Yes I have Win 7 pro, but not "ultimate". Thanks a bunch Wesayso. Several of my very old softwares work on this new Win7 pro (like Photoshop 5.5 from 15 yrs ago), but a few things don't work (Kai power tools from the mid 90's). I didn't know I could download better XP simulators.
I started hooking up my new ATEN switch and realized my keyboard needs to be USB for it to work, so now I've got to drive down to Fry's and get a new keyboard... Like all projects, you get going and then find out you still need one more part (sometimes over and over... OK, usually over and over...). Oh well, I'll get there eventually.
In the above EQ circuit, I believe it's R5 and R6 that adjust the height of the peak, and scaling the size of all four 0.1uF caps moves the peak frequency. Other resistors can be scaled too instead of the caps, but it could get messy if you don't know what you're doing. In any case you always want to verify the result with the SPICE program, or equivalent.
If you go to the Linear Technology website there's a free "LT SPICE 4" program downloadable. I downloaded it and installed it. I took a quick look and it looked real good, but I haven't actually used it yet since the circuits I've already modeled in the older PSPICE program on my XP machine wouldn't open in this newer LTSPICE program. I'd have to redraw it from scratch on the new machine.
I found this humorous Youtube video on Window 8 that some random guy made: http://www.youtube.com/watch?v=48ecX5DbX_E
I started hooking up my new ATEN switch and realized my keyboard needs to be USB for it to work, so now I've got to drive down to Fry's and get a new keyboard... Like all projects, you get going and then find out you still need one more part (sometimes over and over... OK, usually over and over...). Oh well, I'll get there eventually.
In the above EQ circuit, I believe it's R5 and R6 that adjust the height of the peak, and scaling the size of all four 0.1uF caps moves the peak frequency. Other resistors can be scaled too instead of the caps, but it could get messy if you don't know what you're doing. In any case you always want to verify the result with the SPICE program, or equivalent.
If you go to the Linear Technology website there's a free "LT SPICE 4" program downloadable. I downloaded it and installed it. I took a quick look and it looked real good, but I haven't actually used it yet since the circuits I've already modeled in the older PSPICE program on my XP machine wouldn't open in this newer LTSPICE program. I'd have to redraw it from scratch on the new machine.
I found this humorous Youtube video on Window 8 that some random guy made: http://www.youtube.com/watch?v=48ecX5DbX_E
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funny thing how people get hung up on their favorite GUI and forget what's running under it. A whole group of people are still hanging on to XP because they though that Vista was so bad. Well, Vista wasn't so bad. It made some blunders, particularly with hardware drivers, but I had no problem moving to Vista, primarily because I had to buy a new computer and Vista was loaded. Along came 7 and it was hailed as a godsend because it fixed everything that was wrong with Vista, and the GUI was pretty much the same. Now comes 8 and it is decried as awful because the GUI is different. Nonsense! Again forced into it by the need for a new computer, it took me maybe an hour do decipher the tiles on the start screen and I kind of like it. I don't miss the start menu for a minute. Of course 8.1 will make 8 look the same as 7 and everyone will be happy. Particularly me, since I can see some real advantages to 8.
Bob
Bob
Wow! That's all I can say.
Could you expand on the thinking behind the baffle design? Is the reason for double layers purely cosmetic, for instance? Are the Vifas clamped between the two layers or will you mount them with screws?
The Vifa's will be clamped somewhat but have their own mounting screws. I got the idea looking at the beautiful arrays Koldby showed. I tried to find some data to be sure the front plate with wave guide like holes wouldn't subtract from the performance of the speakers and found the previous linked page:
ViFAST - für 50Euronen (SDS 5 1/4 + Vifa 9 BN 119/8) **fertig! Weiche S.3** - DIY-HIFI-Forum
That shows a 9 mm bevelled baffle and it's effect on the on and off axis performance. I reduced the baffle thickness (front plate) to 6 mm after looking at it in my 3D program. That seemed to give the most continuous flow from cone to baffle. My thinking is it will help further reduce diffraction from the basket and hopefully help on and off axis response as well as look fantastic
.
The MLV sandwich is there to further deaden the baffle.
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I have thought about a grille but it would subtract from the looks/design.
Have you seen the line array from fellow member OPC?
http://www.diyaudio.com/forums/multi-way/193015-stupid-cheap-line-array-4.html#post2648779
A "sock" like that would still be possible...
Have you seen the line array from fellow member OPC?
http://www.diyaudio.com/forums/multi-way/193015-stupid-cheap-line-array-4.html#post2648779
A "sock" like that would still be possible...
