[bastardbus]

So I have been in the process of fixing up a really nice original Philco 80.  The original speaker cloth was intact but starting to deteriorate.  So I purchased a new reproduction piece of the small Richmond small herringbone.  The material looked wonderful so I installed it today and am having a severe issue of the material buzzing or vibrating against the wood of the cabinet.  Even at very low volumes you can see the material bounce with the sound coming from the speaker!  At louder volumes it just sounds horrible....Buuzzzzing and rattling.  And it NEVER did this before I replaced the material, the speaker sounded great.

I took a closer look at my now removed original and the reproduction stuff.  The original was quite thin and you could easily blow through it thus great for sound waves traveling through it.  I tried the same thing with a left over piece of the repop stuff and WOW...I could barely blow any air through it at all, it was like blowing into a bag!  Air does NOT travel through it at all!  EEEkkkk  not good.  Apparently the new material does not have very good acoustical transferring properties and acts like putting a sheet of paper over your loud speaker.

So now I have removed my original material and almost destroyed in and have a restored radio I can't listen to because it sounds so horrible with this new speaker cloth on it.

Any suggestions or other folks on here have had this issue?

I might take a video of the unit playing with this material....you can actually see the speaker cloth bouncing back and fourth with the sound as plain as day even at mid level volumes!  It is ridiculous.

Bummed out....

[klondike98]

hmmm...strange. I've used the same material from Kenneth and have not seen or heard that problem. I use 3M's 77 spray adhesive on the mounting board, let it get tacky and then lay down the cloth at one end and snug it firmly as it goes down so it taut across the speaker opening. I use the hot soldering iron to poke a hole through any place a bolt needs to go through.

Is it just the cloth making the noise or is the mounting board also rattling?

[Eliot Ness]

After the glue dries I also lightly spay the cloth with a light mist of water, then hit it with a blow dryer and it pulls it even tighter..... maybe that will help. 

[bastardbus]

Hi Guys,

I followed Ken's directions to the T.  Besides I have done vintage auto restos for a living the past 20 years and have done more vintage cloth headliners and reupholster jobs then I can count, so it's not my first dog show with this kinda thing.  We buy 3M 77 by the case from B&W paint here in Toledo if that says anything. 

The material looks GREAT and is tight as a drum and the buzzing or rattling is definitely NOT the speaker board or the cabinet alone but the material buzzing or vibrating against it.

A couple more points.
-I had been running the unit for a week or so with the old grill cloth and ZERO problems like this.
-I pulled the speaker out and played it loose from the cabinet and ZERO buzzes or rattles from the speaker.  No voice coil rub nothing.  The speaker is mint mint mint too.
-mounted the speaker minus the grill cloth and it works beautifully no buzz of noise.

As I mentioned this cloth is almost impermeable to air blowing through it.  That is obvious just comparing it to the original which is very porous and thin.  Trying to blow through the new cloth is almost impossible.  What I think is happening is there is such an air tight seal between the speaker-board-cabinet and now this new material there is no vent (or very little) for the air pressure caused by the speaker moving in and out to go.  You can see the facbric bouncing in and out just like a speaker cone...I have never seen anything like it! LOL  I even showed my wife and she was shocked.  I am actually somewhat worried it could cause damage the original speaker.

I am going to try a couple things this evening.  One lifting the speaker off the mount board with some small spacers to see if giving the speaker a vent fixes the issue.  If it does I will go from there and either find a different fabric or use my old original.

One question to the poster above, what model did you use this fabric on?   Was it the small herringbone or just some of Ken's materials.  Reason I ask is the model I used it on (Philco 80) has an extremely small area between the speaker and the material.  Maybe a radio with a much larger air space in front of the speaker is more forgiving.

I am 99% sure this issue is do to the material being too dense to allow proper air flow from the speaker moving in and out but need to verify that and then figure out what to do about it.

T

[Kenneth F. Besso Jr.]

  I bought the same stuff,,,NOO problem with it,,,,I did not make it tight,,,only glue on back side of speaker board (elmers white) works great,,,received from same person,,same pattern( small Herringbone) for my Philco 80 jr. 

