Wolfhorn SDX Design Finished - Page 2 - AVS Forum
Forum Jump: 
Reply
 
Thread Tools
post #31 of 343 Old 09-09-2010, 09:17 PM - Thread Starter
AVS Special Member
 
Oklahoma Wolf's Avatar
 
Join Date: Nov 2006
Location: Eastend, SK, Canada
Posts: 1,742
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
Liked: 26
Interesting idea, but the problem there is that any horn with a 16Hz corner that can put out that kind of SPL is going to wind up being rather deep, even at 90" tall. The one I already built is 74" long, and still ended up being 42" deep.

The double SDX one should end up being a lot more friendly to this kind of thing in terms of width, but I don't know if it'll get you the output you want unless I start increasing the horn flare and the size along with it. It might do it as is in room, but I don't know what the room is like. And this will still end up being deep.

It's a challenge, for sure.
Oklahoma Wolf is offline  
Sponsored Links
Advertisement
 
post #32 of 343 Old 09-09-2010, 09:40 PM
AVS Special Member
 
soho54's Avatar
 
Join Date: Sep 2005
Posts: 3,329
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Liked: 17
Nearly flat to 15Hz, with real output, and inwall is out.

Mid/upper-20s in four stud bays, maybe.
soho54 is offline  
post #33 of 343 Old 09-10-2010, 01:13 PM - Thread Starter
AVS Special Member
 
Oklahoma Wolf's Avatar
 
Join Date: Nov 2006
Location: Eastend, SK, Canada
Posts: 1,742
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
Liked: 26
After giving things a lot of thought, I decided that I just can't do it... the 483L version is just not what I want from this project. I feel it's just pushing things too far toward small size. In fact, there's some temptation to let it get even a little bigger than this revision.

So, here's revision 3. Basically, all I did was take version 1 and tweak it for a parabolic flare until I was happy. The throat and mouth are both smaller, but the design is at 521 liters and probably going to stay there unless someone spots a bug I missed.

Below is the half space SPL graph at 300 watts. This takes the woofers just a hair over Xmax at about 19.3mm at 21Hz according to the sim, but that won't be a problem. The TB horn's woofers in reality take more effort to hit Xmax than Hornresp said they would. The SDX's won't even be stressed at this level.



The 300W quarter space graph shows this thing already playing above the 120dB level above 16Hz. This shouldn't be hard to achieve in room. Especially my room, where the TB horn is already hitting 120dB peaks at listening position. This one will be much more capable than that horn.

 

whsdxr3.txt 0.4130859375k . file
Attached Files
File Type: txt whsdxr3.txt (423 Bytes, 1 views)
Oklahoma Wolf is offline  
post #34 of 343 Old 09-11-2010, 08:20 PM
Newbie
 
tb46's Avatar
 
Join Date: Oct 2009
Posts: 4
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Hi Oklahoma Wolf,

I've been modelling the CSS SDX10 for a while, and am happy that somebody with building experience is taking this one on in a tapped horn.

As to the Thiele/Small parameter, the Le is listed as 1.42mH (I have noticed, that the SDX10 likes about 2_to_5mH/0.10_to_0.25_Ohm in series, and it strongly affects the frequency response, as a minor point two of these in series give at least 10 Ohms nominal impedance.

Nice work, hope you'll get to build it.

Regards,
tb46 is offline  
post #35 of 343 Old 09-11-2010, 09:42 PM - Thread Starter
AVS Special Member
 
Oklahoma Wolf's Avatar
 
Join Date: Nov 2006
Location: Eastend, SK, Canada
Posts: 1,742
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
Liked: 26
Oh, it's getting built... I just don't quite know when yet. A lot depends on money and weather. I hope to have the woofers by January... after that it'll be down to how fast mother nature can get the temperature over 10 degrees Celsius and the snow melted.
Oklahoma Wolf is offline  
post #36 of 343 Old 09-13-2010, 07:42 PM - Thread Starter
AVS Special Member
 
Oklahoma Wolf's Avatar
 
Join Date: Nov 2006
Location: Eastend, SK, Canada
Posts: 1,742
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
Liked: 26
Got a preliminary fold done this evening - it turned out to be too short so I'll have to work on that before I share the drawing.

Sketchup wasn't nice to me at first, but I prevailed. The result was a double fold sort of like the last one I built, only with the horn mouth in a different place. The final size of the design had I accepted the result would have been about 33" x 79" x 13.5" - a bit more low profile than my existing horn. But there is a significant length error that raises the corner to 18Hz, so the final product will turn out to be longer than 79." I can go to 84" in my room, and after that I have to find another folding scheme. Will report back when I have time to work on this some more and get the horn to the proper length when folded.

