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post #151 of 448 Old 08-28-2010, 09:02 PM
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Originally Posted by LTD02 View Post

i was just curious if it could be lightened up with creative use of materials without reducing punching power.

Well... you could use 1/2"ply with strategically placed 3/4" dowels. Then do not install the bottom exterior wooden panel. Put weather stripping around the bottom of the three side panels, and use the ground as the missing side of the horn.
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post #152 of 448 Old 08-29-2010, 02:39 PM - Thread Starter
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Sigh...

Vas.

Why do you seemingly try to derail every one of my threads, with talk of politics and cars or obsessions over what is some minor detail in the final scheme of things? You continuously miss the forest for the trees and completely disregard many important aspects of a total finished speaker design that must be considered. Like the main design goals for example. Example: A few pages back you tried to tell me to use a different design with 4 B&C 12's and presented no data to support your view. You had wrongly assumed that I did not look at options such as that, when in fact I had and I posted that the performance really would not be much if any better, in some aspects probably worse, the design would be more complicated, more expensive and more challenging to build. Loss, loss ,loss IMO. I asked you to present something to support your claims and you did not. You let the subject drop. Your suggestions are all positives with no compromises in your eyes. Your last 2 pm's have convinced me. Especially the one about 30 SS Illuminator 6.5's outperforming an LMS. You should rethink that one and perhaps look at it a little closer. BTW I've seen a thorough non-public test on those drivers and it really wasn't that impressive to me. There are always compromises.

The JBL thing is yet another example. It is a failure right off of the bat due to missing the full power at 30hz corner design goal. Your thoughts or others on having extension that low are moot. I have heard every argument in the book against tuning that low instead of 40hz or higher and I know the trade offs in efficiency and output involved and they have been accepted from the get go. You are attempting to compare a smaller single 18" ported cab with less extension and power from JBL's flyable line array series to a larger horn cab? The extension and output differential would be quite large. You should probably be comparing a pair of those, or the larger double 18" version.
http://www.jblpro.com/catalog/genera...?PId=237&MId=4
>$4,500 each


Actually the correct comparison would be this from the JBL line.
http://www.prosoundservice.com/m9_vi...=JBL%20SRX728S

How about posting an actual competitive system of your own with data and design to back it up as I've asked you to before? Trying to convince others and me especially to change their build plans to more suit your own performance goals instead of theirs, will never work. You seem to believe that this is a total turd because you do not understand the reasons behind it. You think that you can do better. I'm asking you to post a superior competitive design here because I don't think that you can. So far you just seem like another one of the naysayers.


Soho, LTD02,

Weight is not that much of a concern. I figure it'll come in at <200lbs. 120lbs for just the cabinet seems about right. 80lbs for the driver. Construction will be 18mm birch ply. We routinely move around cabs that size and weight every month. 8x10 bass cabs are 160-170lbs, double 18's, etc. It will easily be handled by 2 men with casters and handles.
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post #153 of 448 Old 08-29-2010, 04:12 PM
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"hz?"

yes. good catch. changed.

"Weight is not that much of a concern."

cool. i just wanted to point out that you might be around the weight limit for one guy.

what kind of power are you thinking about?

if you happen to know, what is the excursion that causes damage in the lms?

if you have any klippels of the driver, that would be interesting to see, particularly how compliance (cms) varies with excursion.

i just had a totally random idea and not sure if it would work, but what about making some panels that are hinged on the top and sides that would swing forward and create a massive front horn, then fold back on to the sides and top for transport.

or maybe just two panels ~3 feet x ~3 feet each that swing forward to about 45 degrees in order to direct the sound pressure more forward.

i can't say that i have ever seen anything like that and it may be a total fail. just kick'n around ideas.

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post #154 of 448 Old 08-29-2010, 04:21 PM
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here is the idea:


LL

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post #155 of 448 Old 08-29-2010, 07:49 PM
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Originally Posted by Ricci View Post

Why do you seemingly try to derail

because i have a huge ego and i don't even notice other people over it

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Originally Posted by Ricci View Post

every one of my threads

your threads are more fun.

