okay
I've uploaded a few pics for the sake of my project and the greater good
Dropbox - Lenten S4 - Simplify your life
I've uploaded a few pics for the sake of my project and the greater good
Dropbox - Lenten S4 - Simplify your life
Your photos are now preserved in a directory called "stubbs04" somewhere near Seattle!
I've managed to work out the woofer section of the crossover but I'm missing some parts values. It is the same as the woofer section of that Tabor crossover with different parts. The tweeter section is different but I don't think it matters because the tweeter is staying.
What does it say on the white thing between the yellow cap marked 3.3uF and the yellow wrapped coil?
You probably should measure the cutout for the woofer and compare it to the Seas unit.
I've managed to work out the woofer section of the crossover but I'm missing some parts values. It is the same as the woofer section of that Tabor crossover with different parts. The tweeter section is different but I don't think it matters because the tweeter is staying.
What does it say on the white thing between the yellow cap marked 3.3uF and the yellow wrapped coil?
You probably should measure the cutout for the woofer and compare it to the Seas unit.
You'll find there is a papaerclip symbol in the reply box which allows you to upload images to a post. The baffle and the filter images are the useful ones now. It's polite to shrink them to 640x480 jpg or png format and then everyone can see them.
I misread the Tabor filter.
That LCR is 2mH/3.3R/8uF and I'll run a sim.
The drivers are Audax HD20B25H Bass and HD 12x9 D25 tweeter.
I have the PDF for the bass, and the tweeter is still available at Falcon AFAIK, so a PDF available I think. I have the PDF for the SEAS P21/RE.
Good progress here. I can't quite figure out the bass filter beyond a 3.3uF cap, 2 coils and 2 resistors, but the tweeter looks like 4th order with 4.7uF and 6.8uF. Sort of thing I build. These sort of things are often negative polarity on tweeter.
We could do with the resistor values here. You need measuring equipment for coils, so we must wing it there.
I misread the Tabor filter.
That LCR is 2mH/3.3R/8uF and I'll run a sim.
The drivers are Audax HD20B25H Bass and HD 12x9 D25 tweeter.
I have the PDF for the bass, and the tweeter is still available at Falcon AFAIK, so a PDF available I think. I have the PDF for the SEAS P21/RE.
Good progress here. I can't quite figure out the bass filter beyond a 3.3uF cap, 2 coils and 2 resistors, but the tweeter looks like 4th order with 4.7uF and 6.8uF. Sort of thing I build. These sort of things are often negative polarity on tweeter.
We could do with the resistor values here. You need measuring equipment for coils, so we must wing it there.
It's hard to make out from the photos but this is what I've got.
Obviously we have no idea what the inductors are but....
I'm quite sure the woofer branch is correct. Just missing the cap value.
The tweeter branch is problematic. Aren't the caps reversed? I couldn't make out what happens after that with the white thing and the red wrapped coil but it ends up connecting the 12X9 reversed phased. The red wire which is soldered to ground on the board going to the red terminal on the 12X9. It also seems that the input resistor on the input to the tweeter section is pretty large. It's almost double the value in the Tabor.
A picture of the bottom of the board would be superb and values for the white caps or whatever they are.
Obviously we have no idea what the inductors are but....
I'm quite sure the woofer branch is correct. Just missing the cap value.
The tweeter branch is problematic. Aren't the caps reversed? I couldn't make out what happens after that with the white thing and the red wrapped coil but it ends up connecting the 12X9 reversed phased. The red wire which is soldered to ground on the board going to the red terminal on the 12X9. It also seems that the input resistor on the input to the tweeter section is pretty large. It's almost double the value in the Tabor.
A picture of the bottom of the board would be superb and values for the white caps or whatever they are.
I was rereading the Tabor article and noticed it said that the surrounds on the HD20B25's were PVC which explains why they warp out. The KEF B200 SP1039 as used in the 104aB has the same problem. The PVC is better acoustically than Neoprene but eventually loses it's shape.
I also thought the graphs for the Tabor might be useful to Steve.
I also thought the graphs for the Tabor might be useful to Steve.
Attachments
Hmm, that woofer looks a stinker to equalize, but the LCR must be doing it! Usual negative polarity 3.5kHz crossover. Lined the phase up with a woofer that is recessed about 5cm on acoustic centre. Half a wavelength, you see.
I have to switch to Windows 7 to run a sim, which is a pain. But we'll see.
