Limiter settings for macrotech 3600

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   Hi all,

Just purchased a ma3600 with no clp-pip card installed. The idea was that a bit of headroom on the 1850 would be better for transients but now ive realised the 3600s have a bit of a reputation for frying drivers and would suit someone with more professional level of knowledge than my limited understanding of signal processing.  Can anyone point me in the right direction of what precautions i can take to keep the drivers protected?

Planning on using this week in 8ohm stereo so 965 watts a channel using pd 1850s in a cva reflex cab.
Through a dcx2496, crossed at 90-100hz
For tops ma2400 running 8ohm stereo of 520watts a channel to a pair of Turbo TXD 15s rated at 300rms each. All playing compressed dance music off of a 13a ring. 

I wont be able to monitor the system the whole night either so the most bullet proof setup is ideal, and ideally i would keep the amp outputs completely open incase djs try to turn them up some. Sorry if this seems really basic or has already been covered but im still scratching my head a bit after reading what i can. Would greatly appreciate any advice on how i can set these up with the correct limiter/gain settings that the drivers are as safe as possible? 
Many thanks in advance.

Edited by Shadmank - 12 September 2019 at 7:33pm

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Shadmank Members Profile Send Private Message Find Members Posts Add to Buddy List Registered User Joined: 01 July 2012 Status: Offline Points: 17	Post Options Post Reply Quote Shadmank Report Post Thanks(0) Quote Reply Topic: Limiter settings for macrotech 3600 Posted: 12 September 2019 at 6:58pm
	Hi all, Just purchased a ma3600 with no clp-pip card installed. The idea was that a bit of headroom on the 1850 would be better for transients but now ive realised the 3600s have a bit of a reputation for frying drivers and would suit someone with more professional level of knowledge than my limited understanding of signal processing. Can anyone point me in the right direction of what precautions i can take to keep the drivers protected? Planning on using this week in 8ohm stereo so 965 watts a channel using pd 1850s in a cva reflex cab. Through a dcx2496, crossed at 90-100hz For tops ma2400 running 8ohm stereo of 520watts a channel to a pair of Turbo TXD 15s rated at 300rms each. All playing compressed dance music off of a 13a ring. I wont be able to monitor the system the whole night either so the most bullet proof setup is ideal, and ideally i would keep the amp outputs completely open incase djs try to turn them up some. Sorry if this seems really basic or has already been covered but im still scratching my head a bit after reading what i can. Would greatly appreciate any advice on how i can set these up with the correct limiter/gain settings that the drivers are as safe as possible? Many thanks in advance. Edited by Shadmank - 12 September 2019 at 7:33pm

Shadmank Members Profile Send Private Message Find Members Posts Add to Buddy List Registered User Joined: 01 July 2012 Status: Offline Points: 17	Post Options Post Reply Quote Shadmank Report Post Thanks(0) Quote Reply Posted: 12 September 2019 at 7:31pm
	Current setup of kit as it stands (for 2 small rooms) Setup 1) Various DJ controllers Denon 2ch mixer Dcx2984 MA2400 at 8r stereo (520 watts pc) into 2x Turbosound TXD15 (300rms each, 600 peak) MA3600 at 8r stereo (965 watts pc) 1x reflex cab with PD 1850 (800 rms) Setup 2) 2x CDJs Pioneer DJM 600 DBX 233XS comp/limiter DOD 834 crossover (crossed at 90hz) MA 2400 at 8r bridged into 1x reflex with 1850 2x active 600 rms full range tops

Elliot Thompson Members Profile Send Private Message Find Members Posts Add to Buddy List Old Croc Joined: 02 April 2004 Location: United States Status: Offline Points: 5174	Post Options Post Reply Quote Elliot Thompson Report Post Thanks(0) Quote Reply Posted: 12 September 2019 at 9:03pm
	Since you are operating the amplifier at 8 ohms per channel, the simplest way of preventing the amplifier from clipping is to Disconnect the loudspeakers Increase the input gains on the amplifier to full Feed the amplifier a signal until it clips (Use one your music tracks) Use the Behringer to limit signal until the lights on the amplifier does not blink brightly Turn down the input gains on the amplifier and, reconnect your speakers. Best Regards,
	Elliot Thompson

Shadmank Members Profile Send Private Message Find Members Posts Add to Buddy List Registered User Joined: 01 July 2012 Status: Offline Points: 17	Post Options Post Reply Quote Shadmank Report Post Thanks(0) Quote Reply Posted: 12 September 2019 at 11:37pm
	Thanks, thats what i was planning on trying to do but wasnt sure if it would be reliable! Another issue is IIRC the macro doesnt have a clip light, the IOC only shows when the signal is distorting above 0.05%, so would this method still be effective or would it lead to excessively limiting the signal? Also am i right in thinking that if a signal is played that causes the limiter to dig in continuously then the compressed signal can cause voice coils to overheat, so do i need to learn the maths and calculate a gain structure to address this? Many thanks

Elliot Thompson Members Profile Send Private Message Find Members Posts Add to Buddy List Old Croc Joined: 02 April 2004 Location: United States Status: Offline Points: 5174	Post Options Post Reply Quote Elliot Thompson Report Post Thanks(0) Quote Reply Posted: 13 September 2019 at 2:25am
	The Input-Output-Comparator (IOC) monitors the input signal coming from the source and, the output signal from the amplifier. If there is a deviation amongst the two signals at/above 0.05% THD, the IOC indicator will flash brightly. This is Crown's method of a Clip Indicator on the Macro-Tech Series. This method stems from a time when the lowest percentage of Total Harmonic Distortion at the rated wattage was a huge selling point. This is why Crown (decades ago) would guarantee their amplifiers will always meet their advertised wattage. As you might have guessed, the amplifier's wattage is underrated and, will deliver more wattage under the standard 1% THD method listed by most, if not all amplifier manufactures today in terms of wattage. If you are concerned about an abusive DJ, this is what I would do. Max out the DJ mixer (Master at Maximum, Input Fader at Maximum) Use the Input levels of the Behringer (Most LMS offer an input level control that will offer a -40 dB) and reduce input level. By doing the above, this will offer two stages of overload prevention to the amplifier. The first stage will prevent the DJ Mixer's master output level from clamping down on the Limiter (all courtesy of the Input Levels of the Behringer LMS). The second stage (The Limiter controls of the Behringer LMS) will offer an additional prevention if the DJ tries to get more volume out of your kit by increasing the High, Mid and, Low equaliser on the DJ Mixer to max. Just make sure you password lock the Behringer to prevent any curious fingers from altercating the settings. Best Regards,
	Elliot Thompson

kedwardsleisure Members Profile Send Private Message Find Members Posts Add to Buddy List Old Croc Joined: 20 January 2009 Location: Staffordshire Status: Offline Points: 4947	Post Options Post Reply Quote kedwardsleisure Report Post Thanks(0) Quote Reply Posted: 13 September 2019 at 8:32am
	i would do as above. When the macrotechs were designed there weren't many amps on the market that had built-in clip limiters at all, at least not in UK markets. I think the first one I saw was the Cloud CV1000 and even that had a switch on the back so you could turn it off
	Kevin North Staffordshire