Anecdotal Insights From An SDA Cultist

DarqueKnight

Part I-History and Specifics

DarqueKnight wrote: »

After a couple decades of dealing with these wonderful speakers, I've come to the following conclusion:

SDA's are some of the most power hungry, current guzzling, acoustically demanding and land grabbing speakers ever made.

I'll expound on the statement above in another thread...after my thoughts soak a while longer.

Now that my thoughts are through soaking, I’m ready to expound. But first, some personal history.

Being Lured In

I remember it like it happened yesterday, although it was nearly 23 years ago on a crisp Saturday afternoon in November of 1985. The ink was barely dry on my B.S. in electrical engineering diploma and I had already come under the influence of some fellow engineers, at work, who were avid audio enthusiasts. They were quite helpful in providing advice as I was working to put together a “nice” stereo system. I had gotten the idea that the Kenwood receiver, Sony turntable, Sony cassette deck and Advent speakers, from my college days, weren’t cutting it anymore. It was suggested that I visit Audio Electronics in Overland Park, Kansas and I did. I was greeted by the proprietor and I explained that I was looking for new speakers. The nice man asked what kind of music I listened to and I replied “mostly jazz”. He said “I’ve got just what you need” and lead me to one of his establishment’s listening rooms, where a large pair of black monolithic speakers was set up. I immediately said “Oh no, I don’t want anything that big”. “Calm down. I just wanted you to hear these. This is Polk Audio’s best, the SDA SRS. I haven’t heard a better speaker for reproducing jazz. There are much smaller speakers in the line”. I agreed to listen to one song, just to be polite. He played Herbie Hancock’s “Chameleon” from the “Headhunters” LP. One song turned into a couple of hours. Regrettably, because of room size and budget constraints, I couldn’t even take home the “baby” SDA, the CRS. The dealer was quite forthright in explaining the need for adequate room space and quality amplification. He recommended the Monitor 10’s and that is what I purchased 4 months later. I left the store and started reading everything I could find on Polk Audio and SDA. Of course, I auditioned other speaker brands, but as I shopped around more, I came to realize that Polk’s price to performance ratio was going to be hard to beat.

I did not purchase a pair of SDA’s, the 1B’s, until February of 1987. The rest, of course, is history.


SDA Power Hunger

SDA’s are a true cult product because, if you don’t have special, hidden, secret, inside knowledge, you’ll mess up. A 1985 Polk brochure states:

“Power handling is nominally rated at 1000 watts per channel for the SRS and 750 watts for the SRS2, although the high efficiency of the systems allows superb performance to be realized with a good quality receiver.”

and

“Recommended associated amplification for the SDA SRS is 10 to 1000 watts per channel.”

A brochure for the SDA SRS 1.2TL recommended amplification in the range of 50 to 1000 watts. That same brochure stated:

“The SRS 2.3TL and 1.2TL, each with a bass radiating area exceeding that of a 40” woofer, have the ability to produce powerful, deep bass with virtually no distortion.”

Let’s see: whether we are dealing with the SRS or the SRS 1.2TL, we are talking about running a sealed cabinet speaker with eight active drivers and four tweeters with 10 or 50 watts, right? A virtual 40 inch woofer will sound great with 10 or 50 watts won’t it? Sure Mac…sure…in your dream of dreams. Of course you can hook up your SRS’s to a funky little 20 watt receiver and get some sound, but don’t expect it to be optimal or anywhere near representative of the speaker’s true capabilities. In my experience, my SDA’s, from the CRS+ to the 1.2TL, have laughed, giggled, grinned or dozed off to sleep at anything less than 200 watts per channel. I tried to run the CRS+’s in my office rig at work with 1) a 90 watt Sony integrated amp and 2) an Adcom 125 watt power amp. I was not happy. The bass and overall clarity suffered. An Adcom GFA-555 Mk II (200 wpc) fit the bill. Sure, SDA’s can be driven by low power amps, but they can’t be properly “handled” by such amps.