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Originally Posted by Ricci View Post

Especially the one about 30 SS Illuminator 6.5's outperforming an LMS. You should rethink that one and perhaps look at it a little closer.

why what's wrong with 30 illuminators ?

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Originally Posted by Ricci View Post

Actually the correct comparison would be this from the JBL line.
http://www.prosoundservice.com/m9_vi...=JBL%20SRX728S

that looks great !

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Originally Posted by Ricci View Post

You think that you can do better. I'm asking you to post a superior competitive design here because I don't think that you can.

you just posted one yourself.

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Originally Posted by Ricci View Post

Your suggestions are all positives with no compromises in your eyes.

yeah man. that's called trolling. ( or in case of my PMs, brainwashing ) why should i do all the work for you and point out all my own BS? you were given a brain for something - use it - point out where i am wrong

anyway i really want to hear your reasoning on why you think 30 illuminators won't outperform an LMS. but you must understand i didn't mean illuminator as a particular woofer - but simply as a small woofer in general. i am too lazy to even install winisd or any of that crap besides it won't run on mac anyway and i am too lazy to boot into windows. i am thinking in abstract terms here. there are three things that happen when you go to smaller drivers:

1 - diaphragm thickness decreases and surface area increases which directly results in enormous efficiency gain.
2 - the length of the magnetic flux loops through the iron of the motor decreases which directly results in saved weight for the same total amount of flux through the VC.
3 - the total surface area of voice coils increases increasing power handling

so we have less weight, more power and more efficiency - how can you go wrong ?

the only possibility here is that 30 drivers might need more box volume than 1 ... but i think that would be only because most 6" drivers are not optimized to work for small boxes while most 18" drivers are. you could probably optimize a 6" to work in 1 liter box such that 30 of them would work in 1 cu ft.

yo yo yo !

why don't you simulate for me ONE THOUSAND ONE INCH tweeters in 1 cubic foot. hm ? each one 90db/watt the combined efficiency would be 120 db/watt - not too shabby. somehow i doubt you could actually reach 120db/watt as i have never seen any horn drivers go above 112 db/watt or so - perhaps some other loss mechanism becomes dominant and the efficiency gain tops out. and the displacement of this array would be comparable to a single 12" woofer which would need as much volume - but would only be about 1% as efficient.

sure the tweeters would begin to roll off at around 1 khz versus 150 hz for a woofer which is 3 octaves at 12db/oct or ~30db which would bring the efficiency from 120db down back to 90db same as for the woofer ... but only below 150 hz. everywhere else it would be more efficient.

actually this is interesting. i don't really know which would be more efficient at lowest frequencies ! ! ! because the woofer has the advantage of higher VC speed which means the flux will be better utilized. E = FV so for the same Force there will be more Energy if the Speed is greater. so by going with an array you're taking the disconnect in acoustical mass and transferring it into an electrical disconnect with not enough back EMF for proper operation. CRAP ! ! !

can you simulate this somehow ?

you see 100% efficiency is only possible when impedance is 100% reactive. but with tweeters it will be almost 100% resistive in the bass which is why they won't put out much bass. this is the reason sealed boxes roll off at 12db/oct instead of 9db/oct predicted by hoffman's law. the extra 3db/oct comes from this electrical efficiency decreasing with frequency - the first 9db come from acoustical inefficiency.

there are too many factors to put them all into a formula which would tell you how to best produce bass. too many things change when you move to smaller drivers. i think it would be easier to just simulate them. but this is definitely one of those questions that we could both benefit from knowing the answer to.
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post #156 of 448 Old 08-29-2010, 08:27 PM
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Originally Posted by LTD02 View Post

here is the idea:


and how do you fold the bracing ?



next you should design a folding minivan that you can stow away under your bed when not in use.
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post #157 of 448 Old 08-29-2010, 11:04 PM
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"and how do you fold the bracing?"

off the top of my head, a reinforcing bar that fits into each panel at its midpoint or reinforcing bars that attach to the rear of the "wings" and to the sides of the main enclosure. that's small potatoes. the big question is does the idea have any merit? why or why not? how will it affect performance?

