Anyone use hard wool felt?

Highfido

Member
2015-11-24 1:56 am
I am considering a hard felt sheet, that will function as the dust cover.

A thick veneer back. One half inch thick felt. with cutout for speakers, rectangular, with fabric cover. Closely festooning the tweet. With a horn taper.

How should this affect cross? You already ruin the sound with dust covers, so could they be designed in? Would this be useful for near field? Will it un muddy the interaction between drivers?
 

eriksquires

Member
2013-05-10 4:11 pm
I don't think you mean dust cover. Felt collects dust and pet hair like nothing else. :)

If it's something to put between the listener and the driver, no, don't do it. At most acoustically transparent grill cloth.

Do you mean you want to put felt around the tweeter? Like this from Madisound?

ring.jpg


I've had very good luck with relatively thin felt, but others promote really thick felt or foam pads which I've not tried. I haven't measured the effects, but to my ears adding felt around the tweeter improves clarity and smooths out the response. I usually cut my own from sheets like this. however you can buy them pre-cut from Madisound here.

If you prefer to make your own, you can use something like this to cut the holes out. Make sure you measure the entire tweeter hole diameter before selecting a hole cutter. Careful with metal rules! Those magnets are strong.

If you are going to measure, pay attention to the time/energy plots. If they are doing anything you should see better Cumulative Spectral Decay plots (CSD) thanks to minimizing diffraction. The thicker the felt/foam you use the more you run a risk of changing the frequency response.



Erik
 
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Highfido

Member
2015-11-24 1:56 am
I am already doing that to my ribbon tweet, with neoprene. The Focal tc120II has wool, and cheeks like the audiom tlr


https://search.yahoo.com/search;_yl...cal+audiom+tlr&fr2=sb-top-search&fr=yfp-t-201

Only the cheeks are bubinga.

As for the tweet, I had a pair of paradigm tech speaks. They INVENTED the dome tweet. They used a neoprene 2 inch thick horn loading, and backset the tweet behind the baffle. Yes, I am saying, have the dust cover function as horn loading, but to clean any interaction between drivers. And article I read, the speak designer said ALWAYS create a simple dam between the woofer and mid tweet. Then, he built felt moats around all speaks. He said, keep them non round. And so, I theorize that instead of making the dust covers inert, and better thrown away, maybe designing them in, and thus compensated for, and discouraging phase and frequency overlap interaction.
 
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eriksquires

Member
2013-05-10 4:11 pm
This is an opinion, of course, but it seems only OEM's like Wilson can get their hands on the really good Focal tweeters. Everything else uses over-taxed magnet structures more appropriate for 1/2" tweeters than 1" drivers.

As far as I know, Focal has stopped making high-end drivers (low compression, low distortion, smooth FR) available to end users, either from DIY, auto or their mid-range speakers ( < $20,000 ). Adding beryllium to crap motor structures or infinite wave damping rears to tweeters that don't need it does not make a speaker high-end to me, nor does it measure much better either except in reducing energy storage and making poor motors more effective.

Shame, I really liked the Tioxid and Audiom parts. Those old parts are worth their weight in silver I think. :)

Best,

Erik
 
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Highfido

Member
2015-11-24 1:56 am
Indeed, not all Focal is Utopian. Just utopia line. And they were tired of dumbazzs implementing their raw stuff poorly, and then badmouthing them.

I am ready to recommision my focal mini utopias. I cut a three inch thick bubinga baffle, and the utopia woofs have poor venting at that diameter without backcutting the baffle.
 

Highfido

Member
2015-11-24 1:56 am
Diffraction Doesn't Have to be a Problem

Conclusion

The examples presented here dramatically show the effects of diffraction and how it can be significantly controlled. It's very cost effective and can be aesthetically acceptable, while, at the same time, is simple to apply. I never make a baffle without edge and between-driver treatment. Try it. I think you're likely to agree. * Corrected from the original publication. The correct reference is the Society of Automotive Engineers (SAE), not to be confused with the Audio Engineering Society (AES).
 

eriksquires

Member
2013-05-10 4:11 pm
Indeed, not all Focal is Utopian. Just utopia line. And they were tired of dumbazzs implementing their raw stuff poorly, and then badmouthing them.

While I'm sure those dumbazzs exist, it seems they got tired of their own crossover developers implementing good drivers too. Hahaha. The under-damped tweeters are much harder to implement and integrate to the point where the Focal mid-range speakers hardly seem to bother. $35 SB and Vifa tweeters will probably trounce the lot.

I am ready to recommision my focal mini utopias. I cut a three inch thick bubinga baffle, and the utopia woofs have poor venting at that diameter without backcutting the baffle.

I think most drivers would have venting problems at that thickness. :)

Best,

Erik