SP1200, 1700, or 2500 Crossover Diagrams

Looks to be a good replacement woofer. Check the OD and ID dimension with your current cutout in the cabinet to be sure. It doesn't matter the connection on the inductor. It is not marked in or out.

Mounting Information for new woofer from website...
  • Overall Outside Diameter12.01"
  • Baffle Cutout Diameter10.98"
  • Depth4.72"

The Pioneer woofers You used, How tight did they fit in the front baffle board on yours ? The Pioneer You used shows 10.70" and the Visaton I posted the link to are 10.98", Visaton Depth is about a 1/4 shallower than the pioneer, the Overall OD is slightly smaller. I don't see any real issue, worse case I may have to open the hole slightly with a sanding drum.
 
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I had to open up the baffle a little bit using a sander to get them to drop in. But mine is a SP2500. That one used the Sansui W-113 woofer. The SP1700 used the W-110. The dimensions may be slightly different. I would just anticipate having to open the hole a little to get them in.
 
Not an expert at this, but this is the woofer I was considering for my 2500s: https://www.parts-express.com/dayton-audio-dc300-8-12-classic-woofer--295-320 Sealed, it's ideal for the 2500 cabinet.

I think what will hurt any replacement is the lower efficiency of choices.

I'm going to add a 1.5mh coil with RC (50uf !! and 7.5ohmR) and stock woofer and see what that does before I consider a replacement. The size of these cabinets is going to limit any of the low end output, but I think this approach will clean it up quite a bit with a recap on the factory crossovers.

In hindsight I wished I would have done this as well first just to hear. You're right about the cabinet. I wish we had some ZMA and FRD files for these original woofers.
 
Only thing I can offer, DATS also does an impedance sweep of the woofer. I'm considering doing the mid "squawker" and tweeter as well.

I suppose one of the reasons I'm not overly concerned about bass output is that I've become so accustomed to the 8" bucket sub running with them for so long. It blends in so well, I doubt I'll remove it. I just want these doing best they can. I'm already on overkill for the caps for one pair.
 

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Any chance you have tried this yet ?
" I'm going to add a 1.5mh coil with RC (50uf !! and 7.5ohmR) and stock woofer and see what that does before I consider a replacement. The size of these cabinets is going to limit any of the low end output, but I think this approach will clean it up quite a bit with a recap on the factory crossovers.[/QUOTE] "

Think I'm going see how this works out for you before I replace the woofers, going to go ahead and recap the cross overs.

Not an expert at this, but this is the woofer I was considering for my 2500s: https://www.parts-express.com/dayton-audio-dc300-8-12-classic-woofer--295-320 Sealed, it's ideal for the 2500 cabinet.

I think what will hurt any replacement is the lower efficiency of choices.
 
Not yet, I have the inductors, but waiting on the caps and resistors to get in. Hoping to have this done next week. I'm not expecting miracles, just a clean up of what's there.
 
Got one board made up tonight and installed. Jantzen 1.5mh 15AWG Pcore coil, Dayton 50uf cap, Mills 7.5ohm resistor.

First, I know going in this will not be a cure all for missing low end. What did happen is cleanup in the lower mid/upper midbass region and it did tighten bass notes up. Allowed me to play with tone controls a bit more to get clean bass, instead of muddy tone boom. Vocals lost something I hadn't noticed before, until an A-B test between modded and un-modded. The old setup sounds more like singing through a large coffee can, vocals now come clean and accurate. Even my kid, who has no interest in these, noticed the difference. Enjoyed listening minus the subwoofers. I think I could actually ditch the 8" midbass sub I was using now.

Again, not an amazing cure all, but definitely noticeable. Can't wait to recap the crossovers now. Back to work on the second board.
 
Sounds like a positive improvement. :) Any chance you could take a few pics and post them for folks like me that aren't the sharpest ones on this stuff ? lol


Got one board made up tonight and installed. Jantzen 1.5mh 15AWG Pcore coil, Dayton 50uf cap, Mills 7.5ohm resistor.

First, I know going in this will not be a cure all for missing low end. What did happen is cleanup in the lower mid/upper midbass region and it did tighten bass notes up. Allowed me to play with tone controls a bit more to get clean bass, instead of muddy tone boom. Vocals lost something I hadn't noticed before, until an A-B test between modded and un-modded. The old setup sounds more like singing through a large coffee can, vocals now come clean and accurate. Even my kid, who has no interest in these, noticed the difference. Enjoyed listening minus the subwoofers. I think I could actually ditch the 8" midbass sub I was using now.

