the next sda srs 1.2 tl

PolkieMan

Now this is the guy to it if it is going to be done right.

DarqueKnight wrote: »

SDAs are not conventional speakers and conventional speaker design math will not yield accurate results. You must consider that SDAs are, in effect, two speaker systems in a single cabinet. A lot of thought and experimentation went into the optimal arrangement and spacing of tweeters, drivers, and passive radiators. This is not a project I would attempt without powerful computer simulation tools that would allow me to build a mathematical model of the stock speaker and then allow the calculation of the overall effect of making changes to numbers of drivers and their positions.

The crossover calculations alone would be a nightmare to do by hand.

scubasteve4sq

I don't think anyone here could. Maybe not even Matthew polk himself. There was tons of money, trial and error over the years, teams of engineers. Its just not possible.

Mr. Bubbles

DarqueKnight wrote: »

Dunlavy and Duntech speakers used doped paper mids and woofers, cost up to $35,000, and are considered among the most accurate loudspeakers in the world.

Stereo Review said this in their November 1985 review of the SDA SRS:

"The results of our bass-distortion measurements were both expected and surprising. Expected, because the huge bass radiating surface should generate very little distortion since only a small cone displacement is required for a given output. Surprising, because we have never measured a low-bass distortion level as low as that of the SDA-SRS."



Polk could have used more expensive drivers with plastic cones. They chose doped paper for a reason. Most probably the same reason that Dunlavy and Duntech chose doped paper drivers: they thought they provided more natural and realistic sound. I'm not saying that "better" drivers weren't available when considered solely on a specification basis, but what is actually "better" is what comes closest to meeting sound performance goals.




It appears that Polk addressed this. This is from a TL series brochure:

"Additionally, the SRS 1.2TL and 2.3TL utilize Polk's Progressive Point Source technology to maintain a Constant Vertical Directivity of mid and high frequencies, which prevents undesirable beaming. As frequencies increase, the tweeter array adjusts its radiation area and eventually becomes an ideal point source at the very highest of frequencies, eliminating frequency interactions and reflections between multiple drivers."

I appologize that i am not as adpet at multiquoteing as some thus making a reply like this mor edifficult to follow.

I know nothing of Dunlavy and Duntech and little about the Sonus faber models you mention later in the thread. I have no doubt that doped paper sounds natural and can be a great material. Even in the vintage Polk models. My knowledge od doped paper indicates that just as there are many differing grades of metals, plastics and other materials there as also differing grades of doped paper. This is based on the types of fibers used and the dopeing compound. I am not 100% sure but I assume that the speakers you mention do not use the same basic fibers as the vintage Polks. In fact the list of speakers you have for the Sonus Faber models indicate as much. Please refer to the driver details of the models you indicate. materials such as carbon fiber and paper blend, blends of multiple types of pulp fibers, foam, etc are are described as materilas for the mid/ woofer cones in these models. No mention of what the doping material may be that I was able to find.

I personally enjoy doped paper cones and have never heard many good quality drivers utilizing them that I did not enjoy at least somewhat. That just does not make them the best technology in many cases, but better fibers, the use of composites, etc can easily make them much, much better than basic doped paper drivers.

Now to your final point; Polk only addreessed the "Progressive Point source Technology" in the tweeter array. Though i believe this to be a vast improvement over what it may have sounded like in a system not utilyizing this technology, it still does not provide the source point accuracy of a single driver.

Mr. Bubbles

DarqueKnight wrote: »

SDAs are not conventional speakers and conventional speaker design math will not yield accurate results. You must consider that SDAs are, in effect, two speaker systems in a single cabinet. A lot of thought and experimentation went into the optimal arrangement and spacing of tweeters, drivers, and passive radiators. This is not a project I would attempt without powerful computer simulation tools that would allow me to build a mathematical model of the stock speaker and then allow the calculation of the overall effect of making changes to numbers of drivers and their positions.

The crossover calculations alone would be a nightmare to do by hand.

This exactly!

Mr. Bubbles

CLUBCARRERA wrote: »

all I wanted to know is how to add or wire two more tweeters into the tweeter array like for tweeter 5 use this cap and coil but no one has stepped up ! to tell me .look I am 50 years old my hearing not the best all I am trying to do is building my dream speakers I care less if there not to everyone like or sound but I do care about building them right (giving it my best shot) for my ears and listing taste the speaker to me that sounded good were the speakerlab 7 here are my crossovers boards so far that I have designed

Though I am not a fan of your idea, I admire your desire to perform this project and see what happens. I wish you luck. Though i do not think I would be pleased with the outcome of such a project, I hope you are able to create what you are searching for and are happy with your build when it is finished.

DarqueKnight

Mr. Bubbles wrote: »

I am not 100% sure but I assume that the speakers you mention do not use the same basic fibers as the vintage Polks.

I think that is a safe assumption. However, my point was not that there have not been advances in driver cone technology since the heyday of the SDA series. My point was that we can't assume that a doped paper driver in inherently inferior and more prone to high distortion. That is why I pointed out that some of the most accurate, most acclaimed, most expensive speakers used doped paper drivers. That is also why I pointed out that the ancient SDA SRS's drivers had very low measurable distortion.

Mr. Bubbles wrote: »

In fact the list of speakers you have for the Sonus Faber models indicate as much. Please refer to the driver details of the models you indicate. materials such as carbon fiber and paper blend, blends of multiple types of pulp fibers, foam, etc are are described as materilas for the mid/ woofer cones in these models. No mention of what the doping material may be that I was able to find.

