I may be over thinking this but....
I have a pair of 3 way speakers from the early 1970's. They are not a common brand - the maker is WEB. I owned them for 15 years or so. I think they are a good sounding speaker and the enclosures are very nicel.
They were out of my possession for about 2 years but recently re-acquired. Unfortunatly the 6" midrange drivers now have damaged voice coils. There is rub and I suspect the voice coils have a break. The tinsel wires are fine.
All of the drivers within the speaker system are CTS - 12" woofer, phenolic ring tweeter . The 6" midrange I am dealing with is acturally catagorized by CTS as a woofer. They publish it's frequency response as 40 to 4,000 and power handling of 10 watts. These 6" drivers are wired in the enclosure as a full range so I can appreciate them as vulnerable to being overdriven which I am pretty sure is what happened to them.
I am considering replacement with some 6" Radio Shack woofers. Specs are not identical but would that matter in a ported enclosure with a 12" woofer and a tweeter? Crossover components are two capacitors - one for the woofer and one for the tweeter.
The Radio Shack woofers I am considering have a frequency response of 50 to 6,000 and power handing of 20 watts
I have a pair of 3 way speakers from the early 1970's. They are not a common brand - the maker is WEB. I owned them for 15 years or so. I think they are a good sounding speaker and the enclosures are very nicel.
They were out of my possession for about 2 years but recently re-acquired. Unfortunatly the 6" midrange drivers now have damaged voice coils. There is rub and I suspect the voice coils have a break. The tinsel wires are fine.
All of the drivers within the speaker system are CTS - 12" woofer, phenolic ring tweeter . The 6" midrange I am dealing with is acturally catagorized by CTS as a woofer. They publish it's frequency response as 40 to 4,000 and power handling of 10 watts. These 6" drivers are wired in the enclosure as a full range so I can appreciate them as vulnerable to being overdriven which I am pretty sure is what happened to them.
I am considering replacement with some 6" Radio Shack woofers. Specs are not identical but would that matter in a ported enclosure with a 12" woofer and a tweeter? Crossover components are two capacitors - one for the woofer and one for the tweeter.
The Radio Shack woofers I am considering have a frequency response of 50 to 6,000 and power handing of 20 watts
Look at Parts Express / Dayton as well.
Panasonic had great speaker drivers, mostly as OEM.
Or you could simply get the ones you have repaired, with new cones and coils, there are shops here offering same day (4 hours) service, provided they have the cones and coils in stock.
No ties to any names here.
Panasonic had great speaker drivers, mostly as OEM.
Or you could simply get the ones you have repaired, with new cones and coils, there are shops here offering same day (4 hours) service, provided they have the cones and coils in stock.
No ties to any names here.
Is it AlNiCo or ceramic motor like RS? If the former, the RS won't have as 'sweet' a sound and may not be as efficient, requiring some EQ to blend in, but otherwise OK to use.
How's the capacitor feeding the component? I mean which value?
Probably under 10 μF, which don't go well with the type of midwoofer I was thinking of. Indeed the midrange dedicated speakers that Scan Speak and SBacoustics produce. Probably also the little PA midranges . Faital Pro etc. The woofer should be low-passed, though...
So the initial idea to replace with common full range speakers ( the ones that equipped boom boxes and little stereos) might be good.
Probably under 10 μF, which don't go well with the type of midwoofer I was thinking of. Indeed the midrange dedicated speakers that Scan Speak and SBacoustics produce. Probably also the little PA midranges . Faital Pro etc. The woofer should be low-passed, though...
So the initial idea to replace with common full range speakers ( the ones that equipped boom boxes and little stereos) might be good.
That is encouraging. The magnets on both are 10oz ferrite.
@picowallspeaker : I will be removing the 12" woofers from each cabinet to access the capacitors. The two in each box are a film type if remember correctly because I did not change them 15 years ago thinking that film capacitors in a speaker crossover do not degenerate. I will remove them to test and quite likely replace them with modern ones.
It was suggested elsewhere that I install a 100V 40uF capacitor inline with the 6' midrange. It was explained that doing so would prevent frequencies below 500hZ from reaching it. I appreciate the logic in that, since it is being fed a full range signal and has twice suffered voice coil damage. I am unsure if that would be sonicaly beneficial even though it might be practical as in protecting the voice coil.
