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Decware Imperial horn drivers ? (Read 1847 times)
TomR
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Decware Imperial horn drivers ?
06/11/19 at 18:53:46
 
Hello Forum,
I am considering building a set of the Decware Imperial folded horns.
I have read what I could find on the subject, but still have a few questions.

What T/S parameters work best in this horn configuration ?

I read using two different 15" driver offers some benefits. If yes,
does anyone have real world experience with this ? Drivers used ?

Reading the Imperial information, the horn can be used up to 600 Hz with the proper driver. My interest is running it up to 500Hz.  Anyone have any specific driver that accomplished to goal ?




Thanks,
Tom R
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Archie
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Re: Decware Imperial horn drivers ?
Reply #1 - 06/12/19 at 00:56:37
 
Why don't you ask Steve?  I'm sure he'll give you the most direct and likely best answer.
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Steve Deckert
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Re: Decware Imperial horn drivers ?
Reply #2 - 06/12/19 at 01:14:02
 




First of all I haven't put anything in the Imperial horn that I didn't like and I've tried a lot of things.  Everything you put in one sounds better than it will in anything else.  Very forgiving.  My only advice is don't waste the horn by using drivers with a high FS.  If the driver only goes down to 45Hz on a good day, the horn is only going to impress down to about that frequency.  You could get just as good a result in 1/2 the size horn if you only want 45/50Hz.

There are no advantages to two drivers unless you use it for PA use.  

An Altec 604 is a tasty and simple solution for an Imperial that is easier to find than the original Jensen G-610 driver.

Altec 420A BiFlex is pretty wicked in an Imperial.

Altec 416-8A is a favorite when you plan to use a midrange/high frequency drivers with it.

New stuff, Just look at pro audio drivers and find ones that go down to 30Hz or below.

-Steve



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TomR
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Re: Decware Imperial horn drivers ?
Reply #3 - 06/12/19 at 18:41:35
 
Thank you for the response and information, That helps a lot.

I am aware of the Altec 416 driver.

I do have TWO, pairs of 15" drivers available to me:

First Pair: Eminence 15" Magnum LO drivers with the following published specs:

Fs: 37Hz
Qts: .45
Qms: 9.4
Qes: .48
Vas: 5.76 cu ft
Xmax: 7.9mm
Re: 4.9


Second set of 15" drivers, Eminence 15" NOS, not sure of the model, but measures T/S parameters are:

Fs: 27
Qts: .166
Qes: .169
Qms: 9.4
Vas 8.2 cu ft
Xmax .359"
Re: 7.6
94 db
200 watts
This driver has a usable FR to 800 Hz

Any opinion on the above drivers ?

The Altec may give additional mid band response to allow better intergration with the mid range horns I am building. Hope to use the bass bins up to 500 Hz, crossed to the mid horns

Tried to attached a few construction pics of the mid range horns I am building. usable frequency for the horns is 500 to 3,500 Hz
Not sure if the pictures were uploaded or not.....?  


Tom R

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Mid_construction_1.jpg
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Steve Deckert
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Re: Decware Imperial horn drivers ?
Reply #4 - 06/12/19 at 23:49:33
 
The second set that goes down to 27Hz would be my choice between those two.  Ambitious horn project!  Nice!
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TomR
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Re: Decware Imperial horn drivers ?
Reply #5 - 06/13/19 at 02:18:18
 
Thanks - Yes, the mid horn are taking some time to fabricate

Need to learn how to down size pictures......

That should have been the obvious choice as the Eminence Fs does not go low enough to get into the 20's

Just for my knowledge, are you not concerned about the very low Qts, and the drivers ability to reproduce the 1st octave in a large enclosure ? Or, is the horn such a good acoustic impedance matching device that a high Qts is not a concern ?

Please advise,
Tom in Lafayette
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Brian
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Re: Decware Imperial horn drivers ?
Reply #6 - 06/13/19 at 04:54:37
 
Hello Tom,
To down size pictures, IrfanView is a free to download image editor I use a great deal. I find it reasonably intuitive and self explanatory to use.

I like your horn project.
Brian
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TomR
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Re: Decware Imperial horn drivers ?
Reply #7 - 07/13/19 at 15:11:23
 
Mr Steve,
If I only use one driver per cabinet, should I decrease the size of the enclosure, or keep the same dimensions as the plans ?

