I think it's fine to discuss it here - or feel free to start a new thread called "the Perfect Squarewave Speaker"
Thanks
The juicy stuff is done by DRC 3.2.1 (by Dennis Sbraigon)
DRC: Digital Room Correction.
I started learning this software about 7 years ago and after hearing what was possible, there was no turning back for me.
This software runs command style in a dos window and any editing or "tweaking" must be done by modifying text files. What makes it a bit easier for me are scripts that I found at this site (which sadly don't appear to be there anymore) :
Alan's Astrophotos
What can now be found there however is a gui designed for the software to make it more user friendly. I have not used this so I can't comment on it personally. I would be happy to share the scripts but perhaps the graphical interface would be a more preferable method for most people.
I have tips to offer as far as tweaking settings, analyzing results, balancing channels etc... but I'm not sure how to proceed from here since I'm using about 6 pieces of software to accomplish all of this.
Please let me know how I can assist from here.
Ok, it sounds quite involved and maybe deserves its own thread as I mentioned above. If you can do this with front end processing on a netbook and sound card, I think many people would like to learn the ins and outs. Given that you are applying it to a single full range driver, I think it can stay in this forum where there is wider viewership rather than over in the digital IO forum. Up to the mods, but that's my vote. I think we would all lover to have a full range driver that can hot a square wave like that at different frequencies.
I think the square wave pics show that the linear distortions of the speaker are largely correctable with dsp. Remember though, that they are not showing the effects of non-linear distortions and so probably only reflect reality at low volume levels. I have shown elsewhere however, that the hypercube enclosure seems to reduce harmonic distortion compared to a typical sealed box. I have not yet attempted any comparison measurements of intermodulation distortion.
wesayso, I checked out your thread recently and I'm very impressed with your work.
wesayso, I checked out your thread recently and I'm very impressed with your work.
Apply that correction to 50 Vifa's and you would have one clean sounding system. Cone movement on 25 series parallel drivers is also much smaller than single driver for lower distortion. This might work really well on the Two Towers.
To assist us here some thoughts:
Probably a time consuming process loaded at your free time, suggests take guidance in steps as time and energy allow.
Looks hole process comprehensive and very grateful if you will support us your knowledge/experience.
Fine if stuff take a guidance approach, things as maneuvering new software or accuracy/precision in steps down the road expected be a local exercise.
Any experience with DRCDesigner? Digital Room Correction Designer Help
I had that one saved as well for later use..
Wesayso, no experience but seems gmad points to it, quote: "be more preferable method for most people" unquote. After download and unzip tried the v3.2.1 command prompt style version, needs some study and investigation but very responsive as other .exe files without GUI.
Digital Room Correction Designer software recommend ASIO interface to audio hardware, having a EssenceST and Delta192 not in use think will configure a dedicated desktop for this task.
The most flat response drivers i have laying around is TC9FD and a quick build cardboard box is needed.
In some days will get to start trials, regarding speed and progress guess xrk971 very soon mass reproduce these _┌┐_┌┐_┌┐_
.
Digital Room Correction Designer software recommend ASIO interface to audio hardware, having a EssenceST and Delta192 not in use think will configure a dedicated desktop for this task.
The most flat response drivers i have laying around is TC9FD and a quick build cardboard box is needed.
In some days will get to start trials, regarding speed and progress guess xrk971 very soon mass reproduce these _┌┐_┌┐_┌┐_
.
I just spent a few minutes fooling around with it...seems to work nicely. I used the version found here (not sure if it's different from the other):
Fixed version of DRCDesigner by Alan Jordan - Home Theater Forum and Systems - HomeTheaterShack.com
It uses a slightly outdated drc version (3.2.0) but that could probably be fixed. I made my usual edits to the text file associated with the preset I like to use (erb) and I seem to have gotten my usual results (just going by freq response alone). I think this is probably a good way to go....
HyperFAST AMT Edition...
For those of you lucky enough to have heard an Oskar Heil AMT tweeter in person - you know what I am talking about. I was lucky enough to get an ESS AMT tweeter yesterday. So I quickly set it up for a measurement. I turned the amp gain way down, about -12dB from where I normally test drivers at to make sure I did not over drive it on first sound. Well, it was still very loud! I was surprised because the manufacturer specs say 92dB at 1 watt - a decent number but not mind blowing. I hooked up a DMM and set 1200Hz sine wave at 1.2v - about as loud as my ears could stand. The driver clocked in at 93dB at 1m and 1.2v. That translates to 100.5dB at 2.83v!! Yes it is a "4ohm" driver - I measures DCR at 4.5ohms and this thing is supposed flat like a resistor across impedance sweep (because it is a resistor - no reactive coil). So my ears were not deceiving me. It took about -13.5dB of gain cut to match the effective 85dB woofer so there is gobs of headroom left. Ok, getting over the pleasant surprise of the sensitivity one will be surprised that the driver is heavy - about 14lbs - lots of magnet going on there. Could that be part of sensitivity? The other cool thing is that the pleated membrane is clear and sits at the middle of a symmetric V horn that goes front and back. It truly is a dipole radiator from the beginning. In the photo you can see light coming through the membrane slot in the middle. The little combs you see are alternating iron plates that direct the magnetic field through the membrane. The pleated membrane has flat aluminum wires bonded to it that make the pleats squeeze air out when excited. The diaphragm or membrane area is 5x larger than the frontal cross section area. Thus, there is a 5x leverage of membrane motion to air displacement. The membrane is very light so doesn't have any inertia hardly. It doesn't move much so HD is very low. So those are the basics of the AMT drive technology for those not familiar.
