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#16 dakos

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Posted 17 April 2014 - 10:19 PM

I've rechecked the numbers and they seem to be good so could you please elaborate what's not working for you? Or in other words, what is your goal setting up your limiters?
Avi

#17 makis

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Posted 18 April 2014 - 07:34 PM

Well, what I want is to prevent my speakers from damaging, and have all the available RMS and PEAK power I can. I don't want my limiters predefine headroom. That's the sound guy's job. If I want headroom I'll put in the chain a compressor and get done with it. This is my point of view, it may not be perfect but it is worth it f.e when you need more SPL but you don't have more speakers  . So what if I have 12db of headroom or more? I don't want it, I want my system play loud enough for everyone to be satisfied and I get payed as promised.

#18 dakos

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Posted 19 April 2014 - 07:33 AM

I believe you're mixing the terms headroom and compression. Compression does not equal headroom!! You try to give who ever is using your rig as much headroom as they need, depending on the dynamics required by the type of music they play. When you run out of headroom and need more SPL, as a compromise you may use a compressor to lower the dynamics in the signal gracefully while lowering the headroom. Also it's much better to compress only the channel that's eating your headroom (a singer with poor technique or kick drum) and not the entire mix. I'll give you an example, if your rig is intended for a rock concert, that needs 15-20dB of headroom, you can choose to lower the headroom, compress the peaks in the music to say 12dB. This works well till a curtain point when the compression gets audible.

If you just want to protect your drivers then I believe you already have the numbers. If you want consistent SPL during your show then you need different numbers.
This is the calculation for having the peak voltage for your speakers for the itech limiters:
Peak Limiting voltage = SQ Root (Peak speaker rating * speaker impedance)
You already have the numbers for the XTi1002 from previous post.
Running your rig this way is very dangerous and I believe will not give you what you want but I might be wrong...

I'm sorry but despite my trying, I don't know what you're trying to do so I'm a bit limited in assisting you.

#19 makis

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Posted 19 April 2014 - 11:25 AM

Obviously I missexplained something. When I'm referring to a compressor I don't mean I'll compress the peaks. I'll have it set up the way you suggest set up limiters (slow attack, slow release) so I'll have pretty much the same result "Headroom". Only in this case I don't need to carry my PC with me to make a change, or change presets on every amp. I just set up a compressor correctly on the digital console's master out or even bypass it on the fly.
As for headroom sometimes where I come from no one cares about. They just want more SPL,  volume, noise how can I say it they just want MORE..
And what can I give them? Peak power or continuous power?
As for the pour technique vocals it is a very common thing but how is this going to be solved with this kind of limiters? Yes a compressor on his channel is a good thing but if you have to push his voice upper than  everything else and please don't ask why  then your limiters will engage and push everything down..There we go again not enough SPL..plus audible limiting. Tough situation but not uncommon.
I decided to have that extra 6db of vocals average and push a bit more my speakers so I won't hear complaints after show.
What would u do?

#20 dakos

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Posted 19 April 2014 - 02:42 PM

This is getting a bit more complex so I'll split my answer into a few parts...

View Postmakis, on 19 April 2014 - 11:25 AM, said:

Obviously I miss explained something. When I'm referring to a compressor I don't mean I'll compress the peaks.

My friend, if I'm not mistaking, compressing the peaks (or automatic gain control) is what compressors do. What turns a compressor into a limiter is not the attack and release times but its compression ratio being high (usually above 1:20). Attack and release times differentiate between an RMS/Continuous limiter (long times) as opposed to Peak limiter (short times).
Here are a couple of good basic guides/tutorials:
http://www.doctorpro...essors_en.shtml
http://www.rane.com/note155.html

Compression & Compression Vs Over Compression:
https://www.youtube....h?v=ZqEoTY3vCIM

A great video tutorial about compressors:
https://www.youtube....h?v=fSzG8Rl_pm0

View Postmakis, on 19 April 2014 - 11:25 AM, said:

I'll have it set up the way you suggest set up limiters (slow attack, slow release) so I'll have pretty much the same result "Headroom". Only in this case I don't need to carry my PC with me to make a change, or change presets on every amp. I just set up a compressor correctly on the digital console's master out or even bypass it on the fly.
As for headroom sometimes where I come from no one cares about. They just want more SPL, volume, noise how can I say it they just want MORE..
And what can I give them? Peak power or continuous power?
Setting up a compressor the way I suspect you plan to, just gives you fake headroom with the unwanted over compressed sound. Any way I think you're looking at this the wrong way, you can only give what you have or less, not more. If they want MORE, my guessing is that you need to GET MORE!!
If you encounter this type of need at more then 50% of your gigs then this might be the time for upgrades, so I'll ask you this:
For how many people do you usually play (80-90% of your shows)? How far is your crowd from the speakers? Indoors or outdoors? What type of music?

If you're using itechs or some other smart amp, that usually means you need a computer near by.

View Postmakis, on 19 April 2014 - 11:25 AM, said:

As for the poor technique vocals it is a very common thing but how is this going to be solved with this kind of limiters? Yes a compressor on his channel is a good thing but if you have to push his voice upper than everything else, and please don't ask why, then your limiters will engage and push everything down. There we go again not enough SPL plus audible limiting. Tough situation but not uncommon.

