Anti diffraction pads on SDA's

[drumminman]

Anyone ever use the wool anti diffraction pads around the tweeters on SDA's? I think Jim Goulding makes 'em, though they're certainly DIY'able.

If so which SDA's

Thanks!

[heiney9]

Which SDA's?

If you look at the sl2500 and sl3000 tweeters they have foam/wool around the domes as part of the design. Not sure it would work properly on the sl2000. There was some discussion on the board a while back.

IIRC, it didn't really help the 13Khz spike of the sl2000.

H9

[drumminman]

2.3TL's w/ RD-0198's. My understanding is they're not so much to tame response anomalies, but more to improve imaging.

[heiney9]

2.3TL's w/ RD-0198's. My understanding is they're not so much to tame response anomalies, but more to improve imaging.

Don't think any improvement is needed, IMO. I have used the RD0194's in the Monitor 5's as well as in my 1C's the imaging is superb.

Give a try and report back with your findings.

H9

[heiney9]

Are you having some imaging problems?

H9

[Joe08867]

I have used them on other speakers AR and Advents to try but never thought the SDA's or older polks ever really needed the help.

[drumminman]

Are you having some imaging problems?

H9

No, just wondering.

Such a cheap tweak, and other non SDA owners report a positive effect.

[VR3]

Im the SDA design would use it to a benefit - the enclosure is ultra wide and it basically removes all the initial reflections around the tweeters.

It made a world of a difference on my Super Towers..

[drumminman]

Im the SDA design would use it to a benefit - the enclosure is ultra wide and it basically removes all the initial reflections around the tweeters.

It made a world of a difference on my Super Towers..

That's kinda what I'm thinking - more benefit on speakers with a wide front baffle. I know McMasters-Carr had wool felt - may have to try it and report back.

[VR3]

Wilson does their entire baffle, even around woofers in that same diffraction be gone material - real thick wool or whatever

I would love to have an entire sheet cut for the front of my speakers but it would look hideous lol

[heiney9]

On multiple tweeters with the progressive point source (which is specifically to increase dispersion and limit diffraction) would you use it on all the tweeters? The one with the most output? Least output? Or a sheet around the entire area of the tweeters?

Remember we are not dealing with a single tweeter with a single point source (although the progressive point source acts as a single point source).

Just curious what you are thinking?

H9

[heiney9]

I would love to have an entire sheet cut for the front of my speakers but it would look hideous lol

Who cares what it looks like, it's about the music, right?

[VR3]

I would put it around every tweeter personally - it really makes a difference...

And man I can deal with the little bit around the tweeter but anything else, bah -

Now if my speakers were built like Wilson and the pad was recessed into the cabinet versus held on by glue or velcro - I may feel differently...

[drumminman]

Since the tweeters are so close together I was thinking about doing the center cut out to surround them together, with the outside part extending to the MW's.

IIRC the stuff isn't too expensive so I'd probably try doing each tweeter individually too to hear if there's a difference.

[heiney9]

I would put it around every tweeter personally - it really makes a difference......

So you've used it with success on SDA's and other Polk's? Please elaborate

H9

[inspiredsports]

. . . on multiple tweeters with the progressive point source (which is specifically to increase dispersion and limit diffraction) would you use it on all the tweeters? The one with the most output? Least output? Or a sheet around the entire area of the tweeters?

Remember we are not dealing with a single tweeter with a single point source (although the progressive point source acts as a single point source).

Just curious what you are thinking?

H9

I'm also curious about thoughts on single point source SDA 2B, CRS, etc.

[heiney9]

I say go for it and do a thorough analysis before and after.

H9

[DarqueKnight]

Anyone ever use the wool anti diffraction pads around the tweeters on SDA's? I think Jim Goulding makes 'em, though they're certainly DIY'able.

If so which SDA's

Which SDA's?

If you look at the sl2500 and sl3000 tweeters they have foam/wool around the domes as part of the design. Not sure it would work properly on the sl2000. There was some discussion on the board a while back.

IIRC, it didn't really help the 13Khz spike of the sl2000.

2.3TL's w/ RD-0198's. My understanding is they're not so much to tame response anomalies, but more to improve imaging.

