SDA 2B Upgrades - Part 1

GospelTruth

Well, after a couple of months of listening to my SDA 2Bs, I decided to start down the upgrade path. It helped that I ordered Larry's rings as they were just sitting there, practically begging me to install them and "hear" the difference.

Upgrades
Part 1 of my upgrade path was to do some of the "cheaper" modifications first. They are as follows:

• Install Larry's rings for a better coupling of the drivers to the speaker cabinet (Cost: $74 including shipping)
• Install Dynamat to the driver cages to cut down on any resonance that might affect the drivers and passive radiator. (Cost: $29 on Amazon, only used half)
• Install J-B Weld to the driver magnets to "insure" that they won't shift. (Cost: $5 at Home Depot)
• Install Amacell around the edges of the drivers to perform a tighter seal with the cabinet to prevent air leakage. (Cost: $8 at Home Depot)

Tear down:
First, I had to remove all the drivers and take pictures to document the wiring.

Larry's Rings:
The first order of business was to install Larry's rings. I tried reading up about them and how to install them correctly. I found some good posts, but I am posting some other pictures for anyone wanting know to about their installation. I was a little nervous at first drilling into the cabinet and making bigger holes where the screws had previously secured the drivers to the cabinet. Any fears were put to rest when I started drilling and the installation process. I had to look around though to find a 9/32" drill bit as it wasn't one of the more common drill bit sizes I had sitting around. But once I found that size, it was easy going from there. The templates provided by Larry made easy work of the drilling. Once all the cabinets were drilled out, the rings were installed from the inside of the cabinet. They fit well and I only had one section that had excess glue in the cabinet that prevented a driver ring from pulling flush against the cabinet. That was fixed using a small wood chisel and a utility knife. At that point, all the rings were installed without a hitch. Thanks to Larry for providing this service for Polk members. These rings truly are precision made for these speakers. Great work!

Installed Ring

Dynamat:
I then proceeded to start the installation of the Dynamat. I found a couple of posts that had pictures on how folks installed the stuff. Thank goodness for pictures because I had no idea where to put this or what it was even for when I first joined the forum. It took a lot of measuring, cutting, pealing and sticking of this tar/aluminum substance to complete everything. Holding up a driver that was completed and one that was not I could definitely tell that the driver cage had less resonance than before when I tapped them. Hey, it sounds like it's working so let's hope it helps with the sound later on!

J-B Weld:
I had read about this but hadn't actually known want to do until I did some more research on this one. I finally understood where to use this stuff to prevent any magnet shift issues that could arise. The drivers were out anyway so I figured why not perform this little task just as an insurance policy as others have said as well. No sonic improvements with this modification, but there is peace of mind. I did wait 24 hours for the stuff to dry.

Armacell:
So, upon removing the drivers from the cabinet, I pulled back the factory foam seals around each speaker. They were definitely pretty thin compared to the Armacell I had purchased. In fact, the Amracell looked so thick, I didn't even know if the drivers would be able to be re-installed. I thought they might not sit down flush with the face of the speaker after installation. I cut the 2" wide strip into 4 strips length wise. In the end, I had 1/2 inch strips that I installed around the edge of each driver where the previous seal had gone. The 1/2" strips worked perfectly as far as the width. Once completed, I installed the drivers and used the bolts that came with Larry's rings to secure the drivers, tweeters and passive radiators to the speaker boxes. The extra width of the Armacell was not an issue with Larry's rings. Final installation was a breeze and secured the the drivers to the same position they were prior to the upgrades.

Removal of the factory seals

Replacing with the Armacell

Installation:
Some pictures of installation of mods and the final product.

I took pictures every step of the way and I'm glad that I did. It sure helps to go back and look at how things were connected before I took everything apart. Without that, I'm sure I would have been in trouble. Digital cameras are one of the great advantages don't you think?


Before/After comparisons.
Now, I haven't listened to these speakers year after year like some have on the forum. Nor do I profess to be able to tell minor differences and nuances with some of my CDs. I've been trying to listen as best as I can so that after the upgrades I could make a comparison. I consider myself someone who can definitely hear the differences between speakers, but sometimes small changes are wasted on me. For instance, different brands of speaker wire - I am probably not your man when it comes to being able to tell differences. I'm not looking to start a discussion on that topic, I just want you to know where I'm coming from. With that here are my impressions with these upgrades.

Before performing these modifications, I did feel that the speakers were a little shy on the bass. Not that they sounded bad by any means, they just lacked a little punch that I thought should be there. I chalked that up to the way the speakers were designed. I've had the speakers about 1" away from the walls to maximize the bass. My room is about 15"x19" just so you understand my room size in relation to my perceptions. Before the upgrade, I did the "push" test on the passive radiator to see how long it would take the two drivers to relax and fall back to normal. It would typically take between 3-4 seconds to do that. After the upgrades, it now takes about 8 seconds for them to fall back down, but that is about 90% of the way. They take even longer to fall back completely. I don't know if this is a good thing or not, but it confirmed to me that the cabinet was definitely not leaking air like it was before. I credit Larry's rings and the Armacell for that.

