SL2000 response charts in sda compendium show no spikes

heiney9

candyliquor35m wrote: »

Raife,

Thanks for the charts. Someone on here has been asking for them for weeks now. They are everything I had hoped for and more.

We can finally put this debate to rest. There is and has never been a nasty spike at 13khz. As you say and all the reviews that have been written also confirm that there is a resonance at 13khz. A spike and resonance are completely two unrelated and different things.

"Resonance: 1. the state of being resonant. 2. a prolonged response or increase of sound in one body reacting to sound waves from another body that is vibrating."

To interpret the resonance at 13khz as a nasty spike would be completely false and completely misleading.

I will continue tweaking my polks as others are doing with x-over cap upgrades, internal wiring upgrades, binding post upgrades, etc. Just this week when I put on Celine Dion on my SRS's, she sounded a bit harsh and bright so I changed the single 1.0 uf cap on each of the 2 middle tweeters to 1 single .47 uf cap. It accomplished the reduction of the harshness and brightness but I lost too much of the soundstage for my taste. Eventually I might try a .68 uf cap on the 2 middle sl2000's.

Thanks for the charts and keep up the good reviews and such.

Maybe someday, Polk will let you publish charts for the rd0's.

Go back and read for the first time (like I suggested) or reread the Stereo Review article is states "5dB resonance peak at 13kHz......"

We've also determined the word peak and spike can mean the same thing especially in the vernacular of audio terminology.

Next..............................

H9

madmax

Years of listening to SDA's has caused hearing loss at 13khz so who cares anyway.
madmax

candyliquor35m

madmax wrote: »

Years of listening to SDA's has caused hearing loss at 13khz so who cares anyway.
madmax

I wish I was that lucky. Then all my problems would be over.

heiney9 wrote: »

Go back and read for the first time (like I suggested) or reread the Stereo Review article is states "5dB resonance peak at 13kHz......"

We've also determined the word peak and spike can mean the same thing especially in the vernacular of audio terminology.

Next..............................

H9

You are quite the comedian. You should hang out with clinton so you two can debate the meaning of the word 'is'.

Everyone knows that peak means the highest point (the peak of mount everest) and spike means an intense increase in elevation or khz .

This is best analogy I can think of. Listening to sdas with the sl2000 tweeter(s) is like being in the front row of a live concert but having a volume control to control the volume. If that is your cup of tea then you will love the sl2000 tweeters. If you like sitting in the 50th row then you will love the rd0194.

I haven't heard the rd0198 but having heard the sl3000, the sl3000 is like sitting in the 10th, 20th, or 30th row. It's been awhile since I listened to one so I can't be very precise with it.

DarqueKnight

candyliquor35m wrote: »

Raife,

A spike and resonance are completely two unrelated and different things.

Carl,

No, they are not two completely unrelated and different things. Spikes can cause resonances and resonances can cause spikes. A room that has a resonance (or reinforcement) at a particular frequency will cause a rise, and perhaps even a spike in the room's frequency response at that frequency. This is basic acoustics. Since I am familiar with audio engineering nominclature and terminology, when I hear someone speak of a "spike" at a particular frequency, I do not automatically visualize a dagger sticking up in the response curve. Depending on the design goal and application, a 2 or 3 dB rise might be considered a "spike".

candyliquor35m wrote: »

Everyone knows that peak means the highest point (the peak of mount everest) and spike means an intense increase in elevation or khz .

Everyone, except you, knows that the same word can have different, and even wildly different meanings depending on the application.

The problem with lacking fundamental knowledge in a subject is that it can cause one to get fixated on a particular word or misunderstanding of a concept. In your case, you expected to see a towering dagger-like "spike" in the SL2000's response characteristic. People knowledgable in acoustics and audio engineering know full well that dagger-like spikes (or dips) are never seen in well engineering audio components.

