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Thread: Brociner folded corner horn?

  1. #1
    Senior Member spkrman57's Avatar
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    Brociner folded corner horn?

    I was reading the post on the forum here and ran across Beowulf57's thread on these horns and I have a similiar pair to his.

    My pair of corner horns are within a inch more-or-less to his and I plan on using either a D131 reconed with 2202H cone, 2225H or a E-130 w/paper dustcap.

    I'm thinking that the 2225H would be the best candidate for the job,

    I welcome and and all comments on this. And yes boys and girls, it will be powered with tubes as is always my favorite.

    I thank Beowulf57 for his thread here:
    http://audioheritage.org/vbulletin/s...ad.php?t=20973

    Regards, Ron
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  2. #2
    Senior Member Beowulf57's Avatar
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    Well now...ain't this neat!

    This is the first time in around 50 years that I have seen any other cabinets identical to those I am using! Where did you get them...did you build them? Do you know the origin or who made them?

    My left channel (D131) and right channel (D130) cabinets are identical except that the outside height of the D131 cabinet is 27.625", the D130 cabinet is 29.125". So, the larger driver has a 1.5" taller cabinet. The driver mounting method is also different: D131 is mounted to a brass ring with about 2" of mounting area all around and this ring is then screwed into the solid 5/8" hardwood ply front of the cabinet; D130 mounted to a 5/8" solid hardwood baffle that is screwed onto two metal side plates using machined decorative bolts into captive nuts.

    As to which driver to use, that depends on a number of factors. These cabinets were originally designed to use extended range drivers such as the JBL D131, D130 or the EV Wolverine. That's the reason the driver feeds a back-loaded horn and also fires forwards. The crossover between the horn and the front radiation is probably somewhere around 180-220Hz, but I've never measured it precisely.

    I'm assuming you want to use the extended range of a D131/D130 and depending on the exact dimensions of your cabinets, they might have been built with either 12" or 15" drivers in mind. To my ears, the D130 is more powerful and open sounding than the D131 (the driver is about 2dB more sensitive), however the D131 may have a slightly more "solid" sound in the lower bass. There is a bit of difference in the tonal character of the bass, but this does not adversely affect the sound and is not at all noticeable when listening to music.

    Are you planning to extend the system with drivers such as the LE85 and 2405?

  3. #3
    Senior Member spkrman57's Avatar
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    My intended application...

    Quote Originally Posted by Beowulf57 View Post
    This is the first time in around 50 years that I have seen any other cabinets identical to those I am using! Where did you get them...did you build them? Do you know the origin or who made them?

    I have been collecting audio gear and speakers for approx the last 20 yrs. Most of what I picked up was due more to being in the right place. I found these BLH cabs about 8 yrs ago from a friend of mine who deals audio F/T and he found no real value in these for resale, but he knew I liked old vintage speakers and he picked them up for me cheaply.

    Lately, I have been working on my home repairs and found it necessary to get rid of quite a few old speaker cabs. These are part of what I kept once I started selling/pitching things to make room.

    My left channel (D131) and right channel (D130) cabinets are identical except that the outside height of the D131 cabinet is 27.625", the D130 cabinet is 29.125". So, the larger driver has a 1.5" taller cabinet. The driver mounting method is also different: D131 is mounted to a brass ring with about 2" of mounting area all around and this ring is then screwed into the solid 5/8" hardwood ply front of the cabinet; D131 mounted to a 5/8" solid hardwood baffle that is screwed onto two metal side plates using machined decorative bolts into captive nuts.

    As to which driver to use, that depends on a number of factors. These cabinets were originally designed to use extended range drivers such as the JBL D131, D130 or the EV Wolverine. That's the reason the driver feeds a back-loaded horn and also fires forwards. The crossover between the horn and the front radiation is probably somewhere around 180-220Hz, but I've never measured it precisely.

    I'm assuming you want to use the extended range of a D131/D130 and depending on the exact dimensions of your cabinets, they might have been biuilt with either 12' or 15" drivers in mind. To my ears, the D130 is more powerful and open sounding than the D131 (the driver is about 2dB more sensitive), however the D131 may have a slightly more "solid" sound in the lower bass. There is a bit of difference in the tonal character of the bass, but this does not adversely affect the sound and is not at all noticeable when listening to music.

