I've got a pair of Automatic Radio bookshelf speakers that I recently modded with a Foster tweeter from a pair of Zenith Allegro speakers.
The problem is the doped cloth surrounds. The dope has hardened and nothing I have tried within reason will remove it and only softens the dope up for a few months.
The box before swapping tweeters. This is a photo of the 4 ohm version, but the ones I modded were the 8 ohm version. Same cabinet same size drivers just different ohms.
If it is not possible to remove the dope without destroying the speaker I will need an 8 ohm speaker that is exactly 5" in diameter with a bolt circle diameter of 4 3/4" that can handle at least 20 watts and can be rear mounted on a baffle. So far in a casual search, most 5" speakers I've found are larger than 5" or have a bolt circle diameter of greater than 4 3/4". Response should be from about 70Hz to around 3.5kHz. I can get a more exact number tomorrow.
What sort of reasonably priced speakers under $50 are available?
I am looking at a set of Klipsch speakers, however I most likely will not be able to get those until later this year or possibly next year and need something in the mean time.
The problem is the doped cloth surrounds. The dope has hardened and nothing I have tried within reason will remove it and only softens the dope up for a few months.
The box before swapping tweeters. This is a photo of the 4 ohm version, but the ones I modded were the 8 ohm version. Same cabinet same size drivers just different ohms.
If it is not possible to remove the dope without destroying the speaker I will need an 8 ohm speaker that is exactly 5" in diameter with a bolt circle diameter of 4 3/4" that can handle at least 20 watts and can be rear mounted on a baffle. So far in a casual search, most 5" speakers I've found are larger than 5" or have a bolt circle diameter of greater than 4 3/4". Response should be from about 70Hz to around 3.5kHz. I can get a more exact number tomorrow.
What sort of reasonably priced speakers under $50 are available?
I am looking at a set of Klipsch speakers, however I most likely will not be able to get those until later this year or possibly next year and need something in the mean time.
You can try to remove doping.
If successful (you have a reasonable chance to) you can later apply a better one, which stays flexible.
Some people (I have even seen it recommended here 🙄) use diluted carpenter's glue , contact cement, "liquid electrical tape", etc. which look good at the beginning but all harden, sooner or later.
I suggest soaking surround, but only the curved area which allows movement, not where it is glued to frame or cone, letting solvent soften it and removing whatever you can with a dry piece of cotton cloth.
Not paper or a cotton ball which will leave fibers behind.
Re-soak and repeat.
Bit by bit you will remove most of it and resonant frequency should lower to some usable value, even when dry.
Maybe you don't even need to re-dope surround, whatever remains (you'll never pull 100%) is enough to seal it but if necessary, use poor-man's dope: tile roof sealant, a water based white liquid "latex" (the paint shop guy will know what you are talking about), which dries first with a bluish hue and then transparent and never fully dries, it stays sticky forever .
Plan B: let solvent dissolve adhesive , fully remove surround and glue in place a new one.
Typically foam.
Solvents: best is acetone but you can try car paint type thinner or Toluene or ethyl ether.
If successful (you have a reasonable chance to) you can later apply a better one, which stays flexible.
Some people (I have even seen it recommended here 🙄) use diluted carpenter's glue , contact cement, "liquid electrical tape", etc. which look good at the beginning but all harden, sooner or later.
I suggest soaking surround, but only the curved area which allows movement, not where it is glued to frame or cone, letting solvent soften it and removing whatever you can with a dry piece of cotton cloth.
Not paper or a cotton ball which will leave fibers behind.
Re-soak and repeat.
Bit by bit you will remove most of it and resonant frequency should lower to some usable value, even when dry.
Maybe you don't even need to re-dope surround, whatever remains (you'll never pull 100%) is enough to seal it but if necessary, use poor-man's dope: tile roof sealant, a water based white liquid "latex" (the paint shop guy will know what you are talking about), which dries first with a bluish hue and then transparent and never fully dries, it stays sticky forever .
Plan B: let solvent dissolve adhesive , fully remove surround and glue in place a new one.
Typically foam.
Solvents: best is acetone but you can try car paint type thinner or Toluene or ethyl ether.
If it is oil based.
Then castor oil or brake fluid dot 3 or 4
will soften it / help remove.
Otherwise could use a mini cutoff disk on a Dremel tool.
To cutoff the studs.
Mount new speakers and new bolt pattern with short woodscrews.
Otherwise found a high sensitivity 5" from Visaton
Which matches outer size and center to center for screw/bolt holes.
Visaton BG13P
outer is 131mm or = 5 inches
Hole mounts 120mm 0r = 4.72 inches
hole size is 4.2mm
So basically close to 3/16
so typical screw stud would go thru
Then castor oil or brake fluid dot 3 or 4
will soften it / help remove.
Otherwise could use a mini cutoff disk on a Dremel tool.
To cutoff the studs.
Mount new speakers and new bolt pattern with short woodscrews.
Otherwise found a high sensitivity 5" from Visaton
Which matches outer size and center to center for screw/bolt holes.
