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Author Topic: What amp are you using to power your LABhorn?  (Read 19580 times)

Alan Star

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Re: What amp are you using to power your LABhorn?
« Reply #20 on: December 07, 2006, 10:15:35 pm »

Kit Hannah wrote on Thu, 07 December 2006 07:59

Alan Star wrote on Thu, 23 November 2006 01:18

Crown iTech 6000

I run 2 labhorns per channel in parallel.

It may be interesting to note that on the front display of the iTech the monitor feature shows a loading of 3 ohms per channel in the above configuration. Sometimes it will flash to 2 but mostly says 3... for what it's worth.

If I could afford another iTech I think i would get another and run one box per channel.




Maybe the amp is showing 3 ohms because you have 2x 6 ohm labs run in parallel? Just a thought...


Well actually...no...because if you read my post you will see that i am running 2 labhorns on each channel and each labhorn has 2 6ohm drivers...so actually thats 4x 6ohm drivers in parallel on each channel which is why I find it interesting that the itech sees a 3ohm load on each channel ? Sometimes it will flicker down to 2 ohms...I wonder how accurate it is ?
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Mac Kerr

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Re: What amp are you using to power your LABhorn?
« Reply #21 on: December 07, 2006, 10:26:58 pm »

Six ohms is the rated impedance of each LAB driver, not the absolute impedance. Is there an impedance curve of the driver anywhere so we could see what the actual impedance is at what frequencies?

Mac
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Sean Tan

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Re: What amp are you using to power your LABhorn?
« Reply #22 on: December 17, 2006, 12:05:48 am »

Hi all,

Been lurking around here for quite a while, planning to build a couple of Labs next year.

One thing thats been bothering me is how to go about powering them. Many people report bridging one amp per LABsub, with good results. To my understanding, one Lab has two 6ohm drivers wired in parallel, presenting the amp with a 3ohm load, nominally rated.

My question is, if the amp is running a 3ohm load while bridged, wouldn't each channel "see" half that impedance (1.5ohms)?  Correct me if I'm wrong, but isnt that load below what most amplifiers are designed to drive?

Cheers
Sean
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Tom Herr

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Re: What amp are you using to power your LABhorn?
« Reply #23 on: December 18, 2006, 06:22:23 am »

The ohms load is frequency dependant. If you look at the ohms accross the full frequency range these are covering you will see that is is actually a bit higher. The labhorn properly built with lab12 drivers is actually closer to the equivalent of any other 4 ohm box you would purchase.
As for the amps I have powered mine with QSC, RMX and PLX's Bridged one per lab with no problems. I think you will find many others here who have had similar experiences with various amps.

Hope this helps.
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Tom Herr
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sheldon harris

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Re: What amp are you using to power your LABhorn?
« Reply #24 on: December 26, 2006, 10:07:55 am »

Sean Tan wrote on Sun, 17 December 2006 01:05

Hi all,

Been lurking around here for quite a while, planning to build a couple of Labs next year.

One thing thats been bothering me is how to go about powering them. Many people report bridging one amp per LABsub, with good results. To my understanding, one Lab has two 6ohm drivers wired in parallel, presenting the amp with a 3ohm load, nominally rated.

My question is, if the amp is running a 3ohm load while bridged, wouldn't each channel "see" half that impedance (1.5ohms)?  Correct me if I'm wrong, but isnt that load below what most amplifiers are designed to drive?

Cheers
Sean


the amplifiers would not see 1.5 ohm unless the cabinet is driven below its cutoff frequency. even if driven below F3, the impedance might be lower or higher than 3 ohms, and is frequency dependent.the reason why people are bridging amplifiers per labs is that:

a properly designed horn loaded enclosure, will load the drivers, so that they typically exhibit(amplifier sees) an impedance of 1.5 to 2 times the nominal impedance. example:
a 4 ohm speaker in a properly designed horn enclosure would behave as if its a 6- 8 ohm speaker. this is the tricky part, the dc resistance is not changed by the horn's loading, and the rule only applies, if the driver/horn is driven in its passband above cutoff frequency. if the horn driver/horn is driven with frequencies near or approaching F3 that phenomenon begins to change slightly as excursion increases and the horn more and more begins to lose control of the cone. below F3, the loading has been lost and the driver will revert back to its original impedance because there would be no horn loading.

I'm pretty sure someone else can add to what i have said, when it comes to horn technology this site has quite a few members who are the "authority" so to speak.

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jeffhtg (Jeff Kenney)

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MA5000 / RMX4050
« Reply #25 on: November 03, 2008, 10:17:00 pm »

So I've been running 8 labs for few years now. inner 4 of 8 running off 2 macro vz5000's (1 per side, stereo).. there is a huge difference in output between the outer boxes and inner boxes. I've also blown the occasion speaker on the outer boxes. This could be due to air leak - or could be also be voice-coil bottoming out (coil edge seemed to have flatted a tad - but not much on 2 of the drivers). These amps run almost all the way up to clip - very light limiting. Have yet to blow a driver on a VZ powered lab.

I'm pulling all cabinets this winter to inspect them carefully - seal any holes I find and play with powering them a little more.. My thoughts are that the the subs could use a little more power and the cheaper RMX amps are just not providing the same control that the VZ's are. (even though I usually like QSC over Crown for audio quality)
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Mac Kerr

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Re: MA5000 / RMX4050
« Reply #26 on: November 04, 2008, 09:41:41 am »

jeffhtg (Jeff Kenney) wrote on Mon, 03 November 2008 22:17

So I've been running 8 labs for few years now.

If you have been running these for a few years now, why didn't you answer this question in April of 2004 when it got asked? Even the recycling of this question was 2 years ago. Why dredge it up a third time?

Mac
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jeffhtg (Jeff Kenney)

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Re: MA5000 / RMX4050
« Reply #27 on: November 05, 2008, 08:48:14 pm »

Mac Kerr wrote on Tue, 04 November 2008 14:41

jeffhtg (Jeff Kenney) wrote on Mon, 03 November 2008 22:17

So I've been running 8 labs for few years now.

If you have been running these for a few years now, why didn't you answer this question in April of 2004 when it got asked? Even the recycling of this question was 2 years ago. Why dredge it up a third time?

Mac


slow news day mac..
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Dave Yorke

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Re: What amp are you using to power your LABhorn?
« Reply #28 on: September 23, 2009, 09:53:13 am »

FFA 8.0 - 2 labs per channel. sounds bloody amazing...  lightweight and clear. we own 8 subs in all but i need another amp.

so far no problems with the subs, due to limiting.
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Silas Pradetto

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Re: What amp are you using to power your LABhorn?
« Reply #29 on: September 24, 2009, 05:37:54 pm »

Dave Yorke wrote on Wed, 23 September 2009 09:53

FFA 8.0 - 2 labs per channel. sounds bloody amazing...  lightweight and clear. we own 8 subs in all but i need another amp.

so far no problems with the subs, due to limiting.


Prepare for Mac's wrath...
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