Must try MOD - Foam inside the stamped steel baskets - YES!
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A thread on ASR that, I think, relates to our “foaming” mantra thread.
https://www.audiosciencereview.com/forum/index.php?threads/how-much-delayed-sound-comes-through-the-cone-from-the-inside-of-the-loudspeaker-in-a-closed-box.38300/
Those are the measurement guys right? I just skimmed it to see if there was any good information. A lot of them are mentioning open baffle speakers a lot as a cure, which tells me that they don't understand that reflections within the driver itself are a major problem. It is very true that most of them who build open baffle are using much better drivers than ours that do not have such a reflective design.
One guy seems to get it but didn't say much but mentioned the KEF Metamaterial. Nobody picked up on that.George / NJ
Polk 7B main speakers, std. mods+ (1979, orig owner)
Martin Logan Dynamo sub w/6ft 14awg Power Cord
Onkyo A-8017 integrated
Logitech Squeezebox Touch Streamer w/EDO applet
iFi nano iDSD DAC
iPurifier3
iDefender w/ iPower PS
Custom Steve Wilson 1m UPOCC Interconnect
iFi Mercury 0.5m OFHC continuous cast copper USB cable
Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
Custom Vibration Isolation Speaker Stands and Sub Platform -
The above has my grey matter sparking.
Why not use an angle for the spokes & bottom, inside the basket, to reflect waves away then absorb with some BH5 type of substance?
Thinking out loud again…….
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skipshot12 wrote: »The above has my grey matter sparking.
Why not use an angle for the spokes & bottom, inside the basket, to reflect waves away then absorb with some BH5 type of substance?
Thinking out loud again…….
I think that line of thinking has a lot of merit for the area between the spokes, by the spider. This is still in early development so the fun thing is to experiment. I'm trying to come up with something that is more reversible.George / NJ
Polk 7B main speakers, std. mods+ (1979, orig owner)
Martin Logan Dynamo sub w/6ft 14awg Power Cord
Onkyo A-8017 integrated
Logitech Squeezebox Touch Streamer w/EDO applet
iFi nano iDSD DAC
iPurifier3
iDefender w/ iPower PS
Custom Steve Wilson 1m UPOCC Interconnect
iFi Mercury 0.5m OFHC continuous cast copper USB cable
Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
Custom Vibration Isolation Speaker Stands and Sub Platform -
^
Was thinking along the lines of the manufacturing of the drivers at the beginning rather than trying to mod afterwards…. -
Polk's Legend drivers are wide stamped steel frames, so ours must be state-of-the-art.Don't take experimental gene therapies from known eugenicists.
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skipshot12 wrote: »^
Was thinking along the lines of the manufacturing of the drivers at the beginning rather than trying to mod afterwards….
Yeah sure. On p. 2 of this thread I posted the link to Vandersteen's patent. There are manufacturers that are onboard with this idea now. I'll look for a picture.
Scan-Speak Illuminator
https://www.scan-speak.dk/product-families/illuminator/
https://www.youtube.com/watch?v=Y5Wf0HIsvjY&t=26s George / NJ
Polk 7B main speakers, std. mods+ (1979, orig owner)
Martin Logan Dynamo sub w/6ft 14awg Power Cord
Onkyo A-8017 integrated
Logitech Squeezebox Touch Streamer w/EDO applet
iFi nano iDSD DAC
iPurifier3
iDefender w/ iPower PS
Custom Steve Wilson 1m UPOCC Interconnect
iFi Mercury 0.5m OFHC continuous cast copper USB cable
Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
Custom Vibration Isolation Speaker Stands and Sub Platform -
Gardenstater wrote: »skipshot12 wrote: »^
Was thinking along the lines of the manufacturing of the drivers at the beginning rather than trying to mod afterwards….
Yeah sure. On p. 2 of this thread I posted the link to Vandersteen's patent. There are manufacturers that are onboard with this idea now. I'll look for a picture.
Scan-Speak Illuminator
https://www.scan-speak.dk/product-families/illuminator/https://www.youtube.com/watch?v=Y5Wf0HIsvjY&t=26s
Interesting.....
That looks like a heck of a driver.
I think there's a lot to this.
Sometimes measuring equipment doesn't do justice regarding what we hear with our ears. Just because it can't be measured, yet, doesn't mean we can't hear these nuances.
I've been reading about these open baffle speakers.
