Started my new custom SDA's today

Systems

Isn't DIY fun.
After that much work you deserve a rest.

heiney9

Get back to work!!!:mad:

H9

engtaz

Too funny slave drivers? LOL

Mazeroth

Which brand/model of drivers are you using. I'm a seasoned speaker builder myself and thought about buliding a pair of cheaper SDAs for kicks. With over 500 drivers in my basement it wouldn't be a problem

ben62670

Mazeroth wrote: »

Which brand/model of drivers are you using. I'm a seasoned speaker builder myself and thought about buliding a pair of cheaper SDAs for kicks. With over 500 drivers in my basement it wouldn't be a problem

I am using all Polk MW woofers, and Morel tweeters. Polk still have the MW's, and with an fz of 29-31 they are the best, clearest, most efficient speakers around. I looked for something cheaper, and better. No dice. It is definitely worth building them. Have you ever heard SDA's before?
Ben

ben62670

Well I am working on my SDA control box seeing my back still hurts from yesterday, and last night. It has 3 inputs, and six outs. 2 outs are going to be SDA/subs, 2 will be stereo, and 2 will be the highs. The center nob is a fader for bias between the Dim's, and the Stereo's. I will finish installing the level control for the highs later.

Mazeroth

ben62670 wrote: »

I am using all Polk MW woofers, and Morel tweeters. Polk still have the MW's, and with an fz of 29-31 they are the best, clearest, most efficient speakers around. I looked for something cheaper, and better. No dice. It is definitely worth building them. Have you ever heard SDA's before?
Ben

Fs doesn't attribute to the clarity or efficiency of the speaker, just the resonant frequency of the driver. The higher the moving mass of the driver, the lower the Fs. When moving mass goes up, efficiency drops. Anywho. Did you test any other drivers out before picking the MW? Also, what was the damage on those guys and which Morel did you end up going with?

I had a chance to listen to a few SDAs in my days. Very nice sounding speakers with crazy imaging. I built a pair of line arrays two years ago and just recently got rid of them, making room for my next pair of line arrays. Here's a thread of my build:

http://www.polkaudio.com/forums/showthread.php?t=27913

I'm currently listening to a pair of 3-way dipole speakers I'm building that sound too good to be true. Check them out here:

http://www.htguide.com/forum/showthread.php4?t=24590

Keep us posted with your progress! Good work so far!

ben62670

Wow. Very nice looking line arrays. I tried some EOS one drivers, and a couple of the cheaper dayton paper cones. I drove them electronically crossed over with a tweet. I liked the Polk's the most for vocals, and bass slam. The Morels I chose are the MDT20's. I am doing passive inline crossovers before the amp, and I was thinking about doing a L/R 12db to keep the phase correct on the tweets for 24db total. I do not know for sure how I am going to wire the tweets yet. I think there will be some trial, and error involved with those;)

Keep up the good work!
Ben

ben62670

Well today I am starting the speaker wiring harnesses. I have over 80 fast on connectors to crimp:(

hearingimpared

ben62670 wrote: »

Well today I am starting the speaker wiring harnesses. I have over 80 fast on connectors to crimp:(

When you wake up tomorrow your hands are going to look like claws!

jcaut

Man, you've gotta be pretty dedicated to take on this project. I like building speakers, but I hate building cabinets.

I didn't read through all 5 pages so I apologize if you've already been asked this. How are you deriving the SDA signal?

Jason

ben62670

jcaut wrote: »

Man, you've gotta be pretty dedicated to take on this project. I like building speakers, but I hate building cabinets.

I didn't read through all 5 pages so I apologize if you've already been asked this. How are you deriving the SDA signal?

Jason

I was thinking of trying it 2 ways, and see what is best. The first way. Seeing that the dims are on their own circuit with no caps, or inductors for the crossover I was thinking about running the hot straight out of the amp into the positive of they dim array. From inside of the cabinet running the negative out of the cabinet to the negative in the other cabinet. So both hots are connected to the amp. Both grounds are connected to each other. OK now I don't have the ground connected to the amp. In the center of the speaker cable (read single custom speaker cable) ground I was thinking of attaching an 8mh inductor(1.2TL's use 16mh per cab. Inductors are like resistors value drops in half when Parallel). One side of the inductor is connected speaker cable ground, and the other side of the inductor is connected to both sides of the amp ground. Circuit complete.:) Second way Blade blade caps, and inductors like SDA-SRS. :cool:

hearingimpared

ben62670 wrote: »

I was thinking of trying it 2 ways, and see what is best. The first way. Seeing that the dims are on their own circuit with no caps, or inductors for the crossover I was thinking about running the hot straight out of the amp into the positive of they dim array. From inside of the cabinet running the negative out of the cabinet to the negative in the other cabinet. So both hots are connected to the amp. Both grounds are connected to each other. OK now I don't have the ground connected to the amp. In the center of the speaker cable (read single custom speaker cable) ground I was thinking of attaching an 8mh inductor(1.2TL's use 16mh per cab. Inductors are like resistors value drops in half when Parallel). One side of the inductor is connected speaker cable ground, and the other side of the inductor is connected to both sides of the amp ground. Circuit complete.:) Second way Blade blade caps, and inductors like SDA-SRS. :cool:

Who's on first;

What's on second;

I dunno's on third!!!:D

heiney9

Ben I applaud your effort and thinking, but you seem to have taken a fairly complex idea (Stereo Dimensional Array) and simplified it. I can’t imagine it working at all like Polk originally executed it. They had all sorts of phase correction, signal correction and compensation built into the x-overs. Even the cascaded taper array of the tweets was a complicated effort to keep refraction, lobing and off axis response acceptable. How are you compensating for phase issues and lobing issues and on/off axis response, etc. How are you going to make sure the multiple tweets play smoothly and are a true point source? Frequency response is but one small part of making a speaker an enjoyable top performing experience.

