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Author Topic: Lab Sub handling  (Read 18048 times)

Art Welter

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Re: Lab Sub handling
« Reply #20 on: November 22, 2013, 10:24:14 am »

1)Isn't a limiter that you set max voltage in Vp going to limit peaks?

2)The nu 3000 DSP in stereo mode is already hard capped out and limited at 82Vp or so, which is just under 1700 Watts peak at 2 ohms.  So isn't that an appropriate default setting to use if the HPF is on and I'm only playing properly mastered music myself (no live bands or live synth producers)? 

3)What Vp setting would you use if there was no HPF and they were just reproducing a movie through them when they're not out?
1) Yes, peak limiters limit peaks, not average. The average level could be near the peak level until voltage limiting kicks in, which it will fairly quickly with an iNuke, since it must voltage limit to keep from blowing a 15/20 amp circuit.

2) 82v x 82v=6724/2.25=2988 watts, about 1500 watts per driver.

3) I would not use LabHorns without a HPF.
I have not used an iNuke 3000 DSP, nor am I familiar with it's output or DSP capabilities, so have no further advice for you.

Read the manual and use the advice from prior posts.
Don't worry, be happy  :).

Art
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Ivan Beaver

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Re: Lab Sub handling
« Reply #21 on: November 22, 2013, 11:54:55 am »



3) I would not use LabHorns without a HPF.

I would argue that EVERY speaker needs a high pass filter.
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Ivan Beaver
Danley Sound Labs

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Benjamin Goulart

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Re: Lab Sub handling
« Reply #22 on: November 23, 2013, 02:49:49 am »

I would argue that EVERY speaker needs a high pass filter.

I thought I read Danley state that using the Labhorn for very deep bass was perfectly safe at low volumes and didn't produce more distortion in the very low end than a reflex design.  He said you just need to worry about boosting the very deep bass and remembering that any EQ settings are boosting the voltage going to the drivers in that band.  I believe someone was talking about a crazy home theater setup.  He didn't give a specific voltage limit, though.  I was just messing around with them and didn't find 5-10V limits with no HPF was particularly messed up or distorted sounding.  Drivers sounded well-behaved, I just didn't think it was incredibly clean sounding and got nervous about sending more into them.
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Ivan Beaver

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Re: Lab Sub handling
« Reply #23 on: November 23, 2013, 09:33:34 am »

I thought I read Danley state that using the Labhorn for very deep bass was perfectly safe at low volumes and didn't produce more distortion in the very low end than a reflex design.  He said you just need to worry about boosting the very deep bass and remembering that any EQ settings are boosting the voltage going to the drivers in that band.  I believe someone was talking about a crazy home theater setup.  He didn't give a specific voltage limit, though.  I was just messing around with them and didn't find 5-10V limits with no HPF was particularly messed up or distorted sounding.  Drivers sounded well-behaved, I just didn't think it was incredibly clean sounding and got nervous about sending more into them.
You can run any speaker below its rated low freq response-AS LONG AS the levels are below max output.  The lower the level-the low you can run it or add boosting down low.  So it is a "sliding scale".

I would however make the argument that this is not the "intended usage" of the cabinet-and that you should use a highpass for the INTENDED usage of a cabinet.  I guess I did not make that clean
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Ivan Beaver
Danley Sound Labs

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Benjamin Goulart

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Re: Lab Sub handling
« Reply #24 on: November 23, 2013, 12:48:59 pm »

You can run any speaker below its rated low freq response-AS LONG AS the levels are below max output.  The lower the level-the low you can run it or add boosting down low.  So it is a "sliding scale".

I would however make the argument that this is not the "intended usage" of the cabinet-and that you should use a highpass for the INTENDED usage of a cabinet.  I guess I did not make that clean

Sure.  In its intended usage, I run it with a HPF. 