Edit - why not share anyway:



This is the basic shape I got out of it. The mouth is still boarded over, but it's at the bottom left corner. Woofers go on either side of that faint black line on that second horizontal panel down from the top.
Oklahoma Wolf is offline  
post #37 of 343 Old 09-13-2010, 10:11 PM
AVS Special Member
 
lilmike's Avatar
 
Join Date: Dec 2009
Location: Pacific Northwest
Posts: 2,165
Mentioned: 0 Post(s)
Tagged: 1 Thread(s)
Quoted: 3 Post(s)
Liked: 77
Hmmm, look familiar?



Hope your fold is more accurate than mine was...
lilmike is offline  
post #38 of 343 Old 09-14-2010, 06:24 AM - Thread Starter
AVS Special Member
 
Oklahoma Wolf's Avatar
 
Join Date: Nov 2006
Location: Eastend, SK, Canada
Posts: 1,742
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
Liked: 26
Heh - that does ring a bell. I actually have a completely different fold I want to try as well before I try to redo this one. It may result in the box being not quite so long and a bit wider. With my luck, it'll probably make things too complicated and still turn out too long.

Edit - refolded my first attempt to correct length errors. Box is now 84" x 36" x 13.5." Hornresp says the corner is 17Hz due to path length still coming up 19cm short. That's... acceptable. I'll give it another attempt though to try and correct some step errors.
Oklahoma Wolf is offline  
post #39 of 343 Old 09-14-2010, 03:49 PM - Thread Starter
AVS Special Member
 
Oklahoma Wolf's Avatar
 
Join Date: Nov 2006
Location: Eastend, SK, Canada
Posts: 1,742
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
Liked: 26
Got my alternate fold idea done - here's the result:



As currently modeled, it is 7' long and 44" wide. There is a big length error in this one too - it's almost a meter too long. As a result it moves the corner down to 14.5Hz at a significant SPL reduction. On this one I folded it into a seven foot package just to see if the plan would work... accuracy could come later I thought.

Honestly, I think I like this idea better than my original folding plan. All I have to do is get that extra meter off the length.

Edit - had a better idea. This brings the corner even lower to 14Hz. Will probably use this idea and just fix the length to get back to 16Hz.



You can see where I used the measuring tape to be sure the first woofer would mount properly.
Oklahoma Wolf is offline  
post #40 of 343 Old 09-14-2010, 08:32 PM
AVS Special Member
 
lilmike's Avatar
 
Join Date: Dec 2009
Location: Pacific Northwest
Posts: 2,165
Mentioned: 0 Post(s)
Tagged: 1 Thread(s)
Quoted: 3 Post(s)
Liked: 77
Hmmm, look familiar???



Let me know how it works - you'll probably get it built before me....
lilmike is offline  
post #41 of 343 Old 09-14-2010, 09:02 PM
AVS Special Member
 
soho54's Avatar
 
Join Date: Sep 2005
Posts: 3,329
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Liked: 17
Try something more involved.


This is the ELS212 tapped horn.
soho54 is offline  
post #42 of 343 Old 09-14-2010, 09:08 PM - Thread Starter
AVS Special Member
 
Oklahoma Wolf's Avatar
 
Join Date: Nov 2006
Location: Eastend, SK, Canada
Posts: 1,742
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
Liked: 26
Quote:
Originally Posted by soho54 View Post
Try something more involved.
Yikes... that one may be over my head a bit

This evening's effort may have produced the final folding diagram. I'm not unhappy with this. 78" x 43" x 13.5." Corner appears to be right at 15Hz. Horn turned out a little long again, but not nearly as bad. Attached is the Hornresp sim for the following fold diagram. Not sure it's entirely accurate, but it should be close.



300 watts in, excursion at about 21mm, half space:



Edit - hold the phone, I am unhappy with the phase response. I might tweak that baffle for driver one yet and forget about mounting it magnet down.

 

whsdxr3c.txt 0.408203125k . file
Attached Files
File Type: txt whsdxr3c.txt (418 Bytes, 0 views)
Oklahoma Wolf is offline  
post #43 of 343 Old 09-15-2010, 09:43 PM - Thread Starter
AVS Special Member
 
Oklahoma Wolf's Avatar
 
Join Date: Nov 2006
Location: Eastend, SK, Canada
Posts: 1,742
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
Liked: 26
The OCD in me just couldn't leave things alone. After thinking about it for a while, I just had to not only fix up the phase mess on the last revision, but eliminate all path length errors as well.

