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Discussion Starter #1
Hornloaded will squish both...(provided you're serious about building a proper horn) ;)
 

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Re: IB or LLT

Hornloaded will squish both...(provided you're serious about building a proper horn) ;)
In my experience horns roll off way too high. How low are you talking of a 3db downpoint? Ive always been interested in horn designs.
 

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Discussion Starter #4 (Edited)
Re: IB or LLT

In my experience horns roll off way too high. How low are you talking of a 3db downpoint? Ive always been interested in horn designs.
10Hz low enough for ya? What about 135dB at 10Hz from a single 12" driver?
 

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Re: IB or LLT

10Hz low enough for ya? What about 135dB at 10Hz from a single 12" driver?
Uh... yeah... enlighten us all. :bigsmile: I think we all know this is not possible with a reasonably sized cab/horn in normal listening environments. If it is and you have come across some "new" discovery, then let's start a new thread and I am sure it will be the "hit" of the forum.

I am sure we all remember the horn that reached 10Hz...

 

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Re: IB or LLT

10Hz low enough for ya? What about 135dB at 10Hz from a single 12" driver?
Care to explain this...I'll build 4 and so would everyone else. Hence it is impractical, impossible, or otherwise unattainable. This thing would make every other bass enclosure and driver whether, HT, car audio, Proaudio, cinema, or whatever, obsolete.

Not even Tom Danley with an uber 12" engineered specifically for this horn could make that happen in any realistic scenario short of the mic actually in the horn mouth.

Even a TH for 10hz response with a 12" is huge. A "real" 10hz horn for a 12" will be gigantic and it will not come close to hitting 135db at 10hz in any meaningful way. Look at the size of the THspud for "only" an 18hz response and no where close to 135db.
 

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Discussion Starter #9 (Edited)
Re: IB or LLT

AE AV12X, 8Hz flare tractrix horn truncated to 1800cm in length. Like I said, you need to be serious about building a proper horn....now before this is ruled out as totally impractical, there's a lot of space available in an attic that is normally being used as the rear wave of the IB. The total system volume for this is 1000 cubic feet, which with efficient folding could fit in a 10x10x10 box...

The grey line at the bottom is the response with 1W of input....the black line is the maximum SPL limited by cone excursion at the lower frequencies and power handling at the higher frequencies.
untitled.JPG

Also, unless your IB is outdoors, the acoustic space behind the driver is just a really large sealed enclosure. You will suffer from the same modal response issues that you have in your own listening room.
 

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Discussion Starter #10
Re: IB or LLT

Now for one that I might build....

Four AE AV12X drivers in an offset horn. Flare rate of 15Hz truncated to 18ft with a 16ft mouth. 100V into a series parallel arrangement will yield an easy 145dB down to 20Hz. Total volume comes to around 100 cubic feet.

untitled.JPG

You can make things even smaller if you want to account for the extra loading the corner of the room will offer....or just let the room loading extend the response down an extra octave or so ;)
 

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Re: IB or LLT

AE AV12X, 8Hz flare tractrix horn truncated to 1800cm in length. Like I said, you need to be serious about building a proper horn....now before this is ruled out as totally impractical, there's a lot of space available in an attic that is normally being used as the rear wave of the IB. The total system volume for this is 1000 cubic feet, which with efficient folding could fit in a 10x10x10 box...
So ...it's not impractical, impossible, or otherwise unattainable. 137db @ 16hz ...u would be the new 'Basspig' :hail:
 

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Re: IB or LLT

1000cu ft.:sneeky: C'mon now Mike. I like a good horn too and I'll give them their due, but that's just not going to work for most people. 1000cu ft is a small room. Honestly I still don't believe it'll hit that 135db at 10hz without driver disintegration no matter what HR says. The input power is listed at 1000w but the graph shows well more than 30db of gain in some areas and the sensitivity at 10hz is like 113.5 db? Is this possible? I can't think of a single product on the market with that kind of sensitivity below 100hz. Also is this graph for half space, quarter space or what?

If you can picture how big a 25 cu ft EBS ported cab is, it's absolutely huge. We are talking about the space of 35 of those conservatively. If this kind of performance is easily attainable with a good $300 medium duty 12" driver and $700 worth of wood, why aren't IMAX's,theaters and amusement parks using big horns like this for subwoofers? They'd save thousands of dollars and have higher performance.
 

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Re: IB or LLT

Now for one that I might build....

Four AE AV12X drivers in an offset horn. Flare rate of 15Hz truncated to 18ft with a 16ft mouth. 100V into a series parallel arrangement will yield an easy 145dB down to 20Hz. Total volume comes to around 100 cubic feet.

