• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

Polk SDA 2B Studio - good speakers?

S

Sandman175

New Member
Hi all,

I am new AK member & relatively new to vintage audio. I've been lurking around trying to learn for about the past year & am impressed & somewhat intimidated by the amount of experience & knowledge at AK. I purchased a pair of SDA 2B Studios & a Pioneer SX-780 last year off CL for my bedroom setup. I like them a lot but I'm a newbie. I read about a lot of classic speakers & hear some strong opinions on them, but not so much on the SDAs, specifically the that I have - these are the ones from 1987 with just 1 tweeter, 1 stereo driver & 1 SDA driver, & 1 bass radiator. I would appreciate any thoughts & opinions.
 
Register to hide this ad
Think they made two versions one with a pedestal base and one with a flat base. Did you get the connecting cable? Quite good speakers and well regarded. If you plan on opening them up, you may need a bit more power.
 
Thanks nclh77! I did get the connecting cable. And I was also thinking that I might need more power to get the best out of them. For now, I don't have enough room - or an understanding enough wife - to open them up. Good to hear that you think well of them. I think I did really well for my first vintage rig, receiver and speakers both in good condition, all for ~$150, from local CL seller. Since then I bought a Kenwood GE-1000 EQ to try & compensate for some of my br acoustic challenges (fairly small, plaster walls, tile floor, furniture, etc.). I realize that there are mixed opinions on EQs - but it looks cool, and that's worth something, lol! Anyway, thanks for reply, I've never posted before & thought I might have done something wrong, when I didn't get any replies for couple hours.
 
I believe that you have the C model. Supposed to be the latest best in that series from what I have read. There is a ton of info out there on the WWW.
I was a Polk fanboy till I got a set of Klipsch. Now nothing else will do for me that does not have a horn. I still have the Monitor5's and the SDA2a's still in my collection. Make sure you have the right amp to use with that extra cable that ties the two speakers together for that SDA sound. Some amps will blow up. I am useing a Crown XLS1500 to power my SDA's
 
Thanks! I did find a ton of info - so many versions! - & I'm pretty sure that I have the 2b Studios. I found gimpod.com & ve3mods.com to be helpful as I tried to confirm what I bought, lol! The SX-780 has the required common ground, but as nclh77 implied, I could use a more powerful amp to get the best out of them. Well, I'm sure the Klipsch speakers must be something to win you over. Maybe I'll get some as I get more into my new hobby. For now, I'm pretty happy with my first rig & glad both responses regarding the speakers have been pretty positive. Thanks again.
 
For the record, there is no SDA 2C. 2B was the last version. The 2B Studio is the same as the 2B, but instead of walnut caps on the top and bottom and cloth sides, it's just a wood grain vinyl. Most are black, some are brown.

ALL Polk SDAs are good speakers. They can do things that other speakers could only dream of. Balanced highs, killer bass, and of course the legendary wide soundstage. Although the 2B were toward the bottom of the line, they are still high end speakers and sound fantastic. You got an AWESOME deal on them if you paid $150 and got the SX-780 with them. The SX-780 usually goes for about $200-250 and the 2B Studios for about $200-300. I always say that Polk SDA speakers are the best deal in vintage audio. The resale price is ridiculously low for the amount of sound you get out of them. For instance, I owned a pair of Klipsch Chorus IIs at the same time as a pair of Polk SDA 2B Studios and determined that the SDA 2B was better in every way. And the Chorus II is a very well respected speaker. I sold them for $800. The 2B Studios cost me $180. So there ya go.

There are also a lot of useful upgrades you can do to them to make them sound even better. Polk still supports them. You can replace the tweeters with new units from Polk for $100 and that in itself will be a huge upgrade in sound quality.

The only problem with SDAs, and one of the reasons why they cost so little on the used market is because they have to be powered properly, and placed properly to sound good. I can tell you right now that you have FAR less power than they really need. Your 780 has 45 wpc, and any SDA owner with experience will tell you that you need at least 200 wpc. It's not about volume. The SDAs are actually fairly efficient speakers and will get loud enough on 20 watts of power. But their electronics are complicated and require a lot of current to get the woofers moving. I tried using my 2Bs with a 100 wpc receiver and they fell all over themselves. The bass was sloppy, the dynamics were poor. As soon as I hooked them up to my Crown XLS 1500 amp with 350 wpc, they came alive. HUGE difference. So I suggest the first thing you do is replace your amp. Get a separate amp/preamp combo. Maybe sell the 780 to pay for it. Regardless of what the guys in the Polk forum will say, you don't need to spend a lot on a high powered amp. Those guys HATE pro amps. Of course, the ones who say they hate them haven't heard a Crown XLS, so go figure. My Crown XLS 1500 cost me $175 brand new from Amazon and it drives my SDA SRS 2 (big ones) VERY well. They're discontinued now, but you can find them on ebay for not a whole lot more. If you like the Polks you need the power. Then you'll love them. It's worth the upgrade.

