SL2000 tweeter frequency response plots anybody?

daifanshi
daifanshi Posts: 46
edited June 2008 in Vintage Speakers
I'm looking for an anaechoic frequency response plot of the SL2000 tweeter. One that clearly shows the +6db 10-13khz resonance that most believe is the cause of that tweeter's "harshness".

Or if there is a magazine review of the 1980's vintage Polk speakers that show that response resonance in good detail that would be helpful too.

Unfortunately I don't a SL2000 tweeter of my own...

Any other details such as the electrical and mechanical parameters will be useful too (if they exist in the public domain).

The purpose is to build an active filter to null the resonance at line level.

Thanks!
Post edited by daifanshi on
· Share on FacebookShare on Twitter

Comments

  • DarqueKnight
    DarqueKnight Posts: 6,765
    edited June 2008
    I was tolk by a Polk employee that the company considers the electrical and mechanical parameters, as well as the response characteristics of the SL2000 tweeter to be proprietary information. Oddly enough, they did publish the response curve for the SL3000 tweeter in a technical paper dated September 1989. The technical paper is titled "SL 3000 Dome Tweeter".

    High Fidelity magazine published a room response chart in their review of the SDA SRS 2 (November 1986, page 37).

    Active equalization of the type you are proposing will have some other undesirable effects which may be worse than the SL2000 resonance.

    My posts in this thread (beginning at post #10) may provide some useful insight: SDA-SRS Crossover Points
    Proud and loyal citizen of the Digital Domain and Solid State Country!
    · Share on FacebookShare on Twitter
  • dorokusai
    dorokusai Posts: 25,577
    edited June 2008
    Buy the new replacement tweeter....problem solved.
    CTC BBQ Amplifier, Sonic Frontiers Line3 Pre-Amplifier and Wadia 581 SACD player. Speakers? Always changing but for now, Mission Argonauts I picked up for $50 bucks, mint.
    · Share on FacebookShare on Twitter
  • danger boy
    danger boy Posts: 15,722
    edited June 2008
    dorokusai wrote: »
    Buy the new replacement tweeter....problem solved.

    that's to easy of a solution.. and it makes sense :p
    PolkFest 2012, who's going>?
    Vancouver, Canada Sept 30th, 2012 - Madonna concert :cheesygrin:
    · Share on FacebookShare on Twitter
  • daifanshi
    daifanshi Posts: 46
    edited June 2008
    DarqueKnight wrote: »
    I was tolk by a Polk employee that the company considers the electrical and mechanical parameters, as well as the response characteristics of the SL2000 tweeter to be proprietary information. Oddly enough, they did publish the response curve for the SL3000 tweeter in a technical paper dated September 1989. The technical paper is titled "SL 3000 Dome Tweeter".

    High Fidelity magazine published a room response chart in their review of the SDA SRS 2 (November 1986, page 37).

    Active equalization of the type you are proposing will have some other undesirable effects which may be worse than the SL2000 resonance.

    My posts in this thread (beginning at post #10) may provide some useful insight: SDA-SRS Crossover Points

    Can you tell me specifically what "undesirable effects" you are referring to? Just curious...
    · Share on FacebookShare on Twitter
  • daifanshi
    daifanshi Posts: 46
    edited June 2008
    dorokusai wrote: »
    Buy the new replacement tweeter....problem solved.

    I've heard this is the standard solution to the SL2000 problem. Unfortunately at 50 bucks a tweeter, this is expensive for a lot of people. Especially true if you have an one of the the SDA speaker systems with the SL2000.

    An active filter is an elegant solution that takes a few IC's and a power supply. For those with technical ability and more time than money, it will certainly be less than the cost of one tweeter.
    · Share on FacebookShare on Twitter
  • DarqueKnight
    DarqueKnight Posts: 6,765
    edited June 2008
    daifanshi wrote: »
    An active filter is an elegant solution that takes a few IC's and a power supply. For those with technical ability and more time than money, it will certainly be less than the cost of one tweeter.
    daifanshi wrote: »
    Can you tell me specifically what "undesirable effects" you are referring to? Just curious...

    How about sound quality? You are proposing to improve the sound of the SL2000, yet you want to run the signal through a few cheap IC's.
    Proud and loyal citizen of the Digital Domain and Solid State Country!
    · Share on FacebookShare on Twitter
  • daifanshi
    daifanshi Posts: 46
    edited June 2008
    DarqueKnight wrote: »
    How about sound quality? You are proposing to improve the sound of the SL2000, yet you want to run the signal through a few cheap IC's.