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post #158 of 448 Old 08-29-2010, 11:06 PM
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"next you should design a folding minivan that you can stow away under your bed when not in use."

is this your way of saying the idea has no merit or are you just trying to insult me for kicking out an original idea for discussion?

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post #159 of 448 Old 08-29-2010, 11:32 PM
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"why don't you simulate for me ONE THOUSAND ONE INCH tweeters in 1 cubic foot. hm ? each one 90db/watt the combined efficiency would be 120 db/watt - not too shabby."

a good tweeter, such as the peerless 810921 is about 93 db sensitive at 1w 1m at 3khz.

however, it rolls off pretty significantly below 2khz.

by the time you get down to 50 hz, it is about 40 db sensitive 1w 1m. ergo, a thousand of them would be 70db 1w 1m sensitive at 50hz. the driver in ricci's horn is about 88db sensitive in a sealed enclosure 1w 1m...and 97 db 1w 1m sensitive at 50hz in his horn.

even in the base case, using a high efficiency 1" tweeter, your 1000 tweeter choice is about 17db (50 times) less efficient as ricci's single 18" lms at 50hz.

at $72 per tweet, it would only cost $144,000 for a pair of subs. not practical, so let's explore the break even pricepoint. in order to bring the cost and performance to parity, you would need 50,000 tweeters for the cost of a single lms 18, or a per unit cost of 1.8 cents.

the $900 for a single sub and simplicity of design would seem to have the advantage over your proposed build with 50,000 tweeters that each cost 1.8 cents.

it was an interesting idea though...

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post #160 of 448 Old 08-30-2010, 05:01 AM
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Originally Posted by LTD02 View Post

"next you should design a folding minivan that you can stow away under your bed when not in use."

is this your way of saying the idea has no merit or are you just trying to insult me for kicking out an original idea for discussion?

well porsche panamera does have a folding spoiler so i think your idea is possible to implement in some conservative fashion such as folding the last 20% of the horn next to the mouth.

however the extra effort to design the system is not going to be worth it unless you're planning to build many of them. porsche can afford to fool around like this because they're selling thousands of panameras at $150,000 each.

design effort must be in the end economically justified.

also as BFM said most horns are designed for stacking. you need to think about that too.
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post #161 of 448 Old 08-30-2010, 05:04 AM
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Originally Posted by LTD02 View Post

even in the base case, using a high efficiency 1" tweeter, your 1000 tweeter choice is about 17db (50 times) less efficient as ricci's single 18" lms at 50hz.

we must understand the mathematical reasons why it happens.

you see the only point of a horn is to offset the high moving mass of a typical woofer with the high airload mass. however something like this tweeter array already has a low moving mass in relation to effective surface area so it is like a horn without the space requirements. the question is what goes wrong with the bass ? why doesn't it match the output of a lousy LMS ?

i have two ideas:

1 - not enough aluminum in the magnetic gap.

2 - not enough voice coil speed

problem is if we fix number 1 then we're back to where we started with LMS that is high moving mass !
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post #162 of 448 Old 08-30-2010, 10:03 AM - Thread Starter
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Originally Posted by vasyachkin View Post

because i have a huge ego and i don't even notice other people over it .

At least you are honest.

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your threads are more fun..

Thanks! I guess...


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why what's wrong with 30 illuminators ?.

Nothing inherently, but they do seem a little overpriced to me. The test I saw looked good but nothing exceptional. I was a little disappointed with the amount of effort that went into that motor.

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that looks great !.

It's one of the industry standard units basically. Very popular. It has solid performance for reasonable cost. I've heard them multiple times and it is good all around performance and bang for the buck.



