FlipC said:
Somehow it sounds like you are better at it, as I have no clew about what to do
Very long ago I asked about whether it would be possible to mount a big woofer in the mouth of a very big quaterwave
I had no clew what so ever, but a few people picked it up and started to discuss the Danley patent...so yes, it would really please me to see this Tapped-ACE get somewhere
It may not be different from the ordinare tapped, but offsetting the "V" a bit, like its done in the original quaterwave, may be doing something, maybe
Besides the "compressed" pushpull is inspired by JLH, and I think of his design as a really genious way of making a pushpull at its best, dissplacement doubles and both drivers seem like they are very evenly loaded, tied together
Only this one is really straight forward and less complicated, yet transistion to throath is even smoother still
But I would never have thought of it, havent I seen the JLH
Actually Im known to just toss the wood together making horns from what I feel is right, surely not the proper way, but seems to work ok as I have build horns from I was around 14, but could most like be much better with todays software
Reading a few pages a day, I'm almost all the way through but haven't noticed the following issue addressed yet, or maybe I skimmed right over it.
A tapped horn will have dramatically different frequency response depending on where you put it according to the following models. For example, the first 2 graphs here are the 18sound driver mentioned several times. The first graph is relatively flat (could be flatter still) all the way up past 200 hz, but the second one is not even close. The only difference is the top one is .5 pi, the second is 2 pi.
For me, this is the probably the final straw, that extra octave or so at the top end is just too tricky. Even if you pick the right driver and model a nice flat bandwidth, it would seem that it's all shot if you put it the wrong spot in the room. The upside of that is if the bandwidth is not needed, it looks like the box can be a whole lot smaller. The following model is the same maw15 from the last model a few posts ago, but now it's only 175L (105L smaller than last time), at the cost of about 1 db and a few hz bandwidth. I'm almost confident enough about design considerations and compromises to pick a design and build, but the drivers are still in the mail.
MAW15 tapped horn, 175L, 800W
A tapped horn will have dramatically different frequency response depending on where you put it according to the following models. For example, the first 2 graphs here are the 18sound driver mentioned several times. The first graph is relatively flat (could be flatter still) all the way up past 200 hz, but the second one is not even close. The only difference is the top one is .5 pi, the second is 2 pi.
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.
For me, this is the probably the final straw, that extra octave or so at the top end is just too tricky. Even if you pick the right driver and model a nice flat bandwidth, it would seem that it's all shot if you put it the wrong spot in the room. The upside of that is if the bandwidth is not needed, it looks like the box can be a whole lot smaller. The following model is the same maw15 from the last model a few posts ago, but now it's only 175L (105L smaller than last time), at the cost of about 1 db and a few hz bandwidth. I'm almost confident enough about design considerations and compromises to pick a design and build, but the drivers are still in the mail.
MAW15 tapped horn, 175L, 800W
An externally hosted image should be here but it was not working when we last tested it.
This would be the case with any subwoofer.
But why so many in the HT/hiFi world take room measurements and either build to suit or EQ accordingly.
tinitus
Sorry but even though I ahve thought about it I am unsure how you would go about trying to model your layout in HR. I can only assume someone could do it in Akabak but I am just learning that.
The mother would have to be behind the driver
on the left hand side. You would have a compression chamber in between that is ported to the path so what effectively becomes S1. Also in a TH the rear radiation becomes in phase due to the travel it makes back and forth. But since the compression chamber makes it so you have 3 entry points instead of 2 Im clueless.
Someone mock this up !
But why so many in the HT/hiFi world take room measurements and either build to suit or EQ accordingly.
tinitus
Sorry but even though I ahve thought about it I am unsure how you would go about trying to model your layout in HR. I can only assume someone could do it in Akabak but I am just learning that.
The mother would have to be behind the driver
on the left hand side. You would have a compression chamber in between that is ported to the path so what effectively becomes S1. Also in a TH the rear radiation becomes in phase due to the travel it makes back and forth. But since the compression chamber makes it so you have 3 entry points instead of 2 Im clueless.
Someone mock this up !
"A sealed or ported box does not exhibit dramatically different modelled frequency response based on changing only .5 pi and 2 pi like that."
