OT? testing computer speakers with cell phone?

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i have two pairs of advents, one has everything on the right and the other has everything on the left.
fortunately, they're labeled, so it doesn't actually matter.
the only thing that happens if they're reversed is it sounds wrong. no harm is done.
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nospam wrote: "the only thing that happens if they're reversed is it sounds wrong."
How does it sound wrong? It's not a matter of polarity, it's just a matter of left switched with right.
I guess left-switched-right could sound wrong if you are intimately familiar with the stereo positioning of elements on specific songs or albums. Something I'm actually amazed that so many fm stereo radio stations can't seem to get right!
I recall back in '87, when "Sgt. Pepper" debuted on CD over several NY City metro rock stations, two stations were playing "When I'm Sixty-Four" at about the same time. On one station, Paul's vocal was on the right, on the other, it was on the left! Did not all components in a station's studio or tower chain have the same convention for ID'ing Left & Right(white left and red = right) - to ensure proper hooking up?
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wrote:

All of this is because of my friend. He wants a speaker to run the wire through the wall between his kitchen and his office, to stream a local radio station on his laptop that his radios won't receive.
I suggested wireless. He wasn't interested.
I pointed out speakers come in pairs but he wasn't interested.
So earlier, on one of these 3 groups I asked about software to convert stereo sound to monaural, and I've been trying out various software, just in case he shows signs of discontent. But it's been hard to test the stereo/monaural of the software when one of my speakers didn't work!!
As it happens, with my own speakers, the non-powered one is broken and I've been trying to fix it. I've known about using a battery -- I figured it out myself 40 years ago -- but I forgot. Since the light was on on the non--powered one, I opened it up and besides a couple wires all it had was a speaker and a 1000uF cap. The speaker measured 4 ohms, so I replaced the cap. Didn't help!! But finally I used a battery, and it makes a distinct noise when even a mostly dead 9v battery is connected the first time. After that, it doesn't make any noise until I remove the battery and short the plug. Then it makes the same noise, well, probably the opposite noise. So it's probably good.
In a storage box buried somewhere in my house I have an RCA jack to 3.5mm plug adapter, and when I find that, I'll try the speaker off the cell phone.
But I guess it's the powered speaker that has a problem with the second channel. It's not the sound card because I replaced both speakers and then both worked.
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Micky wrote:

Electrolytic capacitors can be NP (Non-polarized) or they can be the polarized type. If working your magic with the battery, you want to charge the capacitor according to the polarity symbols. Plus on the battery goes to plus on the capacitor. If you reverse the power to a polarized capacitor, it can blow up on you. It will fill the room with black sooty deposits floating in the air, if that happens. (Someone in electronics lab did the usual trick, reversed insertion, as a joke. So we got a demo of what a mess it makes.)
https://cdn.sparkfun.com/assets/a/5/6/1/6/525458c8757b7f28258b456a.jpg
There is a little info here on NP capacitors. And how to make one. It isn't mandatory to use an NP capacitor in this application. You might use an NP cap in an amplifier with symmetric powering (+/-15V rails maybe). Whereas a cheap computer speaker probably runs off one rail, and so a polarized cap would always be charged correctly to some sane voltage.
http://electronics.stackexchange.com/questions/21928/can-you-make-a-non-polar-electrolytic-capacitor-out-of-two-regular-electrolytic
The home made amplified speakers on my new computer, are DC coupled. It's a bridged amp, using two amp chips, and that allows removing the cap entirely. As the circuit is so well balanced, less than 10mV DC appears across the speaker when idle. (I was really impressed it came that close to zero!)
This schematic shows a polarized capacitor in series with the speaker. Schematic is on page 3. This is a single rail amplifier (+13.2V nominal). The purpose of the capacitor, is to prevent DC from appearing across the speaker terminals. (So the cone doesn't have a decided mechanical bias while running, preventing full travel.)
https://www.quasarelectronics.co.uk/kit-files/electronic-kit/3047.pdf
On page 6 here, you can see the "bridged" configuration. One amp goes up in voltage, while the other one goes down. Giving more power. And, as a bonus, the DC output of the two amps is matched closely enough, when the amplifiers are idle, there is no net DC across the speaker terminals. The large electrolytic in series with the speaker can then be removed. So if the amp on page 6 was driving your speaker, the big capacitor would not be inside the cabinet.
http://datasheet.digchip.com/670/670-00274-0-UTC_TDA2003.pdf
My amp is actually a stereo kit, so there are a total of four amp chips to produce stereo. Yes, the circuit still has electrolytic caps, just not 2200uF ones. The volume controls, while pretty to look at, I set them once and never dialed them again. I use the volume control on the computer for that.
http://www.canakit.com/Media/400/1051.jpg
Paul
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writes: []

