If you guy's are going to try to reverse engineer this... good luck ;-) Order your favorite CAD program now. I recommend SoundEasy (~$210).
Check this site for lots of free programs. Some are Excel spreadsheets some are real software.
http://www.pvconsultants.com/audio/frdgroup.htm
Especially checkout the BDS (Baffle Diffraction Simulator) and the FRC (Frequency Response Combiner) there is another one for editing graphs that is very usefull but I can't remember what it is called.
I assume the drivers are recessed because it would be too hard to flush mount them to the granite from the front. It doesn't seem to be done for time alignment as it looks like they are all at the same depth. At least that's what it looks like from the pics.
The raw response of that tweeter must be nasty with that much recess. Same for the 5"er.
Question: Do you think they are talking about 1st order acoustic slopes or 1st order electrical?
Normally crossovers are referenced to the acoustic slope so that's what I am assuming. Very tough to do. But then again it's a $40k speaker.
I can't wait to see what kind of info Nelson and companty share with us.
Russ
Check this site for lots of free programs. Some are Excel spreadsheets some are real software.
http://www.pvconsultants.com/audio/frdgroup.htm
Especially checkout the BDS (Baffle Diffraction Simulator) and the FRC (Frequency Response Combiner) there is another one for editing graphs that is very usefull but I can't remember what it is called.
I assume the drivers are recessed because it would be too hard to flush mount them to the granite from the front. It doesn't seem to be done for time alignment as it looks like they are all at the same depth. At least that's what it looks like from the pics.
The raw response of that tweeter must be nasty with that much recess. Same for the 5"er.
Question: Do you think they are talking about 1st order acoustic slopes or 1st order electrical?
Normally crossovers are referenced to the acoustic slope so that's what I am assuming. Very tough to do. But then again it's a $40k speaker.
I can't wait to see what kind of info Nelson and companty share with us.
Russ
Re: You don't see frames because they are covered by the baffle
Yeah, I posted that before I noticed they were recessed. We'll just blame it on a crappy video card ;-)
I still don't think it's a PHL. Still looking for a pic of the PSL.
Actually, now that I'm on a better computer, it looks like the mounting depth for the drivers is different.
Russ
Yeah, I posted that before I noticed they were recessed. We'll just blame it on a crappy video card ;-)
I still don't think it's a PHL. Still looking for a pic of the PSL.
Actually, now that I'm on a better computer, it looks like the mounting depth for the drivers is different.
Russ
Congratulation
Everyone has been oohing and awing over this new piece of equipment, and trying to figure out how best to reverse engineer it. But so far no one has really said congratulations to Nelson on the launch of his new speakers, so let me be the first. I hope you every success with this new speaker and congratulations. I am sure that all of the members of this forum feel the same way!
Everyone has been oohing and awing over this new piece of equipment, and trying to figure out how best to reverse engineer it. But so far no one has really said congratulations to Nelson on the launch of his new speakers, so let me be the first. I hope you every success with this new speaker and congratulations. I am sure that all of the members of this forum feel the same way!
Crossing Ravens that high mean they last longer as crossing them low gives to large excursion frying them (which apparently happens to some people sometimes) leaving you with a hole in your wallet the size of a new Raven. At least that is what I understand. Peter will know for sure...
And yes, congrats on a very neat product well out of my reach.
And yes, congrats on a very neat product well out of my reach.
Here's the link to Ravens http://orcadesign.com/companys products/ravendrivers/raven2.html
I keep a bunch of spare aluminum elements in case I blow it again. They can be obtained from Orca very cheaply (I got mine for free). This is a good part about this tweeter. Basicaly, you can't loose it. Replacing ribbon is very easy, just removing 2 screws and that's all.
I blew mine 3 times already.
Here's PHL link http://orcadesign.com/companys products/phl/1040.html
I keep a bunch of spare aluminum elements in case I blow it again. They can be obtained from Orca very cheaply (I got mine for free). This is a good part about this tweeter. Basicaly, you can't loose it. Replacing ribbon is very easy, just removing 2 screws and that's all.
I blew mine 3 times already.
Here's PHL link http://orcadesign.com/companys products/phl/1040.html
Here's my speakers http://www.diyaudio.com/forums/showthread.php?s=&postid=47075#post47075
I'm using 3rd order filter for Raven around 7K. 2 caps roughly 5uF in series with 0.23mH inductor between to ground. Triangle has second order crosover.
I'm using 3rd order filter for Raven around 7K. 2 caps roughly 5uF in series with 0.23mH inductor between to ground. Triangle has second order crosover.
This young gentleman (his nickname is Lampje) build himself a little monitor using Raven R1 and Scanspeak. He designed the Xover himself using emulator software.
http://www.raymondaudio.nl/
Hm I'm affraid this is a bit offtopic here
http://www.raymondaudio.nl/
Hm I'm affraid this is a bit offtopic here
Hi AudioFreak,AudioFreak said:
I know that. I'm thinking why they would have a low-pass filter at 22Hz? I think Kent had a brain fart.
