KP-302/3002 High Frequency Speaker - Intermittent & Scratchy Sound - Resolved, Bad Cap' Connection

[Edgar]

4 hours ago, Travis In Austin said:

I thought we were not supposed to call them crossovers? Or is that just dumbed down vernacular? 

 

Please don't tell me that "crossover" has somehow become politically incorrect.

 

"Dividing Network"? "Subband Filter"? "Frequency-Selective Object"? "Passband Particulator"? "Bandwidth Beautifier"? "Tonal Attenuator"?

[Edgar]

4 hours ago, Travis In Austin said:

"Three engineers go into a bar  . . . ."

 

Have you heard the one that starts, "A doctor, a lawyer, and an engineer face the Guillotine."? 

[Travis In Austin]

57 minutes ago, Edgar said:

 

Please don't tell me that "crossover" has somehow become politically incorrect.

 

"Dividing Network"? "Subband Filter"? "Frequency-Selective Object"? "Passband Particulator"? "Bandwidth Beautifier"? "Tonal Attenuator"?

No not at all.

 

At the class in 2019 when I popped in to check on the group over at the lab Roy was talking about poles, etc. and I asked a question about "crossovers" and a few people said "they are not  crossovers" which I assumed meant that Roy at some point in the class said the proper word was a "network" or "balancing network" (not sure which???). I think I was corrected again even when I corrected myself and said "crossover network", I can't remember what the more precise term was. It was in reference to either the AL5 or AK6. 

 

This would make sense as PWK was typically very precise in his writing and words, especially in peer reviewed context to use terminology that the "network" was resulting in a crossover point at a frequency. I can't recall what phraseology PWK used in more informal writings like the Dope From Hope. 

 

Obviously, in the context of conversations here "crossover" is a convenient way to discuss the wood block thing with the yellow cylindrical objects and transformer looking thing on top. There is obviously numerous threads that start out that way. 

 

Obviously PWK would have set the correct nomenclature that Roy would have adopted. I have seen plenty of video of PWK gently correcting someone using an incorrect term. Maybe Paul picked that up from the technical writing of the day, or from patent application wording.  Maybe the style manual at AES is what sets the tone for this. OR, it could be the Roy writing specs and descriptions for the the marketing guys, they send him a draft and it uses the term "crossover" for the device that creates the crossover frequency, he draws a line through it and sends it back with the words "passive network" or "balancing network." 

[Travis In Austin]

Not sure now what the correct phrase was in order to precise: Crossover Filter Network. I remember something else that was mentioned that a "balancing network" also had a very precise and distinct meaning. Maybe it attenuated output of of one or more of the drivers in addition to rolling off the frequencies at various points? Or maybe it means the filter network also has EQ in it?

 

 

 

[ClaudeJ1]

5 hours ago, Travis In Austin said:

 I never asked him how much he was able to narrow Paul's fudge factor

Thanks for the post, Travis. Not having had that conversation with Roy, I still figured he would have done the same thing. We all have to have our own "fudge factors" when designing speakers. It's a lot harder to do a horn than a direct radiator because of so many more variables besides the drivers and crossovers. Modern simulation tools are still helpful to get us all in the "ballpark" to a very close degree. But we still have to do the "measure/listen/tweak" routine to "close the loop" so to speak. Mother nature seldom reveals her secrets easily. This is why entire careers are focused on tiny slices of Application of those secrets, once revealed and UTILIZED!

[Travis In Austin]

1 minute ago, ClaudeJ1 said:

Thanks for the post, Travis. Not having had that conversation with Roy, I still figured he would have done the same thing. We all have to have our own "fudge factors" when designing speakers. It's a lot harder to do a horn than a direct radiator because of so many more variables besides the drivers and crossovers. Modern simulation tools are still helpful to get us all in the "ballpark" to a very close degree. But we still have to do the "measure/listen/tweak" routine to "close the loop" so to speak. Mother nature seldom reveals her secrets easily. This is why entire careers are focused on tiny slices of Application of those secrets, once revealed and UTILIZED!