Purchased your Imperial plans the other day, when I finish my mid range horns, I will start on the Imperials


Tom in Lafayette
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Steve Deckert
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Re: Decware Imperial horn drivers ?
Reply #8 - 07/18/19 at 01:02:22
 
To use a single driver with the Imperial plans, keep all dimensions the same.

Also, a new driver by Lii-Audio called the F15 would be outstanding as a full-range driver in the Imperial.

-Steve
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TomR
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Re: Decware Imperial horn drivers ?
Reply #9 - 07/19/19 at 02:56:54
 
I have read the Big Betsy Thread with interest. Your description of the speaker is enticing. The F15 has a FS of 49, so if used in the Imperial cabinet, it would not reach the lowest octave.

Would this make a good case for two different drivers in one cabinet?
The F15 and a 15” sub driver that could cover the lower frequencies?

Run the F15 at full range, with a simple high pass on the sub-woofer….something like that ?
A plate amp on the sub-woofer, cut off at 80 Hz to the F15 running full range on a separate amp?

Could they operate out of the same cabinet without issue?


Tom in Lafayette
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Steve Deckert
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Re: Decware Imperial horn drivers ?
Reply #10 - 07/19/19 at 17:50:36
 
Again,  the dual driver arrangement is more for PA use, as the two drivers do not usually help themselves sound better as an audiophile will expect.  While the FS is 49Hz, the driver will play lower than that with a well controlled roll-off.  My recommendation with this driver is to run it by itself and do not worry about low bass augmentation until after you actually hear what it does.  This isn't one you can model or predict.

Steve
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TomR
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Re: Decware Imperial horn drivers ?
Reply #11 - 07/19/19 at 17:59:39
 
Understood - Thanks
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TomR
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Re: Decware Imperial horn drivers ?
Reply #12 - 08/05/19 at 18:06:45
 
Took the leap - I ordered a pare of the F15's for the Imperial build.

I am out a month or so to start the cabinet build, but will post build information as I proceed


Tom in Lafayette
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FarmBoss
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Re: Decware Imperial horn drivers ?
Reply #13 - 08/06/19 at 01:58:21
 
Tom

I am doing the same thing.  I have the f-15`s but nowhere to build until a month or two down the road.  We should start a thread on our experiences.  I took a look at the plans todat and they are for double drivers so some (UNCLEAR) adjustments will need to be done
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TomR
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Re: Decware Imperial horn drivers ?
Reply #14 - 08/06/19 at 21:34:02
 
That sounds like a plan, I am also a month or so away from starting the Imperial build.
I have to finish a mid-horn build I have been working on and off since Christmas before I start another project.

I believe you will simply adjust locations of the internal braces to accommodate a single driver in the center location. Will look at the drawings again.

Where are you located ? I am in South Louisiana.


Tom in Lafayette
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TomR
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Re: Decware Imperial horn drivers ?
Reply #15 - 08/08/19 at 02:04:05
 
FarmBoss,
Looking at the Decware drawings, I would propose substituting the center solid "B" style for a "A" style brace with the cut out for a driver. So that would mean you need to fabricate 3 of the "A"style, and 2 of the "B" style.

My best guess at the moment.......


Tom in Lafayette
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FarmBoss
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Re: Decware Imperial horn drivers ?
Reply #16 - 09/17/19 at 02:55:48
 
TomR,

Started my Imperials today.  I bought 5 sheets of birch ply to start.  I will make one speaker then the other.  It is not easy cutting such large parts without a panel saw.  Used my tablesaw and circular saw.  I have two sides done.  Let me know when you start I am struggling with measurements based on the blueprints it is hard to tell if the back sits on top of both bottom and below both tops.  I figure it sits on the first bottom and below the first top. I seriously considered doing a scaled down Imperial or https://www.speakerplans.com/index.php?id=18superscooper
I decided to go all in and just pony up for the whole imperial.  It seems like there is a lot of waste and bugs me I can't get more than one side out of a 4x8 sheet.

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Steve Deckert
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Re: Decware Imperial horn drivers ?
Reply #17 - 09/17/19 at 03:15:52
 

Congrats on the Imperial build!  

