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DIY bass horn build...Up next - Page 3

post #61 of 448
8/22/10 at 8:50pm
Quote:
Originally Posted by Ricci View Post

I did try smaller drivers and some of them would have better efficiency but they don't have the displacement or power handling to maintain linearity. Efficiency is great but it can be over rated with out context of power handling and driver displacement also considered. IMHO of course. This is the missing parameter from the over inflated power handling and output specs many pro audio manufacturers provide. The newer Danley subs seem to be leaning towards the type of combos that I have been curious about. Th118 and the new double 18 flh in the same form factor as the labsub specifically.

the horn will limit the drivers' excursion plus as the horn only works above 30 hz you will be cutting the drivers below that frequency so LMS's xmax won't be needed. 9 mm xmax should be plenty and 4 X 12" B&C should have more thermal power handling than the LMS, and way more mechanical power handling.

you can't be smarter than EAW. only i can do that there is a reason they use 12" PA drivers in their horn and it's not even that difficult to figure out ( if you're a genius like me that is ).

and why do i hear you talking about linearity in a PA subwoofer ? that's like talking about health benefits of a cheeseburger.
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post #62 of 448
8/23/10 at 6:25am
Quote:
Originally Posted by Ricci View Post

Efficiency is great but it can be over rated with out context of power handling and driver displacement also considered. IMHO of course. This is the missing parameter from the over inflated power handling and output specs many pro audio manufacturers provide. .

That of course goes to the industry norm of listing only Pe with no regard given to displacement limited power, and of course the ultimate silliness of 'calculated maximum SPL' that considers neither displacement nor thermal power compression.

Where higher sensitivity versus higher Pe and xmax as the route to higher output is concerned, I'll always take the former. Both roads get you to the same place, but higher sensitivity gets you there at a far lower cost.

As for Tom's recent leanings toward larger drivers with higher Pe ratings, IMO that's as much a marketing as an engineering decision. Even in the ranks of pro-sound operators who should know better the 'bigger drivers/more power is better' notion is pervasive, so creating products to appeal more to their wants rather than needs is just good business.
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post #63 of 448
8/23/10 at 7:38am
Thread Starter 
Bill,

I don't believe that Tom engineers subs with a leaning toward marketing over performance. I just don't. He tries to meet certain goals within his design constraints and I don't believe that marketing starts out by adding one that says "BTW we want to use this exact driver model or this driver compliment.". I also refuse to believe that after he spends the time designing a new system that he will be told "That's nice Tom but our customers are going to want 18's so please don't use 12's even if the performance is a little better".

The smaller drivers that I have simulated in a similar enclosure size/extension do not have much better sensitivity at all, usually less and run out of excursion with power levels that a moderate sized pro amp would be able to easily provide let alone the larger pro amps available these days. Unless you use a large amount of cone area and motors like Vas suggests with the 4 12's. Horns provide a better leveraging on the drivers output and so does keeping the F3 high but in the end it still takes a lot of displacement to make bass. The constraint in this build is the total enclosure size and a 30hz corner.


Vas,

4x12's is about 2000cm of cone area and a lot of baffle area which is going to be very difficult to fit in an enclosure this size. 1200cm is hard enough already. Instead of simply assuming some things, why not suggesting a specific alternate build and showing a simulation of it? I've already done a ton of it and this was one of the best ones based on efficiency, power handling, and excursion headroom. Here are the 4 NW100's in the same basic enclosure size and the same total amount of power into the minimum impedance. The lms sim is gray. I could probably optomize it a little more but they want a larger enclosure for a smoother response.


Attachment 183763
LL
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post #64 of 448
8/23/10 at 7:49am
Quote:
Originally Posted by Ricci View Post

I also refuse to believe that after he spends the time designing a new system that he will be told "That's nice Tom but our customers are going to want 18's so please don't use 12's even if the performance is a little better".

What Tom does at his workstation and what his marketing department tells him they need are going to be perpetually at cross-purposes. Tom's mindset isn't far removed from mine, in that he also leans towards Porsche performance standards in a world that still thinks a three ton SUV is a practical vehicle.

