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NotThisChris

Altec 511b inside of a Cornwall.

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Posted (edited)

Thought you guys might enjoy my latest accident.  I have never attempted anything like this but have help from some knowledgeable people. Drivers will most likely be a B&C DE250 and an MCM 55-2953 (until I find something better, they came with this.) 

 

These guys were pretty mangled cabinets filled with probably the cheapest drivers one could buy and fit in a Cornwall cab. I know people put them on the top, but oh well.  

 

D02138D3-F243-4A01-8F09-AAA730C66D6A.thumb.jpeg.c7236e957d2bb11dee7101599288924f.jpeg065ED01C-28F7-4F35-9857-905945C1A9A8.thumb.jpeg.ad50ffb8b3b54bd08744c4e6a9245d8e.jpeg

Edited by NotThisChris
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2 minutes ago, hanksjim1 said:

you might want to check out the Altec Valencia for some ideas....

The Valencia uses and 811 horn, which is an 800 Hz. horn. The 511 is a 500 Hz. horn. I used to own 4 of those in the 70's. You may want to consider and Altec 902 driver, which is designed for that horn..................if it will fit.

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4 minutes ago, ClaudeJ1 said:

The Valencia uses and 811 horn, which is an 800 Hz. horn. The 511 is a 500 Hz. horn. I used to own 4 of those in the 70's. You may want to consider and Altec 902 driver, which is designed for that horn..................if it will fit.

http://greatplainsaudio.com/wp-content/uploads/2016/06/902series-1.pdf

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1 hour ago, ClaudeJ1 said:

The Valencia uses and 811 horn, which is an 800 Hz. horn. The 511 is a 500 Hz. horn. I used to own 4 of those in the 70's. You may want to consider and Altec 902 driver, which is designed for that horn..................if it will fit.

the Altec 511B is 18,5 inches long at the adapter plate ,  The CW1 is 15,5 inches  deep , the  511B horn-500hz   is extending out of the cab in the rear  , and the cabinet 's internal volume is also lower -  a K400 at 400hz would have taken up less  volume  as well as being a better horn

 

http://alteclansingunofficial.nlenet.net/proloudspeakers/sectoralhorns/511B&811B-Data.pdf

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2 hours ago, NotThisChris said:

Thought you guys might enjoy my latest accident.  I have never attempted anything like this but have help from some knowledgeable people. Drivers will most likely be a B&C DE250 and an MCM 55-2953 (until I find something better, they came with this.) 

 

These guys were pretty mangled cabinets filled with probably the cheapest drivers one could buy and fit in a Cornwall cab. I know people put them on the top, but oh well.  

 

D02138D3-F243-4A01-8F09-AAA730C66D6A.thumb.jpeg.c7236e957d2bb11dee7101599288924f.jpeg065ED01C-28F7-4F35-9857-905945C1A9A8.thumb.jpeg.ad50ffb8b3b54bd08744c4e6a9245d8e.jpeg

can you post pictures from the rear of the speaker , and the interior --------tx

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Apologies, I don’t get emails, need to set notifications for replies. Here are the photos of the rear. An active crossover is certainly in the cards, Probably needed since I’ve changed the dynamics of how the cabinet sounds. 

 

Randyh, you are correct. This is part of the reason I haven’t picked up Altec drivers for these. I needed something low profile, so I don’t have a big lump sticking out of the back. The horn does fit.... without a compression driver attached. 🙃
 

This isn’t really a build of what I want, more like this is what I have and can I make it work. I would have preferred a K400 but the purchase came with the 511b horns, a mangled pair of  808-8A drivers, a Pyle mid horn and pds152 driver, MCM 55-2953 woofer, and crites CT-125 tweeter. They are far from done.F1E5B17C-CE5D-476F-B177-3036F241A6B5.thumb.jpeg.968f1f2036ea4e84226170c921db54c6.jpeg03DB0BD1-DB86-4A0A-B6E8-75618A9DDC8E.thumb.jpeg.baff44f9a9cb9e744e71895a9a76f824.jpeg

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2 hours ago, RANDYH said:

the Altec 511B is 18,5 inches long at the adapter plate ,  The CW1 is 15,5 inches  deep , the  511B horn-500hz   is extending out of the cab in the rear  , and the cabinet 's internal volume is also lower -  a K400 at 400hz would have taken up less  volume  as well as being a better horn

 

http://alteclansingunofficial.nlenet.net/proloudspeakers/sectoralhorns/511B&811B-Data.pdf

It doesn't state which point from which the Depth dimension is measured. Is it the peak of the front radius or from the rear of the flat mounting flange?? If you assertion is correct, then why does it even FIT into a Cornwall to begin with?

