Inventor Outdesigns Matt And Team!!!

[BobMcG]

This fellow is convinced he out did, out engineered, out smarted, and just plain out designed Mathew Polk and team.

When he was emailed as to why he would do such a thing to these speakers he said it was because the speakers had no bottom end.

He did say he was including the PRs in the sale though just in case someone wanted to go back to having no bottom end. ;) :D

Did these go to any Polkie in here by any chance???

Bottomless SDAs

[nadams]

i think they've been for sale before. could've been some others, though .I've seen quite a few polks with the PRs replaced by active drivers... must beat the hell out of the midrange drivers.

[BobMcG]

I'm never looking so this is the first set done like this brought to my attention (by my brother). Matt and the others must feel so silly now! :o

I guess it takes all kinds. :)

I think I'll just cut a big hole in the back of mine and install a another PR for double the radiating surface area. Yeah, take that Matt! :D

[F1nut]

And yet he still quoted Polk, "The use of 8 small active drivers coupled to the large 15" sub-bass radiator results in extraordinarily tight, quick and three dimensional mid and upper bass combined with low and sub-bass capabilities which are staggering (clean output at 25 Hz exceeds 100db!)"

Nah, they don't have any bottom end.

[ledhed]

He misspelled aficionado. I don't want to buy from someone who doesn't know what spell check is

[Frank Z]

He ruined 'em.

[StinkyDog]

Yeah I saw those too when I was researching prices for my SDA 1Cs. They sold in like 11 hours or something. Regardless that he changed out the radiator, $750 is a hell of deal for those I think.

[polkgrinder]

Hey guys, nice to be a part of the Polk Forum. I purchased the speakers with the active bass. The seller has the original passives and I plan to try both set ups. The seller is increadibly nice with tons of advice. Great person to converse with and get to know. Furthermore, he had chosen to go with actives because of low frequency hearing loss. I don't blame him and why not!! It will be interesting to hear the difference of the two combinations verses each other. I will let you know of my final tastes. Furthermore, I am glad that I finally found a pair that I could afford and not face shipping and handling charges!! The last time I heard those speakers was back in the day when were taller than me!! My hearing was perfect back then and I was blown away!! But at the time, I had to stick with my hand me down ESS's and Phase Linear Amps because my paper route just could not pull in the income to buy a brand new pair of monsterous Polks! LOL!!

Nice to be a part of the forum. I will be seeking advice on speaker/amp/preamp set up and tweeter replacement. For now, what would you recommend for replacing the covers? I prefer the original black. I have time to clean them up and go over the cross overs and tweeters while I shop for amps.

Nice to be back in the POLK world after all these years!!

[hotwheelman]

Do those speakers a favor, ditch the frankensten active crap, reinstall the passives and stick to the program....you'll be glad you did. Just my 2cw.

[F1nut]

Clean bass down to 25Hz @ 100dB with the original PR's. If he couldn't hear that those active drivers weren't going to help.

Congrats on your new SDA's and welcome to the forum.

[VR3]

Its not really a matter of hearing loss... the passive radiator is meant to move with the midbasses, not the passive radiator help move the midbasses... (which the active would be doing)...

Its just a bad idea...

[TroyD]

Hey whatever floats your boat, they are your speaks.

Enjoy and welcome.

BDT

[BobMcG]

I know who built the "Franken Polks" (his name) I know about his hearing loss, he used to frequent my brother's and my site and he's not a "bad man". He's just a "Mad Man". You don't do that to these speakers period. It's not how they were designed to work properly.

But..... do what you want. Go ahead and out design Matt and the crew.

[autoconsortium]

The active sub is a horrible idea. The SDA cabinet is sealed, and uses the passive radiator to release tight bass in conjunction with the array of midrange drivers. Adding a 15 inch woofer that bounces around disrupts the entire design, and will most certainly mess up the response characteristics of the 8 midrange drivers. If you are going to keep this 15 active sub, you might as well cut a port hole in the back, and undo the entire SDA imaging (thereby ruining the entire effect of these speakers), so the 8 mid's all play simply the midrange for that speaker.

