Sda-2 have very little bass

sansuibutch
sansuibutch Posts: 190
edited March 9 in Vintage Speakers
I picked up a set of the original sda-2. The ones with 3 mw's and 2 tweeters in each. They sound horrible. Im not sure if somthing is wrong with them or thats just how they are. Placment is not perfect as they are in front of my setup but ive listened to a ton of speakers in this same position and have never heard any like this. The seals are the best ive ever seen, if you hold the pr in the 3 mids will stay out as long as you hold it (well over a minute at the least thats about how long i held it). All drivers seem to be working. When doing the battery test i get two midwoofers pushing out and the sda midwoofer pulling in from the vacume. Im not sure how to test phase of the sda mw. The drivers dont look like they have ever been removed before, i pulled all 3 of them from one cabinet and they are all mw6600x. Ive never seen one of these mw. I know these are not a great example of sda's but there is no way they left the factory this bad. I guess i can test some capacitors in the xover but somthing just doesn't seem right. They sound very bright, but mainly because there is harldy any bass. I ran a a bunch of test tones and they move a lot just very little low end output. When playing it seems like when i disconnect the ic the speakers do make a little more low end (wich seems right to me as the sda driver is out of phase with the other channel wich is close in signal) does this sound familar to anyone. I didnt see any glue on the magnets of the drivers i pulled so dont think the magnets were glued on backwards. Also the 2 cabinets make more bass than one and i reversed the leads on one speaker and the bass was even less so im pretty sure the cabinets themselves are in phase. Any help would be awsome.
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Comments

  • sansuibutch
    sansuibutch Posts: 190
    The amp is definitely common ground as ive tested it with a dmm and it has ran my sda srs flawlessly
  • F1nut
    F1nut Posts: 46,296
    When doing the battery test i get two midwoofers pushing out and the sda midwoofer pulling in from the vacume.

    You have drivers wired out of phase. Look at the schematic posted here.

    Wiring code:
    Blue or black is positive
    White or green is negative
    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

  • sansuibutch
    sansuibutch Posts: 190
    F1nut wrote: »
    When doing the battery test i get two midwoofers pushing out and the sda midwoofer pulling in from the vacume.

    You have drivers wired out of phase. Look at the schematic posted here.

    Wiring code:
    Blue or black is positive
    White or green is negative

    ^^^ this is how they are currently connected. The inly reason the sda mw is pulling in is becsuse the vacume from the 2 drivers pushing out (it doesnt seem to see the battery power). I though that was weird as my big polks iirc they all move the same way when touching a 9v battery to the binding posts. But when i looked at the schematic of these it seems the sda mw shouldnt be powered from the battery test. Does that make sense?
  • BlueFox
    BlueFox Posts: 14,795
    Maybe you are hearing the music as recorded. Good speakers neither add or subtract anything to the music.
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  • sansuibutch
    sansuibutch Posts: 190
    Thats not it. I have had over 50 sets of very nice speakers and these are clearly very difficult to listen to. My 5jrs sound way more balanced and still put out more low end. I was thinking they might just depend on that wall more than i could imagine. I wouldnt think they would be better enough against the wall to be able to blame it on that. This is very strange for sure. Even with the ic cable unhooked the four stereo woofers are all in phase and moving good but still no low end. Even the midbass is allmost non existent.
  • sansuibutch
    sansuibutch Posts: 190
    I did just move them back a couple feet and it made a huge difference. They are still three feet off the wall tho. Could it just be that these speakers rely more on the front wall/room than most speakers?
  • audioluvr
    audioluvr Posts: 3,720
    Not sure but they like about 6" from the back wall and at least a couple feet or more from the sides. I had SDA2b's a long time ago and I remember them having earth shaking bass so hope you get them figured out.
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  • sansuibutch
    sansuibutch Posts: 190
    audioluvr wrote: »
    Not sure but they like about 6" from the back wall and at least a couple feet or more from the sides. I had SDA2b's a long time ago and I remember them having earth shaking bass so hope you get them figured out.

