Testing speaker connection with a battery.

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colliedogboy1
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Testing speaker connection with a battery.

Post by colliedogboy1 » Thu Aug 04, 2016 7:24 pm

For years I have occasionally tested soldered speaker connections by tapping the bare ends of the speaker cable to the terminals of a 9volt battery. When you hear a "pop" sound from the speaker, you know your solder joints are good and there are no shorts. Today, I did not have a 9volt battery, so I used the 18volt battery from my cordless drill. I got the usual "pop" sound from the speaker, but I saw sparks fly from one of the wires when it made contact with the battery terminals. Did I commit a major sin there, or is the speaker probably okay? It was a Peavey Impulse 1015 speaker, which I thought could accept upwards of 35 to 40 volts.(I think I thought). I guess I won't know for sure until I go back and connect the entire system and crank it up. What do y'all think? Be nice.

Dookie
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Re: Testing speaker connection with a battery.

Post by Dookie » Thu Aug 04, 2016 8:23 pm

If you gave it a very quick thump I think you'll be ok. There is both voltage and at what amps to consider here. Of course to find wattage its Voltage - Squared-Divided by speaker impedance. So 18 X 18 is 324. Divide that by 8 (ohms) and you get 40.5 watts. Don't know the amp rating potential of your battery so I wouldn't do that every day or very long. The horn or horn protection may not like it after awhile. I've used 9 volt battery myself for years with no problems. So long as I do it quick.
Let us know after testing if you had an issue.

Doug

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tele twister
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Re: Testing speaker connection with a battery.

Post by tele twister » Thu Aug 04, 2016 11:12 pm

You're braver than me. I've done this with worn out 9Vs, but when I see the cone jump like it just got defibrillated, I get a little freaked out.
Probably the better way to check connections, or for shorts, would be with a continuity checker or a multi meter.
I'm not sure if speakers can handle that much voltage, that quickly all at once. Hopefully it's fine.

Oh, and the ol' checking 9Vs with the tongue trick really, really freaks me out...I will never, ever do that again :shock:

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Wooferhound
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Re: Testing speaker connection with a battery.

Post by Wooferhound » Thu Aug 04, 2016 11:26 pm

I have an old transistor radio that I use to test speakers.
Just go out of the headphone jack straight to the speaker.
Portable battery power, and you can hear a lot more about it's operation by listening to it play music.

Never test a horn driver with a battery.
----- W o o f e r h o u n d -----

colliedogboy1
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Re: Testing speaker connection with a battery.

Post by colliedogboy1 » Fri Aug 05, 2016 10:16 am

Hey, I like the transistor radio idea! My sister has one that I think I can "borrow" for a while (infinity). Thanks, Woofer.

Gary Rabbitt
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Re: Testing speaker connection with a battery.

Post by Gary Rabbitt » Fri Aug 05, 2016 11:44 am

The 18v cordless battery is a little much for most any speaker. As someone said it's the Amperage that will cause harm. While a device may only draw the current it needs, the VC is pretty much a low Ohm coil and is going to draw quite a bit. Maybe to the point of the VC heating up pretty fast. I hope you didn't ruin anything on your speaker.
A very momentary tap might not hurt, but I would not take a chance.
The Ohmmeter is probably the best way to test for continuity. If you need to do a battery test, the quick 9v used battery will work, I use a couple of weak AA cells in series to click test. Many of the vintage radio speakers I test are best with the very small voltage.
Using a small sound source, boom box, transistor radio etc. to test is great too.
You do know the polarity will have a difference.? Positive on the + terminal will make the cone go outward, and reverse will make it go inward. Comes in handy if there are no markings on the speaker to determine polarity.

Lastly, I read recently where someone used a low voltage AC adapter that puts out AC to see if any part of the VC is rubbing the pole piece. The low voltage AC (3-5 VAC) will move the cone far enough to hear any rubbing for a couple of seconds.

