Setting limiters on Berry LMS
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URL: https://forum.speakerplans.com/forum_posts.asp?TID=27651
Printed Date: 27 March 2026 at 7:37am
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Topic: Setting limiters on Berry LMS
Posted By: drivebycar
Subject: Setting limiters on Berry LMS
Date Posted: 10 June 2009 at 1:45pm
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Hey, I wanted to set up limits on our bins, and was wondering if anyone could give a bit of an explanation on how it works. I have a berry LMS. Had a play around with it but not entirely sure how to go about it Thanks  |
Replies:
Posted By: AlfieDring
Date Posted: 10 June 2009 at 2:00pm
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Ok no problem. Gather the following info..... watts RMS powerhandling of bin(s) max watts RMS output of amplifier(s) Input sensitivity of amplifier(s) (in volts :P) And ill see if we can't conjour up some settings :) BTW i take it you mean the behringer DCX2496? Alf |
Posted By: drivebycar
Date Posted: 10 June 2009 at 2:08pm
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Hi mate, Bins are loaded with pd186's so RMS is 700W Amp powering them is a Proline 2700 currently running one a side at 8ohm so 900W Dont know what the input sensitivity is though im afraid? And am at work so cant find out till later. Yep its a DCX2496 Cheers |
Posted By: james folkes
Date Posted: 10 June 2009 at 2:21pm
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i live in fear of dcx limiters... the only time i have ever blown speakers in my whole time doing this was when i decided to trust the ultradrive limiters to keep my amps out of clip. never again. norty has had some 18lx60s go pop under similar circumstrances too. i must temper this statement with information received that <20Hz run their hogs with the limititer lighting up all night long and have never had a problem.
i don't trust them though...
james. ------------- mardy hippy. |
Posted By: AlfieDring
Date Posted: 10 June 2009 at 3:15pm
Hmmm ok, i cant find the 2700 input sensitivity either... bit annoying. All the other t.amps seem to be 0.775v so ill do a worked example with that and if the 2700 is different just do it again with 1 or 1.4 or whatever it is. Have a read of this thread from a while ago...... http://www.speakerplans.com/Forum/output-levels-input-sensitivity-dbu-dbfs-ummmm_topic23486.html?KW=%2B22dBu - http://www.speakerplans.com/Forum/output-levels-input-sensitivity-dbu-dbfs-ummmm_topic23486.html?KW=%2B22dBu ... it will explain in a bit more detail the following maths. 0.775v = 0 dBu The ultradrive says +22dBu = 0dBfs so in order to output 0 dBu we set the limiter to -22dBfs. With the limiter set at -22dB the output from the ultradrive will be constrained to 0.775v and the output from the amp to 900w. To further drop this to 700w we work out the dB power ratio of 900/700 and subtract this from the previous -22dB... 10 Log (900/700) = 1.091dB -22 - 1.091 = -23.091dB Setting the limiter to -23.091dBfs should keep the output power down to 700w IF the proline has 0.775v input sensitivity. For different sensitivities see below. 0.775v = 0 dBu (as before ) 1v = 2.22dBu 1.4v = 5.14dBu So if for example its 1v not 0.775v just add 2.22dB to the previous answer giving -20.871dBfs. Hope that makes some sense. If not then check that thread i posted ^ chickenfizz shows another method for working this out that is i think equivilant? not totally sure though. LASTLY (at last!) I reckon you can probably safely put 900w into your bins anyway, would be very unlikely to cause a problem so you could just set the limiters to stop the amp clipping (-22dB) and not bother shaving off that last decibel  EDIT: utterly forgot about release time. This parameter changes how long the limiter takes to open up again (under the control of an envelope, it dosent just ping open suddenly once the times up!) I reccomend for proper "limiter" behaviour setting it for the longest time possible or at least 5 seconds. |
drivebycar wrote:Posted By: drivebycar
Date Posted: 10 June 2009 at 4:39pm
Wow, thanks for that mate! Ill have a read of the other thread later on as well.  |
Posted By: Timebomb
Date Posted: 11 June 2009 at 12:42am
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Yeah Proline 2700 is 0.775V unloaded which is -23.5dB on the dcx, the
clip point drops a bit when you put some speakers on it and drive them
them with a signal though, due to the voltage drop, we have had to put
the limiter down to -24dB on the dcx (as far as it will go) and take
the input attenuator on the amp down a little to stop it
clipping. Calcluated settings are never spot on, it depends on
how much vairation in voltage gain your getting through the amp, wich
vairies under different conditions. ------------- James Secker facebook.com/soundgearuk James@soundgear.co.uk www.soundgear.co.uk |
Posted By: Saul
Date Posted: 11 June 2009 at 9:58am
