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Title: Any first time cautions w/ Danley TH Mini + Crown XLS2500 combo?
Post by: Wayne Smith2 on May 30, 2019, 07:24:00 PM
This would be a first time out with the Mini running on this Crown - or bridging this amp. Looks straight forward enough, I just wanted to get a cross check here.
High and Low pass filtering will happen upstream rather than the amp's filters.
Thanks
Title: Re: Any first time cautions w/ Danley TH Mini + Crown XLS2500 combo?
Post by: Frank Koenig on May 30, 2019, 09:08:27 PM
This would be a first time out with the Mini running on this Crown - or bridging this amp. Looks straight forward enough, I just wanted to get a cross check here.
High and Low pass filtering will happen upstream rather than the amp's filters.
Thanks

I doesn't matter where in the signal path those filters are so long as they are there. I would follow Danley's guidance on the high-pass. That driver is rated at 700 W AES, as I recall, so I wouldn't set your average power limiter any higher than 700/3 or 233 W. When the police show up the second time because of bass complaints -- relent  ;D  --Frank
Title: Re: Any first time cautions w/ Danley TH Mini + Crown XLS2500 combo?
Post by: Neale Watson on May 31, 2019, 05:46:26 AM
I wouldn't set your average power limiter any higher than 700/3 or 233 W
^^^
this
Title: Re: Any first time cautions w/ Danley TH Mini + Crown XLS2500 combo?
Post by: Steve Crump on May 31, 2019, 12:11:56 PM
I wouldn't set your average power limiter any higher than 700/3 or 233 W.


Frank,


I need educating here. Why do you pick 1/3 of the continuous rating for the average power limiter setting? I understand that you are protecting the driver, but couldn't the driver with that rating safely handle a higher average. My main reason for asking is that I am about to pull out some of my gear and make some changes to the amp configuration and I will be setting up limiters during this process and now I am questioning my original setup.


Thanks,

Steve
Title: Re: Any first time cautions w/ Danley TH Mini + Crown XLS2500 combo?
Post by: Wayne Smith2 on May 31, 2019, 03:17:43 PM
I was going to follow these two guide points from Danley--
'TH Mini - 700 watts continuous 1400 program' (..add, in another part of the spec they use '700 continuous 2800 peak)
and
 "We recommend choosing an amp that is rated no less than continuous and no higher than program. "
The XLS2500 seems to drop right in there at 1500/8ohms bridged.
I won't have a limiter but neither will it be called to go anywhere near max.
Title: Re: Any first time cautions w/ Danley TH Mini + Crown XLS2500 combo?
Post by: Frank Koenig on May 31, 2019, 05:11:48 PM
Why do you pick 1/3 of the continuous rating for the average power limiter setting?

Steve,

The AES power /3 guidance comes from Powersoft. I've heard others suggest AES power /2, but why look for trouble? Powersoft also has suggestions for time constants based on type of driver and the size of the voice coil. I'd reproduce it here but don't want to run afoul of fair use. Go to the Powersoft Website and download any of their amplifier user manuals, I think it's in all of them.

Be mindful that there are different kinds of average power limiters. Some measure true power (integrate v*i over time) while others use RMS voltage as a proxy. If each amplifier channel powers only a single driver, the true power limiter is the most accurate. If an amplifier channel powers multiple drivers in parallel, then RMS voltage should be used as otherwise one driver going open-circuit will make more power available to the remaining drivers -- not good. You must take the driver impedance into account when using an RMS voltage limiter. If in doubt, measure with the amplifier open circuited.

Ideally we'd measure the voice coil temperature directly and avoid all this nonsense. I assume some of the better integrated system makers use a more sophisticated predictive thermal model of the driver to do their limiting. I've got some ideas on the subject but I'll put them in a separate post under Audio Measurement and Testing.

