resistors

[davepellegrene]

I was looking at the Impresio speakers in the showcase. I was matching the parts list to the crossover drawings and I notice there are three resistors in the parts list and six in the crossover drawings. What am I not understanding?

[fuzzy]

> The resistors in the parts list are real, the others are the DCR of the inductors.

[davepellegrene]

I just learned what capacitors,resistors and inductors are for. Could you elaborate on DCR?

[ericanderson]

> I just learned what capacitors,resistors and
> inductors are for. Could you elaborate on
> DCR?
Direct Current Resistance this is the resistance the amp sees at DC in an inductor eric

[davepellegrene]

[davepellegrene]

> Direct Current Resistance this is the
> resistance the amp sees at DC in an inductor
> eric
I see the ones that are not in the parts list are in front of the inductors. Thanks for the info.

[Chris Roemer]

> I see the ones that are not in the parts
> list are in front of the inductors. Thanks
> for the info.

What people are trying to say, is that (in general) a capacitor passes high freqs., but doesn't impede the lows. An inductor (coil) blocks highs and lets the lows through. The thing is, that ALL the low freq. energy doesn't pass through (like almost all the highs do on a cap) because an inductor is a long (possibly hundreds of feet?) piece of what COULD be small gauge wire (you see 14# - expensive, 15#, 18#, and cheap 20# - smaller wire) and the RESISTANCE (DCR) in that wire robs power (voltage drop) to the woofer which is usually the least efficient (dB SPL) driver in a system.

You can get the same effect by using either a 14# coil ($) with a 1 ohm or 2 ohm resistor in line with it, OR a cheap (#20) coil made with small wire that will have an ohm or 2 of resistance built in! Many designs SHOW you the DCR of the coil that was used rather than specifying the gauge of the coil. That DCR looks like a resistor in the schematic, but it is NOT a seperate component in the XO.

Chris

[davepellegrene]

> What people are trying to say, is that (in
> general) a capacitor passes high freqs., but
> doesn't impede the lows. An inductor (coil)
> blocks highs and lets the lows through. The
> thing is, that ALL the low freq. energy
> doesn't pass through (like almost all the
> highs do on a cap) because an inductor is a
> long (possibly hundreds of feet?) piece of
> what COULD be small gauge wire (you see 14#
> - expensive, 15#, 18#, and cheap 20# -
> smaller wire) and the RESISTANCE (DCR) in
> that wire robs power (voltage drop) to the
> woofer which is usually the least efficient
> (dB SPL) driver in a system.

> You can get the same effect by using either
> a 14# coil ($) with a 1 ohm or 2 ohm
> resistor in line with it, OR a cheap (#20)
> coil made with small wire that will have an
> ohm or 2 of resistance built in! Many
> designs SHOW you the DCR of the coil that
> was used rather than specifying the gauge of
> the coil. That DCR looks like a resistor in
> the schematic, but it is NOT a seperate
> component in the XO.

> Chris

So does that mean the heavier wire is going to let more high frequency through than a smaller more resisting wire? So wouldnt it be best to use the heavier wire and make it as long as needed to block out whatever frequency you are trying to block? Would this make your speaker more efficient?
Dave

[Chris Roemer]

> So does that mean the heavier wire is going
> to let more high frequency through than a
> smaller more resisting wire? So wouldnt it
> be best to use the heavier wire and make it
> as long as needed to block out whatever
> frequency you are trying to block? Would
> this make your speaker more efficient?
> Dave

Nope. We're talking about the coils (inductors) here. They block highs. Unfortunately, the smaller gauge ones (which cost less) also suck up the bass (voltage, actually). It would usually be BEST to use the biggest ones, but they cost a heck of a lot (more than a lot of drivers).

[davepellegrene]

> Nope. We're talking about the coils
> (inductors) here. They block highs.
> Unfortunately, the smaller gauge ones (which
> cost less) also suck up the bass (voltage,
> actually). It would usually be BEST to use
> the biggest ones, but they cost a heck of a
> lot (more than a lot of drivers).

