Post by: Antone Atmarama Bajor on May 27, 2006, 02:51:40 PM
A question arose when looking at the Lab v3 Vs Lab "v2".
What are the implications of having a Hyperbolic Sine Horn (expansion rate greater than 1). That apears to be how the Lab v3 was built.
I am asuming that the LAB subs where designed with a Size Factor of 4?
How flexible are the mouth dimensions for a size factor 2 Horn?
Would optimal be either a circle of appropriate radius/ square that is the sqr(area). I'm wondering this since the Labs only have an expansion on one axis.
Could a rectangular mouth that expands on one axis (and meets all of the area requirments be as usefull in a size factor of 2 horn?
When I exported the data from the horn flare, it gave me grayed out symetrical dimensions. If I just keep the height constant what can I expect good performance If I just accept the single axis expansion (say if I stack them 2 High?)
Any how here is one of the horns I am modeling.
Its a segmented aproximation of a Hyperbolic expansion rate of .55.
Using exponential or conical sections in the model don't seem to make much difference.
Antone-
Post by: Antone Atmarama Bajor on May 27, 2006, 02:53:43 PM
Post by: Antone Atmarama Bajor on May 27, 2006, 03:41:45 PM
Post by: peter.golde on May 27, 2006, 04:09:20 PM
Post by: Jeff Robinson on May 28, 2006, 02:31:51 AM
I've been shooting for 100Hz with less than 1 meter of throat length.
So far this is the best I've modelled in Hornresp.
4 Pi space load but note the T/S parameters are for dual EVM10M driver source.
Please excuse the cobbled together graphics.
I think for ground stacked subs 1/2 space is right,
but for midbass in mobile PA you ought to allow for use of singles in free air.
I think Dwg86 models ok for 3 or 2/cluster and even 1 doesn't look bad considering the 1 meter throat length constraint.
The problem will be the tight spacing from the phase plug to the boundary wall.
My thanks to Bill Geiger for suggesting the dual driver format as a means of shortening the horn.
Jeff Robinson
PS; The most compact graphics file format I've found is png, I'll see your 200KB and raise you 16KB.
Post by: Antone Atmarama Bajor on May 28, 2006, 04:51:43 AM
The rest of the time they will be on top of BT7's.
I have yet to find anything that models well in Free space unless I want to build a horn of Size Factor 1.
Antone-
Post by: Antone Atmarama Bajor on May 28, 2006, 03:05:13 PM
This should perform in free space like 1 in half-space.
Yet another hyperbolic approximation 122 cm long flare .55 80Hz.
Antone-
Post by: Antone Atmarama Bajor on May 28, 2006, 03:12:41 PM
Question:
If you have to consider cone volume when solving for Throat chamber. Why does Hornresp try to override it when you are trying to use its hypex calculator?
Wouldn't that mean you have to stick a mass between the cone and throat to take up the cone area?
Antone-
Post by: Bogdan Popescu on May 30, 2006, 02:47:07 AM
I am considering it for my midbas.
http://www.ddshorns.com/catalog.php?page=DVB15NPro
Bogdan
Post by: Antone Atmarama Bajor on May 30, 2006, 04:50:19 AM
I would think this would work only for Low Mid not Mid Bass. You can't cheat physics.
Antone
Post by: Bogdan Popescu on June 01, 2006, 04:37:04 AM
I would love to hear from DDS. I write them a mail and never got any answer...
Bogdan
Post by: Antone Atmarama Bajor on June 01, 2006, 12:58:12 PM
Antone-
Post by: Antone Atmarama Bajor on June 01, 2006, 04:41:34 PM
Building it into a Straight horn seems impractical.
What are the pitfalls of doing a W bin/Vs Snail.
Whats the critical Wavelength relation ship of the folds to keep in respect to HF performance.
A lot of W bins I have seen are sort of like two halves of a snail horn where the flairs meet in the center instead of expanding outwards. That seems wrong to me since this doesn't create a complimentary horn mouth but maybe it doesn't matter?
Would it be better to do a Wbin "reentry horn" (Like a megaphone?) How do either effect polar up in the High range????
If I don't fold the Horn the Length without the driver/compression chamber attached is 4'.
Any help on the topic would be greatly appreciated.
If I did a Phase plug in the throat to improve polar I'm guessing that I need to keep the throat area the same as it would be across the flair as if there was no plug there?
Or do I need to pay for this information as no one seems to have any comments?
Thanks.
Antone-
Post by: peter.golde on June 01, 2006, 08:14:00 PM
Post by: Antone Atmarama Bajor on June 02, 2006, 02:07:30 PM
The only problem Is I already own the JBL 15's I would like to use them the DR300 Is designed to use 12's.