When the audio design goal is as little deviation from flat response as practically possible, a 5 dB rise absolutely qualifies as a "spike", even though it is not jutting up like a skyscraper above the other frequency response values.

candyliquor35m

DarqueKnight wrote: »

Carl,

No, they .

Raife, I respect and appreciate your opinion. I doubt if the majority of the readers here (including the 100 guests viewing right now) are as familiar with audio engineering nominclature and terminology as you are so I think it would be safer to use layman's terminology when describing the 13khz prominence/resonance in your response charts. A layman does think of a spike as a dagger like object such as a railroad tie spike or a spike for a tent and thus envisions a spike on a response chart to like those seen on lie detector tests.

So maybe we can come up with a term better suited and understood by the masses than the term "nasty spike" to describe the response chart of the sl2000.

Also, individually the highest peak of any one sl2000 is 10khz.

Does anyone know of a website where these frequencies can be played and heard individually. Like a flat 5, 10, 13... khz.

heiney9

This is priceless....................now CL35M is telling us how the people who frequent this site think and interpret posts.

Fricking hilarious. Raife and anyone else here can describe things anyway they want................if you or someone else doesn't understand it; get your learn on. Now you want us to "dumb" down our responses so as to appease you.

Raife and many others are very articulate in the responses they write (I'll include myself as well for the most part) if you or anyone else doesn't get it, then it's time to move on to something you can understand.

Nothing in this thread is rocket science. Your responses border on fantasy but the rest of the responses are easily understood by anyone with a 6th grade education. We aren't building a nuclear reactor here :rolleyes:

H9

Systems

candyliquor35m wrote: »

A spike and resonance are completely two unrelated and different things.

Actually the two are related,a spike in the response is the direct result of a resonance in the dome.For instance take a look at the response of this highly regarded metal dome tweeter.While it is one of the faves of DIY speaker builders(myself included) but as the graph shows it has a very nasty "spike" about 27khz.The spike is caused by a resonance or break up mode within the domes structure.Virtually all metal domes suffer from this type of problem but it is high enough in frequency and narrow enough in bandwidth that it is not audible.http://www.seas.no/images/stories/prestige/pdfdatasheet/h1212_27tbfc_g_datasheet.pdf

avguytx

All of this because CL has a hard on for these SL2000 tweeters.

candyliquor35m

GV#27 wrote: »

Actually the two are related,a spike in the response is the direct result of a resonance in the dome.For instance take a look at the response of this highly regarded metal dome tweeter.While it is one of the faves of DIY speaker builders(myself included) but as the graph shows it has a very nasty "spike" about 27khz.The spike is caused by a resonance or break up mode within the domes structure.Virtually all metal domes suffer from this type of problem but it is high enough in frequency and narrow enough in bandwidth that it is not audible.http://www.seas.no/images/stories/prestige/pdfdatasheet/h1212_27tbfc_g_datasheet.pdf

Now that's what I call a spike. There's nothing even resembling that on the sl2000 charts

IrishNiner

Wow! Quite a pissing match. In the words of that great philosopher Rodney King, "Can't we all just get along"

I wade in here with a great deal of trepidation. But, I too just upgraded from Sl1000 tweets in my SDA1's to the RDO-194's and could not be more happy. Even with just a few hours on them the RDO-194 tweeter is far superior for my tastes. Diana Krall's piano and Chris Botti's trumpet no longer make me whince with pain at higher volumes.

Just my 2 cents worth.

Farrell

madmax

IrishNiner wrote: »

Wow! Quite a pissing match. In the words of that great philosopher Rodney King, "Can't we all just get along"

I wade in here with a great deal of trepidation. But, I too just upgraded from Sl1000 tweets in my SDA1's to the RDO-194's and could not be more happy. Even with just a few hours on them the RDO-194 tweeter is far superior for my tastes. Diana Krall's piano and Chris Botti's trumpet no longer make me whince with pain at higher volumes.

Just my 2 cents worth.

Farrell

Only 12 posts and already causing a big ruckus... Good job!