The other thing is spacing. You can cram SDAs into any old room and they'll sound good, but if you want the breathtaking soundstage, they need 3 feet of open space on either side of them and you need to sit at least as far away from them and they are from each other. So if you're 8' in front of them, place them about 10' apart and make sure you have 3' open on the outside of them. This usually means you need a long wall to place them on.

So if you don't have 200 watts or 3' on each side of them, you're not fully enjoying these awesome speakers.

Here's a good site for basic SDA info: http://www.polksda.com/
LOTS of good info in the SDA Handbook: http://vr3mods.com/uploads/SDA_Handbook_2011_Rev2.pdf

Hope this helps and I hope you can get the power and have the space to fully enjoy these awesome speakers. Once you find what they're truly capable of, you might find yourself upgrading to one of the big SRS models. That's what I did, and I haven't been able to find a better speaker.
 
Oh, and I meant to add that they don't need any EQ. They're actually one of the few speakers that I've found just right the way they are. Very well balanced across the board. But of course it's up to you if you use EQ or not.
 
Yeah, never was a 2C model. The OP mentions them as Studio model. The 2B Studio model has the black ash vinyl. While the 2A looks exactly the same, but with the walnut vinyl. The 2B with real wood top and bottom caps is usually more popular. And brings more money on the used market. And then there's the regular/original SDA2. Which usually brings the least money. And is also the least desirable model. Although I've never heard it. Many say that model does not image nearly as well as the later 2A/B models.

I'd recommend a minimum of 150 wpc power amp on them. More the better though. And should be a common ground amp if using the interconnect cable between the speakers.
 
Thanks all. Good to hear confirmation that I bought well for my 1st vintage rig - underpowered sx-780 notwithstanding. After reading the replies I did want to comment on a couple of things.
First, Rex81 got me thinking & I looked for the original CL ad to confirm what he was asking and can't find it. It was about 14 months ago & upon reflection, I think I may have paid more than $150 for receiver & speakers. I can't remember for sure but I think he may have been asking $150 for speakers & the receiver didn't enter the discussion until I saw it gathering dust in his garage. For sure, he included it for no more than $100 - and I do remember that he was a Pioneer guy & had an sx-1250 or 1280 playing inside. I think I may have talked him into $240 for all. So, maybe not the $150 I initially remembered but still pretty good.
Secondly, regarding the EQ, I tend to lean towards those who say they mostly diminish rather than improve sound quality. However, a lot of folks seem to think EQs can really help compensate for poor room acoustics. Since I'm sure that my smallish bedroom with it's plaster walls, tile floor & built-ins, is not an ideal space, I wanted to have the ability to make adjustments to offset some of the negative impact. And as I originally said - it looks cool & that is worth something, right?
Lastly, I have heard from enough knowledgeable folks that more power would definitely improve the speaker performance that I am convinced. However, I like the sound now so I plan to hold out until I can buy one of my dream amps/receivers. Right now, I'm lusting after one of the Sansui "Pure Power DC" receivers. I would love the g9000 & am actually considering a g8000 - of course the legendary g33000 is the ultimate dream! Although 200 wpc is suggested, I think the g8000 at 125 wpc, based on available current, headroom, etc. (look it up) should be plenty adequate for the SDA 2bs.
Anyway, thanks for the replies. I appreciate all of the perspectives and am sure I will continue to learn from you guys.
 
No doubt you can drive them with 120 wpc. Just don't get real happy with the volume knob and clip the speakers. You done well on that bundle. Normally the speakers alone go for a little more than what you paid for it all. Keep in mind the common ground amplifier they require if you are using the interconnect cable. Also....those vintage midwoofers are prone to magnet shift. Leaving the driver cone locked and inoperable. It is highly recommended to pull the midwoofers out. And use an adhesive like JBWeld to secure the magnet to the basket. To prevent shifting. Problem is the glue/adhesive used during manufacture of the driver tends to breakdown over the years. Thus the magnet can shift. Especially if the speaker cabinet takes a jolt. The magnet can be realigned if shift occurs though. So never throw a shifted driver away.

Congrats on getting them!
 