Were you in the recent thread here where someone was commenting about (I think it was) Roy's patented vented LF (1802) and they were commenting that they were using some sort of modeling or simulation software (if might have been the new Celestion driver) and there wasn't a correlation? It was a well accepted program, but useless when it came to what was trying to be sorted out. 

 

 

[Edgar]

23 minutes ago, Travis In Austin said:

At the class in 2019 when I popped in to check on the group over at the lab Roy was talking about poles, etc. and I asked a question about "crossovers" and a few people said "they are not  crossovers" which I assumed meant that Roy at some point in the class said the proper word was a "network" or "balancing network" (not sure which???). I think I was corrected again even when I corrected myself and said "crossover network", I can't remember what the more precise term was.

 

I had a friend who was blind. People would refer to him as "sightless", or "visually impaired", or "visually handicapped". He would correct them:

 

"I'm blind, d**n it!"

 

Sometimes the simplest description is the best.

[ClaudeJ1]

24 minutes ago, Travis In Austin said:

Were you in the recent thread here where someone was commenting about (I think it was) Roy's patented vented LF (1802) and they were commenting that they were using some sort of modeling or simulation software (if might have been the new Celestion driver) and there wasn't a correlation? It was a well accepted program, but useless when it came to what was trying to be sorted out. 

 

 

I don't think I was, no. But if you'll give me a link, I can go have a peek.

[captainbeefheart]

2 hours ago, Travis In Austin said:

Not sure now what the correct phrase was in order to precise: Crossover Filter Network. I remember something else that was mentioned that a "balancing network" also had a very precise and distinct meaning. Maybe it attenuated output of of one or more of the drivers in addition to rolling off the frequencies at various points? Or maybe it means the filter network also has EQ in it?

 

Multiplexer ?

 

Basically taking information and splitting the output ports by frequency

[Travis In Austin]

3 minutes ago, captainbeefheart said:

 

Multiplexer ?

 

Basically taking information and splitting the output ports by frequency

You got me. I'm just an old country lawyer, son of a "Magnetic Tape Engineer" (it's on my birth certificate) so grew up around audio. He could take stuff apart and make it better, me, I could take it apart really, really well, but not so much after that. 

 

P.S. I really like your posts on things like wire gauge for a run length of cable, caps and a whole host of other things. 

[captainbeefheart]

6 minutes ago, Travis In Austin said:

P.S. I really like your posts on things like wire gauge for a run length of cable, caps and a whole host of other things. 

 

Thank you! I try and bring some sanity to some of the more subjective topics in audio like capacitors and cables, which honestly are fairly objective when getting down to the details.

 

 

Always good to know a lawyer

[Travis In Austin]

2 hours ago, Edgar said:

 

I had a friend who was blind. People would refer to him as "sightless", or "visually impaired", or "visually handicapped". He would correct them:

 

"I'm blind, d**n it!"

 

Sometimes the simplest description is the best.

In every Dope From Hope PWK referred to it as a "crossover network" never, ever a "crossover." So I think I know where Roy get's that from. I suspect that Roy would say "crossover" in a conversation with PWK, Paul would say, Sr. Delgado, it's a crossover network, the word "crossover" by itself is descriptive of nothing. For example, crossover band, crossover frequency and when you say "crossover" I don't know to what you are referring to in order to answer your question." Roy would leave the office and say "I do that every time." After 3 such encounters and having to give a speech at Rotary about it, it was forever a "crossover network." 

 

The only exception was a reference to an "electronic crossover" starting in 1972. So I suspect someone else dubbed it as such and he was stuck with the term and put it in quotes to show he would have never named something so imprecisely.  

 

All of this, by the way, isn't a comment on anyone else or their prior posts, it's a comment to myself that I can't even properly describe the (circuit, device, contraption, thingamajig?) that does what it needs to do to have good sound. 

 

The one reference I was able to find Re: a "balancing network" was a 1950s (late) brochure, so it can't be attributed to PWK directly, but probably has a higher chance that he wrote it, or approved. It was in reference to the "H Model" which said it was available with a "balanced crossover" in two configurations, one for use as a primary speaker, or one for use as a center stereo speaker.

