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Old 8th October 2006, 08:55 PM   #1
Variac is offline Variac  United States
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Default This is Split off from another thread

This thread is split from :

How should I wire my 1500 watt speakers?

The original thread was started by Mr. Punkrockr looking for a speaker design that met his needs. Now that he has decided on this design it will be easier to have it in its own space...


***********************************************




Hey Scottmoose and everyone else!!!:

How about something like this but with a 12" driver:
HOW ABOUT USING THAT 12" Eminence with whizzer that Pano (and other people) loves!!!

http://www.zillaspeak.com/BibBassHorns.asp
(Scottmoose is in the middle of these designs he knows how to design them..)

See pics of small versions with 6 or 8" drivers
http://www.zillaspeak.com/bib-pics.asp

imagine cabinets this tall, but instead of being about 8" wide, they'd be about 18" wide!! HUGE!!! (those drivers in the photos are 6 inch I believe...)

(as Pano has mentioned , the Hammer Loudspeaker
(not the same people that sell the Hammer drivers) uses almost exactly this 12" driver full range with a small supertweeter.

http://www.hammerdynamics.com/



-Punk could see his driver as it won't be bundled inside of a horn.
-Big 12" driver
-Loud as hell
-Huge cabinet!
-simple crossover - possibly the Hammer one works fine- just a supertweeter at the highest frequencies possibly. Maybe some shaping down low.. We need to look at the Hammer crossover- it is all over this forum..Quite possibly the horn will accomplish a lot of what the hammer "crossover " does as far as any shaping...

Hey, guys, I think this might be it! Loud, cheap, and easy- always desireable characteristics in people or speakers!!!! Please consider this everyone. This could be the best party speaker price/performance ever!!!

Total driver cost about $150 for TWO speakers!!!And it would have many of the desireable full range characteristics.Much more coherent than a multiway PA style!.The increased bass might counteract the rising response, AND handle Baffle step.

http://www.partsexpress.com/pe/pshow...90-409&scqty=2

Specs:
http://www.partsexpress.com/pdf/290-409s.pdf

Now I know some of you are concerned about the wiggley nature of the response, but keep in mind that all full range drivers plot pretty rough, but other fine characteristics they have balance this out. Look up the popular Fostex's to see this, but keep in mind Fostex smooths their curves radically so they are worse than shown.

Another tweak is to roll off the bass some as Nelson Pass does on the J-Low to limit excursion, but I don't think this will be a problem with a 12"

The horn won't go super low, but as has been mentioned here many times, Punk needs LOTS of bass, not low bass, AND I think these would be actually quite good sounding. And at about 100db/watt efficient- Punkr can just about use a Sonic Impact amp
with 10 watts/ch and still be driven out of the room!

So,
Easy crossovers, because there really is only one on the super tweeter. Addresses the phase and discontinuety issues that people mention about PA speakers. These are basically concentric drivers
so the sound is extremely coherent- read the reviews on the Hammer site.
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Old 8th October 2006, 10:51 PM   #2
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A good idea IMO. For myself, the response doesn't worry me greatly -I've seen much worse from commercial units. A BIB is possible, though it ain't going to be small!. A reverse taper would also be an interesting option. When I'm fully awake I'll look into it.
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Old 8th October 2006, 11:09 PM   #3
Pano is offline Pano  United States
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Hmmm......
Back horn loaded 12" Or is TL? Hmmmm....

As you say, simple and cheap to try. The wood is the most expensive part. And if Punkrokr didn't like it, he could pull it apart, use the wood & Beta 12s in the next project and have a great 12" mid to build on.

Might be worth a shot. Anyone know how to model that big enclosure for the Beta 12LTA?

It would probably sound a lot better than the project I came up with. 4x10" Pyramid clear woofers per side - 2x5" Pyle mids - 1x bullet tweeter. Lights behind the woofers that flash with the music. Maybe not the world's best sounding party speaker - but big, cheap, loud and FUN!
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Old 9th October 2006, 01:04 AM   #4
Variac is offline Variac  United States
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Quote:
nyone know how to model that big enclosure for the Beta 12LTA?
Scottmoose does and he promised to look into it!!!
That web site is Scott's

Also note that he mentioned that it will be big!! Punkr won't mind that!! probably 7' high and 18" wide- that big enough for you?
Almost no crossovers-that solves a big problem.

Tinitus: I don't believe he will need anything other than the 12LTA. The horn really augments the bass to counteract the baffle step that you use a 2.5 to correct usually. As you say the 2.5 is over budget so why do it when this will do the job...