Ok.Thanks for clearing that up. I guess were I am at now. I would like to build these speakers but I have never built a crossover. Not sure I can, yet. Would I be better off buying a prebuilt crossover or would that completely change the sound of the speakers. Might be better than screwing up a crossover. Seems like that would take a lot of the fun out though.
Also is there anyway to get a picture on the layout of the crossovers. From what I have been reading the placement and direction of the parts are critical.

[johnastockman]

http://custom.smugmug.com/photos/186607288_8dwEr-L.jpg


> Ok.Thanks for clearing that up. I guess were
> I am at now. I would like to build these
> speakers but I have never built a crossover.
> Not sure I can, yet. Would I be better off
> buying a prebuilt crossover or would that
> completely change the sound of the speakers.
> Might be better than screwing up a
> crossover. Seems like that would take a lot
> of the fun out though.
> Also is there anyway to get a picture on the
> layout of the crossovers. From what I have
> been reading the placement and direction of
> the parts are critical.

Dave, Curt has a great write-up on how to get from a schematic to a working XO:

<A HREF="http://www.geocities.com/cc00541/nodal_analysis.html">http://www.geocities.com/cc00541/nodal_analysis.html</A>

I was a total dunce when it came to reading a schematic and translating the diagram to a XO that worked. What I used to do was lay out the parts according to the diagram...this cap horizontal, this coil vertical, etc. A physical representation of the diagram with the leads touching each other. I just soldered where the component leads touched. They were huge! But they worked. Now, with some experience under my belt, I can lay out the parts and conserve space, usually getting a tweeter or a woofer XO on a 3" x 5" or 4" x 6" piece of hardboard.

Plus, there's a lot of nice folks here that can help you along, like they did with me when I started out.

Take it from someone who has been down the frustrating road of trying to get textbook and pre-made XO's to work (that was before I found the wealth of knowledge here about 8 years back)...you'd be screwing up your design much more by using a pre-made XO. The only thing that is important AFA placement goes is the orientation of the coils (inductors). You don't want to have two coils too close to each other. Other than that, the coils, resistors and caps used in XO networks aren't polarized. That is they don't have an "in" or "out" or positive/negative. Here's a pic of one of my networks, with the diagram on the right and the actual XO on the left with the components labeled. If it's still a bit confusing, I understand, I've been there. Don't be afraid to ask for help...no ? is dumb or too simple. I have a lot of pics of my XO's and I could put together a few more pics with the diagram next to the real XO and label the pieces. Maybe start out with a simpler arrangement.

John A.

[philiparcario]

Provided Link: EUROPEAN CONNECTOR STRIP (http://www.mcmelectronics.com/product.asp?product_id=28-995&catalog_name=MCMProducts)


> Dave, Curt has a great write-up on how to
> get from a schematic to a working XO:

>
> <A HREF="http://www.geocities.com/cc00541/nodal_analysis.html">http://www.geocities.com/cc00541/nodal_analysis.html</A>
> I was a total dunce when it came to reading
> a schematic and translating the diagram to a
> XO that worked. What I used to do was lay
> out the parts according to the
> diagram...this cap horizontal, this coil
> vertical, etc. A physical representation of
> the diagram with the leads touching each
> other. I just soldered where the component
> leads touched. They were huge! But they
> worked. Now, with some experience under my
> belt, I can lay out the parts and conserve
> space, usually getting a tweeter or a woofer
> XO on a 3" x 5" or 4" x
> 6" piece of hardboard.

> Plus, there's a lot of nice folks here that
> can help you along, like they did with me
> when I started out.

> Take it from someone who has been down the
> frustrating road of trying to get textbook
> and pre-made XO's to work (that was before I
> found the wealth of knowledge here about 8
> years back)...you'd be screwing up your
> design much more by using a pre-made XO. The
> only thing that is important AFA placement
> goes is the orientation of the coils
> (inductors). You don't want to have two
> coils too close to each other. Other than
> that, the coils, resistors and caps used in
> XO networks aren't polarized. That is they
> don't have an "in" or
> "out" or positive/negative. Here's
> a pic of one of my networks, with the
> diagram on the right and the actual XO on
> the left with the components labeled. If
> it's still a bit confusing, I understand,
> I've been there. Don't be afraid to ask for
> help...no ? is dumb or too simple. I have a
> lot of pics of my XO's and I could put
> together a few more pics with the diagram
> next to the real XO and label the pieces.
> Maybe start out with a simpler arrangement.

