![]() (YET, Thomas and Chuck are going to have one very soon.- reportedly) However, the rub is that there aren't any good diy high pass filters out there. Many of us are willing to risk our drivers and go without the highpass filters. ![]() We do this out of the belief that we have soooo much sub, and that the tuning point is so low, that there just isn't going to be much signal in that range. It may get riskier as more movies have that low freq. You just really have to pay attention to the limits of the sub. Its a gamble that I'm taking, but I can afford to replace my drivers.Īs far as if there is a science, yes. You want to have enough volume to get a nice flat response, but maybe with a little gentle roll off to allow room gain to fill in. then you need to check your port velocity and resonance. make sure you port doesn't exceed say 25 - 35m/s, and make sure the first port resonance is above say 200hz. You'll find it can be quite the balancing act sometimes. These aren't hard limits, but good guidelines.Īgain, use the export feature to save your graphs and then attach them. That said you need to remember these are anechoic sims, not how things are going to happen in-room once room-gain is taken into account Yes in theory we want to keep the black driver output line below the red line. the redline is the driver output vs frequency, for just the driver. The black line just below it that dips at the box tuning frequency is the driver excursion for that power level of drive- at the Fb, the box/port combination reduces the driver excursion substantially. ![]() There are several versions of Unibox, and you won't always see the same data in the combined plots. Let's look at this one, done in Unibox 3 for an Aurasound NS12 woofer in a 75 liter box. The Legend describes the outputs for each colored trace. The dark blue is the anchoic SPL output for the combined port and speaker with 100W drive. In the room, this is modified by near by boundary placement, and in the lower frequencies may reach a level 6 dB or more higher. This is why this system is designed and tuned with a drop off toward lower frequencies, with lower Q, so that the transient response is tighter and the in room balance with proper placement will be perceived as relatively flat, not as bass heavy. The Red line is the maximum SPL that can be produced directly by the driver with 10 mm peak excursion. The thin black line with the dip at box tuning is the SPL produced by the driver in this box with 100W drive. At the box tuning, most of the output is coming from the port- one reason why you DON'T want to cheese out on the port diameter and impair the clean output capability. The upper light blue plot trace is the SPL produced by the port. The lower green-blue trace is the estimated output due to leaks. The light gray trace is the maximum SPL that can be produced (anehoic) by this cabinet, driver and port combination when driven to 10 mm excursion. This is not a frequency response versus input per se, but a maximum output capability of the speaker and cabinet combination at maximum Xmax.I've heard really good things about In your case though, I'd just advise picking up a book and a copy of excel and working through the math yourself. I should have said that I'm doing this on the cheap, so I'm looking for freeware.Īs far as hitting xmax. there's a difference between steady state and peak analysis. If you're putting say, 100 watts RMS into the driver, that means that you're hitting voltage and hence excursion peaks above and below that nominal level. Perhaps the software you're using is providing averaged excursion on it's xmax graph, instead of peak. In both WinISD pro and unibox the excursion chart is for a given level of power. I just adjusted the power until there was a frequency at which the driver reaches its xmax. so are you using the equivalently tuned port? The freeware ISD doesn't model PR specificly. I'm going to solve my problem by simply buying a larger driver that I know my amp cannot push to its limit, then adjust the mass of my PR to get the response I want. ![]() Jason - I'm using a 10" driver whith 16.5mm of one way throw (according to the manufacturer). The PR is a 15" unit with 31mm of one way throw. Mcylinder - I think you are right, the manufacturer was probably optimistic about the xmax of the driver (it is a Blueprint 1001, not available anymore). ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |