La Scala's with 511b's!

[RandG]

I have been reading and learning from all of your posts for nearly a year now and I just have to share with you guys my happiness with the Altec 511b horn.
I just recently added a pair to my system and I am just floored with the improvement in sound quality that they are producing. I liked my La Scala’s before, but I think I love them now! I do realize that they are not true Klipsch products anymore, but man they have never sounded better to me then they do now with these horns.

My system consisted of a pair of 1976 industrial La Scala’s with K55v drivers (push pins), Bob’s tweet’s, woofers and replacement Sonicaps for the crossovers. So I guess the cabinet/bass bin, AA crossover fragments and the K55v are all that remains of the original Klipsch product, but I do believe that the sprit is still there! My boys are powered by a pair of mono Eico HF50’s rebuilt and modified to accept push and pull 6550 Tung-Sol’s by Gary Dodd. Lower bass support is being enhanced by a Velodyne HGS 10 1000w subwoofer.

I am sampling Santana’ first album now and the sound that these 511b’s are projecting of the Congo’s are just simply outstanding and Carlos’s guitar has never sounded more alive! Earlier today I had listened to some T-bone Walker and a little Traffic and oh my god, I don’t know if you can relate to my music, but Traffic’s “John Barleycorn Must Die” album with these horns just leave me in awe of the musicians who created this album and also of the ability of these 511b’s to reproduce it!

I think I have almost make it to heaven, sonically speaking, but heaven does seem to be lacking a little natural bass at lower levels and some clarity in the mid’s at higher levels. The quest seems to be never ending; I am now trying to figure out why I got into this in the first place (if only I could have been satisfied with the JVC). I guess the next step may be to add a pair of Altec 902’s and an active crossover giving me the ability to add my Carver SS Amps to the lower end. After this mod the cabinet/bass bin will be last remaining component of my original La Scala’s, I hope I will still be welcomed here.

Any other suggestions would be welcomed and greatly appreciated!

[Guest " "]

LaScala's are the subject of much of the forum modification threads.

I just got done doing a limited upgrade to a pair of LaScala Professionals. These are the sealed back , one piece, metal trim models.

The Professionals initially had AA xovers, K-55-V's, k-33's, K-77-Alinco, and the original 14 gaure corrosion prone wire with solder tin'd spade connectors.

After cutting out the top of the dog house to connect the woofer chamber to the xover chmber, I installed AL-3 xovers, k-43-kp (cast frame) woofers, k-55-m mid drivers, a modified pair of k-77-M tweets (magnet and pole assembly from ST-350), thick gauge monster wire with gold plated connectors. Since these will be played at high volume levels, the K-55-M's and the K-77-M's had ferro fluid addred to them.

For my purposes, these now sound ideal....significantly reduced distortion over the previous AA based config, the mid bass area has greater detail due to the larger internal volume ( I'm not going to port them, but will be adding a PA grade sub woofer), the top end has more detail (in spite of the fero fluid).

[Marvel]

I wish you would try the porting. Easily reversable and you're already mostly there.

It would be interesting to hear your take on the porting. Dennis says the K-43 works better (if I remember correctly) Might try 5-7" ports. You will retain the snap compared to the 10" ports.

Bruce

[Guest " "]

I wish you would try the porting. Easily reversable and you're already mostly there.

It would be interesting to hear your take on the porting. Dennis says the K-43 works better (if I remember correctly) Might try 5-7" ports. You will retain the snap compared to the 10" ports. 

Bruce 

I have a second set of backs so I'll give a whirl.

In the past, when ever I used port speakers at large gatherings....they tend to accumulate ice cream cones, candy, forks, spoons, combs, keys, etc. Kids like to hid things inside large speaker cabs......they just can't resist the large port opening. I found many surprises over the years as I noticed rattling sounds in some of my outdoor speakers.

[RandG]

After cutting out the top of the dog house to connect the woofer chamber to the xover chmber

I have not heard of this mod before without porting the back as well, how much of the top did you cut out?

My Professionals had the exact same original configuration as yours, but mine had K43's originally

(Unfortunately I blew them out)

Randy

[bluesboy]

Make the change from the K-55s to 902s. You wont regret it.

[Guest " "]

After cutting out the top of the dog house to connect the woofer chamber to the xover chmber

I have not heard of this mod before without porting the back as well, how much of the top did you cut out?

(Unfortunately I blew them out)

Randy

I used a router and followed the inside wall of the dog house.....so the dog house it self...has no top. I used a drill from the woofer side to cut a 1/2 inch starter hole. The from the crossover area...I used a router with a plunge bit (bearing on the end of the bit) to follow the inside wall.

Data pn connecting the lower chamber to the xover area has been posted before....you actually loose some absolute bottom end if you do not also port as well....but I was after more detailed mid bass, which is what I got...I'll be using a sub for the absolute bottom end.

[IB Slammin]

Make the change from the K-55s to 902s. You wont regret it.

Agree [Y]

[Islander]

You could always replace your K400/K-55s & K-77s with a pair of K510/K-69As. That gives a major improvement, especially if you go to bi-amping, but it gets somewhat more expensive.

[RandG]

Thanks guy's for your input. I do believe I will be going with the 902-8 option. The only thing is, I just today got a good deal on a decent electronic crossover (Fender-Sunn PCN-4) so I will be going 3 way with Bob's CT125's. What do you guys think about what the crossover points should be?