With my 1.2TL’s, as I went up in amplification power and quality, the SDA sound stage became wider, deeper, and more three-dimensional. Images within the sound stage became heavier, more “solid” and more firmly fixed in space. Reviewers for the now defunct “Stereo Review” magazine used to state that SDA’s were not capable of the “pinpoint” imaging demonstrated by some other speakers. I’m sure that was true with the amplification they were using. However, with high quality, low noise, high power, high current amplification, I have found all my SDA’s to be quite capable of “locking” an image in three-dimensional space. With the right quality and quantity of “juice”, they are capable of conveying the apparent size and weight of that image.

Yes, you can run SDA’s with a low powered receiver, but why try to get away with using cheap, compromised electronics? SDA’s were (and many still consider them to be) Polk’s flagship speaker series. It stands to reason that they would require flagship electronics to realize their optimum performance.


SDA Current Guzzling

I have heard a few times and read many times that “the CRS is the best imaging SDA”. No it isn’t. The CRS is the smallest SDA speaker and the least demanding load on an amplifier. Therefore, it may sound “better” in a particular room with a particular set of electronics. Take the grilles off and take a good look at the front of a CRS+ and a 1.2TL. The 1.2TL has 4X the amount of tweeters and drivers. In fact, the driver/tweeter section of the 1.2TL baffle board looks like 4 CRS+ driver arrangements vertically stacked. The 1.2TL has 4X the SDA effect and moves over 4X the amount of air. The CRS+ is a mere child compared to the 1.2TL.

I can demonstrate empirically and unequivocally that none of the three CRS+ pairs I own sound anywhere near as good as the 1.2TL’s in my living room. If they did, that is what I would be running in my two channel system.;) Now, If we move to my home office or master bedroom, the CRS+’s would outshine the 1.2TL’s because the 1.2TL’s performance would be compromised by the lesser electronics and smaller room size.

Let’s review some more cultish, secret, hidden, inside knowledge. I have several original SDA brochures. I could not find mention of the requirement for high current amplification in any of them. I also did not find mention of the requirement for common ground amplification, although the manuals do mention this and the dealers I dealt with specifically pointed this out.

I did not find the high current amplifier requirement explicitly mentioned in my SRS, SRS 1.2TL, or CRS+ manuals. The manuals do state that:

“…amplifiers that are comfortable driving low impedances and do not have excessive current limiting will be better suited to the SDA, especially at higher listening levels.” [Emphasis mine.]

Let’s consider a pair of SDA SRS 1.2TL’s. What does the amplifier see per channel? First, a maze of crossover components with that big honking inductor coil. You know the one I’m talking about. After all that, the current signal from the crossover is split twelve ways among eight drivers and four tweeters. Good luck to the poor current signal. I hope the amp fed it properly before it went out into the world.


SDA Acoustic Demands And Land Grabbing

SDA’s range in width from approximately 16 to 20 inches. The manuals specify a minimum inner spacing of 4 feet, with 6 to 8 feet being optimal. The minimum spacing to the side walls is 3 feet. This means that, for the 4 foot inner spacing, the 16” wide SDA’s require a minimum rear wall length of 12 feet 8 inches. The 20” wide SDA’s require a minimum rear wall length of 13 feet 4 inches. The manuals specify sitting at a point in front of and between the speakers that is no closer than the distance between them. The manuals further state that a minimum distance of 10 feet front and center from the speakers is optimal.

If we use a room with suboptimal minimum spacing, we could “get away with” room dimensions of 12 feet 8 inches by 5 feet for the 16 inch wide SDA’s and room dimensions of 13 feet 4 inches by 5 feet for the 20 inch wide SDA’s. Please be advised that the listener’s head will only be 1 foot from the wall behind the listening position.

