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Author Topic: Audio tools for testing to see if a speaker is bad  (Read 10767 times)

Greg Bartusch

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Re: Audio tools for testing to see if a speaker is bad
« Reply #10 on: April 01, 2014, 04:00:07 PM »

Is one side along a wall, and the other side open?

I run into this at a couple of our local clubs. The wall side will be louder due to coupling of the speaker & wall. I use the volume knobs on the back of the speakers (PRX) to balance things out.
Actually yes they are. The house right speaker runs alongside a wall while the house left speaker is in a open area.
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Ivan Beaver

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Re: Audio tools for testing to see if a speaker is bad
« Reply #11 on: April 01, 2014, 05:28:09 PM »

Pink noise will clearly demonstrate any differences and more obviously than a swept sine wave.
Agreed.

A sine wave tone will vary quite a bit if you move your head even a little.

Noise is MUCH better.
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Ivan Beaver
Danley Sound Labs

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Ivan Beaver

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Re: Audio tools for testing to see if a speaker is bad
« Reply #12 on: April 01, 2014, 05:30:04 PM »

Actually yes they are. The house right speaker runs alongside a wall while the house left speaker is in a open area.
That could be your problem.  The one on the wall could experience up to a 6dB increase in gain due to the boundary loading of the wall.

This will not be across the full freq band and the wall will actually introduce some cancellations at freq that are greater than 1/4 wavelength from the wall.

But the bass would be louder-making the overall level seem louder.
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A complex question is easily answered by a simple-easy to understand WRONG answer!

Ivan Beaver
Danley Sound Labs

PHYSICS- NOT FADS!

Greg Bartusch

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Re: Audio tools for testing to see if a speaker is bad
« Reply #13 on: April 01, 2014, 06:23:22 PM »

That could be your problem.  The one on the wall could experience up to a 6dB increase in gain due to the boundary loading of the wall.

This will not be across the full freq band and the wall will actually introduce some cancellations at freq that are greater than 1/4 wavelength from the wall.

But the bass would be louder-making the overall level seem louder.
Maybe I should swap speakers before I do a pink noise/sine wave sweep.
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Ivan Beaver

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Re: Audio tools for testing to see if a speaker is bad
« Reply #14 on: April 01, 2014, 06:46:35 PM »

Maybe I should swap speakers before I do a pink noise/sine wave sweep.
I would take both speakers-put them side by side-away from boundaries and run a single input into one cabinet and then unplug and run into the other and see if there is a difference.

A sweep is going to be really hard to hear differences.  I would not waste my time doing that.
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A complex question is easily answered by a simple-easy to understand WRONG answer!

Ivan Beaver
Danley Sound Labs

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Rich Grisier

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Re: Audio tools for testing to see if a speaker is bad
« Reply #15 on: April 03, 2014, 03:15:42 PM »

I work in a club and have a pair of JBL PRX525 and 518 subs. My question is.....When I play some music through the PA at unity, the house left speaker sounds lower than the house right. Before taking the speaker apart, is there a audio program I can run through the house system to determine exactly what speaker might be bad?

I use Room EQ Wizard to check speaker performance.

Here's what you'll need:
1. The software.
2. A computer.
3. An audio interface (I use a Presonus AudioBox USB)
4. A mic. (I use a dbx RTA mic)
5. The speakers in question (Having two or more is best so you can compare)
6. The cables to hook all this up.
7. Masking tape.
8. A mic stand.

Here's the goal: To see if there is a difference between speakers.
Chances are conditions won't be good to determine "THE" frequency response of the speaker. That's ok.  All we want to know is if one speaker is acting differently than the others in a given situation.

Here's what I do:
1. Set the speaker on the floor somewhere.
2. Put masking tape on the floor at the the four corners to make an "L" on the floor at each corner.
3. Set up the mic about 5' in front of the speaker pointed directly at the mid point.
4. Hook up all your cables.
5. Run Room EQ wizard to set levels.
6. Run the Sweep on Room EQ Wizard.
7. Swap out speakers placing the new speaker in the same exact position as the one you just measured.  Be careful not to bump the mic.
8. If this is an active speaker, make sure the volume level and switch selectors on the amp are set the same as the one you just measured.
9.  Run the REQW Sweep on the new speaker.
10. Look at both plots on one set of axes.  Look for differences in response.  One may have a dip/rise in frequency that the other does not have meaning a bad crossover... or maybe one has no high end at all meaning a blown driver.

In any case- this method takes all the subjective guesswork out of determining if there is a problem. 
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Greg_Cameron

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Re: Audio tools for testing to see if a speaker is bad
« Reply #16 on: April 03, 2014, 05:21:46 PM »

A sweep is going to be really hard to hear differences.  I would not waste my time doing that.

Agreed. Sweeps are, however, a great tool for finding blown drivers.
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Ivan Beaver

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Re: Audio tools for testing to see if a speaker is bad
« Reply #17 on: April 03, 2014, 05:44:26 PM »

Agreed. Sweeps are, however, a great tool for finding blown drivers.
Agreed-UNLESS you are running them at a high level-and then they will show the the HF driver you just blew up with the sweep------------------------

I don't think it is a driver in this case since the basic complaint was that one speaker sounds louder than the other-not that they sound different
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A complex question is easily answered by a simple-easy to understand WRONG answer!

Ivan Beaver
Danley Sound Labs

PHYSICS- NOT FADS!

ProSoundWeb Community

Re: Audio tools for testing to see if a speaker is bad
« Reply #17 on: April 03, 2014, 05:44:26 PM »


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