My Dual Tang Band 8x12 Tapped Horn Project - Page 3 - Home Theater Forum and Systems - HomeTheaterShack.com

Reply
 
Thread Tools
post #21 of 99 Old 01-17-10, 07:30 PM
Senior Shackster
 
Join Date: Jul 2006
Location: I ain't tellin ya!
Posts: 267
Re: My Dual Tang Band 8x12 Tapped Horn Project

Oklahoma Wolf, don't get to strung out on it.

Here is the sub from your 1st post Horn compared to the EBS from above at xmax limits 1/2 space.


There is more to it than 1W/1m output.

That said, the TB really want a huge horn. No getting around it. With the lowish BL you may want to drop compression down to 2:1.

Good luck.
soho54 is offline  
Sponsored Links
Advertisement
 
post #22 of 99 Old 01-17-10, 07:51 PM Thread Starter
Senior Shackster
Jeremy
 
Join Date: Dec 2009
Location: Eastend, SK, Canada
Posts: 333
Re: My Dual Tang Band 8x12 Tapped Horn Project

Roger that. I may raise the corner just a smidge anyway so I can go ahead and knock out that fourth panel of plywood. Or maybe fold it a bit different. Would lowering the compression ratio tweak be all that necessary? I'm kind of thinking I'd rather leave it be unless it'll end up being dangerous to the driver as is.
Oklahoma Wolf is offline  
post #23 of 99 Old 01-17-10, 08:27 PM
Senior Shackster
 
mwmkravchenko's Avatar
Mark
 
Join Date: Jul 2009
Location: Perth Ontario Canada
Posts: 580
Re: My Dual Tang Band 8x12 Tapped Horn Project

Good constructive post Jacob!

I'm just back from dropping off my kid's and I was going to post max SPL. You beat me to it

Mark

___________________________________________________________________________ ___________

Mark

Artificial intelligence is no match for natural stupidity.
mwmkravchenko is offline  
 
post #24 of 99 Old 01-17-10, 10:28 PM
Senior Shackster
 
Join Date: Jul 2006
Location: I ain't tellin ya!
Posts: 267
Re: My Dual Tang Band 8x12 Tapped Horn Project

At it's present compression level I think the driver should survive do to its shape.

2.5: 1 would be about as high as I would go, with 2:1 my safe bet. This is all just best guess work though, unless someone else has used or tested the driver out.

I always lean to the safe side. YMMV.

Last edited by soho54; 01-17-10 at 10:39 PM.
soho54 is offline  
post #25 of 99 Old 01-17-10, 10:45 PM Thread Starter
Senior Shackster
Jeremy
 
Join Date: Dec 2009
Location: Eastend, SK, Canada
Posts: 333
Re: My Dual Tang Band 8x12 Tapped Horn Project

Ok, I have a revision 6 design drawn up. Compression ratio is slightly lower at 3.29:1 - I could not get anything close to 2:1 to work well. If that's conceivably going to be a problem, let me know now... I'm fixing to stop tweaking this as soon as I get the new folding diagram done tomorrow. Corner is a little bit higher but not much.

This one is optimized for an additional segment at the end of the horn with no flare and should theoretically allow me to reduce the number of plywood sheets I need to three. Will find that out tomorrow, and tweak revision 6 as needed to make sure it fits properly with the box dimensions.

This is half space, 2.83V input.





I can get decent results with an S1 up to 300, but that's about as far as I can get it to look good. Compression ratio on that one is 2.55:1.

Just for giggles, this is the most recent Unibox sim I have for the IXL LLT for comparison. This is at the full 1kW the driver will take, but it is too much for the design. You can only put 600W into it safely. It's also before I dropped the tuning frequency to 10.75Hz.



Edit - someone posted while I was getting my post ready. Will see if I can get S1 to behave at 300

Edit 2 - nope, can't get it to cooperate. Every time I try, compression ratio starts going back up again, or the corner goes up, or something else goes south. I'm going to run with revision 6. I get the feeling I could tweak this for a year and still not be completely happy. It's my first tapped horn - doesn't need to be perfect

Last edited by Oklahoma Wolf; 01-17-10 at 11:07 PM.
Oklahoma Wolf is offline  
post #26 of 99 Old 01-18-10, 09:23 AM Thread Starter
Senior Shackster
Jeremy
 
Join Date: Dec 2009
Location: Eastend, SK, Canada
Posts: 333
Re: My Dual Tang Band 8x12 Tapped Horn Project

My problem last night was that I was thinking two dimensionally. Original design depth was 15." This is what I get at 16 inches, with the drivers moved 10cm further in. Compression ratio 3:1.