Quote:


The constraint in this build is the total enclosure size and a 30hz corner

No doubt, which opens the can of worms as to whether 30Hz is a worthwhile goal for pro-sound. For DJ use, sometimes. For live sound, rarely.
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post #65 of 448
8/23/10 at 8:07am
Quote:


in that he also leans towards Porsche performance standards in a world that still thinks a three ton SUV is a practical vehicle.

That is a cool quote!!

Ricci, I probably missed it but what is your highest Frequency goal of this design?

I have been wanting horn bass bins ever since I started playing around with waveguides but I have yet to find the right design that goes high enough.
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post #66 of 448
8/23/10 at 9:11am
Thread Starter 
The main target is 30-120hz. 2 octaves. Useful from 25 to 150 I guess.
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post #67 of 448
8/23/10 at 3:41pm
"Can you post up a zip of your word file. I am very interested in your method. It would really speed up trial and error time for me."

 

msword version ricci horn mockup.zip 11.1171875k . file
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post #68 of 448
8/23/10 at 4:44pm
"That is a cool quote!!"

maybe, but it misses the point.

bfm and td have made good subs using mediocre parts in the past (among other things, the variable vains in porsche's turboes represent the cutting edge in tech). in some of the more recent designs, td is using higher-end components in order to hit higher end performance in cabs of the same size. the tradeoff is they cost a little more. the whole industry is moving toward higher quality components though, so in order to keep his lead, he must do the same.

dual lab 12's model quite similarly to the lms ultra, but run out of gas (xmax) long before the single ultra does. ricci's choice is actually not a bad one, even though we don't typically think of large xmax drives in horns. this is not because a dual lab horn sub in ricci's design will sound poo-poo. far from it. it would have been cutting edge just a couple years ago.
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post #69 of 448
8/23/10 at 6:11pm
Thread Starter 
FWIW I do also have a FLH and TH design for the 21" B&C in the same basic cabinet size if anyone thinks the LMS build is catastrophically flawed.
The performance of the 3 is close enough to be a toss up.
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post #70 of 448
8/23/10 at 6:16pm
Quote:
Originally Posted by Ricci View Post

FWIW I do also have a FLH and TH design for the 21" B&C in the same basic cabinet size if anyone thinks the LMS build is catastrophically flawed.
The performance of the 3 is close enough to be a toss up.

A Cinemonster clone with the B&C 21" would be right up my alley. How bout it?
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post #71 of 448
8/23/10 at 6:21pm
Actually variable geometry turbochargers have been used for a long time in commercial turbodiesel engines. Porsche is simply the first one to apply them to regular gas powered cars.

Porsche is still number 1 at design and innovation though.

Porsche only has 5 cars in their lineup yet somehow no matter what type of car you're looking for chances are the best one will be a Porsche. The only reasons not to get a Porsche are:

1 - you can't afford it

2 - you don't like the styling

but those things are not up to the car company. your budget certainly isn't and your taste is subjective. porsche covers all of the bases on their side - ergonomics, performance, fuel efficiency. no other company does.

the second best car maker after porsche is BMW, but porsche holds a comfortable lead.

let me go ahead and rate car companies by their IQ:

Porsche - 150
BMW - 130
Mercedes, Toyota/Lexus - 125
Subaru, Nissan/Infinity - 120
Honda/Acura - 115
Ford - 105
GM, Chrysler - 100
Hyundai - 95
Mazda - 90
Kia - 85

Frankly if i was Hitler i would take every company below Honda/Acura, line them up against the wall and mow then down with a machine gun. We as a planet have no use for those inferior retards.