Question I have is does it start to limit the amount of bass heard & felt without a box to reinforce those frequencies?
When does accuracy go too far? -
in a word, yes.skipshot12 wrote: »I've been reading about these open baffle speakers.
Question I have is: does it start to limit the amount of bass heard & felt without a box to reinforce those frequencies?
However the box’s function is to isolate the driver’s front & rear waves from each other. Another way to say it: prevent the driver’s rear wave from canceling its front wave & vice versa.
Samsung 60" QN65Q7FAMFXZA QLED, Outlaw Audio 976 Pre/Pro, Samsung BDP, Amazon Firestick, Phillips CD Changer
Canare 14 ga - LCR tweeters inside*; Ctr Ch outside
BJC 10 ga - LCR mids “Foamed” & “Plugged**”, inside* & out
8 ga Powerline: LR woofers, inside* & out
*soldered **Rob the Man (Xschop)
LR: Tri-amped RTi A7 w/Rotels*. Woofers - 980BX; Tweets & Mids - RB981*
Ctr Ch: Rotel RB981* -> Bi-amped CSi A6
Surrounds: Rotel 981* -> AR 12 ga -> RTi A3
*all connected w/Premiere ICs
5 Subs: Sunfire True SW Signature -> LFE & Ctr Ch; 4 Audio Pro Evidence @ the “Corners”
Power Conditioning & Distribution:
4 dedicated 20A feeds; APC H15; 5 Furman Miniport 20s -
^ Thanks...
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There are manufacturers that are onboard with this idea now.
That comment reminds me of the one you made about all kinds of folks putting Armacell inside the spokes of their Polk mid-drivers, which turned out to be...well, far from the truth.Scan-Speak Illuminator
Please point out where it says those drivers have sound damping on the inside of the spokes. I seem to have missed it. -
Neato damping discussions:
https://www.audiocircle.com/index.php?topic=136169.0
There have been lots of designs working to dampen baskets, and to lessen internal reflections from large basket surfaces. Foam is just another tool to try and tame a shortcoming of a cheaply made component.
I'm really curious about the difference between BH5 or wool and open cell foam on inner reflective basket surfaces.The Thrifty Setups in Mah House Big thrifty stereo in the basement w/ my custom SDA-1C (built with help from kind forum members) * Beautiful 1966 MCM GE console upgraded w/ Bluetooth, Dual turntable, and Paradigm speakers in family room * Swanky 1980 Realistic system and great TEAC eq with dancing colored lights in the living room * custom 5B on a system for my Dad * Ye Olde college stereo in the garage -
plastic_avatar wrote: »Neato damping discussions:
https://www.audiocircle.com/index.php?topic=136169.0
There have been lots of designs working to dampen baskets, and to lessen internal reflections from large basket surfaces. Foam is just another tool to try and tame a shortcoming of a cheaply made component.
I'm really curious about the difference between BH5 or wool and open cell foam on inner reflective basket surfaces.
That discussion talks about damping the outside of the basket, nothing about adding sound absorbing material to the inside. There is a huge difference.
FYI, BH5 is over an inch thick. No way in hell you'll get it on the inside of the spokes. -
Incorrect. What I said was that I had lost track of how many have done the foam inside the basket, which I realized can be confoozing as all heck. The reason people are not being forthcoming about it is that there is somehow a lot of drama being created........
After looking through the forum for mentions, I believe the number is 7 (going on 8), and no I won't name them by names. There are probably more closet modders though. Happy?
You are not following the conversation. Skip asked about building a driver from scratch that minimizes reflections inside the basket through angles and that is basically what the Vandersteen patent is all about, being a two part patent where he talks about a typical stamped basket and how absorbing materials could be used to mitigate reflections AND he introduces a design for building a driver from scratch. I believe that Scanspeak Illuminator was licensed through Vandersteen.George / NJ
Polk 7B main speakers, std. mods+ (1979, orig owner)
Martin Logan Dynamo sub w/6ft 14awg Power Cord
Onkyo A-8017 integrated
Logitech Squeezebox Touch Streamer w/EDO applet
iFi nano iDSD DAC
iPurifier3
iDefender w/ iPower PS
Custom Steve Wilson 1m UPOCC Interconnect
iFi Mercury 0.5m OFHC continuous cast copper USB cable
Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
Custom Vibration Isolation Speaker Stands and Sub Platform -
I thought the B&W approach coated the whole basket? As well as speakers like my Etons from 20 years ago? Yeah, the main goal was damping the basket.