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you just posted one yourself..

Yes, but I believe I can do a little better (extension, output, distortion, total cost) in the same cabinet volume. Actually there is a little more to it, but i'm keeping that for myself. Soho54 hit the nail on the head with one of his earlier posts. This whole build is basically a fact finding mission.



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yeah man. that's called trolling. ( or in case of my PMs, brainwashing ) why should i do all the work for you and point out all my own BS? you were given a brain for something - use it - point out where i am wrong .

Your troll chi is strong, but GL with the brain washing. You'll need it. Often I don't have enough time, or care enough to try to argue with you, or point out where I disagree. The fine art of willful indifference and obliviousness does have it's uses. You are exceedingly obtuse sometimes.

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anyway i really want to hear your reasoning on why you think 30 illuminators won't outperform an LMS. but you must understand i didn't mean illuminator as a particular woofer - but simply as a small woofer in general. i am too lazy to even install winisd or any of that crap besides it won't run on mac anyway and i am too lazy to boot into windows. i am thinking in abstract terms here. there are three things that happen when you go to smaller drivers:

1 - diaphragm thickness decreases and surface area increases which directly results in enormous efficiency gain.
2 - the length of the magnetic flux loops through the iron of the motor decreases which directly results in saved weight for the same total amount of flux through the VC.
3 - the total surface area of voice coils increases increasing power handling

so we have less weight, more power and more efficiency - how can you go wrong ?

the only possibility here is that 30 drivers might need more box volume than 1 ... but i think that would be only because most 6" drivers are not optimized to work for small boxes while most 18" drivers are. you could probably optimize a 6" to work in 1 liter box such that 30 of them would work in 1 cu ft..

I'll get back to you on this later. The major issues are fitting all of the drivers on a baffle or 3, and that pesky HIL, which limits your efficiency for a given bass frequency by the internal volume available. More drivers won't overcome this. They do provide power handling advantages and upper range efficiency boosts but not in the subwoofer range.

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yo yo yo !

why don't you simulate for me ONE THOUSAND ONE INCH tweeters in 1 cubic foot. hm ? each one 90db/watt the combined efficiency would be 120 db/watt - not too shabby. somehow i doubt you could actually reach 120db/watt as i have never seen any horn drivers go above 112 db/watt or so - perhaps some other loss mechanism becomes dominant and the efficiency gain tops out. and the displacement of this array would be comparable to a single 12" woofer which would need as much volume - but would only be about 1% as efficient.

sure the tweeters would begin to roll off at around 1 khz versus 150 hz for a woofer which is 3 octaves at 12db/oct or ~30db which would bring the efficiency from 120db down back to 90db same as for the woofer ... but only below 150 hz. everywhere else it would be more efficient.

actually this is interesting. i don't really know which would be more efficient at lowest frequencies ! ! ! because the woofer has the advantage of higher VC speed which means the flux will be better utilized. E = FV so for the same Force there will be more Energy if the Speed is greater. so by going with an array you're taking the disconnect in acoustical mass and transferring it into an electrical disconnect with not enough back EMF for proper operation. CRAP ! ! !

can you simulate this somehow ?

you see 100% efficiency is only possible when impedance is 100% reactive. but with tweeters it will be almost 100% resistive in the bass which is why they won't put out much bass. this is the reason sealed boxes roll off at 12db/oct instead of 9db/oct predicted by hoffman's law. the extra 3db/oct comes from this electrical efficiency decreasing with frequency - the first 9db come from acoustical inefficiency.

there are too many factors to put them all into a formula which would tell you how to best produce bass. too many things change when you move to smaller drivers. i think it would be easier to just simulate them. but this is definitely one of those questions that we could both benefit from knowing the answer to.