The only cars worth driving are German and Japanese. Italians cars are a form of art rather than transportation. Korean cars are for people who can't afford to take the bus and American cars for people who were either born without a brain or need a pickup truck.
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post #72 of 448
8/23/10 at 9:24pm
well vas, you lost all cred with that post.

ferrari has about the highest hp per volume of any street car. why? technology. the geometry and timing of the intake creates football shaped molecules that burn faster than the round globules in most motors. then there is the skyline or whatever it is called today. oh yea, and a little heads and cam pack can put a vette way up on the list. have you looked at the fastest lap times at the nurburgring lately?

the lms horn is in no way a catastrophic failure (assuming the driver can survive). jeez, this thread is getting looney. the lms horn is a monster, if unconventional.

the 21sw152 works well in a tapped horn. one model that i kicked into the old build thread:

Ver=24.00
Ang=2.0 x Pi
Eg=116.62
Rg=0.00
Fta=0.76
S1=560.00
S2=570.00
Con=25.00
F12=0.00
S2=570.00
S3=1800.00
Con=325.00
F23=0.00
S3=1800.00
S4=1850.00
Con=25.00
F34=0.00
S4=0.00
S5=0.00
L45=0.00
F45=0.00
Sd=1680.00
Bl=32.50
Cms=4.50E-05
Rms=13.75
Mmd=467.48
Le=1.50
Re=3.40
TH=1
Vrc=0.00
Lrc=0.00
Ap1=0.00
Lpt=0.00
Vtc=0.00
Atc=0.00
Com=Ricci horn w/21sw152 driver

since the 21sw152's are already deployed, i see no reason to go that route.

the lms horn is a bold move that pushes the limits. i'd like to see it go forward.
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post #73 of 448
8/23/10 at 9:27pm
"A Cinemonster clone with the B&C 21" would be right up my alley."

come on...at 480 lbs., that is in no way a portable p.a. solution.
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post #74 of 448
8/23/10 at 10:10pm
Lolz! I am talking about for home duty, of course.
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post #75 of 448
8/23/10 at 10:36pm
at the least, i'd break that one apart in two separate subs for home duty, but we are talking about portable p.a. in this thread. scott, you are a very advanced member. recognizing the constraints and identifying the builds that take each person to the next level is your goal now. ;-)

ricci's choice looks surprisingly good to me. let's hammer on his design if possible. the only thing that i see as a *possible* weak link is the compression ratio. it may hold at 3:1. other than that, it looks very good for its purpose. i'd even go so far as to disagree with bfm about the mouth size. the model is showing relatively flat response to 30hz, so what does a larger mouth provide in this design? a little more efficiency? sure, but now you are talking about a larger horn. ricci spec'd 380 liters. in that context, his design seems to make good tradeoffs between extension and efficiency. for its purpose, this design seems to hit on all cylinders.
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post #76 of 448
8/23/10 at 11:30pm
example of song with strong 28hz (and some 16 hz hits) content throughout.

just confirming the good tradeoffs inherent to this design. ;-)


LL
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post #77 of 448
8/24/10 at 1:18am
Quote:
Originally Posted by LTD02 View Post

well vas, you lost all cred with that post.

ferrari has about the highest hp per volume of any street car.

in your dreams son.

Porsche 911 GT2 RS:

3.6 liters 6 cylinder -> 620 horsepower. that's the same as Corvette ZR1's 6.2 liter and more than any Ferrari V8.

As for GTR/Skyline it is a piece of junk like everything nissan builds. It's not a complete car. It's just a very fast turd. You could just get some dog sh1t, load it up into a shotgun and fire - same result for much less $$$.

Nobody can touch Porsche. NOBODY.

Tell me who comes even close to 70 mpg in a 700 horsepower car like the new Porsche 918 Spyder ?

forget it ...
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post #78 of 448
8/24/10 at 5:44am
Porsche vs Ferrari is a silly arguement. Both are awesome, both are owned by very few, both go extremely fast, both are far beyond any power needed.

Anyone arguing them has lost any sense of reality.

