A couple of folks have suggested that bolting a driver to the baffle would stiffen / damp the driver frame, and prevent ringing. A couple of stamped frame drivers I have used so far (TB W3-871s and Fostex FE167E) have had rolled edges on the front of the frame. This means that only the edge of the front of the frame and perhaps indentations around the screw holes are actually in contact with the speaker baffle. A large portion of the exposed front of the frame contacts nothing, and is free to ring.
chops,
Exactly those two and a vast ocean of others of so subtle a nature that are easily obscured by all of the internal and external reflections and standing waves, both systemic and transitory found in so many speaker systems.
I find it fascinating to discover just how stupidly good our recordings are, even when set in red book! The issues raised with lack of proper ground planes in modern commercial equipment, the interaction of dielectric materials and copper wire in cables, all of these bear upon how much of this information is retained. However, the speakers are so important to this chain that I think everyone who is interested in deeply detailed and intuitively correct playback of music should spend either the time or the relatively small amount of money needed, to obtain a pair of these "large scale dynamics" challenged full range speakers, to explore the other end of that dynamics scale.
Bud
Exactly those two and a vast ocean of others of so subtle a nature that are easily obscured by all of the internal and external reflections and standing waves, both systemic and transitory found in so many speaker systems.
I find it fascinating to discover just how stupidly good our recordings are, even when set in red book! The issues raised with lack of proper ground planes in modern commercial equipment, the interaction of dielectric materials and copper wire in cables, all of these bear upon how much of this information is retained. However, the speakers are so important to this chain that I think everyone who is interested in deeply detailed and intuitively correct playback of music should spend either the time or the relatively small amount of money needed, to obtain a pair of these "large scale dynamics" challenged full range speakers, to explore the other end of that dynamics scale.
Bud
AdamThorne said:
And why would this not stop bell modes? Take a crystal wine glass. Tap it with a spoon. RING! Turn the glass over and press the opening into the table. Tap it. thud.
A bell rings only because there are no boundary constraints at the mouth. Lock down even part of the lip of a bell and it won't ring.
Are you suggesting that the flange is flexing?
Bob
And why would this not stop bell modes? Take a crystal wine glass. Tap it with a spoon. RING! Turn the glass over and press the opening into the table. Tap it. thud.
I actually just did this, and a few variants on it.
Most ringing -
glass, free air
glass, upside down on tile table
glass stuffed with a hat, on a fluffy scarf on table
glass upside down on a fluffy scarf on table
glass stuffed with a fleece hat upside down on table
glass on a quarter inch of newspaper on table
glass stuffed w/ hat on quarter inch of newspaper on table
- least ringing
A few thoughts on the results:
- a different way of thinking of various materials between the resonant object may be to consider an impedance barrier between the driven object and mechanical ground. I'm not sure if there is anything to be gained by thinking of the phenomenon in this way.
- I think the fluffy scarf allowed sound from the inside of the glass to be heard on the outside, generating a more audible strike even if it was better damped.
- There seemed to be 2 different aspects of the noise of striking the glass 1) clarity of pitch 2) rate of decay. Some conditions resulted in fast decay but still a clear pitch. The resulting impression was of relatively high audibility.
- damping isn't a yes/no issue. Given that your speaker frame is continuously driven I figure you probably want the best damping / mechanical grounding you can get.
I actually just did this, and a few variants on it.
Most ringing -
glass, free air
glass, upside down on tile table
glass stuffed with a hat, on a fluffy scarf on table
glass upside down on a fluffy scarf on table
glass stuffed with a fleece hat upside down on table
glass on a quarter inch of newspaper on table
glass stuffed w/ hat on quarter inch of newspaper on table
- least ringing
A few thoughts on the results:
- a different way of thinking of various materials between the resonant object may be to consider an impedance barrier between the driven object and mechanical ground. I'm not sure if there is anything to be gained by thinking of the phenomenon in this way.
- I think the fluffy scarf allowed sound from the inside of the glass to be heard on the outside, generating a more audible strike even if it was better damped.
- There seemed to be 2 different aspects of the noise of striking the glass 1) clarity of pitch 2) rate of decay. Some conditions resulted in fast decay but still a clear pitch. The resulting impression was of relatively high audibility.
- damping isn't a yes/no issue. Given that your speaker frame is continuously driven I figure you probably want the best damping / mechanical grounding you can get.
G'day,
I have used a 3/8" threaded rod as a "pressure screw" between
the back of Voigt pipes and the magnet of an RS-1354A driver.
It did make an audible difference which in part would be due to
the effect of stiffening the cabinet.
On my FE167E's, I don't use the pressure screw, but covered the
magnet and legs with blue tack and filled in the cavity in the
bezel as well.
There is an audible difference to me between before blue tack
and after with no other changes made.
Cheers,
Alex
I have used a 3/8" threaded rod as a "pressure screw" between
the back of Voigt pipes and the magnet of an RS-1354A driver.