Once completed, I could hardly wait to get them hooked back up to see if there were any differences that I could hear after these upgrades. From the Don Henley CD, Actual Miles, I played "Sunset Grill". The beginning of this song has some nice drums that pan around. Immediately I noticed that there was a punch to the bass that was missing before. At this time the speakers were approximately 8 inches away from the wall. They were further away from the wall and still had more punch than they did before! The difference was definitely discernible. Additionally, the mid range presented a fuller sound. I wouldn't have noticed that it was missing before until these upgrades were installed. The mid range had definitely improved. The high end was the same as before, but I wasn't expecting much of a change there. Voices and instruments did sound more focused within the sound stage, but not to the same level as the bass was increased. At this point, I can't say that the sound stage increased or not. That sounds the same to me at this point. Probably further listening will tell if I notice any change there.

All in all, it was worth the effort. These speakers have definitely improved from what they were before. I have yet to perform a crossover upgrade or replace the tweeters with RDOs. From what I've read, those changes will further enhance these speakers even more. I love what I'm hearing though and highly recommend these initial upgrades.


Special Thanks
I would like to thank everyone on this forum for pointing out all the possibilities and how to perform these upgrades. I would especially like to thank Larry (Toolfan66) for designing and creating the rings to secure the drivers to the cabinets. I would also like to thank F1Nut, Heiney9 and DarqueKnight for all their knowledge and detailed posts. I'm sure there are others as well, but these guys sure put in a lot of effort and pass that knowledge on to the rest of us. And thanks to everyone for contributing to make this site what it is - awesome!

StuartB

Nice job! I am with you....doing the work yourself is very rewarding. I recently did the mods you document and I also rebuilt the crossovers in my Monitor 5b speakers. I also ended up upgrading the tweeters as well......something tells me you have the bug, and will make the additional upgrades shortly. Enjoy!

TennMan

Very impressive writeup. Professionally done with great information and photos. I look forward to reading Part 2.

Conradicles

Good job! I noticed the same findings with my rings installed.

nspindel

First off, let me say that those are some really nice looking 2B's you've got there. The cabinets and end caps look like they are in great shape.

One thing you should know, though, is that 2B's absolutely shine when the TL-mod is performed to them. That would allow you to use a RD-0198 tweeter, which can run circles around the SL2000. I highly recommend re-doing your crossovers and doing the TL mod. At the least, if you're not looking to touch the crossovers, swap the SL2000s out for RD-0194s, which don't require any mods to use. If you do your crossovers, try to get hold of a pair of Gimpod's boards.

Crossovers, inductors, and a Dreadnought. That is my advice to you as you continue on your way. Great job and congrats!

StuartB

nspindel wrote: »

First off, let me say that those are some really nice looking 2B's you've got there. The cabinets and end caps look like they are in great shape.

One thing you should know, though, is that 2B's absolutely shine when the TL-mod is performed to them. That would allow you to use a RD-0198 tweeter, which can run circles around the SL2000. I highly recommend re-doing your crossovers and doing the TL mod. At the least, if you're not looking to touch the crossovers, swap the SL2000s out for RD-0194s, which don't require any mods to use. If you do your crossovers, try to get hold of a pair of Gimpod's boards.

Crossovers, inductors, and a Dreadnought. That is my advice to you as you continue on your way. Great job and congrats!

Could you explain what the TL mod is, and then what the Dreadnaught mod does? I have seen the Dreadnaught upgrade in some recent threads, but I am not sure what it is and does, and then what models benefit from it.

Thanks

nspindel

Hi Stuart -

Lots of write ups on the forums about this topic, but I'll give you a brief overview:

TL Mod - Involves the addition of a 5.8uF capacitor in the crossover circuit for certain model SDA's, of which the 2B is one of them. This allows the substitution of the SL3000 for the SL2000 tweeter, or in current replacement terms, you can use the RD-0198 instead of the RD-0194. So it allows you to use a better tweeter.

Dreadnought - SDA's are meant to be used with common ground amplifiers. In the case where your amp is not common ground, i.e. mono blocks, there are certain model SDA's, again the 2B being one of them, where you can use a replacement SDA cable called an AI-1, which has an isolation transformer between the left and right sides. A Dreadnought is basically a replacement for the AI-1, with a massive isolation transformer. Recent tests are showing that a 1000VA Dreadnought (or an 800VA for that matter) improve the sound quality over a direct SDA connector even with common ground amplifiers. So there are a number of people who have jumped on that bandwagon.

If you're interested in doing up a Dreadnought, I'm putting together a group buy for the 1000VA transformers, feel free to jump in because we still need a few more people to commit before we can order. Have a look here:

http://www.polkaudio.com/forums/showthread.php?134643-Group-buy-Avel-Lindberg-1000VA-isolation-transformers-for-DreadNought

drumminman

+1 on the Dreadnought - one of the better tweaks I've done.