    Im really thinking they just need that wall. It is strange that closer to the middle of the room they sound completely lifeless. Just a couple feet has them sounding worlds better. Even my 5jr and monitor 4 seem to perform perfectly fine even in the middle of the room. I do remember my sda srs being pretty time consuming to get placed right, they seem to like the wall also now that i think about it.
  • audioluvr
    audioluvr Posts: 3,720
    Pics help too in evaluating your listening environment.
    Cambridge Audio 851N Streamer/DAC
    Belles 21A Pre modded with Mundorf Supreme caps
    B&K M200 Sonata monoblocks refreshed and upgraded
    Belles 350A Reference modded with Mundorf Supreme caps
    Polk SDA 1C's modded / 1000Va Dreadnaught
    Wireworld Silver Eclipse IC's and speaker cables


    There is about a 5% genetic difference between apes and men …but that difference is the difference between throwing your own poo when you are annoyed …and Einstein, Shakespeare and Miss January.

    by Dr. Sardonicus
  • F1nut
    F1nut Posts: 46,296
    I did just move them back a couple feet and it made a huge difference. They are still three feet off the wall tho. Could it just be that these speakers rely more on the front wall/room than most speakers?

    They have to be 5 to 6 inches off the wall.

    The SDA driver has to move in phase with the stereo drivers. Only the PR is out of phase.
    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

  • sansuibutch
    sansuibutch Posts: 190
    Okay i havnt technically checked polarity of the sda mw's (besides the color of wired connected to them). Later il plug in the ic and pull the tweeter fuses and hook a single 9v battery to both sets of speakers at the same time to find out if all the midwoofers move in the same direction.
  • gmcman
    gmcman Posts: 1,636
    Okay i havnt technically checked polarity of the sda mw's (besides the color of wired connected to them). Later il plug in the ic and pull the tweeter fuses and hook a single 9v battery to both sets of speakers at the same time to find out if all the midwoofers move in the same direction.

    Please use a 1.5V battery. I don't know with 100% certainty if any dangers exist with using a 9V but not worth the risk.

    That will be PLENTY to extend all the drivers. Like stated before, ALL the mid drivers should extend except for the passive.
  • sansuibutch
    sansuibutch Posts: 190
    No problem using a 9v. I used one last night (after removing the tweeter fuses) on each individual cabinet. I just connect it for a very short duration as we all know voice coils dont like dc. Hooking both cabinets to the same 9v for a very short duration wont hurt anything.
  • sansuibutch
    sansuibutch Posts: 190
    Ok so i left the ic connected to both speakers and when i connect the 9 volt battery the drivers move like they are supposed to besides the sda mw's. I know the ic is getting a good connection because when i touch the ic to the battery just the sda woofer move. Mmm very weird. Same result on both cabinets.
  • Gardenstater
    Gardenstater Posts: 2,028
    edited March 10
    I would suggest pulling each SDA driver out of the cabinet one by one, and checking momentarily with the 9V battery, with the wiring disconnected. Aside from that, have you run the checks in the manual on p. 5 for your speakers and have you tested the resistances according to the SDA Manual?

    https://www.hifiengine.com/manual_library/polk-audio/sda-2.shtml

    https://us.v-cdn.net/5021930/uploads/editor/fe/zg3wih4m7prz.pdf
    George / NJ

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  • sansuibutch
    sansuibutch Posts: 190
    I did check dcr at binding posts. One was 5.1 and one was 5.3. Not really out far enough tp worry me.
  • Gardenstater
    Gardenstater Posts: 2,028
    kgdlnt8412de.jpg

    mwwr2knu7s0k.jpg

    George / NJ

    Polk 7B main speakers, std. mods+ (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Crown D150 amp
    Logitech Squeezebox Touch Streamer w/EDO applet
    iFi nano iDSD DAC
    iPurifier3
    iDefender w/ iPower PS
    Custom Steve Wilson 1m UPOCC Interconnect
    iFi Mercury 0.5m OFHC continuous cast copper USB cable
    Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
    Custom Vibration Isolation Speaker Stands and Sub Platform
  • sansuibutch
    sansuibutch Posts: 190
    kgdlnt8412de.jpg

    mwwr2knu7s0k.jpg

    Oh i definitely didnt see this. Il check those now. Thank you very much for that.
  • Gardenstater
    Gardenstater Posts: 2,028
    m4qrcf3s515l.jpg
    George / NJ

