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TRIO12 Horn Designs - Big Boy Or Little Boy?

  • Big Boy - 16 cu. ft.

    Votes: 7 29.2%
  • Little Boy - 9.5 cu. ft.

    Votes: 17 70.8%
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Discussion Starter · #1 ·
Hello folks.

I'm working on two different horn designs that will be barn burners and lease breakers. I started working on them in June so this is not a me to Danley thread. These two offerings are legitimate front loaded horns. Not tapped horns. They both when loaded into a corner have response that will be just under 100db/watt. They will both be using one TRIO12. Here is the difference. The big boy is here:



Little boy is here:



The astute among you will notice my definition of little and big has a bit of a twisted sense of humor to it. Once folded into a real box they are 16 cubic feet and 9.5 cubic feet.

I know am I crazy. If you have to ask then it isn't obvious! Here is why I'm so crazy. Here is the maximum SPL for each box.



BIG BOY



LITTLE BOY

The ripples in the response generally clear out into the room wash. So don't pay to much attention to them. Both boxes are long enough that if you EQ them they will not readily go into over excursion. Both posted max SPL are done in 1 Pi space. This is on purpose I understand that .5 Pi is a true corner. But few of us have a completely reflective concrete corner to put this into. If you do strap on another 3db on top. Both simulations are peaked out at 18mm X-max. This driver can do a clean 20 and over excursion to 22mm. So there is room for a bit more than 2 db more. Add in room gain and these boxes are almost flat to 20hz and 16 hz. So these are some real contenders. Definitly not available commercially. Oh did I mention that with 100 watts they can crack 120 db! muhhahahahha:R:R:R:R:R:R:R

Them that are interested vote. The one with the most votes is the one I build. This is a benevolent dictatorship after all!

Mark
 

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Discussion Starter · #4 ·
That is some crazy efficiency!
Yep!

But that is also why these types of speakers are so much fun to listen to. They are exceptionally clean in their low end reproduction. It is something that has to heard and gotten used to. But that being said they are in fact most lifelike.

The high efficiency works in our favor in that the horns track a signal that is very energetic much more quickly and cleanly than a vented or sealed enclosure. Just think how little cone movement is required to reproduce 100db! 1.5 mm. So yes there is the carzy big box. But some of the subs on the Shack are bigger and are strapped to kilowatt amps. This little babay beats them with less than a third of the power. The big boy even competes rather favourably with the Big Danley sub. With one less driver!

Mark
 

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Discussion Starter · #5 ·
What 66 views and only 1 votes! :huh:

Come on guys I need some dissenters and nay sayers as well as some votes.

Two people just don't have enough traction.

Mark
 

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Discussion Starter · #6 ·
For those who want to fool around with design ideas here are the input screens:

Mark
 

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Forgot to vote!

I like the Little Guy.

Horns/TL's have always interested me, as the level of performance that can be squeezed out of the system seems so disproportionate to more common enclosures. I would love to see how you end up folding this guy, and the in room response.
 

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I'm with Mike and Brian go with the little one:T
Thats some serious SPL:hsd:
 

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The little guy is my choice also.......:T
 

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Discussion Starter · #10 ·
Thanks Mike for the Poll. I should have figured out how to do that before I posted.

Mark

P.S. I voted for the little guy to.
 

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Discussion Starter · #12 ·
The big boy... you could christen it "The Eviction-ator."
Yeah Baby!

Now were talking. Even though I voted for the little one I must admit I'm contemplating the possibility of figuring out a fold for the Big Boy to. It's just to tempting. Just the bragging rights alone! 129 db at 16hz Yhoooow!

I built the UNHORN prototype to go down low enough in a car and it works great has moderate efficiency and great sound. But a real front loaded horn is a different animal when it comes to efficiency.

I look at it this way. The smaller one could be put in a corner and stuff piled on top or what ever. It's not small but not enormous either. The performance is great. But it would be oh so sweet to be able to reproduce the low end all the way down to 16 hz without fear of blowing anything up. Can't make it much smaller but a creative fold could make it somewhat in form factor like the Danley SPUDS. Flat and narrow. That makes it a bit easier to stick in a basement and hide it in a storage or mechanical room and shoot it into the listening room.

The smaller one I think is going to be a 48" x 16" by what ever it works out to box roughly 22½". The bigger one can go a couple of ways. Long and squareish ( I know it's not a word ) The Big Boy (Eviction-ator):devil: could work out like this: Say 15" x 24" x 94" long and low. Remember I make my boxes out of 1/2" material for the sake of box weight. If you brace it up properly there is next to no difference in rigidity and most materials like MDF for example are actually more rigid in the thinner panel. These prototypes will be made in OSB ( oriented strand board ) All glued and rabbeted in place and then braced up the wahzoo. All depends on the lay out saga to follow. That is always the most fun part. Fun like going to the dentist. If I had a dollar for every time I tried folding a horn I'd be a rich man!