Still, when it's EQed in order to flatten the sound, it's pretty much making it so the excursion will occur, on average, at about the same point given similar dB and at any frequency.  The PEQ settings are fairly similar to an inverted version of the excursion graph, but scaled differently to account for 6dB being double/half instead of the scaling in mm.  I was thinking the HPF with a Butterworth was halving the voltage at 35hz with its 3dB reduction at the corner frequency.  But I think it's 6dB that does that.  Linkwitz-Riley will give me 6dB, though.  But when I went back to the PEQ settings I used from REW for the sub (I put them into the Behringer DSP software that loads realtime into the nu3000), the 35hz notch is already doing that.  So I suspect with the convolving and even no HPF, I'm not at much risk of causing over excursion at 35hz or overheating at 60hz.  I don't convolve the deep bass, of course.  So that's probably also good.  Considering the excursion does not continue to increase the lower you go past 35hz, a HPF would seem to be more useful for utilizing power more efficiently from the amp than really protecting the driver.
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Ivan Beaver

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Re: Lab Sub handling
« Reply #25 on: November 23, 2013, 01:43:25 pm »

  I don't convolve the deep bass, of course.  So that's probably also good.  Considering the excursion does not continue to increase the lower you go past 35hz, a HPF would seem to be more useful for utilizing power more efficiently from the amp than really protecting the driver.
What do you mean "convolve" the deep bass?

A HPF does help protect the driver-not only from overexcursion-but also from rejecting freq that the driver can't reproduce-and therefore less heating going on.

Drivers fail from either overexcursion or heat or both.
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Ivan Beaver
Danley Sound Labs

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Benjamin Goulart

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Re: Lab Sub handling
« Reply #26 on: November 23, 2013, 07:08:32 pm »

What do you mean "convolve" the deep bass?

A HPF does help protect the driver-not only from overexcursion-but also from rejecting freq that the driver can't reproduce-and therefore less heating going on.

Drivers fail from either overexcursion or heat or both.

By convolving I meant EQing it flat using settings given by REW, which I don't do below 35hz anyway.  Interestingly, convolving the rest of the spectrum would be evening-out excursion if the excursion graph is to be trusted.

Right, I realize that over-excursion and heat now are both issues.  Would you say very low frequencies in general produce more heat?
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Ivan Beaver

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Re: Lab Sub handling
« Reply #27 on: November 23, 2013, 09:00:01 pm »

By convolving I meant EQing it flat using settings given by REW, which I don't do below 35hz anyway.  Interestingly, convolving the rest of the spectrum would be evening-out excursion if the excursion graph is to be trusted.

Right, I realize that over-excursion and heat now are both issues.  Would you say very low frequencies in general produce more heat?
Then why not say you just eqed instead of using a term that means something different.

I would not be concerned with trying to eq a system to even out excursion.  I have never heard of anybody doing or trying to do this.

The only time one freq produces more heat than another depends on the voltage level applied and the impedance at that freq.

By reducing the levels at frequencies that the sub cannot easily reproduce will reduce the heat.

Does it matter?  It depends on how hard the loudspeaker is being pushed overall and how much energy is present in the freq that would be cut by the HP filter.
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A complex question is easily answered by a simple-easy to understand WRONG answer!

Ivan Beaver
Danley Sound Labs

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Benjamin Goulart

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Re: Lab Sub handling
« Reply #28 on: November 24, 2013, 01:23:30 am »

Then why not say you just eqed instead of using a term that means something different.

I would not be concerned with trying to eq a system to even out excursion.  I have never heard of anybody doing or trying to do this.

The only time one freq produces more heat than another depends on the voltage level applied and the impedance at that freq.

By reducing the levels at frequencies that the sub cannot easily reproduce will reduce the heat.

Does it matter?  It depends on how hard the loudspeaker is being pushed overall and how much energy is present in the freq that would be cut by the HP filter.

It's just when I used the REW convolving settings in the nu3000's DSP Parametric EQ, and then compared that to the excursion graph, they seemed to be pretty similar if you considered one in mm of excursion and one in dB with 6bB being half or double the voltage, right?  It was actually unintentional but an interesting result.
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Ivan Beaver

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Re: Lab Sub handling
« Reply #29 on: November 24, 2013, 08:38:59 am »

It's just when I used the REW convolving settings in the nu3000's DSP Parametric EQ, and then compared that to the excursion graph, they seemed to be pretty similar if you considered one in mm of excursion and one in dB with 6bB being half or double the voltage, right?  It was actually unintentional but an interesting result.
Where did you place the mic to get the measurement?
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A complex question is easily answered by a simple-easy to understand WRONG answer!

Ivan Beaver
Danley Sound Labs

PHYSICS- NOT FADS!
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