[Dennis Gardner]

Yeah, replace all the tweeters with new ones that change the original sound, rebuild all the crossovers with different brand parts that change the sound, replace all the internal wiring with different brand/gauge, upgrade the binding posts, upgrade the SDA cable, damp this inside of the box, but don't you dare touch that PR.

Look guys, I understand the physics of the design, but I imagine that unless someone has spent alot of time around here, we look like a bunch of hypocrites to newbies. :D

[puunda]

I'm still not sold on the SDA idea, and I'm not sold on the PR idea ... but that's another topic. With regards to this, I didn't think you could do that. Doen't matter how they sound, I would've thought replacing the PR with a 15" sub would pop the 6.5" drivers right out of the cabinet.

[Dennis Gardner]

I would've thought replacing the PR with a 15" sub would pop the 6.5" drivers right out of the cabinet.

It can in sealed systems if the driver had alot of travel and only one open back mid was used, but if the 8 mids can move a PR on their own, they could handle the movement as well. Its about moving air and 8 six inch models will easily move as much as 1 15". The SDA was designed from the start as a PR design and using it as a sealed active bass model successfully requires way more change than dropping in the driver and running wire to them.

[BobMcG]

Yeah, replace all the tweeters with new ones that change the original sound, rebuild all the crossovers with different brand parts that change the sound, replace all the internal wiring with different brand/gauge, upgrade the binding posts, upgrade the SDA cable, damp this inside of the box, but don't you dare touch that PR.

I fail to see a logical comparison presented here. It's more like apples to oranges.

[Dennis Gardner]

I fail to see a logical comparison presented here. It's more like apples to oranges.

My point was, tweeks are tweeks to anyone without the knowledge.

Furthermore, he had chosen to go with actives because of low frequency hearing loss. I don't blame him and why not!!

The purchaser is new to Polks and needs to understand the physics of the design to know the difference, otherwise we look like elitest know-it-alls with our improvements over Matt's design, but critics of others changes.

[BobMcG]

Tweeks are tweeks, upgrades are upgrades and neither are attempts to "redesign" the speaker.

I don't know of any of us in here who have "redsigned" our SDA speakers.

[madmax]

You can do anything to anything. Kinda like putting a ford motor in a chevy. Welcome to the forum! I think you will see the beauty of the original design if you re-visit it.
madmax

[polkgrinder]

Hey guys, I picked up those "Frankenstien" speakers and played them Sunday. I installed the PR's and the speakers sound good eventhough two or three tweeters are shot!! The actives were doing some weird things with the speakers and they had too much bass with my current system. Thus, back to the PR's. The previous owner ran the speakers on tube amps and loved strong bass, hence the actives and the 24 inch subs in his house!! I hooked the speakers up to a vintage Marantz pre and two Phase Linear 400s in bi-amp mode. The meters barely register on the amps and the speakers filled the room. Great soundstaging. I am surprised at the efficiency of the speakers!! They are way better than some vintage tower infinities my brother had years ago and two Phase Linear 700Bs could barely make them register! But hey, they made a nice dimming light show in the house every time there was a bass note!! But the Polks seem weak in the highs and upper midrange. I believe it has to do with the tweeters and they need some work. I have not opened them up to see if they are even recieving current or if the tweeters are just plain fried. Furthermore, I don't think they are 1.2's either, they have a manufacturing date of 1986 on the PR's. I will check all the drivers to see if they are all 6503's and if so, I believe that would make them the original SDA's.

Anyways, interested in the upgrades of the cross overs and tweeters. I know I can order the newer tweeters, but I hear so many different upgrades for caps and resisters on these speakers and I am wondering which route to take or if anyone can lead me to some reading about it?

Thanx guys. Love to hear your responses and ideas on upgrading these speakers.

Great to be a part of the forum. I will be updating you guys of the speakers progress back to normal conditions. They need some cabinet work too!! The wood tops are splitting! Time to find some wood working tools and quality wood glue.

[F1nut]

Until you have all the tweeters working, you really have no idea what the speakers sound like or are capable of, so start with replacing them.

[BobMcG]

Until you have all the tweeters working, you really have no idea what the speakers sound like or are capable of, so start with replacing them.

+1. The best place to start.

[keith allen]

Well,I would like to hear them...Detroit rock city baby!