Single sheet TH challenge

Hi Don,

I definitely found those post helpful, thanks.

I set PrimoPDF as my default printer, and print from Acad into PrimoPDF. That gives me a .pdf file that the can be posted, as a bonus the file is a lot smaller. PrimoPDF still has a free download version.

Regards,
 
Jbell and Oliver, I just had a thought for the SS15. I've made a small correction suggestion for the SS15 to make it more close to the ideal HornResp layout and maybe it will help in the low end efficiency... This correction makes the total length just a little shorter by just a couple of inches in favour to the overall path-expansion. As far I can see it is possible within the 1 sheet challenge. Any comments?
 

Attachments

  • TB_02.jpg
    TB_02.jpg
    80.3 KB · Views: 562
Last edited:
Hi DJIM - I've always been a little "anal" about folding Tapped Horns. Soon after Jim did his SS15, I spent an hour "fixing" his design, but it was a waste
of time. Short of changing the box volume or the folding method, nothing I did was going to add 1dB or lower the response 1Hz.

Here is a GIF of my version ... I can email you a .DWG
 

Attachments

  • SmallBell.gif
    SmallBell.gif
    5.5 KB · Views: 554
Hi Djim,

I have tried that general approach on paper, but it looks like everytime I reduce the L12 distance, and the S1 area, the upper frequency response smoothens out. So that's the direction I would suggest at this point. I haven't said much about it, as the SS15 is just about as good, and as simple as you can get under the general limitations of the single board challenge (or so).

I'll attach a typical example, that is a lot larger, but would improve on the output of the SS15 (on paper):

Regards,
 

Attachments

  • 2011_Mar01_mod_5_Try2.pdf
    23.1 KB · Views: 207
Hi DJIM - I've always been a little "anal" about folding Tapped Horns. Soon after Jim did his SS15, I spent an hour "fixing" his design, but it was a waste
of time. Short of changing the box volume or the folding method, nothing I did was going to add 1dB or lower the response 1Hz.

Here is a GIF of my version ... I can email you a .DWG
Hey Don, I know lowering the response is not possible as total volume and path length don’t increase. In this case I just added the ‘wasted’ space/volume at the beginning of the TH. But probably you are right the added volume is to small to show (significant) changes. Maybe it’s just that I don’t like the idea of a non used space when it can be added to the system.
 
I'll attach my drawings in pdf format, it was done late at night, let me know if you find any big errors..
tb46; I am looking at the drawings now, but have most of the paper work at work?
There seems to be no real improvement over the original SS15, and there is a larger dip @ 144Hz than in the SS15.
Did you sim it in hornresp? Can you post the setting screen and SPL graph? When I simed it it looked better.
Thanks for all your work. Andy
 
Last edited:
It's entertaining envisioning your minds warping inside out trying to improve this -- which is exactly why I started this thread in the first place !!
(being serious here, I'm grateful for the help)

Oliver, now that's a stadium horn !! big and bold.
 
Last edited:
Hi Djim,

I have tried that general approach on paper, but it looks like everytime I reduce the L12 distance, and the S1 area, the upper frequency response smoothens out. So that's the direction I would suggest at this point. I haven't said much about it, as the SS15 is just about as good, and as simple as you can get under the general limitations of the single board challenge (or so).

I'll attach a typical example, that is a lot larger, but would improve on the output of the SS15 (on paper):

Regards,
Hi Oliver, my suggestion fits within the one sheet challenge so that’s not the problem, I think. The increase of volume at the blue points 10 and 11 in your drawing can have an effect on the lower response. Your ‘rolled out’ pathway isn’t showing everything as the 'dip' between 10 and 11 is going deeper then your dashed line suggests (make an extra point in between and you’ll see it). So that’s why I was thinking hmmm interesting... you don’t need extra wood and the extra space is already there... Maybe not significant but it can’t hurt.
 
OK Oliver; I am not seeing any glaring mistakes in your convershoin of my drawing.
I used some different reference points though. I used 3.5" for S1, 90 degrees from the speaker plate. I had S4 straight down from S2 on the other side of the speaker plate at 90 degrees off the bottom. Is this why my sim looked better?
I did not use two lines into the corners. I only made one at a 45 degrees into the corner on my hand drawings. Is yours going to be more accurate?
Why is the purple line in the unfolded map of my box bent between S3 and ref line #8? If we bend it at S3 and shorten ref line #10 for the bottom deflector the end of the horn will look a lot better.
Andy
 
Pyros, the ideal line you can see in Oliver's post # 559. In the second PDF file this ideal line is purple. The only problem in his representation is within the dashed line (the actual outlines of the cabinet) as it doesn't have enough reference points in corners so it doesn't show the extended volume very good. In this way each corner is represented by four reference points but non of them represents the actual corner.
 
