Would an audio test CD help trouble shoot a rattling noise in speaker?

Fairly common for the small cheap speakers used in most TV's to rattle when any significant bass levels are attempted.

Why not just use one of the DVD's you are already having trouble with? Turn up the volume, and bass controls if your TV has them. Plug the subwoofer output from the DVD player into the TV audio inputs if you can, then play almost any action movie with lots of low frequency rumble.

Can you plug your computer sound output into the TV audio input? Then you need a sinal generator/oscillator program that you can adjust the frequency to find the worst resonance frequencies for the TV speaker. But yes you could also make your own test CD's for nothing using a program like Audacity. A low frequency sweep signal is usually helpful.

Frankly I find simply tightening the speakers and packing any plastic surrounds with rubber to stop vibration helps, unless you want to really fix the problem by using much better external speakers. That always works for me.

MrT.

OK.

No point - wouldn't help. The usual way is to feed 3 VAC into the audio system and look for the rattle. Failing that, you need an audio generator to drive the system.

**No need to shell out big Bucks on a test CD. Just burn your own. Here is a freeware package which should allow you to do just that:

Just dial up a low frequency (say 50Hz) and test.

--
Trevor Wilson
www.rageaudio.com.au

Seg 8 - the slow sweep - is ideal for this purpose.

--
*Don't byte off more than you can view *

    Dave Plowman        dave@davenoise.co.uk           London SW
                  To e-mail, change noise into sound.

Its surprising how much distortion can be due to just a paper clip or bit of machining swarf touching the cone and attracted by the magnet. Try a different speaker on the same feed is my suggestion.

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

Don't remember what web site but I was able to download a couple drum samples which greatly aided my troubleshooting once. The piece I was working on didn't even act up using sine waves, only when lower frequency music was being played.

Maybe Google "download drum sample" and see what you find.

Mark Z.

The best check is a warbling sweep. Check out the one I suggested earlier. That's what speaker makers use.

--
*"I am " is reportedly the shortest sentence in the English language. * 

    Dave Plowman        dave@davenoise.co.uk           London SW
                  To e-mail, change noise into sound.

Sine waves can detect resonances. I have always used low bandwidth music,(AM radio) to shake up rattles in the higher registers. All you have to do is turn the switch and work the knobs, or buttons.

greg

Trouble is you can't *guarantee* random music will have the correct frequencies to show up a rattle etc. Hence the idea of using a repeatable test. The beauty of the 'warble' is going either side of the spot frequency tends to excite any resonance more readily.

--
*I believe five out of four people have trouble with fractions. *

    Dave Plowman        dave@davenoise.co.uk           London SW
                  To e-mail, change noise into sound.

How old is the TV?

I've seen really old ones where the cement used to adhere the speakers voice coil wire to the paper cylinder has deteriorated with age such that some of the windings come loose now float around, scraping against the other parts of the speaker. This is especially audible at lower freqs. I'd bet that's what it is.

Why not just try another speaker if it's old a lot of times the cone is torn or the speaker is just bad in some way.