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i think there's also a way to set them for maximum gain structure. you disconnect your cabs from the amps and then run pink noise through the system. Turn up the mixer until it just starts clipping and then reduce a little. Then run this into the LMS with the limiters off. and into your amp. turn up the amp until it just starts clipping, then reduce it a little. Remember the position of the amp attenuators and then turn them up full again. Then turn on the limiters and reduce until your amplifiers stop clipping. Once you've done all the bands, reduce the amps back to the "remembered" position, and reduce the mixer too. If your amps are too powerful for your drivers, this won't protect them, but it's easier than doing all the maths. I think i saw this in a DBX manual. I've personally always used the maths method, but i have tried the gain structure method, and it seems to work ok. |
Posted By: AlfieDring
Date Posted: 11 June 2009 at 10:47am
@ Drivebycar, listen to this ^^^! Real world conditions always take priority over the calculations of an unknown stranger @ Timebomb, what your saying is good advice overall but where's this -23.5dBfs on DCX figure come from? Have you measured it to be different from whats indicated in the manual? The specs indicate -22dBfs for 0.775vrms not -23.5 |
Posted By: jonminns
Date Posted: 11 June 2009 at 2:24pm
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I genuinely think ultradrive limiters are brilliant Fairly unaudible, and they work I've overpowered v18s in tough boxes with the limiters taking 12dB off constantly all night to see what happens... nothing DBX DRPA limiters are sh*te however |
Posted By: Tony Wilkes
Date Posted: 11 June 2009 at 2:40pm
+1 used correctly they can be very useful Tony |
Posted By: james folkes
Date Posted: 11 June 2009 at 3:08pm
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...which really makes me wonder, what on earth could we have been doing wrong that night? general opinion has it that they work, next time i have one out i shall have a furtle.
james. ------------- mardy hippy. |
Posted By: Timebomb
Date Posted: 11 June 2009 at 4:36pm
Edit, The -23.5dB limiter setting for the Proline came from sheet of limiter settngs i made up for different amps a while ago. I was just taking it down another 1.5 dB to compensate for loading. EG the behringer amps state +4dBU, so thats -18dB on the limiters, but thats loaded at 8 ohms (i think its 8 ohms, not sure). Unloaded the behringers clip with the limiter at about -16.5dB. The proline input states 0.775V, which is 0dBU, so the limiters can be set to -22dB, but thats unloaded, so i took another 1.5dB off for the seting sheet i made. Yeah for 0.775V input you could start with the limiter at -22dB, but keep an eye on the amp and be prepaird to take it down a bit. Also worth noteing that the behringers input sensitivity is 3dB lower when in bridge mode, im not sure on the QSC equivilent though, i know the qsc 4050HD is the same in bridge/stereo mode. ------------- James Secker facebook.com/soundgearuk James@soundgear.co.uk www.soundgear.co.uk |
Posted By: dlyxover
Date Posted: 11 June 2009 at 4:46pm
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i normally need to run my dcx limiters at around -18 to stop clipping. On my sub15 (PD154) and wedges (BMS 12N620) being run of 1 channel of a qsc rmx2450 each. Is it because there underpowered? ------------- Lignum_ww@icloud.com GNKaudio@icloud.com |
Posted By: Timebomb
Date Posted: 11 June 2009 at 4:49pm
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If the RMX is the same as the behringer EP2500 wich mostly it is, then yeah -18dB is about right. ------------- James Secker facebook.com/soundgearuk James@soundgear.co.uk www.soundgear.co.uk |
Posted By: drivebycar
Date Posted: 11 June 2009 at 4:50pm
| So have the amps right open, and limiter set up as above, then bring the amp down if necessary? |
Posted By: Timebomb
Date Posted: 11 June 2009 at 5:04pm
Yeah, or bring the limiter down a bit more if needed and leave the amps fully up. Though the DCX limiter only gos to -24dB so you might have to take the amps down a little. ------------- James Secker facebook.com/soundgearuk James@soundgear.co.uk www.soundgear.co.uk |
Posted By: drivebycar
Date Posted: 11 June 2009 at 5:07pm
Righto, definately worth a mess about as we might be hiring out soon. Thanks everyone 
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Posted By: doober
Date Posted: 11 June 2009 at 9:09pm
Can you clarify this? are you saying it's 3dB less sensitive, ie requires +7dBU for full output, or the other way, +1dBU? I might have to do a bit of Berri bridging soon. Thanks Kieran ------------- Blahblahblah |
Posted By: Timebomb
Date Posted: 12 June 2009 at 1:09am
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+1dBU as i remember, so -21 on the DCX, id check it first without the
speakers connected though, should clip at about -19.5dB ish.