Says who?
http://www.jblpro.com/catalog/support/getfile.aspx?doctype=3&docid=837
http://www.jblpro.com/catalog/support/getfile.aspx?doctype=3&docid=626
Says who?
http://www.jblpro.com/catalog/support/getfile.aspx?doctype=3&docid=837
http://www.jblpro.com/catalog/support/getfile.aspx?doctype=3&docid=626
That was me, I said it.
Ok, all joking aside, you are both right I guess but missing my point. Frequency response does change for any box in these different environments, but see the enclosed example to see that although frequency response shifts a bit in this closed box when moved from .5 to 2 pi, it stays quite flat. In other words, the frequency response does not suddenly become excessively bumpy just because you moved the box, the whole bandwidth is shifted and slightly different but still very usable. In the tapped horn example posted previously the response becomes unusable (imo) just from moving it out of the corner.
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.
Why I model 1/2 space.
Plus if you noticed I mentioned that mine do not have the perceived spike at that 200 Hz area that HR predicted. Though yours starts at 100 Hz. I would play around and flatten it out a bit more. But I assume that this isn't something you were going to build but rather an example of the statement.
Plus if you noticed I mentioned that mine do not have the perceived spike at that 200 Hz area that HR predicted. Though yours starts at 100 Hz. I would play around and flatten it out a bit more. But I assume that this isn't something you were going to build but rather an example of the statement.
FlipC said:
Its strange, I know
But actually I would think that the 2 split lines ought to be considered as one, and the output from both present summed output...at least I cant see it any other way
So why have they offset the "V" loadline...means it supposed to do something...but what
Could it be that they wanted to spread the unavoidable and unwanted internal ressonances, instead of having two completely alike ressonances summed...I actually think I have heard something like that before
If its not significant one could just do it completely symmetrical, and do with the possible advantage of a mutual compression chamber fore the two drivers, have the optimal pushpull, and still doubled displacement
My only reason for looking at this ACE design is to have the brilliant JLH pushpull chamber, and still being simple and easy to build
Or else the even simpler standard tapped would be preferred
Thanks fore attention
Ok, so you design for flat response in halfspace. Move it into a corner and it won't be anywhere close to flat anymore. Then what?
I realize there will be differences between modelled and measured performance, and WC and TD are always saying you need to build to confirm, and then build again (and again, and again and again...) until you get the response you want. I'm just trying to gain a basic level of understanding of how this works before spending a fortune on wood and thousands of hours on things that can be sorted out with modelling before advancing to the build and measure and repeat process.
Hi, it sounds to me like if there is some doubt about how to model a 2-driver TH correctly
please excuse me if Im wrong on that
But to me it seem like 2 drivers mounted closely together, seems to me like it should simply be modelled as ONE bigger oval driver, with fixpoint in the middle between the two
With the drivers moved apart, with one of the two drivers further up the line, then surely its a whole different situation
Just a thought
oh maybe it should have been over at "double driver tapped horn"...weel it actually seems that Cowan agree
please excuse me if Im wrong on that
But to me it seem like 2 drivers mounted closely together, seems to me like it should simply be modelled as ONE bigger oval driver, with fixpoint in the middle between the two
With the drivers moved apart, with one of the two drivers further up the line, then surely its a whole different situation
Just a thought
oh
maybe it should have been over at "double driver tapped horn"...weel it actually seems that Cowan agreejust a guy
They actually perform flatter. You get the 10db gain on the low end
but only 5 on the spikes in the upper. Since I don't have any spikes over 6 db it works out.
And as a suggestion.
Use OSB for testing. 6 bucks or less per sheet.
tinitus
I had a thought of modeling it as 2 different cabs and overlaying them and adding 2.5db. I have been contemplating a dual 12" for 50 Hz and lower. I would assume this or the Spud style will be the only way to make it a manageable size.
They actually perform flatter. You get the 10db gain on the low end
but only 5 on the spikes in the upper. Since I don't have any spikes over 6 db it works out.
And as a suggestion.
Use OSB for testing. 6 bucks or less per sheet.
tinitus
I had a thought of modeling it as 2 different cabs and overlaying them and adding 2.5db. I have been contemplating a dual 12" for 50 Hz and lower. I would assume this or the Spud style will be the only way to make it a manageable size.
