Replacing Magnavox 12" woofers with Celestion 10"

[greyhnd]

Good day folks.

I currently have some DIY speakers using Magnavox console 12" woofers and 4"x10" horns. One of the 12" woofers has come apart around the surround and no amount of glue has fixed it.

I ran across a pair of 10" Celestion woofers out of DL10 speakers on CL. Picked them up cheap and they're in nice condition. I plan to replace the 12's with the 10"ers.

The enclosures I'm using are 18"Hx15"Wx12D. The horns are mounted on top of the boxes. I've also been using the original crossovers and attenuation switches from the console to control the horns. They actually sound pretty darn good, but I can't use them the way they are.

What I'm trying to figure out is how to incorporate the Celestion woofers with the Magnavox horns. Would I be safe to continue using the old xovers and switches with this different combo? I'm guessing I'll need to make adjustments for the smaller woofers, but my electronics knowledge is limited so I'm a bit lost.

The only info I've found on the Celestion woofers are the following numbers.
On one speaker there are the numbers 8389Z and below that AT23. On the other woofer the only thing I see is JT11. Haven't found any parameters using those numbers. The only other bit of info I've found is the sensitivity ratng of 91db for the DL10 speakers.

Any suggestions? I'm trying to do this on low funds so be kind. Thanks in advance.

 

[cablephil212]

Let's start here. When you say x-overs, is the low pass incorporated into the board, or is it just for the horn? Are/were the woofers fed off the x-over?

At just over 1.8cu" of volume, it would be an "install and listen" kind of experiment. Since you have no T/S values for the woofers, make an adapter plate and mount the woofer.

This is a crap shoot. It might or might not work. The only way to find out is to do it. I'm assuming the old Mag woofers have paper surrounds. DON'T throw out the old woofers. You might be able to put a new surround on them.

 

[budd]

what he said

Let's start here. When you say x-overs, is the low pass incorporated into the board, or is it just for the horn? Are/were the woofers fed off the x-over?

At just over 1.8cu" of volume, it would be an "install and listen" kind of experiment. Since you have no T/S values for the woofers, make an adapter plate and mount the woofer.

This is a crap shoot. It might or might not work. The only way to find out is to do it. I'm assuming the old Mag woofers have paper surrounds. DON'T throw out the old woofers. You might be able to put a new surround on them.

Trust cablephil,saved me a lot of work and struggle:thmbsp:

 

[greyhnd]

cablephil - the xover of a resistor, a coil (wire wound) which are connected to the horns and a cap that is connected to the woofer. I've been trying to get the cap value, but can't get the xovers positioned so I can see the numbers.

My concern was the original Mag woofers are more full range than "real" woofers, although they do produce sufficient bass for my needs. The Celestion woofers were for low end production in the DL10's.

I'll do as you suggested, mount them up and give a listen. Will report back after listening to them. Thanks for the response. Much appreciated.

 

[greyhnd]

An update after some listening.


The horns and woofers are balanced pretty well, neither one drowns out the other. To my ears it seems that the Celestion woofers are struggling a bit to reproduce the mids with the clarity they reproduce the lows.

This is the part where I get mixed up about what xover component does what. I have some 12uF caps here left over from recapping a pair of Polk Monitor 7's. I also wonder if I should add a mid to the mix? Seems that might relieve some of the strain on the woofer? Then again I go from a 2way to a 3way and add to the problem. I have some mids here I bought from PE a couple years ago and never used. I get the number and see what I can find out. I also have a pair of old xovers from some Pioneer 3ways I might test and see how they sound.

 

[elliott66]

Greyhnd,

The cap should feed the horn, and the coil should feed the woofer. I hope you stated that backwards or you're sending the low stuff to the tweeter and the high stuff to the woofer! (it must be misstated or it would've sounded very strange).

You could try to add a mid to the mix but if you do that you'll want to cross over the woofer at a lower frequency so there's not too much overlap. Also the high end of the mid will have to rolled off at the tweeter crossover frequency. You'll have to design a new crossover for all that. You could try a generic 3-way crossover, if you can find a decent one with options for crossover points and are willing to experiment.

 

[cablephil212]

cablephil - the xover of a resistor, a coil (wire wound) which are connected to the horns and a cap that is connected to the woofer. I've been trying to get the cap value, but can't get the xovers positioned so I can see the numbers.

My concern was the original Mag woofers are more full range than "real" woofers, although they do produce sufficient bass for my needs. The Celestion woofers were for low end production in the DL10's.

I'll do as you suggested, mount them up and give a listen. Will report back after listening to them. Thanks for the response. Much appreciated.