BTW the 9V battery tongue test doesn't really bother me, dad showed us kids when we were young. But, when I found one of those 67 1/2v radio batteries I thought I'd test it too. I don't need to tell you what happened!

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Roger Crimm
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Re: Testing speaker connection with a battery.

Post by Roger Crimm » Fri Aug 05, 2016 1:07 pm

If you saw the way speakers are actually tested and burned in during manufacture, you wouldn't worry too much about the short bump from a battery test. They are tougher than you think.
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Gary Rabbitt
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Re: Testing speaker connection with a battery.

Post by Gary Rabbitt » Fri Aug 05, 2016 9:02 pm

I heard the factory tests might make one cringe, no doubt.:)
A short bump might be fine with the 18V battery, but any longer than the bump you're probably looking at some heating of the VC really fast.
Roger, at the factory do the use an AC current for testing? So the speaker pulses in and out? I would thnk that would be easier on the VC than a constant DC applied to the coil.

byacey
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Re: Testing speaker connection with a battery.

Post by byacey » Sat Aug 06, 2016 10:01 am

A 9v battery test Is really only useful for checking polarity. A much more Useful test is to use a sine wave generator at about 15hz. You will hear any rubbing and compliance tick easily, as well bad connections show up readily.

colliedogboy1
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Re: Testing speaker connection with a battery.

Post by colliedogboy1 » Sat Aug 06, 2016 3:18 pm

How much would a sine wave generator cost me?

byacey
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Re: Testing speaker connection with a battery.

Post by byacey » Sat Aug 06, 2016 5:49 pm

Here's a cheap one for $25. You need to drive a power amp with it, but anyone who is using speakers usually has a power amp at hand too.

grindboy5150
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Re: Testing speaker connection with a battery.

Post by grindboy5150 » Sun Aug 07, 2016 3:23 pm

Josjor had posted about a free app a while ago that has a sine wave generator in it, as well as a pink noise generator and a few others. (I'll see if I can dig up that link) On my Android smartphone, it is listed as SoundForm Signal Generator, deveolped by jjbunn. It seems to work well enough for a free app, they do have a version that you can buy and it adds more features. It is called Audiotool. It doesn't do every single frequency (exa. 70hz, 71hz, and 72hz all sound the same) but for free it definitely gets you in the ballpark. Also, I don't know for sure if the example I gave is true, just illustrating that 2-4 frequencies right next to each other don't get accurately reproduced. I just used 70-72hz as an example.

If you don't have access to Smaart or similar software, I think this is a good starting point.

grindboy5150
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Re: Testing speaker connection with a battery.

Post by grindboy5150 » Sun Aug 07, 2016 3:25 pm

Here's the topic link in this forum
https://peavey.com/forum/viewtopic.php?f=26&t=27840

colliedogboy1
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Re: Testing speaker connection with a battery.

Post by colliedogboy1 » Tue Aug 09, 2016 3:56 pm

Well, I couldn't get my sister's transistor radio-she says it's "collectible" from the 1960s- but I did hook my Walkman-type CD player to a speaker, using a 1/8" stereo to 1/4" mono adapter cable, and it does work! I did not know that a headphone output had enough voltage to get a sound from a speaker, but it does. It isn't loud, but it is loud enough to let you know you have a good solder joint plugged into your speaker which, in my case, was 20 feet high in the air. They were going to remove their scaffolds the next day, so this was my last good chance to make changes to the speaker and/or to the connector which we had just plugged into it. No amps were in place yet. I will remember this tip and will keep my little CD player in my toolbox for the next such event.
Thanks, everyone.

noelmem1
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Re: Testing speaker connection with a battery.

Post by noelmem1 » Wed Aug 17, 2016 9:30 am

i dont have a sine generator so i used a stepdown transformer 12v2A plugged to the outlet (60Hz)to test for rubbing while tightening the 3 bolts on the BW, it can take it all day long no problem . A monentary 18v battery into the impulse to check for polarity will be no problem too. The crossover blocks DC to the horn.

noelmem1

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