And to prevent coil heating.
--
J. P. Gilliver. UMRA: 1960/<1985 MB++G()AL-IS-Ch++(p)Ar@T+H+Sh0!:`)DNAf

Advertising is legalized lying. - H.G. Wells
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J. P. Gilliver (John) wrote:

I suppose. There would be nothing to cool the coil at all.
Someone here lists some possible causes of the speaker coil burning out.
http://www.focal.com/en/content/420-why-do-voice-coils-burn-out
Paul
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writes:

True, but especially in the case of a DC bias.

Oh dear, I'm not too impressed with that article: between stating the obvious, and various woolinesses and untruths, I have the feeling the author only has a tenuous grasp on the subject - or, being at my most generous, has something in mind but very poor ability to communicate it, possibly through trying to simplify.
--
J. P. Gilliver. UMRA: 1960/<1985 MB++G()AL-IS-Ch++(p)Ar@T+H+Sh0!:`)DNAf

All's well that ends.
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Paul in Houston TX wrote:

You can swap left and right channel with cabling. The following two, plug red cable into white hole, white cable into red hole, oughta do it. You would think someone could make a compact solution to do this, but I never seem to be able to locate such an animal.
2 x RCA Male, 1 x 3.5mm Stereo Female, Y-Cable 6-Inch
https://www.amazon.com/3-5mm-Stereo-Female-Y-Cable-6-Inch/dp/B000I23TTE
3.5mm Stereo Male to 2 x RCA Female
https://www.amazon.com/Plated-Stereo-Female-Adapter-Splitter/dp/B0146L3VDQ
While sound cards typically have a special option for swapping Center/Sub, the practice does not extend to all output ports. When it really should, as the OS should be able to "patch panel" anything, given a chance.
They could also have put a DPDT switch on the speaker housing, to implement "reverse" channel assignment on the master speaker, but of course that's never going to happen. Too "inelegant".
Paul
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Me neither.

Yeah, these ought to do it. (Good idea. I may want to do this myself some day. )
My friend hasn't complained yet. He doesn't even have the speaker yet, and he probably won't complain.

I have seen wireless speakers that give a choice of L, Mono, and R. This is good for me, because I buy a pair of speakers and put one in one room and one in another. I listen to a lot of talk radio where stereio doesn't matter, and a lot of http://www.181.fm/ , which I get with RadioMaximus, free software that doesn't rely on the webbrowser to play any of 100 stations (plus you can put in your own, if you know a good link. Though not every link I think should work works.).
181FM is oldies radio, and much of that stuff was recorded in mono also, though some was sort of converted to stereo.
Anyhow, in the last 180 hours, I've noticed 1 or maybe 2 songs where I couldn't hear the singer, and I assume that's because he was on the other channel.
Otherwise having only one channel has been fine.
My friend listens mostly to classical and of course the violins should be on the left, etc. So maybe if he only has the right channel, he won't hear the violins much. So that's why I wanted to know which channel he was likely to have. I'll feel him out to see if he's satisfied and if he's not I'll tell him about the software, once I've evaluated all of them.
I'm playing the speaker I'm going to give him right now, but I don't know how to tell if it's left or right.
....Am I stupid? It occurred to me I have dl'd the manual for the next size bigger from the same company, and I looked at it, and it had a photograph of the back of the powered speaker with a wire marked "To the left speaker". So I looked on the back of the speaker I'm using and it said the same thing! I still learned something from your answers. ;-)

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Micky wrote:

On amplified devices, I use the "hum" test.
Take the 1/8" plug, and don't connect it to the computer. Touch your finger to the end contact (Tip). The left speaker should have a slight bit of hum in it, from your finger.
Now, touch your finger to the middle contact (called Ring). The right speaker should hum.
You can use that to test amplified computer speakers at a flea market, as long as there is AC power to run the amp.
No need for a Walkman or other signal source to run a signal into the amp.
The hum test does not give any indication of balance across the audio spectrum, so the test is not conclusive in terms of "whether the thing is crap or not". The hum test is basically just a continuity test, proving the item is "an amp". Not a "good" amp.
A computer amplified speaker should have enough gain, and a high enough input impedance, that you should hear some hum, when you turn up the volume and start touching the 1/8" plug contacts.
Paul
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Micky wrote: "OT? I think a craigslist guy I bought computer speakers from told me that one could test speakers without a computer by plugging them into a cell phone. So you can test them before you buy them, even if you don't have a computer with you and don't have the nerve to ask the seller to connect them to his computer.
Did I get that right?
Has anyone done it?
Does the plug fit the jack? (I don't think so. Some headphones came with an adapter but I'll have to look for it, so I'm asking first, and also to tell you about this.) "
Powered(or unpowered) computer speakers should be able to fit into anything with a 'Mini' - 1/8"/3.5mm female jack.
I have a reason for asking this Micky, but what was a top hit on the radio in the year you graduated high school?
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On Sat, 11 Jun 2016 16:36:15 -0700 (PDT), snipped-for-privacy@gmail.com wrote:

I'm sure there was a Beatles song or two. I wasn't crazy about the Beatles but I spent years trying to learn to like them like everyone else did.
Eventually I noticed violins in Eleanor Rigby and other non-4-piece band instruments and I said to myself, Well they get a lot of credit for that. And I went with that theory for 10 or 20 years until I paid more attention to Paul Anka and lots of other songs from the 50's and 60's and many of them have violins etc.
And the lesson was that if people want to believe in something, because everyone they know does, he can convince himself. I've seen it, wrt not just music tastes but more important things too.
But I can't really distinguish one year from another 42 and more years ago, especailly after years (3 hours tonight) of listening to a mixture of years on oldies radio. I like the Crystals, the Temptations, Paul Anka, Neil Sedaka, Martha Reeves and the Vandellas, the Four Tops, and loads of others (including some single female singers I can't think of now) and all of those who are from the period of the 50's and early 60's and not too dissimilar. I like 20's, 30's, and 40's music too, and classical symphonic and opera** and was just learning to like Country, which would have made it everything, when they came out with acid rock, which I never learned to like, and rap is even worse. So I'm just like a lot of old fogies, and I like what was popular when I was a teenager (except the Beatles and the Rolling Stones) and nothing after that.
(Well there are a few songs every year, ballads and whatever, like "I will always love you", that would fit with any decade, including the 50's. And the lyrics were almost always clean until about 1963 or 4, but I rarely listened to the lyrics so that's not why I didn't like the later songs.)
**I get more done when I listen to popular music.
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On Sat, 11 Jun 2016 21:24:26 -0400, Micky

John Lennon was asked......'Is Ringo the best drummer in the world.' John said......‘He's not even the best drummer in the Beatles.’
(Not true, but still pretty funny)
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Micky wrote: "I'm sure there was a Beatles song or two. I wasn't crazy about the Beatles but I spent years trying to learn to like them like everyone else did.
Eventually I noticed violins in Eleanor Rigby and other non-4-piece "
Alright, so you're probably a bit older than the average poster on this Usenet group, judging from your response you probably attended high school around 50 years ago,
Guys, have some respect for Micky, seriously! He's trying to learn this stuff, so just explain it, and leave the sarcasm and drama out of your replies. Might come a time when you all need to ask HIM a question about "way back when", so, what goes around comes back around.
Just sayin'
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On Sat, 11 Jun 2016 21:24:26 -0400, Micky

And that I liked, if it wasn't clear. And there were as song or two I suppose in the 50's every year that I didn't like.

Here's an example:
1960 by The Shirelles, another girl group that I liked.
"Will You Love Me Tomorrow"
Tonight you're mine completely You give your love so sweetly Tonight the light of love is in your eyes But will you love me tomorrow
Is this a lasting treasure Or just a moment's pleasure Can I believe the magic of your sighs Will you still love me tomorrow
Tonight with words unspoken You say that I'm the only one But will my heart be broken When the night meets the morning sun
I'd like to know that your love Is love I can be sure of So tell me now and I won't ask again Will you still love me tomorrow
Wikip says "However, [the lead singer] Owens recalled on Jim Parsons' syndicated oldies radio program, Shake Rattle Showtime, that some radio stations had banned the record because they had felt the lyrics were too sexually charged." So as vague and ambiguous as the song is, at least for people not already thinking in sexual terms, it was marginally acceptable. And the others were just about love and not about sex.
And another factoid, Because I didn't collect records (with pictures on the covers), go to concerts (where were few if any in Indianapolis, and expensive when my mother was a widow). and didn't watch American Bandstand, I had no idea which singers were white and which were black. I still often don't know.
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On Saturday, June 11, 2016 at 3:38:33 PM UTC-4, Micky wrote:

Test? I have computer speakers in my basement with sub that I plug my phone into all the time. This is common. The input to the speakers is probably a basic 1/8" stereo connection. Works for phones, tablets, and I'm sure some refrigerators. Very common. The seller is correct. This is the way to test them.
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