Best sub choice for XR8600D Mixer

[Cagey]

When I asked about a spray for the cone I wasn’t thinking paint. I was thinking a spray of a polymer of some kind that would be very dilute, be absorbed and remain flexible and yet would add some structural integrity to the paper. That may be my million dollar idea My experience with old speakers is that the paper “dries out” and oxidizes to the point where it eventually is weakened and it falls apart at the outside edges where all the movement occurs. That keeps the foam surround industry in business. Paper is just cellulose fibers bound together by lignins. With age the binder oxidizes and stops binding. The newer speaker is also a Pyle 15, so it is as close as I could find to the original Pyle 15. I think it will work fine for our group. The newer speaker does have the tacky black treatment on the outside edges like you see on many speakers. Maybe the old speaker could benefit from application of a similar polymer to the perimeter and will move more like the newer speaker.

Speakers are relatively cheap. I'd simply replace with new ones rather than change old ones hoping they will last longer by doing so. Maybe they will and maybe they won't, but if it were me I'd just use them until they fail.

A problem with adding paint or anything else to the cone is in doing an even application of it across the entire cone especially under the dust cap where the cone meets the voice coil bobbin. In order for this to be effective the entire cone must be included.

But I will say, since those are old speakers, experiment away! And report back the results please!

[Bartman]

The whole point of a piezo speaker is that it does bend with a force corresponding to the applied voltage.

Please SHOW me bent metal after use.

And I am saying it does NOT. The piezo or ceramic material applied to the metal disc merely excites it from an "internal mechanical strain" wikipedia describes it, but is not bending any metal.

By definition, it IS bending during use, which is how it produces sound. It's not very much, but it is there. If there was no bending at all, then there would be no sound. No one is claiming it stays bent after use, unless it got damaged by overheating or other.

Also, using wikipedia as a source, especially for anything technical, is not credible.

And the disc can't possibly follow the climbing applied signal, especially when that signal climbs to voltages the metal disc can't possibly move or vibrate enough to reproduce. Its rigidity is preventing it from following the signal.

Correct, the disk can't move (bend) much, and will distort the sound as the voltage applied to it exceeds its physical limitations.

As voltage climbs, due to the physical nature of their construction physics, their ability to continue to vibrate increasingly matching signal applied is impeded by the rigidity of the copper metal disc itself PREVENTING the driver from following climbing signal voltages. In fact, all of the materials used are hard solids and all of the parts of this driver physically resist vibrating by their very nature. The device is self defeating. It sounds worse and worse the louder the it gets.

And so, because of the driver's inability to vibrate physically more and more attempting to follow climbing signal, what is left that the driver can do ncreasingly turns into pure NOISE at higher levels rendering audio image resolution virtually null and void at that point.

The same is true for paper cone drivers with a voice coil. They too can only move so much, and increasing voltage on the coil results in turning it into noise, if the cone can survive being over extended or the coil bottoming out on the back of the magnet.

Piezo speakers are meant for the mom and pop circuit of people who don't care about quality sound and don't know any better and can be sold a $2.00 speaker as the best thing since sliced bread.

I agree they don't handle much power and sound quality is lacking, but they do have their place when high fidelity sound is not needed.

Speakers move air. Speakers push air. Piezos don't move air. They vibrate.

You contradict yourself again here. If something is vibrating in air, then it IS moving air. Again, it's not very much, but it is moving some. If there was no air movement, then there would be no sound whatsoever.

Oh, and piezos are not "limited in power" because they do not use any. They operate by voltage, not current producing heat or "power" as measured in watts. These worthless little discs are essentially a capacitor to the amplifier and nothing more. Volts excite them. Not watts. Piezos come with a voltage rating. If you exceed the voltage rating you can damage the device. But the disc is NOT dissipating power or heat measured in watts. The disc is NOT made for heat dissipation because it does not draw any current to produce any heat or power. It is a device excited by volts at super low current. So low the amp don't even see it really and you can hook up 10 of them and the amp still don't know it and you are NOT losing power from the other speakers either because the piezo does not draw any off.

You contradict yourself again here. You claim they don't use any power, then admit they do draw "super low current". A "capacitor to the amplifier" will draw current at high frequencies. Also, by definition, if there is mechanical motion (vibration) then work is being done, and if work is done by applying voltage, and current measured, even if only a small amount, this IS power. P=I*V

Loudspeakers: Voltage is converted to mechanical movement of a metallic diaphragm.

Voltage, not power.