And this is at 17" deep. I might go with this one - undecided yet. Not sure I like what this does to the response and the cutlist, but it's no big deal I think. Compression ratio 2.84:1.





Here's the cut list for the 17" version. To get this to work, I had to kludge one fold baffle by making it too short and then plotting a 2.5" wide patch piece to bolt to the end of it. Might just do that for all the too long panels.

I think I'll stick to 3/4" stock, but will get cheap CDX for one of the panels. Nobody's going to see the inside folds. But maybe I can still get this down to three sheets by kludgery and then using up my leftover stuff in the storage room.



Edit - I just got three sheets of stock to work. Going back to the original 15" plan. Compression is 3.2:1 with a driver move. Enough is enough... I'm going to go crazier than normal if I keep tweaking this

Last edited by Oklahoma Wolf; 01-18-10 at 09:58 AM.
Oklahoma Wolf is offline  
post #27 of 99 Old 01-18-10, 12:41 PM
Elite Shackster
 
Ricci's Avatar
Josh
 
Join Date: May 2007
Location: Louisville, KY
Posts: 2,431
Re: My Dual Tang Band 8x12 Tapped Horn Project

Quote:
mwmkravchenko wrote: View Post

Calculating into 4 Pi is an interesting concept. Who of us listens 30 feet off the ground outside to a subwoofer 30 feet off the ground?

2 Pi is the most general free field SPL calculation.
Mark
Quote:
soho54 wrote: View Post
Ricci, I am also wondering about the free space graph request. I would assume everyone would be happy with ground plain equivalent half space sims.

This is just my opinion. Yes half space is fine. I think it most accurately reflects what type of headroom you'll see in room at the listening position too (as much as can be). IMHO unless you are placing the enclosure in a vehicle or a concrete bunker the 8th space sim and to some extent even the 1/4 space sim is highly optomistic and not likely to happen in reality especially since you'll likely be 3, 4 or even 5 m away from the sub while listening and rooms are lossy. If 8th space is to be believed I only need a couple of 8" drivers to produce more than plenty of output. It's not the case from my experience. Why wouldn't you do simulations in WINISD at a distance of 1/4m then? Using 8th space simulation a single LMS 5400 18 in a small 100L sealed enclosure as tested by Illka per CEA2010 should do in excess of 116db at 12.5hz, 2 meters away in room. It won't.

I always use 4pi space because it shows what you can expect at a bare minimum without any unknown room influence and approximates what would happen in a test comparable with Illka's or AVtalks FWTW. It does approximate 2m GP outdoors. It's easy to estimate the 1m half space or quarter space output from there.

BTW sorry about the thread high jack Jeremy. I think you are on a good track with the build and am looking forward to seeing how things play out.
Ricci is offline  
post #28 of 99 Old 01-18-10, 01:13 PM Thread Starter
Senior Shackster
Jeremy
 
Join Date: Dec 2009
Location: Eastend, SK, Canada
Posts: 333
Re: My Dual Tang Band 8x12 Tapped Horn Project

Quote:
Ricci wrote: View Post
BTW sorry about the thread high jack Jeremy. I think you are on a good track with the build and am looking forward to seeing how things play out.
No worries - I'm learning a fair bit from you as well... it's kind of hard getting back into my interest in audio after having tried to put it aside and not think about it for so many years. Slowly but surely my brain's starting to come back to me

One of the reasons I like these TB 8x12's is two of them combined have about the cone area of a fifteen, even if I still wish they had just a bit more Xmax to them. I just couldn't see Wolfhorn I making me happy, even with four of the TB 6x9's split across two cabinets (for those not familiar with my AVS thread, the drivers in question are the TB W69-1042M - you can only find them on eBay to my knowledge).

