the next sda srs 1.2 tl

scubasteve4sq

Also fyi what you are attempting has already been tried

http://www.parts-express.com/project-gallery-speaker-project-stereolithic

Toolfan66

Your idea of a passive is still the worst part of your project, and will not work...

Dennis Gardner

Damn these trainwrecks!!!! I wanted to leave at rino liner, but can't help myself.

westmassguy

Dennis, doesn't everyone use rhino liner when upgrading their Polks?

voltz

I think if you bought some crossover software and enter into it all your calculations it would probably give you the answer you NOT looking for, which is "DON'T DO IT"

I think if Douglass Adam's was still alive he could give you a better answer then me.

Dennis Gardner

The OP must be related to this guy. 9 foot tall speakers with Persian rugs on hardwood floors, with no finished ceiling. But damn don't those speakers look nice......

DarqueKnight

Mr. Bubbles wrote: »

Doped paper is a fine material and was excellent for the day. However technology has come long ways since then with lighter stiffer materials. Doped paper is sufficiently stiff when the driver is moving forward but can have a tendancy to flex when the driver is compressing the air inside the cabinet with the cone moving backwards. This causes distrtion and loss of low end output, especially when coupled with the large passives used in the Polks. The cone flex under compression reduces the potential output from the passive. Used only as a mid; doped paper has few problems. This is not the case in these old Polks.

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."

Mr. Bubbles wrote: »

However, without doing any research, I know that Morel is one brand that could come close to these specs with better technology and stiffer cone materials.

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.

Mr. Bubbles wrote: »

Without going into great detail... the more points of origin a sound comes from the more points in space the brain locates for that sound. these points are normally not at an exact same distance or angle and therefore will incurr time/phase problems for the brain to pinpoint the exact location the sound "should have" come from. This clutters the sound.

The same basic principle as delaying the speaker channels in a surround sound system. With a non-SDA speaker such as the monitor 10 this can be controlled somewhat with speaker toe and placement. With line arrays as the OP eludes to it can be controlled to some extent with the angle of the baffle, but this then effects the on/off axis properties. With the SDA's that is not an option.

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."

DarqueKnight

CLUBCARRERA wrote: »

this is what i am building i named them sound force 1.2S need help modifying the 1.2tl crossover design for two more tweeters the big woofer is a 18" that i removed the magnet and voice coil to make it a passive radiator

What size room would these be placed in?

BKphoto

HA....This has been an entertaining read...

Thanks...

nooshinjohn

Looking at the name he put on his crossover boards... I wonder how Polk feels about their brand name being associated with this debacle???

Perhaps a cease and desist is in order.

CLUBCARRERA wrote: »

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DarqueKnight

F1nut wrote: »

If you want to hear a done right, none SDA speaker check out one of the upper end Sonus Fabers.

But look at the cost!

:sad:

These are the retail prices of Sonus Faber speakers comparable in size and output to the SDA series

Aida - $120,000
Lilium - $65,000
Stradivari - $45,000
Amati Futura - $36,000
Guarneri (Bookshelf) - $22,000.

Caveat: Please be advised that all of the Sonus Faber models listed above use doped paper drivers.

PolkieMan

I agree, do that then you will have a baseline for comparison. You may find you are where you need to be already.

TennMan wrote: »

I think this project should stay inside Photoshop until all the bugs are worked out, which is going to take a long, long time. That way it will be much easier to make changes to your design and you can add as many drivers as you want. When you want to try it out to see how it sounds, all you have to do is play your favorite CD thru your computer speakers. For computer speakers I recommend a pair of Polk 1.2TLs that have been upgraded with the best components you can get.

F1nut

DarqueKnight wrote: »

But look at the cost!

:sad:

These are the retail prices of Sonus Faber speakers comparable in size and output to the SDA series

Aida - $120,000
Lilium - $65,000
Stradivari - $45,000
Amati Futura - $36,000
Guarneri (Bookshelf) - $22,000.