Welcome to club polk.
madmax

Systems

madmax wrote: »

Only 12 posts and already causing a big ruckus... Good job!

What ya expect,he's Irish:D

Systems

candyliquor35m wrote: »

Now that's what I call a spike.

Yes and that spike is caused by a resonance.

There's nothing even resembling that on the sl2000 charts

Not all resonances appear as sharp spikes in the response it depends on the Q of that resonance.The resonance in that SEAS metal dome is of the hi Q variety.A tweeter with a low Q resonance in its response will have a peak in its response that will cover a wider range but will be lower in level.If this broad peak in response appears below 18-20khz then it will be audible.How audible will depend on its actual level and frequency.

DarqueKnight

candyliquor35m wrote: »

Maybe we can get raife to post the charts here so everyone can make up their own mind.

candyliquor35m wrote: »

That was before I saw the charts. I assumed you guys were telling the truth about the spike on the charts but if you look at raife's charts, there is no spike. My ears were telling me all along that there is no spike but I trusted and respected you guys not to spread false rumors.

candyliquor35m wrote: »

Thanks for the charts. Someone on here has been asking for them for weeks now. They are everything I had hoped for and more.

We can finally put this debate to rest. There is and has never been a nasty spike at 13khz.

Carl,

I hate to break up this love festival, but a little reality check is in order here. I refer you again to my statement on page 41 paragraph 1 of the Compendium 2nd Edition:

"I had always thought that the SL2000 resonance was due solely to the tweeter. I did some circuit SIMULATIONS in August of 2004 that showed that the 13,000 Hz prominence in the frequency response may have been due largely to the design of the crossover and subsequently aggravated by the SL2000 resonance."

The charts I published in the Compendiun and on the forum in August of 2004 are mere SIMULATIONS. They would be more accurate if the acutual electrical parameters of the tweeters had been built into the simulation, but since I did not have those values, I modeled the SL2000 tweeters as pure resistances. I specifically stated on page 43 of the Compendium:

"The electrical parameters of the SL2000 and SL3000 tweeters were not available; accordingly, they were modeled respectively as 7.5 ohm and 5.6 ohm resistive loads in the simulations. There are devices that will "read" the electrical parameters of a loudspeaker, however, Polk considers such specifications to be proprietary, and I did not want to invade their privacy."

The simulations I did are certainly in the "ballpark" of the SL2000's true response characteristic, but since some important electrical characteristics of the SL2000 were left out, I would not advise betting the farm on their absolute accuracy.

Even if I had included a true mathematical model of the SL2000's in the simulation, that would only be the theoretical model. Most of us know, and fully understand, that devices deviate from the theoretical model in actual real world practice.

Since this is of high importance to you, I would advise bribing someone at Polk to give you the true anechoic laboratory response characteristic and the response charts derived from a mathematically accurate simulation model. Once you obtain accurate response curves, you may very well find that railroad spike in the picture after all.

Good luck.

ben62670

I think the tags asy it best.

Dennis Gardner

I know that Carl doesn't interpret Raifes chart as a spike, but I don't think he understands how logarithmic frequencies work.

The chart shows that 13khz frequency is 5 dB obove 8khz and 16khz. Yes it looks gradual on the chart but in a simple musical scale, it is quite a difference in a small number of notes. There is only one octave of music from 8khz to 16khz, the note B8 is 7.9khz and B9 is 15.8khz.

So in laymans terms, the G# (13.2khz) in that range of notes is 5dB louder than the B on either side of it. That is quite a difference, compared to the rest of the speakers frequency response. One note being that much higher than others close to it may not qualify as a spike to Carl, but that single octave peaks higher than all 9 or 10 other octaves covered.

Oh yeah, can anyone tell by the lousy Seas chart what frequency that dip and spike are at? Poor chart reference from what I can tell.

TroyD

I'm honestly confused.

