I Love SL2000 Tweeters
Comments
-
Does anyone have the same chart for the replacement RDO tweeters?
-
Aud10n3wb13, thanks again for those frequency response graphs. They are very enlightening.
Here is a quote from a Polk Audio technical paper, dated September 1989, discussing general characteristics of dome tweeters:
"Dome tweeters, characteristically, have either a peak in response somewhere in the top octave or a roll-off above 12 to 15 kHz (for a 1" dome).Through the use of laser interferometry we were able to link these two characteristics to a common phenomenon. In virtually all 1 inch soft dome tweeters a standing wave was observed on the surface of the dome, usually in the 12 to 15 kHz frequency range. This standing wave phenomenon, if untreated, led to a peak in the response at the same frequency.
However, if sufficient damping material is added to the dome to control the standing wave resonance, output above that frequency drops off rapidly."Proud and loyal citizen of the Digital Domain and Solid State Country! -
DarqueKnight wrote: »Aud10n3wb13, thanks again for those frequency response graphs. They are very enlightening.
Here is a quote from a Polk Audio technical paper, dated September 1989, discussing general characteristics of dome tweeters:
"Dome tweeters, characteristically, have either a peak in response somewhere in the top octave or a roll-off above 12 to 15 kHz (for a 1" dome).Through the use of laser interferometry we were able to link these two characteristics to a common phenomenon. In virtually all 1 inch soft dome tweeters a standing wave was observed on the surface of the dome, usually in the 12 to 15 kHz frequency range. This standing wave phenomenon, if untreated, led to a peak in the response at the same frequency.
However, if sufficient damping material is added to the dome to control the standing wave resonance, output above that frequency drops off rapidly."
I'm not sure what relation you are seeing in the quote you posted to the graphs that are posted.
What I think I'm seeing in the graphs is that the caps are causing a much more rapid falloff except for a couple extreme peaks. Those extreme peaks and even that gigantic dip around 3 kHz are likely caused by resonances developing from harmonics produced by the caps shoving the crossover point up the frequency range. Especially if it's a 2.2 MFD cap and pushing crossover points up to the 9 kHz range. The harmonics would be at spots like a 3 kHz dip or an insane peak right around 18 kHz on a 3 or even 6 dB slope. They would still have similar issues even at a 12 kHz crossover point on a 6 ohm load because a 3 or 6 dB slope would still likely cause untamed harmonics in the same spots. The drastic falloff seems to happen after the 10 kHz range which I would expect. The caps seem to be exaggerating the standing wave resonance that the quote mentions though. Maybe because of the harmonics manifesting at that frequency point?
I'm not trying to be a jerk, just trying to understand what relationship you see.Expert Moron Extraordinaire
You're just jealous 'cause the voices don't talk to you! -
Is there by chance a crossover schematic for that speaker kicking around somewhere?Testing
Testing
Testing -
Is there by chance a crossover schematic for that speaker kicking around somewhere?
See here:
http://www.polkaudio.com/forums/showpost.php?p=434476&postcount=2
H9"Appreciation of audio is a completely subjective human experience. Measurements can provide a measure of insight, but are no substitute for human judgment. Why are we looking to reduce a subjective experience to objective criteria anyway? The subtleties of music and audio reproduction are for those who appreciate it. Differentiation by numbers is for those who do not".--Nelson Pass Pass Labs XA25 | EE Avant Pre | EE Mini Max Supreme DAC | MIT Shotgun S1 | Pangea AC14SE MKII | Legend L600 | BlueSound Node 3 - Tubes add soul! -
Thank you sir.
Ok by adding the 2.2 cap the xover has changed from a second order 12 db to a third order 18 db.Although normally the cap followong the coil is larger than the one before it.This will steepen the rolloff and change the phase relationship between the tweeter and woofers but it should not push the xover point up to 10k ish because the caps are not simply in series as they have an inductor between them.I would expect the response in the crossover region to change some.Testing
Testing
Testing -
Thank you sir.