You seem to not understand the definitions or application of these words when it comes to electronics. Power is a MEASUREMENT of that voltage being converted to mechanical movement (plus heat loss). There IS measurable power. If there was no power, then there would be no sound. If you could get sound without resulting in power, then you'd defy the laws of thermodynamics.

The reason you see power ratings along with piezos is because they are approximating what the voltage would be by referencing a standard of measure most people recognize and can follow. They are not saying the piezo can handle that much power because it will never see it.

Again, you are completely wrong here. They do consume power and rightfully have a power limit rating. You do not understand the basics of electricity, Ohm's law. My degree is in Electronics Engineering Technology and reading your repeated misunderstandings of how these things works is cringeworthy, especially when you come across so self-assured in what you think you know but don't.

I don't know how much clearer I can make it. Piezos are junk. What they produce is noise. (The color of it is irrelevant) Piezos should be avoided by anyone serious about sound.

An opinion, and I mostly agree, they do not sound good to me, they sound very harsh, but again, they do have their place.

[Cagey]

Some picky technical details.

When someone says something bends it bends and should show proof.

Now when the disc is excited, the piezo material is spread across the surface so it is the entire disc that is excited to vibrate. So its not technically bending. Its vibrating the whole disc across the surface as clearly seen in the images.

If the whole disc is vibrating back and forth, is the disc bending? I think you are wrong on that and your electrical engineering degree may need some mechanical engineering touch ups.

There is NO mechanical leveraging by the piezo material spread across the disc. It excites equally across surface. No bending. Entire disc moves as one as I see it. Now if you can prove that the disc is physically bending some how I would like to see proof of it.

I will continue to keep the opinion that the disc is NOT bending. I believe the whole disc is vibrating because the piezo material is spread out across nearly the entire surface of the metal disc, so no bending. The entire disc is vibrating and moving as one back and forth. Physically mount it may change how this is viewed.

As for pushing air I disagree. It does not push air same as woofer with voice coil. That piston moves air over a programmed distance. A disc is physically restrained. Its a disc. It vibrates. And yes, it excites air to sound waves, but is it pushing air in a way we can "fairly" cross compare to a woofer? Or just make a blanket statement that any sound comes from pushed air is what I am getting. I believe sound can be created in numerous ways and maybe its just me but I don't consider a volkswagon a ferrari and I don't consider a metal disc same as a woofer nor would I compare them in such a way.

When you rub two sticks together, is that pushing air also? Sound can be created without pushing. Vibrating and pushing as I see it are not the same. Again, we are getting in mechanical engineering which is outside of your degree and mine so I will leave it we agree to disagree.

I guess we need to get more picky on definitions because I too have read a bunch of total cringeworthy nonsense on here as well. And the general approach should be one of sharing and supporting one another and encouraging people to post and help others rather than target members with negativity.

Where are your corrective responses for:

"There is no "nasty sawtooth wave" without significant current draw from the power caps: they will top off just fine. "

"Just as one bit of info: letting a piezo tweeter run through the tweeter path of a frequency crossover intended for dynamic tweeters is a recipe for blowing them out because then the crossover and the tweeter may draw a lot of power at some frequencies due to pathologically low impedances."

"Peavey where the power transistors don't connect to the output rail but to the main amp ground and pull the power rails of the floating speaker power supply back and forth"

Oh and how about this one you did not come storming in to correct negatively as you did to me:

"Most crossover components don't lose a lot of heat, particularly not in comparison to speakers."

" (and the vast bulk of energy is not converted into heat but does not even leave the amp because it is blocked from getting to the woofer rather than getting wasted elsewhere)."

Where are the corrections? I'm not seeing it but this is what passes for top notch informative posts around here NO ONE challenges. Why is that?

Here, let me use a documented reference to correct what others unfairly won't:

https://www.xkitz.com/blogs/making-the- ... -passive-1

"Amplifier Power Wasted

Passive crossovers waste a huge amount of your amplifier’s power. In some cases up half of the available power from your amplifier is lost to heat dissipation in the crossover components.

The insertion loss of a passive crossover can be as high as 3dB. This means that to achieve a given Sound Pressure Level (SPL) in your sound system you need an amplifier with twice the wattage as would be necessary in a bi-amp system. The presence of the passive crossover in the speaker forces you to pay more for the amplifier than you would otherwise have to.

Active bi-amp systems have zero insertion loss and do not require twice the amplifier wattage to reach the same SPL level."

And on this forum you have people who say otherwise unchallenged.

If science and facts matter then show equal corrections across the board. In future I will be more careful with words and now less likely to offer help as freely.