    Polk 7B main speakers, std. mods+ (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Crown D150 amp
    Logitech Squeezebox Touch Streamer w/EDO applet
    iFi nano iDSD DAC
    iPurifier3
    iDefender w/ iPower PS
    Custom Steve Wilson 1m UPOCC Interconnect
    iFi Mercury 0.5m OFHC continuous cast copper USB cable
    Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
    Custom Vibration Isolation Speaker Stands and Sub Platform
  • Gardenstater
    Gardenstater Posts: 2,028
    ydj6zr4s25c4.jpg

    7xe40v0dc7j6.jpg
    George / NJ

    Polk 7B main speakers, std. mods+ (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Crown D150 amp
    Logitech Squeezebox Touch Streamer w/EDO applet
    iFi nano iDSD DAC
    iPurifier3
    iDefender w/ iPower PS
    Custom Steve Wilson 1m UPOCC Interconnect
    iFi Mercury 0.5m OFHC continuous cast copper USB cable
    Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
    Custom Vibration Isolation Speaker Stands and Sub Platform
  • sansuibutch
    sansuibutch Posts: 190
    I check all those resistance measurments. They are way closer than i thought theyd be, all within .1 ohms. Anyway im starting to think nothing is wrong with them and placement is much more critical than most speakers. I have both of them in one side of the room with ther backs to me. After taking ohm readings i hooked then up right were they are and they putt out a ton of bass even at low volume and had no problem filling the room. Ive never owned a set of speakers that sounded better facing away from me ahahhah. I just think they are more room/placement dependent than i thought was even possible. I will really have to get them setup half way decent and give them a try. I dont think the harsh sounding tweeters will get smoother but will likely way more balenced.
  • sansuibutch
    sansuibutch Posts: 190
    m65gud51a9li.jpg

    Here is my room. I had them placed right in front of my big polks. And i get the sda srs behind them might eat up all the low end that would normally radiate out around the cabinet but most speakers setup there sound full and fine. These are just empty sounding placed there, Allmost like just tweeters. My sda srs took me a while to place and them big tyler acoustics in the corners are 250lbs a piece. So il have to find another wall ahahha.
  • sansuibutch
    sansuibutch Posts: 190
    edited March 10
    This just gets weirder and weirder. So i set the speakers back to where i had them and now they sound like they should. A night and day difference. Im not sure if the 9v batter woke something up or what. The sda cable fits very tight and definitely was not the issue as i swept from left to right with the balance to make sure the sda drivers were working last night. Im also positive i had the left and right cabinets on the proper side. Im more confused now then when i first wired them up ahahhah. Idk .
  • TennMan
    TennMan Posts: 1,147
    m65gud51a9li.jpg

    Here is my room. I had them placed right in front of my big polks. And i get the sda srs behind them might eat up all the low end that would normally radiate out around the cabinet but most speakers setup there sound full and fine. These are just empty sounding placed there, Allmost like just tweeters. My sda srs took me a while to place and them big tyler acoustics in the corners are 250lbs a piece. So il have to find another wall ahahha.

    When I look at your photo of the room it's pretty obvious why you don't feel much bass from the SDA 2s. Each time the MWs are pushed out to to pressurize the room to produce a deep bass note, all the 30+ drivers in those other speakers are being pushed in and absorb the pressure produced by the SDA 2's MWs.
    • SDA 2BTL · Sonicaps · Mills resistors · RDO-198s · New gaskets · H-nuts · Erse inductors · BH5 · Dynamat
    • Crossover upgrades by westmassguy
    • Marantz 1504 AVR (front speaker pre-outs to Adcom 555)
    • Adcom GFA-555 amp · Upgrades & speaker protection added by OldmanSRS
    • Pioneer DV-610AV DVD/CD player
    • SDA CRS+ · Hidden away in the closet
  • sansuibutch
    sansuibutch Posts: 190
    TennMan wrote: »
    m65gud51a9li.jpg

    Here is my room. I had them placed right in front of my big polks. And i get the sda srs behind them might eat up all the low end that would normally radiate out around the cabinet but most speakers setup there sound full and fine. These are just empty sounding placed there, Allmost like just tweeters. My sda srs took me a while to place and them big tyler acoustics in the corners are 250lbs a piece. So il have to find another wall ahahha.