Visaton BG13P
outer is 131mm or = 5 inches
Hole mounts 120mm 0r = 4.72 inches
hole size is 4.2mm
So basically close to 3/16
so typical screw stud would go thru
"Different ohms" is a nonsense. The OHM is a measure unit like kilograms, metres or litres. Are different 4l of water from 4l of sand, for example? The proper way was to say "different resistance (or impedance in this case)" Both resistance and impedance are measured in Ohms but aren't Ohms itself. Ohm was a person and the resistance unit is in his honour.
Now if I were doing an open baffle with a larger woofer for the bass, that speaker would be perfect.
That said I could not fit a driver larger than 5" in there anyways.
That said I could not fit a driver larger than 5" in there anyways.
pretty much
Was trying to find something with better bass.
And there is plenty good performers in the 30 ish dollar range.
But the basket ring go to 5.4 to 5.6 inches.
So why mentioned probably just cut off the studs.
Then work out a new crossover.
Pretty straight forward since we'll have all the frequency
response data with new drivers.
Was trying to find something with better bass.
And there is plenty good performers in the 30 ish dollar range.
But the basket ring go to 5.4 to 5.6 inches.
So why mentioned probably just cut off the studs.
Then work out a new crossover.
Pretty straight forward since we'll have all the frequency
response data with new drivers.
If all the 5” units are too big, maybe step down to a 4” and add an adapter ring of some sort. I tried a Visaton W100S as a bass/mid and was pleased enough with it in that role.
The issue I have is that there's no real space to use anything larger than 5" so I'd have to go smaller and take a slight hit on bass response.
If manufacturers would list their speakers their actual size instead of making you look deep in the specs to find it or if manufacturers made a 5" speaker actually 5" like they used to be, then it would be a lot easier.
I have a pair of woofers from a pair of Olson S-850 speakers where I could cut the piece out between the mounting holes and edge of the speaker and they would fit, but one driver is pretty much shot so that was a no-go and I think those smaller Olsons weren't rated above 10 watts either.
If manufacturers would list their speakers their actual size instead of making you look deep in the specs to find it or if manufacturers made a 5" speaker actually 5" like they used to be, then it would be a lot easier.
I have a pair of woofers from a pair of Olson S-850 speakers where I could cut the piece out between the mounting holes and edge of the speaker and they would fit, but one driver is pretty much shot so that was a no-go and I think those smaller Olsons weren't rated above 10 watts either.
I did replace the 8 ohm woofers with the 4 ohm version and installed a proper 12 dB/octave crossover.
So far they sound great, however I don't really like the 20 watt rating of the woofer.
Using the DATS V3 speaker tester here's what I get for the whole speaker.
Here's the measurement of the 4 ohm woofer.
So when selecting a driver I'd need to find one that at least has a F(s) of 95Hz or lower and about the same or smaller magnet size in order to get a similar or better response, right?
So far they sound great, however I don't really like the 20 watt rating of the woofer.
Using the DATS V3 speaker tester here's what I get for the whole speaker.
Here's the measurement of the 4 ohm woofer.
So when selecting a driver I'd need to find one that at least has a F(s) of 95Hz or lower and about the same or smaller magnet size in order to get a similar or better response, right?
Looks like this driver will fit perfectly.
https://www.parts-express.com/Dayton-Audio-PA130-8-5-Full-Range-PA-Driver-295-010?quantity=1#
However it's only available in an 8 ohm version.
I do have two more of the same cabinets though.
So perhaps I could install one in the cabinets with the tweeter then one in the empty cabinets. I'd then use a 1/4" jack on each speaker so they will be wired in parallel for a 4 ohm impedance.
The benefit is the speaker with the tweeter will be at ear level given I'd stack them on top of each other.
The existing cabinet is .216 sq ft.
Would that work fine for the driver?
Here's the driver specs.
https://www.parts-express.com/pedocs/specs/295-010-dayton-audio-pa130-8-specifications-46131.pdf
EDIT:
Hmmmmmmmm might not work due to available space.
Might be a prime opportunity to find a larger cabinet so that I can use a larger woofer.
https://www.parts-express.com/Dayton-Audio-PA130-8-5-Full-Range-PA-Driver-295-010?quantity=1#
However it's only available in an 8 ohm version.
I do have two more of the same cabinets though.
So perhaps I could install one in the cabinets with the tweeter then one in the empty cabinets. I'd then use a 1/4" jack on each speaker so they will be wired in parallel for a 4 ohm impedance.
The benefit is the speaker with the tweeter will be at ear level given I'd stack them on top of each other.
The existing cabinet is .216 sq ft.
Would that work fine for the driver?
Here's the driver specs.
https://www.parts-express.com/pedocs/specs/295-010-dayton-audio-pa130-8-specifications-46131.pdf
EDIT:
Hmmmmmmmm might not work due to available space.
Might be a prime opportunity to find a larger cabinet so that I can use a larger woofer.
Last edited:
If noting works you can try this mix.
The mixing ratio is 1 part glycerol and 1-2 parts red spirit. The alcohol dilutes the glycerol and makes it easier for it to penetrate the "rubber".
Start by cleaning the rubber with soap and water to remove as much loose dirt as possible.
When the rubber has dried, brush on the mixture repeatedly but let it dry up a little in between.
Maby you can treat also from the backside.
It could take time/days and even a week,
Good luck!
I will keep that in mind for other speakers with hardened doped surrounds as I've already got these set up for the 4 ohm woofers.