I would also say that those who can not remotely afford those cars should stop posting about them because you know squat about money, power and going fast

People have to stop arguing with Vas because if you realize he does not own a home or a car, he does not have a wife or a girlfriend, he does not have kids. You would finally realize that he lives in some obscure fantasy life online and every response feeds his little delusional world.
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post #79 of 448
8/24/10 at 9:20am
i forgot to post what song that spectrum lab was for. the ~30hz corner makes sense because more and more music is heading lower and lower. this one has massive bass even though the bass isn't the main thing.
http://www.youtube.com/watch?v=WTJSt4wP2ME

vas, as you know, turbo vs. non turbo is apples to oranges. heck, an evo can be blown to higher hp per liter than the quarter of a million dollar gt2rs. the genius in the cars mentioned is not so much in the motors but in their handling. unlike americans, the europeans understand that the primary benefit of high hp per liter is that it keeps the engine weight down, which improves handling. its kind of like ricci's sub...maximum performance per liter because you have to move it around. ;-)
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post #80 of 448
8/24/10 at 12:06pm
Thread Starter 
Quote:
Originally Posted by soho54 View Post


Soho54,

Concerning Vtc, Atc and Ap1, Lpt1...Assuming that my throat area is as depicted above, the cut out is 1430cm and the volume inside the cone, plus the removed wood, minus the surround is about 4000cm in volume, is this the correct data entry under those 4 parameters?



Attachment 183910


This is the updated input with the increased 90L rear volume, driver parameters and parabolic horn sections. This has added about 40L to the horn schematic. 15L from the rear volume and 25L from switching to parabolic. The only actual volume increase in the enclosure build would be from the driver back chamber though.
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post #81 of 448
8/24/10 at 12:16pm
Thread Starter 
Quote:
Originally Posted by LTD02 View Post

"Can you post up a zip of your word file. I am very interested in your method. It would really speed up trial and error time for me."

I like that folding scheme. It keeps the driver more or less horizontal whether with the mouth firing from top, bottom or with the enclosure lieing on either side.

I'm a bit vague about how you are approaching this in your ms file though. How are the clearances and lengths being determined using this method?
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post #82 of 448
8/24/10 at 1:18pm
attached is a "quick and dirty" guide. it works backwards from the mouth to the throat, but you can use the same method to work 'forward' from the throat to the mouth. i haven't got it all figured out yet, so it is still a little bit of an art vs. an elegant mathematical solution. the latter shouldn't be far away, since all this is just math, but i don't want to invest the time to code it all up. ;-)

 

folding up a horn.zip 15.083984375k . file
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post #83 of 448
8/24/10 at 8:03pm
Quote:
Originally Posted by Ricci View Post

Soho54,

Concerning Vtc, Atc and Ap1, Lpt1...Assuming that my throat area is as depicted above, the cut out is 1430cm and the volume inside the cone, plus the removed wood, minus the surround is about 4000cm in volume, is this the correct data entry under those 4 parameters?

At normal levels the 1430cm is a bit too much. The surround displaces the wood, so you should use the area between the inside surround edge. If the driver moves rearward enough you could lower the surround below the plane of the baffle, and expose the cutout volume, but I don't think it will make much of a difference anyway. A ~3/4" inch port at close to Sd only shifts things down around a couple of hertz, and this should be less than that.

I will caution not to take the horn liter figures to literally. Both folds so far eat up over 500l. A safe guess is +100l to whatever HR gives you raw.
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post #84 of 448
8/25/10 at 10:31am
Quote:
Originally Posted by LTD02 View Post

i forgot to post what song that spectrum lab was for. the ~30hz corner makes sense because more and more music is heading lower and lower. this one has massive bass even though the bass isn't the main thing.
http://www.youtube.com/watch?v=WTJSt4wP2ME

vas, as you know, turbo vs. non turbo is apples to oranges. heck, an evo can be blown to higher hp per liter than the quarter of a million dollar gt2rs. the genius in the cars mentioned is not so much in the motors but in their handling. unlike americans, the europeans understand that the primary benefit of high hp per liter is that it keeps the engine weight down, which improves handling. its kind of like ricci's sub...maximum performance per liter because you have to move it around. ;-)

Yes an evo can blow but it has no low end torque, no fuel economy and it's ugly. Gt2rs has 500 lbs torque @ 2krpm and good fuel economy.

Americans can build a car that handles - they do this for NASCAR etc after all. What Americans can NOT do is deliver the whole package.