Ok by adding the 2.2 cap the xover has changed from a second order 12 db to a third order 18 db.Although normally the cap followong the coil is larger than the one before it.This will steepen the rolloff and change the phase relationship between the tweeter and woofers but it should not push the xover point up to 10k ish because the caps are not simply in series as they have an inductor between them.I would expect the response in the crossover region to change some.
But wait, if the capacitor that CL is jacking into the mix is wired in the way that his picture is showing, it's wired in series with the tweeter but the 0.4mH inductor and the 2.7 ohm 5w resistor are wired in series with each other but parallel to the speaker. Would that change the order of the crossover or am I confusing myself by trying to logically work this illogically applied cap into the mix?Expert Moron Extraordinaire
You're just jealous 'cause the voices don't talk to you! -
Does anyone have the same chart for the replacement RDO tweeters?
For sure, someone can send me a pair or RDO194 so I can create the graphs as well.
hehehe -
Yes if it is configured like the tweeter section in the RTA 11T.It will increase the slope of the rolloff .But wait, if the capacitor that CL is jacking into the mix is wired in the way that his picture is showing, it's wired in series with the tweeter but the 0.4mH inductor and the 2.7 ohm 5w resistor are wired in series with each other but parallel to the speaker. Would that change the order of the crossover or am I confusing myself by trying to logically work this illogically applied cap into the mix?Testing
Testing
Testing -
1 cap in series = 1st order (90 degree phase shift)
1 cap in series followed by coil in parallel = 2nd order (180 degree phase shift)
1 cap in series followed by coil in parallel followed by another cap in series = 3rd order (270 degree phase shift)
See the pattern? This is for high-pass crossovers. -
I'm not sure what relation you are seeing in the quote you posted to the graphs that are posted.DarqueKnight wrote: »The graph without the cap shows a 5 dB peak at approximately 13 kHz and a rolloff after that point. Your results are close to the classic response characteristic for the SL2000 tweeter.
What is interesting is that the graph with the cap shows the same 5 dB peak at 13 kHz, yet with a more severe rolloff after the peak with a 13 dB null at about 15 kHz and a new 3 dB spike at about 17 kHz.
The 29 dB null at around 3 kHz is of some concern because the fundamental frequency components of female voices and some instruments are being attenuated.DarqueKnight wrote: »Here is a quote from a Polk Audio technical paper, dated September 1989, discussing general characteristics of dome tweeters:
"Dome tweeters, characteristically, have either a peak in response somewhere in the top octave or a roll-off above 12 to 15 kHz (for a 1" dome).Through the use of laser interferometry we were able to link these two characteristics to a common phenomenon. In virtually all 1 inch soft dome tweeters a standing wave was observed on the surface of the dome, usually in the 12 to 15 kHz frequency range. This standing wave phenomenon, if untreated, led to a peak in the response at the same frequency.
However, if sufficient damping material is added to the dome to control the standing wave resonance, output above that frequency drops off rapidly."
....Proud and loyal citizen of the Digital Domain and Solid State Country! -
1 cap in series = 1st order (90 degree phase shift)
1 cap in series followed by coil in parallel = 2nd order (180 degree phase shift)
1 cap in series followed by coil in parallel followed by another cap in series = 3rd order (270 degree phase shift)
See the pattern? This is for high-pass crossovers.
I understand that part but from what I'm seeing, the cap is in series with the tweeter but preceded by the coil in parallel. I didn't think that would change the order because the cap is in line after the inductance coil.
I could be wrong though. I know how crossovers work and how slopes and such relate to frequency response but crossover schematics always seem to confuse me.Expert Moron Extraordinaire
You're just jealous 'cause the voices don't talk to you! -
DarqueKnight wrote: »..Quote:
Originally Posted by Jstas View Post
I'm not sure what relation you are seeing in the quote you posted to the graphs that are posted.Quote:
Originally Posted by DarqueKnight View Post
The graph without the cap shows a 5 dB peak at approximately 13 kHz and a rolloff after that point. Your results are close to the classic response characteristic for the SL2000 tweeter.
What is interesting is that the graph with the cap shows the same 5 dB peak at 13 kHz, yet with a more severe rolloff after the peak with a 13 dB null at about 15 kHz and a new 3 dB spike at about 17 kHz.