    This is a curious statement and not very specific. :confused: I don't know where the "cheap IC" assumption came from. But very high performance audio op amps such as TI OPA2604's are available for around 4 bucks a pop at small quantity. And nothing is being touched in the speaker system, we're just adding a few good op-amps to the preamp signal chain.

    The only thing I believe that can possibly cause problems is differential group delay if the notch filter is very deep. But then this potential "problem" is only localized to the frequency resonance anyways and that 6dB peak is gonna be much worst than a few hundred micro seconds of localized group delay.

    I GUARANTEE that OPA2604's are better than any of the dozen or so op-amps and transistors that were in the studio's mixing console or are in most people's CD players, preamps, or power amps today. There's lots of audio electronics from the 80's, 90's, and now that have old NE5532 and TL072 op-amps in them. :eek:
    · Share on FacebookShare on Twitter
  • ben62670
    ben62670 Posts: 15,969
    edited June 2008
    Its not just the 12k bump. The SL2000 deteriorates with age more like milk than whiskey. They are not just harsh at the bump, but the breakup/harshness is heard in lower frequency ranges. Look at the schematic, and at least replace the two tweeters that run near full range. Remember give them time to burn in. They are fairly harsh in the beginning.
    Ben
    Please. Please contact me a ben62670 @ yahoo.com. Make sure to include who you are, and you are from Polk so I don't delete your email. Also I am now physically unable to work on any projects. If you need help let these guys know. There are many people who will help if you let them know where you are.
    Thanks
    Ben
    · Share on FacebookShare on Twitter
  • MillerLiteScott
    MillerLiteScott Posts: 2,561
    edited June 2008
    This reminds me of the smell of hot tar.:eek:
    I like speakers that are bigger than a small refrigerator but smaller than a big refrigerator:D
    · Share on FacebookShare on Twitter
  • F1nut
    F1nut Posts: 50,735
    edited June 2008
    MillerLiteScott wrote: »
    This reminds me of the smell of hot tar.:eek:

    WAAAAAAAAAAAAAAAAAAAAAAAAAA
    Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."

    President of Club Polk

    · Share on FacebookShare on Twitter
  • ShinAce
    ShinAce Posts: 1,194
    edited June 2008
    Didn't CandyLiquor's thread(ss) about using caps end up with someone posting RTA analysis of the Sl2000 with and without mod?

    This was maybe 2-3 months ago. I can't remember the members name who posted the info, unfortunately.
    · Share on FacebookShare on Twitter
  • Face
    Face Posts: 14,340
    edited June 2008
    You claim to own a pair of TL's, but you're so interested in the SL2000's... :rolleyes:
    "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
    · Share on FacebookShare on Twitter
  • DarqueKnight
    DarqueKnight Posts: 6,765
    edited June 2008
    MillerLiteScott wrote: »
    This reminds me of the smell of hot tar.:eek:

    Thanks. I didn't want to be the one to say it.;)
    Proud and loyal citizen of the Digital Domain and Solid State Country!
    · Share on FacebookShare on Twitter
  • daifanshi
    daifanshi Posts: 46
    edited June 2008
    Face wrote: »
    You claim to own a pair of TL's, but you're so interested in the SL2000's... :rolleyes:

    An active notch filter is such a simple circuit for those who have used them and I enjoy working with active filters in general.

    I'm sure there are many who can't afford the cost of replacing their tweeters to fix response problems with the SL2000. If I'm guilty of anything, it's offering my expertise for free. I'm sorry if that offends anybody. :(
    · Share on FacebookShare on Twitter
  • F1nut
    F1nut Posts: 50,735
    edited June 2008
    If I'm guilty of anything, it's offering my expertise for free.

    Interesting comment considering that you don't have any experience with SDA's.
    Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."

    President of Club Polk

    · Share on FacebookShare on Twitter
  • daifanshi
    daifanshi Posts: 46
    edited June 2008
    F1nut wrote: »
    Interesting comment considering that you don't have any experience with SDA's.

    :confused:

    I own a pair. Is there something more that qualifies as "experience"? I also removed the crossover on one to examine it. I fixed a cold solder joint that looked like it was close to intermittent.
    · Share on FacebookShare on Twitter
  • F1nut
    F1nut Posts: 50,735
    edited June 2008
    daifanshi wrote: »
    :confused:

    I own a pair. Is there something more that qualifies as "experience"? I also removed the crossover on one to examine it. I fixed a cold solder joint that looked like it was close to intermittent.

