Set the tube bottom down on the drill press and drill completely through from the top (in the direction of the red arrow in the attached photo). the tube will be sitting at the correct angle since the bottom is presumably cut at the proper angle. since the drill bit is perpindicular to the table on which the tube will be sitting, the hole will be at teh proper angle. all that will be necessary then will be to patch the holes where the drill cut through from the top.
Attachments
Hi Mark,
It took a great deal of will power on my part to decline your generous offer to attend this year. It was an internal debate to the end...I really wanted to attend, but realized it was premature for a public unveiling. I'm sure they would be of interest to the "brethren" as is, but you no doubt can see now why I wanted to wait.
There is little question that I will be there next year if it is at all possible...plus...I fully expect to have my table ready as well.
Consider this my request for a room reservation
Casey
edit:typo
It took a great deal of will power on my part to decline your generous offer to attend this year. It was an internal debate to the end...I really wanted to attend, but realized it was premature for a public unveiling. I'm sure they would be of interest to the "brethren" as is, but you no doubt can see now why I wanted to wait.
There is little question that I will be there next year if it is at all possible...plus...I fully expect to have my table ready as well.
Consider this my request for a room reservation
Casey
edit:typo
A slight change of plans regarding the order of my progression. Last Thur. I aquired a nice recording of the "1812 Overture" and was in the throws of aural delight listening to it. The illusion was breathtaking..full sound stage, hall ambiance, the works. Everything was just super duper until the cannons...spuh-latt. Even though I had the volume down to were I could just make out the quietest passages, the little Extremis's didn't like it...at all. What was up until that point one of the most musically satisfying illusions ever was abruptly shattered. Having an almost completed baffle and 4 10" Exodus DPL-10's was to great of a temptation. I decided right then and there I would throw what I had together, and take the baffles back out when needed.
So, I took off my temp. baffles and hauled the bass units in. I then sat the bass baffle's directly on the ribbon legs. The last 2 pieces of laminated MDF haven't been glued to the bottom of them yet so the actual height of them on the legs is just about where they are supposed to be. At this point of the assembly my always helpful brother came up with a marketing campaign...
Valveitude's
The Johnson
"Feel the POUND!!"
I then drilled some new holes and put my stinky main baffles back on (the Extremis's are not connected, they have been demoted to hole plugs...
Here's the view from the back such as it is. I don't even have my pipes bolted in...
After listenng to it for a couple of days, and trying to find the level "sweet spot" I concluded that now was as good as time as any to construct a dipole eq, and infra sonic high pass...
That's a 4-pole Butterworth highpass rolling off at 10hz, followed by a 6dB/octave eq that starts at 70hz and shelves at 20hz (approx.). This was based on the dipole sims I had done earlier. As the baffle isn't correct yet, the eq isn't quite right either...but it's close.
In spite of the lack of completion, I now have the cleanest, tightest, deepest bass I have ever had. And the 1812? I now feel the cannons, and the drivers don't bottom. I am truly ecstatic about my design choices. I don't have the bass completely isolated from the ribbons due to using the ribbon legs, but very little vibration makes it to the ribbon baffles. This cleaned up the top end significantly. The image is more precise and the attack is amazing.
You may have noticed all the CD's in the above picture...I am currently re-discovering all my music.
Folks, the sound is stunning .
Casey
Edit:typo
So, I took off my temp. baffles and hauled the bass units in. I then sat the bass baffle's directly on the ribbon legs. The last 2 pieces of laminated MDF haven't been glued to the bottom of them yet so the actual height of them on the legs is just about where they are supposed to be. At this point of the assembly my always helpful brother came up with a marketing campaign...
Valveitude's
The Johnson
"Feel the POUND!!"
I then drilled some new holes and put my stinky main baffles back on (the Extremis's are not connected, they have been demoted to hole plugs...
Here's the view from the back such as it is. I don't even have my pipes bolted in...
After listenng to it for a couple of days, and trying to find the level "sweet spot" I concluded that now was as good as time as any to construct a dipole eq, and infra sonic high pass...
That's a 4-pole Butterworth highpass rolling off at 10hz, followed by a 6dB/octave eq that starts at 70hz and shelves at 20hz (approx.). This was based on the dipole sims I had done earlier. As the baffle isn't correct yet, the eq isn't quite right either...but it's close.
In spite of the lack of completion, I now have the cleanest, tightest, deepest bass I have ever had. And the 1812? I now feel the cannons, and the drivers don't bottom. I am truly ecstatic about my design choices. I don't have the bass completely isolated from the ribbons due to using the ribbon legs, but very little vibration makes it to the ribbon baffles. This cleaned up the top end significantly. The image is more precise and the attack is amazing.
You may have noticed all the CD's in the above picture...I am currently re-discovering all my music.
Folks, the sound is stunning
.Casey
Edit:typo
Casey,
Where is all of your furniture?? What amp is that you are using in the picture?? I am very pleased you have achieved what you were after. I hope my pair turn out half as nice as those. Do you still think there might be a sweet spot in the room placement as you continue listening. Tad
Where is all of your furniture?? What amp is that you are using in the picture?? I am very pleased you have achieved what you were after. I hope my pair turn out half as nice as those. Do you still think there might be a sweet spot in the room placement as you continue listening. Tad
Outside of the picture.
The control circuitry is built into an old Kenwood chassis, the ribbons are powered with Hypex UcD modules through a resistor, and the subs are powered with surplus NHT studio monitor amps.
When i have more ambition I'll find out...at a combined weight of close to 300 lbs each you don't just slide them around. My room is pretty small so my options are limited.
Casey
Hey poopy,
Ya..they are. Beasts with finesse .
