New to me 3.1tl... Upgrade

gtianz

I just got a beautiful pair of polk srs 3.1tl's. These things are in almost perfect condition.

I'm satisfied and impressed by the sound quality and these things definitely rock. Im driving them with an Emotiva XPA-2 that i picked up when my vintage onkyo tx-8500 mk ii (beast solid state 160 w/ch) didnt seem up to the task.

I have done the rd0198 tweeter upgrade. The tweeter upgrade definitely softened up the top end.

I also own a pair of Dahlquist DQ-10's. Comparing the two is very interesting.

The dahlquist are very laid back, smooth, and sound perfectly balanced (almost like listening to a single driver per speaker). + They almost image as well as the polk's.

Polk 3.1's:
Capable of achieving much higher volume levels.
Higher level of clarity and accuracy.
Vastly superior bottom end.
Not as smooth or well balanced as the DQ-10's.

With all that said i will finally get to the point of the post.

Should I start along the crossover upgrade path for the polk's? Will i achieve a significant improvement in sound quality doing the upgrades? Should I hold off investing a lot of money into these speakers and seek out 1.2's or 2.3's?

ken brydson

I have no advise but welcome to CP. They look awesome. Hope you find the sound you are looking for.

Mike Reeter

Your room size would have a lot to do with your decision, the larger SDA's need plenty of breathing room to sound their best.

The 3.1's are a very good speaker and can be an easier fit in a smaller space, but will perform to the task in any size room, very versatile.

Being that your 3.1's are in wonderful physical condition, I wouldn't hesitate to upgrade them as far as I wanted to.

The RDO tweeters are a good start, the x-over upgrade ( and other tweaks ) will make them "whole" again and will sound better than when they were new.

westmassguy

Welcome to CP. Very nice pair. As Mike pointed out, room size had a lot to do with which model is appropriate. The New Tweeters are an improvement, but are being held back by the aging and poor quality components in the crossover. The same holds true for the woofers. The Electrolytic Caps used in the Lo-Pass section, were garbage when new, and only get worse over time. The Bass can be improved somewhat, with upgraded Sub-Bass Drive Inductors. Your model only has a single Dimensional Woofer, so the bass improvement will not be as pronounced as those models that have equal numbers of Stereo and Dimensional woofers. The remaining upgrades to the cabinets, can be done incrementally, and their effect is cumulative.
Welcome to the Rabbit Hole, enjoy the ride.

TNTsTunes

In for the build.

I will be building my own to boot.

gtianz

Thank you Mike and West Mass guy.

I like these speakers. Think I'll jump in the rabbit hole. I will have to start pricing out all the components needed to see how much this is going to cost me.

I've done some forum searches but I haven't seen much info/documentation from anyone who's done 3.1 upgrades. I have perused VR3's website as well. Does anyone have any build threads, links, or documentation they could point me towards. I have the 70+ page SDA pdf file.

It's been 25+ years since I've done any soldering/wiring and I can freely admit that I'm not all that savvy making sense of wiring diagrams and the such. I have a feeling that I may require a little hand-holding to get through this process.

I guess to start I will ask if anyone knows if I have to have a new circuit board printed to account for the larger cross-over components? I have seen that many of the other models require new circuit boards.

This should be fun. I'll document the whole process (assuming it isn't cost prohibitive).

Ian

westmassguy

The new boards are made by CP Member Gimpod, and VR3/Trey sells them They're not required, they just make mounting the larger caps easier. I've rebuilt probably 50+ SDA and SRS crossovers, and have never had a problem mounting the new caps.

TNTsTunes

I just got my new to me 3.1 TL's up and going safely. They have full Sonic caps. Mills resistors dynamat deadened drivers, upgraded binding posts and need to have the cabinets reworked and dampened.

Spent a few hours listening tonight. Moving my AI-1 Dreadnouht into the system really helped. I'll need to build another one for it... I'm going to swap the 18mh inducer with a 16.8mh inducer I have to add some bass response soon.

Fixing the cabinets is where the main gain will be at for me. I have Toolmans speaker rings coming, some more dynamat for the drivers, some Sonic Barrier to add when I redo the end caps and seal all the cabinet leaks this winter.


I would think crossover work will be a great benefit for you at this point.

Mr. Bubbles

Comparing these two speakers is sort of like comparing apples and oranges. They are two totally different animals. One thing that stood out to me was that you said the DQ's image almost as good as the Polks. I would not think that to be the case at all. This makes me wonder if something is wrong with the Polk set up.

Upgrades/ mods will make a tremendous improvement in the Polks and the 3.1 seems to be one of the favorites in the lineup. Congrats on the speakeres, good luck with and enjoy any mods you decide on, and welcome to the Forums.

markamerica

Welcome, and congrats on the 3.1TLs!

gtianz

TNTsTunes wrote: »

I just got my new to me 3.1 TL's up and going safely. They have full Sonic caps. Mills resistors dynamat deadened drivers, upgraded binding posts and need to have the cabinets reworked and dampened.

