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PostPosted: January 2nd, 2019, 5:08 pm 
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FerdinandII wrote:
tomp wrote:
The tabs are 1/4" "Faston" style spade lugs that I pulled off some old IBM equipment. They make a great way to connect the amp and drivers to the boards. I have lots if you need a few. I just drill a hole in the board and screw them down with a connecting lug under the screw. If you need to remove the boards for modifications you only have to lift the mating connectors off the lugs. You would need 1/4" female connectors to use with them and again there are tons of places on ebay that offer them at reasonable prices often with free shipping. Here is just one example of a connector with free shipping. They come in different sizes and with or without insulation. I keep a supply of male and female in different sizes both insulated and not on hand as they are always in use:

https://www.ebay.com/itm/100-Vinyl-Fema ... rk:26:pf:0


Or visit your local auto parts store. They will have a good selection in small quantities.


Even Walmart. First thing I did was buy a pack and some cheap speaker wire.

Got tons of wire ties to secure everything. I just don't have any type of mounting board.


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PostPosted: January 2nd, 2019, 5:40 pm 
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Lots of options at the hardware store

https://www.homedepot.com/p/Plaskolite- ... /301109740

You can also buy a cheap clipboard from Target, or Walmart. Cut out the boards from there.

https://www.target.com/p/saunders-plast ... A-15339613

Two for $8!


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PostPosted: January 2nd, 2019, 5:46 pm 
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FerdinandII wrote:
tomp wrote:
The tabs are 1/4" "Faston" style spade lugs that I pulled off some old IBM equipment. They make a great way to connect the amp and drivers to the boards. I have lots if you need a few. I just drill a hole in the board and screw them down with a connecting lug under the screw. If you need to remove the boards for modifications you only have to lift the mating connectors off the lugs. You would need 1/4" female connectors to use with them and again there are tons of places on ebay that offer them at reasonable prices often with free shipping. Here is just one example of a connector with free shipping. They come in different sizes and with or without insulation. I keep a supply of male and female in different sizes both insulated and not on hand as they are always in use:

https://www.ebay.com/itm/100-Vinyl-Fema ... rk:26:pf:0


Or visit your local auto parts store. They will have a good selection in small quantities.


Probably cost more than the ones on ebay and also usually only come in assortments, most of which you will not use. I recently needed a replacement tire valve stem insert for one that was leaky on my car. The local Autozone had one for$3.50 plus tax and the time and gas to drive to the store and back. Ebay had a pack of 100 for $7.00 with no tax or shipping. I kept some and gave the rest to friends and family.


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PostPosted: January 2nd, 2019, 5:55 pm 
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Here is an example of why I buy connectors on ebay. The link I posted before about ebay had 100 female 1/4" connectors for $6.85 with no tax or shipping. One of the connectors from Autozone costs $5.99 and they are out of stock.


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Dorman Conduct-Tite female quick slide terminal 84546.pdf [1.39 MiB]
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PostPosted: January 2nd, 2019, 7:29 pm 
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Location: Parkville, Maryland
Cogito wrote:
Pelliott321 wrote:
The right question to ask is if one could really hear the differences in .05 mph changes


Electricity and magnetism are inseparable. Inductors are nothing but a piece of wire coiled to accumulate the magnetic forces generated by the electricity following in the wire into a single magnetic field (common poles). This accumulated magnetic field is the heart of an inductor.

The inductors in the high pass and low pass sections of the crossover work over a different frequency ranges. When the magnetic field one inductor interferes with the magnetic field of another, it creates unintended effects on the charge and discharge rates of the inductor. These charge and discharge cycles are the frequencies passing thru the inductor.

The author of that study connected the inductors in series to measure the overall effect of EM interference. It doesn’t say what the effect on the inductors is when both are operating at different frequency ranges are of different strengths.


If one is learning the basics of electricity/electronics it is important to study reference material and stay the hell away from Wikipedia.

Whoever contributed to Wikipedia should have resisted the impulse.

An inductor does not store energy, but the inductive reactance can attenuate certain AC frequencies based on the inductance (inductive reactance). The unit measure of inductance is the henry. A coil has an inductance of one henry if an electromagnetic field (emf) of one volt is induced in the coil when the current is changing at the rate of one ampere per second. Were you to simply connect a constant DC current to an inductor only the series resistance of the wound coil would impact the current flow. An AC current is impacted by the inductor’s impedance.

An inductor is not the reciprocal of a capacitor.

RE: Elements of Electrical Engineering – Cook – Carr – 5th edition


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PostPosted: January 2nd, 2019, 7:52 pm 
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Walt,

Inductors do store energy in the form of EMF.

It takes time for the inductor to fully generate EMF irrespective of AC or DC source. After EMF is fully generated, inductor behaves like a plain wire with DC, not before.

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Last edited by Cogito on January 3rd, 2019, 10:19 am, edited 1 time in total.

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PostPosted: January 2nd, 2019, 8:01 pm 
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Energy is in fact stored in an inductor just like energy is stored in a capacitor. The mechanisms are different but both store energy. An inductor stores energy in the magnetic field created as current flows through the winding and a capacitor stores energy by building up charge on the plates.