------------- James Secker facebook.com/soundgearuk James@soundgear.co.uk www.soundgear.co.uk |
Posted By: doober
Date Posted: 12 June 2009 at 4:54pm
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Thanks, very useful info, I'll give that a go.
I've sometimes used a less scientific approach and set the limiters as low as they go, -24dB, put a loud signal into the dcx, turned the amps up full, then raise the limiter until the amp just clips, then lower it a notch. A bit risky if you want to limit power to the driver, but works ok if you just want to avoid clipping. Not very easy when the amps are at the end of a 50m multicore though. ------------- Blahblahblah |
Posted By: gwarntek
Date Posted: 12 June 2009 at 5:15pm
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How come amps have switchable sensitivity then? Just incase you get a very weak input??
By choosing +1.44v over 1v or 0.775v, will it make the amp louder per dBu that is input?
Or if you use a higher sensitivity, you use a lower limiter threshold?
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Posted By: jethrocker
Date Posted: 12 June 2009 at 9:47pm
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Exactly that, sometimes you have a weak signal, sometimes a strong one. Changing input sensitivity just changes the working level or gain range of the input stage. Nothing will make your amp "louder", for a given set of connected speakers there will be a max spl based on the speakers sensitivity, power handling and power supplied. The max amp power doesn't change, the sensitivity figure just tells you how large an input signal will produce full output. If you use a higher sensitivity (ie 0.775V) Then yes, you will need the limiter to start working at a lower level, as the amp will reach its limits with a smaller input signal. |
Posted By: studio45
Date Posted: 12 June 2009 at 10:10pm
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i trust the dcx limiters implicitly on my rig, all the time, and haven't blown anything yet in 20 gigs. Set them only to keep the amps from showing me a red light ever. However I'm of the opinion that when trying to use em with an 0.775v amp, a 10dB attenuator between the dcx and the amp would be useful to get the limiter setting somewhere up nearer -14dbu than -24dbu. Lets the output D/A use more Bits! 20Hz can set his bass limiter at -24 and still make his Inf8's inbuilt limiters activate, so it's basically not doing much for him there. However the advice he recieved from Void was that his Inf8 + 4x V18-1200 combo requires NO extra limiting - the amp just sorts itself out via that nifty VPL circuit! Wish i knew exactly how that worked. Have to wait 50 years till the Freedom of Information Act kicks in eh :) He's not blown anything yet though at a dance a few weeks back he managed, by the smell of it, to burn a layer of varnish off the coils. Had us all running up to him in panic "yer bins are cooking mate!!" but they lived to wobble many more days ------------- Studio45 - Repairs & Building Commotion Soundsystem -Mobile PA |
Posted By: jonminns
Date Posted: 13 June 2009 at 5:13pm
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The attenuator on the outputs is an excellent idea, its one i have put into practice and works spot on Means you can drive the dsp harder, have more control, more sampling, and more lights :P Jon |
Posted By: drivebycar
Date Posted: 17 June 2009 at 12:30pm
| Set them all up yesterday, so looking forward to testing it out at the weekend. Just one more question, on the attack & release, what is an average value for these? |
Posted By: Saul
Date Posted: 17 June 2009 at 12:41pm
| does anyone know the input sensitivities for UKP1300 and UKP2100 |
Posted By: cuivenion
Date Posted: 22 June 2009 at 6:19am
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So, just to confirm I'm doing this correctly, If i want to use the limiters on the dcx correctly I should set for the fastest attack, longest release and the highest ratio to protect the speakers? Here's my system: QSC PLX3402 running 1 HZ500 (500 wrms) per channel JBL MPX1200 running 1 Dare E18DR (Fane 18XB 4ohm) per channel The PLX input sensitivity is 1.7 volts at 4ohms so I've increased the output on the dcx on these channels by 6.9db and set the limiters to -16.6db. I've estimated the MPX's sensitivity at 4ohms to 0.775 volts, so I have left the the output on the dcx on these channels at 0DB and set the limiter to -23db. The system sounds fine when playing music as i don't push it anywhere near the limit. I use it for live sound too though, and thats a different story. I just want to check I'm protecting the speakers properly, and in the right way. ------------- help!!!!!!!!!! |
Posted By: levyte357
Date Posted: 22 June 2009 at 11:08am
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Unfortunately, the Proline 2700 is a bit rubbish @ 8 ohm stereo, and when I had mine, I only ever used it in 4ohm stereo or 4ohm bridge, due to the lack of power in 8ohm stereo. So allowing a max signal of 0db to arrive at the Proline, in 8 ohm stereo will result in dissappointment. However someone on here has said, the protection on 2700 is not very good, and clip light on amp may mean driver life just shortened. When using the DCX limiting on kick/mid tops, I typically set limiters to -19. I usually have powerful amps in this range, so setting those to 0db sensitivity and 75% gain travel always works with this, and nothing blown. I dont use DCX limiters on sub. I use external MDX4600 XL.