FlipC said:
Thanks, I would love that
btw,
As I said at other thread
In think that the TappedHorn, in any form, is the ultimate design, where pushpull seems to be at its absolute best, due to the mouth presenting a true genuine summed output, right...its actually main reason fore my interest, so please go easy on SPL and low end output, and focus on smoothness
I don't know what this means. Pictures explain everything better. Look at the ones I posted. The upper harmonic spikes don't change much in amplitude (level) in .5 or 2 pi space, but everything below those spikes changes in level quite a bit when you change the radiating environment. The response has a knee right in the middle of it's bandwidth that goes up or down depending on placement. Can't you see that?
Fabricated another 18" driver/horn combination with Home Depot's 1-1/8" sub-flooring plywood. My bud and I also fabricated a 10" driver/horn combination as well. His horn uses Home Depot's 3/4" eleven ply birch plywood. Imagine that, eleven ply plywood for less than $40.00 a sheet. That's half of what it used to cost.
It took us about eight hours to build the pair...
I tested them in my large great-room. I made the mistake of not turning off the parametric EQ--10 db boost at 20hz feeding a Euro-power 2500 sub-amp. The bass wave is so large and powerful that it literally travels through floors and walls. As I would soon find out, it gains lower octave depth as it travels through the house.
My wife was so angry, I though she could have slapped me into next week. I know that bass can travel through wall, but didn't expect it to travel through floor levels. Needless to say, I discovered another 50 ways to say "I'm sorry."
Like I said in another post, the bass these horns produce is somewhat invisible. You don't necessarily hear it, instead, it feels like a giant hand twisting the house. If a wall hanging isn't screwed, or glued down, it rattles like a jalopy on a washboard road--fun and scary at the same time.
I love the horn, but may have to give it to a friend if I value my marriage (just joking--I think). Tomorrow, I'm going to give it another try, but without the parametric EQ. If I can't tone that first octave down, my wife won't be able to enjoy movies, or music on the system. It would be rather unfair of me to put her through that.
The 10" version went to my bud's house. He and his wife are young, late twenties. She loves the project. In all fairness to my sweetie, the volume difference between their first listen and mine was around 25db. Toccata Fugue in D minor sounded like I was standing in a cathedral when I fired mine up. Wow... the horn hits those low organ notes with no strain and seems capable of a much stronger challenge. I should get a copy of the 1812 overture. Ha. Better play it when the wife's not around...
Back to the 10" version: Interestingly enough, it can hold it's own against the 18" horn much better than I would have imagined. It tops out sooner, of course, but it had no problem keeping up with a pair of 18" drivers in a 15 c.f. bass-reflex enclosure. In fact, it went lower, and did it with more authority than the reflex enclosure. A 10" driver edging out a pair of 18s? Jeeze, guess a small driver will deliver the goods! The horn is roughly 12"X12"X90". Just a tot compared to the 18" driver/horn combination.
Well, this post was intended to inspire some of you folks to grab your skill-saws and saw-guides and make some sawdust. I didn't use a table-saw once. The only tools I used were the skill-saw, an 8 foot saw guide (to keep the cuts ruler straight), a framing square, pencil, tape-measure, jig-saw (cutting the speaker holes), and screw-guns (cordless impact for the screws, cordless drill for the counter-sink). A pair of saw-horses will keep your knees and back happy. Yes, a belt sander is a wonderful invention as well, but it isn't absolutely necessary in order to fabricate a test-mule. BTW, good-luck, and remember to use plenty of glue.
It took us about eight hours to build the pair...
I tested them in my large great-room. I made the mistake of not turning off the parametric EQ--10 db boost at 20hz feeding a Euro-power 2500 sub-amp. The bass wave is so large and powerful that it literally travels through floors and walls. As I would soon find out, it gains lower octave depth as it travels through the house.
My wife was so angry, I though she could have slapped me into next week. I know that bass can travel through wall, but didn't expect it to travel through floor levels. Needless to say, I discovered another 50 ways to say "I'm sorry."
Like I said in another post, the bass these horns produce is somewhat invisible. You don't necessarily hear it, instead, it feels like a giant hand twisting the house. If a wall hanging isn't screwed, or glued down, it rattles like a jalopy on a washboard road--fun and scary at the same time.