Spent a few hours listening tonight. Moving my AI-1 Dreadnouht into the system really helped. I'll need to build another one for it... I'm going to swap the 18mh inducer with a 16.8mh inducer I have to add some bass response soon.

Fixing the cabinets is where the main gain will be at for me. I have Toolmans speaker rings coming, some more dynamat for the drivers, some Sonic Barrier to add when I redo the end caps and seal all the cabinet leaks this winter.


I would think crossover work will be a great benefit for you at this point.

Very nice and thank you for posting. Do you happen to have a build thread?

TNTsTunes

gtianz wrote: »

Very nice and thank you for posting. Do you happen to have a build thread?

Gotta look for it. Been busy listening to my 2.3's this morning.

gtianz

Mr bubbles.

I have the polks flat to the wall. 6 ft apart. The room isn't ideal. It is open on one side - I am using a sub RCA cable with the tabs broken off as the speakers didnt come with an interconnect. I have tested and the interconnect cable/speakers are working.

here is the room:

Schurkey

gtianz wrote: »

I am using a sub RCA cable with the tabs broken off as the speakers didnt come with an interconnect. I have tested and the interconnect cable/speakers are working.

There's at least some of the problem. An RCA cable is likely to have considerable resistance due to the tiny conductor. Step up to a 16-gauge or larger conductor. The SDA speakers should out-image nearly any other speaker.

dromunds

Dahlquists image extremely well.

GlennDog

dromunds wrote: »

Dahlquists image extremely well.

Absolutely !

gtianz

I will eventually do something about the interconnect cable. I was eyeing the VR3 terminal plates. Looks like a nice piece of kit.

Thank you Dromunds and Glenndog. I didn't think I was overstating the Dahlquist. They do some magical things like make sounds come from behind me at times - and they definitely have the ability to disappear in the room when I close my eyes.

And, I did say that the Dahlquist image "almost as well". The Polks definitely do more funny business putting instruments/voices all over the place.

decato

I also have a pair of SRS 3.1tls. They are noticeably more forward sounding than the 1.2tls. There are a few things you can do to make the mids smoother. My recommendations are to reverse the polarity of the tweeter and change the 1.3 ohm resistor in the tweeter circuit to 2.0 ohms. This will reduce the output of the tweeter in the lower range.

I would not recommend changing the large inductor to one with lower gauge wire. There is only one dimensional driver in the 3.1tl. If you change the inductor to one with lower DCR, that single driver is going to exhibit larger excursions than any of the four stereo drivers. The overall limit of the speaker is only as strong as the weakest link. So, yes, you'll get more bass, but the driver will bottom out sooner, and you run the risk of damaging it. I myself use low-DCR inductors, but only in the SDA and SRS models that have an equal number of stereo and dimensional drivers.

If I recall correctly, some early releases of the 3.1tl used a 20-gauge, 18 mH inductor with a 2.0 ohm resistor in series with the woofer. Later releases simply used a 22-gauge inductor. I purchased a mismatched pair and had to order a custom-wound inductor.

Enjoy, they are fun speakers and just the right size for most environments!

gtianz

thank you decato. i really appreciate the advice.

does anyone have recommendations for carpet spikes? Mine have flat plastic feet and I'd like to remedy that issue soon. I'm going to start ordering all the little upgrades like speaker rings and dynamat in the next few days.

I have been searching but short of pulling the speakers to get at the crossovers I havent been able to find a partslist for the 3.1's crossovers. I realize that I should be able to figure this out. But, I must admit that I am ignorant in these regards. i cant remember how to read a resistor based on its color bands.

Is there a simple way to figure out what i need to order to redo the crossovers? I appreciate any help you all can offer.

Schurkey

gtianz wrote: »

I havent been able to find a partslist for the 3.1's crossovers. I realize that I should be able to figure this out. But, I must admit that I am ignorant in these regards. i cant remember how to read a resistor based on its color bands.

Is there a simple way to figure out what i need to order to redo the crossovers? I appreciate any help you all can offer.

https://us.v-cdn.net/5021930/uploads/attachments/1/8/5/1/1/26697.pdf

gtianz

Thank you for the schematic. I printed that out. I was still struggling to figure out the difference between the capacitors and the inductors but, I finally got it when I found the partslist.

Found this with a little more searching:
http://forum.polkaudio.com/discussion/72401/polk-audio-speaker-parts-list#latest

SDA SRS 3.1TL
12uF capacitor
12uF capacitor
24uF capacitor
55uF inductor
1.3 ohm resistor
.3mH inductor
1mH inductor
1.25mH inductor
18mH inductor

gtianz

the 5w mills resisters come in 1.2 or 1.4 ohm. The schematic calls for a 5w/1.3 ohm.

with the rd0198 tweeter im not finding the highs overly bright or over extending. so, im not seeing the need to reduce their output.

Will i see much difference going with one over the other? Which would be suggested?

what is this 750pf capacitor on the schematic? I cant find a sonicap capacitor with a 0.00075uf rating. Am i calculating this wrong?

