looking to create the "music video speaker effect"

I

Ian Coughlin

Sophomore
Jan 11, 2011
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16
New York
www.dtgentertainment.com
I have a client that is promoting a weekly party called "stereo wednesdays" They have a bunch of 12" square coves in the wall and he wants to put subs in each one for aesthetics. I would like to create that over exaggerated/excursion look you see in music videos... and/or mount the subs on frosted plexi and put Color Kentics behind them and just have them flash to the music.

Thoughts/opinions/ideas?
 
Re: looking to create the "music video speaker effect"

Andrew Broughton said:
Use car audio woofers, they have very long excursions.
Click to expand...

And use a crossover that cuts off the high frequencies at a very low frequency, below 60Hz, to eliminate everything but the long excursion sounds. You don't want much music coming from speakers all over the room, just the super low frequencies.

Mac
 
Re: looking to create the "music video speaker effect"

Andrew Broughton said:
Use car audio woofers, they have very long excursions.
Click to expand...

Car woofers are nice, but cost massive amounts of money for a really crappy stamped-steel woofer.

Go to parts express and find some cheap home stereo woofer with a high-roll surround.

It will do the job quite fine, and cost almost nothing.

Something like this would do fine: http://www.parts-express.com/pe/showdetl.cfm?Partnumber=290-367 or even http://www.parts-express.com/pe/showdetl.cfm?Partnumber=292-412

You want something with a big Xlim. Xmax won't matter since they won't really be audible; you just want to keep them from clacking around.
 
Re: looking to create the "music video speaker effect"

wow, great find... the cheapest car audio woofers i found were at least $80 and had the brand name/logo on it. Makes the project much more affordable now and I can divert some money to other aspects of it... such as the amp or ipod with a 5hz loop lol.
 
Re: looking to create the "music video speaker effect"

does it have to go with the music, or just look cool?
for long term longevity you might be better off to mount some sort of servo or motor behind the magnet, with a rod through the vent hole attached to the cone.
in an unsealed box you should have no problem moving the cone at 1hz or less, and if you're good with electronics and want to link it to the music or do some fancier patterns than just sine waves it could be held in the full in/out positions a bit longer than natural, giving it more of an effect.

Jason
 
Re: looking to create the "music video speaker effect"

Jason Lavoie said:
does it have to go with the music, or just look cool?
for long term longevity you might be better off to mount some sort of servo or motor behind the magnet, with a rod through the vent hole attached to the cone.
in an unsealed box you should have no problem moving the cone at 1hz or less, and if you're good with electronics and want to link it to the music or do some fancier patterns than just sine waves it could be held in the full in/out positions a bit longer than natural, giving it more of an effect.

Jason
Click to expand...

I don't think a servo setup would offer any better reliability than the stock voice coil. It will take almost no power to get the cone moving below Fs, especially in an infinite baffle situation. Might I recommend a subharmonic synth processor with a very low low-pass filter, with a limiter carefully set up to not bottom out the woofer.
 
Re: looking to create the "music video speaker effect"

Since the "effect" was seen in a video, not live - There is a very strong possibility that it was not done literally, with real speakers, and helped with CGI.
On a small scale I have created foleys and helped set up effects for visuals so devices to create the "illusion" cannot be ruled.
I've yet to find out how it is done in the videos:
A wild idea: Using passive radiators in sealed cab with a pneumatic air pump modulated or pulsed. Air lines feeding cabs.
 
Re: looking to create the "music video speaker effect"

Silas Pradetto said:
I don't think a servo setup would offer any better reliability than the stock voice coil. It will take almost no power to get the cone moving below Fs, especially in an infinite baffle situation. Might I recommend a subharmonic synth processor with a very low low-pass filter, with a limiter carefully set up to not bottom out the woofer.
Click to expand...

my worry is that if you run the woofer at max extension, at lower frequencies than normal (to get the right effect) you'll probably overheat the coil.. a servo could do a 1Hz pattern to max extension with no burning smell :)

Jason
 
Re: looking to create the "music video speaker effect"

Jason Lavoie said:
my worry is that if you run the woofer at max extension, at lower frequencies than normal (to get the right effect) you'll probably overheat the coil.. a servo could do a 1Hz pattern to max extension with no burning smell :)

Jason
Click to expand...

How does excursion = heat? Just a few volts will bottom out a woofer below Fs in free air. Heat won't be an issue. I've "burned in" woofers for hours with 20Hz sine waves, set to just before Xlim, with no issues.
 
Re: looking to create the "music video speaker effect"

Silas Pradetto said:
How does excursion = heat? Just a few volts will bottom out a woofer below Fs in free air. Heat won't be an issue. I've "burned in" woofers for hours with 20Hz sine waves, set to just before Xlim, with no issues.
Click to expand...

I don't think you'll get the "music video speaker effect" without going well below 20hz, where the speaker gets inneficient, and may not move enough to cool itself properly. plus, I'm certain that to get the right look will take something other than a sine wave.

Jason
 
Re: looking to create the "music video speaker effect"

More wild ideas:
If the effect is to look pulsed ( imagine a DC battery on a momentary contact switch ):
Perhaps pulsed DC via a 555 timer: rate can be varied but not sure how to auto-follow beat.
A diode in AC line may do it. ( half wave rectifier )

Modify the Bass Beat Extractor?
http://sound.westhost.com/project62b.htm
 
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