Need a compressor, which?

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ronny31
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Joined: Fri Jul 29, 2016 3:14 pm

Need a compressor, which?

#1 Post by ronny31 » Wed Aug 03, 2016 2:32 am

I need two compressor settings for my subwoofer setup. And I need to know what compressor would fit the task. Cheap is ideal but I could go for something a bit up the price range assuming ofcourse it will then last forever.

The required setups are:
1. No gain to any of the frequencies just limiter so that they don't pop above their xmax limits on badly mixed bass music that people insist on playing at parties. So that I can lets say limit the gain such that it only hits the limiter slightly on most normal bass music and then refuses to go above that voltage irrespective of how high the source material is recorded. It should not add any gain if the signal is low.
2. Gain on all the bass frequencies (this compressor will be placed between crossover on sub out signal, and the amps), except those frequencies outside the subwoofer area. And also limited on the top like before. The goal being to hit the proper really loud voltages even if the source music has rather low bass.

The compressor would of course need to be able to switch between these settings with a few buttons. XLR in and out is a given. And I'd need some input on what sort of settings would get these results because I have messed around with a compressor software and it seems to think all music from different software has a completely different recording level. So I haven't got the faintest idea what would be a compressor setting that wouldn't just make the bass frequencies square on half the types of playback programs there are (youtube, spotify, windows media player, etc).

Grant Bunter
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Location: Ilfracombe Queensland Australia
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Re: Need a compressor, which?

#2 Post by Grant Bunter » Wed Aug 03, 2016 4:43 am

Hey Ronnie,
Welcome to the forum :)

Seriously, we need way more information!
What subs,what specs, what drivers, what's their voltage limit?

A compressor/limiter, while it can act as a limiter, isn't a brick wall limiter, which is what you need it seems.

Even tickling the limiter in terms of voltage can lead to burnt out voice coils, if you're pushing your driver beyond thermal limits, as distinct from RMS limits.

Number 1 depends on signal level. So if your "normal" music is nominally set to play at say 0db and the "badly mixed" stuff is bringing up +6dB compared to that, then what I said just above could/ might occur. In this case, there is no substitute for riding the faders on your mixer to keep the gain at 0dB.

Number 2, well, I'm not sure why you would want to do this.
Buy a unit that does crossover, limiting and gain all in one unit.
Then it's simply a matter of recalling 2 different settings...
Built:
DR 250: x 2 (melded array) with March 2012 plans.
T39's: 4 x 20" BP102 , 2 x 28" 3012lf.
WH8: x 3 with melded array.
Bunter's Audio and Lighting "like"s would be most appreciated...

Bruce Weldy
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Joined: Fri Nov 27, 2009 11:37 am
Location: New Braunfels, TX

Re: Need a compressor, which?

#3 Post by Bruce Weldy » Wed Aug 03, 2016 7:22 am

Grant Bunter wrote:Hey Ronnie,
Welcome to the forum :)

Seriously, we need way more information!
What subs,what specs, what drivers, what's their voltage limit?

A compressor/limiter, while it can act as a limiter, isn't a brick wall limiter, which is what you need it seems.

Even tickling the limiter in terms of voltage can lead to burnt out voice coils, if you're pushing your driver beyond thermal limits, as distinct from RMS limits.

Number 1 depends on signal level. So if your "normal" music is nominally set to play at say 0db and the "badly mixed" stuff is bringing up +6dB compared to that, then what I said just above could/ might occur. In this case, there is no substitute for riding the faders on your mixer to keep the gain at 0dB.

Number 2, well, I'm not sure why you would want to do this.
Buy a unit that does crossover, limiting and gain all in one unit.
Then it's simply a matter of recalling 2 different settings...
+1

Just get a dbx driverack.

6 - T39 4-25" 2-22" 3012LF
4 - OT12 2512 Melded/NSD2005
1 - T24
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

ronny31
Posts: 11
Joined: Fri Jul 29, 2016 3:14 pm

Re: Need a compressor, which?