[dak]

Just a few remarks (I don't quote the bulk with which I am in agreement):

The whole point of a piezo speaker is that it does bend with a force corresponding to the applied voltage.

Please SHOW me bent metal after use.

And I am saying it does NOT. The piezo or ceramic material applied to the metal disc merely excites it from an "internal mechanical strain" wikipedia describes it, but is not bending any metal.

By definition, it IS bending during use, which is how it produces sound. It's not very much, but it is there. If there was no bending at all, then there would be no sound. No one is claiming it stays bent after use, unless it got damaged by overheating or other.

Maybe "flex" would be a nicer word to use instead of "bend". To me, they are mostly synonymous but the former may have less implication of a permanent deformation.

Speakers move air. Speakers push air. Piezos don't move air. They vibrate.

You contradict yourself again here. If something is vibrating in air, then it IS moving air. Again, it's not very much, but it is moving some. If there was no air movement, then there would be no sound whatsoever.

Piezos are limited in excursion, so when they move fast, they have to change direction rather often. In other words, they are only useful as tweeters. Which is how they are being used.

Oh, and piezos are not "limited in power" because they do not use any. They operate by voltage, not current producing heat or "power" as measured in watts. These worthless little discs are essentially a capacitor to the amplifier and nothing more. Volts excite them. Not watts. Piezos come with a voltage rating. If you exceed the voltage rating you can damage the device. But the disc is NOT dissipating power or heat measured in watts. The disc is NOT made for heat dissipation because it does not draw any current to produce any heat or power. It is a device excited by volts at super low current. So low the amp don't even see it really and you can hook up 10 of them and the amp still don't know it and you are NOT losing power from the other speakers either because the piezo does not draw any off.

You contradict yourself again here. You claim they don't use any power, then admit they do draw "super low current". A "capacitor to the amplifier" will draw current at high frequencies. Also, by definition, if there is mechanical motion (vibration) then work is being done, and if work is done by applying voltage, and current measured, even if only a small amount, this IS power. P=I*V

Ok, this one is a bit more tricky: a capacitor will draw current at high frequency but won't consume net power: it just stores power from the amp and pumps it back at a comparatively bad moment for a typical push-pull amplifier (maximum current at the zero crossing of the output, when the full rail voltage is across the output transistors). So a capacitive load causes sizable power losses but those are burnt off as heat in the output transistors instead of the capacitors themselves. But a piezo speaker does not behave as a pure capacitor and converts a sizable fraction of energy not into an electric field but a mechanical displacement. In frequency ranges where it emits sound energy, the displacement and its return is significantly retarded by the mechanical resistance of the air accepting sound energy, and the return of energy is consequently incomplete. This measures as a lossy capacitor mostly at higher frequencies, whereas at low frequencies the losses are quite more modest.

The reason you see power ratings along with piezos is because they are approximating what the voltage would be by referencing a standard of measure most people recognize and can follow. They are not saying the piezo can handle that much power because it will never see it.

Again, you are completely wrong here. They do consume power and rightfully have a power limit rating. You do not understand the basics of electricity, Ohm's law. My degree is in Electronics Engineering Technology and reading your repeated misunderstandings of how these things works is cringeworthy, especially when you come across so self-assured in what you think you know but don't.

He is right is as far as tweeter ratings in general are not in line with the power the tweeter itself consumes but in line with the fraction of pink noise power that would actually get to the tweeter. A 50W tweeter does not survive a 4kHz 50W signal. Also coil tweeters have their sensitivity and power rating referenced to their own nominal impedance while piezo tweeters are typically referenced with regard to being connected in parallel to an 8ohms woofer. Simply because referencing their actual power levels and sensitivities would make it harder to put them into context as they have significant impedance variation over their frequency range and surprisingly large efficiency.

[Cagey]

The reason you see power ratings along with piezos is because they are approximating what the voltage would be by referencing a standard of measure most people recognize and can follow. They are not saying the piezo can handle that much power because it will never see it.

Again, you are completely wrong here. They do consume power and rightfully have a power limit rating. You do not understand the basics of electricity, Ohm's law. My degree is in Electronics Engineering Technology and reading your repeated misunderstandings of how these things works is cringeworthy, especially when you come across so self-assured in what you think you know but don't.
[/quote]
He is right is as far as tweeter ratings in general are not in line with the power the tweeter itself consumes but in line with the fraction of pink noise power that would actually get to the tweeter. A 50W tweeter does not survive a 4kHz 50W signal. Also coil tweeters have their sensitivity and power rating referenced to their own nominal impedance while piezo tweeters are typically referenced with regard to being connected in parallel to an 8ohms woofer. Simply because referencing their actual power levels and sensitivities would make it harder to put them into context as they have significant impedance variation over their frequency range and surprisingly large efficiency.
[/quote]

I'm glad you caught that. And that you have a sense of fairness. I appreciate it very much.

