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Need suggestions for a lower range horn to mate with new Mid/High horns [message #59521]

Thu, 25 June 2009 14:56

noviygera
Messages: 23
Registered: June 2009
Location: United States

Chancellor

First off, hello to everyone and to Wayne. Wayne, I had the pleasure of talking to you once on the phone, probably a year ago. We talked about you constant dir. midrange horn. I made one, by the way.

This is my first post here.
I have a DJ/listening system in my basement. Mostly, self made.
(I had JBL 2470 for mids and 2405 tweeter)
Some pictures:
http://picasaweb.google.com/noviygera/BasementSystem#

Just recently i installed NEW Funktion-One RES 1.5HS horns.
(I believe I'm the first one in the US to have these!)
Pictures:
http://picasaweb.google.com/noviygera/FunktionOne#

My current system:
18" subs on H open baffles (Eminence drivers)
10" Rola on open baffles (really old drivers)
5" RES 1.5 HS (Funktion-One): 25v x 90h degree coverage.

Digital crossover by DBX Driverack PA, 200 HZ, 630Hz.
Eq is "flat" above 600Hz. RES 1.5 HS sound very good this way.
Some eq used for midbass(minor, +/-2db) and subs(some heavy eq below 100Hz).

At this point I would like to move to a mostly horn system, adding a midbass horn to cover up to 600Hz, where it will cross over to the Mid/High horn. I'd like to start by replacing the 10" Rola on open baffle.

So, I'm looking for a Mid bass horn to go up to 600Hz.
Should I make one or get a used one somewhere?
My priority is sound quality over output.

You may notice (in the second link above) I made one constant directivity horn, per Wayne's plans. But I made just one and I think it will not go down to 150Hz like I need.

TWO options I came up with:
The crossover point will be 530 to 600Hz. the RES 1.5 midhigh is 18" x 10" x 9" deep.

Keeping in mind, I'm trying to cover 600Hz and below... Given space constraints of a medium size basement room...

1st option is to get the 10N Pro midbass horn. It 17" x 21" x 10" deep. Freq resp: 250Hz-1.6kHz
http://www.ddshorns.com/catalog.php?page=DMB10NPro
I will then need to get an appropriate 10" mid, make a box and mount the midbass horn UNDERNEATH the Res1.5 midhigh. Seems reasonable.

2nd option is to get one of these: DVB 15H or DVB 15N Pro:
http://www.ddshorns.com/catalog.php?page=DVB15H
http://www.ddshorns.com/catalog.php?page=DVB15NPro
DVB 15H is 22" x22" x 5.75" deep, Freq resp: 60Hz - 1.25kHz
DVB 15N Pro is 22" x 22" x 15" deep, Freq resp: 60Hz - 800Hz
both will require a 15" driver instead of the 10" but size wise they are not that much bigger (5" taller)

...and to mount the the Res1.5 midhigh COAXIALLY, in the center of the big horns. Remember, the mid high mouth is 16" x 8", the mibass mouth is 22" x 22". Is this a GOOD IDEA? The question is will the midhigh create a shadow, or block the sound of themidbass driver and horn. It it worth emulating a single point source or will the drawbacks be to great?

Attaching a sketch of my concept. Will the directivity difference at 500 Hz cause a problem?

-Herman

Attachment: concept_horn.jpg
(Size: 86.31KB, Downloaded 441 times)

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Re: Need suggestions for a lower range horn to mate with new Mid/High horns [message #59522 is a reply to message #59521]

Thu, 25 June 2009 16:11

Wayne Parham
Messages: 18682
Registered: January 2001

Illuminati (33rd Degree)

Looks like you're having fun. Nice stuff!

The midhorn I use in the six π and seven π cornerhorns will get you down below 200Hz if used in corners, but it won't go that low out in the open. It's designed for home hifi use, where it blends with a woofer in the 100Hz to 200Hz range. The corners help, acting sort of like mouth extensions, because the midhorn is tucked into the corner so close to the side walls. Without corners, the mouth area is insufficient for output below about 250Hz. You'd need a larger horn for that.

