Number crunching as requested
OK ljk11
I ran the simulations for the vifa driver.
Thanks to Mr. McBean it is really quite accurate.
The efficiency is pretty close to the SDX7. The surface area is actually a little larger. So all in all after I crunched the numbers I get the following:
Not that bad! I tried simulating a midrange driver. On a reall horn it would work but as this is a very short poor excuse for a horn it requires a driver that is rather close to the original specs.
You can't get such a small box without it costing something somewhere.
After a spirited discussion last night with one of the members I have to agree with his basic premise.
You don't do high end because it is cheaper. You do it because it is unavailable from anyone else.
Mark
OK ljk11
I ran the simulations for the vifa driver.
Thanks to Mr. McBean it is really quite accurate.
The efficiency is pretty close to the SDX7. The surface area is actually a little larger. So all in all after I crunched the numbers I get the following:
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Not that bad! I tried simulating a midrange driver. On a reall horn it would work but as this is a very short poor excuse for a horn it requires a driver that is rather close to the original specs.
You can't get such a small box without it costing something somewhere.
After a spirited discussion last night with one of the members I have to agree with his basic premise.
You don't do high end because it is cheaper. You do it because it is unavailable from anyone else.
Mark
A couple more economy drivers
The following drivers are inexpensive and will give you close to the same result. If you want to do the number crunching then the input parameters have been posted:
Dayton DC160-8 6-1/2" Classic Woofer
Peerless 835004 SDS 6-1/2" Woofer 4 Ohm
These are very economical drivers. The response attained is close enough to work well. They will not get you as loud but I don't think most people at normal listening levels will require more sound pressure level.
Mark
The following drivers are inexpensive and will give you close to the same result. If you want to do the number crunching then the input parameters have been posted:
Dayton DC160-8 6-1/2" Classic Woofer
Peerless 835004 SDS 6-1/2" Woofer 4 Ohm
These are very economical drivers. The response attained is close enough to work well. They will not get you as loud but I don't think most people at normal listening levels will require more sound pressure level.
Mark
GM wrote:
This Cinemonster:
http://www.danleysoundlabs.com/tapped_horn.asp?MODEL=TH 221
I guess I spelt it wrong. This would be downright evil to work with. The Pyle drivers are the only thing even close to affordable for this level of performance. I'm guessing GM has already worked up something on this one.
The TRIO8 tapped horn is going from simulation to end product soon. I have worked out a layout and the design stage is in the works as is a dual SDX7 for home use.
Mark
This Cinemonster:
http://www.danleysoundlabs.com/tapped_horn.asp?MODEL=TH 221
I guess I spelt it wrong. This would be downright evil to work with. The Pyle drivers are the only thing even close to affordable for this level of performance. I'm guessing GM has already worked up something on this one.
The TRIO8 tapped horn is going from simulation to end product soon. I have worked out a layout and the design stage is in the works as is a dual SDX7 for home use.
Mark
Wasn't aware of this sub and at 58 ft^3 gross is considerably larger than my old 45+ ft^3 ~70 Hz horns, though about the same weight which I find rather surprising. Must be a lot of wood in them.
Yeah, I ran the numbers on the Pyle back when the specs were posted, which BTW are fairly close to P-Audio's 21". To go low with two in a TH requires a Vb similar to the CineMonster's, but the frame shown is different from these two, so apparently not either of them.
GM
Yeah, I ran the numbers on the Pyle back when the specs were posted, which BTW are fairly close to P-Audio's 21". To go low with two in a TH requires a Vb similar to the CineMonster's, but the frame shown is different from these two, so apparently not either of them.
GM
Hello GM
From the connections I have with a few gents they are all one in the same. More or less. There has been a bit of monkey business with the basket but the motor and cone + surround is pretty much the same. It's really amazing how many vendors sell basically the same driver.
My biggest question is a decently accurate Sd for the pyle 21" driver.
And my second question is where is this wonderful sim ?
I may commit it to a box or two.
Either that or I may get committed if I use them to much.
Probably 3/4" Finish birch. That much birch ply is heavy to start with. Then add the drivers and boom. Can you say Hernia that is Mr. Hernia.
Mark
From the connections I have with a few gents they are all one in the same. More or less. There has been a bit of monkey business with the basket but the motor and cone + surround is pretty much the same. It's really amazing how many vendors sell basically the same driver.
My biggest question is a decently accurate Sd for the pyle 21" driver.
And my second question is where is this wonderful sim ?
I may commit it to a box or two.
Either that or I may get committed if I use them to much.
