Floating speaker enclosures - Page 3 - diyAudio
Go Back   Home > Forums > Loudspeakers > Full Range

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 13th June 2013, 06:09 PM   #21
stevieg is offline stevieg  United Kingdom
diyAudio Member
 
Join Date: Nov 2009
Location: Gwynedd North Wales
Roksan used to have a spring suspended tweeter on an OB, if my damaged memory still functions....Don't think it went into production though. The thinking was to isolate the tweeter from the bass vibes.

Cheers Steve
__________________
steve
if it ain't broke, I ain't fixed it
  Reply With Quote
Old 14th June 2013, 05:56 AM   #22
diyAudio Member
 
picowallspeaker's Avatar
 
Join Date: Apr 2007
I'm in the making of a spring suspended 3 way, very easy and also OB.
Not springs but rubber bands because the springs introduce some mechanical noise;
and not OB but some U-frame to let the back wave estinguish slowly without making
too much harm ....
  Reply With Quote
Old 15th June 2013, 04:19 PM   #23
diyAudio Member
 
Overkill Audio's Avatar
 
Join Date: Oct 2006
Default Suspended drivers - 3 way - open baffle

Hi Guys,

I made these in 2010... Still love the sound but not got the space anymore.

I think suspended drivers work best in open baffles.
The attached used a Beyma SM115K 15 inch bass, Precision Devices PD 158 15 inch low midrange and the Manger driver above 500Hz.
Battery powered DEQX run all Eq and crossovers.
The 15 inch drivers were suspended on soft polyprop cord from wooded dowels.
The drivers were not bolted in place, they were suspended a few millimetres away from the rear of the baffle and then pushed gently against the baffle via Sorbothane blocks. Large sorbothane gasket in front of the speaker chassis and Sorbothane blocks behind it, the driver itself never touched any surface of the baffle.
The baffle was birch Ply and MDF, the front baffle was CNC'd out of 75mm thick MDF, the rest was all cut from 12mm birch.

The 15 inch driver are both rather special, really effortless and natural and also capable of filling a large room with powerful music...110dB peaks at the (4meter) listening position!
Even at max party volumes the cabinets were inert, no nasty panel vibrations induced from the drivers. Its hard to more definitive because every surface in the room was being energised by the sound energy i.e. sofa tables, walls etc. but the sound stage remained stable.

Bottom line is this method ( or similar suspended & open baffle combo's) is the only method I am aware of that TOTALLY eliminates all cabinet resonance and effects.
You can eliminate cabinet resonance by CNC' ing cabinets from solid blocks of alloy / phenolic resin / synthetic stone etc and get 200Kg non resonant "containers"...
BUT you still have all the usual internal reflections bouncing around and then emerging out through the cone ( out of phase) sonic problems...

You can go open baffle and get rid of the internal resonance, but you still have cabinet resonance....

Only combining Open Baffle and fully isolated / suspended drivers will let you hear the drivers and crossovers without and cabinet distortions.
Cheers
Derek.
Attached Images
File Type: jpg 005 (Copy).JPG (104.6 KB, 293 views)
File Type: jpg 045.jpg (507.8 KB, 260 views)
File Type: jpg 678.jpg (575.5 KB, 247 views)
  Reply With Quote
Old 26th June 2013, 08:27 AM   #24
diyAudio Member
 
picowallspeaker's Avatar
 
Join Date: Apr 2007
Quote:
Originally Posted by Overkill Audio View Post
Only combining Open Baffle and fully isolated / suspended drivers will let you hear the drivers and crossovers without and cabinet distortions.
Cheers
Derek.
And how do you achieve that ?

Ps. And 'bouncing' is the key ...
Attached Images
File Type: jpg DSCN2919.JPG (232.4 KB, 216 views)
File Type: jpg DSCN2920.JPG (286.1 KB, 215 views)

Last edited by picowallspeaker; 26th June 2013 at 08:32 AM.
  Reply With Quote
Old 29th June 2013, 03:49 PM   #25
diyAudio Member
 
Join Date: Jun 2009
Quote:
Originally Posted by picowallspeaker View Post
And how do you achieve that?
I did it this way. Stig Erik's build may also be of interest, though neither his build or mine is optimal in that no real effort's made to obtain torque balance---if one seeks to minimize parasitic vibrations the ideal motion is purely linear translation in response to soley cone thrust, which requires zero net torque in order to avoid any rotational components. This is why all my hangs are pantograph-like. I can't really say if the likeness is good enough but neither is it poor; THD is below my -50 to -55dB measurement noise floor. The distortion increase from decidedly off balance configurations is measureable easily enough.

With a full range some sort of rear wave control is required for adequate SPL, which in turn means some kind of baffle, box, pipe, or what have you. Full range implementations tend to be better about avoiding box pressurization and associated internal vibration sources than multiway---more BVRs, horns, TLs, and such in full range with more attention paid to stuffing, compliance volumes, and other forms of resonance control. If one, for a moment, assumes panel vibrations and such aren't an issue, this leaves the problem of the driver axis is rarely aligned with the enclosure's center of mass. This produces a torque imbalance and so the speaker will tend to rotate when hung. I rather suspect the resulting distortion will generally be negligible, though, most enclosures being heavy compared to the few grams of moving mass in a typical full range driver. Given the smallness of the angular deflections and compliance of typical speaker supports (flooring or shelves) it wouldn't surprise me if it turned out there's no measureable difference between hanging and normal placement in this regard. Similarly, it would surprise me if hanging did anything to mitigate cabinent vibration caused by pressurization.