[hijack] Cuivenon, please compare the MPX and PLX in 4ohm bridge on sub sometime, and let me know results. You maybe pleasantly suprised. [/hijack] ------------- "Who am I? I'm the guy who does his job.. You must be the other guy". |
Posted By: cuivenion
Date Posted: 22 June 2009 at 12:54pm
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[/QUOTE] [hijack] Cuivenon, please compare the MPX and PLX in 4ohm bridge on sub sometime, and let me know results. You maybe pleasantly suprised. [/hijack] [/QUOTE] Won't be doing that anytime soon mate, not when I'm running 4ohm speakers! What's meant by [/hijack]? ------------- help!!!!!!!!!! |
Posted By: super-hero
Date Posted: 23 June 2009 at 12:32am
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Great thred this, as many people would like to know how to set their limiters properly, myself included.
So here is my scenario.
My amp sensitivity is 1.07v rms @4r and delivers 1100watts.
If I want to run a speaker that is only rated at 150watts @4r
should I set the limiters 8.65dB lower, or, reduce the input gain on the dcx by 8.65dB. and if I reduce the input gain, how does that affect my limiter settings?
Or should I reduce my input gain by 8.65dB and lower my limiters by 8.65dB. ------------- I'm not an animal, I'm a human being. |
Posted By: doober
Date Posted: 23 June 2009 at 3:26pm
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The limiter stops the output exceeding a given level. The input gain affects how much input is required to hit the limiter, but not the level you're limiting to.
I would set the limiter 8.65dB lower (assuming this is the correct attenuation to limit the amp to 150w, I've not checked your maths), and then lower the output gain on that channel until the balance between bands sounds right. The input gain level is a matter of personal preference, you can set this high and the outputs low or vice versa. I try to keep both as near 0dB as possible, although the output gains will usually vary with each frequency band due to different power levels and efficiency of drivers. The hf will almost certainly be a lot lower than the rest. Hope that makes sense Kieran ------------- Blahblahblah |
Posted By: phildat
Date Posted: 14 June 2010 at 7:43pm
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bumped this for later reference. ------------- Its just a ride. |
Posted By: phildat
Date Posted: 23 June 2010 at 8:34am
anybody know where the link to this maths stuff is?? ------------- Its just a ride. |
Posted By: jack-red-eye
Date Posted: 17 January 2011 at 5:45pm
its not on the cerwin vega website and i cant find anything for the ukp on the tiniterweb??
Is there a way to calculate it?