Since the tweeters are so close together I was thinking about doing the center cut out to surround them together, with the outside part extending to the MW's.

IIRC the stuff isn't too expensive so I'd probably try doing each tweeter individually too to hear if there's a difference.

The SL3000 tweeter had a felt ring around the dome, but the RD0198 silk dome replacement did not. I'm thinking the fabric dome tweeters don't need felt surrounds to provide the "help" that the plastic dome tweeters did.

Only Polk's engineering department knows for sure.

[VR3]

I have not used them on the SDA - but the theory behind the diffraction pads on SDAs make sense - particularly taking into account the blocky grill design...

I have tried them on several speakers I do have with positive results... I would give it a shot at a minimum

[heiney9]

The only reason I asked is because the SDA's give a completely different presentation compared to a more "normal" design. I agree, the only way to find out is to try it. I hope drumminman does a really good analysis before and after or it's really not worth reporting about.

H9

[drumminman]

The SL3000 tweeter had a felt ring around the dome, but the RD0198 silk dome replacement did not. I'm thinking the fabric dome tweeters don't need felt surrounds to provide the "help" that the plastic dome tweeters did.

Only Polk's engineering department knows for sure.

Interesting. When I got my 2.3TL's they had no felt rings around the tweeters, didn't look as though they had been there and then been removed.

FYI I googled felt and the 100% pure wool felt, which is supposed to be the stuff that works best (no synthetics or blends), is $35/sheet from MC, estimated two sheets needed.

So I sent an email to the maker of diffraction be gone pads to get a price estimate.

Stay tuned for As The Wool Turns. . . . .

[heiney9]

Interesting. When I got my 2.3TL's they had no felt rings around the tweeters, didn't look as though they had been there and then been removed.[/I]

If they were shipped with sl3000's they had to have the felt ring. If you aren't looking for it, it's very easy to miss since it blended so well.

H9

[heiney9]

The very first page of this color brochure clearly shows the ring of felt around the dome of the sl3000.

http://s4l.co/polk_audio_brochures/polkaudio3.pdf

[F1nut]

I tried some variation of anti diffraction pads on my SDA's. Didn't do anything that I could tell.....long gone now. But, don't let that stop you from trying it yourself.

[drumminman]

The very first page of this color brochure clearly shows the ring of felt around the dome of the sl3000.

http://s4l.co/polk_audio_brochures/polkaudio3.pdf

Yeah, I may have missed 'em. I was thinking the rings were much larger. They're boxed up -I'll take a look when I get home.

[drumminman]

I tried some variation of anti diffraction pads on my SDA's. Didn't do anything that I could tell.....long gone now. But, don't let that stop you from trying it yourself.

Did you have the RD-0198's or the SL3000's when you tried 'em?

[heiney9]

Yeah, I may have missed 'em. I was thinking the rings were much larger. They're boxed up -I'll take a look when I get home.

It is very easy to do because they blend so well. This is one quick and dirty way to tell the sl2500/sl3000 from the RD0's if one is looking to buy some speakers and are unsure which they have. There are obviously other things to look for too, but just one look for the felt/foam ring gives it away.

H9

[Fongolio]

I bought my SDA-1C's off Geoff727 in Seattle and he used a type of felt. I've never heard SDA's without it so I can't give a comparison. I can, however, tell you that these speakers have a gigantic wide and deep soundstage and image beautifully. Pic attached. Notice also the beautiful Paduk caps Geoff fitted to them.

[F1nut]

Did you have the RD-0198's or the SL3000's when you tried 'em?

The SL3000's.

[geoff727]

Attachment 65058I bought my SDA-1C's off Geoff727 in Seattle and he used a type of felt. I've never heard SDA's without it so I can't give a comparison. I can, however, tell you that these speakers have a gigantic wide and deep soundstage and image beautifully. Pic attached. Notice also the beautiful Paduk caps Geoff fitted to them.

I was just about to chime in and saw that picture! Anyway, here's another one. Same speaker, showing a closer view of the anti-diffraction felt. To answer the question of what difference it made.....I don't know, I did about a hundred changes all at the same time, if I remember.

G~