The sweep produced an amazingly flat spectrum from about 750Hz to +20kHz with no breakup. I can see why people say this thing is easy to cross over. I picked 700Hz at -24dB/oct and set it on top of my 5in Tang Band Hypercube bass unit also crossed at 700Hz.
Here is a photo of the AMT on top of the bass Hypercube:
The XO spectrum is in the next post (my apologies for the phone photo of the screen - my wireless was down and I couldn't send the graphic like I normally do - and browser on iPhone can't post more than 1 image per posst).
It integrates very well and appears to be a great candidate for a 2-way HF unit. So how does it sound? Special speakers take your breath away when you hear them for the first time and this is one of those moments. The sound was clean and clear, very open, extremely fast and able to articulate transients and percussions extremely well. The single adjective that best describes it is "naturalness" - its is like the instrument or singer is right there. As the music playing, I picked up the AMT (each time still surprised how heavy a 14lb tweeter is), and I hold it in my hands and it is like Diana Krall or Anne Bisson was put in a shrinking machine and placed right into the aperture of the AMT and singing her lungs off! Instruments like high hats sound like I have never heard them before. It is the articulation transient ability. I will show more data later but the impulse response is as I expected - no ringing at all. Just 1 peak and 1 overshoot of equal magnitude. A non FIR perfect impulse response.
This is one of those speakers where you hear new things and don't want to stop listening. Truly a special driver.
For those of you lucky enough to have heard an Oskar Heil AMT tweeter in person - you know what I am talking about. I was lucky enough to get an ESS AMT tweeter yesterday. So I quickly set it up for a measurement. I turned the amp gain way down, about -12dB from where I normally test drivers at to make sure I did not over drive it on first sound. Well, it was still very loud! I was surprised because the manufacturer specs say 92dB at 1 watt - a decent number but not mind blowing. I hooked up a DMM and set 1200Hz sine wave at 1.2v - about as loud as my ears could stand. The driver clocked in at 93dB at 1m and 1.2v. That translates to 100.5dB at 2.83v!! Yes it is a "4ohm" driver - I measures DCR at 4.5ohms and this thing is supposed flat like a resistor across impedance sweep (because it is a resistor - no reactive coil). So my ears were not deceiving me. It took about -13.5dB of gain cut to match the effective 85dB woofer so there is gobs of headroom left. Ok, getting over the pleasant surprise of the sensitivity one will be surprised that the driver is heavy - about 14lbs - lots of magnet going on there. Could that be part of sensitivity? The other cool thing is that the pleated membrane is clear and sits at the middle of a symmetric V horn that goes front and back. It truly is a dipole radiator from the beginning. In the photo you can see light coming through the membrane slot in the middle. The little combs you see are alternating iron plates that direct the magnetic field through the membrane. The pleated membrane has flat aluminum wires bonded to it that make the pleats squeeze air out when excited. The diaphragm or membrane area is 5x larger than the frontal cross section area. Thus, there is a 5x leverage of membrane motion to air displacement. The membrane is very light so doesn't have any inertia hardly. It doesn't move much so HD is very low. So those are the basics of the AMT drive technology for those not familiar.
The sweep produced an amazingly flat spectrum from about 750Hz to +20kHz with no breakup. I can see why people say this thing is easy to cross over. I picked 700Hz at -24dB/oct and set it on top of my 5in Tang Band Hypercube bass unit also crossed at 700Hz.
Here is a photo of the AMT on top of the bass Hypercube:
The XO spectrum is in the next post (my apologies for the phone photo of the screen - my wireless was down and I couldn't send the graphic like I normally do - and browser on iPhone can't post more than 1 image per posst).
It integrates very well and appears to be a great candidate for a 2-way HF unit. So how does it sound? Special speakers take your breath away when you hear them for the first time and this is one of those moments. The sound was clean and clear, very open, extremely fast and able to articulate transients and percussions extremely well. The single adjective that best describes it is "naturalness" - its is like the instrument or singer is right there. As the music playing, I picked up the AMT (each time still surprised how heavy a 14lb tweeter is), and I hold it in my hands and it is like Diana Krall or Anne Bisson was put in a shrinking machine and placed right into the aperture of the AMT and singing her lungs off! Instruments like high hats sound like I have never heard them before. It is the articulation transient ability. I will show more data later but the impulse response is as I expected - no ringing at all. Just 1 peak and 1 overshoot of equal magnitude. A non FIR perfect impulse response.
This is one of those speakers where you hear new things and don't want to stop listening. Truly a special driver.
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