giant "back to the future" subwoofer for real - Page 1
Forum section: electronics / general

author: Noise Floor
author_rank: Regular Contributor
timestamp: June 14, 2014, 04:46:14 pm
content: I'm glad they summarized it fairly.

author: FrankBuss
author_rank: Unknown
timestamp: June 14, 2014, 05:38:14 pm
content: Quote from: Noise Floor on June 14, 2014, 04:46:14 pmRight, I wonder why it doesn't appear louder in the video with that much power. Must have a terrible efficiency factor. Or they need to connect an additional guitar amplifier and use it with a guitar

author: SeanB
author_rank: Super Contributor
timestamp: June 14, 2014, 05:46:29 pm
content: Probably the AGC of the camera used, along with the built in microphone having almost zero response at the 34Hz used. Most camcorder microphones have a very steep filtering below 150Hz to reduce both mains hum, handling noise and wind noise. They are in no way going to be good at recording bass notes. Most of the recording seems to be the regular speakers used as mid range ( if you can call using a 10 inch woofer as midrange, but with that big sub it is so) and tweeters.

author: BennyBoy
author_rank: Contributor
timestamp: June 14, 2014, 11:33:50 pm
content: Doc's was full range!

author: AmmoJammo
author_rank: Frequent Contributor
timestamp: June 15, 2014, 01:24:21 am
content: Doesn't seem very loud... when you overload the microphone in a camera, it stops recording the mids and highs as well

author: Flump
author_rank: Frequent Contributor
timestamp: June 15, 2014, 01:28:53 am
content: yeah a mate of mine recorded my home audio setupand the bass from the sub turned the audio to shitcouldn't even hear anything he was saying when the subwas hitting the lows and rattling me door knocker

author: zapta
author_rank: Super Contributor
timestamp: June 17, 2014, 01:26:08 am
content: WMDSent from my Nexus 5 using Tapatalk

author: Stonent
author_rank: Super Contributor
timestamp: June 17, 2014, 04:33:40 am
content: *Slight* chance of overload

author: TerraHertz
author_rank: Super Contributor
timestamp: June 17, 2014, 12:24:55 pm
content: Quote from: zapta on June 17, 2014, 01:26:08 amWeapon of Mass Distortion?The room windows didn't break. Nobody bleeding from the ears. Not good enough.

author: Legit-Design
author_rank: Frequent Contributor
timestamp: June 17, 2014, 01:03:13 pm
content: I think it needs bigger magnet and speaker coil. In proportion that's not very big when compared to some bigass subwoofers.

author: rob77
author_rank: Super Contributor
timestamp: June 17, 2014, 01:18:36 pm
content: i think the cone is way too heavy to be any goodcompare it to the regular woofers - few grams of cone, few grams of voice coil and few hundred of watts, while the woofer in the video has many kilograms of cone and 7kW of power... i wouldn't be surprised if a low-end cheap (but high power) sub-woofer would outperform it

author: M4trix
author_rank: Frequent Contributor
timestamp: June 17, 2014, 01:34:17 pm
content: I would like to see what's inside that '8kW' amplifier.

author: TMM
author_rank: Frequent Contributor
timestamp: June 17, 2014, 01:39:31 pm
content: Quote from: rob77 on June 17, 2014, 01:18:36 pmYep, this. Also the cone seemed to be supported by a rather small bush bearing on the metal pole in the center rather than being properly suspended.

author: rob77
author_rank: Super Contributor
timestamp: June 17, 2014, 01:49:56 pm
content: Quote from: M4trix on June 17, 2014, 01:34:17 pmnot too muchi assume it's a D-class power amp. so what you would find there (very simplified description) is a bridge rectifier, filer caps, a mosfet H bridge and a big ass low pass filter. the audio signal is converted to PWM and the H bridge is driven by that signal - the low-pass at the output is smoothing it out back to analog.

author: TerraHertz
author_rank: Super Contributor
timestamp: June 17, 2014, 02:47:33 pm
content: About that cone. I noticed that when it's supposed to be driving in and out, if you look at the reflections of the ceiling lights in the cone, there's a difference in how the reflections behave nearer the (lower) rim of the cone.If the cone as a whole was traveling back and forth without distorting, the light reflections should do the same everywhere on the cone.

author: rob77
author_rank: Super Contributor
timestamp: June 17, 2014, 03:39:03 pm
content: Quote from: TerraHertz on June 17, 2014, 02:47:33 pmyes, noticed that as well.. that cone is way to heavy and lacks stiffness , so instead of traveling forth and back it's just flexing. (and most of the energy is absorbed by that flexing instead of moving the air and generating sound waves )i would say those guys could have spend the many in a better wayor they should have doing more research before building it

author: jlmoon
author_rank: Unknown
timestamp: June 17, 2014, 03:53:25 pm
content: Quote from: M4trix on June 17, 2014, 01:34:17 pmlots of smoke waiting to get out!.. er.. I mean released..

author: rob77
author_rank: Super Contributor
timestamp: June 18, 2014, 02:10:18 am
content: i just noticed the rivets in the coneLOVELY !at least they should have made the cone out of carbon - less weight and much more stiffness (but the cost would go rocket high)

author: SL4P
author_rank: Super Contributor
timestamp: June 18, 2014, 02:29:20 am
content: You can see the light reflections on the cone - suggest the cone is not rigid, hence all sports of intermodulation distortion on the audio projection (let alone anything in the driver stages).Fix the cone, larger voice coil & magnet, than look at the driver.