Thanks Halo71! I'm pretty sure that I will have to find a balance with this new hobby of mine. I bought a bunch of deoxit products, canned air & chip brushes earlier today so that I can clean away 38 yrs of built up dust in the receiver (it developed a slight issue that I posted on the Pioneer Audio forum). Doing more technical repairs/adjustments on the speakers &/or other components is a little daunting. I co-own a small business where I wear a lot of hats, so my available time is limited. I'd love to get more proficient with all aspects of vintage audio - finding, buying, collecting, repairing, enjoying, etc. - but I think that I'll be limited to finding, buying, & enjoying (with maybe a little cleaning and adjusting) for a while. I think I need to try & find a competent local technician to do the things my equipment will need until I gain more knowledge/skills & time. But thanks for the heads up on some potential issues that I need to check out!
 
IMG_0668.jpg

P1010030.jpg


Nothing wrong with Polks as I have owned several pairs. My old setup. SDA2A. Maybe someday I will replace the tweeter, as all other mods were done to them. Never got around to replace the tweeter.
 
Sandman, here's where I think you'll start having to make some tough decisions...

I used to be a vintage guy like you. Then I found Polk SDAs, and they made me reassess my priorities. They don't play well with vintage receivers, even the high powered ones. Head over to the Polk forum and nobody is running a receiver. They've all found that you need a dedicated amp. 125 wpc is considered a monster of a vintage receiver, and a lot of guys really like them. Nostalgia, all those buttons and knobs, tons of silver, old school build quality, etc. I get it. As you can see by my avatar, I like vintage receivers too. But I STRONGLY suggest getting a newer, more capable amp to drive those SDAs. Again, it's not about volume. They'll get plenty loud. It's about current, headroom, and sound quality. There's a lot going on inside that speaker that really takes a toll on receivers. They just weren't designed to handle what the SDAs require. I liked the sound of the SDAs so much that I was willing to look in a different direction.

If you really like the vintage receivers, use one as a preamp. It needs to have preamp outputs (or pre outs), which I don't think your 780 does. Plug an amp into some pre out jacks on a vintage receiver and that allows you to have everything you like about the receiver, but completely bypasses the amp section to use the better, more powerful amp to power the speakers. This can also be a much cheaper option. An unrestored G8000 at 120 wpc is going to set you back about $900 and there's no guarantee it won't need a good deal of work sometime soon. For $200 you can get a nearly new Crown XLS amp still under warranty that runs 350 wpc into 8 ohms and is stable down to 2 ohms. Something that even the best vintage receiver can't claim. Then you'll have an amp that is comfortable powering any speaker you ever buy in the future, including the bigger SDAs in the line. And you won't have to worry about all the reliability issues with the vintage gear, which it sounds like you're already starting to see.

You're going to get lots of advice from a lot of different people and it's all coming from a good place. We all have different experiences. And of course time and budget will be limiting factors. Just wanted to add my two cents.
 
Thanks for the advice. I know modern amps are a potentially cheaper option & I may need to go that route at some point.

There are basically three reasons that I don't want to buy a more powerful modern amp to power my SDAs at this time. First, I have researched the mid-late 70s receivers & amps quite a bite & feel that I understand their capabilities pretty well. Second, I dig the look. And third, I don't understand modern amp performance ratings at all.

It gets confusing when trying to compare power ratings of vintage vs modern amps. I am not knowledgeable enough to state any of the following as indisputable facts but I do have some worries regarding the more modern gear. I've read many threads and articles claiming that the ratings of vintage gear - especially for several years beginning in 1974 & as the govt tried to protect consumers from potential fraudulent claims during the receiver wars of that era - is much more conservative than ratings of modern amps. My understanding (limited) is that amps rated during that period had to produce continuous power to both channels for 1+ hours over the full 20hz to 20khz spectrum without building up heat, etc. & still providing lower THD than many modern amps. The g8000 for example has a THD of .03. Also, that today's ratings are less strict and less regulated such that there are examples where 100 watt rated amps are measured at 1 kHz only and for only 1 channel. I did look at the Crown XLS advertised ratings & saw that they are for 4 ohm speakers, significantly less for 8 ohm speakers, & that the XLS series are recommended for portable PA. I'm not even sure what that means.

Rex81, Based on your experience, I'm sure the Crown XLS series are good amps with plenty of power & they would drive my SDAs very well; and for sure I could save time & money. I'll probably end up taking your advice at some point. But for now & until I understand performance, testing, & ratings better, I'll probably try & go with the mid-late 70s gear that I feel more comfortable with, assuming that I can find & buy it.

Of course, a year or two from now, I'll probably post that I couldn't get the best out of the SDAs until I gave in & took your advice, lol! Thanks again!
 