#4 Post by ronny31 » Wed Aug 03, 2016 2:55 pm

Bridged Behringer EP4000 (same output as the old Europower 2500, so 1500w-ish continuous program power) on each Faital Pro 18XL1800 (1600w AES) in front loaded horns. So excursion limits are hit at about 108 volts with highpass 12db/oct at 30hz. They can do with less of a "brick wall" limit if I increase the highpass frequency a tad.

Is there a way to automatically adjust the overall volume with a dbx driverack unit?

The dbx driverack PA2 is cheap in Norway at the moment, remote control function is a bonus. Does the PA2 have volume control like the MiniDSP 10x10HD?

Grant Bunter
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Re: Need a compressor, which?

#5 Post by Grant Bunter » Wed Aug 03, 2016 4:40 pm

ronny31 wrote:Bridged Behringer EP4000 (same output as the old Europower 2500, so 1500w-ish continuous program power) on each Faital Pro 18XL1800 (1600w AES) in front loaded horns. So excursion limits are hit at about 108 volts with highpass 12db/oct at 30hz.

Did the designer of the FLH's loaded with your Faital Pro's, give you that limit?
FLH's place way more "pressure" on a driver.

It is normal convention here to have a minimum of a 24dB/octave slope on a HP, as maximum excursion occurs at the lowest frequencies. It's about protecting your drivers.


They can do with less of a "brick wall" limit if I increase the highpass frequency a tad.

No. If you think that, you don't know what a brick wall limiter is.
The brick wall limiter is always the last item in the signal chain, so that, regardless of what is done to increase the output in the signal chain, prior to the brick wall limiter, maximum voltage to the driver cannot be exceeded (except as earlier above, in my first response).
Sure, it helps in protection to raise HP, but it doesn't change the voltage limit.


Is there a way to automatically adjust the overall volume with a dbx driverack unit?
Not automatically, but yes, with your master faders on your mixer

The dbx driverack PA2 is cheap in Norway at the moment, remote control function is a bonus. Does the PA2 have volume control like the MiniDSP 10x10HD?

The PA2 is controllable via ethernet.
Built:
DR 250: x 2 (melded array) with March 2012 plans.
T39's: 4 x 20" BP102 , 2 x 28" 3012lf.
WH8: x 3 with melded array.
Bunter's Audio and Lighting "like"s would be most appreciated...

ronny31
Posts: 11
Joined: Fri Jul 29, 2016 3:14 pm

Re: Need a compressor, which?

#6 Post by ronny31 » Wed Aug 03, 2016 9:47 pm

Grant Bunter wrote:Did the designer of the FLH's loaded with your Faital Pro's, give you that limit?
FLH's place way more "pressure" on a driver.

I have arrived at that limit, I designed the enclosures.

It is normal convention here to have a minimum of a 24dB/octave slope on a HP, as maximum excursion occurs at the lowest frequencies. It's about protecting your drivers.

The closed rear volume is only 50 liters so this reduces much of the excursion that would otherwise be the case under the lowest loading frequency. 12db/oct filter is what the Ep4k has on 30hz.

No. If you think that, you don't know what a brick wall limiter is.

I assumed it was slang for a compressor setting or clip limiter that essentially cuts off the top of the sine wave if the peak of the sine wave is above a certain threshold.

Sure, it helps in protection to raise HP, but it doesn't change the voltage limit.

The voltage limit is only at the excursion peak (32hz and there about). Anywhere else and peaks of up to 140 volts is well within the handling of the driver as long as the overall power is not greater than 1600w AES according to this standard: http://diy-audio.narod.ru/litr/AES2-1984-r2003.pdf Of course, the Ep4k can't deliver over 110v for more than a short burst at a time.

The PA2 is controllable via ethernet.

Yes, but does it have a volume function somewhere in the software? Its not a remote if I need another remote to control the volume.