You are right about the old PVC surrounds. They sagged like crazy. I had to turn the woofer every month just to stop the voicecoil rubbing on these:
I have to switch to Windows 7 to run a sim, which is a pain. But we'll see.
You are right about the old PVC surrounds. They sagged like crazy. I had to turn the woofer every month just to stop the voicecoil rubbing on these:
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Two of the "white things" are resistors but we can't see the sides of the other two.
More pictures = good.
It is a pretty "stinky" curve but the end result was really wonderful. As I said before, the poor man's BC1.
The KEF 104aB people are in big trouble although Falcon is prototyping a new B200 as we speak. My Calinda's have neoprene surrounds.
That back mount rebate on the S4's might make fitting a replacement difficult.
More pictures = good.
It is a pretty "stinky" curve but the end result was really wonderful. As I said before, the poor man's BC1.
The KEF 104aB people are in big trouble although Falcon is prototyping a new B200 as we speak. My Calinda's have neoprene surrounds.
That back mount rebate on the S4's might make fitting a replacement difficult.
Pics
Hi Guys
Ive taken a few pics and Ive written down what is on the white and yellow blocks with a rough diagram (see the pic called "descriptions". also you will see the pic of the back of the board.
Hope this makes sense.
Sorry I didnt manage to attach to the message so its back onto the Drop Box:
Dropbox - Lenten S4 - Simplify your life
Hi Guys
Ive taken a few pics and Ive written down what is on the white and yellow blocks with a rough diagram (see the pic called "descriptions". also you will see the pic of the back of the board.
Hope this makes sense.
Sorry I didnt manage to attach to the message so its back onto the Drop Box:
Dropbox - Lenten S4 - Simplify your life
Thanks for the pics.
Here's the new and improved drawing. It's a little crooked but hey, I was using a Guiness coaster as a straight edge.
Steve is probably more organized (and experienced) with Sim programs so he'll probably get to this before I do.
Hopefully, it will just take a bit of tweeking to make this crossover work with some other woofer.
Chris
Here's the new and improved drawing. It's a little crooked but hey, I was using a Guiness coaster as a straight edge.
Steve is probably more organized (and experienced) with Sim programs so he'll probably get to this before I do.
Hopefully, it will just take a bit of tweeking to make this crossover work with some other woofer.
Chris
Attachments
That's a good and useful schematic, Chris. I'd usually mirror image the backview in Windows Paint to figure it out, but trust you on that.
I'll sim it and the variations now with Visaton Boxsim. I might use the Visaton W170S-8 to see how it behaves electrically, since we seem to be looking at 25 ohms at 10kHz for these drivers.
It's quite like the Spendor BC1 bass circuit, isn't it?
Spendor BC1
Saw the new Tom Hanks "Fred Rogers" film tonight. This is the original Esquire article that inspired the film: Can You Say...Hero? - Mr. Rogers Profile Interview
Very good. Wasn't he "Sleepless in Seattle"?
I'll sim it and the variations now with Visaton Boxsim. I might use the Visaton W170S-8 to see how it behaves electrically, since we seem to be looking at 25 ohms at 10kHz for these drivers.
It's quite like the Spendor BC1 bass circuit, isn't it?
Spendor BC1
Saw the new Tom Hanks "Fred Rogers" film tonight. This is the original Esquire article that inspired the film: Can You Say...Hero? - Mr. Rogers Profile Interview
Very good. Wasn't he "Sleepless in Seattle"?
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I normally use my Mac Pro so I used the Preview "horizontal flip" function on the topside photo and put it next to the solder side photo. It should be good, I did it twice. Naturally all my speaker software is for Windows. Barf.
You're right it is like a BC1. Nothing like stealing from the best.
I should probably try to find some BC1's and buy them.
I used to live a few blocks away from the Space Needle. When I retired, I moved across the water to the West. Very bucolic. Now I'm a country squire.
You're right it is like a BC1. Nothing like stealing from the best.
I should probably try to find some BC1's and buy them.
I used to live a few blocks away from the Space Needle. When I retired, I moved across the water to the West. Very bucolic. Now I'm a country squire.
I made a mistake on the bass shunt of the Lentek S4 circuit with 33R instead of 47R, but the result applies:
This is the Tabor after filtering:
Below are some simulations. The Tabor is a very driver specific circuit. 1.3kHz deep notch as expected. Works best with a similar W170S driver as I also expected. Not much bafflestep.
The Lentek S4 is not driver specific at all. Lots of bafflestep. The bass shunt resistor, which I mistakenly put in 33R for does a lot to control the Q of the circuit. It also heavily influences impedance and must run very hot.