--Frank
Title: Re: Any first time cautions w/ Danley TH Mini + Crown XLS2500 combo?
Post by: Frank Koenig on May 31, 2019, 05:33:13 PM
I won't have a limiter but neither will it be called to go anywhere near max.

Peak voltage limiters are not for normal operation but to guard against accidents like dropped mics and phantom power pops. They might also serve as a warning that you are on the verge of clipping, which is not normal operation, or shouldn't be anyway. --Frank
Title: Re: Any first time cautions w/ Danley TH Mini + Crown XLS2500 combo?
Post by: Ivan Beaver on May 31, 2019, 07:58:05 PM
Steve,

The AES power /3 guidance comes from Powersoft. I've heard others suggest AES power /2, but why look for trouble? Powersoft also has suggestions for time constants based on type of driver and the size of the voice coil. I'd reproduce it here but don't want to run afoul of fair use. Go to the Powersoft Website and download any of their amplifier user manuals, I think it's in all of them.


I used to be in the 1/2 continuous power for a thermal limit.

But after seeing to many drivers burnt with that setting, I now recommend 1/4 continuous power.  Or 6dB down.

I do agree with different attack times for different size voice coils/different power ratings.  What burns coils is energy over time, and larger coils can take more energy than smaller ones.

The power ratings are often misunderstood.  They are NOT continuous, they are for a specific signal for a specific time.  As soon as either changes, the ratings change-higher or lower.

Regarding attack time, it is important to understand how the particular limiters are reacting. 

For thermal protection, the attack time needs to be in seconds, not milliseconds.

But it depends.  In my opinion, a proper limiter should start to engage as soon as the threshold, and the time constant is how long it takes to bring the signal down to the threshod. 

One particular brand of amps have the thermal where it does nothing, until the time constant has been exceeded, and then it starts to bring it down.

I disagree with this, but that is my opinion.  While it can allow more short term peaks, I don't think it offers the protection needed.  So whenever I have to use these limiters, I set them even lower than I normally would.

Limiting is a complicated subject, with a lot of variables, and one answer does not fit all applications. 

I will use different limiter settings if I know specific program materials.  Some to allow more peaks, others for shear "idiot" protection.  Often this depends on the operator.
Title: Re: Any first time cautions w/ Danley TH Mini + Crown XLS2500 combo?
Post by: Neale Watson on May 31, 2019, 09:00:43 PM

... I won't have a limiter but neither will it be called to go anywhere near max.

Wayne - I tried this using a Powersoft M30 (similar rating) and surprisingly fried the TH-Mini driver pretty quickly.  I didn't think we were rockin' at the time
Title: Re: Any first time cautions w/ Danley TH Mini + Crown XLS2500 combo?
Post by: Wayne Smith2 on June 01, 2019, 07:47:46 PM
It came to me a little later, how on earth did I (we?) ever make it through the last 40 years in audio with w/o limiters?
:>)
Title: Re: Any first time cautions w/ Danley TH Mini + Crown XLS2500 combo?
Post by: Chris Hindle on June 01, 2019, 08:17:19 PM
It came to me a little later, how on earth did I (we?) ever make it through the last 40 years in audio with w/o limiters?
:>)
Cost of "education" was a toasted driver now and then.
You learn real quick when "enough is enough".....
Chris.
Title: Re: Any first time cautions w/ Danley TH Mini + Crown XLS2500 combo?
Post by: Tim McCulloch on June 01, 2019, 09:20:40 PM
Wayne - I tried this using a Powersoft M30 (similar rating) and surprisingly fried the TH-Mini driver pretty quickly.  I didn't think we were rockin' at the time

Too tightly limited and never coming out of limit means a mostly continuous voltage being applied to the voice coil.  With live music the duty cycle is fairly low and voice coils have some thermal recovery time; that's what isn't there in a too-tight "protection" system.  if you got the coil sufficiently hot for long enough it was a certain failure.