I was thinking maybe 500 hz/ 7500hz.

Randy

[Blvdre]

Randy, I'm putting together a similar three-way (511B/902 and APT-200 tweet), but am using a passive crossover. I'm using 500Hz and 7500Hz per Dean's recommendation.

[RandG]

I'm putting together a similar three-way (511B/902 and APT-200 tweet), but am using a passive crossover. I'm using 500Hz and 7500Hz

Cool, it's good to know I'm on the right track and someone else is headed down the same path! I know diehard 902 fans would say to go 2 way and let the 902 handle all the higher frequencies, how big of a mistake am I making going 3 way? I think a tweeter to top off the highs might be nice thing, but what do I know I just an amateur at this.

Randy

[djk]

Sold under various names (Fender-Sunn PCN-4), the TDM 24CX3 is a favorite of mine for the money, and is better than the low priced DBX, Behringer, Rane, etc.

http://www.tdm-design.com/products_crossovers.php

http://www.tdm-design.com/acrobat/crossovermanual.pdf

[Blvdre]

Since you're using an active cross-over, it might be easy enough to try your set-up as a two-way. The complaint I've heard is that the 902 drops a bit at it's upper end. You may be able to EQ that response a bit with your x-over. I'm not the guy to ask since I have zero experience with actives, but I believe they typically come with EQ features. That way you have the option of trying either two or three way to see which you like best.

[cjgeraci]

I'm putting together a similar three-way (511B/902 and APT-200 tweet), but am using a passive crossover. I'm using 500Hz and 7500Hz

Cool, it's good to know I'm on the right track and someone else is headed down the same path! I know diehard 902 fans would say to go 2 way and let the 902 handle all the higher frequencies, how big of a mistake am I making going 3 way? I think a tweeter to top off the highs might be nice thing, but what do I know I just an amateur at this.

Randy

I wouldn't call using a 902 for three-way duty necessarily a "mistake." Personally, I had APT-200s, Beymas, and JBL 2404s in my system that were all rendered unnecessary once I switched to 902s. To each their own and everyone hears differently.

If you are going active, however, I would cross the 902s at 600 hz or even 700 hz on the bottom. Unlike the Khorn, the LaScalas bass bin should be able to reach that high, and even though 902s can take power if you cross them lower, they sound better to my ears - the higher that you cross them on the bottom.

Have fun and experiment.

Carl.

[Blvdre]

Hi Carl, thanks for the comments. I'm going to try both 3 and 2 way configs to see which I prefer. I think the modified type A passive I'll be using can easily be modified to run as a two way (pull the coil from the squawker, I believe). My guess is that I may not like the roll off of the 902 at the high end. I think this is easier to address with an active set-up. I may try to enlist the help of friend who may be able to provide some EQ via my passive. John Albright provided a response plot of the 902, so that could be our starting point.

[RandG]

Sold under various names (Fender-Sunn PCN-4), the TDM 24CX3 is a favorite of mine for the money, and is better than the low priced DBX, Behringer, Rane, etc.

Thanks djk for the links and extra info. I did purchase this crossover, after reading your recommendation of it.

...so I think I have decided to find a pair of 908's or 909's since my CT125's will be handling the higher frequencies. The 902's does seem to be suited more for two-way operation and is more expensive on the open market. I can always upgrade to 902’s being that 908/909 diaphragms can be replaced with a 902's diaphragm.

If anyone on the board has a pair of 902,908 or 909’s that they want to let go of, I would be highly interested. I would buy them new directly form GPA but I just can’t afford that right now and will need to settle for used ones.

Thanks guys for the recommendations on the crossover frequencies, gives me a great starting point to experiment with.

Randy

[Blvdre]

Randy, there's a pair of the 908's up on e-bay right now.

http://cgi.ebay.com/ALTEC-908-8B-DRIVERS-MINT_W0QQitemZ170214568821QQcmdZViewItem

[PrestonTom]

Randy, I will be interested in your journey using a 511 in a two way configuration.

My friendly advice is that before you get the driver, you should first get some advice from Bill at GPA regrading both the driver and the choice of diaphragm. And let him know that this could be a two-way configuration. Obviously, the horn will need some EQ boost to get the higher frequencies and the diaphragm material needs to be appropriate. GPA can help you out.

Good Luck,

-Tom

[cjgeraci]

Randy, I will be interested in your journey using a 511 in a two way configuration.

My friendly advice is that before you get the driver, you should first get some advice from Bill at GPA regrading both the driver and the choice of diaphragm. And let him know that this could be a two-way configuration. Obviously, the horn will need some EQ boost to get the higher frequencies and the diaphragm material needs to be appropriate. GPA can help you out.

Good Luck,

-Tom

When I bought my 902s new from Bill, we had a discussion about the aluminum v. pascalite diaphragms. Taking into consideration that I was going to cross over at 500 hz, Bill told me that I should not be concerned about overloading the aluminum 902s in a home setting. He also said that he could not audibly tell a difference between the two, but since some people claimed that the 902s were sweeter sounding, he advised that I try the 902s first. There are also those who claim that the pascalite dias do not reach as high as the 902s, but I cannot confirm or deny those claims.

Carl.