Iv'e tried up to this point to not go overboard with the "proud papa" thing, but dang...these things kick some serious but. On the pure hammer ability I can reach ear bleeding concert levels in my moderate sized room with no signs of strain at all. My 20 year old head banging son came over with a friend to check out the latest addition of the bass modules..after cranking some Drowning Pool WFO, they actually asked to turn it down . On the delicate side, musical nuances abound at normal listening levels. One example of this was when my brother, a serious Roger Waters fan, brought over one of his favorite test CD's "The Final Cut". It would be no exaggeration to say that he has listened to it hundreds of times on a lot of systems...some of them very nice. Anyhoo, he heard a voice in the background that he had never heard before..not that he couldn't understand what was being said, but that he didn't know it existed..it was clear as a bell.
That said, there is still work to be done. Obviously I have to actually finish the bass modules, and complete the baffle proper, but I also have a lot of tweaking yet to be done. I still have an upper midrange peak, but I'm pretty sure thats my untreated sheetrock walls as it doesn't appear unti after reaching a certain volume level. I also need to do a little more equalization of the bass, and work on the crossover transition between the disparate driver technologies. But there is no point doing that until I finalize my baffle and set up a measuring rig. I've taken it as far as I can tuning by ear...to many variables.
The reality is if it never got one scintilla better than it is right now, I would be very happy for a long time .
Casey
Ya..they are. Beasts with finesse
.Iv'e tried up to this point to not go overboard with the "proud papa" thing, but dang...these things kick some serious but. On the pure hammer ability I can reach ear bleeding concert levels in my moderate sized room with no signs of strain at all. My 20 year old head banging son came over with a friend to check out the latest addition of the bass modules..after cranking some Drowning Pool WFO, they actually asked to turn it down
. On the delicate side, musical nuances abound at normal listening levels. One example of this was when my brother, a serious Roger Waters fan, brought over one of his favorite test CD's "The Final Cut". It would be no exaggeration to say that he has listened to it hundreds of times on a lot of systems...some of them very nice. Anyhoo, he heard a voice in the background that he had never heard before..not that he couldn't understand what was being said, but that he didn't know it existed..it was clear as a bell. That said, there is still work to be done. Obviously I have to actually finish the bass modules, and complete the baffle proper, but I also have a lot of tweaking yet to be done. I still have an upper midrange peak, but I'm pretty sure thats my untreated sheetrock walls as it doesn't appear unti after reaching a certain volume level. I also need to do a little more equalization of the bass, and work on the crossover transition between the disparate driver technologies. But there is no point doing that until I finalize my baffle and set up a measuring rig. I've taken it as far as I can tuning by ear...to many variables.
The reality is if it never got one scintilla better than it is right now, I would be very happy for a long time .
Casey
A question
I would expect the main metal support structures of the ribbons to have a series of fairly high Q mechanical resonances. My guess is that these would be weakly excited, as the ribbon has distributed, symmetrical drive, and the support structure is very rigid.
Still, what "tone" do you get if you tap the steel parts, and does this correlate with the upper-mid colouration you can hear under some conditions? If the mechanical resonances were responsible, adding a bit of damping material and an extra bar somewhere to from a constrained layer might fix it.
This is just a wild thought, and probably irrelevant.
I would expect the main metal support structures of the ribbons to have a series of fairly high Q mechanical resonances. My guess is that these would be weakly excited, as the ribbon has distributed, symmetrical drive, and the support structure is very rigid.
Still, what "tone" do you get if you tap the steel parts, and does this correlate with the upper-mid colouration you can hear under some conditions? If the mechanical resonances were responsible, adding a bit of damping material and an extra bar somewhere to from a constrained layer might fix it.
This is just a wild thought, and probably irrelevant.
Hi PigletsDad,
Thank you for spending time thinking about my problem.
When you tap the frame you get a muted "thud" The combined weight of the frame & magnets is around 150 lbs., and I have over a yard of felt (as well as some Sorbothane) covering the steel in multiple layers. Add to that another hundred pounds between the stand and baffle. I'm fairly certain thats not what I'm hearing.
I think my issue is one of four things, or a combination of them. A cavity resonance, edge diffraction, untreated sheetrock walls, or electronics (by far my weak link at this point). As soon as I finish my baffles and bass modules I will start doing some measurements to hunt it down.
Casey
Thank you for spending time thinking about my problem.
When you tap the frame you get a muted "thud"
The combined weight of the frame & magnets is around 150 lbs., and I have over a yard of felt (as well as some Sorbothane) covering the steel in multiple layers. Add to that another hundred pounds between the stand and baffle. I'm fairly certain thats not what I'm hearing.I think my issue is one of four things, or a combination of them. A cavity resonance, edge diffraction, untreated sheetrock walls, or electronics (by far my weak link at this point). As soon as I finish my baffles and bass modules I will start doing some measurements to hunt it down.
Casey
I was still working on my first cup of coffee when I wrote that, and not so shockingly, I need to correct it
. I intend to have my measurement system online before I finalize my main baffle so that I can optimize it.Just to clarify, it isn't a horrible upper mid/lower treble peak. It only is evident on a few recordings. It might be as simple as replacing the 99 cent "freebie" patch cables I'm currently using.
Casey
I suppose that is a possibility...I do plan on experimenting with different ribbon profiles at some point...but the more I listen the more I'm leaning to an electronics issue. In fact I may have thought of a potential culprit. My source right now is a Toshiba 3950 with the Swenson mod. For those that aren't familiar, this mod basically bypasses the active filter at the output relying instead an a small shunt capacitor and the natural rolloff of the audio chain to get rid of the sampling frequency. This in turn feeds a stepped attenuator and the active crossover which is based around the LM4562..a very fast chip, and onto a Hypex UcD digital amp. My suspicion is that residual HF from the DAC is causing some ringing in the self oscillating digital amp. Hmmmm.
Casey
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