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3x12+2"wNL8's&4Xti4000's
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<blockquote data-quote="Ivan Beaver" data-source="post: 50282" data-attributes="member: 30"><p>Re: 3x12+2"wNL8's&4Xti4000's</p><p></p><p></p><p></p><p>Yes you do have to "get rid" of that voltage going to the HF device-because the HF device has a much greater sensitivity (and lower "power" capacity) than the woofer.</p><p></p><p>If you do it "up stream" via EQ (which is one way to do it), you have to assume that the user will do it properly- and not screw it up. Remember we are talking aobut sounds guys here whom many just HAVE to pee on the tires-to make it "better"-because THEY did it. I don't want to get started on that one.</p><p></p><p>The impedance one can be quite a bit tricky. At first glance it would seem simple enough to just use a higher impedance HF device-so that for a given input voltage the current flow would be less and therefore there would be less sound coming out of it. So far so good.</p><p></p><p>HOWEVER we have to look at bit closer at what REALLY happens-especially when you put a driver on a horn.</p><p></p><p>One of the big "unknowns/misconceptions/unspoken etc" is that simply putting a driver (compression driver-midrange-woofer etc) on a horn will make it louder. Yes it will-BUT it is not an flat "gain" across the freq range.</p><p></p><p>Let's look at just the HF (the mids and lows work the same way). Let's say a HF driver has a flat response (most are not-but let's assume so for this example). When you put the driver on a horn, you will get a hump in the response. On the top end of the response-the horn is doing little to nothing in the way of horn gain. All of the available "gain" has already happened-BEFORE the sound gets out of the HF driver. All the horn does is to control the pattern (which can result in gain-over a driver that is not on a horn). The point at which this happens is determined by the size of the driver opening (or cone diameter for lower freq). The larger the opening-the lower the point at which the horn will actually have any gain. This is part of the reason that drivers with 2" exits don't have a lot of HF (among other reasons)</p><p></p><p>So at the point at which the horn has gain-down to the point at which the exit size of the horn is not large enough-or the driver response starts to fall off-or a combination of both-the sound from the driver/horn combination will be louder.</p><p></p><p>So now we have a problem. The top end of the response is lower than the "midband" response. If we use a higher impedance driver to drop this "midband gain", then the top end is ALSO going to drop (by the same amount. So now the higher freq may not be as loud as the woofer-especially when given the reduced input signal level.</p><p></p><p>So a good passive crossover will "throw away" the extra gain of horn down low (resulting in some heat) by effectively putting a freq dependant series resistor (via the caps and coils) in line with the HF driver. </p><p></p><p>So at the top end of the response-then there is no attenuation through the crossver. So the resultant freq output is flat.</p><p></p><p>There are different ways to "skin a cat". It just depends on whether you want to do it inside the cabinet (via passive crossover or an active cabinet) where the user can't easily screw it up, or externally (bi/tri amping or eq in line with a passive "divider" inside the cabinet) in which the manufacturer HOPES that the end user doesn't try to "roll their own" design and screw up something that they don't understand.</p><p></p><p>There are advantages and disadvantages to every design-and compromises that have to be made all along the way.</p><p></p><p>As with all things-you have to look at more than one anlge to get the full "picture". That whole -simple, easy to understand wrong answer, thing.</p></blockquote><p></p>
[QUOTE="Ivan Beaver, post: 50282, member: 30"] Re: 3x12+2"wNL8's&4Xti4000's Yes you do have to "get rid" of that voltage going to the HF device-because the HF device has a much greater sensitivity (and lower "power" capacity) than the woofer. If you do it "up stream" via EQ (which is one way to do it), you have to assume that the user will do it properly- and not screw it up. Remember we are talking aobut sounds guys here whom many just HAVE to pee on the tires-to make it "better"-because THEY did it. I don't want to get started on that one. The impedance one can be quite a bit tricky. At first glance it would seem simple enough to just use a higher impedance HF device-so that for a given input voltage the current flow would be less and therefore there would be less sound coming out of it. So far so good. HOWEVER we have to look at bit closer at what REALLY happens-especially when you put a driver on a horn. One of the big "unknowns/misconceptions/unspoken etc" is that simply putting a driver (compression driver-midrange-woofer etc) on a horn will make it louder. Yes it will-BUT it is not an flat "gain" across the freq range. Let's look at just the HF (the mids and lows work the same way). Let's say a HF driver has a flat response (most are not-but let's assume so for this example). When you put the driver on a horn, you will get a hump in the response. On the top end of the response-the horn is doing little to nothing in the way of horn gain. All of the available "gain" has already happened-BEFORE the sound gets out of the HF driver. All the horn does is to control the pattern (which can result in gain-over a driver that is not on a horn). The point at which this happens is determined by the size of the driver opening (or cone diameter for lower freq). The larger the opening-the lower the point at which the horn will actually have any gain. This is part of the reason that drivers with 2" exits don't have a lot of HF (among other reasons) So at the point at which the horn has gain-down to the point at which the exit size of the horn is not large enough-or the driver response starts to fall off-or a combination of both-the sound from the driver/horn combination will be louder. So now we have a problem. The top end of the response is lower than the "midband" response. If we use a higher impedance driver to drop this "midband gain", then the top end is ALSO going to drop (by the same amount. So now the higher freq may not be as loud as the woofer-especially when given the reduced input signal level. So a good passive crossover will "throw away" the extra gain of horn down low (resulting in some heat) by effectively putting a freq dependant series resistor (via the caps and coils) in line with the HF driver. So at the top end of the response-then there is no attenuation through the crossver. So the resultant freq output is flat. There are different ways to "skin a cat". It just depends on whether you want to do it inside the cabinet (via passive crossover or an active cabinet) where the user can't easily screw it up, or externally (bi/tri amping or eq in line with a passive "divider" inside the cabinet) in which the manufacturer HOPES that the end user doesn't try to "roll their own" design and screw up something that they don't understand. There are advantages and disadvantages to every design-and compromises that have to be made all along the way. As with all things-you have to look at more than one anlge to get the full "picture". That whole -simple, easy to understand wrong answer, thing. [/QUOTE]
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