[bastardbus]

I'll post a video so ya'll can see-hear it in a bit.

Mine was attached snug-tight as per Ken's exact directions....maybe it is too tight?  Never thought that would be a problem though...

T

[bastardbus]

Here is a couple videos of the issue.  

First video is short but you can really hear the issue
https://www.youtube.com/watch?v=5O7y7qagKdw

It was very difficult to capture the cloth moving in and out but if you watch closely in the first video you can see it best around 00:32 until the end.  It is far more drastic then the video captures, my wife even noticed immediately and that is saying a lot... LOL  The buzz is quite clear and it is usually at certain lower frequencies.  Again it sounds like a buzz, you should be able to hear it.  Again, everything is tight, in place and installed correctly.  I have went over the thing 100 times nothing is loose.  I have also run the unit with the speaker out on the table and the speaker cloth removed and just the bare baffle and there is NO buzz under those conditions.

I deal mostly in `50s era hi-fi stuff and there are volumes upon volumes of books written just on speaker cabinet design>  They discuss the importance of proper ports, air flow, internal size, how to tune the cabinet to certain frequencies, etc  ect.  

What I think is happening here is with this new fabric is far more restrictive about air flow then the original was, and thus it is causing the cabinet - baffle to resonate at certain frequencies where it did not before.  As mentioned if I remove the grill cloth and run the radio with just the speaker and baffle it sounds wonderful and I can turn the volume full blast without any buzz or issue. The speaker is mint, no tears, no voice coil rub, no loose gasket, magnet or coil, but as I said it works perfect without that grill cloth installed.

I took a break from the Philco tonight and worked on re-capping a `57 RCA SHF-4 for a fellow down in Mexico.  I am pondering some small shims between the speaker and baffle but leaving a small air port open to see if it cures the problem and will try that next tomorrow eve.  Meanwhile if anyone has any ideas please let me know.

Thanks
Todd

P.S a Longer video playing a few channels but you can hear the issue on different channels and see how annoying it is.  The bad thing is I really enjoyed listening to this little guy the last two weeks and now I can't stand it because of the constant buzz...
https://www.youtube.com/watch?v=KL_6SVn9OIw

[Eliot Ness]

Have you talked to Kenny about it yet?  Maybe your piece came from a new batch and he didn't notice how dense it was.

[morzh]

I would talk to Kenny first. If there is a problem, I am sure he will correct it and make it right. He would not be interested in selling stuff that does not work.

[bastardbus]

I would talk to Kenny first. If there is a problem, I am sure he will correct it and make it right. He would not be interested in selling stuff that does not work.

I sent him an email with vids seeing what he thought...

T

[bastardbus]

Received a reply from Ken and it was on par with the many threads I have read on the internet about other's dealings with him, I will leave it at that.

If I come up with any cure for this issue I will update the thread but for now the issue is still there and annoying as heck.

I warn others to be wise not only the way a replacement speaker cloth's "looks" but it's acoustical properties as well before replacing a usable original.

T

[codefox1]

If it's a smaller patch, you could disassemble, and poke the cloth with a coarse needle whilst watching a dull TV program for an hour. Hey, the old sets never intended to do Hip-Hop without flatulence.

[bastardbus]

That's an idea.....

I had pondered drilling a couple vent ports in the side of the thick cardboard gasket around the speaker but hate destroying an original part that survived all these years to patch an issue on a repop part.

I found placing a sheet of typing paper over a playing speaker gave the same symptoms, though a bit more exaggerated.

[mikethedruid]

You could try removing the offending grill cloth, and replace it with something like a piece of cheesecloth temporarily. Put it all back, and see if the problem goes away. If it does, then the problem was most likely the cloth. If not, then you know it is really something else... if it is the cloth, find something that looks close, but has a weave that is more open. Another thought I have had is that just MAYBE there is a sizing in the material that is clogging it. You might try washing it in warm water, letting it dry, and seeing if it is still as impermeable to air.

[Nathan Slingerland]

mikethedruid - Wouldn't washing the cloth tighten the weave? Or you're saying there's something temporarily added to the cloth for some reason ('sizing')?