If we want to be reasonable, and nice, and use a room with optimal minimum spacing, we would need room dimensions of 14 feet 8 inches by 12 feet for the 16 inch wide SDA’s and 15 feet 4 inches by 12 feet for the 20 inch wide SDA’s. This allows for 2 feet of space behind the listening position.

Therefore, for best sound with SDA’s, a room approximately 15 feet wide by 12 feet is the minimum requirement. I am just getting by with my 1.2TL’s in a room 20 feet wide by 17 feet.

DarqueKnight

I have found that the SDA sound stage grows with better quality amplification. When I had an Adcom GFA-5802 amp, the sound stage boundary was typically 3 feet on each side beyond both speakers. When I switched to the Parasound JC 1 mono amps, the sound stage width extended another 4 feet on each side.

When I first auditioned SDA’s, there was a nice man to tell me that, even if I had the budget, I just didn’t have the real estate required, even for the smallest SDA. I wonder how many people put SDA’s in a 10 foot by 10 foot room with a 30 watt receiver and then **** about the “muddy” sound.

I looked through the old sales brochures and magazine ads again and found no mention of the real estate requirements for SDA’s. I guess that was part of the inside knowledge package that the dealers were supposed to pass along to unsuspecting potential buyers. When I eventually bought my first pair of SDA’s, the salesman did ask about my room size and configuration. My heart goes out to the unsuspecting folks who acquire SDA’s on the used market and who have no access to concerned care and counsel about the proper setup and operation of these wonderful examples of audio art and science. Some of these poor souls buy SDA’s without the interconnect cable and never stumble upon the truth. Some of them only find out about the interconnect cable when they attempt to resell the speakers. Cable? What cable?


SDA Shopping

This is such a world of hurt. It’s so sad that you just can’t ask the normal questions usually posed to a seller of used audio gear such as those regarding age, cosmetic condition, functional condition, and repair history. Nope. The first thing you have to do is figure out what is actually being offered for sale. The seller often does not know what he or she has. With all the model versions, transitional models, inappropriate parts swapping, bootleg “upgrades”, cosmetic cabinet modifications, and incomplete model labeling on the back, a bit of detective work is often required to determine the actual SDA model up for sale. This detective work usually requires taking a peek inside to look at crossover and driver labels. Good luck.


Further Thoughts - 21st Century SDA’s

If Polk ever does resurrect the SDA series, I hope they inform the potential buyer, in the sales literature, of the power, current and room size requirements. A lot of misunderstandings, disappointments and ill will can be avoided this way. On the other hand, a large part of the fun of being in a secretive cult is keeping outsiders in the dark about the inner workings of the cult.

In case there are some society members in a state of alarm over my revealing cult secrets, just remember that the only people reading this are the ones who already know all the secrets anyway and that most people in this country hate to read. The very best way to hide something in plain sight is to put it in some type of written document, preferably a nice, thick book. Written secrets can be further secured if there are no pictures or brightly colored graphics to attract the attention of a reader. For example: We still have people stopping by to ask for SDA schematics.


Part 2-Random Questions And Answers

It’s rather irksome the way you guys rave about these speakers as if they are the be all and end all to audio speaker design.

Why is it irksome? We are not forcing anyone to accept SDA’s in their rig. You either like them or you don’t. If someone does not like what I like, I do not like what I like any less. If we are delusional, then what is that to get mad about? You like what you like and we like what we like. We all like different things. Peace be upon us.

I think most SDA cultists are aware that SDA’s, like anything else conceived by the mind of man, are imperfect. We do, as a group, exhibit a lot of enthusiasm for the series, maybe even more so than enthusiasts for other vintage speakers. However, this is merely indicative of the enjoyment we derive from the speakers and is in no way meant to be derisive of other speaker brands and designs. Personally, I have not found anything I like better in over 20 years of listening. I found my sound a long time ago and stuck to it. I began a major upgrade project for my two channel system in 2006, which is still going on. One of my friends keeps asking me when am I going to get new speakers. I reply that I get “new” speakers each time I upgrade my amps, source components, and cables. I also got “new” speakers when I upgraded the tweeters, grille cloth, SDA cable and crossover components. Such good sound.