I love the horn, but may have to give it to a friend if I value my marriage (just joking--I think). Tomorrow, I'm going to give it another try, but without the parametric EQ. If I can't tone that first octave down, my wife won't be able to enjoy movies, or music on the system. It would be rather unfair of me to put her through that.
The 10" version went to my bud's house. He and his wife are young, late twenties. She loves the project. In all fairness to my sweetie, the volume difference between their first listen and mine was around 25db. Toccata Fugue in D minor sounded like I was standing in a cathedral when I fired mine up. Wow... the horn hits those low organ notes with no strain and seems capable of a much stronger challenge. I should get a copy of the 1812 overture. Ha. Better play it when the wife's not around...
Back to the 10" version: Interestingly enough, it can hold it's own against the 18" horn much better than I would have imagined. It tops out sooner, of course, but it had no problem keeping up with a pair of 18" drivers in a 15 c.f. bass-reflex enclosure. In fact, it went lower, and did it with more authority than the reflex enclosure. A 10" driver edging out a pair of 18s? Jeeze, guess a small driver will deliver the goods! The horn is roughly 12"X12"X90". Just a tot compared to the 18" driver/horn combination.
Well, this post was intended to inspire some of you folks to grab your skill-saws and saw-guides and make some sawdust. I didn't use a table-saw once. The only tools I used were the skill-saw, an 8 foot saw guide (to keep the cuts ruler straight), a framing square, pencil, tape-measure, jig-saw (cutting the speaker holes), and screw-guns (cordless impact for the screws, cordless drill for the counter-sink). A pair of saw-horses will keep your knees and back happy. Yes, a belt sander is a wonderful invention as well, but it isn't absolutely necessary in order to fabricate a test-mule. BTW, good-luck, and remember to use plenty of glue.
Tinitus
My interest isn't in HT/Hifi
So that is why I come from the SPL angle. I figured out the TH Mini. Least really close. I built a pair of those to go along with a set of 12" 2 ways pole mounted on top for house parties.
Now I want to figure out the TH 115 and also how to model dual driver TH's correctly. So I am starting with Akabak.
It is all just a desire to know how to make a TH outperform a typical horn. Plus if I could come up with something I could build that can preform 20-50 hz in the 135 DB range that is easily movable.
just a guy
TO answer your question- yes.
I believe we are saying the exact same thing there. I just don't see a problem with it. Though I wouldn't personal build that box. Though the MAW15 tapped horn, 175L, 800 doesn't look to bad.
What space is the chart in?
And I assume these are just models. Not something you are thinking of building?
carpenter
How about some HR or Akabak info on your build?
Also, what brand of plywood did you purchase at Home Depot? In in AL and all they have are freaking pine for Georgia Pacific. The OAK is good but costly.
My interest isn't in HT/Hifi
So that is why I come from the SPL angle. I figured out the TH Mini. Least really close. I built a pair of those to go along with a set of 12" 2 ways pole mounted on top for house parties.
Now I want to figure out the TH 115 and also how to model dual driver TH's correctly. So I am starting with Akabak.
It is all just a desire to know how to make a TH outperform a typical horn. Plus if I could come up with something I could build that can preform 20-50 hz in the 135 DB range that is easily movable.
just a guy
TO answer your question- yes.
I believe we are saying the exact same thing there. I just don't see a problem with it. Though I wouldn't personal build that box. Though the MAW15 tapped horn, 175L, 800 doesn't look to bad.
What space is the chart in?
And I assume these are just models. Not something you are thinking of building?
carpenter
How about some HR or Akabak info on your build?
Also, what brand of plywood did you purchase at Home Depot? In in AL and all they have are freaking pine for Georgia Pacific. The OAK is good but costly.
All my graphs are corner loaded unless specifically stated otherwise. The two that were not corner loaded were only posted for comparison to see the effect of .5 vs 2 pi. So the maw 15 graph you speak of was modelled as a corner load.
The graphs based on the 18sound were only there because they show the "knee" quite clearly, I am not going to buy that driver, or build for it. The maw15 on the other hand is a driver I already own and if I find a tapped horn design better than the one it is currently in (regular tl) I will build it.