    When I look at your photo of the room it's pretty obvious why you don't feel much bass from the SDA 2s. Each time the MWs are pushed out to to pressurize the room to produce a deep bass note, all the 30+ drivers in those other speakers are being pushed in and absorb the pressure produced by the SDA 2's MWs.

    I understand exactly what your saying. But i have placed many speakers in the same exact spot and you would be surprised how much low end they still produce. Also there is prolly 20 more speakers in this room just not up front. Either way now they sound very good and have no problem pressurizing the room. Im not sure wth was going on but im not disappointed. Now i can unhook that one tweeter and see if they get better. They sound a lot bettter then the stuff i read about them made out to be. They are still little bright. But the sound just has body now. Somthing has changed and its going to drive me nuts not knowing. Maybe it will happen agian and il have to investigate.
  • TennMan
    TennMan Posts: 1,147
    I understand exactly what your saying. But i have placed many speakers in the same exact spot and you would be surprised how much low end they still produce. Also there is prolly 20 more speakers in this room just not up front. Either way now they sound very good and have no problem pressurizing the room. Im not sure wth was going on but im not disappointed. Now i can unhook that one tweeter and see if they get better. They sound a lot bettter then the stuff i read about them made out to be. They are still little bright. But the sound just has body now. Somthing has changed and its going to drive me nuts not knowing. Maybe it will happen agian and il have to investigate.
    Of those other speakers that produced good low end bass in that room, how many of them only had two 6-1/2" drivers in each cabinet to produce the bass?

    • SDA 2BTL · Sonicaps · Mills resistors · RDO-198s · New gaskets · H-nuts · Erse inductors · BH5 · Dynamat
    • Crossover upgrades by westmassguy
    • Marantz 1504 AVR (front speaker pre-outs to Adcom 555)
    • Adcom GFA-555 amp · Upgrades & speaker protection added by OldmanSRS
    • Pioneer DV-610AV DVD/CD player
    • SDA CRS+ · Hidden away in the closet
  • sansuibutch
    sansuibutch Posts: 190
    edited March 10
    TennMan wrote: »
    I understand exactly what your saying. But i have placed many speakers in the same exact spot and you would be surprised how much low end they still produce. Also there is prolly 20 more speakers in this room just not up front. Either way now they sound very good and have no problem pressurizing the room. Im not sure wth was going on but im not disappointed. Now i can unhook that one tweeter and see if they get better. They sound a lot bettter then the stuff i read about them made out to be. They are still little bright. But the sound just has body now. Somthing has changed and its going to drive me nuts not knowing. Maybe it will happen agian and il have to investigate.
    Of those other speakers that produced good low end bass in that room, how many of them only had two 6-1/2" drivers in each cabinet to produce the bass?

    Yesterday my 5jr and monitor 4 absolutely put these sda 2 to shame. Somthing was wrong. Oh and these have three 6-1/2" drivers with a pr. I have listened to prolly at least 100 different speakers placed in the same spot and never heard a set fall on there face like that
  • sansuibutch
    sansuibutch Posts: 190
    I aquired these speakers from a friend. I was at his place yesterday and we listened to around seven different pairs of speakers. The last ones we hooked up were these polks and they sounded like a loud pair of headphones, just terrible. I figured maybe we had them too far off the wall at his house (or somthing as there is no way they sound like this) . I then brought them to my house and they sounded the same way (Terrible) . They are a completely different speaker now and thats very strange as i havent done anything to them besides dissect them a little.