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Posts by catapult

I disagree. A good dipole like JohnK's NaO Note has much better constant directivity than any of Earl's designs. The dipole's CD extends down into the bass while Earl doesn't get any CD below 1K. Of course Earl counters that the dipole's CD isn't narrow enough (-6dB at 60 degrees vs. 45 degrees) and the midrange/bass stuff doesn't matter anyway. Experts disagree on what's most important. Shrug.Edit: my take, if you need it loud, with a big dynamic range, build a waveguide...
Actually, it's sealed boxes that need EQ. Plugging your numbers into ISD online, your box is -3dB at 50Hz and -15dB at 20Hz. No wonder you're disappointed with its performance as a sub. Don't blame the amp, don't blame the driver, blame the designer. EQ it flat down to 20Hz and get back to us.Edit: in case you missed the point of my smartass reply, you need an EQ. There's nothing wrong with the sub you have built but it needs an EQ to sound right. No need to build a new...
Dang, you're right! Oh well, so much for that plan.
Okay, here's something like how it might work. Input: high shelving, 1.3K, -2dB Tweeter: high shelving, 10K, -2dB Woofer: low shelving, 100, +2dB Note that you have to boost the low end of the woofer rather than cutting its high end. That's because the upper end of the woofer isn't changed much by the input filter and you need to match up to that. You'd need a pretty low ratio as the total gain of each filter is only 2 dB and you'd probably want it to kick in...
Ahhhh -- serious brain fart on my part! It will be complicated but you can set up 3 dynamic filters, one on the input and one on each driver. So, you should be able to get it done with shelving filters. Highest one on the tweeter Lowest one on the woofer Middle one on the input, affecting both drivers Pick a non-dynamic EQ tab to visualize the 3 filters summed and get an idea of the frequencies and gains you want.
Do you have the software? The curves pretty much show what's going on. Set the (max) filter on the first tab and set the threshold and ratio on the second tab. Play with different values to get an idea what's going on. The horizontal axis is the input dB at the filter's frequency and the vertical axis is the output at that frequency. For a -5dB filter maybe start with -15dB and 1.8. Then change them depending on where and how fast you want it to kick in. An infinite...
I don't think you can get there with a single shelving filter. That's over 6 octaves and the shelving filter will cover at most a couple of octaves. Manually, you could set several filters at different frequencies and get it done but the dynamic thing only lets you set one filter. Maybe you could save a 'loud' house curve to a separate memory and use it when you need it?
Different strokes, Penn. I'm just trying to be a voice of reason here. I figure a system is no better than its weakest link and that's often the performance of the woofer at the lowest frequency it's asked to play. Sure all that high frequency efficiency is a nice bonus but you can't get around the pesky physics on the low end. Once you get down around 80 Hz, there isn't much difference in efficiency or max SPL between the pro drivers and the others. That said, I love pro...
Penn, I can't argue with your personal subjective experience. The objective fact is that a pair of Dayton RS225 and a single TD12M run out of gas (excursion) at the same SPL at 60 Hz or below. And there isn't a 12" made that's anywhere near 95dB down that low so that's a straw man. I picked the M version because it's often claimed that an econowave-style 2-way is superior to any "hifi" speaker and the S version isn't really suitable for a 2-way. Have you ever heard the...
Okay, let's put some numbers to it. What's the max SPL of a pair of RS225 (Statements) vs. a single TD12M. The TD12M should stomp all over the Daytons because it can handle more power, right? Nope, depending on where you cross to the sub. They're both excursion limited down low and that's what determines the the max SPL of the system. Crossing at 60Hz or below, the performance is almost identical. Crossing at 80, the TD12M has a 3dB advantage and above there the advantage...
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