The 29 dB null at around 3 kHz is of some concern because the fundamental frequency components of female voices and some instruments are being attenuated.
..Quote:
Originally Posted by DarqueKnight View Post
Here is a quote from a Polk Audio technical paper, dated September 1989, discussing general characteristics of dome tweeters:
"Dome tweeters, characteristically, have either a peak in response somewhere in the top octave or a roll-off above 12 to 15 kHz (for a 1" dome).Through the use of laser interferometry we were able to link these two characteristics to a common phenomenon. In virtually all 1 inch soft dome tweeters a standing wave was observed on the surface of the dome, usually in the 12 to 15 kHz frequency range. This standing wave phenomenon, if untreated, led to a peak in the response at the same frequency.
However, if sufficient damping material is added to the dome to control the standing wave resonance, output above that frequency drops off rapidly."
OK, are you saying that even with the capacitor in place, the standing waves that cause the harshness that CL is whining about are still there even with the caps? Because that is what it honestly looks like to me. The hump is still there with a much more drastic rolloff and all the caps serve to do is attenuate response above about 10.5 kHz but don't really affect the hump that they are intended to fix at all.Expert Moron Extraordinaire
You're just jealous 'cause the voices don't talk to you! -
OK, are you saying that even with the capacitor in place, the standing waves that cause the harshness that CL is whining about are still there even with the caps?
That was exactly the point I was trying to make.The hump is still there with a much more drastic rolloff and all the caps serve to do is attenuate response above about 10.5 kHz but don't really affect the hump that they are intended to fix at all.
Absolutely. That is why I said it was so "interesting".
Review:
DarqueKnight wrote: »The graph without the cap shows a 5 dB peak at approximately 13 kHz and a rolloff after that point. Your results are close to the classic response characteristic for the SL2000 tweeter.DarqueKnight wrote: »What is interesting is that the graph with the cap shows the same 5 dB peak at 13 kHz, yet with a more severe rolloff after the peak with a 13 dB null at about 15 kHz and a new 3 dB spike at about 17 kHz.DarqueKnight wrote: »The 29 dB null at around 3 kHz is of some concern because the fundamental frequency components of female voices and some instruments are being attenuated.Proud and loyal citizen of the Digital Domain and Solid State Country! -
Standing waves are a result of the mechanical structure of the dome so must be dealt with by adding damping either by coating it with something or using a different surround material etc.You can't eliminate the SW with crossover parts but you can reduce the resulting resonance peak with a notch filter.A simple cap will not help.OK, are you saying that even with the capacitor in place, the standing waves that cause the harshness that CL is whining about are still there even with the caps?Testing
Testing
Testing -
Standing waves are a result of the mechanical structure of the dome so must be dealt with by adding damping either by coating it with something or using a different surround material etc.You can't eliminate the SW with crossover parts but you can reduce the resulting resonance peak with a notch filter.A simple cap will not help.
OOOOOhhhhhhh! I get what you're saying now!
Sorry, it's a "dumb" day for me I guess. Too much Easter candy yesterday I guess.Expert Moron Extraordinaire
You're just jealous 'cause the voices don't talk to you! -
DarqueKnight wrote: »That was exactly the point I was trying to make.
Absolutely. That is why I said it was so "interesting".
Gotcha.
So License2ill, still think that everybody is just a bunch of "wanna-be's"? You have someone who did way better than the math and actually tested out CL's "tweak" and has shown unequivocally, without a doubt, that it doesn't do squat.
candyliquor35m, I think it's time you can your stupid "part number" thing along with your diatribes about how great it is with no backing information at all. It's grown wearisome.
I think this thread can stop here because there isn't anything left to discuss. The "mod" doesn't work, the "tweakers" are alive and well in Club Polk and like I said before, obey Physics! It's the law! If you think your ears are telling you that the "mod" works and you are happy with it, fine, enjoy! More power to you! But stop telling the rest of us that the science is wrong because you say it is and that's that.Expert Moron Extraordinaire
You're just jealous 'cause the voices don't talk to you! -
I could care less about the spike. I've never heard it and probably nobody else has. It's only on paper.
