I don't think the folks at Polk thought it was a big deal either because they used the same drivers and crossovers in the CRS+ (wide spacing) and the 2Bs (narrow spacing like the 10s). I'm guessing that the CRS had a wide MW spacing so the cabinet would accommodate the PR being mounted on the back side. I'm also guessing that the bigger speakers being wider was a matter of needing to put the tweeters down the center to keep the cabinet at a reasonable height more than the effect it would have on the SDA sound.
Hmmm, that sure is a lot of thinking and guessing. :) Maybe the guys who can hear a fly land on their grill cloth will have a different explanation for differences in SDA MW spacing.
Any ways, At this point, I don't care. I'm just looking forward to see what John does. As Face mentioned already, if someone wanted to even begin doing this RIGHT, there is more than just rebuilding a cabinet...
A great point there KCCO... Let's see what comes of this. Again, the purpose of the thread is to not re-hash what has already been done. Instead I want to focus on design elements, materials, features and other aspects we would like to see in a new SRS-type speaker. Also, I am seeking input from those that have made the SDA speakers that currently exist perform better than when they were new. Surely the knowledge and skill exist here within this forum to come up with a modern form for these classic speakers.
I would think something in fiberglass could hold the same volumes and render the cabinet shapes you are after. My concern is the front vs. back slope. The PR being "fluid coupled" and the drivers being isolated by polyfill, I would think as long as the volume stays the same there should be no real problems with a new cabinet, given the same config for the drivers that is. I wonder how, without having an extremely wide front, you will be able to get the curves or slope front to back that you are after.
You know they will be worth the same as the 7's by the time they are done right LOL.
The only aspect of the front baffle tha can be altered would be the outside edges, and even that gets you only a couple inches. The tapered sides would result in the new speaker being deeper than the existing box by a few inches. I am also looking at the way the feet are designed on the /M's and how such a system could be incorporated into the new cabinets.
First up however are going to be new signature plates for the SDA's I have already. They will be satin nickel finished with resessed signature and other information that the current plates have on them. I will post up pictures of the new plates as soon as I have them, and if I can get Polk's blessing, I will make a bunch of them for whoever may want a set...
I am sorry I have no idea what you are saying here.Quote:
However, If you're going to exclusively reply back and state no, its a bad idea and list 3 of your own reasons why building a shell over the existing OEM cabinet.
My own reasons why building a shell over the existing cabinet what? This does not appear to be a complete sentence and I am unsure what ending you had in mind.Quote:
3 of your own reasons why building a shell over the existing OEM cabinet.
I believe I have described my reasoning in a very basic sense. If you would prefer more detail please let me know exactly which part you would like me to explain in more detail. Again you may want to re-read; I have not mentioned any "facts", but have given reasoning (albeit very general) behind my opinions. And they are only that; my opinions, based on my education and past experiences in and around the audio industry.Quote:
Then why is it you wont elaborate on your reasons... I'm sorry, I mean facts?
Unless you ask for more specific clarification, I will not continue this back and forth discussion past this post, in an effort to prevent things from getting any more heated than they already may be. May you enjoy your Polks as well or better than I enjoy mine.
I just spent the better part of my day adding Larry's rings to the left channel speaker and I must say I am impressed that these speakers deliver so much performance given the shortcomings of these cabinets. The materials used were not the highest grade possible even for back in the day. The particle board is not very good to say the least.
The addition of the rings to the left cabinet has shown there is a significant improvement in sound over that of the right cabinet. I attribute this to the better coupling of the driver to the baffle, and reduced resonance in the driver. I could be wrong on the physics of it.
I am even more convinced ther are performance gains to be made with stereophonic SDA technology by designing a better cabinet. I have some sketches of the new cabinets, and will grab some measurements from the internals when I do the rings on the right side tommorow.
I should have Internet in another week or so and will get the pics on line as soon as I can.
Post up those sketches and I can draw them up 3D.
Then the design ideas can be tweaked in way you want.
When I first got inside my cabinets (SDA SRS) I was really surprised at the 'cheapness' of the internals.
The wiring and the quality of wire is shoddy at best, the crossovers were falling apart.
And the cabinet just doesn't seem beefy enough for the number of drivers that are attached to it.
I'll add that the wire and the wiring is a lot better than you imply and much better than I've seen in other speakers. I don't recall seeing any SDA crossovers that were falling apart either, so not sure why yours would be.
I'll admit, these speakers are very impressive in the way that they deliver performance.
And $3000 back in '86 was pretty steep for the average Joe.
I'm just saying that I was somewhat dissapointed when I got inside them.
The wiring inside is pretty messy and sloppy on the connections.
Who knows, maybe the guy I bought them from did some handy work inside the cabinets.
Original owner, one of my plastic tabs on one the standoffs that hold the inductor to the x-over board on my left speaker was like that too.Also there was the thick paper/felt piece that was suppose to be on the back of the SB radiator lying in the bottom of the cabinet. And yea I paid $2500+tax in 1990 for 2.3tls, which was a lot.
Internal volume is 6.75 cubic feet, including internal bracing.
Why can't one upgrade the drivers and tweeters with better quality ones and just do the math of what values are needed for the capacitors, resistors, and inductors?
I only ask because for one I wouldn't know and two there are a lot of DIYer's that have the skills in building quality DIY speakers..
Why couldn't it be done? Don't throw out the cost to much, in this hobby there is a lot of I don't care what it cost I just want it so I shall have it's...
It's more than just math as far as using new drivers, simulations and measurements would be needed. For an "upgraded" 2B it wouldn't be too difficult, the larger models would be a nightmare unless one went active or stuck with a single tweeter.
Well 2B or CRS+ then. I think the 2B would be easier to work with.
Just a small update here... Next eek I meet with a professional cabinet shop about these speakers. This shop is the west coast vendor for factory finish repair for B&W and a few others, as well as doing grand piano restoration. This should give me an idea as to cost. I won't even begin to take this on if I cannot take it to a very high level of finish quality. If these are to have any life at all, I want them to be something that Mr. Polk would be proud to stand next to in his famous white labcoat.
Do it right or not at all on these. That served me well on the amps so lets see what happens.
AMEN brother, I agree. Can't wait to see what happens with these, I have thought about the same thing for years now.
Finishing costs on these will be around 2500.00, but for that money, these speakers will be world-class "production ready" speakers that incorporate the latest in cabinet construction and of course, all current upgrades and modifications.
Magnetic grills are also in the works for these.... It will be a long journey from here on, but I am pleased to say that the idea is a go!
Anyone that wants to bring their skills, ideas and talents to the fore, and help me bring them to life, shoot me a pm or post your intentions here. There will be a new thread when the build begins.
Coming in 2014, the SRS/M!