    I see using a JBL 2225H and Altec 902/811B and crossover TBD later. Crossover building is easy enough for me to accomplish. My pair of D131/2202 recones have a fs that keeps me thinking the LF response might be a bit thin. Of course, that is always subject to change!

    Are you planning to extend the system with drivers such as the LE85 and 2405?

    I plan to keep it a simple 2-way if possible!
    Regards, Ron
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  4. #4
    Senior Member spkrman57's Avatar
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    Funny you worded it that way!

    Quote Originally Posted by Beowulf57 View Post
    This is the first time in around 50 years that I have seen any other cabinets identical to those I am using!

    Actually, yours is the only other ones I have found/seen. I tried searching many places trying to identify them.

    They also look similiar to a Tannoy type back-loaded horn type(but missing additional folding).

    Is there any info on the web you were able to find that gives more info about these?

    Mine were built at different times according to the finish on both. One of the baffle boards had a cutout for a cone tweeter, the other did not. Both baffle boards are made for 12" driver. One of the cabs had a really lame Quam 12" with whizzer cone in it. I'm not flaming Quam as they made some really good drivers, this was the economy part of the line.

    Ron sends...
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  5. #5
    Senior Member Beowulf57's Avatar
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    Ron: I have never been able to find any information or plans of these speakers. My father (Ross Cann) did not keep the plans and for all I know he designed them himself? The D131 version was made by a friend of our family Henry Northcote who was the head of the machine shop at Raytheon Canada (my father was the president), the D130 by my father. He completed the major construction and I did the baffle board and finish work.

    The design is an exponential folded horn with a loading chamber feeding the throat of the horn.

    "I see using a JBL 2225H and Altec 902/811B and crossover TBD later. Crossover building is easy enough for me to accomplish. My pair of D131/2202 recones have a fs that keeps me thinking the LF response might be a bit thin. Of course, that is always subject to change!"

    The 2225H is about 6dB less sensitive than the D130, however the Altec 902 is also less sensitive than the LE85, so I would expect level matching should work out just fine. Will you be using the version of the 902 that reaches down to 500Hz, or the 1200Hz model? I have tried my LE85s with the higher 1200Hz crossover and much prefer them at 500Hz for overall system balance...but this may be a function of peaking response from the D131/130 when used up that high. Likely different with the 2225H.

    Why not just pop the D131s into the cabinet and see what the response is like when the cabinets are placed in the corner? I actually listened to my speakers with just the one driver for 10 years before I added the LE85s in the mid 80s. Quite listenable...though nothing like the presence, articulation and mid-range clarity with the compression drivers on top.

    Douglas

  6. #6
    Senior Member spkrman57's Avatar
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    When the time permits...

    Quote Originally Posted by Beowulf57 View Post
    Why not just pop the D131s into the cabinet and see what the response is like when the cabinets are placed in the corner? I actually listened to my speakers with just the one driver for 10 years before I added the LE85s in the mid 80s. Quite listenable...though nothing like the presence, articulation and mid-range clarity with the compression drivers on top.

    Douglas
    That will be what I plan to do. I have a older Eico audio generator that I can use to sweep tones and use my ears to see what the driver does mounted on the baffle board only, and then in the cabs placed in the corners.

    Thanks a lot for the info and advice!

    Regards, Ron
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  7. #7
    Senior Member Beowulf57's Avatar
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    Quote Originally Posted by spkrman57 View Post
    That will be what I plan to do. I have a older Eico audio generator that I can use to sweep tones and use my ears to see what the driver does mounted on the baffle board only, and then in the cabs placed in the corners.

    Thanks a lot for the info and advice!

    Regards, Ron
    You are most welcome...I look forward to hearing the results of your experiments. I may set up my own Eico 379 when I have a moment and run a similar test.

    For a chuckle: recently I was using the Eico to test one of my LE85s that had a distortion problem. I was getting all sorts of odd sounds as I swept the audio spectrum from 500Hz up...gee, I thought, there must be a real problem with the diaphragm?! Then I remembered that the 600 ohm output impedance signal generator was not really designed to drive an 8 ohm load!! I was asking an output stage capable of say 15ma to provide around 250ma.