[dak]

Where are your corrective responses for:
...

Ok, here is the deal. It turns out that I am not just a rather seasoned dabbler in electronics and circuit design who started as a hobbyist in his youth but I am also a graduated electrical engineer with a specialisation in signal processing. I stand by everything I wrote and what you quoted here.

However, there is little point in a point by point refutation particularly by myself because if you are convinced that all that is a bunch of nonsense that I am putting out through whatever bodily opening, a more elaborate accumulation of such nonsense worded in a similar manner will just make you fume off in anger.

I suggest that you pick out one of those statements you find issue with and then we'll see whether I can put a solid enough backing behind it for you to see the point I am making. Focusing on a single point may also make it easier to see for me where I need to provide more theory in what manner to make my point accessible to someone approaching the matter from a different background.

That is better done one by one than in a large humongous controversial blob not getting into sufficient depth.

[Dookie]

I've seen a lot of post here. Some informative, some not. Some taken way out of context or with facts that seem important or plausible when they are stated but, in a way, really don't matter at all. I'd like to give some down to earth examples that may give a reader a different point of view. I've seen passive crossovers with their insertion losses stated a lot here. I'd like to cover this.

When a person purchases a speaker system, they are doing exactly that. Purchasing a speaker system as a whole. Some basic purchase guidelines, in the order that a person feels is important, might be, cost, speaker output, sound quality, and system setup as a starting point.
So, for this example I want 2 speakers that put out 130dbs of spl at a given coverage angle, I want them to sound ok and my budget is $1500.
For $1500 I can get 2 Self Powered speakers that fit this requirement.
Also, for $1500 I can get 2 passive speakers and a power amp with internal equalizer presets that sound exactly the same as the active ones. I've shopped around and found I can do this.
So first I feel that the active speakers are the way to go because I won't have to lug around a power amp that takes up space on the stage. Then thinking about it I don't want to bother with plugging both a mic cable and a power cable into a speaker for my setup, so the passive speaker/amp is for me. What is not considered in this purchase is what the insertion loss is of the crossover in the passive speaker. It doesn't matter. What truly matters is the system as a whole and how it fulfills the requirements I need when I spend my money.
Passive speakers and active speakers are different, and person can't compare the two as the components inside are different so different results are given for each speaker type. What matters is how different speakers as a whole are compared and what the person who purchased them wants. Budget might be a big factor. Or weight, or sound quality. It goes on and on.

Now with the above said I'd like to address insertion loss of a passive crossover. There is NO SET NUMBER as to what the insertion loss could be. It could be 1 db in a basic crossover or 10db or in a complex crossover. This insertion loss only matters in relation to the speaker system as a whole and what it does when that system is compared to another to fulfill a system requirement.

That said the person who banged the drum on insertion loss is "exactly correct" as to the fact that insertion loss is very important to consider and does happen. This would be most important when "designing a speaker system". If I had a horn and woofer and was building a speaker system and, in this example, I could purchase 2 passive crossovers that yielded the same results, and one would give me 3 dB's of insertion loss for $30 while the other would give me 6 dB's of insertion loss for $15 dollars I would then pick the best passive crossovers to finish the speaker in relation to the cost/benefit of the crossover insertion loss in the speaker system as a whole. When comparing "different passive crossovers", insertion loss has to be considered and is very important to the final spl of a speaker system when being manufactured. The poster who is talking about insertion loss again is correct and seems to have a wealth of knowledge, but we need to see this added into the speaker system purchase as a whole not as a determining factor.

To conclude when purchasing a speaker, we are doing exactly that, purchasing a whole speaker. We have to look and compare each speaker on cost, sound quality (when pushed or not), output, coverage angles, weight, appearance, mounting possibilities, on and on and determine what is best for us. What is "inside" a speaker to give you those requirements is done in the manufacturer's plant. You look at the speaker system after it has been built and determine what is best for you. I'm not sure but you may be able to get an electric car and a gas car that give the exact same performance you need but inside they are completely different. The two as far as what is used to get the given performance are a completed, manufactured product. So now all you can do is compare which type of car is best as a total package to take you down the road.