LTD02 basically covered this. The tweeters will never do it. Even your 30 6.5" drivers aren't really that efficient in the bass range. This is dominated by the enclosure size which sets an upper ceiling. Your 30 6.5's would be wanging up at 100-300hz for sure, but this has always been easy to do. People have built systems like this before. If you restrict your enclosure volume at some point you will hit the efficiency ceiling and if you keep adding drivers you will no longer gain any low end efficiency and will actually start losing it. You gain power handling and area, but at some point you also hit limits of what is a practical amount of power to try to provide. " Our 1 cu ft cube is designed to accept a 20,000w input capability for maximum headroom." This is basic stuff.

You wanted to jam 30 6.5's into the smallest enclosure possible. The smallest that you can realistically stuff an LMS into is 75L or about 2.7 cu ft. The 30 6.5's will have to be mounted on at least 4 faces of the enclosure (negative for the 6.5's) and 30 of them together consume more internal volume from the airspace as well, so they would end up with <2.7cu ft (negative for the 6.5's). The 30 drivers together also weigh more than the lms. (Another negative). They are more expensive. The build would be more tedious and complicated due to needing to wire up 30 drivers and cut 30 driver cutouts (More negatives). Also none of the ones that I have seen are optomized to work in such a manner. They don't have the right performance characteristics. The Illuminator 6.5's don't have enough motor force and really want a 15cu ft enclosure for 30 of them. (This would be larger than the horn for this build in the end. ) The Beyma 6P200ND's work in smaller enclosures but they don't have the right stuff either. You mentioned getting crazy efficiencies that would out do my LMS 30hz bass horn from something the size of a microwave. No. We are looking at the subwoofer range so anything above 120hz does not matter. The 6.5's will do great above 100hz, but are bad below. They'd be a great midbass.

30 SS 6.5's in 2.7 ft vs an LMS in 2.7ft. Both on the same power.
I'm not seeing this huge efficiency advantage. They are 1db less efficient at 60hz, 3db at 50hz, 4.5db at 40hz and by 30hz are 6db less efficient. Not a very good subwoofer. (Yet another negative.)
Attachment 184447

Same story with the Beyma's. They are a little better.
Attachment 184446

Comparing to the horn being discussed is laughable. I'm seeing 3-5db of efficiency advantage from 60-95hz for the horn and some 14db by 40hz and a huge 18db advantage by 30hz. The advantage stays at 12db or above below 30hz. The 30 6.5's do have an advantage above 100hz but again we are talking about subwoofers.
LL
LL
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post #163 of 448 Old 08-30-2010, 11:00 AM - Thread Starter
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here is the idea:


I like this idea. I don't know how practical it could be made to be, but it's novel. I'd worry about your hinge points not sealing.


BTW LTD02 I can't post any data from that or the LMS test that I saw because I don't own the rights. They aren't public information and in the case of the LMS I was specifically asked not to by the owner of the driver. It was 3rd party. It looked extremely linear, but they ran out of amplifier before getting into the outer limits. Xmech is 47.6mm inward where the triple joint smacks into the pole I believe.
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post #164 of 448 Old 08-30-2010, 02:45 PM
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Originally Posted by vasyachkin View Post

you see the only point of a horn is to offset the high moving mass of a typical woofer with the high airload mass. however something like this tweeter array already has a low moving mass in relation to effective surface area so it is like a horn without the space requirements. the question is what goes wrong with the bass ? why doesn't it match the output of a lousy LMS ?

You're missing some things.

Lowering the mass of the LF driver doesn't reduce the amount of air you need to move for LF output.

Tweeters have tiny xmax so you'd need hundreds of them.

Even so, LF rolls off at 12 dB/oct below Fs, so a 1000 Hz tweeter is down 60 dB at 30 Hz.

Instead of moving air the energy is going into all of those stiff springs and sunk in the power amp.

If they did have higher xmax their efficiency would be much lower from spreading the flux out.

