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Multi-Way Conventional loudspeakers with crossovers

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Old 30th May 2017, 05:52 PM   #1
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Default Won Horns @ LSAF - help me do something worthy with them

So I'm very much a novice when it comes to building speakers and need some help. For those of you that attended Lone Star Audio Fest, I'm the lucky guy that won the horns from Pi Audio (pictured below).

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Click the image to open in full size.


Its been a few weeks since Lone Star and things have settled down, so now its time to start figuring out how to do these horns justice.


Here is a little background on things to help:

Horn info: They were made by Bill Martinelli and they’re 800Hz horns with a conical throat and hybrid expansion. They’re not CD, but relatively close, and benefit from mass-rolloff compensation just like CD horns do. They mount a standard bolt-on 1” driver.

My room: I do not have 2 corners and it is fairly small. It is 10' deep x 14' wide with the rear wall being 38" tall and overlooking the entrance. So I cant do corner loaded horns, or large boxes either.

Wayne Parham and I exchanged some emails and he suggested some drivers to me. For the tweeter I think I am going to go with the B&C DE250-8 but am open to suggestions.

What I'm struggling with is what driver to use for the low-end/midrange driver, and MOST importantly how to build a crossover. Wayne suggested the Eminence Definimax 4012HO 12” driver, but I want to make sure there isn't anything out there better. He also suggested that whatever I choose be a high-efficiency 10” or 12” driver that is capable of smooth response up to 1500Hz or so

My goal is to build a 2 way speaker with the horn on top with a ported box for the bottom end. That ported box will be using a driver in the 10-12" range in a form fairly compact box that can dig down to around 40hz.

I spent most of last night looking at and I was either finding drivers that would dig deep enough but had low sensitivity (like the regular 8 ohm Tang Bang full range drivers), or ones with really high sensitivity but wouldn't go that deep.

As I'm not super good with WinISD modeling the every possible driver as I was looking at them wasn't an option from a time or technical perspective....

My goal is that the resulting speaker has a sensitivity as high as possible to allow for use with flea power amps, such as tubes, or Class A solid state amps, but housed in a fairly compact box.

The horn is 17" wide x 5.5" tall x 10.5" deep so at min I wanted to try and keep the box size barely wider than the horn's width, and also a bit deeper than the horn as well to account for the depth with the tweeter mounted to it.

So in thinking of box size, I was hoping for a driver that would work in a box along the lines of 17-19 inches wide x 15-20 inches tall x 10 - 12 inches deep in a ported box....

This morning I remembered that DIYSoundGroup has a bunch of kit options and most of them use waveguides, but more importantly larger pro drivers in fairly small-ish boxes....

So I started looking and found this gem of a kit which uses an off the shelf Eminence Delta Pro-12A...

The info on this kit says "The Tempest is vented and provides bass extension to 40hz (-3db) with a little extra kick in the mid and upper bass range"... and the flatpack for this driver is sized at: 14.5" x 26" x 14.25" deep, 2 cu ft net when used with ports

Now I realize this kit and what I'm doing are not exactly the same, however I think with some modeling I can play with that driver and get it to work for my setup.....

If I tweak the box size a bit as long as I keep the internals close and port it right I should be ok....

Alternately there is a smaller version of this same kit that uses the Eminence Delta-10A, so I may also play around with that driver. As configured that kit only hits 55hz and I'm guessing that it due to driver limitations, so the Delta Pro-12A may be the driver to pick.

I have no idea thought how I'm going to overcome the fact that both drivers will be 8 ohms, so I either have a 16 ohm load, which isnt ideal for any amp, or a 4 ohm load which may be a problem for a lot of amps.

Additionally I have no idea how to approach building a crossover to mate the two drivers together, so any and all help or feedback is appreciated.

I haven't bought anything yet so if I'm heading off on the wrong path, help me correct it now before I open up my wallet.
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Old 31st May 2017, 01:25 AM   #2
jimbro is offline jimbro  United States
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You'd probably have better luck on the multi-way forum but I would follow Wayne's guidance if it were me.
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Old 31st May 2017, 03:27 AM   #3
zobsky is offline zobsky  India
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Maybe buy a mindsp 2x4HD and go 2 way active -. If you have amps lying around

FWIW, I'm considering (haven't made up my mind) on selling mine in order to go 4 way active
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Old 31st May 2017, 04:20 AM   #4
frangus is offline frangus  Australia
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Flea power amps, medium sized woofers and deep bass dont go so well together
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Old 31st May 2017, 01:42 PM   #5
Pano is online now Pano  United States
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As stated above - if you want to use low power amps, use a large woofer. 12" minimum. Or give up some bass.