From what I took from it, it may not affect directly reflected sound back through the cone with their coatings, but it does prevent structurally radiated vibrational sound from being created in the basket and being radiated back through the cone.And some of the coatings appear to try and absorb sound, too, rather than just add mass/density to calm vibration.
Plus, the non-stamped, thin-armed basket designs reduce reflections and emanations by virtue of their physical design.
Which is why I said, in defense of this mod (and others using materials inside and out of the basket, like Mortite), that foam is just "...another tool to attempt to tame a shortcoming if a cheaply made component.".
On BH5: I know it's thick. I'm thinking about it if it did fit, based on others' mysings. I'd happily shave it down, make an approximation in lieu of the real thing, do something, to see how a truly reflective sound killer affects the sound.
That's all
The Thrifty Setups in Mah House Big thrifty stereo in the basement w/ my custom SDA-1C (built with help from kind forum members) * Beautiful 1966 MCM GE console upgraded w/ Bluetooth, Dual turntable, and Paradigm speakers in family room * Swanky 1980 Realistic system and great TEAC eq with dancing colored lights in the living room * custom 5B on a system for my Dad * Ye Olde college stereo in the garage -
There are probably more closet modders though. Happy?
There are quite a few here, and will probably remain in the closet.Don't take experimental gene therapies from known eugenicists. -
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@pitdogg2 Jah, I know it's a Dagwood sandwich. And not easy nor likely feasible to take scrap BH5 and shave a thinner version out of it. Didn't mean to sound like I don't understand the product, just thinking out loud
I am matting the outside and inside of my 5B mw *and* foaming the interior, too. Just for fun.
The Thrifty Setups in Mah House Big thrifty stereo in the basement w/ my custom SDA-1C (built with help from kind forum members) * Beautiful 1966 MCM GE console upgraded w/ Bluetooth, Dual turntable, and Paradigm speakers in family room * Swanky 1980 Realistic system and great TEAC eq with dancing colored lights in the living room * custom 5B on a system for my Dad * Ye Olde college stereo in the garage -
I would so like to try the inside of the basket spokes mod but am too skull f-d with worrying about removal should I not like it.
If there was a triangle shaped piece that would deflect sound waves for the inside of the spokes. Something plastic? Something removable just in case it was a bad idea?
I’m also just thinking out loud here all…… -
Totally understandable why you might be nervous about doing an SRS, which is 2 x 8 drivers. The reports have only been favorable so far; 7 out of 7 people that I'm aware of. As soon as I have a functional well matched pair of MW6500s that are close in date codes I will be trying some easily reversible ideas but that won't be for a while, and it may very well change the performance. I'm going to stick with sound absorbing materials though, not deflectors.
Buckle up everybody 🤣George / NJ
Polk 7B main speakers, std. mods+ (1979, orig owner)
Martin Logan Dynamo sub w/6ft 14awg Power Cord
Onkyo A-8017 integrated
Logitech Squeezebox Touch Streamer w/EDO applet
iFi nano iDSD DAC
iPurifier3
iDefender w/ iPower PS
Custom Steve Wilson 1m UPOCC Interconnect
iFi Mercury 0.5m OFHC continuous cast copper USB cable
Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
Custom Vibration Isolation Speaker Stands and Sub Platform -
^ Sweet
All ears here…….
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Just try it out on a set of monitors first if you're apprehensive.Don't take experimental gene therapies from known eugenicists.
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So, up to 7 or 8 from maybe a few...LOL
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1C preview cross-thread report
I'll wager I foamed my baskets to a point no one else has.
Preliminary bench report from 90 hours of burn-in for caps and Wuhans is positive.
Clarity and separation is great. I can only compare to my other speakers, but I'm impressed.
They don't sound lifeless. They're quite clear, with what I feel is the proper level of 'air' around instruments and voice. Spotify Premium (which I find has distortion on sections of all my music (streaming from my old iPhone on multiple sources, that isn't on Amazon Music).
Recording was a little close, but it's just an anecdotal response. I might very well do this mod to my Monitor 12, if I keep them.
Looking forward to actually A/B'ing the mod on my 5B.