I stated years ago when I was considering replacing my SDA's that it took the Amati Anniversario at $30k to come close to the SDA sound, but they still lacked the sound stage.

Caveat: Please be advised that all of the Sonus Faber models listed above use doped paper drivers.

Imagine that.

F1nut

nooshinjohn wrote: »

Perhaps a cease and desist is in order.

Forthcoming, I'm sure.

squeeb

"Failure provides the opportunity to begin again, more intelligently." ~ Henry Ford

Sounds like you have the money, the time, the patience ... Others on here have been around these speakers for many, many years. If you want to blaze you own trail - go for it.

voltz

think DK's tag line says it perfectly

"Knowledge, without understanding, is a path to failure."~DK

I remember earning one of Jesse's patented "FAILED" in the past!

CLUBCARRERA

on the subject of coating the inside of the speaker boxes with a rubberized coating like rino liner to help deaden sound waves is a fact! case in point I was engineer for boeing 15 years I worked on the b1 ,b2 and the yf22 projects we did test for radar and sound waves deadening in seattle across from the boeing air museum are test wing models where made of wood and coated with a rubberized coating we found that 1/2" peace of wood with a 1/16" coating would be the same as a 4'' to 5'' peace of wood on sound deadness all of are stealth aircraft use a special type of rubberised coating for that reason we did a test on a side by side subwoofer box one with HushMat® ACOUSTIC SOUND DEADENING MATERIAL and one with out hands down the coated box sounded best by far the big reason why speaker manufacturers do not use it is costs and added wight also aheastion the wood needs to be epoxy coated for the rubberizing to stick all new cars use it,

CLUBCARRERA

got the information from parts express on the needed tweeter crossover points so my first test will be to set up a temp line array with my 6 sl3000 tweeters with the new cross over points my neighbor has nice set up of polk 1.2 bi amped so we will do testing on my 6 tweeter setup and the stock 4 tweeters set up in the 1.2 side by side also going to see or hear if spreading the tweeters apart will make a improvement in presents and sound stage will let you know

westmassguy

CLUBCARRERA wrote: »

on the subject of coating the inside of the speaker boxes with a rubberized coating like rino liner to help deaden sound waves is a fact! case in point I was engineer for boeing 15 years I worked on the b1 ,b2 and the yf22 projects we did test for radar and sound waves deadening in seattle across from the boeing air museum are test wing models where made of wood and coated with a rubberized coating we found that 1/2" peace of wood with a 1/16" coating would be the same as a 4'' to 5'' peace of wood on sound deadness all of are stealth aircraft use a special type of rubberised coating for that reason we did a test on a side by side subwoofer box one with HushMat® ACOUSTIC SOUND DEADENING MATERIAL and one with out hands down the coated box sounded best by far the big reason why speaker manufacturers do not use it is costs and added wight also aheastion the wood needs to be epoxy coated for the rubberizing to stick all new cars use it,

All that may be true, however lining the interior of the SDAs with sound deadening or absorbing material has been tried by other members. It detracted from the SQ. That's why BH5 is recommended only in strips, directly behind the woofers, and nowhere else.

CLUBCARRERA

the math tells me that the added 4 speakers to the cabinet calls for the 18" pr so in telling me it will not work is tell me nothing should I do two 12" pr one firing rear one faring front go to a port instead if you look at the polk speaker line up you will see the more drivers polk adds the bigger the cabinet and the bigger the passive radiator more speakers move more air gust got a new idea if you can make a flat round speaker box put a small driver in the middle then do a snail pattern transmission line the nice thing about that unlike stander speaker box transmission line types you would not have all the irregular port sizing may try that next ?

Toolfan66

westmassguy wrote: »

All that may be true, however lining the interior of the SDAs with sound deadening or absorbing material has been tried by other members. It detracted from the SQ. That's why BH5 is recommended only in strips, directly behind the woofers, and nowhere else.

