Home Theater Forum and Systems banner

61 - 80 of 166 Posts

·
Registered
Joined
·
373 Posts
Kevin, if there is a chance you'd be interested in me folding up either of these two, let me know. A tapped horn may be able to dig better to 15Hz, and that's why lilmike is here...I am not as good at tapped design as I am with front-loaded designs...


JSS
How about a 'fold along with me' session for those of us that have never done this? :devil:

I have 0 design expertise, but I'm pretty good with DIY and have played enough with REW to be able to measure reasonably well. I also have the perfect 1pi space: a concrete construction apartment and the perfect corner to put one of these. 300-400 liters will leave me enough room for proper corner loading.

I would love to be able to fold up one of these. Now that I have some models to aim for, I will keep plugging away to see how you get from where I am starting to where you guys are, but I don't know if I can do that in a reasonable amount of time.

Or, to put it another way, I don't have all the toys, but I really, really wanna play too! :bigsmile:
 

·
Registered
Joined
·
373 Posts
For giggles, and to encourage others at the beginning of the learning curve, here is my first kick at the can, tapped horn:




The first try is grey. The first is just over 400 liters with a large mouth (1500 cm^2) the second increases s1 slightly but has a significantly smaller mouth (980 cm^2). That takes it down to 337 liters.

I don't think its going to reach 15Hz so I need to increase path length I guess.
 

·
Registered
Joined
·
1,026 Posts
A version with a 20Hz corner would make sense too. There are some people that insist on LF corners and others wanting the extra output that a 20Hz corner would bring.

I'm not limiting you guys in any way for the contest. You can choose your box size, corner and bandwidth with complete freedom. Also it matters not what type of horn you use. The only basis for judging the design is size, bandwidth, and output. Of course the practicality of construction is important too.

The reason for this is two-fold. First... it is fun to get everyone involved. Often people come at problems from different directions so collaboration breeds innovation. Second, I want something people can copy so that I can sell more drivers.

Once we come to a design consensus I'll build and measure one. I just don't have time to build a dozen designs. Also... the Shiva-X2 is probably the best candidate for horns. I know people are asking about the Tempest & Maelstroms but they are the wrong drivers for the application. Trust me... even without running simulation I can tell you that the enclosure sizes would be unrealistic.

Kevin Haskins
Exodus Audio
 

·
Registered
Joined
·
95 Posts
For giggles, and to encourage others at the beginning of the learning curve, here is my first kick at the can, tapped horn:




The first try is grey. The first is just over 400 liters with a large mouth (1500 cm^2) the second increases s1 slightly but has a significantly smaller mouth (980 cm^2). That takes it down to 337 liters.

I don't think its going to reach 15Hz so I need to increase path length I guess.
You're on the right track, you can use a longer mouth segment to kill that 60 Hz dip too.

Don't know if you have seen these over at AVS, they might help:

Simple Offset Driver HornResp Tutorial

Simple Tapped Horn Tutorial using Hornresp

Hey - waitaminute - wasn't this some sort of design contest???:duh:

Here I am helping my competition.....
 

·
Registered
Joined
·
17 Posts
"give us the napkin drawing next. ;-)"

kevin, here is a napkin drawing. again, not a tapped horn, but a formidable one.

i haven't worked out all the measurements/angles/etc., but something like this should replicate the sim more or less.

question: what compression ratio is the max for the shiva driver?

 

Attachments

·
Registered
Joined
·
1,026 Posts
You're on the right track, you can use a longer throat segment to kill that 60 Hz dip too.

Don't know if you have seen these over at AVS, they might help:

Simple Offset Driver HornResp Tutorial

Simple Tapped Horn Tutorial using Hornresp

Hey - waitaminute - wasn't this some sort of design contest???:duh:

Here I am helping my competition.....
I'll make it worth your while. ;-) I'll reward those who contribute the most and I exercise the right to do so based upon my own metrics. :T

We could also design a driver but I'd rather start with the Shiva first. Doing a production run of drivers cost money.

Kevin Haskins
Exodus Audio
 

·
Registered
Joined
·
1,026 Posts
kevin, here is a napkin drawing. again, not a tapped horn, but a formidable one.

question: what compression ratio is the max for the shiva driver?
As I said, it doesn't matter if it is tapped or not. Only the results matter. In terms of the compression ratio the answer is "I don't know". I didn't design it around a horn and it wasn't part of the design constraint. I don't think you are going to see a huge difference among drivers of the same size/format though in terms of what is acceptable for that compression ratio. I'd need to build the horn and destructively test a couple to see where the limits are.