It’s not our fault if other people don’t like their speakers as much as we like ours. The term “sour grapes” comes to mind.:)

You know, there are better speakers out there.

Better in what regard? Looks? Sound staging? Detail? Imaging? Quality of materials? Quality of construction? Higher cost? Snob appeal? Better depends on what your priorities are. One of my top audio priorities is life-like, life-size three-dimensional sound staging. I haven’t found a speaker with better or even equivalent spatial properties to the SDA’s, and I have been looking for over 20 years. I visited Dunlavy Audio Labs a few years ago. While I was there, I listened to their $35,000 flagship speaker. The sheer size, dynamics and power of the sound stage was quite impressive. However, I found that the sound stage “collapsed” if I did not maintain my head, as if it were in a vice, in one point exactly between the speakers. The modified SDA 1C’s I was using at the time, had a sweet spot approximately 3 feet wide. I didn’t like my 1C’s any less after listening to the $35,000 Dunlavy flagships.

If SDA’s were so great and wonderful, why’d they stop making them? Gotcha!

No, you didn’t “get” me. SDA’s were Polk’s flagship series from 1982 to 1991. Nine years is a very, very long time for a consumer electronics series of products. Even though the SDA series was discontinued 17 years ago, replacement parts, even higher quality replacement parts, and customer support is still available for the series. This is remarkable for a speaker series introduced 26 years ago. How many Infinity owners can make the same claim?

I’m glad you brought up replacement parts. What about that garbage SL2000 tweeter? No comment?

Yes, I have some comments. Every speaker design has it’s “Achilles heel”. The SL1000 and SL2000 tweeters were the Achilles heels of the SDA series. This was acknowledged by Polk. The 13 kHz resonance mostly affected upper harmonics. Most speakers, even some highly regarded and very expensive ones, have some type of frequency response aberration. Lots of manufacturers just don't disclose theirs. Polk’s first solution was the SL3000 tweeter. In 2003, 12 years after the SDA series was discontinued, Polk developed a new silk dome tweeter that addressed the resonance problems of the SL1000 and SL2000 tweeters. Although the SL3000 did not suffer from the resonance issue, Polk developed a silk dome replacement with more detail and lower grain. Some people still prefer the sound of the SL2000 and SL3000 tweeters. It’s a matter of taste.

The “Achilles heel” of a lot of the vintage Infinity speakers was poor build quality. Good sound…when they weren’t in the repair shop. Read some of the reviews from the 1980’s.

The “Achilles heel” of the highly acclaimed and very expensive Dunlavy speakers was their miniscule “sweet spot”. What is Dunlavy Audio Labs doing to address that issue for their embedded customer base?

You know DAL went out of business in November of 2002.

Oh…yeah. I forgot.

Don’t you people ever get tired of listening to the same speakers?

Well, I can’t speak for my fellow society members, but I personally don’t listen to speakers. I listen to music. Speakers and electronics are just means to facilitate the enjoyment of music. I don’t pursue audio gear for gear’s sake. I pursue gear for music’s sake.

You know, I have a friend, a fellow saxophonist, who finds it a little bit irritating that I have been playing the same saxophones, mouthpieces, and brand of reeds for the last 15 years. He, on the other hand, has a new instrument, mouthpiece, or brand of reeds every time I see him. He says he is always looking for something to give his playing and sound that extra “edge”. I find that I sound pretty much the same no matter the equipment I am using. The only thing I have found to give my playing and sound that extra “edge” is practice, practice, and more practice. I suspect my friend is a little bit envious of the affection, trust, and confidence I have established with my current instruments and accessories. Not having to constantly get acquainted with a new instrument every day frees me to concentrate on making music. I really don’t mind if my friend switches instruments for every successive page of sheet music. He makes his music his way and I make my music my way. There is no right or wrong to either approach.