For every problem we encounter there is a right way and a wrong way to fix. For example the problem of a poor technique vocalist, the right way is to put a compressor only on that channel and take out let's say the top 6dB, that would take good care of the problematic channel while keeping your headroom at the amount you need for the rest of the mix. Since now nobody is eating your headroom, you will still be able to make that singer louder compared to the rest just not when he/she is shouting their lungs out. It wouldn't hurt the overall sound/balance of the whole mix therefore everything would sound as musical as it should.

Could it be that those singers just need more SPL on their stage monitors while the mix in the FOH sounds great?

View Postmakis, on 19 April 2014 - 11:25 AM, said:

I decided to have that extra 6db of vocals average and push a bit more my speakers so I won't hear complaints after show.
What would u do?

IMHO you will just hear other complaints, the way you plan on doing things you'll cripple yourself sonically, you'll run into power compression a few minutes into the show, every few minutes you'll need to push the faders just a bit more to get the proper volume your clients want, you'll end up hitting the limiters at the same volume you would have if you'd have set them to 9-12dB just with much more energy and allot more wear and tear for your gear.
Avi

#21 makis

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Posted 19 April 2014 - 05:40 PM

1) Fake headroom?
Let's say you have in frond of you a compressor and a limiter besides quality can't you set them up to do exactly the same thing? Limit? I prefer doing the job with an easily adjustable compressor on a console (or should I say limiter to be more accurate?) than buying a laptop to carry with me. I don't find any good reason not to go this way.
2) Get more? Easy to say so, not very easy to buy more or carry more. Especially when you don't need more, cause I don't for 100-200 people either in or out doors. The problem here is what singers THINK of their voice loudness and clarity in foh mix and what sound guys try to do and when they can't do it they will never say it's their fault, it's always the systems or your fault. So I tried this let the system loose, it gets pretty scary when they push a fader up and they never say I don't have enough of this. And it works. The only catch is I have to be twice alerted.
3) The most dangerous part is when they shout their lounges out. This is an all show long problem and I'm not on the console so I'll push the fader down.
As for power compression I think I've experienced this situation 1-2 times and I want to ask you after what point driving those amps and for how long I might have power compression on my speakers with these values on the limiters? How exactly is power compression connected to limit values?

#22 dakos

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Posted 19 April 2014 - 06:54 PM

View Postmakis, on 19 April 2014 - 05:40 PM, said:

1) Fake headroom?
Let's say you have in frond of you a compressor and a limiter besides quality can't you set them up to do exactly the same thing? Limit? I prefer doing the job with an easily adjustable compressor on a console (or should I say limiter to be more accurate?) than buying a laptop to carry with me. I don't find any good reason not to go this way.

I'm guessing the difference is conceptual, if you do things correctly then you shouldn't be hitting the limiters but using the compressor continuously isn't a sign you're doing something wrong. BUT, I'll read what I wrote again tomorrow after I sleep a bit, hope I won't punch myself.

View Postmakis, on 19 April 2014 - 05:40 PM, said:

2) Get more? Easy to say so, not very easy to buy more or carry more. Especially when you don't need more, cause I don't for 100-200 people either in or out doors. The problem here is what singers THINK of their voice loudness and clarity in foh mix and what sound guys try to do and when they can't do it they will never say it's their fault, it's always the systems or your fault. So I tried this let the system loose, it gets pretty scary when they push a fader up and they never say I don't have enough of this. And it works. The only catch is I have to be twice alerted.

For 100-200 people you don't need more, you should be able to make them half deaf with what you already have.

View Postmakis, on 19 April 2014 - 05:40 PM, said:

3) The most dangerous part is when they shout their lounges out. This is an all show long problem and I'm not on the console so I'll push the fader down.
As for power compression I think I've experienced this situation 1-2 times and I want to ask you after what point driving those amps and for how long I might have power compression on my speakers?

If you feed a speaker its rated RMS power, they reach their max temp (impedance) after about 30 minutes, but they reach 90-95% of that temperature after 5-6 minutes. I'm not sure at which point you experience power compression but it's between the two.

I've posted a link to a thread that contains a picture with graphs made for B&C woofer fed pink noise at its rated RMS power so you may see for yourself how fast the impedance raises (scroll down to Bennnett Prescotts forth post):
http://soundforums.n...p-speakers.html

Avi, out...

#23 dakos

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Posted 02 May 2014 - 04:16 AM

Dear Adam,
Been thinking allot what to answer you... You are correct in that if you take a compressor and configure it as a limiter and use it both conceptually and functionally as a limiter then there's no problem. If you're more comfortable keeping an additional compressor instead of a laptop than it's a winner for you. For some reason I thought you wanted to compress, not limit, the entire mix. I still wouldn't recommend you configure the limiters using the speakers absolute limitations, you'll be walking on edge with them, having very little thermal reserve in case something does happen.

So did you manage to calculate all the numbers you needed for the limiters?
Avi