|
Posted By: Adam_Iron_Horse
Date Posted: 21 April 2011 at 11:30pm
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Hey really useful thread but I've not really got my ultradrive set up right. I just slapped on -22db limiters on all the channels as I was in a rush when I first got it and set it up for the first gig. My amps are Peavey cs1200x - 1800W bridged into 4ohms driving 2 Pd. 186 (700W RMS each)sensitivity 1.4V C-audio SR707 - 825W a side into 4ohm driving 2 eminence deltas a side (400W RMS each) but couldn't find the sensitivity of the amp. Soundlab G097M (I know) - 400W a side into 8ohm driving one unbranded 2" compression drivers a side (120W RMS each) input sensitivity of 1V can anyone help me? well i know someone on here could but could someone help me? :) |
Posted By: kedwardsleisure
Date Posted: 26 April 2011 at 11:55pm
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I did a little video here of an ultradrive limiter in action http://www.youtube.com/v/HrsEiIt7jQ8 - http://www.youtube.com/v/HrsEiIt7jQ8 ------------- Kevin North Staffordshire |
Posted By: cravings
Date Posted: 27 April 2011 at 12:00am
| wow. very clean. |
Posted By: SamV
Date Posted: 27 April 2011 at 4:45am
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I have a question. I think I might have a weird ultradrive. I go 0db out of my desk (Soundcraft), the input on the DCX is at 0db, the outputs set to 0db for bass, -4db for mids and -7db for tops. This is feeding Matrix XT6004, CH1/2 doing 2r bass, CH3/4 doing 4r mids and UKP2400 doing 4r tops. and I'm only just hitting 0db/+3db on the amps. Seem to have had no issues for years. Should I not be getting like +22db on the amps? |
Posted By: dymondaudio
Date Posted: 27 April 2011 at 8:56am
What is the input sensitivity of the Matrix XT series? We use those amps with an XTA processor and it would be nice to know that the limiters are set correctly (or at least the maths behind the settings is correct).
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Posted By: SamV
Date Posted: 27 April 2011 at 3:43pm
| You know I don't actually know lol. I use gain structure rather than limiting. |
Posted By: Spesh
Date Posted: 27 April 2011 at 6:15pm
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This is a good thread. I need to properly set the limiters on my DCX. Having CA18's powering my Labs worries me and I always have to keep an eye on things. Even if I keep the amps out of clip, I'm still not sure whether or not the drivers are getting too much juice.
------------- Symmetry Soundsystem |
Posted By: colinmono
Date Posted: 27 April 2011 at 6:47pm
No. Remember, dB (note the lack of suffix) is a relative scale (measures the differences between two levels) and tells you nothing about the absolute level of the signal you are measuring. When you say 0dB, you need to know - 0dB compared to what? Your amps are likely to be calibrated so that on the meter, 0 dB = +4 dBu. dBu means voltage compared to 0.775 volts, i.e. 0dBu = 0.775 volts. +4dBu is commonly used as the 0dB meter level on analogue pro audio kit. If you put +4dBu into the Ultradrive (i.e. what you are likely to be putting out from you mixer), you will get 4dBu out the other end (provided all gain settings are at 0). I think the confusion arises because of the way the Ultradrive's meters are labeled. Full scale on the Ultradrive = +22dBu, so a 0dBu signal will read as -22dB on the Ultradrive meter. This is standard for digital kit, but confusing if you're only used to analogue gear / metering. |
Posted By: SamV
Date Posted: 27 April 2011 at 11:36pm
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By that I meant that the mixer is outputting 0db (+4dbu). The input on the DCX is 0db on it's own meters not -22db which people say is true 0dbu on the DCX? If I wanted 0dbu (+4db) across the board what settings should the DCX be on? |
Posted By: colinmono
Date Posted: 28 April 2011 at 8:17am
Really? Does your DCX meter look like this: 
If you are putting +4dBu in to the DCX you will get +4dBu out if: - the input gain controls on the DCX are all set to 0dB - the output gain controls on the DCX are all set to 0dB Obviously there are a number of other settings that can affect the output - limiter, e.q., crossover etc. |
Posted By: SamV
Date Posted: 28 April 2011 at 8:57am
| This is the thing, I thought 0dbu in would be -22 on those meters? The meter deffo isn't aswell lit up |
Posted By: colinmono
Date Posted: 28 April 2011 at 9:30am
If you put 0dBu in, you normally see something like this:  i.e. about -22dB, sometimes referred to as -22dBFS, as we mean -22dB relative to full scale or "FS" |
Posted By: colinmono
Date Posted: 28 April 2011 at 9:39am