No problem. It sounds like you're well on your way to building some solid knowledge of your own. It's a fun journey. One thing that makes it so fun is all the different opinions out there! Just make sure you're adding extra weight to the opinions of those who hear things for themselves. There are plenty of people that will share opinions on gear they've never heard. :dunno:

All the stuff you mentioned about specs on vintage amps is true. They're rated at "real" watts, which are more rigorously tested than the rating you'll see on a new RCA sound system at Walmart. But don't think of it as "old watts" vs "new watts". Think of it as "real watts" and "not real watts". Any serious audio gear, new or old, will be rated in real watts. Yes, that Crown generates 350 real watts of power into each channel at 8 ohms, 525 watts into 4, and over 1,000 real watts into a single channel when bridged mono. So yes, it really is 3 times as powerful as a G8000. No, the THD on the Crown is not spec’d as good as some of the vintage units. But here’s another lesson: THD doesn’t mean as much as people say it does. I guarantee you can’t hear 1% distortion, let alone the difference between .1% and .03%. And THD is measured differently by each manufacturer anyway.


An important spec to look at is what ohms it’s rated at. Most vintage units are only rated at 8 ohm operation and struggle with 4 ohm loads. That’s why there are warning signs on the back of them saying to only connect 2 sets of speakers if they’re 8 ohm only. Anything less than that and it strains the amp. Beefy modern amps have no problem with 4 ohm loads and some, like the Crown don’t mind 2. Some really nice speakers will easily dip into the 4 ohm and 2 ohm range, and can blow up lesser amps.


And finally, the other thing is to not let marketing get in the way of a good buy. The Crown is a “pro” amp. Some people will tell you that professional automatically means it can’t be used in the home. I think that’s ridiculous. They’ll tell you it’s not musical. That just means it’s not colored. It puts out exactly what was put into it. The only real reason I can find for someone not wanting a pro amp in their home system is because they tend to be butt ugly. So if looks is a real issue for someone, I can see why they wouldn’t want one. Power output, reliability, affordability, efficiency, and sound quality are what I’m looking for in an amp.


I know it sounds like I’m pushing the Crown hard. I’m not a Crown employee, so I have no interest in getting people to buy them, only that I personally think it’s a good purchase for someone needing a lot of watts on a budget. My point here is that new amps can stomp all over old amps in a lot of ways including sheer power, reliability, efficiency and affordability. So don’t automatically assume an old receiver is better. Usually the only thing better is looks and collectability.
 
The other thing is that depending on your room and tastes, it's possible that the SDAs aren't for you. If you really like the vintage receivers and don't have 3' of open space outside of the speakers, you may be happier with something like the Klipsch Forte II. Similar size as the SDA 2B Studio, better looking in my opinion (certainly a more vintage look), and they'll run fine on any little receiver you can find because they're so efficient. They'll run you a little more than the Polks (about $600-800), but you wouldn't need to upgrade your power for them, saving you some money there. I don't think they sound quite as good and won't deliver the epic sound stage, but they're close, and plenty will say they're better.
 
Rex81, thanks again. I have read about several of your points, especially that the really low THD ratings are much less significant than what we might expect, given the most important fact that we can't hear the difference. We didn't get into slew rates and some of the other measurements that can affect performance & the vague concept of musicality, but all of your points are valid & I may eventually become convinced. But for now, I'll stick to vintage, assuming that I can find & buy what I want. Regarding the "fit" of the SDAs, I know my space is less than ideal & I do want a more powerful amp/receiver but I really like the speakers even now. I expect to have a better place to set them up within the next couple years & to have a more powerful amp/receiver to get the best out of them. In the meantime, I'll probably continue to scout for vintage bargains & likely keep the sx-780 for my bedroom setup with different (bargain) speakers. Hopefully, I'll get at least the Sansui g8000 & possibly even the g9000, g22000, or the ultimate g33000 to eventually pair with the SDAs. Regardless, I first realized almost 40 years ago - when I couldn't afford true hi-fi but enjoyed listening to the systems of others who could - that there is no perfect system, or even perfect component. Good? - yes, Great? -yes, almost perfect for an application? - certainly. But tastes change, needs change, approaches change, and I expect to enjoy the process of finding, buying, putting together, tweaking, and enjoying different setups, hopefully for the rest of my life. Thanks again.
 
I have a pair of SDA SRS 2, which Rex81 has and I agree on power and placement. fI you lack in either one, I would suggest a different speaker. I use a Yamaha PC2002M, which are available in good shape for around $500 -700 and it made a huge difference over a 150 watt receiver that I had. It's truly a unique sound, which is not for everybody, but I enjoy it immensely.
 
You must log in or register to reply here.
Back
Top Bottom