Sonus Faber does not give specifics on the doping compound they use. That is probably proprietary information. They only say:

"To further inhibit any residual cone coloration we are using a transparent viscous surface damping coating."

Mr. Bubbles wrote: »

I personally enjoy doped paper cones and have never heard many good quality drivers utilizing them that I did not enjoy at least somewhat. That just does not make them the best technology in many cases, but better fibers, the use of composites, etc can easily make them much, much better than basic doped paper drivers.

I agree, and Polk Audio agrees. That is why the SDA drivers are not "basic" doped paper drivers. This is from a 1987 SDA series brochure:

"Exclusive Trilaminate-Polymer Drivers - Polk drivers are unique and superior in performance and reliability. Rather than accepting the sonic compromises of one cone material, we laminate three complimentary cone materials together to achieve a level of performance unmatched by simple paper or plastic cones. The basic lightweight and strong fiber cone is first laminated with a space-age polymer that stiffens the material to prevent distortion; a second polymer is then added to eliminate resonance and coloration through visco-elastic damping."

This is from a 1991 SDA SRS TL series brochure:

"Each SRS model features an array of Polk's exclusive Trilaminate Polymer 6 1/2" midbass drivers that exemplify today's state-of-the-art loudspeaker technology. By combining three complementary materials, each with a specific beneficial property, a performance level is attained that is beyond the reach of conventional drivers that use simple paper or vacuum-formed plastic cones."

Mr. Bubbles wrote: »

Now to your final point; Polk only addreessed the "Progressive Point source Technology" in the tweeter array. Though i believe this to be a vast improvement over what it may have sounded like in a system not utilyizing this technology, it still does not provide the source point accuracy of a single driver.

It does when used in conjunction with SDA's "Line Source Array" technology. Even more than point source accuracy, SDAs offer point source stability, meaning, when properly set up with proper positioning and appropriate low-noise, high-current amplification, the image does not collapse or wander with small movements in head position.

Mr. Bubbles

DarqueKnight wrote: »

It does when used in conjunction with SDA's "Line Source Array" technology. Even more than point source accuracy, SDAs offer point source stability, meaning, when properly set up with proper positioning and appropriate low-noise, high-current amplification, the image does not collapse or wander with small movements in head position.

I will simply agree to disagree with you on this point. Until I can see some plots of the distortion and phase relationships of the multiple drivers compared to a simlar (nearly) single driver copliment. (possibly the 2B or CRS+) I will not believe the distortion (due to the phase relationships between multiple drivers) is lower in a multiple driver setup even with the progressive point source technology. Image position on the soundastage may be an entirely different matter however.

mopar paul

Toolfan66 wrote: »

But ( I was engineer for boeing 15 years )

Haha!!

And he worked on three planes that were built over 20 years apart lol.

nooshinjohn

mopar paul wrote: »

And he worked on three planes that were built over 20 years apart lol.

The closest he got to being involved with projects of that significance, given his profound lack of understanding how to type would have been at the up-right end of a broom handle sweeping the shop floor.

DarqueKnight

Mr. Bubbles wrote: »

Until I can see some plots of the distortion and phase relationships of the multiple drivers compared to a simlar (nearly) single driver copliment. (possibly the 2B or CRS+) I will not believe the distortion (due to the phase relationships between multiple drivers) is lower in a multiple driver setup even with the progressive point source technology. Image position on the soundastage may be an entirely different matter however.

Fair enough. If this is of interest to you, contact Ken Swauger and see if he can get some comparative distortion test information from Polk's engineering department.

Inspector 24

Seriously, why all the animosity? Did I miss where this person attacked or offended someone directly? Because he's got some negative, direct personal attacks on him.

scubasteve4sq

His post count is clearly inferior, that's why.
Petty Internet tyrants...

ZLTFUL

Inspector 24

scubasteve4sq wrote: »

His post count is clearly inferior, that's why.
Petty Internet tyrants...

ZLTFUL wrote: »

Kinda what I thought...

Nathan Fillion FTW.

Negativity FTL.

I for one hope he does it and posts back with his results at some point. He's got the 1.2's to compare to, I hope he will be honest with himself and us of the results. Another positive spin on this, at least he's not hacking up a perfectly good set of 1.2's to modify like some have.

Also, a little inspiration for the OP:
http://www.polkaudio.com/forums/showthread.php?53273-Started-my-new-custom-SDA-s-today

PolkMaster1

Can someone provide a status update with this project?

I am looking for the following information:

Amount of time wasted

Money spent on this project that could have been used on that home improvement project they never got to

The sonic results of the project, and how it compares to their 1.2TLs that they have

If the materials purchased for this project has been burned down or buried in their own back yard

If this person is still working at boeing making paper planes - this is very important !!!

And if google translate could be used to decypher what the original OP was trying to say.

From what I gather, English is not their original language - we would have been better off using google translate in their original language.

I figure the time I took on reading this, and the difficulty of trying to read the original post, and all their posts that follow, which I could not get through - I should be entitled to find out what the end results are of this dead-end project.

K_M

This was from 2.5 years ago.................

PolkMaster1

I know. I was looking into cabinet building for woofers and subwoofers. I somehow came across a link in a forum that bought me here. I think it was AE Speakers or AVS forum.

I am curious to see what the responses are.