    Best wishes,

    Douglas

  8. #8
    Senior Member spkrman57's Avatar
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    Eico Model 377

    My Eico is tubed and still even though designed for 600 ohms does a adequate job of providing enough signal to tun sweeps on most medium to high efficiency cone speakers.

    I'm actually working on hooking up a driver in the cabs this morning.

    I will report my (less than professional) findings later.

    Ron sends...
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  9. #9
    Senior Member spkrman57's Avatar
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    Good news and bad news...

    Well I could not use the JBL D131/2202 since I did not have a front gasket on it and I needed to mount the driver on the back side of the baffle board.

    I found a Utah 12" that is like a poor mans version of the Altec 414. It would fit behind the baffle board with no problems.

    So with the driver mounted on the baffle board I ran a sweep from 200hz to 20hz, and then did the same sweep with the baffle board installed to the horn cab in the corner.

    My results of the horn loading range were approx 90hz to 180hz being the predominant bandwidth. Of course I used a bedroom to do this test as the only corner I could use in the house. I think I like this design with a powered sub filling out the bottom end.

    I want to modify one of the baffle boards and try out the 2225H 15" driver as I see the potential for a more full-bodied sound might be possible.

    Time to shovel some snow before I can play again. I hope to know more by next week.

    Regards, Ron
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  10. #10
    Senior Member spkrman57's Avatar
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    Added note...

    I took the horn path length of (approx) 40" and using my hillbilly technical math formulas and came up with 85 hz as the bottom end cutoff(not counting the walls extending the final flair).

    I can see where the corner walls would help efficiency here, but not much more in the LF section.

    Still I see using a Altec 902 on a 811B horn(notice how similiar the 811B baffle size is compared to the folded horn baffle!). I will make new baffle boards for the D131/2202 drivers, and a bonus is I can locate the 12" driver up as high as possible to be close to the 811B horn.

    I would use Pi crossover @ 1.6khz with att/EQ built in. Add the powered sub and sounds like a really neat 2.5 way (2 subwoofers-but in mono)

    Ron sends...
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  11. #11
    Senior Member spkrman57's Avatar
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    Pics of crude hillbilly testing facility!

    This is almost like our grandparents and parents built things back in the day before computers and T/S specs were available!

    Install the driver, sweep the audio generator and let your ears tell you what it's doing!!!

    The driver on top of the cabinet face down is the same as the one installed for the quick test. Fs is approx 40hz. I did not test these, but I have several of this model type and they usually measure fairly close.

    The cone tweeter is a sealed back and is used only to cover the empty hole. And the ashtray only holds screws/bolts and nuts since I quit smoking last Apr 2009!

    Note: My horns are not pretty like Beowulf57's, but if the system ends up sounding good enough, they will be refinished!

    I need more room to do these projects. I'm still working on a older EV 4-way that horn-loaded a 18" and a 8" cone drivers, then compression drivers on horns for the HF and VHF. They had a Georgian 400 crossover mounted in them, but I have not found this model anywhere on the web yet. I got the cabinets empty of drivers and crossovers, but I like to try out my own designs to see how close I can get without much computer help.

    Both of the corner-loaded horns EV and BLH's are in the same bedroom. And the EV's are twice the size!

    Regards, Ron

    Regards, Ron



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  12. #12
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    Quote Originally Posted by spkrman57 View Post
    This is almost like our grandparents and parents built things back in the day before computers and T/S specs were available!
    Our grandparents still had Physics....... it wasn't all trial and error.

    That's a nice looking horn........ makes me want to build something.

  13. #13
    Senior Member Beowulf57's Avatar
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    Quick update: I searched and searched through piles of papers and documentation going back over 50 years, and...found plans for the back-loaded folded horn! I will scan and post as soon as I have time.

  14. #14
    Senior Member spkrman57's Avatar
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    That sounds like a great idea!

    Quote Originally Posted by Beowulf57 View Post
    Quick update: I searched and searched through piles of papers and documentation going back over 50 years, and...found plans for the back-loaded folded horn! I will scan and post as soon as I have time.
    I will do more testing on different drivers in the back loaded folded corner horn system.

    I'm curious of the paperwork you have on these horns...

    Ron sends....
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  15. #15
    Senior Member Beowulf57's Avatar
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    Here's the scan.
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