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Author Topic: Best way to test speakers that return from a rental?  (Read 9436 times)

Brad Gibson

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Re: Best way to test speakers that return from a rental?
« Reply #10 on: March 20, 2017, 09:46:17 PM »

What is your process when a speaker comes back from a rental to make sure it is still in good condition?

Now lets throw a powered speaker at this situation.  How are we getting an impedance curve if the speaker has an amp built in?
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Tim McCulloch

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Re: Best way to test speakers that return from a rental?
« Reply #11 on: March 20, 2017, 11:44:51 PM »

Now lets throw a powered speaker at this situation.  How are we getting an impedance curve if the speaker has an amp built in?

You can't without opening up the cabinet or modifying it.

You're back to acoustic testing.

Are you having specific issues now or it this meant to be preemptive?
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Matthew Knischewsky

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Re: Best way to test speakers that return from a rental?
« Reply #12 on: March 21, 2017, 01:10:46 AM »

We currently use this method and it seems to work about 90% of the time.  Do you know of a full proof tester that will take the guess work out of the equations?  Im looking to take the human error factor away.

While not impossible to "remove" the human factor it may become cost and time prohibitive to do so.

As others mentioned, tone sweep will tell you most of what you need to know. Combine with a FFT measurement will tell you if it's in the ballpark.

Establish a test procedure- This area of the warehouse, this location, this mic, etc then document it. Make initial captures of your inventory, using serial or inventory numbers to keep track. You're not going to get laboratory results but that's not what you're looking for- you're looking for the trends in magnitude response, not necessarily absolute measurements. If the speaker passes the tone test, the FFT compared to a previous trace will show any other problems fairly clearly, such as a polarity reverse, drivers lower in level or non functional, passive components damaged etc.

For lack of a better and easier test I've made this work for as long as I've been using Smaart, It's very eye opening when problems do pop up, and it's a great way to learn how to make a good measurement and use discretion when in the field.

Matt
« Last Edit: July 02, 2020, 11:08:58 AM by Matthew Knischewsky »
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Chris Grimshaw

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Re: Best way to test speakers that return from a rental?
« Reply #13 on: March 21, 2017, 04:36:42 AM »

I'd go for an acoustical measurement, but ignore the frequency response almost entirely. Look at distortion.

If one mid driver out of four is toast, chances are it's gonna make some nasty raspy noise at some frequency, or the other three drivers will be working harder. That'll show up quite obviously in a distortion measurement. Same for a bass driver that's had beer poured over it - the cone will end up a lot softer, and that's gonna show problems too.

Inventory moving around isn't a problem, so long as nothing rattles during the sweep.

Chris
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eytan gidron

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Re: Best way to test speakers that return from a rental?
« Reply #14 on: March 21, 2017, 05:34:23 AM »

What is your process when a speaker comes back from a rental to make sure it is still in good condition?

Outline makes a nice and useful unit for testing multiway loudspeakers -

http://outline.it/outline-products/loudspeakers/browse-by-series/grand-touring-outline/fastqc-ls/

It's designed for Outline speakers bat can be used with any type of speaker as long as it is not powered and as long as it doesn't have capacitors in series. Very useful for testing line arrays.
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Brad Gibson

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Re: Best way to test speakers that return from a rental?
« Reply #15 on: March 21, 2017, 05:45:13 PM »

You can't without opening up the cabinet or modifying it.

You're back to acoustic testing.

Are you having specific issues now or it this meant to be preemptive?

Not any real problems at this point.  We are all about making processes and continually improving them.  I have learned everything I know by reading and asking questions.  Everyone has something to offer if you just shut up and listen. 

Thanks Tim, I have learned tons from you and will continue to listen. 
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Adam Daube

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Re: Best way to test speakers that return from a rental?
« Reply #16 on: March 21, 2017, 06:20:57 PM »

What is your process when a speaker comes back from a rental to make sure it is still in good condition?

I tone sweep my rig as others have stated. but at the same time I check the impedance of every driver, first with a whirlwind cabdriver (for fast checks, it only gives me an led for 4,8 or 16 ohms) and then I have a test cable jig made up to test each component with my meter with out having to open up the cabinet.

My tone sweeps are normally just ear tests. testing with Smaart in the shop has too many other interferences. 
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Kevin Maxwell

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Re: Best way to test speakers that return from a rental?
« Reply #17 on: May 03, 2020, 10:18:22 AM »

I recorded a repeating sweep tone and play it back into the speaker under test. I need to edit it and make it repeat for a longer time. It starts low enough and goes high enough without going past the necessary frequencies. With this method you are doing a repeatable sweep. And if something sounds funny I use the sweep app to pinpoint the distorting frequency.

I swept a system setup for a musical because something sounded funny and discovered it was something it the room that was rattling. I also discovered in another room that an installed sub mounted on a wall had the mounting hardware rattling at one tone. 
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John Roberts {JR}

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Re: Best way to test speakers that return from a rental?
« Reply #18 on: May 03, 2020, 10:30:25 AM »

If you have a lot of speakers it may be worth setting up a permanent test fixture... You can curve speakers with wideband or shaped noise, and save the results for each speaker. Then after rental returns sweep them again and confirm response. this should be pretty time efficient.

JR
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Tim McCulloch

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Re: Best way to test speakers that return from a rental?
« Reply #19 on: May 03, 2020, 11:50:11 AM »

If you have a lot of speakers it may be worth setting up a permanent test fixture... You can curve speakers with wideband or shaped noise, and save the results for each speaker. Then after rental returns sweep them again and confirm response. this should be pretty time efficient.

JR

This is what the big rental shops do... a dedicated testing area and a database entry for each DUT.  Barcode scanning can make it faster...

For mass screening I use impedance with pink noise.  JBL has specs for each pass band and if off by more than 1 Ohm, it needs further inspections... Then we do a sine wave sweep to listen for loose hardware (we have to remove the hinge bar rigging hardware on the VerTec, you can't stop it from rattling), torn cones, torn or loose suspension parts.
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"If you're passing on your way, from Palm Springs to L.A., Give a wave to good ol' Dave, Say hello to progress and goodbye to the Moonlight Motor Inn." - Steve Spurgin, Moonlight Motor Inn

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Re: Best way to test speakers that return from a rental?
« Reply #19 on: May 03, 2020, 11:50:11 AM »


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