Why did Polk abandon the SDA approach?

William Henry

If they were so good, why did they stop making the SDA line?

hoosier21

there is no good answer to that.

DarqueKnight

Great answer.:)

nadams

Well thought-out reply, Zero. I think it explains things very well.

BigJim

Very well said...

Emlyn

I don't agree that there was a link between Polk's halting of production of SDA two-channel speakers and the move to Circuit City, because the move away from independent dealers to Circuit City happened several years after Polk stopped making the SDA speaker line in Baltimore.

I do agree that the home entertainment market changed and Polk Audio had to change to keep afloat. Some audio companies were not forward thinking enough and went bankrupt, or merged into larger companies, during and right after the recession of the early 1990s. Considering the price Polk sold its most expensive speaker line at, and the amount it must have cost to produce them in Baltimore, it's not surprising that production stopped for simple business reasons. Polk's production costs became too high relative to the customer's willingness to spend money on SDA speakers. Many companies have had to face the harsh realities of the global economy by moving production to Mexico, then to Asia to remain competitive, while adjusting products to be able to hold a place in their market. Polk now makes speakers in the middle to upper-middle of the market. SDA speakers really were competing at the upper end of the market when they were last produced, and the company decided to get out of that market segment and head in a different direction. There is no question of "if they were so good"; SDA true stereo speakers were and remain excellent speakers more than a decade after production stopped.

Polk embraced the move to home theater surround speaker systems (for which SDA technology is not necessary) comparatively early, and the big move around 1998 to Circuit City enabled Polk to thrive by selling many more speakers than they ever had before. The upper-middle market LS speaker line did not survive this transition, but the LSi line is a successful attempt to get back into the upper-middle section of the market. Polk doesn't produce SDAs now because the company doesn't compete for the audiophile two-channel market along with high-end product lines from companies like B&W, Martin Logan, Spendor, Dynaudio, Magnepan, or a whole slew of smaller companies. However, Polk speakers now offer a good budget-conscious, honest performance alternative to the expensive offerings from these companies.

Fortunately, Polk built their SDA speakers to last a long time. Mine will celebrate their 20th birthday this November.

AsSiMiLaTeD

All good discussion...

and let's not forget the fact that many people simply don't want huge speakers intruding in their living space, as crazy as that may sound...though I'm sure an SDA could be made to fit in a smaller enclosure...

DarqueKnight

Originally posted by William Henry
If they were so good, why did they stop making the SDA line?

This is a frequent question about the SDA series. It seems that people often assume that something had to be "wrong" with the SDA series, hence, their discontinuance. SDA's were manufactured over a period of nine years (1982-1991). This is an exceptionally long time for an audio product. All products, no matter how "good" they are, are eventually discontinued. Times change, consumer's tastes change, markets change. Companies that can not or will not adapt to those changes usually go out of business.

Truly bad products are usually quickly put out of production and quickly forgotten (abandoned) by consumers. Truly good and/or exceptional products frequently become "classics" after their formal manufacturing run is over.

A strong testament to the quality and desirability (or "goodness") of the SDA series is the fact that a brisk trade in these speakers still exists 23 years after their market introduction and 14 years after they ceased production. Polk Audio has not "abandoned" the SDA series. They still provide parts and customer support for this line. Even more than that, they continue to provide improved replacement parts for this series (e.g. improved polyswitch, improved tweeters, etc.).

While I can not reasonably expect Polk to reintroduce the SDA line, I would like to see them expand their replacement parts program to include improved drivers and crossovers.

William Henry

Thanks for all the responses on the Polk SDA.

I did not know about tweeter update/replacements. What is the tweeter and how is it better?

Anyway to get new grills? A Xmas candle overflowed and sent streaks down the front of one grill. I was going to replace the grill cloth until I saw it was fastened with 3 zillion staples.

Thanks, SDA lovers!

DarqueKnight

You are going to have to remove the 3 million staples and stretch new grille cloth on the frame.

The replacement for the SL2000 is the RD-0194-1. The replacement for the SL3000 is the RD-0198-1. You can find a lot of information about these tweeters by doing a forum search on the part numbers.