Just some down to earth things to think about.
Doug

[Cagey]

Now with the above said I'd like to address insertion loss of a passive crossover. There is NO SET NUMBER as to what the insertion loss could be. It could be 1 db in a basic crossover or 10db or in a complex crossover. This insertion loss only matters in relation to the speaker system as a whole and what it does when that system is compared to another to fulfill a system requirement.

That said the person who banged the drum on insertion loss is "exactly correct" as to the fact that insertion loss is very important to consider and does happen. This would be most important when "designing a speaker system".

I'd like to add that this thread started with photos of a crossover that now looks like this:



My main point about insertion loss is that there is a line of performance demands or requirements as noted above. This crossover represents that line. There is low level on the safe side of this crossover, and there is high level beyond what this crossover can handle or achieve.

It appears the smoked crossover shows that more was asked of it than it could deliver. Possibly over powered. So the crossover gave way.

My point was it was that it was possibly the insertion loss or, the loss of power as heat in that crossover that led to such damage was possibly behind it. In other words more power delivered to it than it could dissipate without damage hence the burning.

So yes it is important to consider when designing speaker systems, but is this a case of when a crossover is preventing the speaker system from reaching desired higher levels because the crossover simply is not up to the task? And this is maybe when a change to get to higher power levels and higher SPL's can be made.

I already mentioned how the Lynyrd Skynyrd band and others switched out the LFD with high end guitar speakers and ran them direct voice coil to amplifier so ***almost 100% power delivered to LFD- with a little sent off to HFD. And, the HFD's were crossed over of course, but also fed into 100 watt 8 ohm L-pads to further protect the HFD voice coils from damage. One can also shift the HFD crossover frequency point higher and increase the slope roll off so one can send even more power to it if the LFD can handle it.

I would also change out those 1/4" jacks to speakon's because the 1/4" jacks simply are not good current carrying connectors. I generally use guitar amps as the cut off line. Anything above guitar amps and change them. And those average 100 to 180 watts tops. Honestly I don't want to use 1/4" jacks for anything over 100 myself. But to each their own.

Now much higher SPL's can be achieved while dialing in on necessary frequencies by specific choice of guitar speakers which help vocals and other to cut through stage volume out of those monitors better. Works great and has been done for decades. I still do it too. Toss out the foam and rubber surround bottom end speakers with long throws and throw in some short throw JBL E120's (my favorites) or EV 12L's like Electro Voice did to their production model speakers both mains and monitors had guitar speakers in them right out of the factory. If it works, it works. I'm using 4 12L's now in front left and right home theater. Talk about reaching some high SPL's. And clean too. Loud, powerful, and clean. Rip your head off volume. When space aliens invade earth in movies those soundtracks explode the war into the living room. Love it! No worries of blowing anything except the circuit breakers.

Simple changes can blow past the burned up crossover while at same time getting rid of that which is robbing the power and causing the failure. Now all you gotta do is tame the EQ curve you want and fire away. Pure power to the ears and not things to burn up when you need it most.

So to me the insertion loss of a crossover is not only important as you said, but also in consideration of if it is actually in the way and preventing one from getting to where they need to go without failures like that or even having one around to possibly fail like that. I prefer power to the speakers. The less highway robbers to mess things up the better.

When I see a burned up crossover like that I have to consider if the user needs to go to where this one can't. Just change or modify it to make it so it can. Captain Picard would say "make it so!"

Top of the line guitar speakers run direct, and taking their frequency curve into account, and one can play with where they want the HFD crossover point to be, and the guitar speakers curve on upper end give one the ability to raise this HFD crossover point which can allow the overall speaker to handle more power without damaging the HFD. And by using an L-pad can further protect the HFD and bring more control and balance to the speaker system since usually high compression HFD's are generally more efficient and sensitive than LFD's so the L-pads really help out a lot in two ways.

Now the only thing holding a monitor like that back is LFD power ratings and possibly 1/4" connectors. How powerful is the guitar speaker installed? Hundreds of watts. Well beyond what the smoked crossover can handle. During a performance, the crew and artists- and audience- do not have to worry about puffs of smoke out of the monitors in the middle of a song.


----------------------

I added the word almost to appease the infallible.

[dak]

I'd like to add that this thread started with photos of a crossover that now looks like this:



My main point about insertion loss

Well, I think that this "crossover" is not really par for the course. It looks like significantly home-brewn. It doesn't even all look like a crossover: the part on top looks like a bridge rectifier feeding into a relay through some burnt resistor (and since any actual resistors in a crossover tends to be used for burning off significant energy, and even to some degree when used in series with a piezo tweeter, it looks awfully small). I may be misidentifying some components here, but the point is that the components are highly unusual. This just is not representative for a standard crossover.