OK. The only way to clear this up is, if you can, post a pic or 2 of the x-over. If possible, tag the wires so we know to what driver they go to. Get some top and bottom shots of the board so things can be traced out. It's possible the horn is a 2nd order slope, but a look at the x-over will confirm if it is or not.

Those horns are good down to about 800hz, so it's possible to swap some x-over parts to help with the midrange. Post some pics, and let's see what we can do.

 

[greyhnd]

elliot - thanks for the reply. I hate to add a darm mid, but may have to.

Cablephil - I'll snap some xover pics tomorrow since it's late here now. I'll also post pics of the horn attenuation switches which might help as well

 

[greyhnd]

cablephil - Alrighty, here are some pics of the xovers and also the original attenuation switches. I apologize in advance for my less than adequate pic taking skills.

There are two wires from the terminal block on the switch that go to the woofer +/- terminals. The white wire from the resistor goes to the horn +. The black wire from the coil goes to the - side of the horn and also Y's off with a - to the woofer. The white wire from the cap goes to the woofer + side.

I hope you can see things in the pics clearly, but if not I'll try to get you some better photos if needed.

It looks to me like the cap is 2uf 25V? The resistor on the xover says 15 ohm and the resistors on the switch terminal block appear to be 10ohm? I can't see any kind of markings on the coil, so I can't be of help there.

Hope this will help.
Thanks in advance.

 

[greyhnd]

cablephil - I forgot all about having a wiring diagram for the xover and switches. It is attached below.

I also have a link to an old PE page that shows the mids I have here in case I need them. I've also looked around a bit on that auction site and there are a few xovers that might be promising, although they may be more trouble than they're worth.

http://www.parts-express.com/pioneer-b11ec80-02f-5-1-4-cup-midrange--280-020

 

[cablephil212]

Hey greyhnd.

From the description it sounds D) like the woofer is run full range and the horn is a 2nd order, x'ed over at about 5>6k. That's kind of high, but well within the norm for that kind of combo.

I looked at the mid link, and that's a nice driver. If you wanted to incorporate it into the rest of the drivers, you'd have to design an all new x-over. I really don't think an "off the shelf" one would give good results. But don't let that stop you from trying.

If you have a RadioShack close, pick up (6) 10mdf non-polar caps. Take 2 and parallel them to get 20md. Temporarily wire up the mid with the caps on the positive side of the wire. Hook up the temp wire directly to the speaker terminal. Be sure to observe wire polarity, + to +, - to -. Prop the mid on top of the speaker. Play some music. If the mid is "too much in your face", add the 3rd cap, again in parallel, and try again.

You can make combo's of caps, from only 1, to all 3. This is where the fun comes in.

Give it a try. It won't cost much, and it might sound good.

 

[greyhnd]

cablephil - I bought those mid drivers a couple years ago and have never used them. I think I'll try your suggestion. You're right about not much cost wise and I have a RS about 10 miles from me.

This will sound stupid and maybe it's because I'm tired tonight. I know how to wire the caps in parallel, but to incorporate them into the scheme of things where do I connect them to get power? Will probably make more sense to me tomorrow, but it never hurts to make things clear to myself.

 

[cablephil212]

No problem in explaining it clearer. The cap(s) go in series with the positive (+) of the speaker wire and the positive (+) of the driver. The cap(s) can be placed anywhere along that feed.

Here's what I do when I test drivers out. I bought a bunch of alligator clips. I use them to hold the wire, cap, or coil onto the wire or driver lugs. Just put the wire or lead on, then use the clip to make the connection. Fast, simple, and no need to solder anything. The nice thing about this is you can swap parts in and out, and try different combinations before the final assembly. Once you're happy with what you have, solder away. Just be CAREFUL nothing shorts out.

When you get the caps from RadioShack, pick up 8 alligator clips. They can be used for more than testing, and are handy to have around. Think of it as building up your test equipment. Also, if you don't have a meter, it would be something to think about getting. Lots of uses in speaker building and testing.

So, to recap, take the leads from the cap(s) and clip them to the + lug on the driver. Next, take your speaker wire and clip the - to the driver, and the + to the other end of the cap(s). Then take the other end of your speaker wire and attach it to the box terminals, observing polarity.

Hope that's clear enough. Anything else, post it up.

Now go have some FUN. :thmbsp:

Phil

 

[greyhnd]

cablephil - Got home from RS about 30 minutes ago. They had 8 caps in stock, so I took 6 of them. I already have a bunch of alligator clips in different sizes, both insulated and non. I also have a multi tester here that I've had for a few years.