CoronaOperator
Posts: 1446
Joined: Wed Mar 25, 2009 7:07 pm
Location: Medicine Hat, Alberta, Canada

Re: Need a compressor, which?

#7 Post by CoronaOperator » Wed Aug 03, 2016 10:19 pm

A "brickwall" limiter is a compressor with a "zero" (or close to ie: 0.1ms) attack time and an infinite ratio. Once set, the voltage of the outgoing signal cannot exceed the setting you choose.

I'm not quite understanding why you want the 2nd compressor for a pa system only for certain songs. If the PA is balanced and you have enough rig for the gig then the bass knob on your channel strip EQ's (even DJ mixers have these) should help out with a song that is weak on bass. That will however raise the gain as you say "outside the subwoofer area" in the lower mids. The only thing that I can think of where outboard gear would really be necessary to add some low end to a song is very old recordings from ancient records where the recording device was not capable of recording the lower notes. In that case restoration in software or something like a subharmonic synthesizer could do the trick. That device doesn't boost the lower frequencies but actually adds in newer frequencies an octave below what is on the recording. If you really need something quick and dirty then have your driverack on the gain page for the subwoofer then all you have to do is turn the dial to up the gain, your limiter settings will stay intact. Be aware that just cranking the gain on the subwoofer channel does raise your sub/top x-over frequency and does put your system out of tune. If you need the bass raised only for the subs and only for a song here or there then it may be a worthwhile compromise.
Built:
17" width 10" driver Autotuba
2 x 29" width dual Lab12 Tuba60
6 x DR250 2510/asd1001
In progress:
2 x DR250 2510/asd1001
For best results, point the loud end of the array towards the audience

Grant Bunter
Posts: 5897
Joined: Mon Nov 28, 2011 11:12 am
Location: Ilfracombe Queensland Australia
Contact:

Re: Need a compressor, which?

#8 Post by Grant Bunter » Thu Aug 04, 2016 12:53 am

ronny31 wrote:
Grant Bunter wrote:Did the designer of the FLH's loaded with your Faital Pro's, give you that limit?
FLH's place way more "pressure" on a driver.

I have arrived at that limit, I designed the enclosures.

It is normal convention here to have a minimum of a 24dB/octave slope on a HP, as maximum excursion occurs at the lowest frequencies. It's about protecting your drivers.

The closed rear volume is only 50 liters so this reduces much of the excursion that would otherwise be the case under the lowest loading frequency. 12db/oct filter is what the Ep4k has on 30hz.

No. If you think that, you don't know what a brick wall limiter is.

I assumed it was slang for a compressor setting or clip limiter that essentially cuts off the top of the sine wave if the peak of the sine wave is above a certain threshold.

Sure, it helps in protection to raise HP, but it doesn't change the voltage limit.

The voltage limit is only at the excursion peak (32hz and there about). Anywhere else and peaks of up to 140 volts is well within the handling of the driver as long as the overall power is not greater than 1600w AES according to this standard: http://diy-audio.narod.ru/litr/AES2-1984-r2003.pdf Of course, the Ep4k can't deliver over 110v for more than a short burst at a time.

The PA2 is controllable via ethernet.

Yes, but does it have a volume function somewhere in the software? Its not a remote if I need another remote to control the volume.
Cool, your own design!
Love to hear how you arrived at your design and how you arrived at your voltage limit?

The PA2 will allow you to employ a 24dB/octave filter, that's safer (disable your EP4000 limiters).
It won't have a volume button as such. As CO said though, you can alter gain remotely.

I urge you to examine amplifier output and transient peaks. While the EP4000 may only put out 110V, and not sustain that for very long, transients in milliseconds in duration can be much much higher...
Built:
DR 250: x 2 (melded array) with March 2012 plans.
T39's: 4 x 20" BP102 , 2 x 28" 3012lf.
WH8: x 3 with melded array.
Bunter's Audio and Lighting "like"s would be most appreciated...

ronny31
Posts: 11
Joined: Fri Jul 29, 2016 3:14 pm

Re: Need a compressor, which?