The cone drivers are PHL.
Nelson was there today so I was able to get his picture with him in his suit, tie, and jogging shoes. He chuckled at us already into the reverse engineering and refused to devulge the middle xover points. Come on Nelson, it's not as if I have a granite quarry at my disposal.
I would post some more pics but my delete key died on my notebook so I can't start Win2k.
I'm sending this from a cyber-cafe across from my hotel.
Rodd Yamashita
I suspect Kent (Cyclotron Guy) has been heavily involved in this project, so buy him lots of beers!!! I first supposed PHLs as they have earned the Passlabs seal of Approval, but the dust cap looked too hemispherical. I guess I was right/wrong. Don't browbeat Lord Nelson too much, Let's let him have a few secrets.....l Can't wait for more photos
12 dB/oct at 22Hz means back to plan one--my original surmise.
Many people plug Thiele-Small specifications into a computer program and think this is the response they will actually get. Not so. The flat line that the programs graph above the rolloff is bogus; only meant as a placeholder in case they need to show a hump or dip if the Q is something other than maximally flat. It is not necessarily what you're going to get. Many drivers, particularly the long throw ones, have a rising response. People plug them up and play them, then talk about what deep bass they're getting. Well...actually they're getting a lot of 100Hz. To get truly flat response, you have to hit them with a low pass filter section (generally 6 dB/oct) to bring that rising response down somewhere into the region of flat. Then add a pole or two at the frequency or your choice to produce the actual crossover frequency to the next driver up--in this case, the 11" mid-bass.
With that in mind, if the Rushmore has a 12 dB/oct lowpass at 22 Hz, it's likely that at least one of those poles is EQ, bringing the driver's response down flat. The other is going to produce a single pole rolloff as soon as the rising response quits climbing (or 2 pole, if they're both being used for EQ, but I'll assume 6 for the moment). This will be at a comparatively low frequency...perhaps 50-70Hz. The net result will be that of a 6 dB/oct crossover up until somewhere in the 500-1kHz range where the driver response starts rolling off on its own, so you'll have a compound curve.
Incidentally, I don't really intend to reverse-engineer the Rushmore <i>per se</i>. I've got more than enough on my plate already with the projects I've got slated. It's just a nice way to sharpen your wits, trying to guess at the strategy behind the pretty faceplate.
Incidentally, the too-hot-at-the-top thing is why I didn't jump on the heatsink bandwagon recently. The heatsink everyone else seemed to like looked a little tall to me. If you're running one row of devices across the heatsink, you can live with it, but if you intend to put more above that first row they won't cool as well, because the air flowing across that part of the heatsink isn't room temperature air--it's already been heated by the lower rank of devices. At low bias, it'll be all right, but at higher bias, you could punish the upper outputs. Fans will help.
Grey
Many people plug Thiele-Small specifications into a computer program and think this is the response they will actually get. Not so. The flat line that the programs graph above the rolloff is bogus; only meant as a placeholder in case they need to show a hump or dip if the Q is something other than maximally flat. It is not necessarily what you're going to get. Many drivers, particularly the long throw ones, have a rising response. People plug them up and play them, then talk about what deep bass they're getting. Well...actually they're getting a lot of 100Hz. To get truly flat response, you have to hit them with a low pass filter section (generally 6 dB/oct) to bring that rising response down somewhere into the region of flat. Then add a pole or two at the frequency or your choice to produce the actual crossover frequency to the next driver up--in this case, the 11" mid-bass.
With that in mind, if the Rushmore has a 12 dB/oct lowpass at 22 Hz, it's likely that at least one of those poles is EQ, bringing the driver's response down flat. The other is going to produce a single pole rolloff as soon as the rising response quits climbing (or 2 pole, if they're both being used for EQ, but I'll assume 6 for the moment). This will be at a comparatively low frequency...perhaps 50-70Hz. The net result will be that of a 6 dB/oct crossover up until somewhere in the 500-1kHz range where the driver response starts rolling off on its own, so you'll have a compound curve.
Incidentally, I don't really intend to reverse-engineer the Rushmore <i>per se</i>. I've got more than enough on my plate already with the projects I've got slated. It's just a nice way to sharpen your wits, trying to guess at the strategy behind the pretty faceplate.
Incidentally, the too-hot-at-the-top thing is why I didn't jump on the heatsink bandwagon recently. The heatsink everyone else seemed to like looked a little tall to me. If you're running one row of devices across the heatsink, you can live with it, but if you intend to put more above that first row they won't cool as well, because the air flowing across that part of the heatsink isn't room temperature air--it's already been heated by the lower rank of devices. At low bias, it'll be all right, but at higher bias, you could punish the upper outputs. Fans will help.
Grey
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