I am one of those guys!! Big fail...

Toolfan66

CLUBCARRERA wrote: »

the math tells me that the added 4 speakers to the cabinet calls for the 18" pr so in telling me it will not work is tell me nothing should I do two 12" pr one firing rear one faring front go to a port instead if you look at the polk speaker line up you will see the more drivers polk adds the bigger the cabinet and the bigger the passive radiator more speakers move more air gust got a new idea if you can make a flat round speaker box put a small driver in the middle then do a snail pattern transmission line the nice thing about that unlike stander speaker box transmission line types you would not have all the irregular port sizing may try that next ?

It's not the 18"size, it's the way you want to build one, that is the fail.. Now if you could actually find an 18" PR that is toned for the project, then by all means knock yourself out, even though I still think it won't work..

I have tried a few things and failed, but I still had fun trying it, but in your case the passive idea kills the project right out the gate..

Not sure about using two passives, Polk has a couple of speakers with two passives but they are not SDA's..

nspindel

CLUBCARRERA wrote: »

the math tells me that the added 4 speakers to the cabinet calls for the 18" pr so in telling me it will not work is tell me nothing should I do two 12" pr one firing rear one faring front go to a port instead if you look at the polk speaker line up you will see the more drivers polk adds the bigger the cabinet and the bigger the passive radiator more speakers move more air gust got a new idea if you can make a flat round speaker box put a small driver in the middle then do a snail pattern transmission line the nice thing about that unlike stander speaker box transmission line types you would not have all the irregular port sizing may try that next ?

You should try some punctuation at some point. Maybe that would help people understand what the heck you are even talking about.

westmassguy

CLUBCARRERA wrote: »

the math tells me that the added 4 speakers to the cabinet calls for the 18" pr so in telling me it will not work is tell me nothing should I do two 12" pr one firing rear one faring front go to a port instead if you look at the polk speaker line up you will see the more drivers polk adds the bigger the cabinet and the bigger the passive radiator more speakers move more air gust got a new idea if you can make a flat round speaker box put a small driver in the middle then do a snail pattern transmission line the nice thing about that unlike stander speaker box transmission line types you would not have all the irregular port sizing may try that next ?

You can't mix Passive radiators and Ports, it's one or the other. 18" PRs can be had, some are relatively inexpensive, however tuning them properly is another matter. Doing multiple front and back passives has been done, the RTA15TL for example, but that can result in phase issues, which can hinder bass performance. I'd still like to know how you're going to add two additional woofers to the four stereo and dimensional harnesses, and end up with a 4ohm and 8 ohm nominal load the crossover requires.

halo71

This thread was a hard read! I had a hell of a time trying to decipher the OP's posts.

voltz

It all went over my head.... maybe that is why I'm bald on top?

Toolfan66

nspindel wrote: »

You should try some punctuation at some point. Maybe that would help people understand what the heck you are even talking about.

But ( I was engineer for boeing 15 years )

Haha!!

DarqueKnight

CLUBCARRERA wrote: »

the math tells me that the added 4 speakers to the cabinet calls for the 18" pr so in telling me it will not work is tell me nothing should I do two 12" pr one firing rear one faring front go to a port instead if you look at the polk speaker line up you will see the more drivers polk adds the bigger the cabinet and the bigger the passive radiator more speakers move more air gust got a new idea if you can make a flat round speaker box put a small driver in the middle then do a snail pattern transmission line the nice thing about that unlike stander speaker box transmission line types you would not have all the irregular port sizing may try that next ?

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.

halo71

DK, come on now. If one can knock the magnet off a woofer and viola...instant passive radiator. The rest can't be that hard! lol

Toolfan66

halo71 wrote: »

dk, come on now. If one can knock the magnet off a woofer and viola...instant passive radiator. The rest can't be that hard! Lol

lol!!!