William,
I had posed a question a few days ago in this thread that you are answering with your last post, although somewhat obliquely.
What I take from your post is that the length, rate of expansion, throat size & mouth size of the horn have a direct relationship to the driver being used. If in fact that is the case, how does one go about optimizing the horn to the driver?
I've looked around quite a bit, and I haven't found anything that seems even vaguely definitive as to the relationship between a driver's parameters and the TH horn parameters that would be best suited for that driver. If you know of a place to find that information, It would be a great help.
Paul
I had posed a question a few days ago in this thread that you are answering with your last post, although somewhat obliquely.
What I take from your post is that the length, rate of expansion, throat size & mouth size of the horn have a direct relationship to the driver being used. If in fact that is the case, how does one go about optimizing the horn to the driver?
I've looked around quite a bit, and I haven't found anything that seems even vaguely definitive as to the relationship between a driver's parameters and the TH horn parameters that would be best suited for that driver. If you know of a place to find that information, It would be a great help.
Paul
In the type of work I do, I do a lot of troubleshooting. The only reasonable way that I have found, when the gestalt method doesn't work is to change one thing at a time.
If I apply the iterative approach of build, test, build... to this problem it could take quite a bit of time and sawdust to iterate through the various combinations. I was hoping there were a few constants that I could rely on such as the length of the horn, and the mouth size, as this would allow the construction of a large part of the cabinet. I would then have the throat size, and port placement to vary along with driver configurations.
In your experience are you aware of any "rules of thumb" that one can use to keep a portion of the cabinet constant while changing other things?
Paul
If I apply the iterative approach of build, test, build... to this problem it could take quite a bit of time and sawdust to iterate through the various combinations. I was hoping there were a few constants that I could rely on such as the length of the horn, and the mouth size, as this would allow the construction of a large part of the cabinet. I would then have the throat size, and port placement to vary along with driver configurations.
In your experience are you aware of any "rules of thumb" that one can use to keep a portion of the cabinet constant while changing other things?
Paul
hahaha - its really cool to see software and discussion which can handle "stuff.
in my feeble mind, speakers are designed to purpose (bandwidth & output vs bulk), drivers on hand or out of sheer madness and disregard to practical outcome.
is it ok when wanting to examine lengthening or shortening a horn with fixed width and depth to change just the length input?
how about a box with sizable cavity and very little "horn" like Fitzmaurice's omni & Yorkville's L368 - what's the simplest model for that case?
Freddy
in my feeble mind, speakers are designed to purpose (bandwidth & output vs bulk), drivers on hand or out of sheer madness and disregard to practical outcome.
is it ok when wanting to examine lengthening or shortening a horn with fixed width and depth to change just the length input?
how about a box with sizable cavity and very little "horn" like Fitzmaurice's omni & Yorkville's L368 - what's the simplest model for that case?
Freddy
hey William - when looking at tall one-fold TH like your 30Hz example using 15" drivers and inside width ~driver frame diameter, should pipe's depth generally be increased vs 17" for 12 inch driver or will it work about right keeping 17" external depth? - got B&C trx40 & 15pzb40 laying around which don't like in reflex - no punch vs Karlson and too much cone movement.
did you build any 15"TH?
Best,
Freddy
ps - still need model for mutual load case - I cna't see very well and don[t have working printer
did you build any 15"TH?
Best,
Freddy
ps - still need model for mutual load case - I cna't see very well and don[t have working printer
FWIW here's 1st attempt at 4.1M TH with 15TRX40 - mighta botched one input - seemed to like a mouth ~12" high vs 15" - width = ~1.25* William's 30Hz TH
input Z pretty high - looks like B&C running out of excursion above 32vrms or so (?)
http://img169.imageshack.us/img169/1065/15trx4041mtry1li0.gif
input Z pretty high - looks like B&C running out of excursion above 32vrms or so (?)
http://img169.imageshack.us/img169/1065/15trx4041mtry1li0.gif
I just came across this thread. I buildt some tapped horns this winter. I started with a small 8" for prototyping. Did some modelling in Hornresp. Then I have made two 30 Hz horns for 15". I did some measurements that I believe may be of interest to you. I tried an Altec 515B and a Jensen F15LL. Here are the curves:
The red is the 515B and the blue is the F15LL. The horn is the same for both drivers. The measurements are done in the mouth. Measurements at 1m are similar and between 90 and 100dB.
I also had to try the Akabak script and did a quick test this evening. I only have TS data for the 515B as my computer with all my data on crashed last week and have not gotten to the data yet. Here is the modelled results for the 515B:
I am not sure I have used the script correctly.
seh
An externally hosted image should be here but it was not working when we last tested it.
The red is the 515B and the blue is the F15LL. The horn is the same for both drivers. The measurements are done in the mouth. Measurements at 1m are similar and between 90 and 100dB.