The Dayton DVC used in the Tuba HT might work in the Wolfhorn II design as well, but then I'd have no choice about making the box deeper. Another plus to the oval TB's. And the fifteen would be less tolerant of the compression ratio too.

Going back on topic, I think I'll compromise a little and increase depth to 15.5." That will allow room for bracing while still allowing for the thickness of the saw blade. I will be using some damping material around some of the folds to hopefully help with standing waves.
Oklahoma Wolf is offline  
post #29 of 99 Old 01-18-10, 05:14 PM
Senior Shackster
 
Join Date: Jul 2006
Location: I ain't tellin ya!
Posts: 267
Re: My Dual Tang Band 8x12 Tapped Horn Project

Quote:
Ricci wrote: View Post
I always use 4pi space because it shows what you can expect at a bare minimum without any unknown room influence and approximates what would happen in a test comparable with Illka's or AVtalks FWTW. It does approximate 2m GP outdoors.
I will agree that 8th space is useless and overly optimistic. It is not the correct setting for cabin gain either though. 1/4 space can be personally useful, but there is need to post graphs of it.

The thing is that an outdoor ground plain measurement is a 1/2 space measurement. GP is just a technique used to eliminate the floor bounce problem non-GP 1/2 space measurements produce with lower(sub) frequencies. 1/2 space is what you will get bare minimum in any application, unless you have no ceiling and set your subs up in the middle of the room on 10ft poles.

I can understand wanting to compare to the old sub tests, but I think it would mess more people up than help when all other programs default to 1/2sp 1m, and sensitivity is also based off the same. Pulling 6db off in your head isn't that hard for anyone who would know to do it for a 2m conversion.

If you look over at diyAudio there is another thread where a supposedly knowledgeable guy started a big who ha because he didn't get this stuff completely. He was comparing 8th space Hornresp predictions to 1/2 space sims in other programs, then measuring at 1/2sp in real life, and claiming horns aren't sensitive and HR is giving inflated sims. I am not comparing him to you, I am trying to show that most people really don't get boundary gain and the inverse distance law. Even some of the ones you would think had it worked out don't.

There was another thread where this came up, but I don't remember which one. I wanted to put this there, but... That was my side of the OT topic anyway, I will try to keep from veering off again OKW.
soho54 is offline  
post #30 of 99 Old 01-18-10, 05:26 PM Thread Starter
Senior Shackster
Jeremy
 
Join Date: Dec 2009
Location: Eastend, SK, Canada
Posts: 333
Re: My Dual Tang Band 8x12 Tapped Horn Project

No problem - your post had to go somewhere, and I'm glad it was in a place I could find it

And it gives me an excuse to post a small update - the drivers have shipped. Now to go make me a break-in test tone disc. The plan is to feed them 10Hz for 24 hours or so to let the suspensions loosen up. Planning on getting some video of that.

Another short comment - the Dayton DVC will not work in this design. I can get a tapped horn to work with it, but not this one. IIRC there's a Tang Band ten incher that will, but Solen doesn't stock it.
Oklahoma Wolf is offline  
Reply

Bookmarks

Tags
8x12 , band , dual , horn , project , tang , tapped

Quick Reply
Message:
Options

Register Now




PLEASE COMPLETE ALL REQUIRED FIELDS BELOW... THANKS!

REQUIRED FIELDS ON THIS PAGE
YOU MUST COMPLETE ALL OF THESE

Username
Password
Confirm Password
Email Address
Confirm Email Address
Random Question
Random Question #2




User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
PLEASE READ BELOW PRIOR TO ENTERING AN EMAIL ADDRESS!

ATTENTION!

YOU MUST ACTIVATE YOUR ACCOUNT!

Activation requires you reply to an email we will send you after you register... if you do not reply to this email, you will not be able to view certain areas of the forum or certain images... nor will you be able download software.

AN INVALID EMAIL ADDRESS WILL CAUSE YOUR ACCOUNT TO BE DELETED!

See our banned email list here: Banned Email List

We DO NOT respond to spamcop, boxtrapper and spamblocker emails... please add @hometheatershack DOT com to your whitelist prior to registering or you will get nowhere on your registration.


Email Address:
OR

Log-in










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



Posting Rules  
You may post new threads
You may 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 is not allowed!
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

 


For the best viewing experience please update your browser to Google Chrome