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23 minutes ago, NotThisChris said:

Randyh, you are correct. This is part of the reason I haven’t picked up Altec drivers for these. I needed something low profile, so I don’t have a big lump sticking out of the back. The horn does fit.... without a compression driver attached. 🙃

Just build a rear extension out of 3/4" plywood, thereby increasing the box volume slightly to accommodate the right driver. A 902 is a very good driver, but there are other flat ones, just no many that get to 500 Hz. so you could get a K55 with adapter and make it fit with the rear cab extension that would fit into the existing opening. 

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22 minutes ago, ClaudeJ1 said:

Just build a rear extension out of 3/4" plywood, thereby increasing the box volume slightly to accommodate the right driver. A 902 is a very good driver, but there are other flat ones, just no many that get to 500 Hz. so you could get a K55 with adapter and make it fit with the rear cab extension that would fit into the existing opening. 

All of those are great ideas. The extension is the next thing on my list, err our list. This is as much their project as it is mine. I merely cut a hole and installed them. 

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1 hour ago, ClaudeJ1 said:

It doesn't state which point from which the Depth dimension is measured. Is it the peak of the front radius or from the rear of the flat mounting flange?? If you assertion is correct, then why does it even FIT into a Cornwall to begin with?

you-re right , it fits , he posted pictures ---------but here's the specs sheet http://lampizator.eu/SPEAKERS/PROJECTS/P23/811B%20HF%20Horn.pdf

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1 hour ago, NotThisChris said:

Apologies, I don’t get emails, need to set notifications for replies. Here are the photos of the rear. An active crossover is certainly in the cards, Probably needed since I’ve changed the dynamics of how the cabinet sounds. 

 

Randyh, you are correct. This is part of the reason I haven’t picked up Altec drivers for these. I needed something low profile, so I don’t have a big lump sticking out of the back. The horn does fit.... without a compression driver attached. 🙃
 

This isn’t really a build of what I want, more like this is what I have and can I make it work. I would have preferred a K400 but the purchase came with the 511b horns, a mangled pair of  808-8A drivers, a Pyle mid horn and pds152 driver, MCM 55-2953 woofer, and crites CT-125 tweeter. They are far from done.

looks good to me  , it fits -----

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Posted (edited)
18 minutes ago, soundbound said:

Welcome. Nice job. What speakers and crossovers were in them?

Thank you for the greeting. IIRC, they started out as a set of Cornwalls with unbranded tweeters, Pyle PDS182 mids with 5 cent plastic midhorns, an MCM 55-2953 15” woofer, and emb CX-10 crossover.   The cabinets were the most expensive thing but were also pretty badly damaged. 
 

I received them with a pair of crites CT125s in place of poo tweeters, and a pair of altec 511b horns with 808-8A drivers, those properly knackered with too. 
 

currently, I’m running them with B&C DE250s, The woofer listed above and a homemade crossover, 18db HPF and 6db LPF both set at 900hz and an L-Pad on the Horn because it over-powers the woofer many times over. 

5E131659-1CCC-4425-8FD0-D808E96E31D9.jpeg

D94C5505-5A2C-4782-A9CC-FBF49033E718.jpeg

Edited by NotThisChris

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Good toys to play with.  Will take some time to sweeten them up.

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The project is done, sort of.  I’m having issues with balance due to the Lpads I purchased not being matched. I need to see if I can take it apart to make it work. 

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E38100DA-C7AD-4C79-BF36-B4CB85754B7B.thumb.jpeg.f645f226a6f40d312c5b63c6f45f7f97.jpegFEC980E5-07CC-40E3-BEC8-21EC83BEF71E.thumb.jpeg.2d1fb4582cebdafc788334b918b2e483.jpeg

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a fifteen inch woofer with a 900Hz. xover point and a 6db/octave roll off? not much of a plan. you could slap an acoustic filter over the woofer that wold help a little. time for an active xover and a couple of inexpensive stereo block amplifiers.

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19 minutes ago, moray james said:

a fifteen inch woofer with a 900Hz. xover point and a 6db/octave roll off? not much of a plan. you could slap an acoustic filter over the woofer that wold help a little. time for an active xover and a couple of inexpensive stereo block amplifiers.

To some extent I agree. An active crossover was always the plan but I know nothing of where or how to implement. Other than the Lpad being wonky, they sound quite good to me, but to each their own. 
 

Why do you think the crossover is inadequate? Would an active crossover be ok considering I run only tube amplifiers on my speakers? 

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crossover point is not the issue the slope is the issue (not saying it is the best point but it's not a bad choice for your driver). Trouble is that at 1800 Hz. your woofer output is only 6 db down in level from the xover point of 900Hz., at 3600Hz it is only 12 db down do you think you really want o be listening to this? along with the scattered dispersion from such a large woofer with waves that cancel and those which couple you are going to have a loudspeaker which will not disappear. Using an active xover will let you easily find the best crossover point and slope as well as the   crossover filter type, you will need four channels of amplification and it does not matter if they are SS or tube matching gain of all the channels is a good idea which is why I suggested two stereo block amps same brand/model will work well. You should be able to come up with a nice two way, I like two ways have fun. I hope this helps.

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