I have an SDA2 problem guys/girls
tedturna
Posts: 2
Polk experts/enthusiasts-
today i went to a few pawn shops in the area, for browsing purposes. ive always been interested in acquiring superior audio gear, so when i first saw the SDA2's, it seemed they were something extraordinary. i went home, researched them, and was really impressed... so impressed that i went back to the pawn shop, and asked to test them. the guy said they had no means of testing, but i could buy them and return them within 30 days no questions asked. he knocked 20 bucks off the price too, making them 100 bucks plus tax. the whole ride home, i was thinking that there's no way these speakers should be this cheap; surely the person who owned them would not hock them for under $100.
essentially, i was right. i hooked them up to my roommates receiver, and one speaker works pretty well, and the other is a bit muddy. i figure i have 30 days to try and fix it, and i took some of the drivers out to see if there was a loose connection. the same midrange and tweeter on each speaker does not work at all, and on top of that one whole speaker lacks the clarity that the other has. also, i was a bit confused by the "subwoofer" (the largest driver)....when i took it out, it was not connected to anything, and was nothing more than a styrophone cone. maybe i am unaware of the reason for this, but conventional wisdom leads me to believe that an actual speaker would work better than a non powered one.
to get to the point (and i thank you for reading this far), i really thought this purchase could've been a diamond in the rough, and i dont want to let these go right away. i figure i have 29 days to get them straightened out, otherwise i can return them and get my money back. im not sure if i should take them to a hifi store that might be able to run a diagnostic test, or maybe the attempt isnt worth it. any suggestions of things i could either try or not waste my time/money on would be greatly appreciated. thanks a lot for paying attention to this; i hope someday ill have the capability of answering questions like this.
Ted
today i went to a few pawn shops in the area, for browsing purposes. ive always been interested in acquiring superior audio gear, so when i first saw the SDA2's, it seemed they were something extraordinary. i went home, researched them, and was really impressed... so impressed that i went back to the pawn shop, and asked to test them. the guy said they had no means of testing, but i could buy them and return them within 30 days no questions asked. he knocked 20 bucks off the price too, making them 100 bucks plus tax. the whole ride home, i was thinking that there's no way these speakers should be this cheap; surely the person who owned them would not hock them for under $100.
essentially, i was right. i hooked them up to my roommates receiver, and one speaker works pretty well, and the other is a bit muddy. i figure i have 30 days to try and fix it, and i took some of the drivers out to see if there was a loose connection. the same midrange and tweeter on each speaker does not work at all, and on top of that one whole speaker lacks the clarity that the other has. also, i was a bit confused by the "subwoofer" (the largest driver)....when i took it out, it was not connected to anything, and was nothing more than a styrophone cone. maybe i am unaware of the reason for this, but conventional wisdom leads me to believe that an actual speaker would work better than a non powered one.
to get to the point (and i thank you for reading this far), i really thought this purchase could've been a diamond in the rough, and i dont want to let these go right away. i figure i have 29 days to get them straightened out, otherwise i can return them and get my money back. im not sure if i should take them to a hifi store that might be able to run a diagnostic test, or maybe the attempt isnt worth it. any suggestions of things i could either try or not waste my time/money on would be greatly appreciated. thanks a lot for paying attention to this; i hope someday ill have the capability of answering questions like this.
Ted
Post edited by tedturna on
Comments
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I'm pretty sure the large woofer that was not hooked to anything is suppossed to be that way...it is called a passive radiator, and works with the energy from the 6.5" drivers for your low end. Check on e-bay or call Polk service and parts to see if you can get replacements for the blown drivers (first take the know good drivers from the other speaker and test them in the defective one to make sure it isn't the crossover that is dead). If its only a couple of speakers and you can replace them, I would say you got a good deal as long as the cabinets are in OK condition.
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The SDAs are comprised of tweeters, mid-bass drivers, and
sub bass passive (non-powered) radiators.
They're essentially 2-way speakers with an acoustically-coupled
(passive) sub bass radiator. The sub bass radiator takes over
where the smaller mid-basses leave off. Probably below 50 Hz
(?). Essentially, most of the acoustical output below that point
comes from the radiator, and not the powered drivers.
