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Eminence LAB 12 Sub(s) ?


HPower

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1 hour ago, jason str said:

The room and placement will dictate frequency response unless the room is a warehouse or outdoors.

It turns out that the size of the mouth of the horn (total area) is a pretty good predictor of how much boundary gain that you CAN get.  But, as I've noticed, many users don't position their horns in-room to take advantage of this. 

 

One example: the K-402-MEH.  It has a mouth area that exceeds the Jubilee bass bin and the Khorn bass bin (two mouths each, BTW), but the K-402 picks up boundary gain like no other loudspeaker that I've experienced (making it the best "corner horn" that I own).  Below you will see extracted from Bruce Edgar's paper on tractrix horns the relative bass bin mouth size cutoffs...assuming that all four bass bins have tractrix mouths (which they don't--only the K-402 has a tractrix mouth, the others have exponential mouths with more pronounced low frequency cutoffs):

 

1350258416_Tractrixcornerloading.thumb.JPG.1c8d7924c63d792ccf8a43edff74da50.JPG

 

Accordingly, the K-402-MEH picks up boundary gain much more readily than do the other bass bins--more than 12 dB in practice relative to mid-wall loading.  The same principle holds true for subwoofers--the bigger the horn mouth, the more they pick up boundary gain, but only if placed fully in the room corner to pick up that gain.  (The TH-Spud has a severely undersized mouth that doesn't pick up boundary gain very easily, but it doesn't matter since the horn itself has a internal resonant frequency of 14 Hz due to the length of the internal horn--regardless of being in boundary gain or not.)

 

This is where the BFM subwoofers can excel, i.e., they tend to have larger mouths. But only if they are placed in-room to pick up that boundary gain, namely with their mouths fully in the room corner.  In the case of BFM horns--they must actually be aimed into the corner due to their form factor dictating that orientation in order to fully pick up boundary gain.  The K-402-MEH easily fits in a room corner, so it easily picks up almost an octave and a half of boundary gain while facing forward, while the other bass bins pick up lesser amounts of boundary gain in a corner orientation.

 

Chris

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26 minutes ago, Chris A said:

It turns out that the size of the mouth of the horn (total area) is a pretty good predictor of how much boundary gain that you CAN get.  But, as I've noticed, many users don't position their horns in-room to take advantage of this. 

 

One example: the K-402-MEH.  It has a mouth area that exceeds the Jubilee bass bin and the Khorn bass bin (two mouths each, BTW), but the K-402 picks up boundary gain like no other loudspeaker that I've experienced (making it the best "corner horn" that I own).  Below you will see extracted from Bruce Edgar's paper on tractrix horns the relative bass bin mouth size cutoffs...assuming that all four bass bins have tractrix mouths (which they don't--only the K-402 has a tractrix mouth, the others have exponential mouths with more pronounced low frequency cutoffs):

 

1350258416_Tractrixcornerloading.thumb.JPG.1c8d7924c63d792ccf8a43edff74da50.JPG

 

Accordingly, the K-402-MEH picks up boundary gain much more readily than do the other bass bins--more than 12 dB in practice relative to mid-wall loading.  The same principle holds true for subwoofers--the bigger the horn mouth, the more they pick up boundary gain, but only if placed fully in the room corner to pick up that gain.  (The TH-Spud has a severely undersized mouth that doesn't pick up boundary gain very easily, but it doesn't matter since the horn itself has a internal resonant frequency of 14 Hz due to the length of the internal horn--regardless of being in boundary gain or not.)

 

This is where the BFM subwoofers can excel, i.e., they tend to have larger mouths. But only if they are placed in-room to pick up that boundary gain, namely with their mouths fully in the room corner.  In the case of BFM horns--they must actually be aimed into the corner due to their form factor dictating that orientation in order to fully pick up boundary gain.  The K-402-MEH easily fits in a room corner, so it easily picks up almost an octave and a half of boundary gain while facing forward, while the other bass bins pick up lesser amounts of boundary gain in a corner orientation.

 

Chris

 

Mutual coupling is another benefit that arrives with horn loading (excluding tapped horns), multiple horns will play lower where their opposition does not.

 

You don't need corners for this.

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7 hours ago, jason str said:

My THTLP is -3 dB @ 18 Hz in 16'x 24'room.

With the LAB 12 driver? or the original recommended one? I used to get response down to 15 Hz. with the LAB12 TH the Ruler flat portion was miked at the mouth, so no room interaction there, ruler flat from 20-60

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12 hours ago, Chris A said:

Room boundary gain is free (to quote PWK).  Adding more bass drivers/horns isn't.

