discreet Posted November 14, 2015 Share Posted November 14, 2015 (edited) This is also in Repairs and Technical but I wanted to put it here as well as there is another 'Tweeter' thread here which may have some bearing on this one... or not. Dad has already posted useful comments in Repairs and Technical, I hope it's OK to post it here as well..? If not, delete... [b]Tweeter/Horn/Crossover Questions...[/b] [color=#282828][font=helvetica, arial, sans-serif]From what I can glean from t'interwebz, minimising tweeter activity with the LPad (the big potentiometer-type thing on the back which varies the effect of the tweeter) can produce a resistance in the circuit which manifests itself as heat in said LPad - it is possible to burn out the LPad [/font][/color][i]and [/i][color=#282828][font=helvetica, arial, sans-serif]the crossover [/font][/color][i]and [/i][color=#282828][font=helvetica, arial, sans-serif]even damage the tweeter/horn in the process. Allegedly.[/font][/color] [color=#282828][font=helvetica, arial, sans-serif]Firstly, is this really the case? And secondly if so, then should there not be a warning label on the cab to inform us of this fact? Thirdly, is it still a problem on those cabs that have an on/off switch for the tweeter/horn, or does that take it out of the circuit altogether?[/font][/color] [color=#282828][font=helvetica, arial, sans-serif]I have read on TB and elsewhere that if you have a cab with a tweeter/horn you should run the cab with the tweeter ON and make subsequent necessary tone adjustments using your amp EQ. I have a cab with a tweeter and have recently started running it with the tweeters up FULL as an experiment - and it [/font][/color][i]is [/i][color=#282828][font=helvetica, arial, sans-serif]indeed possible to make the necessary adjustments at the amp.[/font][/color] [color=#282828][font=helvetica, arial, sans-serif]In fact - in my humble opinion, this actually improves the overall sound of the cab... so fourthly, is it just my imagination, or does the cab actually sound better overall with the tweeter running, as this is how the circuit was designed to be used?[/font][/color] [color=#282828][font=helvetica, arial, sans-serif]Or fifthly, is it just silly bullplop? I thank you!! [/font][/color] [color=#282828][font=helvetica, arial, sans-serif] [/font][/color] Edited November 14, 2015 by discreet Quote Link to comment Share on other sites More sharing options...
Bill Fitzmaurice Posted November 14, 2015 Share Posted November 14, 2015 [quote name='discreet' timestamp='1447534682' post='2908453'] [color=#282828][font=helvetica, arial, sans-serif]From what I can glean from t'interwebz, minimising tweeter activity with the LPad (the big potentiometer-type thing on the back which varies the effect of the tweeter) can produce a resistance in the circuit which manifests itself as heat in said LPad - it is possible to burn out the LPad [/font][/color][i]and [/i][color=#282828][font=helvetica, arial, sans-serif]the crossover [/font][/color][i]and [/i][color=#282828][font=helvetica, arial, sans-serif]even damage the tweeter/horn in the process. Allegedly.[/quote][/font][/color] [color=#282828][font=helvetica, arial, sans-serif]Assuredly. It's rare, usually the result of inadequate slope in the high pass filter and an LPad that's undersized, but it does occur. [/font][/color] [color=#282828][font=helvetica, arial, sans-serif][quote]I have read on TB and elsewhere that if you have a cab with a tweeter/horn you should run the cab with the tweeter ON and make subsequent necessary tone adjustments using your amp EQ. I have a cab with a tweeter and have recently started running it with the tweeters up FULL as an experiment - and it [/font][/color][i]is [/i][color=#282828][font=helvetica, arial, sans-serif]indeed possible to make the necessary adjustments at the amp.[/quote][/font][/color] [color=#282828][font=helvetica, arial, sans-serif]That's why they put those knobs and sliders on the amp. However, you might find it's best to use a combination of moderate lowering of the tweeter level with the LPad along with EQ. [/font][/color] [color=#282828][font=helvetica, arial, sans-serif]Most of this issue can be traced to the use of a horn loaded tweeter that has much higher sensitivity than the woofers, and could be avoided by using a midrange with sensitivity closer to that of the woofers. This also eliminates the typical response dip in the 2kHz-3.5kHz region between where the woofers leave off and the tweeters kick in. But they're more expensive than horn loaded tweeters, as are the required crossovers, so they're rarely employed. [/font][/color] Quote Link to comment Share on other sites More sharing options...
discreet Posted November 14, 2015 Author Share Posted November 14, 2015 (edited) [quote name='Bill Fitzmaurice' timestamp='1447540002' post='2908489'] [color=#282828][font=helvetica, arial, sans-serif]Assuredly. It's rare, usually the result of inadequate slope in the high pass filter and an LPad that's undersized, but it does occur... [/font][/color][color=#282828][font=helvetica, arial, sans-serif]you might find it's best to use a combination of moderate lowering of the tweeter level with the LPad along with EQ.[/font][/color] [/quote] Thanks Bill, so it IS possible. Presumably if the tweeter level was set at, say, 50% or so as a precaution against the probability of burn-out, then it would take proportionately less extreme EQ settings to achieve the final tone. Edited November 14, 2015 by discreet Quote Link to comment Share on other sites More sharing options...
Bill Fitzmaurice Posted November 15, 2015 Share Posted November 15, 2015 [quote name='discreet' timestamp='1447541501' post='2908496'] Presumably if the tweeter level was set at, say, 50% or so as a precaution against the probability of burn-out, then it would take proportionately less extreme EQ settings to achieve the final tone. [/quote]+1. A 50% setting, which is down 4.5dB, shouldn't cause a heat issue. Where it's usually a problem is when it's turned fully or nearly fully off, and being a resistor all of the power going through it is burned off as heat. Quote Link to comment Share on other sites More sharing options...
Lo-E Posted November 15, 2015 Share Posted November 15, 2015 I agree with Bill F completely and will add that I suspect that many cabs that are built to a budget will employ L-pads that are borderline or downright underrated. Stepped attenuators or on/off switches are much better options than budget L-pads but most manufacturers build to a price point with little regard for long-term reliability. Quote Link to comment Share on other sites More sharing options...
discreet Posted November 15, 2015 Author Share Posted November 15, 2015 [quote name='Bill Fitzmaurice' timestamp='1447557629' post='2908543'] +1. A 50% setting, which is down 4.5dB, shouldn't cause a heat issue. Where it's usually a problem is when it's turned fully or nearly fully off, and being a resistor all of the power going through it is burned off as heat. [/quote] Thanks Bill, then that is what I'll do from now on. [quote name='Lo-E' timestamp='1447565541' post='2908546'] I agree with Bill F completely and will add that I suspect that many cabs that are built to a budget will employ L-pads that are borderline or downright underrated. Stepped attenuators or on/off switches are much better options than budget L-pads but most manufacturers build to a price point with little regard for long-term reliability. [/quote] Thanks... as usual you get what you pay for, I suppose... Quote Link to comment Share on other sites More sharing options...
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