My SRS Refurb project

GospelTruth

markamerica wrote: »

Here are the hastily prepared .jpgs of the idea. (I can just hear the cringing.)



Okay, this is what happens when one has a free Saturday morning to relax for a bit. Don't hate me...

I may be wrong here, but I always thought that the design of SDAs had the mids side by side in two columns because that was the "distance between the ears" on a humans head. That was how the SDA effect worked because of that arrangement. Based on your configurations, wouldn't putting two mids next to each other, then a tweeter and then two dimensional mids ruin the creation of the SDA effect because you would be moving things out further from each other with that configuration?

Like I said, I could be wrong on that one, but that was my understanding. Guess we'll find out once you make them. I'd hate for you to go through the whole exercise though only to find out that it won't work because of that physical requirement. I'm not against what you are doing, as it actually looks pretty cool. Maybe some of the other SDA gurus can chime in on that one and correct me if I'm wrong.

markamerica

You're correct, GospelTruth. That's why I was playing with angles and steps and so on, in an attempt to compensate for this, trying to find an arrangement that would still work at the optimum listening position in the room. I may never make them if I cant figure out an arrangement that seems to hold some potential to accomplish what you've stated. What the notion I was counting on is that two side-by-side mids, playing the same exact same signal, will seem as one mid with the sound originating approximately from the midpoint between them. Changing the angle of the face of the front baffle was intended to make those points with respect to the stereo and dimensional pairs seem to converge enough to make the lines roughly parallel, preserving the SDA effect. The problem I was running into with the very first picture is while it seemed it might accomplish that with the stereo and Dimensional pairs, the tweeters dispersion might well leave a hole at precisely the optimum listening position. In short, with the tweeters toed-out, if you think about the sound they're producing as emanating in a cone, that cone is too narrow to cover the optimum listening spot in the room. Not good. So then I was discussing step arrangements of the front baffle with Westmassguy, in an attempt to preserve the narrowing of the distance between the stereo signal and the dimensional signal while addressing the tweeter dispersion issue. After playing with that last configuration, it became clear to me that this wouldn't work either, because while correcting the tweeter issue, it reintroduces the problem with the SDA effect. So at this point, I have no solution. What I will wind up doing is a much more detailed drawing, taking actual measurements in the room to see if there is any plausible configuration of the drivers which will both a.) work within the confines of the space limitations and b.) meet the intended goal of making the speakers work correctly as heard from the optimum listening position. If I can't accomplish that,they never get built.

Thanks! Mark

drumminman

Mark, your well considered posts with all the thought you've put into this project has me realizing how much I don't know about SDA technology! Great food for thought.

markamerica

Drumminman, Thanks! Thing is, there are those reading my ramblings who are now firmly committed to the notion that I don't know anything about SDA technology, and they could be right...LOL It's all fun. I like the challenges. It's why I wanted so badly to try out my custom center: Can it be done and sound reasonably correct? Apparently, yes. My SDA-1B.BSs may never get off the drawing board, but it's fun to play with.

Thanks again!

Mark

Mr. Bubbles

markamerica wrote: »

Mark

If i am understanding you correctly; The stereo drivers (side by side) inboard and the dimensional drivers outboard (side by side) with the tweeters in the center (stacked on top of each other) then below is how I percieve what you will really have.





You will not have a minor time alignment issue. You will not be killing the SDA effect due to the baffle angle (although it will definately hurt it). You are aligning the dimensionals beside each other in a horizontal plane and the same with the stereo drivers. You now have 2 horizontal sources for each signal on each side of your head. This creates 2 vertical planes of origination for each signal on each side of your head. This is not even considering the tweetwers or crosstalk signals that you have now , not only not cancled from killing the SDA effect, but added to due to adding the other source points along your horizontal listening plane.

This would work much beeter using components such as the 2's would have instead of the 1's. Cut the drivers down and cut down the source points. Now imagine image below. This stuff works because of time alignment. It works, not due to the angle of the lines, but the length of those lines. Notice the lines (angle and length) with the multiple horizontal source pints removed. This is why the drivers were stacked in the original designs.




