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

[Edgar]

22 minutes ago, captainbeefheart said:

My guess is these peaks reaching the ear at different times creates a 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. 

 

Research into temporal masking tends to refute this concept. Separated by less than a certain threshold, the disparate arrival times cannot be discerned at all. That threshold is in tens or hundreds of milliseconds. https://www.sciencedirect.com/topics/medicine-and-dentistry/temporal-masking

[Edgar]

26 minutes ago, captainbeefheart said:

 

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.

 

That is essentially as it was explained to me. The signal "crosses over" from one driver to the next as the frequency changes.

[Deang]

9 hours 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"?

Just “filter” works pretty good. 

[Edgar]

26 minutes ago, captainbeefheart said:

 

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.

 

That is essentially as it was explained to me. The signal "crosses over" from one driver to the next as the frequency changes.

[Edgar]

Weird. Don't know how that double post occurred.

[geoff.]

...it only happens to me when the FBI is monitoring my activity, but it may be different for you? 

[Edgar]

31 minutes ago, geoff. said:

...it only happens to me when the FBI is monitoring my activity, but it may be different for you? 

Nah, they gave up on me years ago. Checked into my background and couldn't believe that anybody's life could be so boring.

[Chief bonehead]

Balancing network…..contains crossover, eq, gain structure and anything else necessary to get the speaker curve the way we want it to be……as explained to me by Mr. K

[Travis In Austin]

4 hours ago, Edgar said:

Weird. Don't know how that double post occurred.

No filter?

 

[Travis In Austin]

3 minutes ago, Chief bonehead said:

Balancing network…..contains crossover, eq, gain structure and anything else necessary to get the speaker curve the way we want it to be……as explained to me by Mr. K

Ok now:

 

What is the significance of the fact that no sound in nature has constant phase?

[Edgar]

7 hours ago, Travis In Austin said:

Ok now:

 

What is the significance of the fact that no sound in nature has constant phase?

 

Nothing at all, as long as it is accurately reproduced by your loudspeaker.

[captainbeefheart]

15 hours ago, Edgar said:

Research into temporal masking tends to refute this concept. Separated by less than a certain threshold, the disparate arrival times cannot be discerned at all. That threshold is in tens or hundreds of milliseconds

 

I disagree. And millions of musicians will too.

 

For example one of my analog 'Chorus' effects has adjustable time delays between 600uS and 10mS and you can hear the difference between them. 10mS is just too long and sounds more like a 'delay' effect than an actual chorus effect. I like it set to 1mS, with this setting I can clearly hear the difference between the effect on vs off.

 

 

[Edgar]

1 hour ago, captainbeefheart said:

For example one of my analog 'Chorus' effects has adjustable time delays between 600uS and 10mS and you can hear the difference between them. 10mS is just too long and sounds more like a 'delay' effect than an actual chorus effect. I like it set to 1mS, with this setting I can clearly hear the difference between the effect on vs off.

 

 

 

It's a confusing lot. On one hand we have Zwicker and Fastl telling us that temporal post-masking lasts 200 ms and pre-masking lasts 25 ms. On the other hand, Kolbrek and Dunker say, "... They thought this would really show off the capabilities of the Fletcher system, and monitored [Eleanor Powell's] tap dance through it. Due to the 8-ft difference in path lengths through the two horns, every tap produced two taps from the speakers. By moving the high frequency unit back 8 ft, and then moving it forward again until an echo could barely be perceived, an acceptable upper limit of about 1 ms time delay was established." [High-Quality Horn Loudspeaker Systems, p. 309]

[captainbeefheart]

1 hour ago, Edgar said:

 

It's a confusing lot. On one hand we have Zwicker and Fastl telling us that temporal post-masking lasts 200 ms and pre-masking lasts 25 ms. On the other hand, Kolbrek and Dunker say, "... They thought this would really show off the capabilities of the Fletcher system, and monitored [Eleanor Powell's] tap dance through it. Due to the 8-ft difference in path lengths through the two horns, every tap produced two taps from the speakers. By moving the high frequency unit back 8 ft, and then moving it forward again until an echo could barely be perceived, an acceptable upper limit of about 1 ms time delay was established." [High-Quality Horn Loudspeaker Systems, p. 309]

 

There is a point where it doesn't sound like a delay and that's what they call a chorus effect because the time delay is so fast the two signals are almost in unison. In pro audio I believe anything over a 5mS delay is considered a 'delay' effect and that's where you can actually start to hear the second signal after the first. Anything under 5mS is considered a 'chorus' effect, like many people singing at the same time, the time delay is so fast it doesn't sound like a delay effect, it has a different sound to it that's hard to explain but sounds really good with instruments. It has a shimmering like rich tone to it that just sounds great.

