Must try MOD - Foam inside the stamped steel baskets - YES!

Gardenstater

xschop wrote: »

Great idea. Should absorb more midrange.

Thanks. It will be fun and a way to possibly make lemonade out of lemons ha ha.

xschop

Will be one more mod that F1 will be behind on.

F1nut

xschop wrote: »

Will be one more mod that F1 will be behind on.

Gladly because I'm not into ruining other people's speakers.

xschop

F1nut wrote: »

xschop wrote: »

Will be one more mod that F1 will be behind on.

Gladly because I'm not into ruining other people's speakers.

You mean like what Polk did when they went to the plastic SL2000's?

Gardenstater

Let's put her in charge of maintaining the status quo so that someone else can take a break

plastic_avatar

So, my other 5B mw is trash, and I'm getting a new pair to go in, so this 5B mw is a test bed.

If it saves someone from making a mistake, or confirms or rejects claims/expectations, that's great! I'll be happy to contribute to the community this way.

Gardenstater

plastic_avatar wrote: »

So, my other 5B mw is trash, and I'm getting a new pair to go in, so this 5B mw is a test bed.

If it saves someone from making a mistake, or confirms or rejects claims/expectations, that's great! I'll be happy to contribute to the community this way.

Welcome and that is guaranteed to be fun.

gp4jesus

@plastic_avatar

xschop wrote: »

Dyna-Mat/butyl matting the inner frame spokes would be ok.

Yeah, ‘matting the inner spokes to add mass couldn’t hurt and could help. Don’t waste your time and ‘mat on every nook and cranny.

xschop wrote: »

My 5B PR baskets are inner-frame butyl matted. Foaming [your PR] would be unnecessary as there are no midrange reflections.

Yup

gp4jesus

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/

Gardenstater

gp4jesus wrote: »

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.

skipshot12

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…….

Gardenstater

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.

skipshot12

^
Was thinking along the lines of the manufacturing of the drivers at the beginning rather than trying to mod afterwards….

xschop

Polk's Legend drivers are wide stamped steel frames, so ours must be state-of-the-art.

Gardenstater

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

skipshot12

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?

gp4jesus

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?

in a word, yes.

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.

skipshot12

^ Thanks...

F1nut

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.

plastic_avatar

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.

F1nut

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.

Gardenstater

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.

plastic_avatar

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

xschop

There are probably more closet modders though. Happy?

There are quite a few here, and will probably remain in the closet.

pitdogg2

Black Hole 5 is a three part material. Shaving it down will get you to the hard plastic like material in the middle. Shaving it down defeats the WHOLE purpose it was made for. It works VERY well at what it was made for, to be put on the cabinet behind or to the sides of the drivers.

One way that works very well to stop a ringing basket is the cast them out of aluminum or a aluminum/magnesium material. Many companies do this.

plastic_avatar

@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.

skipshot12

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……

Gardenstater

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 🤣

skipshot12

^ Sweet
All ears here…….

xschop

Just try it out on a set of monitors first if you're apprehensive.