But I wonder why a 6" speaker rated at 10 watts and acting as a midrange is getting the full brunt of an amplifier's output? The speaker system itself is rated for 60 watts. Perhaps those who built the speakers thought that arrangement achieved the best sound? If any driver within a 3 way system was wired as a full range, I would have expected that to be, in this case, the 12" woofer.
I'd suggest something like a Dayton PA 130 for the midrange. Maybe overkill, but there shouldn't be any thermal problems ( in the VC).
Then a view on the tweeter and the woofer...
Wired in parallel, so higher current? Regardless, recommend inexpensive PIO motor run caps like the pioneers used for most natural speech BW. No clue without actually 'voicing' them by various age females.
Undoubtedly a superior driver to what I am dealing with but it is too small. The diameter of the hole is larger than the entire diameter of that Dayton woofer.
Earlier today I had a passport photo taken and boy, I look a lot older than the passport photo taken 10 years ago. The relationship between age and memory must have something to do with me being totally wrong about the crossover within these speakers. I was positive that there were two tubular film capacitors, encased in black with yellow end caps. Clearly, I was remembering a completely different pair of speakers.
For what it's worth, after removing a woofer and the stuffing, the photo is what I found. And I drew a schematic of how it's wired to the drivers.
The only thing that came to mind is that the components we see are the residual ones of a bigger crossover.
Those are the components of the passband filter!
Those are the components of the passband filter!
If the componets within these speakers constitute a band pass filter then that is what it has for a crossover.
Presumably then, that inductor, inline with the woofer, does something to mitigate high frequencies?
Presumably then, that inductor, inline with the woofer, does something to mitigate high frequencies?
No, wait, I said that those are the residual components...maybe! If you wire them as a passband filter 1st order for the midrange, that doesn't hurt. But then you're entering the field of acoustics and you ask yourself: what is it for?
So you don't want the woofer and the midrange to play overlapped. I see the actual speaker as an example of old type of loudspeaker, where the midrange is indeed a squeaker (sic) and is only used for refinement of the mid-hi frequencies where the woofer can't hold (pressure) because of the weight of the membrane and its directivity factor.
The squeaker introduces some articulation like some say.
But using a lowpass filter for the woofer introduces to a loss in efficiency of the woofer itself, and the particular midrange that is lost and of unknown efficiency, sensitivity, DF etc. but it is said to be 10 W, they all contribute to the the overall balance in sound.
SO the possible ways to obtain a decent sounding speaker are: put back some midranges, you'll find lots of components of that size, JVC sony Akay et all produced many low cost boxes for their mini systems that incorporated a decent full range. Not sure that you want to hear or see the moving mass hitting the bottom or go over excursion, as intermodulated distortion happens and it's bad!
Or, get a Faital pro / Dayton / whatever driver with Fs around 100 Hz ( a dedicated midrange, that is) but still the lower octaves need to be eliminated. So a 40 uF cap becomes more acceptable in this view. But 'hitting the bottom or go over excursion' means that full power is applied so the VC is going to have thermal problems, and you want to have a reliable speaker that doesn't break at the first loud musical passage.
The tweeter has ferrofluid...
So you don't want the woofer and the midrange to play overlapped. I see the actual speaker as an example of old type of loudspeaker, where the midrange is indeed a squeaker (sic) and is only used for refinement of the mid-hi frequencies where the woofer can't hold (pressure) because of the weight of the membrane and its directivity factor.
The squeaker introduces some articulation like some say.
But using a lowpass filter for the woofer introduces to a loss in efficiency of the woofer itself, and the particular midrange that is lost and of unknown efficiency, sensitivity, DF etc. but it is said to be 10 W, they all contribute to the the overall balance in sound.
SO the possible ways to obtain a decent sounding speaker are: put back some midranges, you'll find lots of components of that size, JVC sony Akay et all produced many low cost boxes for their mini systems that incorporated a decent full range. Not sure that you want to hear or see the moving mass hitting the bottom or go over excursion, as intermodulated distortion happens and it's bad!
Or, get a Faital pro / Dayton / whatever driver with Fs around 100 Hz ( a dedicated midrange, that is) but still the lower octaves need to be eliminated. So a 40 uF cap becomes more acceptable in this view. But 'hitting the bottom or go over excursion' means that full power is applied so the VC is going to have thermal problems, and you want to have a reliable speaker that doesn't break at the first loud musical passage.