Again, not an amazing cure all, but definitely noticeable. Can't wait to recap the crossovers now. Back to work on the second board.
 
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Yeah, meant to take a pic of that first one before I put the back of the speaker back on. Will do that today.
 
Ok, some pre install/solder pics:

I got my values for the capacitor and resistor using the calculator on this page, and entering my values from the Dayton DATS program: http://www.apicsllc.com/apics/Misc/filter2.html

I stayed with the 6ohm rating, and used my Le value from the T/S ~1.768mh. To get the henry value, I simply moved the decimal three places to the left or .0018 (rounding up). That gave me a 50uf cap and 7.5ohm resistor. I probably overkilled this by using the Dayton cap, I think simple electrolytic would be fine here, but what the heck, right? If you're going to setup a Zobel for yours, I think you'd want to try to find T/S specs for that woofer you're using.

Looking at the diagram on that page for the Zobel (or RC circuit), the cap and resistor run across the + and - wires to the woofer. I laid out everything on my board, marked and drilled holes for zip strips, and the secured my Zobel. I will solder once installed to the speaker cabinet back: In the photo, the 3 way spade will be my negative input from the crossover, and negative out to the speaker:

20171229_082100 by Steven Ragan, on Flickr

I then placed my coil. Again, using this page to calculate the value I wanted for the low pass: http://www.apicsllc.com/apics/Misc/filter1.html A 1.5mh coil gave me a cutoff at roughly 640, which should (I think) match up fine for the 700hz bandpass at the midranges. 1.2mh runs up to almost 800, which for me would have been too high, but likely would work fine as well.

Here's a pic of placement and explanation. In a 6db crossover, the coil runs in line with the positive lead to the speaker. The lower 3 way spade in the pic will be the attachment in from the crossover network. The middle or upper 3 way spade will be the positive lead out to the speaker. Again, once I install the board to the speaker cabinet back, I'll solder all connections and attach the wires.

20171229_082157 by Steven Ragan, on Flickr

I thought I had enough room to use these boards in my cabinet, but alas no. Intentions were to install this directly next to the Woofer Out of the crossover. I ended up having to place them below the crossover network, almost directly behind the woofer. Had I known this, I probably would have just used plastic pipe clamp hold downs and used brass wood screws mounting each piece, and spades, directly to the back. No matter, I know this works as is. I've upgraded the internal speaker wire using DIY outdoor extension cord. Wire from the low pass to the crossover is 10 gauge solid core wire. Something you may also want to consider is using Rope Caulk weatherstripping along the inside edge where the cabinet back mounts to the speaker enclosure. Works fantastic, I had to pull my crossovers out and use my hand to hammer the back off the speaker. Will give you a nice seal on the cabinet.

Please understand, this is the first time I've assembled anything like this, and my second soldering adventure. I understand the concept, but did a lot of reading and looking at various odd pictures to be sure I understood the layout. If I could do it, anyone can.

Hope that helps!
 
Nice and neat. My inductor is inline between the woofer and crossover. The zobel is across the woofer terminals. I did go cheap on the zobel capacitor, lol. The whole set does calm down that woofer rather than straight to the amp with no prophylactic.
 
Yeah, I splurged on that, but what the heck, right? Wait til you get a load of the caps going into the crossovers! LOL

Cornell Dublier 940C 2.2uf
Cornell Dublier 940C 4.7uf
Obligatto Gold 10uf

My whole-hearted attempt at what some would believe "polishing a turd". Why not? I like my 2500s a lot!

We'll see. I have to construct standoffs for the caps so they'll fit properly. I may, may, try Modge Podge on the mids.

I've got to finish my SP2500 center channel project first. That's getting a mix of Audyn, Solen and Vishay bypass caps. I have to separate the mid/tweeter from the woofer into 2 separate cabinets to fit my TV stand, and I'm using a Faital Pro 6.5" woofer. That woofer will get a 2.0mh coil, 7.5uf cap and 10ohm resistor.
 
Going back to the original crossover layout, I'm curious about the advertised crossover points. The tapped inductors most likely change the crossover frequency, rather than attenuate it. High pass looks more along the lines of 7000hz or so, and I can't for the life of me work out the bandpass for the mids. I'm basically using a couple of online calculators and plugging in frequencies to get values close to what is there for a 12db crossover point.

I'm going to dust off my Algebra skills and try to figure it out using the existing component values.