It would be a mistake---assuming the speakers are functioning
properly---to replace the sub bass radiator with an active driver
and altering the crossover circuitry to accomodate the new
configuration. Even the smaller SDAs reach into the 30-35 Hz.
region without much problem--especially when backed up
against a wall, as designed to be. If you need more extension
that that, I'd add a subwoofer for the bottom octave. If you need
more "punch" in the bass region, without much
extension---again, I'd add a subwoofer.
There should be a cable that runs between the left and right
cabinets to carry the SDA signal. This signal is, as I understand
it, a difference-signal between the L and R channels, and should
add spacialness to the sound. The SDA signal is going to be
much lower in level than the main signal, and will usually contain
less highs. For this reason, sound from some of the drivers WILL
sound muddy compared to the others. However, one cabinet
should not sound muddier than the other.
I believe the SDA drivers are going to be the outside drivers in
both cabinets, with the main signal driving the inside drivers.
Polk came out with many versions of the SDAs, with varying
numbers of mid-bass drivers and tweeters.
Since you mention that the same drivers in both cabinets are not
working, it sounds like you're missing the SDA cable that is
supposed to run between them to feed that signal. I believe you
can make that cable yourself, but someone else here can help
with that info.
If you can get the SDA effect to work, I'd say they're well worth
hanging onto. I've been using mine for 17 years, and haven't
had to do a thing to them besides replace a tweeter about
16 years ago.
Give War A Chance -
Welcome to the forum.
Did you get the SDA interconnect cable? It is a 20' long black cable that you plug into the small round hole on the binding post plate. If you didn't get it you can still purchase it from Polk, it's called the twin blade type and I believe it costs about $35.00. While you are ordering that ask Ken Swauger to send you the SDA test procedure booklet.
By what you have described I believe part of the problem you're having is that you don't have the SDA interconnect cable. It also sounds like the one speaker that lacks clarity has blown the other tweeter. It this point in time try swapping the two tweeters in that cabinet and see if that doesn't restore clarity, let me know what happens. You didn't get ripped off, the "subwoofer" is actually called a passive radiator and as such doesn't have any wires running to it. It's design is the best of both a sealed design and a ported design.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 -
Ted,
I have limited experience with the sda series, but perhaps I can be of some help anyway. I once came across a pair without the interconnect cable included and the problem you describe seems identical to what I experienced. I know this is exactly what everyone else is saying but I will continue anyway; please hear me out. After listening to the speakers at full tilt for nearly 48 hours they began to really warm up and sound better. What I later discovered was that while this interconnect cable rectified my problem, I was still not hearing the full potential of the speakers. A friend bought them off me and he continued to fiddle with them. When he took them to a local hi-fi repair shop they told him that the mid-bass driver he was having trouble with was not blown, but rather muffled due to problems within the crossover in the cabinet. Long story short, the tech made a quick ($15) capacitor replacement and my friend left with a pair of sda2s in perfect condition that he got off me for 100 bucks plus 15 for the generic part. I dont know if this is your problem... but I sure hope it is. -
Ted, first, welcome to the forum and congratulations on your find.
Second, call Ken Swaugger, Polk CS, ASAP and request a copy of the SDA troubleshooting guide. He'll send it to you free of charge.
The guide is a series of Volt-Ohm Meter (VOM) checks with various connections made and not made. It takes some time to complete the check out, but the individual steps are straightforward.
An SDA IC is needed to do the tests, but you can quickly rig one for test purposes. Ken, can guide you here as well.
Do note that the amp/ receiver you are using needs to be a common ground design for the plain wire SDA IC to be acceptable. Otherwise you will need a special IC such as har is selling here:
http://clubpolk.polkaudio.com/forum/showthread.php?s=&threadid=12953More later,
Tour...
Vox Copuli
Better to remain silent and be thought a fool, than to open your mouth and remove all doubt. - Old English Proverb
"Death doesn't come with a Uhaul." - Dennis Gardner
"It's easy to get lost in price vs performance vs ego vs illusion." - doro
"There is a certain entertainment value in ripping the occaisonal (sic) buttmunch..." - TroyD -
please explain this common ground concept. Im totally in the dark as to what that means
