This is probably a really dumb questions but I keep reading that the mtm should have the tweeter as close as possible to the woofer. Also a off center tweeter helps with edge diffraction. If I move the tweeter off center and wolfers closer to each other does that mean a complete redesign of the crossover? probably not worth worrying about especially for a first build.
Thanks
Thanks
It depends on a number of things WRT insulation, manufacturing tolerances, but if you buy wire that meets the various UL/CSA requirements, none of them should be an issue.
For instance, a few weeks ago I found a pair of 15 ft long 16 ga brown lamp cord with silver soldered ends I used back in '69 and compared them with the same in white I bought in '94 except bare ends and all runs measured 0.5 ohm with a one time professionally calibrated digital multi-meter.
Wire sizing is about voltage drop over distance [round trip, not one way], so the longer the run and/or the higher the current draw, the larger the wire needs to be.
GM
How many strands in the 12ga?
More the better.
12 ga. may be a little over kill, but shouldn't hurt anything either.
XO on the outside of the speaker, right?
Here is what I have from my XO to the binding posts.
One set of binding posts for the woofers, one set for the tweeters. You should consider doing this too IMO. Keep the (-) separate too. I'm happy I did. Future Proof.
I have 2 runs of pure (enough) silver 20ga. in Teflon for the tweeters. 2 for the positive, 2 for the negative. (no problems yet Sy)
4 strands of 26ga. (8 total) solid Cat 6 copper in Teflon (plenum grade) for the woofers.
From the binding posts to the drivers is the same format.
I used 16 ga silver plated copper inside the XO. It's what I had on hand at the time.
Just showing what I did, not saying it's right.
Pictures are showing the backside of the baffle routed out (different speaker build) and my Thor XO.
Ron
More the better.
12 ga. may be a little over kill, but shouldn't hurt anything either.
XO on the outside of the speaker, right?
Here is what I have from my XO to the binding posts.
One set of binding posts for the woofers, one set for the tweeters. You should consider doing this too IMO. Keep the (-) separate too. I'm happy I did. Future Proof.
I have 2 runs of pure (enough) silver 20ga. in Teflon for the tweeters. 2 for the positive, 2 for the negative. (no problems yet Sy)
4 strands of 26ga. (8 total) solid Cat 6 copper in Teflon (plenum grade) for the woofers.
From the binding posts to the drivers is the same format.
I used 16 ga silver plated copper inside the XO. It's what I had on hand at the time.
Just showing what I did, not saying it's right.
Pictures are showing the backside of the baffle routed out (different speaker build) and my Thor XO.
Ron
Attachments
Thanks all
the wire is teflon coated multistrand silver plated ofc. It is a far better price than anything I can buy retail. So even though its pretty heavy as long as it will not hurt anything I am going to go for it.
While getting ready to lay out the speakers on the baffles I noticed that one of the mids has a tear in the surround. I have some of the glue that you use to replace the surrounds from a Salvation army 5.00 BA speaker I bought and replaced the surround on. I could try glueing it? is there some other way to fix? I replaced the surrounds on a 5.00 speaker dont really want to do it on a speaker of this caliber. will it hurt anything can I just leave it?
Here is a build update
I have been thinking about how to cut the circles and finally after reading several areas made a circle cutter. I used a concrete screw anchor plastic and the first one did fine on the scrap piece the second hole I did the anchor flew out once i taped the anchor is it worked really well. Even though all I got done today is the flange area it was good to figure out a method. they came out ok for the first ones. Here are pics.
And another question. I am going to order a 3" port are they exactly 3" I would like to finish the baffle before the ports get here.
Thanks again
the wire is teflon coated multistrand silver plated ofc. It is a far better price than anything I can buy retail. So even though its pretty heavy as long as it will not hurt anything I am going to go for it.