A horn and 12" woofer is a classic, it's easy to end up with a nice speaker. What's not so easy is horn crossovers.
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Old 31st May 2017, 01:43 PM   #6
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Quote:
Originally Posted by frangus View Post
Flea power amps, medium sized woofers and deep bass dont go so well together
In a room thats 10 x 14 empty, which it isnt so your more like 6 feet from the speakers if that, I'd hazard you wont need a ton of power to get more than adequately loud, especially when the drivers I'm looking at are 8 ohm 96db+ efficient.

Also I should mention I'm not focusing on just 6-8" drivers. My intent was to look mainly at 10 and 12" drivers, its 15's that get to be too big. That and the driver needs to fit into what I'd consider a smallish box (for that size of a driver). I'm not looking for a 4+ cubic foot box.

From what I seeing in WinISD the 12' Definimax 4012HO looks quite good in a 2.0 - 2.5 cubic foot box tuned to 40hz with a 2nd order highpass at 35hz. I'm showing 2 4" vents of 14" in length each keeping port velocity under 10 m/s. It can handle right around 150 watts before the driver gets into trouble, so since I plan on 100 watts max I will be fine.

The difference between 2 cubic feet and 2.5 from a SPL perspective is almost nill so I may go with the smaller box size just to save some space. I think I give up like 1db from 45hz down to 40hz.

Its still a bit pricey, but I dont mind hunting for a good bargain for a used driver, or waiting till Parts Express runs a deal on them.

If that's the route I go, once I get the driver in and the tweeter as well I will contact Wayne again to see if he's got a pre-configured passive crossover schematic for them already.

If not things will get tricky.

As far as going active..... thats not something I'm wanting to do at this point, though I can see the pro's of being able to tweak and build the crossover electronically for testing and tweaking on the fly, then building a REAL one once thats completed..... but thats hopefully not a route I have to go down.

Last edited by EndersShadow; 31st May 2017 at 01:48 PM.
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Old 31st May 2017, 02:01 PM   #7
Pano is online now Pano  United States
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The Fusion Tempest 12" looks like a great idea, if the cabinets are not too big for you. To get down to 50Hz and the mid to upper 90dB/watt is impressive. Of course you'll need to rework the crossover for your horns, or as you said, ask Wayne what he's got.
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Old 31st May 2017, 02:11 PM   #8
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Quote:
Originally Posted by Pano View Post
The Fusion Tempest 12" looks like a great idea, if the cabinets are not too big for you. To get down to 50Hz and the mid to upper 90dB/watt is impressive. Of course you'll need to rework the crossover for your horns, or as you said, ask Wayne what he's got.
I figure this is a typo, but the Tempest actually goes down to 37hz which is what really caught my eye.

I'm looking hard at that driver or just using the 12" Definimax Wayne recommends.... I need to work on modeling the Delta Pro in WinISD to see what I can do with it and compare to the Definimax. The Delta Pro is a bit cheaper too so thats a nice factor in play as well.

In doing some quick fast dirty math, a box that is 20 wide x 13 deep x 20 tall and uses 3/4" wood has internal dimensions of 18.5 x 11.5 x 18.5. That equates to 2.2 cubic square feet. After subtracting the driver, ports and some small amount of bracing, that likely gets me RIGHT to 2.0 cubic square feet....

With the horn on top, that gives me a final dimension of 20 wide x 13 deep x 25.5 tall which is I think an acceptable size for what I need.

The Tempest box size, which likely needs tweaking since the waveguide and compression tweeter wont be there taking up internal space, is 14.5" wide x 26" tall x 13.5" deep, and I'd likely lay it on its side and try to tweak out some of that width so its closer to the dimensions of the horn sitting on top.

I have this feeling I am going to end up with a almost 2 foot wide x 2 foot tall x 1.5 foot speaker size lol.....

The only thing I'm not sure of is if I need to have the ports fire front or back, or if I can have them fire out the side. If they have to fire out the front or back I'm going to end up with a speaker thats quite deep unless I do a 90 degree turn internally with the port which I think your supposed to avoid.

Last edited by EndersShadow; 31st May 2017 at 02:14 PM.
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Old 31st May 2017, 03:13 PM   #9
Pano is online now Pano  United States
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I was looking at the measurements of the 2ft box with the Delta Pro 12. Mid-band it's 95dB at 2.83V, which is impressive. If you take 95dB as reference, then it does play down to 40H, then rolls off fast. The bass bump above that will sound nice, but will be dependent on room gain. That's darn good for that size speaker. It's not small, but considering my old rig had 11 cu ft bass boxes (external), it's not a monster.
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Old 31st May 2017, 03:24 PM   #10
djn is offline djn  United States
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All the woofs mentioned will work well. If you have two amps, go with the MiniDSP. You can tweak the crossover parameters to fit your room much more persisly then messing with a passive. With those woofs and horn, going digital or SS on the woof and a small SET tube amp on the horn would be the nuts!!!
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