[Cagey]

This just is not representative for a standard crossover.

Not representative of a standard professional grade crossover. You're right.

Its Cerwin Vega.

'Nuff said.

[dak]

This just is not representative for a standard crossover.

Not representative of a standard professional grade crossover. You're right.

Its Cerwin Vega.

'Nuff said.

It isn't standard, is it? So statements about standard crossover use don't apply, do they?

[Bartman]

He is right is as far as tweeter ratings in general are not in line with the power the tweeter itself consumes but in line with the fraction of pink noise power that would actually get to the tweeter. A 50W tweeter does not survive a 4kHz 50W signal. Also coil tweeters have their sensitivity and power rating referenced to their own nominal impedance while piezo tweeters are typically referenced with regard to being connected in parallel to an 8ohms woofer. Simply because referencing their actual power levels and sensitivities would make it harder to put them into context as they have significant impedance variation over their frequency range and surprisingly large efficiency.

I haven't claimed that a piezo would survive a straight 4kHz signal at whatever voltage it takes to consume 50W of power, because as you said, they too are frequency dependent in their impedance, hence why piezo as well as coil tweeters and woofers all have nominal ratings just to give you a ballpark figure. To get the absolute power handling ability, you would have to test with a frequency sweep and measure it out on a graph, and even then, there is some degree of subjectivity since you would have to decide how much distortion in sound and heat and/or deformation of the components is acceptable before you say "here's the limit". I agree the power consumed is a small fraction compared to other components in the system, but my main point is that there is some power actually consumed by the piezo element since it is producing sound (changing electrical energy into mechanical energy). Cagey was claiming that there was zero power consumed, which is physically impossible.

[Cagey]

JBL does not use glue to hold it all together. And look at the options available and connectors, etc. Overall construction and design show professionalism at a much higher level, while the burned crossover glued together is one I would view as not professional.

Cerwin Vega is not known for concert sound systems and high level drivers. They made their fame and name in the living rooms across America as the home speaker company with pink foam surrounds that always dry rotted out faster than everyone else's.

Cerwin Vega is not a brand I would choose for the stage is my point.

I'd reconstruct the cabinets away from that brand and do it like I mentioned earlier and why.

The one thing about those old Cerwin Vega monitors I do really like are the metal connector plates and metal handles. Those are priceless these days and I would repurpose those- remove 1/4" connectors and drill them out and install speakons in them. If enough room maybe parallel with some 1/4's for versatility. I have a newer Marshall 4-way that could benefit from those. Those metal handles would fit right in place of the cheap chinese plastic in there now.

JBL is also using real power resistors different than what burned up on the one shown in this thread. And you also don't see electrolytics included in JBL or EV crossovers like you do with this one. Worlds of difference between professional and....





Electro Voice monitor connectors and crossovers are also worlds different than Cerwin Vega. No comparison really in construction quality and performance quality as well.



And then... I'm curious if Cerwin Vega actually published a spec sheet on this monitor model- I ask with a measured dose of sarcasm. So yes you are absolutely correct. This is no standard crossover.

I'd love to have those metal connector plates though... and metal handles. Hold on to those! Really nice vintage quality there. There is enough room to add speakons it looks like and possibly a stereo/mono switch as well. I'd scrape off the glue and that mess its holding on there and get some new life out of those connector plates and send some real power through them- without puffs of smoke when this glued "crossover" goes POOF!

[Cagey]

the part on top looks like a bridge rectifier feeding into a relay through some burnt resistor.......... I may be misidentifying some components here, but the point is that the components are highly unusual.

I think you are on to something.

I started looking at it closer and I think you are right. It does look like a small bridge rectifier don't it? And it looks like its sitting on top of a small relay.

Could it be an SCR? Something that would fire if a voltage is exceeded or if the signal goes DC? And the relay fires switching the voice coil or coils out of harm's way?

My vote is for some kind of interesting looking speaker protection device added to a simple crossover appearing to be part 6dB and part 12dB with inadequate resistive attenuation.

Could it be an auto-resetting relay?

Its in a plastic housing. Has 4 pin configuration. The other images don't show it any better. Appears to have some writing on side. I see the snaps on sides holding innerds in place. Looks like a small relay of some sort probably used as some speaker protection device in combo with what is on top. Interesting. Simple but it might save some coils. Buy them some time- out of warranty.