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I've just realised where you may be getting confused. The meters on the DCX are labeled in dBFS, i.e. dB relative to "Full Scale" (+22dBu). The input and output gain settings are labeled in dB relative to the input level. They add or subtract to whatever you put in. In other words, if you set the input gain & output gain to 0dB (not -22dB): +10dBu in = +10dBu out +4dBu in = +4dBu out Note: you will see more lights lit up for the +10dBu input. Am I helping or just making things worse?  |
Posted By: SamV
Date Posted: 28 April 2011 at 12:14pm
| Ah gotcha that makes sense :) sorry for being a bit dim |
Posted By: mucsavage
Date Posted: 02 May 2011 at 3:37pm
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This is a really great thread. One question I am trying to confirm. Is the 0dB mark on the master output of a DJM-600 +4dbu? I am trying to confirm and searching for specs in Goggle but can't find it |
Posted By: SamV
Date Posted: 02 May 2011 at 3:45pm
| Usually is yes. |
Posted By: mucsavage
Date Posted: 02 May 2011 at 3:46pm
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Ah just found this, ---------- Output Specs & Terminals Master Out 1 1 x (XLR) +2 dBu / 600 Ohm 1 x (RCA) +2 dBu / 10k Booth 1 x (RCA) 0dBv / 600 Ohm Record 1 x (RCA) -8dBu / 10k Send 2 x mono (Phone Jack 6.3mm) Headphone Monitor Out 1 x (Jack 6.3mm) -------------- http://www.gereg.co.za/CodeMaster/DJ/DJM600.html Would this be the values for 0dB on the master output? |
Posted By: colinmono
Date Posted: 03 May 2011 at 10:32am
Yes, I think they will be the output for a 0dB meter reading. The specs in the manual give the master out (XLR) as 1.23V (i.e. +4dBu) though, not the +2dBu you quoted. http://www.pioneer.eu/uk/products/archive/DJM-600/media.html - http://www.pioneer.eu/uk/products/archive/DJM-600/media.html |
Posted By: phildat
Date Posted: 12 May 2011 at 9:33pm
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I use an aphex exciter in my set.if I tweak it is this altering the gain structure in a big way? ------------- Its just a ride. |
Posted By: phildat
Date Posted: 12 May 2011 at 9:35pm
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It's the 204 model... ------------- Its just a ride. |
Posted By: hollywd901
Date Posted: 24 August 2011 at 4:02am
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still searching for my answer...here are my specs of my system, can someone please help with the limiter...thanks! 2 cabs loaded each with 1 eminence 3012lf speaker says 8ohms and 450 watts rms my amp is a behringer ep2500 says 500 watts rms @ 8 ohms (in stereo mode) input sensitivity of amp says: vRms (@8w) 1.23v (+4.0dbu) anyone's help is appreciated, the more i learn or think i learn, the dumber i feel... |
Posted By: toastyghost
Date Posted: 24 August 2011 at 4:20am
For sustained musical content with minimal crest factor you need to set your limiters a couple of dB lower than you calculate to relieve thermal stress on the drivers. If you're using an LMS that works in dBu rather than dBFS (seemingly all of them other than the Behringer) then use this: http://www.mediafire.com/?n7f4f4110tpf2mu" rel="nofollow - http://www.mediafire.com/?n7f4f4110tpf2mu It's been linked before but seems a fair few people have missed it. It helps you figure out the best attack time for the output's passband too, which is important because if you set your attack or release too fast you can end up with horrible bass distortion - an XTA unit does these calculations on the unit for you, if you want it to, and seems to do a pretty good job of it as well. I'm going to shamelessly copy this section from page 51 of the DP548 manual, which you can get from the XTA site here http://www.audiocore.co.uk/pdfs/DP548_manual.pdf" rel="nofollow - http://www.audiocore.co.uk/pdfs/DP548_manual.pdf . It's this kind of thing that separates the top tier of crossover units from good but cheap ones like the DCX in my opinion:
Unfortunately the DCX doesn't let you adjust limiter attack times, nor does it have automatic envelope adjustment as far as I'm aware. I currently use DBX LMS units, which do tick all those boxes but not on par with the quality of limiting you get from a correctly set XTA. Perhaps this is why people have damaged drivers despite thinking they have their limiters set correctly? |
Posted By: hollywd901
Date Posted: 25 August 2011 at 3:24pm
| can anyone help me with my limiter question 2 posts above,,,weekend is coming soon, thanks! |
Posted By: mucsavage
Date Posted: 25 August 2011 at 10:25pm
I think is it, open to corrections though: ------------ 0 dBu in Ultradrive = -22dB to get 1.23v out of the Ultradrive set limiter to -22dB + 4 = -18dBfs = 500W You want this to be 450W 10 Log (500/450) = 0.4575dB -18dBfs - 0.4575 = -19.54 dBfs ------------- |
Posted By: Timebomb
Date Posted: 25 August 2011 at 11:46pm