It came to me a little later, how on earth did I (we?) ever make it through the last 40 years in audio with w/o limiters?
:>)
Cost of "education" was a toasted driver now and then.
You learn real quick when "enough is enough".....
Chris.
What Chris said.  Blown compression driver diaphragms, torn up 18s, shredded lows... those were the cost of tuition at the Ye Olde Skool of Harde Knox.  You learned what a system under stress sounded like, each pass band of it.  You developed a concept of time, i.e. "if they finish on time, it will survive; if they play a double encore the 15s are toast".  "Amp is staying in clip longer, gotta get that down or next will be output transistors and protect lights."

This is one of the reasons I say it's a great time to be in audio.  A self powered system will do what it does and that's it.  Sure, it might sound nasty when the all warning lights are on but there's a good chance it will live to see another gig if the issue is addressed quickly.  You can still break it but it takes more persistence...
Title: Re: Any first time cautions w/ Danley TH Mini + Crown XLS2500 combo?
Post by: Steve Crump on June 01, 2019, 09:27:15 PM
Wayne - I tried this using a Powersoft M30 (similar rating) and surprisingly fried the TH-Mini driver pretty quickly.  I didn't think we were rockin' at the time

I may be looking at the wrong spec sheets, but it seems the M30 is twice the power that the XLS2500 offers. Correct me if I am wrong.
Title: Re: Any first time cautions w/ Danley TH Mini + Crown XLS2500 combo?
Post by: Steve Crump on June 01, 2019, 09:57:13 PM
Frank and or Ivan,

At the risk of hijacking this post, is “continuous” and “long term” speaker rating considered the same? I am reading the manual on the Crown Macro Tech I series that I am using and Crown uses the term “long term” and the manufacture of the speaker states “continuous” and I just want to make sure I have an understanding.

Thanks,

Steve
Title: Re: Any first time cautions w/ Danley TH Mini + Crown XLS2500 combo?
Post by: Wayne Smith2 on June 02, 2019, 01:34:48 AM
I may be looking at the wrong spec sheets, but it seems the M30 is twice the power that the XLS2500 offers. Correct me if I am wrong.
Assuming I'm reading -and applying- the specs correctly 'apples to apples', I'm seeing the M30 3000 watts bridged at 8 ohms?
My previous config has been a pair of EV ZX3-90s and the TH Mini sharing a single QSC 1804 -leaving both slightly under powered.
Title: Re: Any first time cautions w/ Danley TH Mini + Crown XLS2500 combo?
Post by: Wayne Smith2 on June 02, 2019, 01:49:32 AM
Frank and or Ivan,

At the risk of hijacking this post, is “continuous” and “long term” speaker rating considered the same? I am reading the manual on the Crown Macro Tech I series that I am using and Crown uses the term “long term” and the manufacture of the speaker states “continuous” and I just want to make sure I have an understanding.

Thanks,

Steve

And I'm taking this from another Danley spec, and Ivan's previous post to hart. "Please note “Continuous” does not mean “forever”!" . I.e. music with ebb and flow vs ..well, not. :>)
Title: Re: Any first time cautions w/ Danley TH Mini + Crown XLS2500 combo?
Post by: Chris Hindle on June 02, 2019, 06:49:46 AM
.  You developed a concept of time, i.e. "if they finish on time, it will survive; if they play a double encore the 15s are toast".  "Amp is staying in clip longer, gotta get that down or next will be output transistors and protect lights."


Back in Flame Linear and DC300A dayz, it was rather obvious when an amp was unhappy..... didn't need no stinking "protect" lighty thingy's.
Usually cost a string of drivers too.