I'd grab a copy of Hornresp and start playing with it. You can probably knock out a few models that look good in a short period of time. Myself, I'd prefer a straight horn rather than folded for use in the midrange. Folded horns are great below 100Hz, but once you're in midrange territory, I don't like them. Wavelengths are too short and you inevitably run into problems with standing waves.

Here are Hornresp models of a couple larger midbass / midrange horns I tinkered with a few years back:

9π midbass and midrange horns

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Re: Need suggestions for a lower range horn to mate with new Mid/High horns [message #59523 is a reply to message #59522]

Thu, 25 June 2009 16:26

noviygera
Messages: 23
Registered: June 2009
Location: United States

Chancellor

Wayne,

It's NOT possible to install horns near corners of the room. So no corner gain, but I wander if I can couple the midbass to the ceiling?

what do you think about my coaxial "horn within the horn" sketch? It's attached to the post.
The small horn would be mounted in the big horn. If crossed at 500 to 600 Hz would it work? dispersion problems happening here?

Theoretically, the midbass horn would be 18" wide, like the high horn, but tall, about 35" high, coupled to the low ceiling of my basement.

-Herman

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Re: Need suggestions for a lower range horn to mate with new Mid/High horns [message #59524 is a reply to message #59523]

Thu, 25 June 2009 16:44

Wayne Parham
Messages: 18682
Registered: January 2001

Illuminati (33rd Degree)

I understood you cannot use corners. I find most cases, corner loading isn't an option. I merely mentioned it to clarify that the midhorn used in the six π and seven π loudspeakers is actually too small to be used in freespace.

The main thing I wanted to show was the link to the earlier thread with a couple of Hornresp models and brief instruction how to model a horn. You could perhaps use that as a starting point.

Coaxials have never held my fascination because they solve one problem by causing another that I think is worse. Whatever you do in a coaxial arrangement, something is compromised. Usually the inner horn is too small, and suffers poor loading and pattern control. This gives ripples on and off-axis. If the inner horn is made large enough, it tends to obstruct the outer horn, leaving a hole in the pattern on-axis. Some configurations have been used that pack a driver or array of drivers along the side walls, but this creates multiple reflections and even in its best trim, it's really hard to get the summing right. Any shifts cause whatever alignment is provided cold to be misaligned hot. So none of these kinds of coaxial or coentrant arrangements are very attractive to me.

There is one thing that a coaxial or coentrant horn does well, one problem it solves. There is no vertical offset between the sound sources. So if you need a tall vertical pattern, you have the possibility to get one using a speaker arrangement like this. The thing is, I can't see much use for a tall vertical pattern and the price you pay to get it takes that option off the table for me. But if you need tall vertical coverage, it might be useful. It also makes for nice convenient packaging.

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Re: Need suggestions for a lower range horn to mate with new Mid/High horns [message #59525 is a reply to message #59524]

Thu, 25 June 2009 17:58

noviygera
Messages: 23
Registered: June 2009
Location: United States

Chancellor

I see your point, Wayne, thanks for replying. I will do some measuring and post sketches of two more options I thought of.
In brief, one idea is to mount the midbass above the mid/high right under the ceiling (touching the ceiling), horn loading the ceiling from 150 to 600 Hz.
The other (coaxial) is to make the midbass horn large enough to accomodate the midhigh horn inside being offset from the midbass center vertically. So the midhigh will be inside the midbass, but above the throat level of the midbass, leaving the midbass driver unblocked from view. But this would, make it unnecessarily wide dispersion vertically.

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Two midbass horn layouts... [message #59563 is a reply to message #59521]

Tue, 30 June 2009 21:25

noviygera
Messages: 23
Registered: June 2009
Location: United States

Chancellor

While trying to figure out HornResp, I came up with two midbass horn layouts. The question is weather they will work in my setup, so I included both sketches.