Let's assume that the FR responce on the SL2000 was without any sort of speak, hump, bump...whatever. Then why modify it, extensively, and claim that it eliminated the aforementioned artifact?

To do it because someone suggested in 2006 doesn't make sense? If the tweeter sounded fine to start with, why dick with it? So, now you are blaming us for doing something that may not have been neccessary? It doesn't compute, Carl. You are playing both sides of the issue. Either you heard it and agreed or you did it just to go along and the resulting pages of testimonials to the improved nature of you capped tweeter and the taming of the harshness was BS. WTF?

Hump/bump aside, either the tweeter sounds good or it doesn't. Does it need to get more complicated than that?

Now, if you determine that it doesn't sound good and you want to modify it, wouldn't it make sense for you to quantify what the issue is so you can make an educated attempt to correct it? In Carl's case that just hasn't happened. He's constantly shifting feet on the issue. Which, hell, it's his stuff, I could care less if he went Jimi H. and set it on fire. The problem that I have, and continue to have, is that he wants to tout his modified as a viable mod/alternative but he can't quantify in an intelligent meaningful way the basic issue much less his subsequent attempts to correct it.

That, and I LOVE his post on AK. You weren't talking about Polks? Really? What other speakers do you own, Carl, with the same exact issue? Why blatantly LIE about it? Kinda makes you wonder what else you have been playing loose with the truth on. You know, you can knock me for a lot of stuff, but dishonestly isn't one of them...and that's one of your basic issues Carl is that you aren't truthful. You know, I honestly don't think you are an evil person but the reason that people don't like you is that you are fundamentally dishonest which has been shown over and over. Just as a word of advice, in about any setting people will be willing to overlook just about any sort of personality issue but the one thing that sours people is when you are dishonest. Just a word of advice.

Have a great day, Carl. I know I am.

BDT

TroyD

DarqueKnight wrote: »

I don't think he was trolling. I think he was (sarcastically) pointing out the fact that some people only became dissatisfied with the SL2000 after other people pointed out its deficiencies. His screen name seems to indicate that he owns SDA 2's.

I agree with Raife...and here is my take on it, on the whole, I don't find speakers with the SL2000 objectionable. The highs are a bit peaky but, hey, nothing is perfect. If it were, nothing would ever evolve. I was perfectly happy with the SL3000's in my SDA's but I like the RDO's better. It's not a case of 'bad' or 'good' as it is incrementally better....make sense?

BDT

Systems

Dennis Gardner wrote: »

I

Oh yeah, can anyone tell by the lousy Seas chart what frequency that dip and spike are at? Poor chart reference from what I can tell.

The spike occurs in the 26-27 khz region.The two unlabeled vertical lines in the graph to the right of 10k represent 20k and 30 k.

read-alot

At this point in my life I'm only concerned about what matters most to me.......the sound

and if my amalgam fillings are keeping me from hearing it.

Dennis Gardner

GV#27 wrote: »

The spike occurs in the 26-27 khz region.The two unlabeled vertical lines in the graph to the right of 10k represent 20k and 30 k.

So dogs, cats, and bats are the only ones that find this peak objectionable....;)

candyliquor35m

It's sunday and all and I'm feeling a little guilty.

I know I haven't been as nice recently as I usually am.

So I want to reach out to everyone on the forum and apologize.

Please accept my deepest and heartfelt and sincere apology for distracting all of you from talking about Oprah

Systems

Dennis Gardner wrote: »

So dogs, cats, and bats are the only ones that find this peak objectionable....;)

Yep pretty much.:DThe response in the important 2-12k region is very linear and this tweeter sounds very smooth and sweet not etched like some of the older metal domes.

DollarDave

GV#27 wrote: »

Yep pretty much.:DThe response in the important 2-12k region is very linear and this tweeter sounds very smooth and sweet not etched like some of the older metal domes.

To be clear, you are talking about the Seas, not the sl-2000, right?

Systems

DaveMuell wrote: »

To be clear, you are talking about the Seas, not the sl-2000, right?