Probably 3/4" Finish birch. That much birch ply is heavy to start with. Then add the drivers and boom. Can you say Hernia that is Mr. Hernia.
Mark
Can't say as I'm surprised considering that 21" must be a relatively real low volume product.
Solving from the published specs I get 1987.4 cm^2 which seems about right to me, but the P-Audio is listed at 'only' 1660 cm^2, so YMMV and makes me wonder just what parts might be shared.
The 58+ ft^3 is for the CineMonster, mine would be slightly bigger for two, but after seeing how close my sim's impedance matches it, I could probably shrink it enough to closely match it once stuffing is factored in. Anyway, I'll play with it a little.
Historically, TD specs 3/4 (19 mm) 13 ply Baltic Birch.
GM
Solving from the published specs I get 1987.4 cm^2 which seems about right to me, but the P-Audio is listed at 'only' 1660 cm^2, so YMMV and makes me wonder just what parts might be shared.
The 58+ ft^3 is for the CineMonster, mine would be slightly bigger for two, but after seeing how close my sim's impedance matches it, I could probably shrink it enough to closely match it once stuffing is factored in. Anyway, I'll play with it a little.
Historically, TD specs 3/4 (19 mm) 13 ply Baltic Birch.
GM
Comparing the Pyle to a B & C
I took the specs off the B&C as it is almost the same O.D.
It comes out to 1680 cm squared.
My sim is plunking along but I just started it. The depressing thing is I crunched two 15 inch drivers from CSS and they are pretty damn close to what I'm currently getting from the two 21" as the 15" have a 30mm X-max so usable volume is 790 * 3 = 2.37 liters for the SDX15. The Pyle comes out to 1680 * 1.2 = 2.016 liters Even the B&C at 15mm X-max comes out to 1680 * 1.5 = 2.52 liters But the price ratio is painful.
I wish hornresp had a provision for resistive dampening. That's really what the wall padding is doing. From what I have read of others results and the fooling around I have done it basically slows down the egress of the pressure wave a bit making it look like a longer horn than it really is. Like padding an enclosure to make it appear as a larger volume acoustically. There is always a happy medium where it adds and a point where you've gone over board and it is actually a hinderence. Some thing like cooking. To much spices and it is awful just enough and it tastes good.
Mark
I took the specs off the B&C as it is almost the same O.D.
It comes out to 1680 cm squared.
My sim is plunking along but I just started it. The depressing thing is I crunched two 15 inch drivers from CSS and they are pretty damn close to what I'm currently getting from the two 21" as the 15" have a 30mm X-max so usable volume is 790 * 3 = 2.37 liters for the SDX15. The Pyle comes out to 1680 * 1.2 = 2.016 liters Even the B&C at 15mm X-max comes out to 1680 * 1.5 = 2.52 liters But the price ratio is painful.
I wish hornresp had a provision for resistive dampening. That's really what the wall padding is doing. From what I have read of others results and the fooling around I have done it basically slows down the egress of the pressure wave a bit making it look like a longer horn than it really is. Like padding an enclosure to make it appear as a larger volume acoustically. There is always a happy medium where it adds and a point where you've gone over board and it is actually a hinderence. Some thing like cooking. To much spices and it is awful just enough and it tastes good.
Mark
Check out Bjorno's work in this thread:
http://www.diyaudio.com/forums/showthread.php?postid=1884958#post1884958
He has done some very careful thinking along the lines of equal output amplitude and box size for the same driver complement. Give credit where credit is due right?
Mark
http://www.diyaudio.com/forums/showthread.php?postid=1884958#post1884958
He has done some very careful thinking along the lines of equal output amplitude and box size for the same driver complement. Give credit where credit is due right?
Mark
Re: Comparing the Pyle to a B & C
Yeah, other than for my remark about size earlier, for horns I'd rather use several relatively small, cheap drivers that gets the job done with just a few clean watts.
Load it into MJK's software as a sectioned TL to get a pretty good idea of how it will affect it.
All the rest is my understanding and/or experience.
GM
PS - Haven't messed with shrinking it to fit DSL's dims if halved, but its impedance plot is pretty close, so once shrunk and damped it should in theory have more than passing resemblance to the CineMonster.
mwmkravchenko said:
Yeah, other than for my remark about size earlier, for horns I'd rather use several relatively small, cheap drivers that gets the job done with just a few clean watts.
Load it into MJK's software as a sectioned TL to get a pretty good idea of how it will affect it.
All the rest is my understanding and/or experience.
GM
PS - Haven't messed with shrinking it to fit DSL's dims if halved, but its impedance plot is pretty close, so once shrunk and damped it should in theory have more than passing resemblance to the CineMonster.