Strong Bad

Originally posted by Polkmaniac
All good discussion...

and let's not forget the fact that many people simply don't want huge speakers intruding in their living space, as crazy as that may sound...though I'm sure an SDA could be made to fit in a smaller enclosure...

Also, in order for the SDA Effect to work properly and to it's fullest, a certain amount of space has to be made available for them. You can't just stick them anywhere convenient.

Why is bose so successful at selling their junk? Great marketing of small cubes that can be put almost anywhere, then hide the bass box behind a couch.

I think the SDA's physical size and space requirements were the biggest one-two punch of their downfall.


John

William Henry

I have a large a-frame room with west side all glass windows.

Many a day I have thought of a subwoofer...

Any suggetions.

SDA2 machines.

F1nut

I disagree with the size issue. There are plenty of LARGE high end speakers still made today and people still buy them. Polk Audio decided to go a different direction and is making a killing by doing so. It is a shame they gave up the high end market though.

Strong Bad

How dare you disagree with me!!!



John

William Henry

I have often felt my
SDAs were absorbed in bass ....I think it may be the room.

Suggestions about subwolfs?

F1nut

I had to write a big check to Uncle Sam today, so I'm in a general disagreeable mood.

F1nut

If you have enough bass from your SDA's why do you want a sub?

William Henry

I think the issue is the size of the room vs SDA output.

Strong Bad

Originally posted by F1nut
I had to write a big check to Uncle Sam today, so I'm in a general disagreeable mood.

Uncle Sam got some from me too, but I have a sneaking suspicion that I didn't get raped nearly as bad as you.

Be walking funny for a while, ehh Jesse!


John

Larry Chanin

Originally posted by john d. strong
Also, in order for the SDA Effect to work properly and to it's fullest, a certain amount of space has to be made available for them. You can't just stick them anywhere convenient.

Why is bose so successful at selling their junk? Great marketing of small cubes that can be put almost anywhere, then hide the bass box behind a couch.

I think the SDA's physical size and space requirements were the biggest one-two punch of their downfall.


John

Hi John,

Yes, I agree that the SDA effect requires a cabinet no narrower than about a foot.

I also agree that nowadays there is a large market segment, especially in the mass market versus high-end market, that favors a small foot print.

And finally I also agree that this, coupled with the added costs of multple SDA drivers, helped to phase out the SDA's in the past.

However, there is a new development in Polk Audio's marketing strategy. Polk Audio has begun to enter into the Custom Installation market with their new line of In-Wall speakers and subwoofers. Therefore, in theory it is possible to design a new line of In-Wall SDA's in which size is not a factor.

I know that, as the name suggests, Stereo Dimensional Arrays were originally designed for two channel stereo sound. Nevertheless, as was demonstrated by the Signature Reference Theater version of the SDA's, the improved imaging of the SDA effect is not unwelcome in a home theater environment.

So whereas it might not be easy, it is possible in theory at least, to introduce a line of In-Wall SDA's with unparalleled imaging, which would appeal to the mid to high-end custom installation market, while circumventing the current aversion to large speakers.

Larry

PolkFreak

I would like to elaborate to the good points that have been made.
The following statements within this list will not be in any order.


1. The mainstream doesn't like huge bulky speakers and would rather have a skinny Popsicles tower for a home theater speaker. They think it looks better :cool:


The above reason is a big reason to follow this "trend" and start making skinny skeleton speakers that look like they are in need of some beef. To survive in the market and make money you have to change along with peoples needs and wants. The mainstream wants smaller speakers and Polk needs to make what the majority wants. A small number of us love our dinosaur sized speakers, but the big money is with appealing to larger groups. The bigger the group the larger the Pyle of money gets. More customers more money. If Polk still made big speakers they would have a small fan base and wouldn't have enough money to
stay in business. OK on to the next point because I've made the same point over and over, but just said it different