[Dookie]

Now with the above said I'd like to address insertion loss of a passive crossover. There is NO SET NUMBER as to what the insertion loss could be. It could be 1 db in a basic crossover or 10db or in a complex crossover. This insertion loss only matters in relation to the speaker system as a whole and what it does when that system is compared to another to fulfill a system requirement.

That said the person who banged the drum on insertion loss is "exactly correct" as to the fact that insertion loss is very important to consider and does happen. This would be most important when "designing a speaker system".

I'd like to add that this thread started with photos of a crossover that now looks like this:



My main point about insertion loss is that there is a line of performance demands or requirements as noted above. This crossover represents that line. There is low level on the safe side of this crossover, and there is high level beyond what this crossover can handle or achieve.

It appears the smoked crossover shows that more was asked of it than it could deliver. Possibly over powered. So the crossover gave way.

My point was it was that it was possibly the insertion loss or, the loss of power as heat in that crossover that led to such damage was possibly behind it. In other words more power delivered to it than it could dissipate without damage hence the burning.

So yes it is important to consider when designing speaker systems, but is this a case of when a crossover is preventing the speaker system from reaching desired higher levels because the crossover simply is not up to the task? And this is maybe when a change to get to higher power levels and higher SPL's can be made.

I already mentioned how the Lynyrd Skynyrd band and others switched out the LFD with high end guitar speakers and ran them direct voice coil to amplifier so ***almost 100% power delivered to LFD- with a little sent off to HFD. And, the HFD's were crossed over of course, but also fed into 100 watt 8 ohm L-pads to further protect the HFD voice coils from damage. One can also shift the HFD crossover frequency point higher and increase the slope roll off so one can send even more power to it if the LFD can handle it.

I would also change out those 1/4" jacks to speakon's because the 1/4" jacks simply are not good current carrying connectors. I generally use guitar amps as the cut off line. Anything above guitar amps and change them. And those average 100 to 180 watts tops. Honestly I don't want to use 1/4" jacks for anything over 100 myself. But to each their own.

Now much higher SPL's can be achieved while dialing in on necessary frequencies by specific choice of guitar speakers which help vocals and other to cut through stage volume out of those monitors better. Works great and has been done for decades. I still do it too. Toss out the foam and rubber surround bottom end speakers with long throws and throw in some short throw JBL E120's (my favorites) or EV 12L's like Electro Voice did to their production model speakers both mains and monitors had guitar speakers in them right out of the factory. If it works, it works. I'm using 4 12L's now in front left and right home theater. Talk about reaching some high SPL's. And clean too. Loud, powerful, and clean. Rip your head off volume. When space aliens invade earth in movies those soundtracks explode the war into the living room. Love it! No worries of blowing anything except the circuit breakers.

Simple changes can blow past the burned up crossover while at same time getting rid of that which is robbing the power and causing the failure. Now all you gotta do is tame the EQ curve you want and fire away. Pure power to the ears and not things to burn up when you need it most.

So to me the insertion loss of a crossover is not only important as you said, but also in consideration of if it is actually in the way and preventing one from getting to where they need to go without failures like that or even having one around to possibly fail like that. I prefer power to the speakers. The less highway robbers to mess things up the better.

When I see a burned up crossover like that I have to consider if the user needs to go to where this one can't. Just change or modify it to make it so it can. Captain Picard would say "make it so!"

Top of the line guitar speakers run direct, and taking their frequency curve into account, and one can play with where they want the HFD crossover point to be, and the guitar speakers curve on upper end give one the ability to raise this HFD crossover point which can allow the overall speaker to handle more power without damaging the HFD. And by using an L-pad can further protect the HFD and bring more control and balance to the speaker system since usually high compression HFD's are generally more efficient and sensitive than LFD's so the L-pads really help out a lot in two ways.

Now the only thing holding a monitor like that back is LFD power ratings and possibly 1/4" connectors. How powerful is the guitar speaker installed? Hundreds of watts. Well beyond what the smoked crossover can handle. During a performance, the crew and artists- and audience- do not have to worry about puffs of smoke out of the monitors in the middle of a song.



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I added the word almost to appease the infallible.