"On paper means diddly squat as you've found out." F1Nut
I had a nice conversation with the older, very knowledgeable gentleman at epohouston.com and he explained it to a T.
The harshness isn't coming from the upper most frequencies that the tweeter is producing because no one can hear that high. The harshness is coming from the lower frequencies that the tweeter is producing and the only way to change/correct that is with a cap by changing the crossover point. He didn't think a 1.0 uf or 2.2 uf would change it enough but I'm using the 1.0 uf in the middle tweeter of the 2.3's and a 2.2 on the single tweeter in my 2B's. I'm currently using and experimenting with a 1.0 + a 2.2 in series on the 3rd tweeter from the top in my SRS's.
No one said this hobby was easy
-
Nice job guys!!!
-
DK, Jstas et al.....thanks, I've actually learned something.
Carl, just stop it.
BDTI plan for the future. - F1Nut -
You have someone who did way better than the math and actually tested out CL's "tweak" and has shown unequivocally, without a doubt, that it doesn't do squat.
candyliquor35m, I think it's time you can your stupid "part number" thing along with your diatribes about how great it is with no backing information at all. It's grown wearisome.
I know this isn't related, but if this were a thread about interconnects or speaker cable a bunch of people (and I'm not saying you Jstas) would be screaming the opposite. "Use your ears!" "The brain hears things that can't be explained!" "electronics can't measure everything!" "science and math can't explain everything!"
W -
candyliquor35m wrote: »I could care less about the spike. I've never heard it and probably nobody else has. It's only on paper.
"On paper means diddly squat as you've found out." F1Nut
I had a nice conversation with the older, very knowledgeable gentleman at epohouston.com and he explained it to a T.
The harshness isn't coming from the upper most frequencies that the tweeter is producing because no one can hear that high. The harshness is coming from the lower frequencies that the tweeter is producing and the only way to change/correct that is with a cap by changing the crossover point. He didn't think a 1.0 uf or 2.2 uf would change it enough but I'm using the 1.0 uf in the middle tweeter of the 2.3's and a 2.2 on the single tweeter in my 2B's. I'm currently using and experimenting with a 1.0 + a 2.2 in series on the 3rd tweeter from the top in my SRS's.
No one said this hobby was easy
The peak is definetly there. Polk engineers have even admitted it. I'd tend to choose the option of the manufacturer and designers way of alleviating the issue, that is purchasing a newer tweeter which has been R & D'd to address the original shortcomings of the sl2000. Rather than some old guy at epohouston.com.
Call me crazy but that seems to be the best option.
H9"Appreciation of audio is a completely subjective human experience. Measurements can provide a measure of insight, but are no substitute for human judgment. Why are we looking to reduce a subjective experience to objective criteria anyway? The subtleties of music and audio reproduction are for those who appreciate it. Differentiation by numbers is for those who do not".--Nelson Pass Pass Labs XA25 | EE Avant Pre | EE Mini Max Supreme DAC | MIT Shotgun S1 | Pangea AC14SE MKII | Legend L600 | BlueSound Node 3 - Tubes add soul! -
candyliquor35m wrote: »I could care less about the spike. I've never heard it and probably nobody else has. It's only on paper.
"On paper means diddly squat as you've found out." F1Nut
I had a nice conversation with the older, very knowledgeable gentleman at epohouston.com and he explained it to a T.
The harshness isn't coming from the upper most frequencies that the tweeter is producing because no one can hear that high. The harshness is coming from the lower frequencies that the tweeter is producing and the only way to change/correct that is with a cap by changing the crossover point. He didn't think a 1.0 uf or 2.2 uf would change it enough but I'm using the 1.0 uf in the middle tweeter of the 2.3's and a 2.2 on the single tweeter in my 2B's. I'm currently using and experimenting with a 1.0 + a 2.2 in series on the 3rd tweeter from the top in my SRS's.