Let's not propose different horn types. This one will work AND scottmoose understands it. If we start going into other types, we are going to discover no one knows how to design one- back to the same problem-people proposing designs they aren't able to implement.

If this works I suspect lots of people will make 'em for party speaks. A cheap way to save your audiophile speakers!!
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Old 9th October 2006, 01:30 AM   #5
tinitus is offline tinitus  Europe
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I have overlooked that Scott will design this horn ....doublehorn??.... if thats the case I think its a very good idea ... backloaded with 12" will have insane bassoutput ... and driver can take a lot of power, unlike small fullrange drivers ....that will be pretty loud

But I would like it more than 18" wide


I grew up with horn building .... so, yes I love the idea
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Old 9th October 2006, 04:18 AM   #6
Variac is offline Variac  United States
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Tinitus , thanks for your support. I really think we can all get behind this. It isn't my design, so that's not why I'm promoting it. I just think it might WORK.

Everyone gets something:

its horn loaded like Cal and tinitus and others like.
It uses the 12LTD that Panomaniac likes,

It's beeeg and insanely loud like Punkrockr always wanted
Punkr- a horn is the way to make the bass from a 12" amazingly loud. Most people don't make 'em because the box will be so big- but you don't mind... You want a single piece big box- this design has to be big and has to be a single box. The box isn't very hard to make either. Also- who would have thought we could make something BASSY and LOUD with that budget?

We have to wait until we see what Scottmoose comes up with, but if he gets it worked out, this will be another part of your dream- it will be a custom design just for you! Sure, I'll bet more people make it later, but you will have the first!!

Best of all it will sound good enough that we audiophiles won't feel guilt.

P.S. Tinitus, I just guessed 18: wide, but seems about what it will be, However it will be deep I'll bet!!

Hey there's an idea: can't the driver be mounted in the "side" of the cabinet? at the same height of course...So the cabinet would be wide and not so deep? I meant , it will be off to one side when looking from the front, to keep it in the horn throat. Then the cabinet would be about 7' tall and 4' wide and 18" deep!! We shouldn't go more than 4' if possible due to the size of a piece of plywood.

I think I need a pair of these for my next big party!



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Old 9th October 2006, 07:27 AM   #7
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Useful speaker design we can use

http://www.fortunecity.com/rivendell...terburner.html


Hammer crossover and info:

http://melhuish.org/audio/super12.html#forum


The Fostex FT17H mentioned is a decent tweeter. I've got a pair.
If Punkr sends me a photo of the finished boxes with the 12" drivers installed I'd give him a great deal.... they are about $35 each mail order.

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Old 9th October 2006, 08:45 AM   #8
Pano is offline Pano  United States
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Ah yes, the "Afterburner" project. Been looking at that one for years.

Problem is, Eminence has changed the Beta 12LTA. The old driver had an X-max of 0.8mm - the new version has about 3mm. Not the same driver anymore. But I doubt this will make any difference to Punkrokr, except that it might be better for him. More volume!

If the Beta12LTA works in a huge TL cab, it could lead to fun things. There are not many 12" fullrange drivers out there, but there are plenty of 10/12/15" coax drivers that might work even better. At a higher cost, of course.
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Old 9th October 2006, 11:21 AM   #9
tinitus is offline tinitus  Europe
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http://www.partsexpress.com/pe/pshow...=264-360&DID=7
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Old 9th October 2006, 01:22 PM   #10
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Hi,

I give up. Its not like he's got a flea powered amplifier and is
not planning to use a subwoofer. In the end reality bites .....

/sreten.
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Old 9th October 2006, 01:38 PM   #11
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Well now, a BIB is on the cards. The site is at www.zillaspeak.com/bib.asp for those interested -Jeff (Godzilla) very kindly offered to host & design the pages, and GM has quite a few of his variations of this cabinet there too.

For those who haven't seen the BIB before, it's a traditional P.G.A.H. Voigt style chamberless corner horn that vents upward -the top is left completely open, and that forms the terminus. The horn mouth is actually formed by the 1/8 space loading of the room; the reflectional boundary conditions creating a virtual mouth 8 times larger than the cabinet terminus. The idea dates back to the 1930s -probably to the late '20s so high tech it is not, but it is very effective.

1/2 space MathCad FR graph attached. Word of warning: this is a big cabinet. Very big. As they're intended for corners this makes life easier, but they're still not small. Most of the ripple you see in the response will be killed by the room, leaving them pretty flat BTW (true -just ask any BIB builder). No worse than a lot of traditional TLs anyway. Add ~6db to the response to account for room-gain. That means theoretically around 100db efficiency for 1watt at 30Hz, and still about 90db at 20Hz.