Attachments
Ok back from some hecktick work week
I have more exterior work nowadays than I care to. And Ottawa has just had a record month of rainfall. So when the sun is shining I have to haul out and geterdun!
Back to some info on boxes.
GM
Your design is interesting and I have played with it a bit. You are indeed a hard act to follow. It is almost optimized as is. Very close. The Danley design appears to have two horn paths in a common mouth. That is hard to model correctly in Hornresp but I have been playing a bit. In MJK software there is greater facility to work in the dampening.
Greg did I read correctly somewhere that you encouraged modeling a tapped horn as a series of T-lines?
I have yet to fully grasp the worksheets from MJK but they are worth their weight in gold. If you want to learn something or the other about horns fork over the money. They are worth every penny. My hats off to you Martin. I have done horn calculation pre computer and then with a BASIC program from Speaker Builder away back when. Things have come a long way since then. And my head hurts less from the math !
The twin 8 and SDX7 designs are in the works and will be started this weekend as I have Monday off. My kids stay with their Mom all August so I have more time to play on not so important things. July was my month with the kids. Enjoyed every minute but not so good for loudspeaker design.
The work Bjorno did was both thorough and well thought out from the perspective of use in a home. In a room there is more of a chance to have equal amplitude over the pass-band of a speaker.In a car go figure. You can get wildly different reading by moving a foot. I realize this can be so in a house to but you have to see the difference to believe it in a car.
So smaller and lower we go on one hand. Larger and louder if GM and I knock out the dual 21". I can get these drivers at a decent rate if there is any interest.
Mark
I have more exterior work nowadays than I care to. And Ottawa has just had a record month of rainfall. So when the sun is shining I have to haul out and geterdun!
Back to some info on boxes.
GM
Your design is interesting and I have played with it a bit. You are indeed a hard act to follow. It is almost optimized as is. Very close. The Danley design appears to have two horn paths in a common mouth. That is hard to model correctly in Hornresp but I have been playing a bit. In MJK software there is greater facility to work in the dampening.
Greg did I read correctly somewhere that you encouraged modeling a tapped horn as a series of T-lines?
I have yet to fully grasp the worksheets from MJK but they are worth their weight in gold. If you want to learn something or the other about horns fork over the money. They are worth every penny. My hats off to you Martin. I have done horn calculation pre computer and then with a BASIC program from Speaker Builder away back when. Things have come a long way since then. And my head hurts less from the math !
The twin 8 and SDX7 designs are in the works and will be started this weekend as I have Monday off. My kids stay with their Mom all August so I have more time to play on not so important things. July was my month with the kids. Enjoyed every minute but not so good for loudspeaker design.
The work Bjorno did was both thorough and well thought out from the perspective of use in a home. In a room there is more of a chance to have equal amplitude over the pass-band of a speaker.In a car go figure. You can get wildly different reading by moving a foot. I realize this can be so in a house to but you have to see the difference to believe it in a car.
So smaller and lower we go on one hand. Larger and louder if GM and I knock out the dual 21". I can get these drivers at a decent rate if there is any interest.
Mark
Am I missing something here?
Bjorno posted a wonderful looking design that I think he claimed had more equal amplitude response at higher sound pressure levels.
http://www.diyaudio.com/forums/showthread.php?postid=1884958#post1884958
I ran his numbers thoroughly from post #10 and this is what I get:
Now that is no where near to flat amplitude response. I have been messing around with other designs at higher power levels and it is interesting what the Hornresp program comes up with. The lower level simulations of the UNHORN were actually quite accurate. I gues it's build it and measure.
Mark
Bjorno posted a wonderful looking design that I think he claimed had more equal amplitude response at higher sound pressure levels.
http://www.diyaudio.com/forums/showthread.php?postid=1884958#post1884958
I ran his numbers thoroughly from post #10 and this is what I get:
An externally hosted image should be here but it was not working when we last tested it.
Now that is no where near to flat amplitude response. I have been messing around with other designs at higher power levels and it is interesting what the Hornresp program comes up with. The lower level simulations of the UNHORN were actually quite accurate. I gues it's build it and measure.
Mark
Re: Ok back from some hecktick work week
Thanks, it's just my interpretation of Prof. Leach's math, but until I build a TH to see how it compares to a sim there's not much point me going any further with it. How did you improve it?
With my eyesight/monitor, I can't see hardly any details of DSL's TH, so don't have a clue what you're referring to.
Encouraged? Don't recall, but did suggest it in my previous post.