To each his own.

engtaz

Thanks you. That was a nice write up.

engtaz

dorokusai

Nice write-up Raife. I'm not sure if you view it the same way, since you didn't mention it, but SDA is still in use today. It might be in a different form per se but it still lives on. I think that's certainly a testament to the staying power of the technology and naturally, the whole idea in the first place.

dcmeigs

The seller often does not know what he or she has.

Ain't that the truth. My craigslist SDA-2As turned out to be 2Bs when I pulled the PR for a look under the hood. The owner never knew what that "strange little socket" was for either. He was aware that each speaker had a bad driver. Hooboy.

Nice post.

analog97

Dark One:

Thanks for this tremendously helpful and informative post. I, too have the 1.2TL's and have many similar experiences and similarities in judgment as you, especially with regard to the proper amplification for the 1.2TL's. Each and every time I've thrown more current at them, they improve. I have never heard them with something as beefy as your JC1's and would love to. In fact, I am in the market for something like that now. I also have a 26x20 room, which is quite an important consideration as you know. I also recall something being said by Polk in a "white page" about the speaker demands of the 1.2TL presenting a more difficult load, as opposed to the simply stated requirements for amplification.

Thanks for your time and thoughtful post!:)

Mike Reeter

Thanks for the great write-up Raife...The realestate needed to let the SDA's breath is indeed huge,I would love to have a dedicated room of around 20x16

SDA SRS 1.2

Excellent post Raife! Printing those excellent thoughts out and adding them to the Compendium. Thanks!

Robbie

F1nut

Raife, thanks for sharing your thoughts.

In my 19 years of SDA ownership, I too have yet to hear another speaker that could replace them.

Long live SDA.

george daniel

You know,, that was just a good,factual, and sensible read. No hype,,no manufacturers' claims, a well thought out common sense "snapshot" regarding the SDA series. Thanks for sharing that,,an exceptional read,,sir,,,thank you.

Ron Temple

Very entertaining Sunday read...thanks.

Ivorytooth

Great posts!! I too have been a SDA cultist for 20 years.


I am not sure I have the power, but I have the real estate for them. They have never sounded better!

zingo

Thanks for sharing your thoughts with us Raife; I always appreciate it as I'm sure others do also. SDAs are an interesting beast with many different facets, and it's nice to hear a "seasoned" perspective.

ajcutler53

Very interesting insights and observations. Raife, I enjoyed reading them. What really resonated with me was your view on not listening to the speakers, but the sound they produce, and how the SDAs get renewed with every change you make in them and the components they get connected to.

BSUfbfan

Very good points Raife! I had an audiophile friend listen to my 2.3's recently and one of his comments struck me... he closed his eyes and said he was amazed at how such a large speaker dissapears once the music starts... amen!

rayslifecycle

Thanks for your excellent write up.
I am new to polk speakers as I have been finding them at the local flee market - luckily every speaker I have bought has worked flawlessly. I just recently upgraded my integrated amp to a denon 3808 with 160 watts/per channel and the speakers openned up.

Question:
In using SDA-CRS for the rear channel of my AV system - would they benefit from the crossover cable?

heiney9

Excellent post Raife!

Fatbrando

Bump...!

Big Up to DarqueKnight!!!

Got my Greedlust a burnin' for dem Polkies....!!!!

FB

ben62670

DK rocks!

HB27

DK, Excellent job.
"My heart goes out to the unsuspecting folks who acquire SDA’s on the used market and who have no access to concerned care and counsel about the proper setup and operation of these wonderful examples of audio art and science."
Excellent write up. I'm just learning SDAs. I made a huge mistake trying to put a huge SDA SRS 2 in a small room. I was TOTALLY unhappy. Going to the smaller 2A has opened up the SDA world to me. I consider myself pretty knowledgeable in audio and I'm learning every day the nuances of this new to me speaker. I'm very impressed with the sound of this speaker. It's put the fun back into tinkering with the accessories and amplification required to get the most balanced sound I can from these. The music is excellent and I look forward daily to another session of learning these fantastic speakers.
Thank you for bringing this out.
Harry

MillerLiteScott

Raife, Awesome write up again.