Cabinet internal dimensions are 16.5in wide, and (wait for it) 23.5in deep. Add 2x and 3x width of your chosen build material to these for external width and depth. Cabinet is 75in tall, roughly 150in path length, driver 30.25in down from the internal top (point above the driver).

Hope you Like Jurassic Park guys.

Enjoy
Scott
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Old 9th October 2006, 06:14 PM   #12
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I used the Beta 8 in a mass loaded transmission line, and I tell you- Martin Kings worksheets seem to work quite well. Further, I believe that a really large box could be configured in such a way to get some unusually good bass out of a pro 12" woofer.

However, a problem I ran into was beaming. Even running the 8" driver to a high crossover point, I noticed a big change in sound as I walked around the room. I expect the 12" to be worse.

It might sound great at the sweet spot, but don't expect a big sweet spot. Also, room treatment could become critical in order to get even bass where the 12"s dictate as the sweet spot.
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Old 9th October 2006, 06:35 PM   #13
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Joe, please keep in mind that the 12" we are discussing has a whizzer cone and is rated as having respnse to 8,000 hz. The small center cone will disperse the higher sound as well as produce it , no?

This particular driver is the key to the idea- it is "full range"- or almost



http://www.partsexpress.com/pe/pshow...90-409&scqty=2


It will still have a cheap, efficient tweeter to get the highest notes.
That tweeter should be rated to go to almost 20k, after all, it only has to cover from 8k up, so a pro driver isn't nevcessary- especially because they don't have the highest top end..
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Old 9th October 2006, 06:41 PM   #14
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Here are some photos Punkrockr, Remember- yours would be more than twice as wide and a lot deeper- with a 12" driver!!The photos show 6" drivers.They don't need to have the tapered stairstep bottom that one photo shows. The standard model is as shown in that photo that shows the interior- two side panels and edges on three sides with the top open and a single diagonal partition in the middle. If you study the site you will see how this creates a horn inside the box. Easy to make ..

http://www.zillaspeak.com/bib-pics.asp
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Old 9th October 2006, 06:44 PM   #15
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16.5in wide internal just ain't bing enought for some folks...
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Old 9th October 2006, 06:49 PM   #16
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Check out this tweeter- its pretty flat from 5k to almost 30k. Really good for Punkr's youthful eardrums! and over 98 dB efficient. As I said I have a pair and they sound decent. Lots of people just love them, and pretty cheap at around $35 each. (cheaper from me if punkr actually DOES something!) The important part is that we have TWO designs that use this tweeter with the same 12LTD driver so we can recommend a decent crossover to Punkr.



http://www.madisound.com/pdf/fostexdrivers/ft17h.pdf
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Old 9th October 2006, 06:52 PM   #17
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Whoops, I missed Scotts' post. Got that Punkr?: 18" wide, two feet deep- no need to turn the cabinet. Also over six feet tall!!!

Those photos are wimpy things compared to this box!

If we can hold the 2' deep dimension, then a sheet of plywood will give you 2 sides.

The other speakers that give us info on the tweeters:
http://melhuish.org/audio/super12.html#forum
http://www.fortunecity.com/rivendell...terburner.html
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Old 9th October 2006, 10:00 PM   #18
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From what I can read the BIB is a compromise by simulating a number of drivers.... from 5" to 8" .... with a fixed length

Are you really sure this will work with a 12"

I am not good in maths ... but dont you get a big change in exstension of the horn when the slanted inner baffle is that much wider in relation to the BIBs with smaller drivers
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Old 10th October 2006, 07:28 AM   #19
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heres a pic of the size Scott mentioned, with a 12" driver and a tweeter below.(could be above...) The woman is 5'-6" tall

Since the speaker puts out almost 100db per watt at one meter, lets say you want 10 times that for dynamics and you probably sit more than a meter from the speakers..- That means a 20 watt per channel receiver you can pick up for $25 at Goodwill would blast you out of the house. Especially considerig that you would have TWO speakers!

How come other speakers need hundreds of watts?
Well a lot of people actually find large speakers to be a problem, not a cool thing, and smaller boxes are generally less efficient. Luckily you don't have that problem- maybe Also these are horns, or transmission lines or somethin' with a pretty much full range driver.
Some love 'em some don't. I don't think you are so picky that it would matter.. They will have lots of bass and lots of volume and probably sound pretty cool indeed.
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Old 10th October 2006, 07:46 AM   #20
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Cool drawing, Mr. V. Not as huge as I had imagined them.
But I think the little girl is scared.

What are we looking at - 4 or 5 sheets of Ply/MDF?