There does seem to be benefit in providing low order modes which accomodate driver thrust. Linkwitz and others have found supporting a driver near its center of mass rather than from its mounting flange reduces basket and enclosure vibration. My own experience is similar, having been able to produce measurable acoustic artifacts from support structures which seemed solid but turned out to have resonance problems until the drivers were decoupled by hanging or other means. It is my hunch the majority of cabinet vibrations are produced by mechanical coupling to the driver rather than acoustically generated but I've not seen data on this.

Since most full rangers use unsealed cabinets there's no strict requirement for a tight seal around the driver. mige0 did a hanging dipole build a few years ago with a 300mm driver hung such that it was centered in a 305mm hole in baffle which was also hung, yielding a small air gap all the way around driver. One could easily bang out a couple simple full range MLTLs and try something similar; attach the driver with screws as usual one as a control and hang the driver from within the enclosure to align with its hole in the other. Measure the two and see if there's a detectable difference. If anyone had an old MLTL pair lying around they weren't using and didn't mind modifying that would make the experiment super easy.
  Reply With Quote
Old 29th June 2013, 05:35 PM   #26
diyAudio Member
 
picowallspeaker's Avatar
 
Join Date: Apr 2007
I didn't explain how it works ( apart from those silly experiments that you mentioned about placing the speaker very near to the hole and such things like OB that don't take into account that what the driver produce with the back radiation is the negation of what it emits frontally....)
the trick is to make the speaker ( or sub-part of it, since each driver works in a dedicated-specialized band) able to move but out of working band.
That is achieved with rubber bands, which are springs, and they must be tensioned till the load ( the speaker, or the cabinet as a whole) can oscillate at subsonic frequency. This basic principle might (....) be extended to the whole system.
  Reply With Quote
Old 29th June 2013, 06:19 PM   #27
diyAudio Member
 
Join Date: Jun 2009
If by out of band motion you're referring to the decoupling which occurs above a suspension's resonant frequency that's trivially acheived with rather short pendulums, be the members rigid or no (small displacement formula's here; for a 100mm pendulum the frequency's a rather thoroughly subsonic 1.6Hz). I agree pendulum baseed decoupling can be constructed with rubber bands as members (or any number of materials) but am unsure what vibration mitigation benefit the elasticity of a tensioned spring positioned more or less orthogonal to the piston axis offers; can you be specific as to the method of operation?

I think if you review open baffle design you'll find considerable awareness of cancellation between front and back waves. Try here for a start. For small gap decoupling I've used the superposition method discussed here; if you check it out you may find it's less silly than you thought.
  Reply With Quote
Old 29th June 2013, 07:15 PM   #28
diyAudio Member
 
picowallspeaker's Avatar
 
Join Date: Apr 2007
I don't model and I don't measure. Rubber bands are cheap
  Reply With Quote
Old 15th October 2013, 08:57 PM   #29
diyAudio Member
 
Overkill Audio's Avatar
 
Join Date: Oct 2006
Default Suspended or " Flying " drivers

Twest is right....

There is a lot of good "peer reviewed" (some of the big brains on this site!) explanation of the maths and physics behind this principal.
Its actually counter intuitive, I couldn't believe that a " suspended" 15 or 18 inch Pro driver would not start swinging around when pumping 500 watts of low synth bass through it....
It just sounds really really clean with great punch and dynamics....The exact opposite of what I thought it would sound like.

If you have the money & space...Imagine a DEQX or good DSP crossover Eq package running the crossovers.
Add a 15 or 18 inch Pro bass, a 6 or 8 inch midrange and a Beyma TPL tweeter all suspended by their magnets on soft poly prop cord from a light but rigid alloy space frame. Each driver has a 20mm Neoprene gasket on the front side of the chassis.
The assembly is free standing in your listening room, nice sound but no bass and thin low midrange.... Now slide up a beautiful trapezoid custom GRP baffle with VPL sides, all curved and flowing to allow correct time alignment of the drivers. The baffle mates up perfectly with each driver gasket just touching the inside of the baffle.
Suddenly its a very very different sound, Zero cabinet colouration, each driver working in its ideal pass band, some of you will know what I mean!!

Especially Mige0 and Stig Erik, they both developed very good suspended designs.
Have a site search, the posts from these guys are really great, very educational and Stig Erik builds prototypes at a hell of a pace!

Hope this sparks some research into this massively under exploited concept.
Cheers
Derek.
__________________
" This is not the end, not even the beginning of the end, but it is the end of the beginning "
Sir Winston Churchill 1943
  Reply With Quote
Old 15th October 2013, 09:22 PM   #30
sayrum is offline sayrum  Germany
diyAudio Member
 
Join Date: Jun 2011
Just an idea: a
Speaker is made up of moving and stationary parts/components. Afaiu the moving parts need a solide/stable base/"setting" (the stable parts) to preform their function correctly -> so suspending speakers kind of defeats that.
Seems to me one creates a "swinging/unstable system with its own resonance. Not a good idea i think.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Regulator with floating ground and speaker protection PauloPT Solid State 3 3rd March 2013 12:10 AM
Ideas on Speaker Enclosures... enigmaticEntity. Multi-Way 3 5th November 2009 05:56 PM
Speaker Enclosures FrankRoss Multi-Way 3 13th September 2006 08:54 PM
Speaker enclosures. pixie Multi-Way 5 31st January 2003 12:33 PM


New To Site? Need Help?

All times are GMT. The time now is 08:54 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2