2. 5.1 surround is the "in" thing these days. The SDA is designed for 2 channel stereo. The mainstream could care less about having to sit in the SDA sweet spot. For some reason 5.1 surround has been crowned king of realism. People seem to think it is possible for a more realistic sound environment, but does a concert surround the listener like it does on 5.1 channel music cd? Add in the verity of ways the producer or whoever can put together the sound and it sounds even farther from realistic. Yes, this is my opinion, but a lot 2 channel listeners can agree. The performers are in front of the people they are playing for. Ya, you could have the rears do the screaming fans behind you, but those are the same people I want to choke or stuff a pair of gym socks in their mouth at a live event:mad: I do know that if 5.1 is used correctly it could sound O.K., but not as good as the SDA effect IMO.


Getting back to the fact that the SDAs were designed for 2 channel. I have heard people ask if they should have the SDA cable on or off for movies. Yes the SDA effect cancels crosstalk and
the sound is more separated between the two speakers, but the SDA sound stage wasn't designed to have rears speakers factored in the equation. The SDA sound wraps around the listener and when running in 2 channel with a music cd in a 5.1 setup you might be finding yourself putting your ear next to the rear speaker to see if it is running. The SDA sound stage is deep and having the rears running only interferes with the SDA sound stage and makes it sound like crap. To see what I mean put in a standard PCM cd that really shows off the SDA effect. Listen to it in two channel with the SDA cable in place. Now put your AVR to all channel stereo with the SDA cable still on. Now the rears are putting out the same music the mains are and it sounds like crap and you can see how bad it messes with the SDA sound stage. Realistically you wouldn't have that sound at a live event. It sounds really bad not to mention that all channel stereo was meant for background noise. The center channel makes music sound like crap as well and interferes with sound stage really bad as well. It smears the sound of the main left and right speakers. It destroys the separation between the main speakers. The sound tends to blur together. It also messes with the imaging of the 2 speakers. These are all my opinions and people are entitled to disagree if they want. So these are the reasons I take my SDA cable off for 5.1 channel home theater. That lets me use my SDAs as a regular, "stereo" speaker that would work in the same way todays NON-SDA speakers work for home theater. 5.1 channel sound may be crap for music to me, but on the other hand it works very well for movies. To me 5.1 is realistic for movies and has no problem putting me in the middle of the action. I only use my center channel for movies the way I think it should be. I should also mention that the SDA cable washes out the bass because the inner 6.5 inch mid/bass driver
on both SDA speakers is used for bass only and the outer drivers
on each speaker is used for midrange when the SDA cable is in place. Without the SDA cable all of the 6.5 inch mid/bass drivers do midrange and bass. My speakers also seem to be tougher without the SDA cable. I can turn them up louder on say rap music. Even though I'm not much of a fan of that type of music.


So 5.1 surround and smaller, "better" looking speakers as well as people that don't give two **** about good sound and want background noise at their dull lifeless parties. These people also make up the majority that we call the mainstream out number the
small number of people that like Hi-REZ sound formats and good sounding speakers that are the size of a commercial refrigerator.
Polk also directs their speaker design/cost ratio much of the same way. More people are willing to buy a mass produced speaker that has the same or better sound quality than one that is custom
built and super expensive. When the price point is out of reach to the majority less people will buy it in turn the company makes less money. I would also like to note that the last SDA Polk speaker I saw was in their year 2000 catalog which had 5.25 inch
drivers instead of the classic 6.5 inch drivers on the 80's Polks. These SDAs were in SRT home theater package aka The Signature Reference Theater system. These SDAs also had powered subs with the power port design. I think these are pretty rare because it was an expensive speaker package. I still own the 2000 catalog. I have been seeing people state that 1991 was the last year they made the SDA. It was the last year for the classic SDA. I just noticed how huge this post is.


If you made it to this point this post didn't make you fall asleep and your lucky you didn't:D I also felt I had to explain how
the SDA technology works for those who didn't know or didn't get a clear answer. I bounced around a lot, but thats ok I guess.