It did make an audible difference which in part would be due to
the effect of stiffening the cabinet.
On my FE167E's, I don't use the pressure screw, but covered the
magnet and legs with blue tack and filled in the cavity in the
bezel as well.
There is an audible difference to me between before blue tack
and after with no other changes made.
Cheers,
Alex
Bob Brines said:
Everything rings. Just a question of how much, how damped, and at what spectrum.
dave
I'm not affiliated with any of these products.
I checked SR500 here in Victoria BC and retail is $115 plus tax for what looks like a 3.94 liters/1gallon. (ouch)
Anyone want to split a gallon, maybe 3 ways? local ish.
Spectrum sludge looks promising anyone in car audio get their hands on it? There's a dealer in Surrey (isn't there always) and 1 in Quesnel
http://www.secondskinaudio.com/sound-deadener/spectrum-sludge.php?category=121
*Apply with a Brush or Putty Knife
* Includes Cryogenically Treated Polymers (heh, fun!)
* Cleans up with Water
*Non Toxic
*Odor Free Once Cured
eDead V3 looks moderately promising, another car audio product and less expensive
http://www.edesignaudio.com/product_info.php?products_id=53
I have been looking at other substances, like Marine Tex waterproof epoxy, NoMoreNails, a couple different epoxies and rubber rocker guard.
So far, rubber rocker guard is probably closest cheap alternative but is very odoriferous, toxic and takes a long time to setup/off gas enough for indoor use. Same with rubber based roof patch.
I checked SR500 here in Victoria BC and retail is $115 plus tax for what looks like a 3.94 liters/1gallon. (ouch)
Anyone want to split a gallon, maybe 3 ways? local ish.
Spectrum sludge looks promising anyone in car audio get their hands on it? There's a dealer in Surrey (isn't there always) and 1 in Quesnel
http://www.secondskinaudio.com/sound-deadener/spectrum-sludge.php?category=121
*Apply with a Brush or Putty Knife
* Includes Cryogenically Treated Polymers (heh, fun!)
* Cleans up with Water
*Non Toxic
*Odor Free Once Cured
eDead V3 looks moderately promising, another car audio product and less expensive
http://www.edesignaudio.com/product_info.php?products_id=53
I have been looking at other substances, like Marine Tex waterproof epoxy, NoMoreNails, a couple different epoxies and rubber rocker guard.
So far, rubber rocker guard is probably closest cheap alternative but is very odoriferous, toxic and takes a long time to setup/off gas enough for indoor use. Same with rubber based roof patch.
MichaelPublic said:
Mixharl.. i just bought another gallon on Friday... bring your own container you can take away as much as you need, A gallon does something on the order of a 100 FE12x.
dave
planet10 said:
Dave, I woukd be happy to CNC some mounting plates for you.
FREE
Now you may ask why would i do this?
Because you and many, many others here share great experience and knowledge. I have learned a great deal on this site. This is in some way my part of giving something back.
jim
max426 said:Dave, I woukd be happy to CNC some mounting plates for you.
FREE
I will take you up on that... i'll have to think about, and consult with Chris about where best to use the gift... very much appreciated.
email me so as to establish contact.
dave
MJL21193 said:All of that highly accurate, scientific testing is the hallmark of these threads.
Way to be a downer. Simple empirical tests like the one he did are a very useful way to build a knowledge base, and play with what works for a given application. First hand experience trumps anything else, as it gives you a framework into which you can fit and apply theory. XYZ works, and there is ABC theory.... Oh, I see, periphery damping suppresses...... that explains why when I press on the edge....
Why take the extreme anti-subjective stance? Observation is part of scientific process.
Late to this thread:
From the 70's to about 96 I used Silicone RTV on the frame ribs.
In the Speaker Builder 5/96 issue the article: The Opposite Moduli (OM) Speaker Cabinet - featured experiments with amalgams mixtures.
Using this as a strategy, I switched to a mixture of clean fine sand and Rosco FlexBond.
This is extremely inexpensive and sticks to inside of sub woofer panels as acoustic dampening, and as an acoustic mastic on other surfaces.
From the 70's to about 96 I used Silicone RTV on the frame ribs.
In the Speaker Builder 5/96 issue the article: The Opposite Moduli (OM) Speaker Cabinet - featured experiments with amalgams mixtures.
Using this as a strategy, I switched to a mixture of clean fine sand and Rosco FlexBond.
This is extremely inexpensive and sticks to inside of sub woofer panels as acoustic dampening, and as an acoustic mastic on other surfaces.
Dave, I'm curious as to whether this treatment has any effects on heat retention of the voice coil. I wonder whether encasing the magnet assemby and such prevents heat from dissipating at all?
I'd like to hear anyone's thoughts on this as it is the only real apprehension I have before trying this, or similar, treatments out.
I'd like to hear anyone's thoughts on this as it is the only real apprehension I have before trying this, or similar, treatments out.
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