 

Here is a link explaining it but more importantly there is an audio clip on the page that has a guitar player playing a riff without it and then with it, you do not perceive it as a delay but it is still very audible.

 

https://en.wikipedia.org/wiki/Chorus_(audio_effect)#Electronic_effect

 

 

[CWelsh]

I think of it as the Allman Brothers effect 😃

[Edgar]

42 minutes ago, CWelsh said:

I think of it as the Allman Brothers effect 😃

 

Dual motorcycle crashes?

 

Sorry, perhaps in poor taste.

[Edgar]

57 minutes ago, captainbeefheart said:

There is a point where it doesn't sound like a delay and that's what they call a chorus effect because the time delay is so fast the two signals are almost in unison. ...

 

Yes, I am familiar. Obviously none of the descriptions (temporal masking, tap dance, chorus, etc.) fit the situation exactly, hence the apparent contradictions. I agree that time and phase alignment are important in crossover networks. I just don't know how important they are in relation to all of the other things that are important. I have experimented a bit with it myself, and while "feet" seem to matter, "inches" don't ... at least not to my ears.

[captainbeefheart]

5 minutes ago, Edgar said:

 

Yes, I am familiar. Obviously none of the descriptions (temporal masking, tap dance, chorus, etc.) fit the situation exactly, hence the apparent contradictions. I agree that time and phase alignment are important in crossover networks. I just don't know how important they are in relation to all of the other things that are important. I have experimented a bit with it myself, and while "feet" seem to matter, "inches" don't ... at least not to my ears.

 

Well that's just it, many times these imperfections albeit are not suppose to be there and are not "faithful" to their inputs but sound good or are just benign. So you are correct in that even though technically it's an imperfection it's total effect on the overall acoustic output is either benign enough to not notice or the imperfection sounds good and adds something unique to the sound. Like harmonic distortion, not all distortion is dissonant, lower even orders are harmonious and somewhat benign, some even like the addition to 'warm' things up. 

 

It reminds me of people that give rave reviews of tube amps with tiny output transformers that tell us the bass is amazing. When in reality the core size isn't large enough to pass the low frequencies faithfully and the trailing edge falls apart giving rise to non-linear distortion. Well, non-linear distortion produces even harmonics and so at low frequencies this added harmonic distortion content fattens up the sound but is harmonious only being an octave above the fundamental. So something technically bad and is far from a faithful reproduction of it's input still sounds good. I have measured this many times on amps with small output transformers, distortion at 35Hz being 20% but still sounds good. Of course these amps shouldn't truly be called "hifi" many people like them. Not sure if you are following the Crimson 275 debacle but take that amp for example, people love the sound of it but the designer used over 600v for the plates and a load line to produce over 70 watts output but they use a 15 watt output transformer. The amp produces 75 watts with 2.8% THD at 1kHz, but at 35Hz and 32 watts output the distortion rises to 27%. People are just in disbelief of the specs but this was common with old console amps and such where output transformers would distort low frequencies but the amps still sounded great. There are some members here that have the Crimson 275 and love it but are a little miffed about the specs because the company are somewhat misleading with the specs, people are expecting less than 1% THD at 20Hz with 75 watts output. The stereo amp weighs 19 pounds, that should have a been a red flag right there.

[CWelsh]

37 minutes ago, Edgar said:

 

Dual motorcycle crashes?

 

Sorry, perhaps in poor taste.

Yikes! I was thinking Duane and Dickey doubling on guitar leads.

[Edgar]

Just now, CWelsh said:

Yikes! I was thinking Duane and Dickey doubling on guitar leads.

Yeah, I know. I was just in a foul mood. Apologies.