I'm tired now, so I'll shut up there.
This is the Tabor after filtering:
Below are some simulations. The Tabor is a very driver specific circuit. 1.3kHz deep notch as expected. Works best with a similar W170S driver as I also expected. Not much bafflestep.
The Lentek S4 is not driver specific at all. Lots of bafflestep. The bass shunt resistor, which I mistakenly put in 33R for does a lot to control the Q of the circuit. It also heavily influences impedance and must run very hot.
I'm tired now, so I'll shut up there.
Attachments
I've got a pretty good feel for this project now. It's worth knowing where you get the bits if anything needs adjusment:
Impact Audio - Visaton Loudspeakers, TEAC, Myryad & Roksan HiFi Sy
Falcon Acoustics | The Leading DIY Speaker Parts and Kit Supplier since 1972
Blue Aran - The UK's no.1 Loudspeaker Component Stockist
Speaker Repair, Speaker Kits, Loudspeaker Repair, Kits and Drive Units, Subwoofer Amplifier Kit
Hardware from most builders merchants, like 40W soldering irons and lead-free solder:
Draper Expert SI40A 40W Soldering Iron (230V) - Machine Mart - Machine Mart
https://www.machinemart.co.uk/p/blue-spot-lead-free-solder-100g1mm/
You always tin an iron the first time it warms up, and before the tip oxidises and is then totally useless!
I notice my old favourite and simple circuits work just as well as most other stuff:
Impact Audio - Visaton Loudspeakers, TEAC, Myryad & Roksan HiFi Sy
Falcon Acoustics | The Leading DIY Speaker Parts and Kit Supplier since 1972
Blue Aran - The UK's no.1 Loudspeaker Component Stockist
Speaker Repair, Speaker Kits, Loudspeaker Repair, Kits and Drive Units, Subwoofer Amplifier Kit
Hardware from most builders merchants, like 40W soldering irons and lead-free solder:
Draper Expert SI40A 40W Soldering Iron (230V) - Machine Mart - Machine Mart
https://www.machinemart.co.uk/p/blue-spot-lead-free-solder-100g1mm/
You always tin an iron the first time it warms up, and before the tip oxidises and is then totally useless!
I notice my old favourite and simple circuits work just as well as most other stuff:
I've been pawing through driver data sheets and I think the one we want is the Seas P21RE/P which is available from Falcon for £41.83 VAT included. It doesn't cost too much, it should be able to fit without too much bother and the specs suit the existing enclosure.
A lot of the "modern" drivers have a lower Vas and the speakers from the 80's were higher with lower Fs. I guesstimated the volume of the S4 box to be just under 28 liters which would be close to correct. This would be a F3 in the mid-60s and a Q of around 1.
The Seas doesn't have the weird double bump on the high end but it shouldn't be too difficult to adjust the S4 woofer section to suit. It is more efficient so the input resistor on the tweeter section would need to be smaller.
We don't know 2 things:
1) the values of the coils - can't do much about this
2) the actual volume of the enclosure - stubbs04 can measure the outside and measure the panel thickness (looks like about 12mm in photo).
If it just requires a few caps and resistors to adjust the crossover then the main cost will be the woofers. I don't know what the budget for this might be, I don't know how attached stubbs04 is to the S4's and I don't know if there are any nice used speakers available in or around Edinburgh. The problem with trying to find some more used Audax woofers is their surrounds are probably going bad as well.
Thoughts?
A lot of the "modern" drivers have a lower Vas and the speakers from the 80's were higher with lower Fs. I guesstimated the volume of the S4 box to be just under 28 liters which would be close to correct. This would be a F3 in the mid-60s and a Q of around 1.
The Seas doesn't have the weird double bump on the high end but it shouldn't be too difficult to adjust the S4 woofer section to suit. It is more efficient so the input resistor on the tweeter section would need to be smaller.
We don't know 2 things:
1) the values of the coils - can't do much about this
2) the actual volume of the enclosure - stubbs04 can measure the outside and measure the panel thickness (looks like about 12mm in photo).
If it just requires a few caps and resistors to adjust the crossover then the main cost will be the woofers. I don't know what the budget for this might be, I don't know how attached stubbs04 is to the S4's and I don't know if there are any nice used speakers available in or around Edinburgh. The problem with trying to find some more used Audax woofers is their surrounds are probably going bad as well.
Thoughts?
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