You are only going to see those ratios under full bore/stroke so lets not get excited about 4:1 at this point.

Kevin Haskins
Exodus Audio
 

·
Registered
Joined
·
95 Posts
As I said, it doesn't matter if it is tapped or not. Only the results matter. In terms of the compression ratio the answer is "I don't know". I didn't design it around a horn and it wasn't part of the design constraint. I don't think you are going to see a huge difference among drivers of the same size/format though in terms of what is acceptable for that compression ratio. I'd need to build the horn and destructively test a couple to see where the limits are.

You are only going to see those ratios under full bore/stroke so lets not get excited about 4:1 at this point.

Kevin Haskins
Exodus Audio
Wow - 4:1?!? Destructive testing?!? When can I start!:devil:
 

·
Registered
Joined
·
95 Posts
"give us the napkin drawing next. ;-)"

kevin, here is a napkin drawing. again, not a tapped horn, but a formidable one.

i haven't worked out all the measurements/angles/etc., but something like this should replicate the sim more or less.

question: what compression ratio is the max for the shiva driver?

That is also a fold pattern I considered for the tapped horn - just remove the back of the rear chamber.
 

·
Registered
Joined
·
17 Posts
"As I said, it doesn't matter if it is tapped or not. Only the results matter."

oh...cool. i must have missed that part. i was feeling bad because i thought i might be spamming your thread with unrelated content.

well, in any case, my design is open source; i'd like to see some folks best it.
 

·
Registered
Joined
·
17 Posts
i feel like i am operating in parallel universes here. should i copy all my avs posts on this topic here or is everybody also following along over at avs?
 

·
Registered
Joined
·
76 Posts
Kevin,

Do the external dimensions have to be under 10 cu ft? That's only 283 liters...gonna be kinda tough to get a 15Hz horn in that...I can mess w/ the 20Hz horn some, though...

JSS
 

·
Registered
Joined
·
1,026 Posts
Kevin,

Do the external dimensions have to be under 10 cu ft? That's only 283 liters...gonna be kinda tough to get a 15Hz horn in that...I can mess w/ the 20Hz horn some, though...

JSS
No... the size is not fixed. Play around with it and submit your favorite. You could even do a tall one designed to fit in the corner.

Kevin Haskins
Exodus Audio
 

·
Registered
Joined
·
76 Posts
For a front loaded 15Hz horn, I need around 600L to get good output (over 90dB 2.83V, 2pi). The 20Hz horn gets the same output (but less extension) with 1/2 the size....

Or you could do a PA style horn (30Hz tune), same size as 20Hz horn (approx 260L), but with 120+dB on tap at Xmax at 30Hz, 2Pi space...the 20Hz horn is Xmax limited to 112dB at 20Hz in 2pi space, and the 15Hz horn at just over 110dB at 15Hz.....pick where you want to get off the train....

Choices, choices....

Which would you rather I work up (if any)?


JSS
 

·
Registered
Joined
·
1,026 Posts
For a front loaded 15Hz horn, I need around 600L to get good output (over 90dB 2.83V, 2pi). The 20Hz horn gets the same output (but less extension) with 1/2 the size....

Or you could do a PA style horn (30Hz tune), same size as 20Hz horn (approx 260L), but with 120+dB on tap at Xmax at 30Hz, 2Pi space...the 20Hz horn is Xmax limited to 112dB at 20Hz in 2pi space, and the 15Hz horn at just over 110dB at 15Hz.....pick where you want to get off the train....

Choices, choices....

Which would you rather I work up (if any)?


JSS
For a front loaded horn I think 20Hz cut-off is reasonable. The box size is certainly much more in the range of what I'd like to see.


We are going to have to do some Anarchy horns next.

Kevin Haskins
Exodus Audio
 

·
Registered
Joined
·
76 Posts
I'll work up the 20Hz front loaded horn, and make it the subject of the folding tutorial I promised everyone at AVS. Should be complete tomorrow. I'm gonna draw up 1/2" ply (12mm) for panels and reflectors, and 1/4" ply for bracing.

Quick fold tells me that this one will be around 12.5 cu ft. first folding gave me 33"x33"x20". To get under 10 cuft, you need to start with a 225-230L model...with 1/2" building material.

JSS
 
61 - 80 of 166 Posts
Top