The tweeter has ferrofluid...
@picowallspeaker - Thank you for the input.
I cannot say whether or not I will take on the search for a dedicated midrange driver as you suggested. So far, that free air resonance figure of 100 has eluded me. Using that at as a search term for 6 1/2" midranges led me to car audio products. Looking at Faital products, I did not see that specification published.
I must consider expendatures being retired and on a fixed income. If I stick to somethng mundane like the Radio Shack 40-1011A's that I mentioned earlier, are you agreeing with the non-DIY Audio source that installing a 40uF capacitor would prevent low frequencies from reachng the midrange? That "source" specified frquencies below 500hZ would not reach the midrange.
What would I use to bring that figure down to 300hZ or 250hZ?
I drew in red what I think would be the correct placement of that 40uF capacitor.
I cannot say whether or not I will take on the search for a dedicated midrange driver as you suggested. So far, that free air resonance figure of 100 has eluded me. Using that at as a search term for 6 1/2" midranges led me to car audio products. Looking at Faital products, I did not see that specification published.
I must consider expendatures being retired and on a fixed income. If I stick to somethng mundane like the Radio Shack 40-1011A's that I mentioned earlier, are you agreeing with the non-DIY Audio source that installing a 40uF capacitor would prevent low frequencies from reachng the midrange? That "source" specified frquencies below 500hZ would not reach the midrange.
What would I use to bring that figure down to 300hZ or 250hZ?
I drew in red what I think would be the correct placement of that 40uF capacitor.
The placement of the cap looks correct. Using a text book 1st order high pass, you'll want around 90 or 110uf to get down to 300 or 250hz, respectively.
Being the curious man that I am, I googled Web Speakers because I had never heard of them. And I came across a post on AK where you posted some pics of your Web Speakers. Are the speakers this thread is about, the Major I's? If so, it appears they used open backed mids with no sub enclosure. You may want to consider adding a small enclosure behind the mid so it's not subjected to the forces of 12".
Being the curious man that I am, I googled Web Speakers because I had never heard of them. And I came across a post on AK where you posted some pics of your Web Speakers. Are the speakers this thread is about, the Major I's? If so, it appears they used open backed mids with no sub enclosure. You may want to consider adding a small enclosure behind the mid so it's not subjected to the forces of 12".
Thank you for those numbers and the suggestion if isolating the midrange. I'll need to give some thought on how to do that.
Yes, these are those Major I's from that AK thread.
I used to have access to a nicely equipped woodshop but that luxury is gone. I may be able to cobble something together at a friends place who has a radial arm saw. I don't visit frequently as it's an hour's drive each way. I will see what I can come up with for materials to accomplish it.
It would be a box which must fit through the woofer cutout. Then be glued and screwed onto the inside of the front baffle.
I abandoned the notion of constructing a wooden midrange enclosure and took to looking around for alternatives. The other day, I slowly walked the aisles of the local Dollar Store and spotted some shallow plastic plant pots. I took two of them home to check for size and they seem to be a perfect fit. They are exactly the same 6" per side as is the 6" diameter of the midrange cutout and deep enough to allow clearance for the magnet. Or more precisely, clearance for the magnre of the Realistic 6 1/2" woofers.
I have some LePages gel glue called Extreme Glue that, according to the packaging, will glue nearly anything to just about anything else. Plastic and wood are cited as bondable materials.
I concocted a method to apply pressure to the join so the glue can cure for 24 hours. Tomorrow will tell the tale of whether of not the glueing was successful.
I have some LePages gel glue called Extreme Glue that, according to the packaging, will glue nearly anything to just about anything else. Plastic and wood are cited as bondable materials.
I concocted a method to apply pressure to the join so the glue can cure for 24 hours. Tomorrow will tell the tale of whether of not the glueing was successful.
I took a break to consider options.
Something I did do was compare one cabinet in which I "loose laid" one of the Radio Shack woofers I have into the midtange hole. That cabinet has the insolation enclosure installed as depicted above. I also installed a 100uF capacitor in line to block low frequencies which I believe will be in the 250hZ - 300hZ and lower area.
The other cabinet has the original, functioning 6 1/2" CTS woofer as it's midrange. No isolation enclosure and no in line capacitor. The same state as when the speaker system was made.