#9 Post by ronny31 » Thu Aug 04, 2016 2:20 pm

Grant Bunter wrote:Cool, your own design!
Love to hear how you arrived at your design and how you arrived at your voltage limit?

The PA2 will allow you to employ a 24dB/octave filter, that's safer (disable your EP4000 limiters).
It won't have a volume button as such. As CO said though, you can alter gain remotely.

I urge you to examine amplifier output and transient peaks. While the EP4000 may only put out 110V, and not sustain that for very long, transients in milliseconds in duration can be much much higher...
If the voltage peaks happen quicker than about 6.25ms for a quarter wave, its higher up in frequency than 35hz and excursion isn't a problem.

Image
Image
http://i.imgur.com/U7BF1gf.jpg
(last one is too large just open in new tab)

Its designed to stand upright behind the seating with the horn mouth at the ceiling, leaving about 35cm (just over a foot) to the ceiling. The resulting open area in 2 sides is enough to match the horn mouth area so it can be placed in a corner as long as both aren't placed in the same corner. The footprint per enclosure is just 67x64cm (just over 2x2 feet) but the output is as you can see, in 0.5 x Pi radiation (so slightly louder in a real world room unless the wall behind the seating is very wide). Any paint scheme can be applied to the outside for blending it in instead of having blaring black boxes. Helped by the fact that the drivers aren't visible.
CoronaOperator wrote:A "brickwall" limiter is a compressor with a "zero" (or close to ie: 0.1ms) attack time and an infinite ratio. Once set, the voltage of the outgoing signal cannot exceed the setting you choose.

I'm not quite understanding why you want the 2nd compressor for a pa system only for certain songs. If the PA is balanced and you have enough rig for the gig then the bass knob on your channel strip EQ's (even DJ mixers have these) should help out with a song that is weak on bass. That will however raise the gain as you say "outside the subwoofer area" in the lower mids. The only thing that I can think of where outboard gear would really be necessary to add some low end to a song is very old recordings from ancient records where the recording device was not capable of recording the lower notes. In that case restoration in software or something like a subharmonic synthesizer could do the trick. That device doesn't boost the lower frequencies but actually adds in newer frequencies an octave below what is on the recording. If you really need something quick and dirty then have your driverack on the gain page for the subwoofer then all you have to do is turn the dial to up the gain, your limiter settings will stay intact. Be aware that just cranking the gain on the subwoofer channel does raise your sub/top x-over frequency and does put your system out of tune. If you need the bass raised only for the subs and only for a song here or there then it may be a worthwhile compromise.
The second compressor setup is for when the db meter is taken out of its box.

Grant Bunter
Posts: 5897
Joined: Mon Nov 28, 2011 11:12 am
Location: Ilfracombe Queensland Australia
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Re: Need a compressor, which?

#10 Post by Grant Bunter » Thu Aug 04, 2016 4:35 pm

Thanks!

So it's always used in the house?
HT and music?
Do you run it as a 2.1?

Would you miss a couple/few Hz at the bottom end?
Probably not, since 30Hz is -10dB compared to 38-40Hz.

The miniDSP 10 x 10 looks to be expensive.
It would be a shame to get it based solely on the remote having volume control capability :shock:

It would be worth trying to get a PA2. You're no worse off if you find it doesn't do exactly what you want in the end, being an in demand pro audio product, there's a good "slightly/lightly used" market for them...
Built:
DR 250: x 2 (melded array) with March 2012 plans.
T39's: 4 x 20" BP102 , 2 x 28" 3012lf.
WH8: x 3 with melded array.
Bunter's Audio and Lighting "like"s would be most appreciated...

ronny31
Posts: 11
Joined: Fri Jul 29, 2016 3:14 pm

Re: Need a compressor, which?

#11 Post by ronny31 » Thu Aug 04, 2016 10:07 pm

Grant Bunter wrote:Thanks!

