Explain the "push" test to check speakers

[Noose]

Type in "speaker repair" in your search engine and you will come across a million sites with guys advising others to gently push in on the speaker's cone with even pressure and lsiten fro scratchiness. Any scratchiness is supposedly a sure fire sign of a blown speaker.

I have done this to numerous speakers and I notice that if i am even slightly off when pushing in, I hear some scratchiness. I have to be vary careful to push in at just the right angle to not hear it. Every speaker Ive ever tried this with all produce that same scratchy sound unless I push in at just the right angle.

Could someone please explain this method of testing speakers in detail?

[BassmanPaul]

Essentially you are correct in what you are doing. The object of the excersise is to move the coil in its gap and listen for the coil rubbing. Even pressure at points around the dust cap all at the same time, hand held like a claw, should produce no noise if the driver is good. If you push unevenly then you can offset the coil and it will rub.

[mikeddd]

The "push test" is correct in methodology, but not in practice/practicality, as BassmanPaul pointed out. The "push test" is really just another tool for those that have somewhat of an idea of what they know they're doing. Sort of like "the battery test" for polarity. You're supposed to be able to use the push test with other tests and tools. Like using a DMM to check for a blown or shorted voicecoil. Even then, that doesn't cover everything. Sometimes a driver can measure out perfectly but when you play music through it, any abnormalities rise to the surface very quickly.

[Electricblue]

i imagine getting a round cup or glass and putting it over the dustcap and pushing it (rather than with fingers) is a more reliable and safe way to do things. IMO

[BassmanPaul]

Originally Posted by Electricblue

i imagine getting a round cup or glass and putting it over the dustcap and pushing it (rather than with fingers) is a more reliable and safe way to do things. IMO

Not really, in practice using one's hand can feel more than the ears hear.

[Electricblue]

Originally Posted by BassmanPaul

Not really, in practice using one's hand can feel more than the ears hear.

I mean in terms of newbies shoving their finger through the dustcap or un-even pressure deforming the coil, stuff like that.

Just my 2c, ive never tried it before

[Noose]

It is just so easy to push at a funky angle, thinking you are pushing in evenly and hear the voice coil rubbing in the gap. I see it on here all the time. A guy asks for help diagnosing a speaker problem. Invariably someone suggests the push test, giving very vague instructions, and suggests that if there is any scratchiness at all then the speaker is toast and cannot be fixed.

[billfitzmaurice]

Originally Posted by BassmanPaul

Not really, in practice using one's hand can feel more than the ears hear.

Just use the battery test. If you don't hear coil rub with the battery test then there is no coil rub. Pushing by hand one can tilt the coil in the gap, giving a false-positive for rub per the OPs experience.