Listening to both of them side by side with CD source and pre-amp in mono, the original, unaltered speaker enclosure sounds better to me.
My perception of the speaker with the Radio Shack woofer in place and the 100uF in line capacitor is it is "squawkier".
Not as pleasant or smooth as the cabinet in it's original state with the original 10 watt CTS 6 1/2" woofer as it's midrange. I thought that perhaps this was because the Radio Shack woofer has a wider frequency response. It rolls off at 6,000hZ whereas the CTS woofer rolls off at 4,000hZ. Sensitivity of both is 89dB so they should both be equally loud.
I decided to bite the bullet and obtain new drivers to use as midranges and got overwhelmed by the choices. Since Parts Express has an extensive assortment, I corresponded with them and chose Dayton Audio DC160-8. A part they denote as "classic woofer". They are on order and I should have them in my possetion this upcoming week.
They have a similar frequency response to the CTS, have rubber surrounds and paper cones like the CTS but they have a lower sensitivity of 86dB compared to the 89dB of the CTS.. So 3dB less. My hope is that this diference will be barely detectible.
I was surprised to be provided with additional specs for that particular CTS driver and compared them to those of the Dayton:
CTS fs 40 Dayton fs 35.7
CTS qts 0.29 Dayton qts 0.34
CTS vas 35 (units unknown) Dayton vas 17.9 liters
CTS frequncy response 40hZ to 4,000hZ Dayton frequecy reaponse 30hZ to 4,000hZ.
Since the CTS 6 1/2" is rated for 10 watts and the Dayton 6 1/2" is rated for 50 watts and has a larger voice coil, it is also my hope that I can dispense with that 100uF in line capacitor and run the Daytons full range as was with the CTS.
One possible wrinkle is depth as it is going to be close with that midrange isolation chamber in place.
My listening habits are conservative and I am not concerned about overdriving them. I would not and never did overdrive them even with the 10 watt CTS midranges in place with them wired as a full range. It was the clown that I bought them back from (or his son) who cooked them.
FWIW, the picture below is the interior of the speaker enclosure. It shows the vertical PVC pipe entering a bottom chamber which then in turn vents into the room.
Something I did do was compare one cabinet in which I "loose laid" one of the Radio Shack woofers I have into the midtange hole. That cabinet has the insolation enclosure installed as depicted above. I also installed a 100uF capacitor in line to block low frequencies which I believe will be in the 250hZ - 300hZ and lower area.
The other cabinet has the original, functioning 6 1/2" CTS woofer as it's midrange. No isolation enclosure and no in line capacitor. The same state as when the speaker system was made.
Listening to both of them side by side with CD source and pre-amp in mono, the original, unaltered speaker enclosure sounds better to me.
My perception of the speaker with the Radio Shack woofer in place and the 100uF in line capacitor is it is "squawkier".
Not as pleasant or smooth as the cabinet in it's original state with the original 10 watt CTS 6 1/2" woofer as it's midrange. I thought that perhaps this was because the Radio Shack woofer has a wider frequency response. It rolls off at 6,000hZ whereas the CTS woofer rolls off at 4,000hZ. Sensitivity of both is 89dB so they should both be equally loud.
I decided to bite the bullet and obtain new drivers to use as midranges and got overwhelmed by the choices. Since Parts Express has an extensive assortment, I corresponded with them and chose Dayton Audio DC160-8. A part they denote as "classic woofer". They are on order and I should have them in my possetion this upcoming week.
They have a similar frequency response to the CTS, have rubber surrounds and paper cones like the CTS but they have a lower sensitivity of 86dB compared to the 89dB of the CTS.. So 3dB less. My hope is that this diference will be barely detectible.
I was surprised to be provided with additional specs for that particular CTS driver and compared them to those of the Dayton:
CTS fs 40 Dayton fs 35.7
CTS qts 0.29 Dayton qts 0.34
CTS vas 35 (units unknown) Dayton vas 17.9 liters
CTS frequncy response 40hZ to 4,000hZ Dayton frequecy reaponse 30hZ to 4,000hZ.
Since the CTS 6 1/2" is rated for 10 watts and the Dayton 6 1/2" is rated for 50 watts and has a larger voice coil, it is also my hope that I can dispense with that 100uF in line capacitor and run the Daytons full range as was with the CTS.
One possible wrinkle is depth as it is going to be close with that midrange isolation chamber in place.