I also forgot to mention that I too like others on the forum think
that live concerts sound like crap. Every instrument in a live concert seems to break the sound barrier. Well, this is true for the Perfect Circle concert I went to anyway. Everything was distorted and the output of the sound system was too much for that little building. None of the instruments were balanced. I'll also have to add that a live concert can't compare to the smooth
balanced rich sound of a pair of Polk SDAs IMO. I think the SDAs sound better than those big speakers they have at concerts, but things aren't always the same. Some bands might have a really good set of concert speakers that have quality sound worth hearing, but I'd still rather listen to my SDAs. Their sound quality is unique and is something that I've only heard on them.

danger boy

Originally posted by Polkmaniac
All good discussion...

and let's not forget the fact that many people simply don't want huge speakers intruding in their living space, as crazy as that may sound...though I'm sure an SDA could be made to fit in a smaller enclosure...

that's just crazy talk....

think of it this way.... during the production years of all models of the SDA line of speakers.. does anyone really know how many pairs of SDA's were even sold?
hundreds? thousands?

So as i see it.. they were quite popular in their day.. but like everyone else has said.. times change. Some people I'm sure would not want two 155 lbs large speakers in their living room. Plus the cost of the time was probably quite expensive.

The used prices we all are buying them at now.. is way below what people were paying for them back then. Most of us are getting SDA's in the range of $200 - $800. that were orig cost $800 to $3000.

HOw many of us could plunk down close to $3000 for a pair of SDA's back 20 yrs ago? Now that same pair is going for $800. See the difference? New vs used prices.

that's my story and i'm sticking with it.

jcmccorm

Polkfreak, interesting.

I leave the IC cable (SDA cable) installed all of the time; movies, multi-channel music, and 2 channel music. Of course for movies, not everyone is in the sweet spot, but I haven't noticed any problems with that.

For multichannel music, it's almost always just me listening and I am in the sweet spot. Keeping the SDA cable installed hasn't been a problem. I am curious as to why you think the SDA effect is a bad thing for multichannel music.

I'm also curious about your statement regarding the SDA cable washing out the bass. Are you saying it changes the frequency/SPL curve in the lower frequencies? (reduces volume of the bass at some point)

I haven't experienced or heard of anyone having issues with SDA in a 5.1 environment so I'm really curious.

I will try running 2 ch music in 5 channel stereo with and without the SDA cable as you suggested.

Cary

Larry Chanin

Hi PolkFreak,

I'd like to take exception to some of your remarks.

Getting back to the fact that the SDAs were designed for 2 channel. I have heard people ask if they should have the SDA cable on or off for movies. Yes the SDA effect cancels crosstalk and the sound is more separated between the two speakers, but the SDA sound stage wasn't designed to have rears speakers factored in the equation. The SDA sound wraps around the listener and when running in 2 channel with a music cd in a 5.1 setup you might be finding yourself putting your ear next to the rear speaker to see if it is running. The SDA sound stage is deep and having the rears running only interferes with the SDA sound stage and makes it sound like crap. To see what I mean put in a standard PCM cd that really shows off the SDA effect. Listen to it in two channel with the SDA cable in place. Now put your AVR to all channel stereo with the SDA cable still on. Now the rears are putting out the same music the mains are and it sounds like crap and you can see how bad it messes with the SDA sound stage.

First, is there any harm in leaving the the SDA crosstalk cancellation on during a multichannel movie, say a Dolby Digital 5.1 presentation? It is true that SDA was originally designed for stereo and it produces out of phase cancelling signals in the SDA drivers to create crosstalk cancellation. So why should that be any different in a multichannel presentation? The main speakers are still receiving a stereo signal so the SDA drivers work as before, cancelling crosstalk in the main channels. Now if we were to play the EXACT same signals through the center and all the other surround channels, then I think perhaps a case could be made that this would interfere with the SDA presentation. However, 5.1 DISCRETE soundtracks by definition DO NOT produce the same signals in all channels.

It is true if you take two channel source material and apply a crappy surround process to it and deliberately reproduce the same signal in all channels it won't sound good. So don't do it. However, there are some excellent surround processors, i.e., Dolby ProLogic IIx and Lexicon's LOGIC7, etc., that can do an excellent job of extracting distinctly different signals from a two channel source, and still leave a good stereo signal in the mains to be used without damaging the SDA effect.