I'm clear on the wiring now and thanks for the explanation. I was tired last night and couldn't get things thru my thick skull. I'm not sure if you can tell from the picks I posted, but do I need to attach the speaker wires to the terminals or to the terminal block that's on the back of the attenuation switches? There are 2 empty spade terminals on the speaker connection terminals, is that where I need to connect them? If on the terminal block, do you know which ones I should use?

Sorry to be so difficult. If I don't ask and/or experiment I'll never learn the things I need to know.

** Just as a side note, I use foobar for my music playback and I forgot about it having a decent EQ included. I played some tunes and adjusted the mids up a bit and dialed the bass back a bit. It helped, but not nearly as much fun as experimenting with the drivers.

 

[cablephil212]

greyhnd.

No problem. Asking questions is the way to gain an understanding of the problem, and the solution. We've ALL been there. You gotta start somewhere, right?

For testing the mid, you want to go directly to the terminals on the speaker box, where the wires comes from the amp to the speaker. By using the cap(s) for the "add-on" mid, it creates its own x-over. Anywhere else you tap off of might screw up the x-over frequency of not only the mid, but the rest of the drivers in the box.

What you're trying to do is make a 2way into a 3way D) without soldering or modifying the original for testing purposes.

Just come off the box terminals with the wires for the mid, place the cap(s) in line with the + lug on the mid, and power it up. Again, keep the polarity the same for the wires off the box terminal to the mid.

Alrighty then. GET TO WORK. LOL

 

[greyhnd]

cablephil - For heavens sake. I should've figured that out on my own, but I was trying to make some thing easy, difficult.

Right now I have the mids hooked up using only 1 cap. They aren't harsh or overbearing, but still not wquite right. I'm going to listen to them this way for an hour or so then add a 2nd cap. I went into Foobar and 0'd all the eq settings flat, so as not to color the sound in any way at the start. I'm glad you mentioned using the alligator clips, makes testing a piece of cake.

Don't want to be too long winded here. Last evening I did some more searching on the DL10 woofer. Still no T/S parameters that I can find, but I did see that the DL10 speakers have a rear firing port. I have half a notion to put a port in the cab I have, but getting it right will be a stab in the dark. Celestion is/was a popular speaker maker, so there have to be parameters out there somewhere. I also think we have a member here on AK that is experienced with many of the European speaker manfacturers, I just can't remember who it is.

These are just play cabinets and I'll make new ones when I get the sound I want figured out. Thanks so much for all the help. I might just make myself some sweet sounding spks after all.

 

[greyhnd]

Added a 2nd cap and that has smoothed the sound more to my liking.

 

[cablephil212]

Hey. Havin' fun yet?

You could also use a couple of different values of resistors in your arsenal to tame a hot driver. Like these: http://www.parts-express.com/cat/general-purpose-resistors/1528. RS sells them also.

Stop back to RS, and buy 2 of each: 1 ohm, 2 ohm, 4 ohm, and 8 ohm. With these, you can find the right attenuation using a single or multiple resistors to "pad" down a drivers output.

FYI: When adding resistors together for a higher value, they get put in SERIES, not parallel. That is the way to add resistance to the feed of the driver. ALSO, the resistor(s) go BEFORE the cap(s). They come off the drivers feed, then the cap(s) follow.

By adding resistors in line, it's like having a pot (L-pad) to adjust the amount of voltage going to the driver. The only drawback is you can't just turn the knob to balance the output. You have to add (or remove) resistors to get the right balance.

For testing tho, it's an easy way to get an idea of what's needed to have all the drivers balanced.

Later.

 

[greyhnd]

cablephil - Yup, I'm honestly having a blast messing with these things. I need to go to Home Depot which is about 500 yards from RS, so I'll swing by and pick up some assorted resistors. The Pioneer mids actually sound pretty nice, just don't have the right balance between the drivers just yet.

I'm glad you mentioned putting the resistors in series. I'd have screwed that up and then wondered why it didn't work like it should....lol.

 

[cablephil212]

Hey, that's what this hobby is all about. Fun. :thmbsp:

I was going to suggest to try all 3 caps for the mid. The more caps, the lower the x-over will be. With 3 (30mdf), the mid should cross over at about 700mhz. That is well within the drivers range.

If it sounds like there's too much lower midrange (voices sound kinda raspy), stop back at RS and pick up (2) 4.7mdf caps. At 25mdf, you're about 800mhz low end on the mid. This might bring it more in line with the roll-off of the woofer.

Again, it's all about experimentation. Swapping parts in and out 'till you're satisfied with the sound quality.

OK, back to the Fun.