When it comes to a speaker system, even the one shown above with the burnt crossover, the real issue is not the passive crossover, not the horn or woofer but the operator who was feeding this speaker pushed it too hard and burned it out. The passive crossover and the speakers in it would only give X-amount of output. When the person purchased this speaker, they didn't purchase the correct speaker with enough output, then pushed too hard so it failed. They didn't do what a competent intelligent engineer would do and work within the limits of the speaker. Instead, they pushed beyond the speaker's available power handling. That had NOTHING to do with the passive crossover in the box. Maybe someone has had a few beers and smoked a few and thought they knew what they were doing? I've seen more than a few of those out there. So now some of the speaker components are fried so I just put a straight shot to woofer and eq the heck out of it and it is 3dbs louder. Is 3dbs now the magic number? Can you guarantee to me that there even is 3dbs of spl loss in this crossover shown above? Because it seems the operator who damaged these speakers didn't know what they are doing what is to stop them from pushing the woofer too hard and frying the woofer coil? If these new speakers that you put in the monitors in your example can handle the wattage what did these replacement woofers cost money wise? Why wasn't the money put into the first speakers' budget to start with so the right speaker for the job was available and wouldn't fail? If the speakers were properly spec'd and the operator had a clue, then the speaker never would have failed at the start.

If you are running a monitor system and you push too hard and burn the speaker up that means you didn't spec the speaker correctly and you, as the operator, are responsible for the failure not the speaker. If you take the speaker and modify it to get by that doesn't mean that what was done is correct or that it is the standard. It means that you are trying to cover for your mistakes or just getting by with what you have on hand. If band X wants just woofers in their monitors, then that is just part of their rider. That has nothing to do with the fact that you burned out a speaker system because you didn't properly operate it. I'm guessing although this may have been ok in years passed and possibly with a few B and C level bands today in a pinch, it is few and far between. A passive or an active speaker can all be fried if the operator lacks the basic skills to operate a sound system. Speakers can fail because they wear out make no mistake about it but when one is driven into the ground and fails then it is a clear sign that a "sound engineer" really isn't an engineer at all.

I spent over 10 years on my day job working with people who have developmental disabilities (diagnosed with MR or Mental Retardation) and before that worked with people with drug and alcohol addiction. There would be times when a person who had alcohol or drug addiction would have a car accident. They would say it was foggy out and couldn't see so that is why they drove into a tree. Or it was raining, or snowing etc. They would never say they were fall down drunk or shooting up and impaired. Their addictions were never part of the problem. It was always something else. A guy would beat his wife close to death, but it was her fault because she just wouldn't listen to him, and she made him mad. It's all her fault.

When I see a burnt speaker and someone (not you of course) blames the speaker and the components inside I hear that same deflection on responsibly. It was the crossovers' fault. It was the woofer's fault. The amp clipped so damaged the speaker. On and on. At some point though a person has to become an adult and face reality. Put the fault squarely where it belongs. Maybe I've been lucky, maybe I just made sure I did my job correctly but to date haven't smoked a woofer, crossover, or horn. Pretty good for a little over 34 year When band X hires me to do a job, I bring what is needed within the budget. If the budget isn't enough, I contact the band and tell them why. If they want to increase the budget and get what is needed, I bring more and if I don't have enough gear then possible cross rent to make it happen. If the band doesn't have the budget, then I'll let them know ahead of time that the system I can provide is subpar and give them the choice of looking elsewhere for a different sound provider or if they want to stay with me just know I'll do the best I can within the SPL the speakers can provide. If my system is budgeted and is too small and I run it into the ground and burn it up to "rock and roll" while smoking something that doesn't smell like a cigarette and drinking some beers, then it is 100 percent my fault. In no way shape or form is it the speakers. I would put the blame squarely on me. Any competent educated engineer would do the same.

*Disclosure* I'm a kidney donor so although I could drink, I feel for me it is wise not to. I've never smoked.

I truly believe you have a high knowledge of many aspects of speakers and the design of them. But with all this knowledge what are you doing burning all these speakers up and why are the components being blamed when the damage is squarely on your shoulders? Knowledge and common sense need to be used together. If a person knows what it takes to make a speaker fail, then why would they let it happen? Saying the artist wants it loud is an excuse just like saying it was raining and I couldn't see, or she made me mad. If an artist screams at you and makes you turn up too much and you burn a speaker, then it is your fault and that is how it goes. Put the blame on yourself where it truly is, fix the speaker and move on. For me I will never put the blame where it doesn't belong as far as speaker failure. No matter how many excuses are used ""'Speakers don't blow themselves up""". Poor operators, who lack proper sound system operational knowledge or how to spec a system properly to do a job do. You with all your knowledge should know this.

You can't teach common sense, regardless of how intelligent a person your trying to teach may be. A person has it or they don't.

Doug