Yes ,I was refering to the SEAS unit.

daifanshi

DarqueKnight wrote: »

Since this is of high importance to you, I would advise bribing someone at Polk to give you the true anechoic laboratory response characteristic and the response charts derived from a mathematically accurate simulation model. Once you obtain accurate response curves, you may very well find that railroad spike in the picture after all.

Good luck.

Instead of bribing and theorizing to get to the end conclusion. The correct way to determine what is going on with the SL2000 tweeters is to make careful measurements of a physical sample. And they do not have to be anaechoic sine-wave sweeps. Gated burst tone measurements are mathematically equivalent and can be done almost anywhere. And as far as I know, there are no publically available distortion tests available either. We need these too.

Plots of the in-room response of the entire speaker system such as those found in magazines or done with your SPL meter in your living room are of limited utility, since the environment is not typically known or repeatable, and over-averaging can really skew the results. System tests also can't be used to extract accurate imformation about the drivers because of crossover electrical effects.

I have already started the process of measurements of the SL3000 tweeter and MW6510 woofer for my own purposes. I finished my impedance measurements already and will be able to extract the Thiel-Small parameters shortly. These will be as close to reality as one can get and not taken from fresh engineering samples built and measured in the mid 80's, but well-aged and broken-in units.

With respect to the tweeter, there are several things that can cause "sibilance", "peaking", "harshness", etc... From reading this board, the folklore here says we have a "spike", "peak", "bump" in the frequency response around 13kHz.

Instantaneous frequency response is only a superficial indication that a problem might exist. I will make "standard" frequency response measurements but also important are the following:

1. Stored energy in the tweeter response. Waterfall plots are useful in seeing this. e.g. A "peak" can sound bad, but a smaller "peak" will sound worse if it stays with the tweeter for several hundred milliseconds. I have the ability to test this. I've heard this called "linear" distortion.

2. Non-linear distortion. Also known as intermodulation distortion. These are basically mixing products (a non-linear effect) that happen when multiple-tones (as in music) modulate with one another and produce other tones. These "sub-tones" can be large compared to the desired tones and the odd-order tones are close in to the desired tones, which can make them the worst offending. This distortion is different depending on frequency and is always worse when operating a tweeter at too low a frequency. This is due to the non-linearities in the motor when there are large excursions. I can make this measurement as well.

3. And of course all the effects I listed above are power-dependent. I can test this but I won't. Too tedious. But the effect can be very significant as the voice coil heats up.


Cheers.

ben62670

You can polish a ****, but it is still a ****. The SL 2000 doesn't age well, and wasn't the greatest to begin with.
Ben

F1nut

Judging from Ben's post, I'd have to say that CL's buddy (on the Bozo list for a damn good reason) is back to talk about a tweeter that he doesn't possess nor has any use for since his speakers use the SL3000. What a hoot!

daifanshi

F1nut wrote: »

Judging from Ben's post, I'd have to say that CL's buddy (on the Bozo list for a damn good reason) is back to talk about a tweeter that he doesn't possess nor has any use for since his speakers use the SL3000. What a hoot!

F1nut,

I noticed these veiled attacks only appear from you when something even vaguely technical is presented. If you don't understand what I'm posting about, I'll gladly point you to resources that can help you if my postings are not clear enough. And I can clarify things via PM's if they can be explained that way.

Sometimes it can take a real effort to understand things, especially if one doesn't have a real relevant technical background either through experience or education. For example, I find music theory very frustrating and complex, but the end results can be real rewarding if one perseveres.

Cheers.

heiney9

daifanshi wrote: »

Instead of bribing and theorizing to get to the end conclusion....... Blah, Blah, Blah edited for the sake of sanity

Blah, blah, blah............Professional tests revealed the peak, Polk admitted the peak, the sl2000 sounds harsh, strident, strained, shrill and the RD0 sounds better. I don't need any tests to prove what I hear and already have been able to deduce.

H9