My listening habits are conservative and I am not concerned about overdriving them. I would not and never did overdrive them even with the 10 watt CTS midranges in place with them wired as a full range. It was the clown that I bought them back from (or his son) who cooked them.
FWIW, the picture below is the interior of the speaker enclosure. It shows the vertical PVC pipe entering a bottom chamber which then in turn vents into the room.
I wrote Pa 130, not Dc 160 ! I dunno where you're experiments are leading to, but, as I wrote before, with two elemnts in the crossover and you are going to make a 3 way speaker with parallel crossover connection, the 2 that you have available, a 6.8 uF cap and about 0.5 mH inductor, you can only filter the mid. Which you didn't.
And, since you report the data of the speakers, I remind you that the 100 Hz resonant frequency target was easely detectable in the Dayton Pa 130 data ( about 90 Hz Fs ) as in the Dayton DC 160 ( half the Fs !)
The diameter data could be have been ditched, since you were to renew the cabinet there was some way to adapt it .
Sincerely, you should get rid of that piece of junk in the back and make a way for each couple of wires to the back, or front, or wherever, in order to start on experimenting without impediments
And, since you report the data of the speakers, I remind you that the 100 Hz resonant frequency target was easely detectable in the Dayton Pa 130 data ( about 90 Hz Fs ) as in the Dayton DC 160 ( half the Fs !)
The diameter data could be have been ditched, since you were to renew the cabinet there was some way to adapt it .
Sincerely, you should get rid of that piece of junk in the back and make a way for each couple of wires to the back, or front, or wherever, in order to start on experimenting without impediments
I dismissed that PA130 simply because of it's size. Presubably some type of adaptor ring could have been created but I do not have the tools or facility to do that. My objective was more a restoration rather than a modification.
The Dayton DC160 woofers I ordered arrived last week and I had the opportuinity to "experiment" with them today. I was able to compare the one cabinet with the Dayton woofer and it's newly insatlled isolation chamber in place with the other cabinet which is as it left the factory with it's 6 1/2" CTS driver and completely open interior
My feeling here was that the factory stock cabinet sounded better..
I allowed myself the ability to hear the new Dayton driver in it's isolation chamber with and without the 100uF inline capacitor.
My second finding was that I preferred how the speaker with the isolation chamber sounded without the 100uF capacitor in place. In other words, wired as a full range.
The 100uF capacitor will be elimated.
Next I removed the original CTS 6 1/2" driver from the stock cabinet and fitted the new Dayton 6 1/2". This cabinet has no isolation chamber so the Dayton driver shares the internal space with the 12" woofer. And again, being driven as a full range
My impression here is I prefer how that cabinet sounds over the other which has the isolation chamber. I will remove that on isolation chamber that I installed.
My preference likely contradicts everything connected to loudspeaker construction. Perhaps others would hear things differently than I do or can critically listen better but for my own satisfaction, I will leave the boxes as is. So all I am going to do is swap out those 10 watt CTS 6 1/2" woofers and install the 50 watt 6 1/2" Dayton woofers and call it a day.
The Dayton DC160 woofers I ordered arrived last week and I had the opportuinity to "experiment" with them today. I was able to compare the one cabinet with the Dayton woofer and it's newly insatlled isolation chamber in place with the other cabinet which is as it left the factory with it's 6 1/2" CTS driver and completely open interior
My feeling here was that the factory stock cabinet sounded better..
I allowed myself the ability to hear the new Dayton driver in it's isolation chamber with and without the 100uF inline capacitor.
My second finding was that I preferred how the speaker with the isolation chamber sounded without the 100uF capacitor in place. In other words, wired as a full range.
The 100uF capacitor will be elimated.
Next I removed the original CTS 6 1/2" driver from the stock cabinet and fitted the new Dayton 6 1/2". This cabinet has no isolation chamber so the Dayton driver shares the internal space with the 12" woofer. And again, being driven as a full range
My impression here is I prefer how that cabinet sounds over the other which has the isolation chamber. I will remove that on isolation chamber that I installed.
My preference likely contradicts everything connected to loudspeaker construction. Perhaps others would hear things differently than I do or can critically listen better but for my own satisfaction, I will leave the boxes as is. So all I am going to do is swap out those 10 watt CTS 6 1/2" woofers and install the 50 watt 6 1/2" Dayton woofers and call it a day.