1. Midbass ABOVE the midhigh, coupled to the ceiling: available area: 12"x34" mouth, 30" depth.
(option1.jpg)
index.php?t=getfile&id=38&private=0

2. Midbass VERTICAL, below the midhigh. I was inspired by this JBL horn:
http://www.jbl.com/home/products/product_detail.aspx?prod=1400%20ARRAY%20BG&Language=ENG&Country=US&Region=USA&cat=BFS&ser=PTS

Can this be made to cover 90 deg horiz x 25 deg vert? By stretching out the throat to be tall and narrow?
(option2.jpg)
index.php?t=getfile&id=39&private=0

Thank you.
Herman

Attachment: option1.jpg
(Size: 311.38KB, Downloaded 8347 times)
Attachment: option2.jpg
(Size: 250.83KB, Downloaded 7533 times)

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Re: Two midbass horn layouts... [message #59565 is a reply to message #59563]

Tue, 30 June 2009 22:02

Wayne Parham
Messages: 18682
Registered: January 2001

Illuminati (33rd Degree)

There are a lot of ways to skin a cat. But as for me, I try to keep the sound sources above the Schroeder frequency spaced so they sum constructively through a fairly large vertical arc which means relatively tight vertical spacing. The crossover should be designed with the same goal, to provide a large forward lobe with widely spaced vertical nulls. Naturally, you want to have the same horizontal coverage from each sound source so directivity and spectral balance is uniform along the horizontal plane. I say naturally, but I guess that isn't a given. That's just one of my priorities.

Below the Schroeder frequency, the sound sources can be (read that should be) spread out a little more to smooth out the room modes. So I guess my vote would be to use a midrange that blended with your woofer in the upper modal region. Keep the woofer low-pass under the Schroeder frequency, but let the midrange run down as low as possible for good blending. You can't do that if power levels are high like for prosound, but in that case you probably wouldn't have room modes to contend with so the tradeoffs would be different. For home hifi and home theater, I think it's a good way to go.

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Re: Two midbass horn layouts... [message #59566 is a reply to message #59565]

Tue, 30 June 2009 22:08

noviygera
Messages: 23
Registered: June 2009
Location: United States

Chancellor

So, Wayne, do you believe any of the two options would work? I couldn't figure out if you are against both options, in which case I assume I would have to mount the midbass, between the highs and subs. Please clarify.

Thanks,
Herman

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Re: Two midbass horn layouts... [message #59567 is a reply to message #59566]

Tue, 30 June 2009 22:18

Wayne Parham
Messages: 18682
Registered: January 2001

Illuminati (33rd Degree)

I would not choose the option with the mids and tweeters near the ceiling and the woofer on the floor. I'd prefer the mids and tweeter down closer to the woofer, with a fairly wide overlap and smooth blend between woofer and midrange. The second option with the tall mid source - something like a line array - might be a good option. You could do this with a line of drivers perhaps. But in that case, I might be also tempted to use a line of tweeters instead of a point source.

Naturally, my way of doring this is what I've done in my six π and seven π loudspeakers. In those, the woofer and midhorn have a wide overlap to smooth the upper modal region. The midhorn and tweeter are tightly coupled to provide good summing over a 90°x40° pattern. You could always scale up the midhorn if you wanted. Larger horns tend to provide acoustic loading and pattern control down to a lower frequency. The only thing to watch out for is that you don't also reduce the upper frequencies or make it too large to give good verticals. There are lots of competing priorities to balance.

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Re: Two midbass horn layouts... [message #60372 is a reply to message #59567]

Thu, 09 July 2009 22:06

Bill Wassilak
Messages: 402
Registered: May 2009

Illuminati (1st Degree)

I would go with your 2nd option. Like Wayne said " The second option with the tall mid source - something like a line array - might be a good option."

I use 8 - 6.5" drivers, operating at 100-2.3kHz in a 55" line array for p.a. for mids, the drivrs are Dayton's from Parts Express, and they run pretty much flat, what ever room I put them in.

I recommend Jim Griffen's white paper on line array's. Which can also be found on this board.