As a result - this is it. This is what's getting built. Revision 4 of the folding diagram shows a path length error of a whopping three centimeters. That's just over an inch that this one is short by. That does not need to be ironed out unless your name is Adrian Monk.

The final box will be 75" x 43" x 13.5." Length and width will be an inch longer than the TB horn, while the depth will be 4" less. This should pretty well fit the space I have ready for it. Dimensions will be smaller with 15mm wood, but I don't plan on using it. If desired, I'll cook up another fold diagram with 15mm.

Once I get closer to building day, I'll start up a build thread and share the fold diagram with dimensions added for anyone wishing to try this one too. Meantime, I have the final Hornresp simulation file attached - this is more or less what the box as drawn will actually do. I think I got pretty close to my original plan.



SPL, half space, 300W:

 

whsdxr3d.txt 0.4072265625k . file
Attached Files
File Type: txt whsdxr3d.txt (417 Bytes, 1 views)
Oklahoma Wolf is offline  
post #44 of 343 Old 09-16-2010, 06:20 AM
Advanced Member
 
Starkiller4299's Avatar
 
Join Date: Jan 2007
Location: SW MI
Posts: 526
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 11
Looks good, OW! That's pretty darn thin for a sub; should be pretty easy if someone wanted to hide that behind a couch....or perfect for a riser. I'm jealous of your potential output!

Sigh....those dimensions are really close to my subwoofer 'cubbyhole'...I've got these annoying built-ins that restrict the width of my potential subs to 30", and go out 14". I need to learn to fold just so I can try and squeeze other people's designs in. I'm also getting closer and closer to just taking a drywall knife to the cieling in the corner and throwing an IB in the attic.

We love overkill. -- gperkins1973
My fuse box is my HPF. -- kryptonitewhite

2x18 Ficar IB3 Infinite Baffle Manifold Install
Starkiller4299 is offline  
post #45 of 343 Old 09-16-2010, 07:14 AM - Thread Starter
AVS Special Member
 
Oklahoma Wolf's Avatar
 
Join Date: Nov 2006
Location: Eastend, SK, Canada
Posts: 1,742
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
Liked: 26
Thanks - I can't wait to build it

I checked my first folding idea, being the taller and narrower one - it still comes in at 7" too wide. Still, there's nothing wrong with a good IB - that's what I'd be doing if I weren't living in a basement.
Oklahoma Wolf is offline  
post #46 of 343 Old 09-29-2010, 08:57 PM
tg3
Member
 
tg3's Avatar
 
Join Date: Jul 2005
Location: Seattle - Broadview
Posts: 68
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
Originally Posted by Oklahoma Wolf View Post


I'm confused. Does Hornresp allow you calculate the result of two drivers at different locations? I thought 'TH - 2S' meant the drivers where side by side but electrically in series.
tg3 is offline  
post #47 of 343 Old 09-29-2010, 09:09 PM
AVS Special Member
 
lilmike's Avatar
 
Join Date: Dec 2009
Location: Pacific Northwest
Posts: 2,165
Mentioned: 0 Post(s)
Tagged: 1 Thread(s)
Quoted: 3 Post(s)
Liked: 77
The drivers are well within a 1/4 wavelength at the frequencies we're working with. At 20 Hz, a single wavelength is on the order of 17 meters, so a quarter of that is 4.25 meters.

As designed, these drivers will nearly be touching. They'll effectively be a point source until the distance between their acoustic centers is over 1/4 of a wavelength. For easy math - let's say the drivers are 30 cm center to center. 30 cm X 4 = 120 cm or 1.2 M, which is the wavelength of 286 Hz, well outside our band of interest.

So - in a nutshell, it won't matter at all so long as the drivers receive equal power and are driven in phase.
lilmike is offline  
post #48 of 343 Old 09-29-2010, 10:19 PM
AVS Addicted Member
 
LTD02's Avatar
 
Join Date: Oct 2003
Posts: 15,975
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 135 Post(s)
Liked: 854
lurking...no comments at this point...looking good. good discussion too.

Listen. It's All Good.
LTD02 is offline  
post #49 of 343 Old 09-29-2010, 11:27 PM
tg3
Member
 
tg3's Avatar
 
Join Date: Jul 2005
Location: Seattle - Broadview
Posts: 68
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
Originally Posted by lilmike View Post

The drivers are well within a 1/4 wavelength at the frequencies we're working with. At 20 Hz, a single wavelength is on the order of 17 meters, so a quarter of that is 4.25 meters.