View attachment 13205

You can make things even smaller if you want to account for the extra loading the corner of the room will offer....or just let the room loading extend the response down an extra octave or so ;)

Interesting. Even with the response dropping off at 22 hz it still shows 135 db at 18 hz. Could you post a drawing of the the box shape and horn path so I can visualize this?
 

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Discussion Starter #14
Re: IB or LLT

1000cu ft.:sneeky: C'mon now Mike. I like a good horn too and I'll give them their due, but that's just not going to work for most people. 1000cu ft is a small room.
It all just comes down to how serious you are....one of the attics posted in this thread could easily fit such an obnoxious horn in it.

Honestly I still don't believe it'll hit that 135db at 10hz without driver disintegration no matter what HR says. The input power is listed at 1000w but the graph shows well more than 30db of gain in some areas and the sensitivity at 10hz is like 113.5 db? Is this possible? I can't think of a single product on the market with that kind of sensitivity below 100hz. Also is this graph for half space, quarter space or what?
For starters, this is predicted in 1/8 space, so you get an extra 6dB compared to half-space right off the bat.

Secondly, these horns are showing a 1:1 compression ratio, which means there shouldn't be any throat overload (since the driver can already achieve that velocity).

And third, everyone always thinks that low frequencies contain more energy than higher frequencies...which is absolutely the opposite. The thing about frequency and acoustics is that it just scales with wavelength....low frequency have big wavelengths so you need big horns. The point I'm trying to make is there are high frequency compression drivers that are pushing 140dB with 8:1 compression ratios...of course they're using stiffer materials than aluminum for the diaphragm, but I don't think the aluminum is that far off.

And finally, I see 113.5dB as a huge waste in power...that's like only 10% efficiency :O

If you can picture how big a 25 cu ft EBS ported cab is, it's absolutely huge. We are talking about the space of 35 of those conservatively. If this kind of performance is easily attainable with a good $300 medium duty 12" driver and $700 worth of wood, why aren't IMAX's,theaters and amusement parks using big horns like this for subwoofers? They'd save thousands of dollars and have higher performance.
Because most of those environments have very strict limitations to the depth of the enclosure. And if you want any control of your polars in such a situation (which you do), then going direct radiating is the only option. In cases where depth isn't a limitation, then I agree....what the are they thinking?

I am only making the recommendation because I see big empty unused spaces. I also offered the 100cu ft option because it's incredibly more practical. I just posted the 1000cu ft option to demonstrate that 10Hz reproduction in indeed obtainable with a horn. Also, I believe there's a crazy dude in Florida that will be building a horn on the order of this magnitude...

Also, if you're worried about cone stiffness, then just double up on drivers and spread the load.
 

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Discussion Starter #15
Re: IB or LLT

Ok, how about this more sane option?

Horn length is 17ft long, 1.5ft deep. The mouth is 8ft x 1ft....just large enough to cut out all the drywall in the corner of your room.

Here's a drawing for it to make more sense:
untitled.JPG

And then here's the predicted response using the corner of the room as the rest of the flare of the horn:
untitled2.JPG

Four AE AV12X drivers are gonna run $800. I'm not sure how much the wood would cost, but let's just call it another $1000. Throw in a QSC PLX3602 for $1500 and now you're looking at a total system cost of around $3500? How much for an LMS5400 again? ;)

Here's the max response one might expect:
untitled3.JPG

Btw, these simulations are conservative and assuming a room that is about 16x24. And even if you didn't want to cut holes in your front wall, with an 18" depth you can just make your room a little bit smaller. Also, there's no reason why the horn couldn't be folded and two put in a single room. That'll give you yet another 6dB.

So why don't people do horns? I have no clue.
 

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I've seen so few large scale bass horns! I'll never have one, but I'd love to see pics of some! Or even a youtube vid of one...lol. DrWho I hope you build one for us to see, as I am an incurable bass fanatic.
 

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Mike,

I still think that those graphs are a bit optomistic. That's neither here nor there though. I don't dispute that horns can perform, we all know that they can, but when you are talking about 100 to 1000cu ft enclosures that need to be carefully engineered and folded up into the size of a room and then somehow constructed inside the home or attic with a mouth that's anywhere from 8sq ft to the size of half of the wall incorporated as well, it's getting a bit impractical for my taste. The logistics are a nightmare. Plus if you ever move you have to leave it. What if you need to access, service, or otherwise use your attic? Then there's the whole issue of how the horn is going to respond in the room itself. It's not like you can move it.

If I was building a theater from the ground up I'd probably go this route.

I'll take a couple of LMS5400's in 22" sealed cubes any day. :yes: Besides who says you can't hornload a couple of those anyway? :whistling: I've actually toyed with the idea momentarily but it's just too involved.
 
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