StuartB

Thank you. I actually did search and found lots of discussions but not the underlying definitions.....maybe I did not go back far enough, but anyway, thanks for taking the time to explain....especially on teh TL mod to use the better tweeter.

nspindel wrote: »

Hi Stuart -

Lots of write ups on the forums about this topic, but I'll give you a brief overview:

TL Mod - Involves the addition of a 5.8uF capacitor in the crossover circuit for certain model SDA's, of which the 2B is one of them. This allows the substitution of the SL3000 for the SL2000 tweeter, or in current replacement terms, you can use the RD-0198 instead of the RD-0194. So it allows you to use a better tweeter.

Dreadnought - SDA's are meant to be used with common ground amplifiers. In the case where your amp is not common ground, i.e. mono blocks, there are certain model SDA's, again the 2B being one of them, where you can use a replacement SDA cable called an AI-1, which has an isolation transformer between the left and right sides. A Dreadnought is basically a replacement for the AI-1, with a massive isolation transformer. Recent tests are showing that a 1000VA Dreadnought (or an 800VA for that matter) improve the sound quality over a direct SDA connector even with common ground amplifiers. So there are a number of people who have jumped on that bandwagon.

If you're interested in doing up a Dreadnought, I'm putting together a group buy for the 1000VA transformers, feel free to jump in because we still need a few more people to commit before we can order. Have a look here:

http://www.polkaudio.com/forums/showthread.php?134643-Group-buy-Avel-Lindberg-1000VA-isolation-transformers-for-DreadNought

nspindel

Basically, "TL" is just something that Polk started appending to the model names of the later generation SDA's. On certain older models, the crossover just needs one simple cap in order to be equivalent to the TL-generation models, and then you pop in the better tweeter. That's why people sometimes call the modded 2B's "2B-TL" after they're done, because people understand what it means. There are real Polk model names that contain the same nomenclature, like the big boy 1.2TL's. Those came from the factory with the SL3000 tweeter.

GlennDog

Nice write-up! . . . and please consider getting on The Dreadnought band wagon!!

G

TNHNDYMAN

very nice write up, I plan on doing most of the same mods very soon.

michaeljhsda2

Very nice write-up. I did the TL mod on my 2B's and it made a substantial improvement in sound quality. Another consideration is to install spikes.

GospelTruth

nspindel wrote: »

First off, let me say that those are some really nice looking 2B's you've got there. The cabinets and end caps look like they are in great shape.

One thing you should know, though, is that 2B's absolutely shine when the TL-mod is performed to them. That would allow you to use a RD-0198 tweeter, which can run circles around the SL2000. I highly recommend re-doing your crossovers and doing the TL mod. At the least, if you're not looking to touch the crossovers, swap the SL2000s out for RD-0194s, which don't require any mods to use. If you do your crossovers, try to get hold of a pair of Gimpod's boards.

Crossovers, inductors, and a Dreadnought. That is my advice to you as you continue on your way. Great job and congrats!

Yes, the speakers are in pretty good condition. The sides are coming off near the top and bottom of the speakers, so I plan on removing them, tightening any speaker cloth and then securing them back to the speaker with some liquid nails. I've been thinking about removing end caps and replacing them or finishing them with a high gloss black paint. I've seen a picture of it and it looks pretty amazing. Speakers sometimes just sound better when they look top notch. For me, it's kinda like having a nice sports car. It may be fast, but it's always "faster" and drives better when it's cleaned up, polished and looking good.

I've been pretty skeptical about doing some of these mods and wondering if I would really be able to hear the differences. Well, so far, I totally can tell the difference - and I wasn't trying to listen for it. My next plans are to redo the crossovers and get the RD-0198 tweeter. That may be a little bit though as that will require additional funding and there are other things that are taking priority right now. Additionally, at some point, I'm going to look for a better amp than what I have with my current receiver to drive these things. I'm sure that will help out as well.

Right now, I'm simply enjoying the journey.

GospelTruth

michaeljhsda2 wrote: »

Very nice write-up. I did the TL mod on my 2B's and it made a substantial improvement in sound quality. Another consideration is to install spikes.

Ah yes, another thing to consider when I redo the end caps is to put on some spikes! I almost forgot about that one. Thanks for the reminder.

GospelTruth

Did something happen to this thread or others where the pictures were somehow removed? I can't edit the thread either to attach them again either. Any thoughts?

nspindel

Same thing happened to me in other threads. Not sure what the issue is

F1nut

I can see your pictures.

drumminman

I can see the pics, but when I click on them to enlarge the dialog box opens but not the pics.

F1nut

drumminman wrote: »

I can see the pics, but when I click on them to enlarge the dialog box opens but not the pics.

Ah yes, I get the same thing.

There was a problem with the pictures downloading a few days ago and Patrick fixed that, but obviously something is still amiss. I'll let him know.

GospelTruth

F1nut wrote: »

Ah yes, I get the same thing.

There was a problem with the pictures downloading a few days ago and Patrick fixed that, but obviously something is still amiss. I'll let him know.

Hey F1, did you ever hear anything back about the issues with pictures not showing up? Just wondering as I still can't see the images I loaded for this thread. If it can't be fixed, I might have to just add another post and reload the images as I can't even update my original post.