travel possible from the speaker.

tim ab0wr

On Sun, 21 Jan 2018 07:58:06 -1000
"Steve Thatcher" <stevep2p@...> wrote:

While Tom's got your attention on speakers, I've got a interesting
problem: I have a 1.5", 8 Ohm speaker I liberated from an old FRS
radio. As you can imagine, the sound quality from this speaker on the
BTX40 is not very good. However, when I encircle the speaker with my
thumb and forefinger, the volume and clarity improve dramatically.
I've tried putting it in a piece of PVC, or surrounding it with a
metallic "ring", and no change. What gives? Do I have magic
fingers? BTW the MFJ 281 accessory speaker is working pretty good
for my '40. My first (of many, I suppose....) post to the group.
Hope I did this right....Aloha, Steve WH6ST

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www.avg.com
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ohwenzelph
 

On Sun, Jan 21, 2018 at 09:25 am, <tommason56@...> wrote:
Gents. Many thanks for your responses, very much appreciated. 
73.
Tom
M3TEG.
Best speaker:
Impression/suspicion from following this thread for a while is that with the Bitx40v3, which uses a LM386, that people have been happiest when the speaker is not tiny, so maybe 4 to 8 inches would be good, and it seems like 16 ohms might be better than 8.


Nobody mentions how many watts the speaker is rated for so maybe that’s not an issue.


If you do some comparisons and think you have found a definitive solution to the question then please post it. I have tried a bunch of smaller 8 ohm speakers and some are a bit nicer than others but so far have no conclusion as to which direction is best. There is a lot of high pitched sound that I do not need, above 3 kilo hertz, that comes out of my bitx40v3, I have attenuated it some but don’t know where it’s coming from, and I would like to get rid of it at the source.

Good luck!
 
jerry aa1of/6

philip yates
 

Mine is a 2watt rated ex-Yaesu VR5000 speaker.
8Ω 2w 3inch.

Think you have to take into the baffle effect of the panel that its mounted behind, mine sounds
good, saying that I did plug it into my Yaesu SP-8, decided that the 3inch speaker was far better.

Phil - G7BZD

On Sun, Jan 21, 2018 at 6:47 PM, ohwenzelph via Groups.Io <Ohwenzelph@...> wrote:
On Sun, Jan 21, 2018 at 09:25 am, <tommason56@...> wrote:
Gents. Many thanks for your responses, very much appreciated. 
73.
Tom
M3TEG.
Best speaker:
Impression/suspicion from following this thread for a while is that with the Bitx40v3, which uses a LM386, that people have been happiest when the speaker is not tiny, so maybe 4 to 8 inches would be good, and it seems like 16 ohms might be better than 8.


Nobody mentions how many watts the speaker is rated for so maybe that’s not an issue.


If you do some comparisons and think you have found a definitive solution to the question then please post it. I have tried a bunch of smaller 8 ohm speakers and some are a bit nicer than others but so far have no conclusion as to which direction is best. There is a lot of high pitched sound that I do not need, above 3 kilo hertz, that comes out of my bitx40v3, I have attenuated it some but don’t know where it’s coming from, and I would like to get rid of it at the source.

Good luck!
 
jerry aa1of/6


Dave Bottom <ars.kd6az@...>
 

The issue with small speakers for communications use is that you want something quite different from HiFi speakers in several aspects.

While I use headphones exclusively for operating, I do like to “read the mail” (listen) while working in the shop. 

The key is proper frequency response, good absorption of sound off the back of the diaphragm to limit distortion caused be the reflections hitting the diaphragm, and proper strength magnet to control the voice coil movement.

For our communications headphones we build a metal frame, Mylar cone driver with Neodymium magnet that provides high sensitivity but huge dynamic range, 200-6000Hz response to cut off noise that is of no value and quite fatiguing to listen to and the Mylar cone (diaphragm) is not disturbed by moisture and temperature changes to give excellent control over the voice coil positioning.

I could make available to the community a kit with a 50mm, 32 Ohm driver, foam dampening and mounting hardware (3mm standoff’s, Screws, lock washers and nuts) 2 mounting points, if enough people are interested. I can make one and show how it could be installed.

 Output can be attenuated even as these are easy to drive and the uBITX has tons of output.

Dave WI6R
Google “radiosport headsets” 


Sent from my iPhone

On Jan 21, 2018, at 10:51 AM, philip yates <phil@...> wrote:

Mine is a 2watt rated ex-Yaesu VR5000 speaker.
8Ω 2w 3inch.

Think you have to take into the baffle effect of the panel that its mounted behind, mine sounds
good, saying that I did plug it into my Yaesu SP-8, decided that the 3inch speaker was far better.

Phil - G7BZD

On Sun, Jan 21, 2018 at 6:47 PM, ohwenzelph via Groups.Io <Ohwenzelph@...> wrote:
On Sun, Jan 21, 2018 at 09:25 am, <tommason56@...> wrote:
Gents. Many thanks for your responses, very much appreciated. 
73.
Tom
M3TEG.
Best speaker:
Impression/suspicion from following this thread for a while is that with the Bitx40v3, which uses a LM386, that people have been happiest when the speaker is not tiny, so maybe 4 to 8 inches would be good, and it seems like 16 ohms might be better than 8.


Nobody mentions how many watts the speaker is rated for so maybe that’s not an issue.


If you do some comparisons and think you have found a definitive solution to the question then please post it. I have tried a bunch of smaller 8 ohm speakers and some are a bit nicer than others but so far have no conclusion as to which direction is best. There is a lot of high pitched sound that I do not need, above 3 kilo hertz, that comes out of my bitx40v3, I have attenuated it some but don’t know where it’s coming from, and I would like to get rid of it at the source.

Good luck!
 
jerry aa1of/6


Doug W
 

Dave
That does sound interesting.

Tom VE3THR
 

Beware of your speaker! Twice I've been fooled by what I thought was a def rx'er. Turned out to be a bad internal speaker both times. The frame of the speaker can be easily bent by certain mounting methods - resulting in distortion.
My BITX40 case has a 2"  8 ohm 0.25 W front facing speaker. Fantastic audio. Trade out front panel space for better sound if you can. Test your speaker before you mount it in a case. It's always been a pet peeve of mine that most commercial rigs put speakers on the top or bottom of their enclosures. Put an external speaker jack on the rear panel. Remember that sound is in the "ear" of the beholder.