Realistically you wouldn't have that sound at a live event. It sounds really bad not to mention that all channel stereo was meant for background noise. The center channel makes music sound like crap as well and interferes with sound stage really bad as well. It smears the sound of the main left and right speakers. It destroys the separation between the main speakers. The sound tends to blur together. It also messes with the imaging of the 2 speakers. These are all my opinions and people are entitled to disagree if they want..

I agree with your previous remarks that there are a lot of multichannel music presentations in which the sound mixers have applied in appropriate sounds to the surround channels and this detracts from a realistic performance. However, that doesn't mean that ALL multichannel music presentations are poortly mixed and unrealistic. All live music venues have ambient noises surrounding the audience, some coming from the audience, but more importantly there are the unique sounds of the "Hall". These room reflections are necessary for the human ear to determine the spaciousness of the room. The art in mixing multichannel music is to apply these ambience effects realistically without detracting from the musical performance. I am not an audiophile, but some would argue that a correctly mixed multichannel soundtrack may come closer to the real thing because it is possible to precisely place the right amount of ambience effect in discrete surround channels placed behind the listeners. This permits recreating the sonic environment of the performance that tells us the size of the room.

In multichannel soundtracks the center channel is a separate discrete channel recorded apart from the main channels. It is used to help anchor the sound in the center of the soundstage by having a physical speaker located in the center. This can be done more accurately than a phantom stereo image, specially for listeners seated off-axis were the sounds erroneously shift to the nearest speaker. Another problem is comb filtering associated with stereo. Here inorder to center a phantom image we have two identical sounds (i.e, mono) coming from each main speaker. Listeners sitting off-axis will experience a delay between the two mono sounds coming from each main speaker which results in constructive and destructive reenforcement of the sound, otherwise know as comb filtering. With a center channel the mono signal is applied to a single center speaker, just as in real life. There is no second sound to interfere.

I should also mention that the SDA cable washes out the bass because the inner 6.5 inch mid/bass driver on both SDA speakers is used for bass only and the outer drivers on each speaker is used for midrange when the SDA cable is in place. Without the SDA cable all of the 6.5 inch mid/bass drivers do midrange and bass.

Perhaps some of the veteran SDS'ers can jump in here, but I though with the interconnect removed there is no means for the SDA drivers to receive a signal, consequently they are inactive.

Larry

jcmccorm

I think even I can answer the last one. I don't have my SDA Compendium here with me to check through schematics of all of the SDA's, but at least with the SRS's and 1C's (the speakers I have), if the SDA cable is left unconnected, the outside drivers are not fed any signal at all and only the inner drivers are working, so I think PolkFreak might be incorrect on that point.

Cary

DarqueKnight

If you disconnect the SDA cable and put your ear close to an SDA driver, you will hear a little output.

With the SDA cable disconnected, a very small, almost inaudible, amount of output does come from the SDA drivers, but most of this is due to the acoustic coupling between the SDA drivers and the stereo drivers. Most of the electronic signal going to the SDA array is blocked by a 16 mH inductor in series with the array. When the SDA cable is plugged in, this 16 mH inductor is bypassed and the phase reversed signal from the other speaker is sent through.

If you really want to hear what comes through the SDA drivers without the SDA cable, you would have to disconnect the tweeters and stereo drivers. Let us know what you find out.:)

jcmccorm

Thanks for correcting me Raife! I'm looking at the SRS schematics now in your compendium. I see the 16mH inductor in the return path for the SDA drivers. I knew that the SDA drivers moved without the interconnect cable but I assumed it was all due to acoustical coupling. I guess not (well, they will driven at some frequency, but it will be low due to the large inductor).

Cary

Tour2ma

Originally posted by DarqueKnight
If you really want to hear what comes through the SDA drivers without the SDA cable, you would have to disconnect the tweeters and stereo drivers. Let us know what you find out.:)

Or use the balance control, if you have one...