I'm not hating, just pointing out what I see. Either way enjoy and hope you like what you end up with.

markamerica

Mr.Bubbles,

I had considered just using 2B innards to accomplish what you describe. Like I said, this is drawing-board speculation/mental contortions. I was hoping that with the drivers side-by-side, the ears/brain would perceive them as a single point, each pair, but I must admit I see the logic in your description. A flat-faced 2B arrangement would certainly be easier to engineer. And I do have a set of 2Bs not currently in use. (Muhahahahahaa!)

I didn't really think anybody would be "hating." I was just being a goofball.

Mark

Mr. Bubbles

I almost forgot; My grandmother taught me a trick to "train" cats, many years ago. Cayenne Pepper! Put a little in your spray bottle and sprinkle it anywhere you dont want them hanging around. Once they are sprayed with it a few times they will start noticeing the smell in areas you have sprinkled it. Viola!

markamerica

As long as it doesn't cause harm...much... May give it a try.

Thanks!

Mark

Mr. Bubbles

I never saw it cause any harm. But the cats stopped going near anywhere it was. Abaout as devilish as I ever saw my grandma get. It made her feel sneaky becasue she was outsmarting the cats.

Me on the other hand, I like catching the cats and wrapping their feet in tinfoil and watching them walk around. or tying helium filled ballons to their tails and watching them try to get away from them. I'm really surprised my wife married me after seeing the way I tormented her cats when we were younger. I guess I've bored with it as I got older.

markamerica

Mr. Bubbles wrote: »

Me on the other hand, I like catching the cats and wrapping their feet in tinfoil and watching them walk around. or tying helium filled ballons to their tails and watching them try to get away from them. I'm really surprised my wife married me after seeing the way I tormented her cats when we were younger. I guess I've bored with it as I got older.

We'll be keeping an eye on you...

Mr. Bubbles

This post has made me curious. How big is youre room? It would seemingly be HUGE with 1.2TL's behind you and SRS in front. man I wish i had that kind of space. i would prob set up my HT using my gear like you have.

markamerica

No Mr. Bubbles, my room is not huge. That said, as I mentioned in another post, I am accumulating/building what I want for the day when that condition changes. My intention is to play these speakers at sane levels given my environment of the present, enjoying them thoroughly, while planning for the day the room that houses my gear will be one that had been purpose-built around them.

TNTsTunes

I've did some experimenting today in a 24' wide by 30' long theater room. My friend just moved in, but doesn't have a decent stereo, so I asked if I could setup there for a few days or so...

I took over my SRS 2.3's, SDA2A's, an Adcom 5802 and a 5500. I also took one M10 for a center channel and a Yamaha DSP1A as the brains. I took my sub too.

What I found worked the best was surprising. I have the SRS 2.3's 5' off the side walls in the front and the M10 centered(powered by the Yamaha).

I was sitting 12' back in the room viewing "The Watchmen" as a test disc among others.

By putting he SDA2A's against the side walls, facing each other, the stereo drivers toward me and 7' off of the back wall it really changed the sound stage. It added depth and great separation while smoothly blending together with the front. There is a leather couch between them also.

It was almost like the rear soundstage just picked up as the front sound stage just ending. Overall the rear soundstage was clearly separated with a wider and deeper soundstage.

The M10's gain was run at -15db since the 2.3 SRS's do such a good job up front.

I just wanted to see how my system sounded as a 5.1 system since I've never tried it with the 2.3's or in a good room.

I'm sure the seating on the back sucked, but the sweet spot was real nice for 4 theater seats.

It was a surprising to find it sounded very nice setup that way.
It goes back to a two systems listed in my sig soon.

markamerica

TNTsTunes,

The SDAs can produce an excellent theater effect. I'm really looking forward to the day I can move all of mine into a room optimized for their virtues.

Back to the SRS refurb, the PathAudio resistors arrived today, and I picked up my aluminum pieces for the backside of the crossover plates, on which whatever board arrangement I choose will ultimately be mounted.

Piece at a time, right? 20 tweeters due in tomorrow.

Mark

markamerica

Hurrah! I'm having a tweeter replacement party this evening! 20 won't replace all of them, but it's a good start.

markamerica

I decided that the SRSs and the center were enough for tonight. Did some direct before/after comparisons. The RDO-194s are definitely a huge upgrade from the SL2000s. This definitely should be the first upgrade on everybody's list.