I also had to try the Akabak script and did a quick test this evening. I only have TS data for the 515B as my computer with all my data on crashed last week and have not gotten to the data yet. Here is the modelled results for the 515B:
An externally hosted image should be here but it was not working when we last tested it.
I am not sure I have used the script correctly.
seh
hi seh - that looks very good and would expect Altec 515 to sound good as 416 was nice imo with low-tuned Karlson and boost - did not have "thick" sound which I dread.
how large is your 15" tapped horn and what are your impressions of its sound quality? most tapped horn seen so far use moderately high mass woofer.
Freddy
how large is your 15" tapped horn and what are your impressions of its sound quality? most tapped horn seen so far use moderately high mass woofer.
Freddy
Hi Freddy,
I am happy with the sound. The tapped horns are replacing some large 30Hz bass horn which did not play deeper than 40 Hz. I am playing with only horns and the tapped horns fits well. I am currently playing on two Jensen F15LL drivers. The amplifiers I am using are not optimal.
The size of the horn inside measures 66cm deep, 45 cm wide and 210cm high. The dividing "baffle"inside is approximately 23 cm from the back at the bottom and 175cm long. The horn is rear loaded with the driver facing forward. The F15LL is deep so this is why I have 23cm at the bottom.
seh
I am happy with the sound. The tapped horns are replacing some large 30Hz bass horn which did not play deeper than 40 Hz. I am playing with only horns and the tapped horns fits well. I am currently playing on two Jensen F15LL drivers. The amplifiers I am using are not optimal.
The size of the horn inside measures 66cm deep, 45 cm wide and 210cm high. The dividing "baffle"inside is approximately 23 cm from the back at the bottom and 175cm long. The horn is rear loaded with the driver facing forward. The F15LL is deep so this is why I have 23cm at the bottom.
seh
Hi Seh - that's still a managable size (especially footprint) compared to 'regular' basshorn. Is the divider split ~equal from and rear panels? Whats your TH bass amplifier, midbass horn, xover etc?
how does it sound on bowed bass and cello? Klipschorn sound ~bad- horrible - although problematic I like a karlson better on Gary Karr's Koussevitzsky cd
Freddy
how does it sound on bowed bass and cello? Klipschorn sound ~bad- horrible - although problematic I like a karlson better on Gary Karr's Koussevitzsky cd
Freddy
William,
I finally took a moment to look at Akabak. The manual is 285 pages, I feel totally inadequate.
At this point I do not even have a clue where to begin, I would love to simulate my ideas prior to making sawdust, and I felt pretty good about mastering WinISD, but this makes me want to take up crocheting.
This is where it would be good to have someone local that has worked with the tool, and could show me how to get started.
Is there a simple tutorial that can get me started? Or are you going to be in S Florida anytime soon?
Paul
I finally took a moment to look at Akabak. The manual is 285 pages, I feel totally inadequate.
At this point I do not even have a clue where to begin, I would love to simulate my ideas prior to making sawdust, and I felt pretty good about mastering WinISD, but this makes me want to take up crocheting.
This is where it would be good to have someone local that has worked with the tool, and could show me how to get started.
Is there a simple tutorial that can get me started? Or are you going to be in S Florida anytime soon?
Paul
Patrick,
After writing that post, I did just that, and it seems to work.
Now I need to understand a few things in order to modify stuff, my main confusion at present is the dimensions;
It appears to use scientific notation, but in this example;
a1 = 354e-4; |Area at throat (cm^2)
a2 = 360e-4; |Area at rear of driver (cm^2)
a3 = 1050e-4; |Area at front of driver (cm^2)
a4 = 1055e-4; |Area at mouth (cm^2)
a1 through 14 seem to range from .0354 cm^2 to 1.0550 cm^2 and these numbers don't seem reasonable.
What am I missing?
Paul
After writing that post, I did just that, and it seems to work.
Now I need to understand a few things in order to modify stuff, my main confusion at present is the dimensions;
It appears to use scientific notation, but in this example;
a1 = 354e-4; |Area at throat (cm^2)
a2 = 360e-4; |Area at rear of driver (cm^2)
a3 = 1050e-4; |Area at front of driver (cm^2)
a4 = 1055e-4; |Area at mouth (cm^2)
a1 through 14 seem to range from .0354 cm^2 to 1.0550 cm^2 and these numbers don't seem reasonable.
What am I missing?
Paul
"zero throat" is the way AJ-Horn models "BIB" type BLHwhich look like Cowan's tapped horn examples. AJ must use Parabolic to get correct result.
AJ-Horn iinput window
http://img236.imageshack.us/img236/8022/bib15cxainputhx9.gif
BIB vs conical with BM15CXA
http://img402.imageshack.us/img402/4195/bm15cxbibvscondn6.gif
AJ-Horn iinput window
http://img236.imageshack.us/img236/8022/bib15cxainputhx9.gif
BIB vs conical with BM15CXA
http://img402.imageshack.us/img402/4195/bm15cxbibvscondn6.gif