Abrupt cut at the end.
https://youtu.be/TUlij8U4oKU
The Thrifty Setups in Mah House Big thrifty stereo in the basement w/ my custom SDA-1C (built with help from kind forum members) * Beautiful 1966 MCM GE console upgraded w/ Bluetooth, Dual turntable, and Paradigm speakers in family room * Swanky 1980 Realistic system and great TEAC eq with dancing colored lights in the living room * custom 5B on a system for my Dad * Ye Olde college stereo in the garage -
Sounds great through my XS-8TLs😉Don't take experimental gene therapies from known eugenicists.
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+1 Foamed my baskets too, heard an incredible difference in detail and clarity as many others who have done the mod have reported.
Vocals are clearer, with more separation. Instruments sound like they are being played in front of me. Strings, white noise, details in tracks that I’ve not ever heard before are now coming through. The sound I hear now is nuanced and I would describe it as almost delicate.
This $0 mod (thanks to a forum member sending me the foam) really elevated the listening experience for me.
Side note - If anyone has some BH5 they wanna trade for some SL2000’s pm me?
😂Polk 7B’s modded
Velodyne CT 100
Rega Elex R
RME ADI2
Eversolo DMP A6
Pro Ject Audio Carbon Debut
Schiit Mani 2
MacBook Pro
Apple Music
Tidal -
[chuckles]
Well, if you keep giving them a listen right now as is, you can give a good comparison if you try this mod.
Warning!
For me, this was torture.
When I try to do fine motor control, I get 'essential' tremors. And this requires detail-oriented application.
The Armacel is really sticky. I used angled tweezers to set the pieces in place. I even put a thin strip of it around the top edge *below* the surround. (Doesn't impact or touch the surround at all.)
Anyhow.
Totally worth the... probably... 10 to 12 hours for me to do. Totally.
I expect a normal person to take half that time.The Thrifty Setups in Mah House Big thrifty stereo in the basement w/ my custom SDA-1C (built with help from kind forum members) * Beautiful 1966 MCM GE console upgraded w/ Bluetooth, Dual turntable, and Paradigm speakers in family room * Swanky 1980 Realistic system and great TEAC eq with dancing colored lights in the living room * custom 5B on a system for my Dad * Ye Olde college stereo in the garage -
George / NJ
Polk 7B main speakers, std. mods+ (1979, orig owner)
Martin Logan Dynamo sub w/6ft 14awg Power Cord
Onkyo A-8017 integrated
Logitech Squeezebox Touch Streamer w/EDO applet
iFi nano iDSD DAC
iPurifier3
iDefender w/ iPower PS
Custom Steve Wilson 1m UPOCC Interconnect
iFi Mercury 0.5m OFHC continuous cast copper USB cable
Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
Custom Vibration Isolation Speaker Stands and Sub Platform -
Oh G/god(s)...
Nooooooooooooooo... I *hated* that game.The Thrifty Setups in Mah House Big thrifty stereo in the basement w/ my custom SDA-1C (built with help from kind forum members) * Beautiful 1966 MCM GE console upgraded w/ Bluetooth, Dual turntable, and Paradigm speakers in family room * Swanky 1980 Realistic system and great TEAC eq with dancing colored lights in the living room * custom 5B on a system for my Dad * Ye Olde college stereo in the garage -
Not sure what your speakers sounded like before but, they sounded wonderful thru my earphones.
Well done.... -
Just so we know where this foam mod is on my end, in relation to whether or not it added negatively to how the box performs, my interior mods include:
- Armacel on all interior basket surfaces (where reachable, and in the upper ring below the surround)
- BH5 behind mws.
- Aluminized rubber pipe wrap on passive chamber walls.
- Same wrap (think of it as Dynamat lite) on exterior of all baskets.
- xschop's semi-rings on mws.
I know it's a difficult comparison, since there is no control in my observation. I'm only comparing to a similarly-structured model. And all we hear is the result of mods on a speaker with no reference.
I do know there is a definition on voices I did not expect. And right now I'm very pleased with that result.
More testing the next couple of days.
My biggest question is:
'If my speakers don't exhibit a negative with all that^, what are the chances the foam mod will mean worse sound for you?'
The Thrifty Setups in Mah House Big thrifty stereo in the basement w/ my custom SDA-1C (built with help from kind forum members) * Beautiful 1966 MCM GE console upgraded w/ Bluetooth, Dual turntable, and Paradigm speakers in family room * Swanky 1980 Realistic system and great TEAC eq with dancing colored lights in the living room * custom 5B on a system for my Dad * Ye Olde college stereo in the garage