Today's youngins have life way too easy.
Hey, I'm old, but I'm not obsolete.
My first PA was a Bogen CHB50, and a couple of Geloso columns.
4 4x8 drivers, in a 5 high "line array" "box"
Chris.
Title: Re: Any first time cautions w/ Danley TH Mini + Crown XLS2500 combo?
Post by: Ivan Beaver on June 02, 2019, 08:44:23 AM
My first PA was a Bogen CHB50,
I had a CHB50 that I used as a guitar amp, but replaced the 6L6s with 5881s.
Title: Re: Any first time cautions w/ Danley TH Mini + Crown XLS2500 combo?
Post by: Lee Douglas on June 02, 2019, 10:27:32 AM
It came to me a little later, how on earth did I (we?) ever make it through the last 40 years in audio with w/o limiters?
:>)

Cost of "education" was a toasted driver now and then.
You learn real quick when "enough is enough".....
Chris.

We were also on a first name basis with a local speaker reconing guy and had him on speed dial as we called upon him often!  Or we learned how to do it in house.
Title: Re: Any first time cautions w/ Danley TH Mini + Crown XLS2500 combo?
Post by: Steve Crump on June 02, 2019, 01:07:04 PM
Assuming I'm reading -and applying- the specs correctly 'apples to apples', I'm seeing the M30 3000 watts bridged at 8 ohms?
My previous config has been a pair of EV ZX3-90s and the TH Mini sharing a single QSC 1804 -leaving both slightly under powered.

Yeah, I read it the same as you. I used the Crown XLS2500 bridged to power a Yorkville UCS1 and never had any issues. The first year I had this setup, (because I didn’t know better), I never even turned on the clip limiters. The Yorkville wasn’t rated as high as the TH Mini, at least according to the info on the net. This was used for live music and back ground music for events. No DJing, EDM, etc...
Title: Re: Any first time cautions w/ Danley TH Mini + Crown XLS2500 combo?
Post by: Steve Crump on June 02, 2019, 01:42:23 PM

And I'm taking this from another Danley spec, and Ivan's previous post to hart. "Please note “Continuous” does not mean “forever”!" . I.e. music with ebb and flow vs ..well, not. :>)

I am a weekend warrior, definitely have a lot of knowledge to gain. Most of my knowledge I have gathered from trial and error, (lots of error) and reading info on this forum, or reading articles and manuals. But, it is sinking in...lol.

When I read the post here it started me second guessing my setup. I haven’t lost any drivers due to overheating and would rather not, but I really want to get the most of the system when I am working outdoors. That is the reason for my questions. I assume continuous and long term are basically the same, I just wanted to make sure that there wasn’t a difference that I wasn’t aware of. Long term may be a little more relevant because it doesn’t imply forever. I completely understand that some types of shows push the system harder than others. I think what is relevant to me is the statement Tim made in this post, live music has a fairly low duty cycle and that probably is why I have had no issues.

The Crown amp manual that I have states to enter the long term rating of the driver into the RMS Power Limiter value. I think it is just a question at this point if I am willing to accept a higher level of risk, based on which factor I decide to enter into the amp’s limiter. I will say after reading all this it will make me more cautious if I ever do any other type of show or material.

Back to your original post. I think you will be fine with the XLS2500 based on my experience with those amps. I have (4) and have used them for (7) years. About a year ago I lost one at a show running monitors. It blew before the show.
Title: Re: Any first time cautions w/ Danley TH Mini + Crown XLS2500 combo?
Post by: Frank Koenig on June 02, 2019, 05:06:45 PM
Frank and or Ivan,

At the risk of hijacking this post, is “continuous” and “long term” speaker rating considered the same? I am reading the manual on the Crown Macro Tech I series that I am using and Crown uses the term “long term” and the manufacture of the speaker states “continuous” and I just want to make sure I have an understanding.

Thanks,

Steve

I'll take a crack at this mostly by summarizing stuff I've learned on this forum. There are folks here vastly more experienced than I so I ask them to comment on and correct the following.
 
AES Power

"AES Power" is a standard for speaker input power rating. It was taken up by ANSI, too. It says nothing about how a speaker sounds at high power, it only represents conditions under which immediate destruction will not occur. In a nutshell, it is the maximum mean-square voltage divided by the speaker's minimum impedance, of 6 dB crest-factor pink noise band-limited to one octave that the speaker can withstand for 2 hours without certain physical parameters changing by more than 10%. The octave band is chosen to be within the normal operating frequency range of the speaker. It's a pretty brutal test and is sometimes referred to as "continuous power".