So it's always used in the house?
HT and music?
Do you run it as a 2.1?

Would you miss a couple/few Hz at the bottom end?
Probably not, since 30Hz is -10dB compared to 38-40Hz.

The miniDSP 10 x 10 looks to be expensive.
It would be a shame to get it based solely on the remote having volume control capability :shock:

It would be worth trying to get a PA2. You're no worse off if you find it doesn't do exactly what you want in the end, being an in demand pro audio product, there's a good "slightly/lightly used" market for them...
It will be used for everything. Gaming, movies, music, and all types of music.

It is a 2.1 setup, yes.

The gain from having two in close proximity will to some extent give a little extra db below 40hz (anyone happen to have the links to relevant papers on FLH placement gain?).
In any case making an enclosure that loads lower is obscenely impractical if it is to be efficient.
Floorspace is going for about 13 grand per square meter (1200 dollars per square foot) locally so its cheaper to add wooferage than use floorspace. This enclosure is more space and volume efficient than the equivalent amount of vented enclosures.

There's a 90 day return policy where I'd buy the PA2 (30 day by law no questions asked), so trying one costs only the shipping here and back. But I like to know precisely the limitations of everything I buy, since I get paid by the bank to have money in it and thus can be slow to decide and make money on it.

CoronaOperator
Posts: 1446
Joined: Wed Mar 25, 2009 7:07 pm
Location: Medicine Hat, Alberta, Canada

Re: Need a compressor, which?

#12 Post by CoronaOperator » Thu Aug 04, 2016 10:18 pm

ronny31 wrote: The gain from having two in close proximity will to some extent give a little extra db below 40hz (anyone happen to have the links to relevant papers on FLH placement gain?).
In any case making an enclosure that loads lower is obscenely impractical if it is to be efficient.
Floorspace is going for about 13 grand per square meter (1200 dollars per square foot) locally so its cheaper to add wooferage than use floorspace.
http://www.billfitzmaurice.com/THT.html

Add in the cabin gain of an average room (12dB per octave below 30 Hz) and you can end up with response to 10Hz with 110dB sensitivity.

giving the highest output possible from a 15x18 inch footprint.
Built:
17" width 10" driver Autotuba
2 x 29" width dual Lab12 Tuba60
6 x DR250 2510/asd1001
In progress:
2 x DR250 2510/asd1001
For best results, point the loud end of the array towards the audience

ronny31
Posts: 11
Joined: Fri Jul 29, 2016 3:14 pm

Re: Need a compressor, which?

#13 Post by ronny31 » Thu Aug 04, 2016 10:59 pm

I'd like to find the papers themselves if anyone happens to have the links at hand. This is hardly an average anything :mrgreen: Not least because the poor bast... I mean listeners, will be in a sofa touching the base of the two FLHs.

CoronaOperator
Posts: 1446
Joined: Wed Mar 25, 2009 7:07 pm
Location: Medicine Hat, Alberta, Canada

Re: Need a compressor, which?

#14 Post by CoronaOperator » Thu Aug 04, 2016 11:02 pm

ronny31 wrote:
I'd like to find the papers themselves if anyone happens to have the links at hand.
http://www.billfitzmaurice.com/Ordering.html
Built:
17" width 10" driver Autotuba
2 x 29" width dual Lab12 Tuba60
6 x DR250 2510/asd1001
In progress:
2 x DR250 2510/asd1001
For best results, point the loud end of the array towards the audience

ronny31
Posts: 11
Joined: Fri Jul 29, 2016 3:14 pm

Re: Need a compressor, which?

#15 Post by ronny31 » Thu Aug 04, 2016 11:38 pm

CoronaOperator wrote:
ronny31 wrote:
I'd like to find the papers themselves if anyone happens to have the links at hand.
http://www.billfitzmaurice.com/Ordering.html
I'm referring to peer review papers about front loaded horn theory. Sorry for the confusion.

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