Please take this as constructive criticism and not as a knock on your project.

H9

ben62670

Well I have been thinking about the home theater thing, and the glare issues with the speakers next to the screen. I think I am going to go the original SDA route with the wood trim, and the grill cloth on the sides.;) :cool:

ben62670

heiney9 wrote: »

Ben I applaud your effort and thinking, but you seem to have taken a fairly complex idea (Stereo Dimensional Array) and simplified it. I can’t imagine it working at all like Polk originally executed it. They had all sorts of phase correction, signal correction and compensation built into the x-overs. Even the cascaded taper array of the tweets was a complicated effort to keep refraction, lobing and off axis response acceptable. How are you compensating for phase issues and lobing issues and on/off axis response, etc. How are you going to make sure the multiple tweets play smoothly and are a true point source? Frequency response is but one small part of making a speaker an enjoyable top performing experience.

Please take this as constructive criticism and not as a knock on your project.

H9

I hear you on that, and have done a lot of studying of line arrays, and phase issues. I think you missed an earlier post where I am going to send the high frequencies from the amps to the cabs. I will actually be adding a crossover section within the cabs for the tweets to
A: increase the slope to 24db
B: correct phase problems with higher frequencies.
I have studied many Polk SDA XO's, and will be cutting the higher frequencies to the outer, or upper tweets. This will take time to get right. I would love it to just work the first time, but I do fully understand the complex issues with the tweeter arrangement. The XO will be mounted outside the cabinet till I get it right!

Thanks H9;)

ben62670

Well I am finally posting a pic of the wiring harnesses for the MWs. 72 crimp ons total.

ben62670

The last of my drivers will be here tomorrow! I should be up and running this weekend. I finally stopped wasting time on ebay, and went straight through Polk.

ben62670

Drivers, drivers, and more drivers.:D

jakelm

LOL...Open you own Polk parts store Ben.

I'll take 2 mw6500's and 2 mw6510's...lol

The CS at the Polk store must have wonderd what the hell you needed all those drivers for...lol

Very nice speakers.

Poor sonotube. What did you do to it???:mad: :mad: I'm crying..:(

ben62670

jakelm wrote: »

LOL...Open you own Polk parts store Ben.

I'll take 2 mw6500's and 2 mw6510's...lol

The CS at the Polk store must have wonderd what the hell you needed all those drivers for...lol

Very nice speakers.

Poor sonotube. What did you do to it???:mad: :mad: I'm crying..:(

I neutered it.:D

I feel like less of a man with it like that.:o Now if I started with a 5 footer it would be cool. I hated to shrink it.:(

engtaz

ben62670 wrote: »

I neutered it.:D

I feel like less of a man with it like that.:o Now if I started with a 5 footer it would be cool. I hated to shrink it.:(

Hey you said you were not going to take pictures of the sub. LOL

jakelm

ben62670 wrote: »

I neutered it.:D

I feel like less of a man with it like that.:o Now if I started with a 5 footer it would be cool. I hated to shrink it.:(

Made a mountain into a mole hill.

You said it was 4' tall with a 15" Dayton in it? It still must sound very good. But is that enough airspace for the 15"?

ben62670

engtaz wrote: »

Hey you said you were not going to take pictures of the sub. LOL

I lied:p

engtaz

You having too much fun. Well well How do they sound. I know you waiting to break them in but what are the intial thoughts.

ben62670

jakelm wrote: »

Made a mountain into a mole hill.

You said it was 4' tall with a 15" Dayton in it? It still must sound very good. But is that enough airspace for the 15"?

With the end caps it is almost 5 feet. I have a hard time saying its less that 5 feet tall:o

I just counted up all my mw's not in use, and I have 43. 32 for this, 8 for SDA1 C's, and only 3 left. I need more drivers for my center. I was thinking an 8 MW center, but how much do I really need. 4 MW's is plenty to keep up with any movie listening, and really don't think these are going to be much louder than the towers I have now. My first experiment used 4 MW's, and 2 10" PR's and they hit 120db. They were louder than the SRS copies I have now by 2 or 3db, but did not have the full open sound stage that I have now. I am very excited to get these together this week. Maybe a test drive this Sunday?

jakelm

Where are the finished pics??

agfrost

Much respect to you, Ben. I couldn't dream up such a project, let alone bring it to reality.

Hope they sound as impressive as they look!

Jay

ben62670

jakelm wrote: »

Where are the finished pics??

I'm not done yet. I just got the drivers today. I ran out of money to "finish" the cabs, but they will be operational soon. I'll post pics and thought after I fire them up. Take a quick peak at this. Page three is what I am all about.

http://www.audiodiycentral.com/resource/pdf/nflawp.pdf

ben62670

agfrost wrote: »

Much respect to you, Ben. I couldn't dream up such a project, let alone bring it to reality.

Hope they sound as impressive as they look!

Jay

Thanks Jay. I definitely appreciate it. I have spent a lot of time researching this project. The research has take so much more time than the actual work!