As designed, these drivers will nearly be touching. They'll effectively be a point source until the distance between their acoustic centers is over 1/4 of a wavelength. For easy math - let's say the drivers are 30 cm center to center. 30 cm X 4 = 120 cm or 1.2 M, which is the wavelength of 286 Hz, well outside our band of interest.

So - in a nutshell, it won't matter at all so long as the drivers receive equal power and are driven in phase.

As a test, I recalculated the parameters by adding 30 cm (the center offset of two drivers close together) to L12 and L34, and subracting 60 from L34. Sure enough, the results were almost identical.

However, when I run the sim with only one driver (TH 1), the results are very different (not as smooth). Why is that?
LL
tg3 is offline  
post #50 of 343 Old 09-30-2010, 12:31 AM
AVS Special Member
 
lilmike's Avatar
 
Join Date: Dec 2009
Location: Pacific Northwest
Posts: 2,165
Mentioned: 0 Post(s)
Tagged: 1 Thread(s)
Quoted: 3 Post(s)
Liked: 77
Quote:
Originally Posted by tg3 View Post

As a test, I recalculated the parameters by adding 30 cm (the center offset of two drivers close together) to L12 and L34, and subracting 60 from L34. Sure enough, the results were almost identical.

However, when I run the sim with only one driver (TH 1), the results are very different (not as smooth). Why is that?

The driver needs to be loaded by the horn - you've got one driver in a horn sized for two, so it is severely underdamped.
lilmike is offline  
post #51 of 343 Old 09-30-2010, 08:19 AM
tg3
Member
 
tg3's Avatar
 
Join Date: Jul 2005
Location: Seattle - Broadview
Posts: 68
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
Originally Posted by lilmike View Post

The driver needs to be loaded by the horn - you've got one driver in a horn sized for two, so it is severely underdamped.

Got it. And how can you tell when a driver is properly damped (aside from the FR)? Surely the Sd/S2 compression ratio is important.

Many thanks!
tg3 is offline  
post #52 of 343 Old 09-30-2010, 10:15 AM - Thread Starter
AVS Special Member
 
Oklahoma Wolf's Avatar
 
Join Date: Nov 2006
Location: Eastend, SK, Canada
Posts: 1,742
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
Liked: 26
I just go by the FR. The compression ratio is important, though... that's why I went with the SDX woofers instead of the TC Epic 10. They both model equally well, but the TC wants a higher (but not unreasonably so) compression ratio.

Well, that and the fact that I can get the SDX's easier and cheaper.
Oklahoma Wolf is offline  
post #53 of 343 Old 09-30-2010, 11:20 AM
AVS Special Member
 
lilmike's Avatar
 
Join Date: Dec 2009
Location: Pacific Northwest
Posts: 2,165
Mentioned: 0 Post(s)
Tagged: 1 Thread(s)
Quoted: 3 Post(s)
Liked: 77
Quote:
Originally Posted by tg3 View Post


Got it. And how can you tell when a driver is properly damped (aside from the FR)? Surely the Sd/S2 compression ratio is important.

Many thanks!

In addition to compression ratio and frequency response, I look at the impulse response. The cleaner the impulse, the better the match between the horn and the woofer, all else being equal, and grossly oversimplified.
lilmike is offline  
post #54 of 343 Old 09-30-2010, 02:27 PM
AVS Addicted Member
 
LTD02's Avatar
 
Join Date: Oct 2003
Posts: 15,975
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 135 Post(s)
Liked: 854
ha, i was experimenting with a mockup for penn for a horn and arrived at the exact same fold. different dimensions, but same design.

this design definitely has simplicity going for it.

lilmike i wonder how important the impulse response is as a practical matter. i've listened to the impulse response of some really good pro audio drivers that sound almost like a chirp, while others such as the tht sound more like a "whoomp" with lots of after resonances. in practice though, the tht is generally reported to be a very clean sounding device.

oklahoma, it is looking good from over here.

when you say, "I just go by the FR." what specifically are you looking for/at?

Listen. It's All Good.
LTD02 is offline  
post #55 of 343 Old 09-30-2010, 02:45 PM
AVS Special Member
 
lilmike's Avatar
 
Join Date: Dec 2009
Location: Pacific Northwest
Posts: 2,165
Mentioned: 0 Post(s)
Tagged: 1 Thread(s)
Quoted: 3 Post(s)
Liked: 77
I'm posting mobile today, a bit of a lull in the work going on onsite.