No one said this hobby was easy
*SIGH*
Dude, you've been owned, hardcore at that. You have been shown that you performed an EPIC fail at tweaking your speakers because some sales monkey on a website got his math wrong and said it was a good idea. You've been shown graphs resulting from actual testing procedures, quotes from the actual engineers that designed and built the damn things and a bevy of people much smarter than you and me have told you how wrong you are. It's not the "paper" that is telling you that you are wrong, it's PHYSICS!
Physics hates you.
I think I agree with physics. You're a nattering moron that will believe anything you hear. You are a detriment to society, not just this forum, because of the fact that you'll believe anything you hear. You have nothing of value to offer anyone here at this point. You should find some place else to waste your time 'cause Club Polk is clearly too grounded in reality to deal with your illogical ramblings and out-of-context quotes.
I'm done.
Somebody lock this thread and put CL on ban again before he offers more half-assed advice.Expert Moron Extraordinaire
You're just jealous 'cause the voices don't talk to you! -
I know this isn't related, but if this were a thread about interconnects or speaker cable a bunch of people (and I'm not saying you Jstas) would be screaming the opposite. "Use your ears!" "The brain hears things that can't be explained!" "electronics can't measure everything!" "science and math can't explain everything!"
To a certain extent, yes.
If Carl likes what he hears, more power to him. However, he's peddling snake oil. Those of us that have owned the SL2000 know what we hear as well. The cap doesn't tame the spike that even Polk has admitted causes the issue, if anything it should make it all the more prominent.
Again, I'm all for doing what you want, even at the expense of common sense but don't try and pass **** as shoe polish either.
BDTI plan for the future. - F1Nut -
I know this isn't related, but if this were a thread about interconnects or speaker cable a bunch of people (and I'm not saying you Jstas) would be screaming the opposite. "Use your ears!" "The brain hears things that can't be explained!" "electronics can't measure everything!" "science and math can't explain everything!"
W
The point is not about CL's ears. If he likes how it sounds, great, more power to him. This is about CL diseminating misinformation and passing it off as fact with no basis. When he is presented with actual measured results backing up known and proven scientific facts, he calls on the "Listen with your ears!" argument and it's a "red herring" because it is meant to distract the reader from the actual facts posed in the opposing argument that actually refute his argument.
Don't try and play devil's advocate or be a hero. CL refused to back down so he got beat down.Expert Moron Extraordinaire
You're just jealous 'cause the voices don't talk to you! -
PLEEEEEEEEEEEEEZ lock this thread!!
but wait....why do I keep reading the damn thing!!??
Yep, my name really is Bob.
Parasound HCA1500A(indoor sound) and HCA1000(outdoor sound), Dynaco PAS4, Denon DP1200 w/Shure V15 Type V and Jico SAS stylus, Marantz UD7007, Polk L600, Rythmik L12 sub. -
I prefer to leave the speaker design (including capacitors, cross-over modifications, etc) to Polk Audio, Thiel, etc.
I'm smart enough to know that I'm not smart enough to make any significant improvement.
I'm still stuck on the lamp-cord vs. high-end-speaker wire debate. I'm confused now... some very respectable people say that they like Cardas because it adds color and they like color in their speaker wire. Yet, others say that wire is wire and it makes no difference.
I do know that adding capacitance to alter the properties of your speaker can't be a simple thing. The entire feng-shui of the speaker system has now been disrupted and a worm-hole is likely to develop which will swallow the universe whole. I digress. -
As the Polks turn."He who fights with monsters should look to it that he himself does not become a monster. And when you gaze long into an abyss the abyss also gazes into you." Friedrich Nietzsche
-
yeah instead of adding a band aid to the old one(like a notch filter) which they may have felt was unsalvagable, they started fresh with a complete new design.The peak is definetly there. Polk engineers have even admitted it. I'd tend to choose the option of the manufacturer and designers way of alleviating the issue, that is purchasing a newer tweeter which has been R & D'd to address the original shortcomings of the sl2000.Testing
Testing
Testing -
I'm thinking Polk outsourced the solution rather than start-up the old "silver-coil SL2000 production line". Two birds. One stone.
This discussion has been closed.