> John A.
YOU CAN use euro connectors like these but the 12 size and cut them down. you can avoid solder

[davepellegrene]

> Dave, Curt has a great write-up on how to
> get from a schematic to a working XO:

>
> <A HREF="http://www.geocities.com/cc00541/nodal_analysis.html">http://www.geocities.com/cc00541/nodal_analysis.html</A>
> I was a total dunce when it came to reading
> a schematic and translating the diagram to a
> XO that worked. What I used to do was lay
> out the parts according to the
> diagram...this cap horizontal, this coil
> vertical, etc. A physical representation of
> the diagram with the leads touching each
> other. I just soldered where the component
> leads touched. They were huge! But they
> worked. Now, with some experience under my
> belt, I can lay out the parts and conserve
> space, usually getting a tweeter or a woofer
> XO on a 3" x 5" or 4" x
> 6" piece of hardboard.

> Plus, there's a lot of nice folks here that
> can help you along, like they did with me
> when I started out.

> Take it from someone who has been down the
> frustrating road of trying to get textbook
> and pre-made XO's to work (that was before I
> found the wealth of knowledge here about 8
> years back)...you'd be screwing up your
> design much more by using a pre-made XO. The
> only thing that is important AFA placement
> goes is the orientation of the coils
> (inductors). You don't want to have two
> coils too close to each other. Other than
> that, the coils, resistors and caps used in
> XO networks aren't polarized. That is they
> don't have an "in" or
> "out" or positive/negative. Here's
> a pic of one of my networks, with the
> diagram on the right and the actual XO on
> the left with the components labeled. If
> it's still a bit confusing, I understand,
> I've been there. Don't be afraid to ask for
> help...no ? is dumb or too simple. I have a
> lot of pics of my XO's and I could put
> together a few more pics with the diagram
> next to the real XO and label the pieces.
> Maybe start out with a simpler arrangement.

> John A.
Thanks John. I was reading an article that told you to lay it all out on a board and twist it together then solder it. I wasnt sure if I should buy the fiberglass boards. One article they put it on a peice of carboard. The pic you sent looks pretty simple. I am still confussed on how to do a three way. Do they all fit on the same board and are some of the parts used for all three speakers?

[davepellegrene]

> YOU CAN use euro connectors like these but
> the 12 size and cut them down. you can avoid
> solder
Thanks Phillip. That write up helps a lot. Makes sense the way he tells you to lay it out. Those connectors are pretty slick.Its been a while since I have done any soldering but I think I can still do it. I have a pretty good back ground in plumbing. If I remember soldering, use just enough heat to make the solder, any more and other things start to melt

[davepellegrene]

> Thanks John. I was reading an article that
> told you to lay it all out on a board and
> twist it together then solder it. I wasnt
> sure if I should buy the fiberglass boards.
> One article they put it on a peice of
> carboard. The pic you sent looks pretty
> simple. I am still confussed on how to do a
> three way. Do they all fit on the same board
> and are some of the parts used for all three
> speakers?

Answered part of my own question:each speaker has its own parts they dont share any. That leaves the question do they all fit on one board or do you have three boards?

[johnastockman]

> Answered part of my own question:each
> speaker has its own parts they dont share
> any. That leaves the question do they all
> fit on one board or do you have three
> boards?

You can use one board, but I find it easier to use separate boards. It helps me keep track and organize the components. For me, I can decipher the diagram easier by having a separate diagram and board for each segment of the XO. You'll use a bit more lead in (from the terminal) and lead out wire. About a 30-40 watt pencil iron is fine for XO work. A gun that's upwards of 100 to 140 watts is too much for the small gauge leads on XO parts, especially on capacitors.

John A.