I said grossly oversimplified .

There is a lot more than I fully understand, but a good design can eliminate a lot of the resonances, leading to a much more controlled impulse with minimal ringing.

This leads to better reproduction of the input signal, because less garbage is introduced as a result of the cabinet. To be fair, consider the band of interest, which removes a lot of the hash. Akabak can do this, soho54 showed us this a while back. Hornresp kind of can, with the spectrum option.

Anyhow, having made cabinets with bad to worse impulse responses, as well as good ones, I can say most assuredly that I prefer the sound of the cabinets with cleaner impulse responses.
lilmike is offline  
post #56 of 343 Old 09-30-2010, 02:46 PM
AVS Special Member
 
soho54's Avatar
 
Join Date: Sep 2005
Posts: 3,329
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Liked: 17
Quote:
Originally Posted by LTD02 View Post

i wonder how important the impulse response is as a practical matter. i've listened to the impulse response of some really good pro audio drivers that sound almost like a chirp, while others such as the tht sound more like a "whoomp" with lots of after resonances. in practice though, the tht is generally reported to be a very clean sounding device.

The IR is hard for most to look at, and glean anything from. HR's more so as it doesn't band limit it. The trick is to remember the large wavelengths involved with sub frequencies, and the large time gaps they would have. This is why the Spectrogram option is so nice. It allows a better presentation for people not hip to squiggly lines. Funkiness far above the passband just doesn't really matter.

The lower and flatter the FR the more whoomp that is present. The upper rolloff of the sub/driver also shapes this. If the sub is on it's way out in the 100s there isn't going to be a lot of chirp there compared to a sub that has a driver which could meet a tweeter.
soho54 is offline  
post #57 of 343 Old 09-30-2010, 03:21 PM - Thread Starter
AVS Special Member
 
Oklahoma Wolf's Avatar
 
Join Date: Nov 2006
Location: Eastend, SK, Canada
Posts: 1,742
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
Liked: 26
Quote:
Originally Posted by LTD02 View Post

when you say, "I just go by the FR." what specifically are you looking for/at?

Same thing I look for in the ladies - good looking curves

Really, what I like to see is a mostly even slope inside the intended bandwidth with maybe a small hump in the middle. That first harmonic spike (about 62Hz in my latest SPL screenshot) I usually mentally suppress a little bit to coincide a little better with reality. I also like to see a smooth set of ever decreasing dips and peaks above the bandwidth (I call it the boing-boing-boing effect - I know, I'm a loon)... this is how I know when I'm starting to get close to something that will look decent in the impulse response and phase screens.

I would say about 85% of my Hornresp modeling is done first making the FR graph look good in full, half, and quarter space; 10% checking the schematic for size; and then 5% checking the other factors to see if I got something halfway decent.
Oklahoma Wolf is offline  
post #58 of 343 Old 09-30-2010, 04:08 PM
AVS Addicted Member
 
LTD02's Avatar
 
Join Date: Oct 2003
Posts: 15,975
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 135 Post(s)
Liked: 854
interesting comments guys. thanks.

Listen. It's All Good.
LTD02 is offline  
post #59 of 343 Old 09-30-2010, 04:50 PM
AVS Special Member
 
BeerParty's Avatar
 
Join Date: Jun 2008
Location: New Hampshire, USA
Posts: 1,073
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 17
Quote:
Originally Posted by Oklahoma Wolf View Post

I call it the boing-boing-boing effect

You guys are going to have to cut down on the high tech terminology, you are losing us amateurs with all this techno-speak.

Chris

"It hurts to admit when you make mistakes - but when they are big enough, the pain only lasts a second."
--Despair, Inc. "Regret"

My AviaTrix TM Build
BeerParty is offline  
post #60 of 343 Old 09-30-2010, 05:07 PM - Thread Starter
AVS Special Member
 
Oklahoma Wolf's Avatar
 
Join Date: Nov 2006
Location: Eastend, SK, Canada
Posts: 1,742
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
Liked: 26
Quote:
Originally Posted by BeerParty View Post

You guys are going to have to cut down on the high tech terminology, you are losing us amateurs with all this techno-speak.

Go ahead - ask me how I came up with "vomit factor," or how capable a tapped horn is of making the listener lose his lunch after some bad pizza

My Tang Band horn gets a rating of 4/10 on that scale. I'm hoping for a solid 6 or 7 from this one... not that I plan on eating bad pizza again.
Oklahoma Wolf is offline  
Reply DIY Speakers and Subs

User Tag List

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page


Forum Jump: 

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off