Yes, they are. I've had the later horn WSs for quite awhile, but have yet to take the time to work through them. They appear much more flexible than his earlier ones that are a snap to use with the trade-off being very limited flare factor choices.
?? What did you have in mind and where do I fit in? I mean I didn't post it as a potential for profit venture for anyone.
GM
mwmkravchenko said:
Thanks, it's just my interpretation of Prof. Leach's math, but until I build a TH to see how it compares to a sim there's not much point me going any further with it. How did you improve it?
With my eyesight/monitor, I can't see hardly any details of DSL's TH, so don't have a clue what you're referring to.
Encouraged? Don't recall, but did suggest it in my previous post.
Yes, they are. I've had the later horn WSs for quite awhile, but have yet to take the time to work through them. They appear much more flexible than his earlier ones that are a snap to use with the trade-off being very limited flare factor choices.
?? What did you have in mind and where do I fit in? I mean I didn't post it as a potential for profit venture for anyone.
GM
Tweeked bandwidth and a bit on the volume. I'm stuck on volume because two horn mouths in tandem reinforce one another by about 3 db. But I have no easy way simulate two horns in close proximity. So improved is in the eye of the beholder.
Profit is a scarce commodity in this forum. I sold one box with almost 8 000 hits. And no one has given a comment on whether they have built anything. I posted the plans as plainly as I can to make your own. This is a show and tell with measurements and a critique by outside parties. I have posted a commercial offering that is actually $30 above cost. No bites so I guess I'm fishing in the wrong pond. So recoup on drivers is all that I have gained. If a large dual 21" box comes out of it great. As for profit don't hold your breath.
But that won't stop me from posting designs. And I hope it will not stop you either GM.
If you want to discuss something off forum drop me a line as I cannot send you an e-mail.
The post is here:http://www.diyaudio.com/forums/attachment.php?s=&postid=1885165&stamp=1248192855
Note the input power the loading into a 2 pi space and the output level at 108 db with 36 watts input. I'm not trying to criticize Bjorno's work. I'm just trying to understand what is going on here.
Mark
P.S. Sad drawing is bare bones cinemonster mouth.
Attachments
Best pic I could make of Cinemonster
http://www.filefactory.com/file/ahheec5/n/CINEMONSTER_pdf
Here you go GM. A PDF that you can enlarge even more should you care to.
Mark
http://www.filefactory.com/file/ahheec5/n/CINEMONSTER_pdf
Here you go GM. A PDF that you can enlarge even more should you care to.
Mark
Re: Am I missing something here?
Hi Mark,
This post may help to explain why 🙂.
http://www.diyaudio.com/forums/showthread.php?postid=1894241#post1894241
Kind regards,
David
mwmkravchenko said:
Hi Mark,
This post may help to explain why 🙂.
http://www.diyaudio.com/forums/showthread.php?postid=1894241#post1894241
Kind regards,
David
Hi all,
Agree with David. Posting Constant Power plots is very confusing if having limited knowledge on how to interpret what those in fact are representing.
Even showing only Constant Voltage plots without the HR main input screen is as well IMO bad, leaving the reader to guess if this is reliable or not.
This can be seen in the threads supported with posted HR plots where in the texts the buzzword 'SPL' occurs almost as a 'Mantra'
and the only parameter discussed besides huge thermal input Wattages.
Here follow two pictures 1(2)-2(2) that I hope will show that my posted SPL plots are quite achievable and well supported/ backed up with pictures from other HR tools.
For instance I always show displacements plots defining on what BW I'm targeting and that is safe SPL wise.
b
1(2)
Agree with David. Posting Constant Power plots is very confusing if having limited knowledge on how to interpret what those in fact are representing.
Even showing only Constant Voltage plots without the HR main input screen is as well IMO bad, leaving the reader to guess if this is reliable or not.
This can be seen in the threads supported with posted HR plots where in the texts the buzzword 'SPL' occurs almost as a 'Mantra'
and the only parameter discussed besides huge thermal input Wattages.
Here follow two pictures 1(2)-2(2) that I hope will show that my posted SPL plots are quite achievable and well supported/ backed up with pictures from other HR tools.
For instance I always show displacements plots defining on what BW I'm targeting and that is safe SPL wise.
b
1(2)
Attachments
Thankyou
Thanks to David McBean and to Bjorno.
Embarasing as it is to say I did not read the whole manual. The explanation is very simple and the results are exactly as explained.
Mystery solved.
Mark
Thanks to David McBean and to Bjorno.
Embarasing as it is to say I did not read the whole manual. The explanation is very simple and the results are exactly as explained.
Mystery solved.
Mark
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