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Author Topic: Lab Sub help  (Read 2423 times)

Ivan Beaver

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Re: Lab Sub help
« Reply #10 on: February 21, 2018, 11:50:20 am »

Maybe the guy was really precocious.....I mean, he sort of invented a "tapped (lab)horn"  ;D
Simply having the drivers other side exposed to the outside is NOT a tapped horn.

The details are how the sound from the other side of the driver will also load the horn.

Here is a link to the "basic operation" of the tapped horn

http://www.danleysoundlabs.com/danley/wp-content/uploads/2012/01/The-Tapped-Horn.pdf

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Mark Wilkinson

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Re: Lab Sub help
« Reply #11 on: February 21, 2018, 11:55:41 am »

Simply having the drivers other side exposed to the outside is NOT a tapped horn.

The details are how the sound from the other side of the driver will also load the horn.

Here is a link to the "basic operation" of the tapped horn

http://www.danleysoundlabs.com/danley/wp-content/uploads/2012/01/The-Tapped-Horn.pdf

Joking brother !!!
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Tim McCulloch

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Re: Lab Sub help
« Reply #12 on: February 21, 2018, 12:27:59 pm »

That is funny !!!
Some guy actually built labhorns with NO rear covers  ?  Wow.. and they still made OK sound...wow..

Who knows what impedance that made.... at any freq...could have been near toaster oven Rdc, thru whole range lol...or not?

I really don't know what to make about labhorns vs today's offerings.
I built 4 by the original plans, pretty carefully. 
When i test them against the modern subs I have, orbitshifters, and a pair of DIY BMS 18"s,  it's hard not to give the labsubs the nod.  Against the OS, Labs are 3db more efficient, have smoother response, and go a little lower. But the OS does handle at least twice the power. Against the BMS 18"s, the labs are more efficient, but otherwise the pair of BMS rules.
Then I look at another highely regarded alternative, the TH-118. Doesn't seem any more efficient than the labsub, however, like the OS, it handles twice the power.  But phase is mixed up...inherent to tapped horns I think...

I've heard about the heating/compression problem with labhorns, but i didn't see any of that on a handful of gigs with them last summer. 
Maybe folks either pound them past reason, cause they stay clean sounding, or use a too high a freq low pass filter. Impedance says they will burn up quicker used over 95Hz than below I think.....
I wish i could get a true read on the heating prob, if there is one...


Because I'm in the middle of re-plotting subs.  Just built a boatload of mid-high capability, and need to build/buy subs to catch up.

I might actually end up building more labhorns,

 ...or building some DIY TH's or keystones,...or building more of the single BMS 18" BR's I that i REALLY like, .....or maybe even  buying TH-118s or OS's for resale value.
 
I need to get to at least an 8-10 labsub rig...will  restart from scratch if need be..damnit :)

I think you are close.  The LABhorn doesn't sound distressed until right before it dies and most users don't notice the power compression that is the indication you're out of gas.  Some users turned it up more until either the cone came apart or the voice coil burned up.  We've had limiter setting discussions re: the LABhorn in the past.

The LABs don't sound particularly good above 80Hz to me and I'd pick that has my LPF point to start with.

That Tom D's design holds up nicely after 15 years is a very good thing and shows how incremental improvements to performance can be.
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Mark Wilkinson

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Re: Lab Sub help
« Reply #13 on: February 21, 2018, 03:21:25 pm »

I think you are close.  The LABhorn doesn't sound distressed until right before it dies and most users don't notice the power compression that is the indication you're out of gas.  Some users turned it up more until either the cone came apart or the voice coil burned up.  We've had limiter setting discussions re: the LABhorn in the past.

The LABs don't sound particularly good above 80Hz to me and I'd pick that has my LPF point to start with.

That Tom D's design holds up nicely after 15 years is a very good thing and shows how incremental improvements to performance can be.

Yeah, it's pretty cool the design has held up for so long.

I have to agree about their sound, I've always low passed them at 77-80Hz when I could.
In fact, thanks for mentioning that....I'd kinda forgot that.  Knocks them out of contention for increasing the sub herd.....
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Tim McCulloch

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Re: Lab Sub help
« Reply #14 on: February 21, 2018, 04:48:21 pm »

Yeah, it's pretty cool the design has held up for so long.

I have to agree about their sound, I've always low passed them at 77-80Hz when I could.
In fact, thanks for mentioning that....I'd kinda forgot that.  Knocks them out of contention for increasing the sub herd.....

As haystacked as subs are the acoustic crossover may be a half octave higher.  There are front loaded subs that have a high second harmonic content around 100-150Hz that do not seem to attract attention.  If you're already invested in the LABhorns I see no reason to abandon them.
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"Practicing an art, no matter how well or badly, is a way to make your soul grow, for heaven's sake. Sing in the shower. Dance to the radio. Tell stories. Write a poem to a friend, even a lousy poem. Do it as well as you possible can. You will get an enormous reward. You will have created something."  - Kurt Vonnegut
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