I had the same thought re. the looks, but at the same time got chills thinking about prodding kid fingers and the like... It's tough to find a practical and good looking solution though.
Yep, I did see OPC's pictures and I immediately liked the "sock" idea. Nevertheless I actually got tempted to "steal" the design of your outer baffle layer, but make it removable and with grille cloth attached to it. (I am building a similar clone and am in the situation of having to decide on a grille solution myself)
Might not work in my case, but could be an option for you perhaps? Make the current mounting bolts fasten only the inner aluminium layer, then have separate mounting screws for the outer layer, attaching it to the inner one. Or even better - countersink neodymium magnets into the aluminium.
Yep, I did see OPC's pictures and I immediately liked the "sock" idea. Nevertheless I actually got tempted to "steal" the design of your outer baffle layer, but make it removable and with grille cloth attached to it.
(I am building a similar clone and am in the situation of having to decide on a grille solution myself) Might not work in my case, but could be an option for you perhaps? Make the current mounting bolts fasten only the inner aluminium layer, then have separate mounting screws for the outer layer, attaching it to the inner one. Or even better - countersink neodymium magnets into the aluminium.
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This is the discussion I've been hoping to find for the past year. Wesayso, do you realize that you are running the risk of creating a speaker that's so good, that your speaker building hobby will have come to an end? One perhaps important thing to keep in mind is the possibility that a driver gets damaged or is bad from the factory, and needs to be replaced. Hopefully that won't be too difficult to do.
For the grill assembly Roger Russel found some aluminum pieces at Home Depot that went top to bottom along the sides, that would hold a metal or plastic grill in place (described in his AudioXpress article). I have cats so a grill of some sort would be necessary.
This should be an absolutely superb speaker and listening experience if your room has the typical flat ceiling just above the top of the speaker. Your project is a big inspiration for the rest of us. I hope to get an active EQ circuit design together next week, after I get my computer stuff sorted out. Any EQ is only approximate, given all the real world variables, so if you don't have good tone controls in your system, that will be a good thing to look at next. I have a good tone control circuit I can share (4 section Baxandall). What country do you live in? I'm not familiar with the flag. France?
For the grill assembly Roger Russel found some aluminum pieces at Home Depot that went top to bottom along the sides, that would hold a metal or plastic grill in place (described in his AudioXpress article). I have cats so a grill of some sort would be necessary.
This should be an absolutely superb speaker and listening experience if your room has the typical flat ceiling just above the top of the speaker. Your project is a big inspiration for the rest of us. I hope to get an active EQ circuit design together next week, after I get my computer stuff sorted out. Any EQ is only approximate, given all the real world variables, so if you don't have good tone controls in your system, that will be a good thing to look at next. I have a good tone control circuit I can share (4 section Baxandall). What country do you live in? I'm not familiar with the flag. France?
Bob,
I look forward to your EQ circuit. Can I suggest a very nice ultra low noise op amp for audio use? Check out the TI lme49740 it has fantastic specs. Audio - Audio Operational Amplifier - LME49740 - TI.com
I hope to build it on a tiny 2 sq inch PCB with all SMT parts.
I look forward to your EQ circuit. Can I suggest a very nice ultra low noise op amp for audio use? Check out the TI lme49740 it has fantastic specs. Audio - Audio Operational Amplifier - LME49740 - TI.com
I hope to build it on a tiny 2 sq inch PCB with all SMT parts.
Hello Bob,
Thanks for the kind words. I've been planning this build for quite a long time. A lot of time went into optimising every little thing I could think of. It may very well be the last speaker I ever need, I do hope so. Even though it will always be fun to build other speakers, this is planned as my main system.
But I do have a garage etc...
I've made everything removable to be able to service the speaker (or change damping material). But it's a lot of bolts to get there
.Very curious how the active EQ will come out. I was planning on using JRiver media player with an EQ plugin like PLParEQ or similar. I am running a Xonar Essence ST soundcard that's quite good i.m.ho.
But that would still leave my radio/tv etc... without EQ. For that job I got the Behringer DEQ 2496, but your willingness to come up with an active EQ circuit design might change all those plans
.I'm from the Netherlands by the way (you can hoover with your mouse on a flag to check them, they will show it).
Would it be possible to glean a way to do the active EQ from all the sub units that SL uses for his Phoenix (which is a super complex 3 way XO and EQ)? Each block is an op-amp. For the IDS-25, we need an input buffer, the 20 dB at 30 Hz bass boost, the HF gradual slope boost, and the high pass above 20 Hz. I think it is 4 op amps and this is consistent with the photo of the circuit. A quad op-amp IC would let you implement this in a tiny space. Line level chokes (if needed) may be the biggest components.