Time to feed the little hamster that spins the wheel in my brain! Maybe I can come up with something useful on this one.

Mark
 

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I'm skeptical.

The simulations that you have shown would perform similar to or in many ways outperform the Tom Danley designed Labhorn which is: widely known as a monster among the professional sound arena, is much bigger, uses a pair of 12" drivers with higher power handling and has a cutoff of about 35hz and an intended range of only 30-120hz. This would be accomplished with a single moderate power 12" driver in a smaller enclosure, with a smaller horn mouth and almost an extra octave deeper of loading that somehow is much more efficient as well? I do not see how this is possible. If this is true every prosound outfit in the world would be using these types of cabs and we would have 16-20hz extension at concerts. We don't.

Also you have listed the power input as only 163watts give or take on the larger one, but your spl graph shows a gain of nearly 30db over the base, which is not possible unless the response graph showing about 105db at 100hz is for about 0.163 of 1 watt. Your 100hz efficiency would have to be about 113db at 1w and an astonishing 103.5 db at 16hz.
 

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Discussion Starter · #14 ·
Hi Ricci

It' good to throw in questions!

I'm working right now so I'll keep it short.

Your power assumption has been mislead by how Hornresp works when doing a sample . It calculates the frequency, the SPL, and the power into the load that the driver presents at that frequency. So you probably agree that close to Fs any driver is not at it's nominal impedance. You probably understand that 600 watts into 4 ohms is a voltage dependant variable. The amp driving a 16 ohm load will drop it's output to 150 watts . This is what is happening at the sample points as they are either just above or just below system resonance for this driver.

On the subject of low end. It is mainly a function of horn path length. The mouth size will support the low end to a greater degree when it is larger. This is apparent in the roll off at the low end.

Driver choice is because it is an excellent driver for this type of enclosure. It is very well put together and has almost double the X-max of the Lab12. That is the reason why it can compete with 2 Lab12's.

There are more points to discuss but I'm typing on my phones tiny keyboard and my fingers are not tiny! I'll post some more tonight as well as a simulation with the Lab12 on the same horns for a comparison.

Mark
 

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Discussion Starter · #15 ·
Hi Ricci I'm just finished work.

Some more info. The power input for the smaller box is 500 watts for max SPL plot. The max SPL plot for the larger box is 300 watts.

Most important is this fact. These are simulations! Although I greatly respect this program in it's ability to model things accurately it does so using the real world converted to mathematical formulas. I posted most of the graphs into 1 Pi because that is the best I ever get loading a horn into a corner which mathematically is .5 Pi. In real life expect about 3 to 4 db less efficiency. So more or less 98 to 100 db/watt loading these horns into a corner.

I greatly respect the work of Tom Danley. His Lab horn is a tour de force in heavy duty low end horn design. But he designed it for exactly what you have described. Production sound. No one in a home is going to push their subs to the same limits of continuous SPL that you find in the Pro sound world. We are dealing with loud and very loud transients. That is the second reason why one well designed driver can get away with what is simulated. We at home will never on a continuous basis be pushing a horn as hard as in a Pro environment. How many times at a concert or medium sized venue can you actually get proper corner loading? The difference as you know is 6 db in gained reflection. That four times the power. So I design a little on the edge knowing that a bit more performance can be squeezed out at the risk of driver longevity considering no one will really be pushing the horn so hard that driver longevity would be an issue. Almost everyone that has a horn loaded sub at home mounts it in the corner. It is the optimum location and this horn is designed for the optimum location. Not in the open or like the LAB horn to be used in stacks of three or more.

One more point. I have been working designing and building horns since 1995. Not a really long time but long enough to have learned a thing or two. First and foremost that simulations are just that. Close approximations.

As an example I followed a novel box design simulation that started as a what if kind of idea. A little down the design path I posted the results in the Unhorn proof of concept thread. It is to short to produce the low end output that it showed when simulated. That is until you take into account the tapping effect that the driver placement creates. It effectively doubles the length of the enclosure . The pinch point creates not a horn load but a sort of bandpass enclosure effect. It is neither a true horn nor a true bandpass box but a hybrid. It simulated well and measured well albeit with the drop in efficiency of about 3 to 4 db between the simulation and the measurements that I have always come to find when translating a simulation into real life. Squeezing that last bit out from a real world design is an evil task I wish on no one.