Last edited:
Pyros, the ideal line you can see in Oliver's post # 559. In the second PDF file this ideal line is purple. The only problem in his representation is within the dashed line (the actual outlines of the cabinet) as it doesn't have enough reference points in corners so it doesn't show the extended volume very good. In this way each corner is represented by four reference points but non of them represents the actual corner.
Ok but why is it bent after S3 in my box and at S3 in Jim's box?
 
Because it runs exactly trough the centre of reference line 8. In corners this is not exactly in the centre but around 0.7. This numbre 0.7 stands for the corner correction and is the average value for air molecule density in the corner. These points set out the path lenght of the horn. (I hope I use the correct words but otherwise somebody will correct me)
 
Last edited:
It's entertaining envisioning your minds warping inside out trying to improve this -- which is exactly why I started this thread in
the first place !! QUOTE]

Jim, you're just mean!!! I've spent hours trying to "better" your SS15 and the best I can do is lower the frequency 2Hz at a cost of 2dB. That's not
better, that's just a trade-off. Anders used a B&C driver to get a few cycles lower bottom end, but it's not as flat and it has a dip at 160. Since it's not
a "Neo" it weighs 20# more. Changing to the Eminence 3015LF removes the dip, but raises his bottom end.

Anders THAM15 expanded to 20"x23"x29" (outside), and using the 3015LF, and only one sheet of ply, is the best I can do!

The question is ... Do I have enough faith to build it !!!
 
Last edited:
It's entertaining envisioning your minds warping inside out trying to improve this -- which is exactly why I started this thread in
the first place !! QUOTE]

Jim, you're just mean!!! I've spent hours trying to "better" your SS15 and the best I can do is lower the frequency 2Hz at a cost of 2dB. That's not
better, that's just a trade-off. Anders used a B&C driver to get a few cycles lower bottom end, but it's not as flat and it has a dip at 160. Since it's not
a "Neo" it weighs 20# more. Changing to the Eminence 3015LF removes the dip, but raises his bottom end.

Anders THAM15 expanded to 20"x23"x29" (outside), and using the 3015LF, and only one sheet of ply, is the best I can do!

The question is ... Do I have enough faith to build it !!!

I'd never be mean to you don, or any of the others that have been so gracious to me... ;)

I also don't want to embarrass myself and admit how many hours I spent coming up with the ss15 design, or how many hours I've spent since trying to make it better.... That's why I know the torture that a person goes through trying.... Kinda warps your head inside out after awhile.
 
Because it runs exactly trough the centre of reference line 8. In corners this is not exactly in the centre but around 0.7. This numbre 0.7 stands for the corner correction and is the average value for air molecule density in the corner. These points set out the path lenght of the horn. (I hope I use the correct words but otherwise somebody will correct me)
OK Djim; I under stand what you are saying but that does not answer my question.
The bend in the purple line for my box ended up between S3 and ref line #8, thats not a corner, its the straight part in the back of the box. It should be bent at S3 like in the drawing of Jim's box. Did the progam bend it thare or did Oliver bend it thare?

If you draw a straight line from the top of S3 to ref line #11 and one from #11 to the end, the hole thing looks better. That bend should be at S3 and another one at ref line #11.
Andy
 
Last edited:
That's why I know the torture that a person goes through trying.... Kinda warps your head inside out after awhile.

Yeah, driving all the way to Germany to find out about stupid flutes... Calling Italians with strange accents over and over again just to find out some silly details about the relation ship between Xmax, Xlim and BL force... Spending hours at the engineering department of a Dutch gas company for gas masses and behaviour in bends... and that all besides :headbash: about this 'silly' SS15 concept and other JBell 'funny' findings.

Of course... for the good cause... I suppose... I hope ;)

Cheers Don
 
Post #571....

Hi Y'all,

You guys are quick.

Djim: I'm not going to touch the subject of corner reflectors, or whatever somebody wants to call it. Screamerusa reported his empirical results in the furybox thread, jbell added his practical experiences, and after studying the general area of discussion (over a long time period, front horns, back-loaded horn fullranges) I know less than I did when I started.

4pyros: I looked at the Hornresp files for the SS15 and your modified version again, and found that the difference was mainly from slight changes in the way the original was done, and from the fact that I had not entered values for Vtc/Atc/Ap1/Lpt in the original. I redid the original using soho54's corner method, and added the same front chamber (right or wrong) in both models. They now are quite similar, with your modified version being slightly better in the 144Hz dip area. You'll have to enter the data into Hornresp to see the lines clearly. You can reduce the dips in that area by setting S1 to .01.

As to the purple line in the flare drawing (Post #559), it's just an attempt at showing the average of the respective tapers, kind of a general sanity check for the location of the Hornresp inputs (in other words: disregard if it gives you a problem). To get this any better you will have to draw exactly what was build (which only the builder can do, as there are too many gaps in the dimensions), and use AkAbak.

jbell: I have the feeling you started with a much bigger version, and pared it down until you got the the point of no return. You certainly kept us busy. Nice work. :)

Regards,
 

Attachments

  • Comp_all_small.jpg
    Comp_all_small.jpg
    68 KB · Views: 512