I have no idea where the Xover frequencies are but, smoothness of the bends is not the only thing that will determine HF performance. Wavelength relationships of bends will also have and effect as well as throat area. The vertical expansion of the DR 300 only occurs in the first several inches then stays constant. I imagine that will cause a HF problem as well.
I know I wouldn't have to mount horns in it but. Having both horns radiation patterns overlapping like that is not very good. They may sum coherently in their low end but will interact badly as frequency increases.
I'm still wondering about having the flairs expanding to the center making a non complimentary horn mouth.
Its a cool design for sure, but Unless someone wants to swap my 2225's for some of the Eminence Definimax 12's I'll have to seek out another design.
Antone-
Post by: Tracy Sherwood on June 03, 2006, 12:25:15 AM
The DVB-15N horn flare only offers pattern control to 190hz and will provide loading to the specified 80hz only in a properly designed ported enclosure. There is a compresion factor introduced to the cone and not all 15" speakers are up to the task.
The specifications may seem confusing in that regard, they were published by the original founder of the company Robert Rice and may need to be re-evaluated/clarified. DDS recently relocated into a larger facility and is phasing out direct sales to contractors in general due to pressure from OEM clients.
-Tracy Sherwood, Primary, DDS LLC.
Post by: Antone Atmarama Bajor on June 03, 2006, 03:56:16 PM
It sorta reminds me of the old JBL 15 half horn half relex idea.
Thats to bad that you are stopping selling dirrect I can't find anyone that carries the CFD-1-100 or 1-110.
Antone-
Post by: Bogdan Popescu on June 07, 2006, 03:39:50 AM
Bogdan
Post by: Too Tall (Curtis H. List) on June 14, 2006, 02:41:43 PM
| Antone Atmarama Bajor wrote on Sat, 27 May 2006 14:53 |
Here is predicted response of 2 half space with 1 in gray. |
First thing that bothers me is the lack of any high end at all. You would need the biggest high frequency horn DDS makes to reach down to where it rolls off.
I know nothing of horn modeling so perhaps this can be taken cars of somehow???
For an 80Hz horn I have direct experience using straight horns, both made by Community.
My first PA used a Community FRC/B with a single 15” woofer.
I was talking it over with AL Limberg and best we can guess is the horn mouth was 42” wide by 32” high by 36” deep.
This put out 80Hz, but not one cycle lower. When I pushed it running full range below 1200Hz I had to use double gaskets on the 15” to keep the surround from striking the horn throat.
From 80Hz up it was one of the most efficient, punchy and just plain nice to listen to speakers I have ever used. With a sub under and a 2” compression driver over very few 3-way designs could touch for volume without distortion. It lost favor because it was not arrable and just plain too big, thought it was very light in weight compared to what it put out.
Next is the Community “Boxer” flare.
The original design was a flair that held dual 15” (or dual 18”). The flare was 28.5” wide by 48” high by 36” deep. This slipped into a box that was the same width, but 60” high and 45” deep. You put the flare in the middle giving you a 6” by 28” port above and below. The rest of the box volume left over from the flare was used for a ported solution. There were curved ribs on the sides, top and bottom for bracing. Some really big panels to brace.
Al built a box only 48” and made a very small sealed volume the drivers shared.
This measured dead flat from 80Hz to 1200Hz and sounded wonderful with LAB subs below and M-4 midrange above. For lighter gigs he ran it all the way down to 40Hz with EQ, but you had to be careful. (One of the advantages of a sealed vs ported design.)
If I had to make a serious mid-bass this is it. Just curve the sides of the flare with some bending plywood or carbon fiber if you are fancy.
A smaller mouth or less depth is a real compromise, not that we don’t do it every day…
Post by: Phil Pope on June 14, 2006, 03:34:53 PM
Phil
Post by: Stephen Kramer on April 16, 2007, 09:40:21 PM
http://www.users.uswest.net/~ddshorns/dvb15n.htm
sorry to bump an old post, but I came across this on a search:
| Quote: |
Hello Antone, The DVB-15N horn flare only offers pattern control to 190hz and will provide loading to the specified 80hz only in a properly designed ported enclosure. There is a compresion factor introduced to the cone and not all 15" speakers are up to the task. The specifications may seem confusing in that regard, they were published by the original founder of the company Robert Rice and may need to be re-evaluated/clarified. DDS recently relocated into a larger facility and is phasing out direct sales to contractors in general due to pressure from OEM clients. -Tracy Sherwood, Primary, DDS LLC. |
Any info on the cab specs and drivers to achieve these specs would be of great help.
Thanks,
Steve