When you measured the coils, were you able to get a rsistance value on them? I'm willing to bet it'd be easy to put together a crossover and eliminate the pots in these and used a fixed point.
 
Going back to the original crossover layout, I'm curious about the advertised crossover points. The tapped inductors most likely change the crossover frequency, rather than attenuate it. High pass looks more along the lines of 7000hz or so, and I can't for the life of me work out the bandpass for the mids. I'm basically using a couple of online calculators and plugging in frequencies to get values close to what is there for a 12db crossover point.

I'm going to dust off my Algebra skills and try to figure it out using the existing component values.

When you measured the coils, were you able to get a rsistance value on them? I'm willing to bet it'd be easy to put together a crossover and eliminate the pots in these and used a fixed point.

Have you seen this thread ? Read post #16, I was seriously considering doing this. Personally, the L Pads in any position other than normal and my speakers sound like crap to me. I hate the spring clip binding post, would love to get rid of them.

http://audiokarma.org/forums/index.php?threads/re-cap-sp-1700-speakers.276775/
 
Yep, have seen that post specifically too.

Right now I'm trying to figure out if this is a normal bandpass, or a Narrow Bandpass due to the layout on the board. Values are really odd trying to nail down a frequency range using existing values. It's looking like the crossover points are in the 1800hz-4000hz range for the mids, with a 6200hz crossover point on the tweeter. It's laid out (in the figure posted earlier) more like a Narrow Bandpass layout, and I'm trying to figure out the crossover points if it is.

Since I'm having a hard enough time figuring out the bandpass, I doubt I'd want to just toss in a cap and increase the impedance on a whim. Before I go messing with that, I really want to figure out what's going on with the stock crossover first, then play with it.

Original idea was to split the difference between clear and natural for the coil (.215 for the tweeter) and add the 2.2uf capacitor there. Then, same for the mid (1.52mh coil) and the 4.7uf. I'd leave the 10uf and .348 coil in place. That way I could put a new case back on, ditch the factory crossover switches, and seal the cabinet much better.

Of course, I could just make my own, and not worry about the factory values at all.......

Oh, I am working on trying to get rid of the spring clips as well. I found some short banana binding posts that may just work. It's whether I want to drill one of the boxes and find out that's stopping me.
 
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Going back to the original crossover layout, I'm curious about the advertised crossover points. The tapped inductors most likely change the crossover frequency, rather than attenuate it. High pass looks more along the lines of 7000hz or so, and I can't for the life of me work out the bandpass for the mids. I'm basically using a couple of online calculators and plugging in frequencies to get values close to what is there for a 12db crossover point.

I'm going to dust off my Algebra skills and try to figure it out using the existing component values.

When you measured the coils, were you able to get a rsistance value on them? I'm willing to bet it'd be easy to put together a crossover and eliminate the pots in these and used a fixed point.

This is where I started out with the thread. I didn't have enough know-how and sort of just gave up on figuring that out. I do know that the 16 Ohm resistor only works on one setting with the tapped inductors. This is far as a got with the inductors... SP1200, 1700, or 2500 Crossover Diagrams
 
That's why I wanted to get back on topic. As far as the resistor goes, I'm leaning towards the other poster in that it may be taming the switch itself, and not related to the crossover. Then again, I could be wrong and it is adding impedance to both the tweeter and the mid. This is all new-ish to me, and I have no idea how to figure that one out.

Using just the tweeter section, and the 3 coil values from the switch, I come up with (using the 14 ohm rating in parallel - 7 ohm [6.5 ohm if using the R(e) values of 13.02ohm]) frequency cutoffs are 6210 (.298), 9339 (.132) and 17182 (.039) combined with the 2.2uf cap. Or half octave from clear to neutral, full octave from neutral to soft provided I'm understanding crossover frequencies in general.

Running 2 different narrow bandpass calculators, since the layout in the schematic seems to be just that (see image) the closest I can get to the values of the components is 1250 high pass and 5200 low pass (L1=.82mh C1= 4.75uf and L2=.341mh C2=11.4uf) I cannot get frequencies to match the existing components any closer than that. That's using the 6ohm parallel rating (4.9 using the 9.828 ohm R(e) rating)

nbpass12db.gif


I may experiment with the center channel project, unless someone smarter explains the resistor in this setup. I may be off, but if the tweeter is in series with the mid, but parallel with the woofer, that keeps us at an overall 8ohm rating for the speaker, yes?
 
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