Using the "A" style brace for the center is what we do when these are built for a single 15 inch driver, and then modify the front panel accordingly.

Quote:
I figure it sits on the first bottom and below the first top


Yes, this creates a joint with more surface area enhancing the strength of the glue joint.  

Waste is easy to deal with as you begin to complete the cabinet you can find so many places to add cleating and braces.  Just use the waste to further beef up the cabinet.



Steve

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TomR
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Re: Decware Imperial horn drivers ?
Reply #18 - 09/17/19 at 18:38:05
 
FarmBoss,
No, I have not started my Imperial build yet, I do have a set of F15 drivers to try when they are ready !

I have two different options for the Imperial cabinets, one with the F15 drivers, and the second with a Eminence 15" woofer to 500 Hz - Multi cell Mid range horn driven by a JBL 2446h compression driver from 500 to 3500, then a compression tweeter to be named.

For now I am trying to finish the Mid range horns before I start the cabinets. I must say I have been tempted to build a Big Betsy with the F15's to see how they sound.............


If you come across any issues during the build - please post the question, or how you figured out a construction issue


Tom in Lafayette
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Brian
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Re: Decware Imperial horn drivers ?
Reply #19 - 09/18/19 at 04:57:10
 
Tom, If you build one cabinet with the single driver, and one with the three way, and compare them to find which you want to go with; that would be an interesting comparison.

Brian
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TomR
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Re: Decware Imperial horn drivers ?
Reply #20 - 09/18/19 at 18:07:24
 
FarmBoss
Check out “DIY track saw” on You Tube. One of these will help you break down sheet goods, with a straight edge


Tom in Lafayette
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FarmBoss
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Re: Decware Imperial horn drivers ?
Reply #21 - 09/20/19 at 01:21:27
 
Ok I have a question on reading the plan.  It says part D x 2.
Does this mean the two seperate braces or does it mean make them double thick?

I am assuming we are still wourking with 3/4 stock.  The braces as shown on the left (front) diagram sjow two D braces but appear to be about triple the width of a 3/4 part.  
plan says 1 to 12 ratio.  That can't be right as it would equal nine inches wide.

So bottom line, what it the depth or maybe the width of part D?

Thanks
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TomR
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Re: Decware Imperial horn drivers ?
Reply #22 - 09/20/19 at 15:59:09
 
Farm Boss,
I am away on holiday and only have my IPhone with me, and do not have access to my set of plans. I will be home next Wednesday and will look then, hopefully that will not hope hold you up


Tom in Lafayette
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FarmBoss
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Re: Decware Imperial horn drivers ?
Reply #23 - 09/25/19 at 03:24:08
 
I worked all weekend and have almost fin8shed the first one.  As far as the brace D goes I have decided it is three 3/4 ply wide.  Now I am wondering about the optional brace E.  I think it should only be one 3/4`s wide but maybe 2?

I don`t know if this is the first Imperial with the F-15 driver ever made?  I have it hooked up to a Fischer console in my workshop.  The Fischer is 20 watts.  At first I was a little underwelmed.  It sounded a bit bright and shouty.  It was also lying on it's side.
Something really cool happened after 3 hours or so.  I put on Santana and turned the volume up pretty good.  The sound changed and it was quite remarkable.  This speaker hooked up to that old amp really rocked.  I have not heard the low notes like this on any home system.  I have had a few subs and this 8s nothing like those.  The bass and kick drums sounded real and loud but not at all muddy or thick.  THESE ARE REALLY GREAT SPEAKERS! I can only imagine how great two of them will sound on my ZMA systerm.  This is on a stereo I paid $98 for.  Incredible Smiley



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Steve Deckert
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Re: Decware Imperial horn drivers ?
Reply #24 - 09/25/19 at 03:34:02
 
Nice... : )
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TomR
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Re: Decware Imperial horn drivers ?
Reply #25 - 09/25/19 at 18:02:00
 
FarmBoss,
Having a look at the drawings and optional brace "E", you will need two pieces at 3/4" thick, I believe the "E" braces are mated to the forward edge of the side panels, as you look at the front of the speaker cabinet.  The double of the forward edge thickness will help stiffen the large side panels.

At least that is what I see.....

I need to get my F15's up and running so they will be broke in when I get the Imperial cabinets built......


Tom in Lafayette
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