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Just start with all bands set at -24dB, 4000ms release, amp gains fully open, if a particular band runs out of headroom and hits the limiter then turn the limiter threshold up and watch the corresponding amp for clipping, if it clips then take the limiter back down until it stops clipping, calculations arnt going to be that accurate, voltage gain varies too much with most amps so your best just watching the clip indicator and adjusting limiter threshold. ------------- James Secker facebook.com/soundgearuk James@soundgear.co.uk www.soundgear.co.uk |
Posted By: S DeXter
Date Posted: 26 August 2011 at 1:11pm
I think they are probably OK if the release time is set quite long. However I too have had similar problems with the DCX limiters :( ------------- Enjoy your self...... It's later than you think....... |
Posted By: festival people
Date Posted: 02 November 2011 at 3:46pm
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Hiya, I gave a good manual method because I too have blown drivers with a "mathamtical" aproach to limiters on the dcx.......I think sometimes the calibration may be a little off......but it is a good start point.......but as I said, I have a link to the dcx from my laptop and monitor the dcx at the sound desk so can adjust on the fly if the roadies indicate redl lights at the stage end.....lol
regards
dave
|
Posted By: SebP
Date Posted: 09 November 2011 at 5:47am
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There's a online calc for DCX2496 here: http://hornplans.free.fr/limiteur_dcx2496.html" rel="nofollow - http://hornplans.free.fr/limiteur_dcx2496.html |
Posted By: phildat
Date Posted: 09 November 2011 at 9:43am
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just tried that above thanks so let me get this right using an amp 1900 watts 4 ohms...the limiter needs to be set at 19.2 threshold? just double checking with others...? ------------- Its just a ride. |
Posted By: vibez
Date Posted: 09 November 2011 at 5:28pm
| My berry limiters were set by Tony Wilkes and they work perfectly, have been set for over 12 months now and my rig has been pushed hard many times without losing any drivers. Thanks again Tony |
Posted By: Tony Wilkes
Date Posted: 10 November 2011 at 7:38am
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It seems to me that pepes expect their limiters to be able to be set to within 0.1db of absolute max. power and still protect the rig. If they are set-up a little bit conservative and lets be honest if you constantly have to push your gear on or near to 100% all of the time you are doing things totally wrong then you should never blow a driver apart from amp failures or bad design. Just wind it back 1-1.5db that's all it takes. Tony ------------- www.forteaudio.eu - BMS - db-Mark Processors - Lexon (SAE) |
Posted By: toastyghost
Date Posted: 10 November 2011 at 3:24pm
Depends on the amp input sensitivity. |
Posted By: space141
Date Posted: 09 October 2015 at 9:51am
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Know this thread has been dormant for a few years but I have found it rather useful as I am just setting up my first soundsystem. I am having difficulty understanding how you calculate the ratio of power so that you are not running your amp at full tilt. The equation below is a little confusing:
What does the 10 Log stand for as 900/700 = 1.29 I understand we're trying to work out a ratio here but need a little assistance getting my head round this one. My amps are a QSC RMX850 & RMX1450 which both have an input sensitivity of 1.15v (+3.4dBu) which I am running in bridge mono mode into 8ohm speakers with an output power of 530W & 800W respectively. Cheers.
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Posted By: DMorison
Date Posted: 10 October 2015 at 3:03pm
Log means you take the base 10 Logarithm of the ratio in the brackets (easily available on any scientific calculator or spreadsheet) and the 10 meas you multiply the result of that by 10. So, 900/700= 1.29, just as you say; Log(1.29) = 0.109 10*Log(1.29) = 1.09. Seemples. David.
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Posted By: S360
Date Posted: 16 September 2018 at 10:04am
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Hi Alfie, I would like to ask you why do you take for granted that the relationship between dBfs and DBu is proportional on the Dcx. Im working with this proccesor and with de Drive Rack Pa2 (dBx) and at least in the dBx they provide you this information:
As you can see the relationship between dBfs and dBu is not proportional, I`ve tried to find this information on the Dcx manual but behringer doesn`t bring it. Don`t now what to do O.o' Thanks in advance, S360
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Posted By: suparub
Date Posted: 06 August 2019 at 8:40am
| up :) |