Amplifier Sizing

A rule-of-thumb for the minimum amplifier power to fully utilize the capability of a speaker is that the amplifier should be capable of sufficient voltage and current, at least short term, to drive the speaker to the peak of a sine wave of twice the AES power (not that you would want actually to run a sine wave at this power very long). This sometimes is referred to as "program power". For certain speakers and high crest factor program (hf bands) it may be advantageous to have even a little more headroom -- it's just a rule-of-thumb.

Limiter Settings

The best limiter settings are likely the ones baked into a powered speaker or integrated system by a major manufacturer with heavy R&D. When left to my own devices, I follow the Powersoft guidance which has us set the average power limiter to 1/3 AES power and the peak voltage limiter to the peak voltage of a sine wave of 2 x AES power -- same as minimum amplifier power.

The average power limiter serves to prevent smoking the voice coil, for which it should do a pretty good job assuming the time constants are chosen accurately to model the thermal behavior. But there are variables that are not accounted for and perhaps some real speaker designers can elucidate. On the other hand, I'm guessing the actual volume, in dB, left on the table by not having a fancy thermal model does not amount to much. Just get more rig. It will sound better anyway. 

The peak voltage limiter serves as a proxy for an excursion limiter and, in its simplest, frequency-blind form, does a lousy job. The problem is that excursion generally goes up with decreasing frequency and gets complicated around the box resonance frequency of a bass-reflex speaker. If we open up the limiter to get the full capability at high frequencies we run the risk of over-excursion at low frequencies. If we protect from over-excursion at low frequencies (around the upper impedance peak of a bass-reflex speaker, for example) then we're not fully utilizing the speaker at high frequencies. Some limiters allow for frequency-dependent peak limiting but I don't have any advice on how to set those up -- yet.

--Frank
Title: Re: Any first time cautions w/ Danley TH Mini + Crown XLS2500 combo?
Post by: Ivan Beaver on June 02, 2019, 06:25:35 PM
It came to me a little later, how on earth did I (we?) ever make it through the last 40 years in audio with w/o limiters?
:>)
Because we used to actually PAY ATTENTION to the amps and how hard the sound system was pushed.

Sadly today more people either don't understand or simply don't care, or don't know enough.

People are often looking for the "magic bullet", instead of being responsible.
Title: Re: Any first time cautions w/ Danley TH Mini + Crown XLS2500 combo?
Post by: Ivan Beaver on June 02, 2019, 06:29:41 PM
Frank and or Ivan,

At the risk of hijacking this post, is “continuous” and “long term” speaker rating considered the same? I am reading the manual on the Crown Macro Tech I series that I am using and Crown uses the term “long term” and the manufacture of the speaker states “continuous” and I just want to make sure I have an understanding.

Thanks,

Steve
A lot of it is a matter of terminology and different people have different ideas of the same thing.

Of course this is a reason you should use the recommended amplifiers and not try to figure out what other manufacturers are saying.

Also remember that different limiters (especially thermal or heat limiters), can react very differently.

Sometimes the "automatic" limiters can act weird or not as expected.
Title: Re: Any first time cautions w/ Danley TH Mini + Crown XLS2500 combo?
Post by: Steve Crump on June 02, 2019, 09:17:30 PM
Thank you Frank for all your input and I think I am going to re-think my setup based on your info.

Thanks, Steve
Title: Re: Any first time cautions w/ Danley TH Mini + Crown XLS2500 combo?
Post by: Steve Crump on June 02, 2019, 09:27:24 PM
Of course this is a reason you should use the recommended amplifiers and not try to figure out what other manufacturers are saying.

Ivan,

Thanks for your input, it is appreciated and valued.