Wonder if I could talk my wife into letting those into the living room - if they were real pretty....
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Old 10th October 2006, 08:42 AM   #21
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At home I use a 6 1/2 inch woofer in my folded voigt style speakers, only 4 foot tall, length of line is 7 ft. sounds great, the midbass is far superior to ported designs, and people cannot believe the amount of subbass that comes from them, people are always looking for the seperate sub bass unit that does not exist. I am very interested to hear how awsome the results will be with a 12". Wow interesting plan
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Old 10th October 2006, 12:14 PM   #22
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I'm ready
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Old 10th October 2006, 01:16 PM   #23
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Quote:
Originally posted by punkrokr1701
I'm ready
There is your birthday present then.

Plug in that table saw and put in the ear plugs.
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Old 10th October 2006, 01:31 PM   #24
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Quote:
Originally posted by tinitus
From what I can read the BIB is a compromise by simulating a number of drivers.... from 5" to 8" .... with a fixed length

Are you really sure this will work with a 12"

I am not good in maths ... but dont you get a big change in exstension of the horn when the slanted inner baffle is that much wider in relation to the BIBs with smaller drivers
Good questions. Answering them in order:

No. I occasionally restrict line-length with low Fs drivers to keep cabinet height, and driver position to reasonable levels. In a BIB, horn length is determined by 1/2 the wavelength of the tuning frequency. Usually this is set to Fs, or just below, but if you've a low Fs driver things can get out of hand, so I tune a bit higher. FWIW, I've built a pair with the Fostex FF225K for a friend before now, which were 89in tall, approximately 178in line length to math their 38Hz Fs. Sound was -er, rather impressive. Like my FF165K boxes, but larger. In this case, we've a 45Hz Fs, which equates to a half-wavelength of roughly 150in.

Oh yes indeed. Of course it will work with a 12in driver. The physics doesn't change just because it's got a hefty cone area. Higher Vas & Qt simply require a larger box (cone-area per se has little to do with it).

No. Vb needs to swamp, or come close to swamping, the driver's Vas. Width and depth dimensions are usually selected to preserve the conical horn profile (depth needs to be 1.414 times width) though there is plenty of room for experiment here. Terry Cain's original cabinet had a 1:2.2 ratio for example. So long as CSA is preserved, you can try different things out. The internal baffle terminates in the centre of the cabinet, the same distance from the floor as from the internal front and rear walls.

The point above the driver needs a light layer of stuffing, and a nice thick carpet of the stuff on the internal base will absorb any stray HF and damp out reflections. Beyond that, stuff to taste once in-room. Because they use the room as part of the speaker, they all need somewhat different quantities, though most of the time, the above is all that you'll find necessary.

Deflector panels are a bad idea BTW guys -the bass we want couldn't care less if a corner is smooth or not, but the unwanted HF does. So abrupt is the order of the day.

Doesn't sound too scientific I know, but it works. The more we learn, the more we forget. These simple, traditional corner horns are as effective now as they ever were. 3 watts into these will blow your windows out. And they do dynamics like little else you will ever hear from full range, or wide-range, drivers.
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Old 10th October 2006, 06:35 PM   #25
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Quote:
Originally posted by punkrokr1701
I'm ready

Miracle!!! We are all in agreement- or as close as is possible for this group. Punkrockr- I really think these will do it for you. It is amazing that you will get your wish at about a quarter of the budget we had gotten up to! The only expense is the 12" driver at this time, and a lot of plywood or MDF.

http://www.partsexpress.com/pe/pshow...90-409&scqty=2

I got their actual price and it's $58 each. So for under $150 including shipping you will have all you need to get started. You can add the tweeter later, after the cabinets are finished and even after you have tried them with just the 12" at first if you want..

If the cost of plywood is too much you CAN use MDF (medium density fiberboard) . MDF is available in lumber yards and Home Depot type places. It is like a very dense particle board (DON"T use particle board!) The good thing about it is that it is only about $25 a sheet in 3/4" thickness. The bad things are: It is very heavy. Each speaker will use about two and a half sheets minimum so you and your dad should try picking up two sheets together in the store and decide if you can or want to carry a speaker of more than that weight, plus the driver weight.. The other bad thing is that it isn't anyways near as strong as plywood, so if you move the speakers much the corners will be damaged and worse. Of course at that weight, you probably won't be moving them much, unless you are thrown out of your house because the police keep coming due to neighbors reporting too loud music.....

Many people prefer the sound of Plywood in this use, but the differences are sure to be subtle enough to not matter to you. Still plywood is the best choice, and I found someting called "imported birch" at about $40 a sheet which worked very well for my big home speakers. So check different places...

Seems like you will need six sheets....
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