speakers operating near their resonant frequency

[planet10]

I also experienced the Sokol adjustable transform for closed speakers.

Is that similar to or the same as a Linkwitz transform (which i forgot to mention in my earlier post)

dave

 

[kanguru007]

There are some new pretty effectibe damping materials available... This is one that has popped up a couple times that looks interesting. http://www.eltim.eu/index.php?action=extra&extra=new_twaron__angel_hair__damping_material&lang=EN

Thanks! I was looking for something that worked well and was not as nasty as fiberglass. Only the sentence "...since not all is measurable as we know with cables..." makes me stutter.

Since the box is sealed, a high Q bass is simply a matter of too small a box. Adding stuffing increases the apparent volume of the box but only 20-30% maximum,
KEF has just patented a technique that uses activated charcoal to take the idea further.

Googling about activated charcoal I found a thread about perlite on this site:
http://www.diyaudio.com/forums/showthread/t-84690.html
But the messages stop before they do any real tests.

What i usually do in a situation like this is to make the box aperiodic (the damped series of small holes mentioned above)

When I don't close the balls carefully and they're not airtight they lose their punch. I think the cloth surround woofers in these speakers depend on the internal enclosure air pressure to work correctly. Anyway I'd feel bad drilling holes in 1969 speakers.

 

[kanguru007]

That sounds very excessive. How are you testing to get this result?

I hit pause on the CD player during a bass-intensive part and the subwoofer just continued boooooommmmiiinng. I thought it was the room so I tested again outside.

 

[forr]

Is that similar to or the same as a Linkwitz transform (which i forgot to mention in my earlier post)

dave

Hi Dave,

Yes but more simple and adjustable. Here is the schematics of an enhanced version from Hegglun. For me it worked impressively with a B&O Beovox S45 (8' bass Peerless) driver in a little room.

 

[planet10]

Thanx. That could be useful...

dave

 

[kanguru007]

Hi Dave,

Yes but more simple and adjustable. Here is the schematics of an enhanced version from Hegglun. For me it worked impressively with a B&O Beovox S45 (8' bass Peerless) driver in a little room.

The frequency of the filters in this circuit must be adjusted to match the speakers, right?

 

[sreten]

Hi Sreten,
Negative resistance can be easy to implement.

Hi,

Not for driving a full range multiway speaker, you need to only
have negative impedance in the bass then returning to normal.

🙂/sreten