There's no question in my mind that the move away from the SDA and the associated attempts to compete towards the high-end of the home audio market was a strategic decision dictated by profit potential.

Polk built itself on the modest, but impressive back of the mid-line monitors. They kept reaching for higher highs (and bigger bigs) in that line adding Mon 12's and the like which morphed into the original SDA's. The TOTL kept growing in size, and cost, until the release of the SDA SRS.

With the SRS series added to the mix, Polk found itself straddling a line up with a price range from $100 a pair to a near $3500. Hard to survive operating in a niche that approximates the width of the Grand Canyon. This is the bigger issue in my mind than the size or the other issues.

Did Polk make money on the SDA’s? Sure. As much as they did on the lines that followed? Not on a percentage basis. Dropping the PR’s for ported designs alone was a significant profit margin boost.

Esthetically the bigger SDA's do dominate a room by their sheer size, but they are not so demanding placement-wise that you have to build a room around them. There are successful companies producing more demanding speakers in that regard... Magnepan comes immediately to mind. And size alone does not explain the demise of the smaller SDA's, i.e., the 3.1tl and CRS's.

My speakers also seem to be tougher without the SDA cable. I can turn them up louder on say rap music. Even though I'm not much of a fan of that type of music.

No one took this one, so I'll give it a whack... With fewer drivers in play SDA-less, you'd have to crank the volume up to match SPL levels. Not sure what dropping the SDA does to speaker impedance (if I could find my damn VOM, I’d know), but if I had to guess, I'd guess increases it which would reduce the current demands on the amp. This would give the appearance of the amp being beefier and let you crank it more. (Care to comment, Raife?)

As for SDA in HT being bad... that's not my experience. First, a qualifier... my SRS's are roughly centered and separated by 9' (center to center) on the long wall of my 21' x 15' den. In my room in 2 ch duty the SDA extends the width of the soundstage, often to the full 21'. Very seldom does it "wrap around" me. It happens, but it's rare. So I find that SDA reaches out to meet the side surrounds and creates a seamless sound field.

Years ago with my babies on the short wall of a smaller room, I experienced more “wrap-around” sound, with the occasional, “that came from behind me” experience. Maybe in that room the HT results would have been undesirable.

DarqueKnight

All good points Bruce.

I hesitated to suggest using the balance control to test the output of the SDA drivers because some preamps don't have them (as you alluded to) and some of the preamps that do have them will not fully attenuate the other channel when the balance control is turned all the way to one channel. My Adcom GFP-750 is one such preamp.

The dc resistance of my SDA 1.2TL's speakers remains the same whether the SDA cable is connected or not. Of course, dc resistance is not the same as ac impedance. I'll leave it to the interested reader to calculate the actual, frequency dependant impedance with and without the SDA cable.:p

quote:

---

My speakers also seem to be tougher without the SDA cable. I can turn them up louder on say rap music. Even though I'm not much of a fan of that type of music.

---

Hmmmm....well, I seldom "crank" my speakers and I seldom listen to rap "music". My sound lever meter measures an average 2 dB decrease in volume with the SDA cable of my 1.2TL's disconnected. Therefore, I had to turn up the volume a bit to get the same level without the SDA cable.

BlueMDPicker

Originally posted by DarqueKnight
While I can not reasonably expect Polk to reintroduce the SDA line, I would like to see them expand their replacement parts program to include improved drivers and crossovers.

And put those two guys in the back shop to work building enclosure kits!

Madisound (among many) make it financially through internet direct sales. And, most DIY customers seem quite pleased with the result of their labors. Polk discontinued its big box speakers long before the day of internet direct sales. I truly believe the larger SDA lines would be viable in kit form, if priced between $1500-2000. By eliminating the big slice of the pie (below), there's margin available for profits AND better components.

Tour2ma

Originally posted by DarqueKnight
All good points Bruce.

Thanks, but upon further review...

If there was some business lesson learned at the end of the SDA era, it did not stick. Otherwise how do you explain the development of the SRT? Maybe a bit of reinforcement was needed... and the SRT delivered that in spades.