Noah
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post #165 of 448 Old 08-30-2010, 09:44 PM
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at $72 per tweet, it would only cost $144,000 for a pair of subs. not practical, so let's explore the break even pricepoint. in order to bring the cost and performance to parity, you would need 50,000 tweeters for the cost of a single lms 18, or a per unit cost of 1.8 cents.

the $900 for a single sub and simplicity of design would seem to have the advantage over your proposed build with 50,000 tweeters that each cost 1.8 cents.

it was an interesting idea though...

Thank you for the laughs.
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post #166 of 448 Old 08-31-2010, 05:49 AM
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because i have a huge ego and i don't even notice other people over it

I always thought that people needed to have great success in life to have an ego. I guess I just learned that Ego can be a very delusional thing when it comes to those with zero success in life....go figure

It is not "open-minded" to reject knowledge - Bob Lee
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post #167 of 448 Old 08-31-2010, 07:03 AM - Thread Starter
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Just expanding on his comment in general. Your comment was correct about this TC driver, but it isn't really ideal for either. If you just look at it from the best TH or OD horn perspective ignoring the driver used it is true. .

It's been alluded too multiple times so far by Bill and also you and a few others that this driver really is not suited to this application, that a pro type driver would be better. Does anyone have a simulation of the same size and low corner that will prove this out? What we are looking for here is smoother response and higher efficiency. I would expect a noticeable increase. Anyone? I'm just not seeing it.

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Since you brought it up...
I have posted some of my concerns for these drivers before, but they were misunderstood, and the thread went to crap. I still have concerns, but the only way they will be relieved is by someone shoving one into a horn like this. There is nothing wrong with the sim itself. The question is if the driver can safely force it's way to xmax. If it can then the other drivers in the line should be able to do the same, and a bunch of new brute force horn builds will pop up every where. If it doesn't work out that way you will end up with a thermal limited MAX SPL similar to other drivers with less xmax, and better parameters. Worst case, the driver fails before either of these points would seem to be reached.

I am not trying to talk you out of this, as it needs to be done by someone, but I do believe in calling it as I see it. This way you will know the possible things to look out for in testing.

In this particular case the driver is no where near xmax until well below the knee. Up in the intended passband the excursion doesn't break 20mm even with 124v input (4000w). That's about the maximum amplifier size I'd use on a single cab. This is not some sort of huge excursion maximizing design. I just looked at what had the best combo of efficiency, excursion headroom and power handling. A different design would be more useful to test your excursion questions. The double 12" xxx, 12hz TH that I'd like to build for example.

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Whatever you wish. I'm more a scrap wood BFM type, or dowels if space is a real premium.

I figured arauco or birch ply 3/4".

Yes. Birch ply 18mm.

I figure on one good sized brace in the mouth section and another on the back panel. Maybe one in the turn by the driver too. Sound about right?

What about lining? Lightly in a few of the bends corners? I figured on no stuffing in the sealed chamber.
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post #168 of 448 Old 08-31-2010, 07:25 PM
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Originally Posted by Ricci View Post

You are exceedingly obtuse sometimes.

blah blah blah. you proved me wrong with your simulation - great. but what did you learn ? that is the question.

you can't get ahead by doing simulations. you can only get ahead by gaining a deeper insight.

so i have suckered you into providing some useful data, now the question is - can we make sense out of it ?

that is to say WHY do these different designs have these different levels of performance ?

i just got back to NY yesterday. on the way i made some progress in developing a framework that can be used to compare a sealed box to a horn in an apples to apples fashion to see if one technology has any fundamental advantage that isn't implementation related.

with 30 illuminators vs LMS we have a more or less apples to apples comparison - we are comparing a 3 cu ft box to a 3 cu ft box. it is not so straight forward with horns.

i have also had a revelation - that very large systems in large venues present a fundamentally different engineering problem than do small rooms and small systems.
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post #169 of 448 Old 08-31-2010, 07:40 PM
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Originally Posted by Ricci View Post

Yes, but I believe I can do a little better (extension, output, distortion, total cost) in the same cabinet volume. Actually there is a little more to it, but i'm keeping that for myself. Soho54 hit the nail on the head with one of his earlier posts. This whole build is basically a fact finding mission.