While getting ready to lay out the speakers on the baffles I noticed that one of the mids has a tear in the surround. I have some of the glue that you use to replace the surrounds from a Salvation army 5.00 BA speaker I bought and replaced the surround on. I could try glueing it? is there some other way to fix? I replaced the surrounds on a 5.00 speaker dont really want to do it on a speaker of this caliber. will it hurt anything can I just leave it?
Here is a build update
I have been thinking about how to cut the circles and finally after reading several areas made a circle cutter. I used a concrete screw anchor plastic and the first one did fine on the scrap piece the second hole I did the anchor flew out once i taped the anchor is it worked really well. Even though all I got done today is the flange area it was good to figure out a method. they came out ok for the first ones. Here are pics.
And another question. I am going to order a 3" port are they exactly 3" I would like to finish the baffle before the ports get here.
Thanks again
Attachments
Too bad the surround is torn, I would sure ask a LOT of questions before trying anything myself. Dave can answer that question for ya.
The port tube can be aquired from Home Depot or Lowes CHEAP. Standard 3" ABS pipe works perfectly. On the back side of the baffle route out an indent the same size or a little bit bigger than outside of the ABS pipe. Glue or epoxy the pipe in place and trim the hole with a flush cut router bit. Then use a roundover bit for the outside of the flare. Blamo. Done. Clean and professional looking.
Good job on making your own template.
Looks good, it's coming along nicely. Have a good Thanksgiving.
Ron
The port tube can be aquired from Home Depot or Lowes CHEAP. Standard 3" ABS pipe works perfectly. On the back side of the baffle route out an indent the same size or a little bit bigger than outside of the ABS pipe. Glue or epoxy the pipe in place and trim the hole with a flush cut router bit. Then use a roundover bit for the outside of the flare. Blamo. Done. Clean and professional looking.
Good job on making your own template.
Looks good, it's coming along nicely. Have a good Thanksgiving.
Ron
Depends. Consider the electrical power typically required to drive a woofer. A single strand is the ideal, but isn't practical in most apps, so number of strands is about how flexible it needs to be to route it plus due to internal losses it ideally needs to be derated, same as happens when multiple vents are used instead of one large one.
The tweeter OTOH will be 'feeling' the need for much less power, ergo it doesn't need nearly as big a single cable and why magnet winding wire is a near ideal choice, so woofer size wiring will act as a shunt unless it is made with the appropriate size, minimum number of strands optimally required for HF transmission. In this scenario, you’re right, the more strands, the better as they will be smaller.
How far out of whack the mismatch before it's perceived depends on speaker efficiency, peak SPL required, room acoustics, but I don't recall ever seeing even a rule-of-thumb, so only know to calculate theoretical ideals, though I guess with today's measurement systems it can probably be seen by comparing high resolution impulse responses or....?
GM
Can you please explain this? Frankly, I do not understand why a single strand would be better. From what I've read the signal (electrons) travels (really just nudge into each other) on the outside surface of the wire, not the inside. Multiple strand wire has a greater surface area than single strand wire.
I don't want to get into a debate here, just trying to understand.
We're not talking about more than meter or so worth of wire.
Ron
Poor packaging then. That is on the seller.
It can be glued but it will never be as good as it could.
dave
But given a single strand, all the other strands are interfering with the field on the outside of the conductor. Ideally each wire would be surrounded by a vacuum but since that is not practical, insulators with diaelectrics that come closet to a vacuum are best.
dave
Addendum. The factory packaging i have seen from SEAS is less then stellar -- minimal. And they rely on little plastic bits that plug into the bolt holes to keep the cardboard wrap from squishing/damaging the surround. These are easy to lose, and if the seller didn't think ahead to where he was going to resell these, then he likely lost/tossed tham and didn't use anything (i'm guessing -- snapped off golf tees are a good sub if the bolt holes are large enuff). The surround could esiely have stuck to the packaging and then when removed ripped a bit of surround off.
IME far too many people shipping drivers have no clue. And you cannot assume that the factory packaging is up to the task. I often reinvent the packaging before shipping drivers out.
dave
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