    Thanks for proving my point.
    daifanshi wrote: »
    I recently bought a pair of 2.3TL's locally from craigslist for a very reasonable price.
    Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."

    President of Club Polk

    · Share on FacebookShare on Twitter
  • daifanshi
    daifanshi Posts: 46
    edited June 2008
    F1nut wrote: »
    Thanks for proving my point.

    You're welcome. :cool:
    · Share on FacebookShare on Twitter
  • heiney9
    heiney9 Posts: 25,204
    edited June 2008
    daifanshi wrote: »
    I'm looking for an anaechoic frequency response plot of the SL2000 tweeter. One that clearly shows the +6db 10-13khz resonance that most believe is the cause of that tweeter's "harshness".

    Or if there is a magazine review of the 1980's vintage Polk speakers that show that response resonance in good detail that would be helpful too.

    Unfortunately I don't a SL2000 tweeter of my own...

    Any other details such as the electrical and mechanical parameters will be useful too (if they exist in the public domain).

    The purpose is to build an active filter to null the resonance at line level.

    Thanks!

    It's been mentioned and perhaps plotted in a few "stereo" rags of the day when some of the Polk speakers were tested when new. Check out your local library or an on-line resource. That's likely as close as you will come to any kind of accurate, controlled meaningful measurement. The info from Polk is proprietary and they don't share those types of things publicly.

    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!
    · Share on FacebookShare on Twitter
  • heiney9
    heiney9 Posts: 25,204
    edited June 2008
    Also, impress us....................use the search function. Everything you have talked about in all your threads concerning the tweeter and ways of improving the SDA have been discussed many times on this board. Your questions aren't unique and answers to everything you've asked has been answered multiple times. Make the effort and do the research. If you really want to know then spending a little time reading won't hurt you.

    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!
    · Share on FacebookShare on Twitter
  • ben62670
    ben62670 Posts: 15,969
    edited June 2008
    What do you know. No CL here either.
    Please. Please contact me a ben62670 @ yahoo.com. Make sure to include who you are, and you are from Polk so I don't delete your email. Also I am now physically unable to work on any projects. If you need help let these guys know. There are many people who will help if you let them know where you are.
    Thanks
    Ben
    · Share on FacebookShare on Twitter
  • heiney9
    heiney9 Posts: 25,204
    edited June 2008
    ben62670 wrote: »
    What do you know. No CL here either.

    Nah....he's on Craigslist looking for cars to post in the Vintage Automobile thread he started. :D

    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!
    · Share on FacebookShare on Twitter
  • ben62670
    ben62670 Posts: 15,969
    edited June 2008
    Another funny thing... All 31 posts are in two threads focusing on the salvation of the SL2000 tweeter which he claims to have none:rolleyes:
    Ben
    Please. Please contact me a ben62670 @ yahoo.com. Make sure to include who you are, and you are from Polk so I don't delete your email. Also I am now physically unable to work on any projects. If you need help let these guys know. There are many people who will help if you let them know where you are.
    Thanks
    Ben
    · Share on FacebookShare on Twitter
  • mhardy6647
    mhardy6647 Posts: 33,970
    edited June 2008
    Unfortunately I don't a SL2000 tweeter of my own...
    You wouldn't say "unfortunately" if you did have one ;-)
    · Share on FacebookShare on Twitter
  • hearingimpared
    hearingimpared Posts: 21,136
    edited June 2008
    Carl is "daifanshi" your new alias?
    · Share on FacebookShare on Twitter
  • Systems
    Systems Posts: 14,873
    edited June 2008
    hearingimpared wrote: »
    Carl is "daifanshi" your new alias?
    The knowledge of certain technical details is a dead give away that they are not the same poster.
    Testing
    Testing
    Testing
    · Share on FacebookShare on Twitter
  • madmax
    madmax Posts: 12,434
    edited June 2008
    At some point I saw response curves of the sda crossovers and it looked to me that the crossovers produced the peak rather than the drivers. I will say the replacement tweeters sound better, just not sure it is because of this peak. The capacitor modification may have some merit but it has not been proven.
    madmax
    Vinyl, the final frontier...

    Avantgarde horns, 300b tubes, thats the kinda crap I want... :D
    · Share on FacebookShare on Twitter