Calculating limiters |
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lost eden
Young Croc Joined: 04 April 2011 Location: Dundee Status: Offline Points: 942 |
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Thanks for the clear explanation & examples Grubbah! I had to read through it several times but I think it's finally making sense to me. Knowing that voltage gain is different depending upon load for this amp clears up a lot, but I guess if I'd thought about it I should've realised this myself by the simple fact that the rated power into different loads/bridge configurations aren't clean multiples!
I ran through the calculations again, assuming each Brooke cab on a 350W/8Ω channel & the sub on 2x channels bridged to 1000W/8Ω, I come up with this; Brooke INH-8 0.775 V input sensitivity 36.68554626329598 dB voltage gain -2.4258589405731716 dBu limiter -24.4258589405731716 dB limiter on DCX ======= PD.12SB30 0.775 V input sensitivity 41.244865819793226 dB voltage gain -3.974878540430603 dBu limiter -25.974878540430603 dB limiter on DCX ============================================== Brooke INH-8 1.4 V input sensitivity 31.549019599857427 dB voltage gain 2.7106677228653835 dBu limiter -19.2893322771346165 dB limiter on DCX (same as your example, so I think I'm doing this right!) ======= PD.12SB30 1.4 V input sensitivity 36.108339156354674 dB voltage gain 1.1616481230079492 dBu limiter -20.8383518769920508 dB limiter on DCX ============================================== So if I set the amp to 0.775V input sensitivity, I can't dial in the limiters in the DCX low enough (their range is -24dB to 0dB) & would have to use its output gains to 'make up' the discrepancy. But if I set the amp to 1.4V input sensitivity. I can dial in a -19.3dB threshold for the limiters for the Brooke's & a -20.9dB threshold for the limiter for the sub, leaving the output gains at 0dB. Correct so far? And am I right in thinking that as these limiters in the DCX are 'zero' attack, these settings will allow me to play band-limited pink noise right up to the continuous power handling of the speakers, but won't allow crests above the continuous power handling (eg the sub is rated for 1.6kW 6dB crests, but with the -20.9dB limiter any signal that would result in the amp's output to the sub going above 400W (even for a moment) will be clobbered)?
Edited by lost eden - 24 November 2014 at 7:10pm |
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junoprobelaunch
Registered User Joined: 01 April 2018 Location: Devon Status: Offline Points: 298 |
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That was literally so helpful, even four years later
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lost eden
Young Croc Joined: 04 April 2011 Location: Dundee Status: Offline Points: 942 |
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And my drivers are all still alive four years later
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bass*en*mass
Old Croc Joined: 03 September 2009 Location: "unknown" Status: Offline Points: 4009 |
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theres a simple calculator available:
works offline too.. ;)
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toastyghost
The 10,000 Points Club Joined: 09 January 2007 Location: Manchester Status: Offline Points: 10920 |
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But most boxes (or drivers) cannot handle the AES rating for any length of time so a simple calculator can lead to dead kit |
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bass*en*mass
Old Croc Joined: 03 September 2009 Location: "unknown" Status: Offline Points: 4009 |
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can, not must, as a starter it helps imo..
real world impedance in most cases is higher than nominal afaik anyways hence nominal limiting with a simple calculator seems better than no starting point :) |
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