you're keeping secrets from me you ass ?

i give you all this food for thought and this is how you reward me ?

tsk tsk

better get your act together Josh
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post #170 of 448 Old 08-31-2010, 07:56 PM
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Ok Ricci listen to this and then understand it:

i think it was Einstein that said that "a problem cannot be solved at the same level of understanding that created it" or something like that.

you are currently at the level of understanding of Thiele-Small theory, WinISD well and HornResp. that is to say you know nothing that anybody else doesn't. how do you hope to out-do everybody else when you are on the same page as they are ?

you don't need to invent a new type of product. but you do need to at least invent a new AND BETTER way to understand current products THEN you will be able to better optimize them than anybody else.

i am too lazy to think about it myself, but formulas must be developed that tie all of the factors together into a unified acoustical theory so to speak. einstein never did manage to get his unified theory he was after though.

we need a mathematical tool that will tell us unequivocally which is way to design a system that produces most bass from smallest size and weight.

we need a means of apples to apples comparison between horn and direct radiator AND an apples to apples comparison between few big drivers and a lot of small ones. i have been trying to trick you into thinking in that direction but instead you are complacent with just calling me obtuse.

tsk tsk
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post #171 of 448 Old 08-31-2010, 08:11 PM
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Originally Posted by vasyachkin View Post


we need a mathematical tool that will tell us unequivocally which is way to design a system that produces most bass from smallest size and weight.


tsk tsk

can we assume that, in the case of this build, low distortion/linearity can be added to the design goals? And possibly efficiency as well?
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post #172 of 448 Old 09-01-2010, 06:23 AM - Thread Starter
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can we assume that, in the case of this build, low distortion/linearity can be added to the design goals? And possibly efficiency as well?

Yes. I'm very interested in what the distortion levels will be like. Horns are generally held to be very clean in their intended range of operation. The LMS driver is very low distortion compared to the other big subwoofer drivers that I've seen data for, which admittedly is not a large sampling. Hopefully it's a great pairing.
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post #173 of 448 Old 09-01-2010, 06:46 AM - Thread Starter
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blah blah blah. you proved me wrong with your simulation - great. but what did you learn ? that is the question..

Nothing in that case. I already knew what the outcome would be. The simulation was simply because you wouldn't believe it otherwise. The 6.5's simply don't have the correct motor force to cone area/suspension stiffness mix needed. There may be some that do, but I don't know of them. 4500cm^2 is too much cone area to maintain LF efficiency in a box that small.

Quote:
Originally Posted by vasyachkin View Post

i just got back to NY yesterday. on the way i made some progress in developing a framework that can be used to compare a sealed box to a horn in an apples to apples fashion to see if one technology has any fundamental advantage that isn't implementation related.

with 30 illuminators vs LMS we have a more or less apples to apples comparison - we are comparing a 3 cu ft box to a 3 cu ft box. it is not so straight forward with horns..

Well what is the framework for a direct comparison then? I already have my own ideas on this so I want to see where you are at. You probably have a different take on it than I do, as usual.

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i have also had a revelation - that very large systems in large venues present a fundamentally different engineering problem than do small rooms and small systems.

This is a revelation?

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Originally Posted by vasyachkin View Post

you're keeping secrets from me you ass ?

i give you all this food for thought and this is how you reward me ?

Hey you are the self proclaimed genius with all of the ideas. I'm just a guy who likes sound enough to try building things.
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post #174 of 448 Old 09-01-2010, 07:39 AM
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how do you hope to out-do everybody else when you are on the same page as they are ?

Im not sure the context of that POV but in the real world people can simple spend more then others do

Ricci, buys products that most people would never buy and enjoys building great subs. He already is "out-doing" 99.9% of the population and 99% of all other DIYers.

I doubt he really even cares about "out-doing" anyone anyways. He just wants pure performance.