Looking at two coils that are used in a crossover when not properly spaced, the field lines building up in one can efficiently cut across the windings of the other, inducing a voltage in the other coil that can cause problems.


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Energy in an Inductor.pdf [63.98 KiB]
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PostPosted: January 2nd, 2019, 8:12 pm 
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Cogito wrote:
Walt,

Inductors do store energy in the form of EMF.

It takes time for the inductor to fully generate EMF irrespective of AC or DC source. After EMF is fully generated, inductor behaves like a plain wire, not before.


It will act like a wire if you assume that there is some external limit to the current flowing through the inductor. If you had a perfect air core with no DC resistance and fed it with a constant DC voltage from a pure voltage source that could supply infinite current, the field in the coil and the current would continue to rise forever. Never happens in real life because of the limitations of "real" devices. The formula for the rate of change of the current is:

v=l di/dt where v=the applied voltage, l = inductance of the coil, and di/dt is the rate of change of the current. That formula also helps explain how the ignition coil in a car works. When you have a current flowing through the coil and you interrupt it very quickly the di/dt part of the equation becomes very large and therefore the voltage also gets very large and can arc across the spark plug.


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PostPosted: January 2nd, 2019, 11:39 pm 
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Joined: June 22nd, 2013, 11:00 am
Posts: 526
tomp wrote:
FerdinandII wrote:
tomp wrote:
The tabs are 1/4" "Faston" style spade lugs that I pulled off some old IBM equipment. They make a great way to connect the amp and drivers to the boards. I have lots if you need a few. I just drill a hole in the board and screw them down with a connecting lug under the screw. If you need to remove the boards for modifications you only have to lift the mating connectors off the lugs. You would need 1/4" female connectors to use with them and again there are tons of places on ebay that offer them at reasonable prices often with free shipping. Here is just one example of a connector with free shipping. They come in different sizes and with or without insulation. I keep a supply of male and female in different sizes both insulated and not on hand as they are always in use:

https://www.ebay.com/itm/100-Vinyl-Fema ... rk:26:pf:0


Or visit your local auto parts store. They will have a good selection in small quantities.


Probably cost more than the ones on ebay and also usually only come in assortments, most of which you will not use. I recently needed a replacement tire valve stem insert for one that was leaky on my car. The local Autozone had one for$3.50 plus tax and the time and gas to drive to the store and back. Ebay had a pack of 100 for $7.00 with no tax or shipping. I kept some and gave the rest to friends and family.


Who needs one hundred valve stems?

Yes, you save money. Or do you?

We should never ever compare items bought from one place with items from another place. Yes, they are the same type of item, but they are not the exact same item. The item itself could be inferior (cheap metal, cheap circuitry, cheap stitching, cheap design, etc.).

Everybody claims eBay as this great thing. eBay is no different than Craigslist. It is just an avenue to sell things. You are still dealing with individuals who may or may not be honest.

Yes, you can give them away. But, when you try to give away something to your buddies and they look the proverbial gift horse in the mouth, you feel like you don't want to give them anything else again.

I honestly feel that way about the those little blue-tooth speakers. Trying to be nice guy and ended up feeling like a loser.

I owe Cogito one at the very least. And, Brombo.


Last edited by mix4fix on January 3rd, 2019, 12:14 am, edited 1 time in total.

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PostPosted: January 2nd, 2019, 11:42 pm 
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tomp wrote:
Energy is in fact stored in an inductor just like energy is stored in a capacitor. The mechanisms are different but both store energy. An inductor stores energy in the magnetic field created as current flows through the winding and a capacitor stores energy by building up charge on the plates.

Looking at two coils that are used in a crossover when not properly spaced, the field lines building up in one can efficiently cut across the windings of the other, inducing a voltage in the other coil that can cause problems.


Frankly -- the term "stored" is misleading. The EMF is transient. However, I agree that once a magnetic field is established from a DC current there is a time constant before the interrupted field collapses. Air core, not so much, more so with an iron core or laminated steel core types.

A crossover network does not deal with DC current -- it deals strictly with the transient audio frequencies and the inductive reactance chosen to attenuate the signal at certain frequencies.

This dialog can give a layman a headache. So to get back to the real issue -- how to mount the coils -- if the coils are mounted parallel to each other the behavior is similar to a transformer. The coil with the dominant signal voltage/current can influence the less dominant coil. The effect on the sound quality is still questionable in terms of sensing a problem.

Better safe than sorry. Perpendicular mounting limits the possible interaction. But then why have the coils so damn close to each other in the first place?

My big issue with crossover design that seems to be ignored is the fact that series L/C and parallel L/C networks can resonate in a way that mimics mechanical resonances.

This was an issue that I was fighting 30 years ago until I looked at the L/C networks in terms of characteristic resonances (ringing). By applying damping resistors across the inductors and capacitors the sympathetic resonances were suppressed. Dave Wilson of Wilson audio tried that method at my insistence in the 1980s and found that the crossover ringing that was driving him mad stopped with the resistors. He had the instrumentation to actually "see" the results on a scope.

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