Both pairs of SDA's I have purchased were the PO getting those big ugly 80's looking speakers out of their house. Like BSUfbfan mentioned in his post above, my SDA 2B's now disappear playing music in my house. Actually they really do disappear, mine sound as if my whole front wall is a speaker with an enveloping sound on both sides yet you can still pin point all sources of the music. Mine even separate and place vocalist standing next to each other singing into their own microphones.

I have found the 2B to be the proper size for my room. I think if I went to a larger model my listening experience would suffer.

Such Good Sound. When Polk produces the next SDA 2 channel speaker series, they should be called the SDA SGS Series.:D

Thanks again for your post.

Scott

nadams

That's a lot of reading. Could you put it together in some sort of comic strip?

DarqueKnight

I'm not much of a cartoonist. Some of the fellows over at Audioholics would probably be eager to translate the text into comics form.

Driver_King

I have the Onkyo TX-SR805 powering my SDA II's. I've thought of going separates but am waiting for the right time. I don't know what kind of power I'm getting to my SDA's. The amp spec sheet isn't very helpful as it doesn't show how much power is delivered at 4ohms. At 6 ohms, it says my amp is capable of 160 watts. Could anyone help me there? By the way, nice article.:cool:

nikolas812

Driver_King wrote: »

I have the Onkyo TX-SR805 powering my SDA II's. I've thought of going separates but am waiting for the right time. I don't know what kind of power I'm getting to my SDA's. The amp spec sheet isn't very helpful as it doesn't show how much power is delivered at 4ohms. At 6 ohms, it says my amp is capable of 160 watts. Could anyone help me there? By the way, nice article.:cool:

You should start a separate thread in the electronics section....




Nice write up!!!

I really enjoyed it..




Nick

nadams

DarqueKnight wrote: »

I'm not much of a cartoonist. Some of the fellows over at Audioholics would probably be eager to translate the text into comics form.

I hope you realise that I was joking in reference to your divulging the SDA secrets to those only willing to read . I read through the whole thing in depth and enjoyed it quite a lot. Though now I feel sad that I'm only upgrading my amp from 60 watts to 100.

DarqueKnight

I was joking along with you. Sometimes my sarcasm isn't effectively conveyed.:)

ben62670

I wish I could write like you.
This is my favorite part:)

You know, there are better speakers out there.

Better in what regard? Looks? Sound staging? Detail? Imaging? Quality of materials? Quality of construction? Higher cost? Snob appeal? Better depends on what your priorities are. One of my top audio priorities is life-like, life-size three-dimensional sound staging. I haven’t found a speaker with better or even equivalent spatial properties to the SDA’s, and I have been looking for over 20 years. I visited Dunlavy Audio Labs a few years ago. While I was there, I listened to their $35,000 flagship speaker. The sheer size, dynamics and power of the sound stage was quite impressive. However, I found that the sound stage “collapsed” if I did not maintain my head, as if it were in a vice, in one point exactly between the speakers. The modified SDA 1C’s I was using at the time, had a sweet spot approximately 3 feet wide. I didn’t like my 1C’s any less after listening to the $35,000 Dunlavy flagships.

Everytime I go out and listen to real fancy expensive speakers I come home, and fire up my system. All those wants and desires just fade away. I can honestly say even if I had it going on like Bill Gates I would still own a pair or 20 SDA's:D

brody05

I have never had the experiance of listening to the SDA's but guess the imaging and sound stage must be the same theory as the SRT's?

If this is the case then yes, nothing can ever measure up to that, I had some, sold them after 5 years, couldn't live without them and got some more.

Great write up.