The whole package means power, handling, braking, fuel efficiency, interior and exterior styling, ergonomics, storage organization and bad weather traction.

Porsche panamera gets it all with possible exception of exterior styling which to me looks hot personally. Bmws come close but always fall short somewhere. Japanese copy BMW the best they can and americans just say screw it we'll make a piece of junk because there are plenty of retards and somebody will buy it.
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post #85 of 448
8/25/10 at 10:38am
The Cadillac CTS-V is the fastest 4 door sedan on the planet with great reliability ratings. Why are you so arrogant?
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post #86 of 448
8/25/10 at 10:38am
Thread Starter 
Quote:
Originally Posted by soho54 View Post

At normal levels the 1430cm is a bit too much. The surround displaces the wood, so you should use the area between the inside surround edge. If the driver moves rearward enough you could lower the surround below the plane of the baffle, and expose the cutout volume, but I don't think it will make much of a difference anyway. A ~3/4" inch port at close to Sd only shifts things down around a couple of hertz, and this should be less than that.

I will caution not to take the horn liter figures to literally. Both folds so far eat up over 500l. A safe guess is +100l to whatever HR gives you raw.

Ok. Sounds like I should use SD basically and revise my estimate a little. It doesn't seem to affect the sim too much either way.

About the schematic. I understand that is only the internal horn volumes for a straight horn and that the final volume and especially external volume will be much greater. I was only mentioning that the internal volume has increased some from before.

It looks like we may be close to having the simulation tweaked out enough to give this a shot. What do you think of LTD02's fold scheme? Look workable?
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post #87 of 448
8/25/10 at 1:23pm
at 5000 watts, i'm only getting about 21 mm of excursion at about 133db at 50hz.

i don't recall seeing a klippel of bl vs. excursion for the lms, but that 21 mm is probably almost linear. this is a 130db+ linear sub in the making. you are shooting at danley and i think you may have him.

i'm a little befuddled by the specs on the th118, a single 18" 15 cubic foot tapped horn, quite similar, more or less, to what you have here. the spec sheet shows 105db at 40hz w/ 100 watts at 10 m. translation: 105db at 40hz w/ 1 watt at 1 m. that is ten times higher sensitivity than i am seeing with any horn of this size. td has been at this long enough to know that is wrong. wtf?
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post #88 of 448
8/25/10 at 1:33pm
just to give that last comment a little context, 105db 1w1m spl 1/2 space sensitivity would be equivalent to TWENTY jbl 2242's 8 cube ported 25hz tuned standard pro-cinema subwoofers or TEN of ricci's lms horn subs.

hedden is getting carried away...i'm just sorry that td has to deal with this.
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post #89 of 448
8/25/10 at 1:50pm
red line is th118 horn (from the spec sheet)
black line is ricci lms horn (hornresp model)
green is th118 phase (ignore)

we know hornresp models are accurate based on several model vs. measured horns. even if the th118 was measured in artic conditions (-30 degree temps), that would only add about 2 db. something is wrong.


LL
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post #90 of 448
8/25/10 at 2:43pm
Thread Starter 
Calm down there LTD, you are overlooking a critical piece of information which is the impedance measurement they provide. I've come to regard an impedance measurement as one of the most useful.

Those Danley graphs are not efficiency graphs, or referenced to 1w either. They are 2.83v voltage sensitivity graphs. The impedance is dropping well below 3 ohms in some places. The one that you are referencing from my simulation is a 1w limited graph at 1.97v into the minimum impedance of just under 4ohms. Basically they are not apples to apples. It is tricky to do apples vs apples really, especially from a marketing competition standpoint. A nominal 2 ohm cab will look much better with a 2.83 volt input than a nominal 8ohm cab, but the 8ohm cab may in reality be the more efficient one.


BTW 21mm is nothing for an LMS (I've seen a klippel report and played with the drivers quite a bit.) Geometric xmax is 30mm. 70% BL is at 38mm one way. Xmech at 47.6mm.
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AVS › AVS Forum › Audio › DIY Speakers and Subs › DIY bass horn build...Up next