 

Chris

Actually, the room is the most expensive component, and it's far from "free." This is a misnomer at best. However, you can't leave a speaker outside, so it has to be in a room somewhere. LOL.

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12 hours ago, HPower said:

Thanks guys for the suggestions so far!

 

I agree that the Tuba 60(s) would be killer subs, but the size of these B#ggers might be an issue for my room.

And my room is in the basement, which is a chore to lug big boxes down into.

My F20 was a struggle and then my Jub clones were a real B!t@h to get up and down the stairs, even with four guys!

 

Claude's plans look to be much more manageable to build and transport to the basement.

The multiple sub technique is also what Wayne Parham endorses, hence why I original thought of going with 4 of his 3Pi subs.

 

 

 

That sub is the easiest thing I ever built because it's all RIP cuts, except for the 30x60 pieces.

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12 hours ago, HPower said:

My memory is not what it should be, sucks getting old, but was the Spud and or Super Spud built around the LAB12 driver?

I did a google search, but I did not come up with plans for either of those.

 

I have built 5 spuds total, and have owned two Danley Super Spuds (DTS-10's). I had to replace one of the drivers in the Super Spud. It's a beefed up LAB12, but can only be purchased from Danley and it's pricey. Stick with what you have. An additional $400 in lumber should do the trick and you will have some killer subwoofage against 4 walls. Then they will be called "wall subs" instead of "coffee table subs" like mine was. LOL.

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20 hours ago, HPower said:

Claude's plans look to be much more manageable to build and transport to the basement.

The multiple sub technique is also what Wayne Parham endorses,

In my case, I just ran the wire direct to the driver through the mouth. In the upright photo (not mine) it shows the wire running very long inside the box and a trap door. I would NOT do this. In fact, there plenty of room in the "dead space" to have a recessed connector of your choice, dilling and sealing a wire hole near the mouth and running a short wire to the driver. The simpler, the better.

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Hey Claude,

 

Not sure how well you remember my basement room, but at 15'x20' I think I could probably shoehorn four of the designs you suggest into the room.

With my current F20, I have it running with a Crown XLS1500 bridged and crossover'd around 60 along side my FH1s / K402s.

The Peavey / 402s are xover'd via my Xilica XP4080, thanks to Chris A's guidance and setup.

 

What do you think might be the best way to Xover and power 4 of these subs in my room?

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9 minutes ago, HPower said:

Hey Claude,

 

Not sure how well you remember my basement room, but at 15'x20' I think I could probably shoehorn for of the designs you suggest into the room.

With my current F20, I have it running with a Crown XLS1500 bridged and crossover'd around 60 along side my FH1s / K402s.

The Peavey / 402s are xover'd via my Xilica XP4080, thanks to Chris A's guidance and setup.

 

What do you think might be the best way to Xover and power 4 of these subs in my room?

4th order bandpass from 20-60 Hz. These subs are about 95 db sensitive at 6 ohms, so not very demanding of power like direct radiator subs are. I'm surprised you use so much power on an F-20, but headroom is fine, eh?

 

Get some cheap Behringer class D's with built in crosovers, I think they make a quad version.  Any complementary time delays you may need to use are best used from you Xilica on your FH-1/K402 combo.  BTW, I'm about to do the same in my basement, with either your old Faital Drivers or go 3 way with Klipsch K1133 and DaveA Large MAHL/DE-10 drivers. I'm glad you like the FH-1's. I used to call them "cheap Scalas" but they are actually superior in every way. Send me a photo, if you have one.

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I am running the Peaveys as 2-way with the K402, the K510s in the centre top hat are not being used right now.

The F20 is is to the left of where this pic was taken.

For the F20, I have the XLS1500 being feed from the Wyred 4 Sound preamp's extra XLR output, using the Crown's Xover, not the Xilica.

 

I am guessing the best way would be to use one of the remaining open XP4080 outputs to run the sub amp(s)

 

You may notice, on top of the HIP,  you will see a Crown D75A.

I have a 2nd one sitting on the shelf, but I doubt these 2 would have enough power to drive the 4 LAB12 subs?

Could probably pick up a 2nd XLR1500 for a couple hundred bucks on FeaBay.

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15 hours ago, ClaudeJ1 said:

With the LAB 12 driver? or the original recommended one? I used to get response down to 15 Hz. with the LAB12 TH the Ruler flat portion was miked at the mouth, so no room interaction there, ruler flat from 20-60

 

The Eminence LAB 12 falls within specification for any of the previously mentioned models.

 

My measurements were taken @ main listening position using a 15" loaded 21" wide inverted THTLP.

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