Crossover/EQ
Crossover/EQ
xrk971, I'm not sure what you mean by "line level chokes". I'd avoid coils any time I can, but I definitely believe in passive Rf filters at the signal inputs, and 0.1uF caps from PS to GND within an inch of every opamp. You don't want to ask an opamp to do something it can't do well (Rf), and the power supply caps make phase margin more predictable and consistent. It could probably be said that all opamps are designed assuming 0 ohms for AC when the opamp looks at the power supply, from a few HZ to well into the mHZ. The big caps in the power supply create the 0ohms for the low frequencies, and the 0.1uF's near the opamps keep it 0 ohms well into the mHZ region.
If you know how to scale part values to get the gains and EQ shapes you want, and verify it in a SPICE or equivalent program, then yes the Linkwitz circuits may be an excellent choice. Linkwitz uses a gyrator topology to get the EQ shape. The circuit I've been using from an M&K active woofer is a "Laverne Terrace" (I probably mis-spelled that) topology. I read somewhere that it had a better transient response than something else... It uses more opamps than the Linkwitz method, but I'm not afraid of opamps. I have no idea which way is better, but I doubt if there would be a problem with either topology. Fewer opamps could mean less noise, so maybe I'll look at the linkwitz circuit again. The Linkwitz gyrator and one section of Baxandall for the gradual 3dB/octave rise to 20kHZ may be enough. Add an input buffer and you've got 4 opamps total. I'll model that first and see if it gets there.
Ideally I will come up with a circuit that creates the graph that Roger Russel recommends, and will also have trimpot adjustments for those who want to fine tune it with a calibrated mic and pink noise or whatever. That's my plan.
If you know how to scale part values to get the gains and EQ shapes you want, and verify it in a SPICE or equivalent program, then yes the Linkwitz circuits may be an excellent choice. Linkwitz uses a gyrator topology to get the EQ shape. The circuit I've been using from an M&K active woofer is a "Laverne Terrace" (I probably mis-spelled that) topology. I read somewhere that it had a better transient response than something else... It uses more opamps than the Linkwitz method, but I'm not afraid of opamps. I have no idea which way is better, but I doubt if there would be a problem with either topology. Fewer opamps could mean less noise, so maybe I'll look at the linkwitz circuit again. The Linkwitz gyrator and one section of Baxandall for the gradual 3dB/octave rise to 20kHZ may be enough. Add an input buffer and you've got 4 opamps total. I'll model that first and see if it gets there.
Ideally I will come up with a circuit that creates the graph that Roger Russel recommends, and will also have trimpot adjustments for those who want to fine tune it with a calibrated mic and pink noise or whatever. That's my plan.
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I do not know how to design active EQ's at all but could implement the circuit in AkAbak to see the shape of the response (kind of like spice I think). But I think it would be best left up to you as the expert for designing the circuit. I am only a dabbler in electronic circuits. I would love to learn more though. The topology terms you mention are new to me. I look forward to your design. Did you get a chance to look at that TI op amp?
Bob,
Please also look at the data from opc, a fellow member that has the arrays with the TC9. He posted his Behrenger curve here:
http://www.diyaudio.com/forums/multi-way/193015-stupid-cheap-line-array-7.html#post2762971
(also a very nice write up describing the array with subjective impressions)
He was very helpful to me in my design stadium as he was at that time the only one I knew with these arrays already built. Later in that same thread Koldby showed his results. I believe he chose not to use the array for the lowest frequencies. Both of them raved about the performance. Made me confident enough to go all out with mine.
Thanks for the heads up on the Stupid Cheap Line Array link. I'll check it out. Room acoustics are always a huge variable, so I'll take the Behringer curve with a grain of salt.
Right, although it'll give the broad requirements needed. The IDS25 itself has a fixed EQ curve, so I wouldn't get too worried. Unless you live in a rather unusual space, it should be close. One of the benefits of / purposes for using nearfield arrays of course is that they substantially increase the ratio of direct to reflected radiation.
I really prefer knobs myself. I called 2 Behringer reps a few years ago when I was considering re-building the analog sections of my DEQ2496, to see if I could get schematics. They said even they couldn't get them, and that Behringer stuff is not in their opinion "Hi-Fi". They said they couldn't even get any replacement parts. The above EQ might be excellent. It's hard to say without having access to the schematics. All we know for sure is that they did a pretty bad job in the past on their analog electronics.
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