Large format Coaxial designs

[cclark65]

I know this doesn't pertain much to the old Altec, but can anybody tell me what effect the larger horn has when placed in the mouth of the bass horn, such as in this Altec cabinet: http://www.altecpro.com/pdfs/DE6412_SS.pdf

I was thinking about building a cabinet similar to that, and using my MRII64 horns with 299 drivers on it. I know the driver will come close to the woofer, but maybe that will help a little as if it were a phase plug?

4 of those per side might sound pretty sweet.

[LICORNE]

Hi there,

What model woofer are you planning on using?
If it's 416 ,515 etc. Those are HI FI components.

The DE system is a PRO DUPLEX system for venues.
Not HI FI; With High power wattage requirements.

I believe they sell for 3000$ each. A little steep
according to some experts.

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[cclark65]

I am not going to use them for hi-fi, that's not a problem. I have my 14's and 604's for that. Either them or I have a few 511b's in the garage with 902's on them that I can bring in and build bass cabinets for them.

I do a lot of live PA work, and just wanted to play with the design. Right now I have a pile of 421's that I could recone as 515's, but I am going to be more inclined to use my EAW's in them. I bought a dozen from a sound company that upgraded theirs to 600 watt drivers, and they sold me these 400 watts 12" drivers for 100/pair. They came out of horn loaded cabinets and handled the bass from about 100 to 1000 anyway. I figured if I could get a better point source, then I would be able to get better clarity. Right now I have all separate cabinets, and it sound great from 10 feet back to 150 feet or so, but up close it ***** because the bass driver is 2 feet away from the horn driver. Plus I want to use the 60 degree horns that I have on the shelf in the garage instead of the 90 degree ones for better control and less comb filtering.

Here are some photos here from this past weekend if you are interested in seeing what I use them for.
http://www.acsnet.com/~ultimate/pics/Edgefest06/

I know they aren't setup ideally, but I have to work with what I have! The subs are 4 dual 18's laying on the ground under the lip of the stage, you can't see them in any of the photos.

[Old Guy]

Hi Charles-

Sounds like you got a heckuva deal on the EAW speakers. If you have part numbers I'll try to let you know exactly what you have. Most likely you have RCF. But their market value is probably at least double what you paid.


RCF copied JBL technology in the beginning, before they developed their own.

Convergence- are you thinking EV instead of EAW? These are most likely overhung coils if they are RCF.

[LICORNE]

Hi there,
No the EAW are overhung . That is why I'm recommending 515 8GHP instead.

I'm also recommending a stage truss box for heavy equipment.

http://www.globaltruss.com/product.a...mber=214&cat=8

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[Old Guy]

Hi Charles- sorry my brain faded in the middle of that last post.

You were asking about mounting the horn coaxially. I've seen it done, sometimes well sometimes not. This kind of box has faded in and out of favor a few times.

A horn is designed to expand at a certain rate. A small horn probably wouldn't interfere much. A very large horn might. If you're going to copy an existing design, changing to a much larger horn would probably throw it off.
It would be easy to figure the volume of the horn and compensate when building the mid bass horn.

Community made some coaxial type horn systems. Ev made some in their theatre line, they weren't bad but didn't sell well.


Of course the proof of the pudding is in the eating. You may just have to build the darn things and see how you like them.

[LICORNE]

Hi There,

For 100$ a pair you got a good deal. Like I said previuosly use them as fill ins ,Match them with your mains.

THese are DE the same as DX series. I never heard of Ev making that type of speaker.JBL and Ev made some coax but no DTS with the elongated horn ,Big difference here.
I'm trying to be precise in my description product and helpful as possible.

OldGuy you should catch up on the DTS systems by Altec in the unofficial Web site.No Criticism .

Keep smiling

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[Old Guy]

Quote: THese are DE the same as DX series.

I have no idea what you are talking about. Please explain.


Quote: I never heard of Ev making that type of speaker.JBL and Ev made some coax but no DTS with the elongated horn ,Big difference here.

I said absolutely nothing about an elongated horn. I said EV made coaxial horn enclosures. They did.


Quote: OldGuy you should catch up on the DTS systems by Altec in the unofficial Web site.No Criticism .

What makes you think I don't know about those speakers? The original post was about a coaxial horn enclosure.

The recommendation of 515's for a live sound midbass I have to go on record as being against.

There simply is no reason to use a 15" cone. 12's are a much better idea. The EAW (probably RCF) are going to work much better.

Frankly, I'd use 421's as midbass for live sound way before I would consider 515's.

[Old Guy]

I think I'm beginning to see some of the confusion convergence- you are talking about the Altec boxes. I'm not- Charles is talking about putting the HF horn inside the midbass horn. While this is a coaxial horn, it's not a coaxial driver.

I still suggest using the EAW 12's for midbass. I typoed earlier. The EAW/RCF speakers are probably underhung, not overhung. Age does things like that.

[Old Guy]

Hi Charles- here's one of the EV coaxial horns. Photo doesn't show much, there's a drawing on the last page.


http://www.electrovoice.com/Electrov...e/38110124.pdf

Is this the sort of thing you want to do?

Where are you thinking of crosssing from low to mid bass? I like to keep this point as low as possible, usually between 80-115 hz.

Actually I use an auxillary mix(post eq) to feed the subs. This lets me put only what and how much I want there. The vocals go through the main stacks only. (Mid bass up) Have been doing this for about 15 years , works well for me. Does use up an aux on the board but I've got extras.