If the question is about "out-doing" someone like Danley. Lets just forget about that!

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post #175 of 448 Old 09-01-2010, 07:42 AM
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Originally Posted by vasyachkin View Post

you're keeping secrets from me you ass ?

i give you all this food for thought and this is how you reward me ?

tsk tsk

better get your act together Josh

lol, I have not read a post from you that has helped Ricci but you think you are guiding him

Why can you not just go build some subs or speakers instead of posting telling everyone how smart you are constantly? (I know the answer but I always love reading why you can't )

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post #176 of 448 Old 09-01-2010, 10:52 AM
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Hey you are the self proclaimed genius with all of the ideas. I'm just a guy who likes sound enough to try building things.

you are beginning to sound like penngray. i'll call you grandpa.
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post #177 of 448 Old 09-01-2010, 05:08 PM
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Post 167

I'm not really sure how to respond here. I have never said anything about pro/HiFi drivers.

It is pretty easy to get another 4-5dB sensitivity, and a flatter response in the same bandwidth with a horn the same size to a little smaller. The trick is to design a horn, and not a TQWT. Several of the drivers listed in this thread, and about 3min should do it. You will be sim limited to ~130-135dB with them. The DSL numbers indicate another 3dB could be possible over that.

From the rest of your post it seems you are holding things too close to your chest, as I am not able to follow your reasoning. No matter as the rest of my post still applies, "If it can then the other drivers in the line should be able to do the same, and a bunch of new brute force horn builds will pop up every where. If it doesn't work out that way you will end up with a thermal limited MAX SPL similar to other drivers with less xmax, and better parameters. Worst case, the driver fails before either of these points would seem to be reached." I'm not sure that excursion headroom is that big a deal in a horn though.

I would rather not go into this much further in this thread though. It is bogged down enough already.

There is no need for lining in an OD folded horn.

I have been fighting a PITA rootkit all week/weekend, and haven't been able to finish the sim yet. I got rid of the last hold out yesterday, so I'll post it up this weekend.

EDIT: That should be 3-5dB not 4-5dB.
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post #178 of 448 Old 09-01-2010, 07:44 PM - Thread Starter
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It is pretty easy to get another 4-5dB sensitivity, and a flatter response in the same bandwidth with a horn the same size to a little smaller. The trick is to design a horn, and not a TQWT. Several of the drivers listed in this thread, and about 3min should do it. You will be sim limited to ~130-135dB with them. The DSL numbers indicate another 3dB could be possible over that.


Can I see one? In all seriousness here. The above quote is what I was getting at. I haven't been able to get that extra 4-5db without significantly raising the corner. My horn powers are novice at best. I'd like to have a look at the sim for something that is drastically more efficient. The Labsub is but it is also much bigger.
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post #179 of 448 Old 09-01-2010, 08:00 PM
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I haven't been able to get that extra 4-5db without significantly raising the corner.

You won't, because the cab is too small. There is a limit to how low you can go with a horn cab of finite size, and you've gone past it. Hoffman always wins. From the size box you want to use I'd say a 40 Hz corner frequency is about as low as you want to try for using only one cab. With a 40 Hz Fc you want to use a driver with an Fs in the 35-45Hz range, which gives a lot lower Mms, and that allows a lot lower Qes and higher Bl from a smaller magnet, while the higher sensitivity allows less Vd for the same output. BTW, though I've never tried it myself to find out, standard design practice is to keep xmax at 15mm or so. More than that invites throat distortion, if not shredded cones. That potential is what limits the potential for 'brute force horns'.

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post #180 of 448 Old 09-01-2010, 08:33 PM
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You know what is a shame? That their is some great info posted by most people (vasyachkin excluded) and I have been following the thread since Ricci started it, but you have to sift through vasyachkin's constant ******** posts to get to it.

I have seen some real idiots on the net, but this guy takes the cake.

My build thread

My 8 x RE XXX 18" Subwoofers, IB build
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