So much of creating a horn lies from the point of modeling to the creation of the actual horn. There is a real art to folding these beasts. And it is none to easy. I have been a cabinet maker for some 20 odd years. Not making kitchens but stuff furniture and fancy mill-work. And I have to admit to this that the Dual TRIO8 Unhorn took me three folds and almost a week of consternation. What Tom and other gents have presented is really good engineering. What I'm putting up here is an attempt at good engineering. The proof will be in the pudding.

This thread is a poll as to what some gents knowledgeable or just plain interested would think of either type of enclosure.

Below I simulated the two drivers ( Lab12 and TRIO12 ) in the smaller horn. At 1 watt and at 100 watts. Remember that this horn is designed for the TRIO12 and that is very important. The motors on the two drivers are very different in some respects as you shall see. One of the reasons why I chose 100 watts is because that is where the LAB12 runs out of excursion. The TRIO12 is just getting up to almost 1/2 speed at 100 watts. So taking this crude comparison two LAB12's would keep up with one TRIO12 in this horn. It would also allow a bit shorter horn path. But the overall volume would only go down slightly as the rear reactance annulling chamber would have to be larger with the two LAB12 drivers. The SPL would potentially go up by 3 db or double the power. But unfortunately 3 db is where normal untrained listeners just begin to hear a difference in SPL. So I'm not so sure it is worth it.



Mark
 

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Discussion Starter · #16 ·
I just ran the Butt Kicker through a simulation in AkaBak. It is a different program to simulate horn designs among other things. An interface from hell but it is quite accurate. When it looks good in AkaBak you have a decently close approximation of what it will sound like. Note that the program simulates the box in a 2Pi environment. That means outside on the ground. Inside against a wall with a floor and ceiling is 1 Pi and all the floor, wall, ceiling plus another wall to make a corner is .5Pi. Each boundary adds to the sound pressure level. So from outside to inside add 6db. Into a corner theoretically add 6 more db but in real life 3 to 4 db as not all corners are truly reflective at all frequencies. A basement you could call truly reflective if you are in a corner made with concrete walls.



Mark
 

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Mark,

Sorry I have been very busy.

I understand that these are simulations and that the applied power is not a constant amount due to impedance fluctuations. Mainly my point is that most people model their bass response in a half space environment at 1m and this is what they are used to seeing. Adding the extra gain due to boundary reinforcement, which may or may not be fully realized in reality is confusing and makes the enclosure appear much stronger to those that may not be aware of what is going on in the 1/8th space simulations.

Also normally the power input is specified as an amount that will not cause the driver to get into overexcursion at any point in the intended FR passband. Hornresponse is slightly irritating to me in the way that it keeps constant input power regardless of the impedance changes, so I understand where you are getting the input power from.

Perhaps show the halfspace max output hornresponse simulation in order to better compare it with the more popular "normal" builds of ported and sealed enclosures.

One final note is that the Lab12's actually do not run into excursion problems until well past 20mm one way. About 30mm inward seems to be the suspension "bottom". Limiting to 13mm is very conservative.
 

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Discussion Starter · #18 · (Edited)
View attachment 17442 Busy what's that!

Oh do I know what that feels like.

OK Ricci you must either be in Pro sound or have been in pro sound because you have a good grasp on whats going on. I have to admit I did not know the LAB12 was good to that level of X-max. But I have to work with something when I'm simulating sight unseen. They have to be grossly distorting at that level of excursion. From the modeling of the LAB12 that I have fooled around with the BL curve looks pretty nasty with that much excursion. But so does any other woofer as it gets pushed out of the X-max region unless it is an underhung motor design.

I did up the Max SPL within X-max for the TRIO12. It to can go beyond the stated X-max but from what I can remember not 30mm. If memory serves me correctly I think X-mech is 28 mm. Still pushing the limits for any driver to do this at length.

Below I post the results of the simulations. Happliy the horn is only -10 db at 20hz. So we all know what happens with decent room gain down there. The path length of the horn will support 20 hz the mouth will not. I chose the mouth size to give full loading to the vast majority of music and effects. It is well loaded down to 40hz. Below that depending on the locations of the boundaries the horn mouth is next to you should be able to get almost flat output down to 20hz ( with a good solid floor and corners )in the vicinity of 120 db with 500 watts input. The cool part is that with 100 watts your already blowing away most subs! The sad part is that from 100 to 500 watts we only roughly get an additional 7 db increase in SPL. The law of diminishing watts. I always find that after 500 watts you should just get more drivers if you want to go louder.
 

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Discussion Starter · #19 ·
I guess the voting thus far is three to one for the ahem.... smaller one!

It's a tough job running for votes and all that. But I'm guessing the people are speaking!

Mark
 
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