 

 

[Edgar]

6 minutes ago, Travis In Austin said:

In every Dope From Hope PWK referred to it as a "crossover network" never, ever a "crossover."

 

I concede. 🙂

[Travis In Austin]

5 minutes ago, Edgar said:

 

I concede. 🙂

I'm still going to call it a "crossover." It's one of those things you can say in a conversation of audio nuts to fake your way in: Hey Roy, what were the changes in the crossover? Where do you have the woofer/squawker (bonus points for squawker) crossing over at?

 

To which Roy will answer, at UT we never finished our sentences with a preposition, sir. Okay, where do you have them crossing over at . . . Bonehead. Then you move to the back of the room when you, Mark, JC, start asking, did you decide 580 instead of 500 because of [and then you guys rattle off the pros and cons of a particular crossover frequency due to phase, it's a natural point because of FR of musical instruments, or a dozen other things.

 

I just want to know one thing, why is that fact that "no sound in nature has constant phase" relevant/important to crossovers, whether passive, or active with FIR phase correction? Can you put too much phase correction in?

[billybob]

Filter is a word that some are using now.

[CWelsh]

8 minutes ago, Travis In Austin said:

I just want to know one thing, why is that fact that "no sound in nature has constant phase" relevant/important to crossovers, whether passive, or active with FIR phase correction? Can you put too much phase correction in?

 I'm curious about this, too. When the phrase came up earlier in the thread I started thinking about descriptions such as "sound stage depth" "air" and other terms that are used with reference to how we get to a "live" sound. Does the phase coherence of the speakers affect whether or not I can hear the virtual location of one cymbal relative to another in that sound stage? Or, is there something else that creates the image?

 

[Edgar]

The audibility of phase distortion is the subject of much debate, argument, insult, and fisticuff. There are many good-sounding loudspeakers that are not phase-coherent. There are many phase-coherent loudspeakers that do not sound good. Inside a room, where reflections abound, the whole idea of phase coherence may be moot. [*]

 

[*] @Chris A would quickly point out that broadband controlled-directivity loudspeakers will largely eliminate the problems caused by reflections.

[ClaudeJ1]

2 hours ago, Travis In Austin said:

In every Dope From Hope PWK referred to it as a "crossover network" never, ever a "crossover." So I think I know where Roy get's that from

From a functional point of view, it should be called a "balancing network," but technically it's a "Blocking Network" because by strict definition of actual FUNCTION, it's really a BLOCKING Network. Nothing ever "Crosses Over" but select frequencies in the signal are strictly BLOCKED (gradually of course).

[captainbeefheart]

3 hours ago, Travis In Austin said:

I just want to know one thing, why is that fact that "no sound in nature has constant phase" relevant/important to crossovers, whether passive, or active with FIR phase correction? Can you put too much phase correction in?

 

Phase is mostly relevant when two or more drivers are overlapped (at the crossover frequencies) and sum as the total acoustic output from each driver. This is most important during transients with fast rise times like a square wave, if each contributing driver is reaching it's peak at different times from phase lag in the networks then the wave forms will reach your ears at different times. My guess is these peaks reaching the ear at different times creates an apparent Doppler like frequency shift similar to vibrato effects. It may also have a similar delay effect, short delays are called chorus effects where it sounds full and pleasing  similar to the vibrato.  Probably explains why people have heard awful time aligned speakers and like the sounds of them. Sometimes technically perfect things aren't always best, or are they?

[captainbeefheart]

2 hours ago, ClaudeJ1 said:

From a functional point of view, it should be called a "balancing network," but technically it's a "Blocking Network" because by strict definition of actual FUNCTION, it's really a BLOCKING Network. Nothing ever "Crosses Over" but select frequencies in the signal are strictly BLOCKED (gradually of course).

 

Look at the frequency response on a Bode plot of all the outputs summed and you will see the stop band section of each filter crosses over one another at the "crossover" frequency. I believe this is where the name came from.

 

The stop band section of the high pass filter network will crossover into the stop band section of the low pass filter network.