And based on the inductor wire guage I'm not finding directly comparable options (esp. @22 guage). can these be left as is or will i see improvement replacing them as well?

gtianz

If anyone is curious the thread pitch for the feet it is 1/4-20.

Found a cool little way to check it.

"It is easy to confirm they are 1/4-20 because this is the standard thread used for camera tripods- try to screw one of these into the bottom of a digital camera, and if it threads in easily, it's 1/4-20."

Schurkey

gtianz wrote: »

the 5w mills resisters come in 1.2 or 1.4 ohm. The schematic calls for a 5w/1.3 ohm.

with the rd0198 tweeter im not finding the highs overly bright or over extending. so, im not seeing the need to reduce their output.

Will i see much difference going with one over the other? Which would be suggested?

Doesn't really matter. A tenth of an ohm is negligible. Flip a coin. If it was me, I'd hope the coin landed on the 1.2 ohm option; I like treble. For the record, I installed 10 (or 12...I forget) watt Mills in the HF circuit of my 1Bs. If they have a 1.3 ohm in a higher-wattage resistor, that'd be another option.

gtianz wrote: »

what is this 750pf capacitor on the schematic? I cant find a sonicap capacitor with a 0.00075uf rating. Am i calculating this wrong?

Silver mica bypass cap; not needed when you upgrade to better caps. Forget it.

gtianz wrote: »

And based on the inductor wire guage I'm not finding directly comparable options (esp. @22 guage). can these be left as is or will i see improvement replacing them as well?

I can't help you there. The only inductor I've upgraded is the large on for the SDA system on my 1Bs.

stogie

Jantzen Audio out of Demark has a wide range of inductors.
http://www.jantzen-audio.com/
Don't know if they have what you're looking for but they did have the coils for the CRS+/2B circuit boards. Special order through Parts Express.

westmassguy

stogie wrote: »

Jantzen Audio out of Demark has a wide range of inductors.
http://www.jantzen-audio.com/
Don't know if they have what you're looking for but they did have the coils for the CRS+/2B circuit boards. Special order through Parts Express.

Before ordering, verify what's actually installed on your board. The schematics aren't always correct as far as the gauge and DCR of the Inductors. I found out the hard way with my 2As.
Parts Express can special order Jantzen Inductors, but expect to wait 4-8 weeks for delivery.
Here's the direct link for the Jantzen part numbers: http://www.jantzen-audio.com/wp-content/uploads/2013/04/Air-Core-Coils-List-06-10-2014.pdf

xjghost

Congrats! I wish I could get some of those rings for my 3.1's.

decato

Are you sure you don't want to try the 2.0 ohm resistor in place of the 1.3 ohm resistor? It takes a bit of the edge off.

Also, I should mention if you'd like to hear a bigger soundstage, change the 55 uF capacitor to about half the value -- 27 uF. The 55 uF makes for a pretty sharp rolloff compared to what is used in the larger 2.3tl and 1.2tl models, and it reduces the SDA effect.

I have made all of these modifications to mine and have been pleased with the results.

decato

From reading others' posts, I'm not sure if the effect of the 1.3 ohm resistor is clear. It is in a RC network, not just in series with the tweeter. A value less than 1.3 ohms will make the tweeter have more midrange. A higher value will reduce the midrange going to the tweeter. Upper treble is not affected. I'll have to produce some graphs when I have time.

Schurkey

decato wrote: »

From reading others' posts, I'm not sure if the effect of the 1.3 ohm resistor is clear. It is in a RC network, not just in series with the tweeter. A value less than 1.3 ohms will make the tweeter have more midrange. A higher value will reduce the midrange going to the tweeter. Upper treble is not affected. I'll have to produce some graphs when I have time.

Please do. I think the resistor affects the tweeter level full-range. For example, if there were a zero-ohm "resistor" installed, the tweeter would certainly be louder, and the 12uF bypass cap would effectively no longer be in the circuit.

gtianz

in the list i posted above there is a 55uf inductor. Per Decato's comments and the schematic I believe this is a mistake and it is in fact a 55uf capacitor.

No such beast exist from claritycap or sonicap. The closest i found is 47uf cap from claritycap.

all these small discrepancies from the original specifications is somewhat disheartening. This is a project i want to tackle - But, without knowledge about the impact all the value changes will have makes me hesitant to try it. Throwing $800 at a beautiful completed crossovers for $500 speakers doesnt ring my bell. Similarly, I have had full shopping carts at both soniccraft and madisound websites. There are holes in both carts which has prevented me from pulling the trigger at the $200+ orders.

after 2 days plugging away at the web I am feeling a bit discouraged and overwhelmed.

- - Photography has been a hobby of mine for many years and is something that I am good at. Having a solid understanding of photography principles has always left me scratching my head at those who cant grasp a simple concept like the effect aperture has on the resultant image. I have a feeling this is precisely what is happening here regarding electronics.